ire ‘iy a Py ES ae ‘ BA AAT asiae cb DSSS SE TENE OU ie 5 et i ea patel oat 7 Ry ab sf AA pickhaaiuan de wine ee § antl a est pe th, Se Ae, eh ra Be 2h as come fae ear ut = ay ‘uot : an ar Pa , Phy an aS %, Up ad Hi | oe ft i i { BES O bf © | i } {uy! i ae s %, wi 1 lal (ct fl ea || te neers s seatet{) Lae tn) st ih | : (i ww , Hi | %, Ht Ayn iis ‘®) til aS stl ) ‘I Hp Ny ‘ Aa =A oof op 2 ache % fii HH Renee? rt) * f S | pep _ =i Nas ae AS ta hORAL oes *» | ee | ‘(ll HH BH | ‘i if i | <>. 2, Sabre tiara Ne, at em an : aie OO Rabanne eT aaah 4 ae ead wee WE VE, ue: ares is ARN, ea = YS AS PROCELTHNGS ENTOMOLOGICAL Volume Ninety SOCIETY Nee a dae Annual Report OW, 4R/O (Published September, 1960) exw. Tas PUBLISHED BY AUTHORITY OF Of. Me CORe THE HONOURABLE WILLIAM A, GOODFELLOW, MINISTER OF AGRICULTURE FOR ONTARIO ENTOMOLOGICAL SOCIETY OF ONTARIO OFFICERS 1958 - 1959 1959 - 1960 President: A. G. McNALLy, Guelph D. G. PETERSON, Guelph Vice-President: D. G. PETERSON, Guelph D. M. Davies, Hamilton Directors: J. A. Becc, Chatham Joan F. BronskILL, Belleville T. BurNETT, Belleville W. H. Footr, Harrow D. M. Davirs, Hamilton A. M. HEIMPEL, Sault Ste. Marie A. M. HEIMPEL, Sault Ste. Marie J. F. McALPInE, Ottawa W. B. WRESSELL, Chatham Secretary-Treasurer: W. C. ALLAN, Guelph | W. C. ALLAN, Guelph Librarian: W. C. ALLAN, Guelph W. C. ALLAN, Guelph COMMITTEES 1958 - 1960 Library Committee W. C. ALLAN, Guelph, Chairman J. H. H. Puuires, Vineland Station A. A. KincscoTe, Guelph B. V. PETERSON, Guelph Common Names Committee C. G. McNay, Ottawa, Chairman N. W. Y. Watson, Sault Ste. Marie L. A. MILLER, Toronto W. W. Jupp, London Publications Committee D. G. PETERSON, Guelph, Chairman D. M. Davies, Hamilton G. F. Manson, Chatham Correspondence about membership in the Society, or exchanges of publications should be addressed to the Secretary-Treasurer, Entomological Society of Ontario, Ontario Agricultural College, Guelph, Ontario. PROCELIUNGS of the ENTOMOLOGICAL SOCIETY Of ONTARIO Volume Ninety 7959 Aunuat Report (Published September, 1960) Published by authority of HONOURABLE WILLIAM A. GOODFELLOW Minister of Agriculture for Ontario EDITORIAL BOARD D. G. Peterson, Entomology Laboratory, Canada Agriculture, P.O. Box 248, Guelph, Ontario. (Editor) D. M. Davies, Department of Biology, McMaster University, Hamilton, Ontario. G. F. Manson, Entomology Laboratory, Canada Agriculture, Chatham, Ontario. The Ninety-Sixth Annual Meeting of the Society was held with the Ninth Annual Meeting of the Entomological Society of Canada and the Seventh Annual Meeting of the Entomological Society of America at Detroit, Michigan, November 30 - December 35 2959: CONTENTS Volume 90 I. SUBMITTED PAPERS L. A. MILLER and A. J. De Lyzer—A progress report on studies of biology and ecology of the six-spotted leafhopper, Macrosteles fascifrons (Stal), in southwestern Ontario.... 7 T. A. Ancus and A. M. Hermpet—The bacteriological control of insects.........00000000. 13 2] SLYKHuIsS—Current status of myte-transmitted plant VITUSES.......2.000.0... eee 22 B. V. PETERSON—New distribution and host records for bat flies, and a key to the North American species of Basilia Ribeiro (Diptera: Nycteribiidae)..........0000000000 30 L. L. Reep—Canada-United States cooperation in surveys and control of plant "SESS DULG ACES SRN Zea ose Ge eee A ee pe i Ree OE NCE en RPS 37 A. A. BEAULIEU—Should extension workers be closely associated with research? RRS Sect Me AIM CAC NIN Oy VIE WP OLIN occ s re ga ves aes woeea case Benue sne ooo ee inn ccs ian eee Sean. 40 G. F. Manson, L. A. MILLER, J. A. Becc and H. B. WressELL—Research-extension liaison.. 43 F O. Morrison—What training should extension workers receive at college?........0...000.00... 47 II. SCIENTIFIC NOTES L. J. Brranp—The nematode, Howardula benigna Cobb, 1921, parasite of the TOFOEORETD DSI I NESTS Tel 10 ae re Tc ee eee ee Bieter 53 D. M. Davirs—Microsporidia in a sperchonid mite, and further notes on hhydracarina and simuliids (Diptera) 2.0... .cceece tees tee ec cnecteeeee eee atecenercneetanenenna 53 C. V. Wape—An improved way to dry mount minute insects........0....0.000. Soca Aetace: cohen eee 5) Il. REVIEW ~C. G. MacNay—Summary of important insect infestations, occurrences and eaaoo reacKiGMiimnal areas Of Canada am BODO eel ceceecee rer pace ns ernee tenn escent 59 IV. THE SOCIETY Prem OS Oe ten O ULE A tituiedl > ME COLLINS co cscs the hein Coe nang si nng sheng Ae veeree ecu sosnn con feo te Dedeene eae eetge 77 Financial Statement ............ Eee Rieter ra rae cl, See RAT ws esp NBS GSA AG ices se vas oleh ahem 78 Publication policy and manuscript rules for the Annual Report .......0.0.0.0 cee 79 Rae EIN EDEN 5. nl eitprecedsdeeiss Sa IEMEL Pee AS Oy ER Ph ev ee SE CO Be ck RE RT Co paler 83 ITTED PAPERS — * , | A PROGRESS REPORT ON STUDIES OF BIOLOGY AND ECOLOGY OF THE SIX-SPOTTED LEAFHOPPER, MACROSTELES FASCIFRONS | (STAL), IN SOUTHWESTERN ONTARIO’ L. A. MILLER AND A. J. DE LyzER The six-spotted leafhopper, Macrosteles fascifrons (Stal), is the principal vector of the western, or California, strain of the aster-yellows virus and the only known vector of the eastern, or New York, strain. By transmitting the virus to celery, a host not susceptible to the eastern strain, George and Richardson (3) have shown that the western strain of the virus is present in southern Ontario. In 1957, hundreds of acres of lettuce, carrots, and celery were destroyed by aster-yellows in the rich market-garden areas in Ontario. In Manitoba, in addition to vegetable crops, losses were severe in sunflower and flax. Studies on the biology and ecology of the species in Canada were initiated in 1958 at the Research Station, Winnipeg, Manitoba, and at the Entomology Laboratory, Chatham, Ontario. Investigations were also conducted at the University of Manitoba; the results of this work have been published by Lee and Robinson (5). This report deals with the progress of the investigations in Ontario to the end of January, 1960. FIELD STUDIES : Population Sources Egg: Studies so far have shown that the six-spotted leafhopper overwinters in the egg stage in southern Ontario on winter rye, barley, and wheat. These hosts have been established by caging adults over them in the fall and watching for the appearance of nymphs in early May. Adults: In the fall of 1958, approximately 10,000 field-collected adults were added to cages containing winter rye or barley. None of them survived the severe winter of 1958-59. Of interest, however, are results obtained in January, 1960, of ‘a similar experiment. In August, 1959, lettuce was sown in four, 9- by 6- by 6-foot outdoor rearing cages. When the lettuce was about two inches high, field- collected adults were added and large populations developed in each cage. At the end of September winter barley was broadcast in two of the cages and winter rye in the other two. In early December the cages were removed to expose the areas to winter conditions. From then until early January the minimum temperatures at the soil surface were well below freezing on most days, falling to —4° F. on December 22. Freezing rains and a near record snowfall of 11 inches on December 20 were part of the weather conditions in the period. On January 7, 1960, four square feet of rye sod were brought into the laboratory from one of the previously caged areas. The sod was frozen to a depth of three inches. When the matted rye was separated, numerous moribund adults were observed either on the soil or in depressions. Within one hour, seven adults had become active and, after one day in the laboratory, 72 adults (about 10 dark- colour phase to one light-colour) and 15 nymphs were recovered. Most of the nymphs were dark (some almost black) and were in the second, third, fourth, or fifth instars. Subsequent observations failed to show adults present. _ These observations are offered as an indication that in some years, depending on the weather conditions, the species may overwinter in the adult stage. Undoubtedly a heavy natural mortality will occur during the remaining winter months. It must also be remembered that the populations in the cages were extremely concentrated. If overwintering in the field does occur, it is probably 1Contribution No. 4, Entomology Laboratory, Research Branch, Canada Agriculture, Chatham, Ontario. Proc. ent. Soc. Ont. 90 (1959)—1960 7 in very low numbers and of litile significance. In any case, the conditions in the study areas will be followed with interest until the spring of 1960. The possibility of the odd adult overwintering in New York State has been suggested — by Hervey and Schroeder (4). To date, therefore, there is no positive proof that the adults can overwinter in Canada and the northern United States. It would seem, moreover, that the adults first found in the spring could not have developed from overwintered eggs. Thus, in 1958 at Chatham, the first adults were taken on May 13 and a few third-instar nymphs on May 16; in 1959 the first adults were swept from winter rye on May 8 and, on May 11, third-instar nymphs were found on winter wheat. — The early population, therefore, must migrate into southern Ontario. Important points in support of the migration theory, which at times is controversial, are: (1) The sex ratio of the adult population in early spring is predominantly female, often as high as 20 to one. In laboratory studies, the sex ratio of the species was established as one to one. If the spring adult population developed from overwintered eggs the ratio should be close to one to one. The males do not live as long as the females (Table III) and, being less vigorous, theoretically fall by the wayside on the flight north. This adequately accounts for the predominance of females. : (2) In thousands of net sweeps in numerous fields of winter wheat, rye, and barley, ditch banks, roadsides, pastures, and woodlots, the nymphal population has been far too small to account for the high adult population that develops so rapidly over wide areas. (3) The greatest population density is always found in spring-seeded oats. (4) The early spring population consists of the light-colour phase of the species. Since the dark-colour phase is common in the fall it would be expected that some of these specimens, if they overwintered, would be included in popula- tion samples in the spring. Migration of ths six-spotted leafhopper has been studied by Chiykowski and Chapman (1) who, for a number of years, have followed the northward movement of the species from the southern United States, through the mid-west, and into Manitoba. These authors have located important leafhopper breeding areas in the Ozark Mountains in Missouri and Arkansas but believe the main population source 1s further south in Louisiana and eastern Texas. It is probably significant that the general airflow for May that would affect the movement of leafhoppers into southwestern Ontario takes place in a northerly direction from the Gulf of Mexico, through Louisiana and Arkansas and then north-westerly across Illinois, Indiana, and southern Michigan. Generation Studies To study the number of generations in the field the first nymphs that hatched in the overwintering cages were transferred to an 18- by 18- by 26-inch cage where development could be followed more closely. A flat of oats was supplied as needed. When approximately 50 adults had emerged, they were transferred to a similar cage for oviposition. The adults were released as soon as a new generation of nymphs began to appear. This procedure was continued until pee had obviously ceased in the fall. The results of this study are shown in able I. Five generations of adults were reared from this overwintered egg source as compared to four generations from 50 migratory adults caged on May 19, the first date that adults were fairly numerous in the Chatham area. It is of interest to note that a generation was completed in the field in 28 days, whereas in the laboratory at a constant temperature of 80° F., this period was 34 days and, at 70° F., 40 days. Proc. ent. Soc. Ont. 90 (1959)—1960 a Table I Number of generations of the six-spotted leafhopper reared under field conditions from overwintered eggs, Chatham, Ontario, 1959 | ) Nymphs Adults Period (days) _ Generation Adults caged appeared appeared adult to adult verwintered Sept. 8 to Oct. 7, 1958 May 3, 1959 May 24, 1959 First May 24 June 1 june: 21 28 Second Junie, 21 June’ 29 July 20 29 Third July 20 July 31 Aug. 17 28 Fourth Aug. 19 Aug. 29 Sept. 14 28 Fifth : sept. 16 OGt.. 77 = Average 28 * Some nymphs matured to fourth instar but no adults developed. The occurrence of the five generations in cages was not reflected in five _ population peaks in the field as determined from net sweeps. After the migratory population began to arrive in mid-May there was a steady increase in adult numbers from all sources until about the end of June. The population remained very high throughout July and August and began a gradual decline in mid- September. Adults were swept from winter barley as late as November 26. This broad picture is understandable when one considers the amount of overlapping of generations that must occur in a species that has at least the following - characteristics: (a) at least two distinct sources of population that give rise to progeny at _ different times (b) vast numbers of adults involved (c) a long life span of gravid females (Table III) and a period of oviposi- _ tion of about one month (d) numerous hosts on which the duration of the life stages may be signifi- cantly different (e) nymphs are present in all stages on various crops from early May until _ late September. _ These, plus the vagaries of weather and local factors, are compounded to give _ this general, but rather definite, picture of the species as it occurs in southwestern Ontario. | Preferential Cereal Hosts Early in these studies it was evident that cereals were a very important link ‘ in the chain of food plants that contribute to the extremely successful establish- ment of the species in southwestern Ontario. Broadly speaking, the species begins and ends its life on cereals. Adults disperse to vegetables, ornamentals, and other _ vegetation in early summer when the cereals begin to ripen and lose their _ succulence. When the vegetable crops have been harvested, adult movement 1s _back into the fall-seeded winter grains where the species overwinters in the egg stage. ‘To compare the relative preference of various cereal hosts to the six-spotted _ leafhopper, rye, oats, barley, and wheat were sown on June 2 in plots each 200- by 20-ft. One hundred net sweeps were taken in each plot on a series of dates. The results of this study are given in Table II. ee ee a en ae ea eee ee ere pe ae : Se ae , =p a ¥ iu It is evident that oats, barley, rye, and wheat are preferred in that order. It is also concluded from this and from a study of numerous fields in the spring Proc. ent. Soc. Ont. 90 (1959)—1960 9 Table II Number of adult females, males, and nymphs in 100 sweeps over rye, oats, barley, and wheat on the dates indicated, Chatham, Ontario, 1959 Rye Oats Barley Wheat Totals Date 9g N § g N= Og No? so June. = 18 4.2 0 17 1) 00: 9. 5 0 ) 5 00 ae | 24°25 4° °.0 535 8. 0 333-15 0.25 * 9 Oe 0 6 60 54-0 74 34~ 0 14 20° 02102 ie July oka ae al 86.54 24 50 24 12.26 8. -2 Soe Ih. 92 76. 4.224 60. 20-140 120-0 4°44 367 1G Oe eee 22.60 44. 44 232 76 40° 68 44° 7/6 16 8 J25e376e eee 29 8 8 24 116..48 5624-28-56 16 16 32 ieee Aug. 5 4 8 12. 52°52 44-64-48 52. 0 (8° 16820 ee 12°..16 4-4 4. 4.52 2-4-8 40 0° (0 320 ees Totals 289 222 94 826. 367 236 466 326 240 142 110 158 1723 1025 728 “Nymphs 305, 46-56 that winter wheat is not an important host of the six-spotted leafhopper in Ontario. Sex Ratio In 1958 and 1959, 149 population samples were taken in various crops for sex-ratio determination. The ratio in 15,396 adults was 9,823 99 to 5,573 ¢¢ or approximately 2 99 to 1 g. As mentioned previously, this deviates from the established one to one ratio because of the longer life span of the female. Parasitism ‘The only parasite observed in these studies was a hymenopteran, Epigona- topus plesius (Fenton) [Dryinidae]. The wingless female attacks adults or nymphs, paralyzes its prey, and lays its eggs in the body of the host. As the resulting larva grows it ruptures the abdomen of its victim and then appears as a sac attached to one side of the abdomen (Fig. 1). Usually there is only one parasite per host but occasionally two are present and, on one occasion, an adult was observed with three distinct ruptures. At maturity the larva emerges from its host, spins a cocoon on nearby vegetation, and overwinters in this manner. In 1959, approximately two per cent of 19,000 adults examined were visibly parasitized. For actual parasitism this figure should be somewhat higher because it does not take into account parasitized adults in which ruptures had not yet developed. Some specimens of the early migratory population were captured with ruptured abdomens and it is interesting to speculate whether the parasitism occurred at the source of migration, enroute, or on arrival of the adults. Epigonatopus plesius was first recorded as a parasite of the six-spotted leafhopper by George (2) in 1959. It is not considered of economic importance. LABORATORY STUDIES Rearing Non-viruliferous colonies of the six-spotted leafhopper are easily maintained on oats, barley, and rye. Wheat was also used as a host but the results were not as successful as with the other cereals. Best results were obtained when the species was cee at about 75° F. and the relative humidity maintained as high as possible. Proc. ent. Soc. Ont. 90 (1959)—1960 10 REE SS RAAaas Saas VwSesw Ay SH EAS Fig. 1. Six-spotted leafhopper adult parasitized by Epigonatopus plesius (Fenton). Viruliferous colonies were reared successfully in these studies on diseased aster, periwinkle, plantain, Bibb lettuce, carrot, and celery. Other hosts on which we have reared the species are turnip, corn, chickweed, purslane, dandelion, potato, fleabane, and chrysanthemum. Duration of Life Stages A technique was developed whereby the progress of individual specimens could be easily followed. One newly-hatched nymph was transferred to a single oat seedling in a two-inch flower pot. A 12-inch section of one and one-quarter- inch glass tubing was then placed over the seedling and forced to the bottom of the pot. The top of the tubing was covered with cheesecloth held in place with an elastic band. The oat seedling remained green under artificial light and usually did not have to be changed throughout the experiment. Leafhopper mortality was very low. The nymphal moult always occurred while the rostrum was deeply inserted in the leaf tissue. The cast skin remained in situ firmly anchored by the old rostrum and was easy to locate. In these studies the pre-oviposition and the incubation periods of the egg each averaged eight days. The duration of each nymphal instar and the longevity of 16 adults are given in Table III. SUMMARY In southwestern Ontario the six-spotted leafhopper, Macrosteles fascifrons (Stal), overwinters in the egg stage on wheat, rye, and barley. Evidence is also presented that suggests this insect may overwinter in the adult stage. The migra- Proc. ent. Soc. Ont. 90 (1959)—1960 ll Table III Duration of nymphal instars and longevity of adults reared under constant illumination at 80° F., Chatham, Ontario, 1959 Total nymphal Longevity Total period Specimen Duration of instar (days) period of adult (nymph number First Second Third Fourth Fifth (days) (days) Sex + adult) ] 3 2 3 3 3 i 38°. Gee 52 2 3 Z 3 3 5 14 abu 2 56 3 2 2 3 3 3 V3 ou 2 TZ 4 3 2 2 2 4 13 29 Jb 42 5 5 2 2 3 3 13 43 Jb 56 6 2 3 Z 2 4 hS 23 2 46 7 3 e 2 2 3 13 31 Jb 44 8 2 3 3 3 3 14 20 a 34 9 3 2 ye 4 4 15 42 & 57 10 3 2 2 4 2 13 13 a 26 1] 3 2 2 3 3 13 27 eh 40 12 3 3 2 3 % he 22 J 36 13 3 Z Pe 3 3 £3 23 e 39 14 2 2 2 2 3 1] 23 Jb ou {5* 3 2 3 2 4 14 49 2 63 16% 3 2 o 4 2 14 65 Jb 79 Average (524 eo ee 29 Sul La Sas 48.5 *These specimens were reared in an outdoor insectary and were, therefore, exposed to natural fluctuations of light and temperature. Average longevity of 99, 42.2 days Average longevity of ¢¥, 29.6 days tory population arrives about mid-May and produces at least one complete generation on spring-seeded oats. As the cereals ripen, adults disperse to vegetables, ornamentals, and other vegetation. In the fall, movement is back into winter cereal crops. In 1959 there were four generations of adults produced from migratory adults and five generations from the overwintered egg source. Although the sex ratio of the species is one to one, females predominate in field populations in the ratio of two to one. This is accounted for by a longer life span of the female given below. Parasitism of adults by a hymenopteran, Epigonatopus plesius (Fenton) [Dryinidae], was approximately two per cent. The six-spotted leafhopper was reared in the laboratory on oats, barley, rye, wheat, aster, peri- winkle, plantain, lettuce, carrot, celery, turnip, corn, chickweed, purslane, dandelion, potato, fleabane, and chrysanthemum. At 80° F., the nymphal period averaged 13.2 days, and the longevity of adult females and males was 42.2 days and 29.6 days, respectively. i LITERATURE CITED (1) Cutykowskt, L. N. and CHapman, R. K. (1956). Long distance migration of the six-spotted leafhopper in relation to aster yellows in Wisconsin. Proc. Eleventh Ann. Meeting North Central Branch ent. Soc. Amer. 11: 53. Proc. ent. Soc. Ont. 90 (1959)—1960 12 (2) Grorce, J. A. (1959). Note on Epigonatopus plesius (Fenton) (Hymenop- tera: Dryinidae), a parasite of the six-spotted leafhopper, Macrosteles fascifrons (Stal), in Ontario. Canad. Ent. 97: 256. (3) Grorce, J. A. and RicHarpson, J. K. (1957). Aster yellows on celery in Ontario. Canad. J. Plant Sci. 37: 132-135. i) bleRvEY, G. E.R: and SCHROEDER, -W. T. (1919), Cheryellows disease of carrot. N.Y. State Agr. Expt. Sta. Bull. 737. pelEr, PL E. and Rosinson, A. G. (1958). Studies on the six-spotted leaf- hopper, Macrosteles fascifrons (Stal), and aster yellows in Manitoba. Canad. ee lamet Ser 35: 320-327. (Accepted for publication: March 9, 1960) me SS ee Oo-- THE BACTERIOLOGICAL CONTROL OF INSECTS’ T. A. Ancus AND A. M. HEIMPEL Past and contemporary studies have led to an understanding of some of the attributes necessary in an effective bacterial control agent. An ideal bacterium would be highly virulent, able to breach the defences of the healthy feeding Insect, and by some means bring about its death. The organism should cause death even when a small number of bacteria are ingested and it is also desirable that the virulence be a stable characteristic. The bacterium should have a dormant phase in its life cycle resistant to ultra-violet radiation and drying, enabling it to remain viable and virulent while exposed on the plant or in the insects’ habitat. Since most bacteria are extremely sensitive in the vegetative or growing phase, the insect pathogen should not readily discard its resistant form until ingested by the insect. The resultant disease should have a short incubation period, for if too long a period ensues between contact and death of the insect, the damage to the crop being attacked may be considerable. ‘The pathogen must be reasonably specific for the insect pest it is being used against and inactive against the host plant, useful parasites and predators, and most important of all vertebrates. It is also important that the micro-organism be easy and relatively cheap to produce in sufficient quantity for widespread use. The product must be sufficiently stable to permit production and storage before the growing season begins. In the review that follows some known pathogens are discussed in the light of these criteria. Included is some comment on the possibility of practical utilization of entomogenous bacteria. In the early years of this century d’Herelle (17) isolated from diseased grasshoppers a bacterial species called Coccobacillus acridiorum which he used in control work. Some success was claimed, and great interest and high hopes were generated, but unfortunately these were not realized. ‘Those seeking to repeat d’Herelles’ work found that the bacterium very rapidly loses its virulence on artificial media so that cultures of the pathogen that were later released could 1Contribution No. 9, Insect Pathology Research Institute, Research Branch, Canada Department of Agriculture, Sault Ste. Marie, Ontario, Canada; presented as part of a symposium on biological alternatives to chemical control at the joint meeting of the entomological societies of America, Canada and Ontario at Detroit, Michigan, November 30 - December 3, 1959. Proc. ent. Soc. Ont, 90. (1959)—1960 13 well have been avirulent. It was also found that so-called pure cultures in use were, in fact, cultures of altogeiher different species of bacteria. Some of the workers reporting negative results had used d’Herelles’ organism not against Schistocerca spp., its original host, but other species of locusts. These are but a few of the complications that arise in assessing this early attempt at insect control. It is obvious that there was insufficient attention paid to the questions of stability of virulence, and the host specificity of the pathogen (7). In 1957 Stephens (22) reported on a number of bacterial strains isolated ~ from diseased codling-moth larvae, Carpocapsa pomonella L. These strains were almost identical with Bacillus cereus Frankland and Frankland, and in labora- tory experiments it was found that several of them had a high level of virulence for codling-moth larvae. In field experiments, however, the bacteria were not effective (23). It was established that when a suspension of spores of Bacillus cereus is sprayed onto apple foliage, some of the spores germinate on the leaf and so the resistant spore stage is replaced by vegetative cells which are apparently killed by desiccation and sunlight. The most important reason, however, for the inability of the pathogen to control the insect is to be found in a study of the habits of codling-moth larvae. The emerging larvae travel only a short distance before entering an apple, and become infected only if a lethal dose is ingested at the point of entry, and it is uneconomic to maintain a lethal dose at all potential entry sites. In general, insects feeding on exposed foliage are more easily combatted than insects which mine or feed inside buds or fruit because the known bacterial pathogens must be ingested to become effective. The usefulness of a bacterial pathogen therefore may be limited by the life habits of the insect. Bucher and Stephens (8) isolated from diseased grasshoppers a strain of Pseudomonas aeruginosa (Schroeter) Migula which under laboratory conditions showed some promise as a useful bacterial pathogen. In an extensive series of studies, the host-parasite relationship was investigated and it was discovered that the bacterial isolate was very sensitive to drying. When the conditions which prevail in parts of the Canadian Prairies are recalled, it is evident that desicca- tion could well be a limiting factor in the use of Pseudomonas spp. against grasshoppers. In these studies of Bucher and Stephens we have an example of the fact that promising laboratory pathogens are often limited by field conditions. The ideal bacterial species for the control of insects is yet to be isolated but there is a group of organisms that come very close to fitting the requirements; these are the causative agents of the so-called “milky-diseases’’ which have been so extensively studied by Dutky, Beard, White, and others at the Moorestown laboratories of the U.S.D.A. (6, 26). The best known are Bacillus popilliae Dutky and Bacillus lentimorbus Dutky which cause a lethal septicemia in the Japanese beetle, Popillia japonica Newm. The organism persists in the soil as a resistant spore and is ingested by the grub or larva as it feeds. Once inside the gut, the spore germinates and the vegetative cells of the organism penetrate the gut wall in some way and enter the hemocoele where their numbers increase rapidly. Thse vegetative cells sporulate and the thick-walled refractile spores are seen through the translucent integument, so that the larvae display the character- istic appearance which makes the name “milky-disease” very appropriate. The larvae die in the soil and eventually disintegrate, releasing the spores to be ingested by other larvae. The milky-disease organisms are highly virulent, and if the organism is applied as a spore-dust it will persist in the soil in a virulent condition for long periods. The milky-diseases are, however, not rapid in their action; the incubation period, depending on the weather, may extend from 2 to 4 weeks. The organism is a fastidious pathogen and does not grow readily on laboratory media. The infectious material is produced by inoculation into the body cavity of larvae which are then incubated until they contain billions of spores per animal. The Proc. ent. Soc. Ont. 90 (1959)—1960 14 larvae so treated are then dried and ground, and the powder extended with suitable fillers. The method of production is of necessity somewhat involved and affects price and availability. There are a number of studies in progress in the U.S.A. to develop a method for producing spores of the milky-disease organisms in synthetic media. Although Bacillus popilliae is the best known of the bacteria affecting beetle larvae, it is by no means an isolated case. The work of Kiken et al in Germany, of Beard in Australia and Dumbleton in New Zealand indicates that there are a number of beetle pathogens. Unfortunately, time permits only a passing reference. With the milky-diseases we are utilizing a natural disease which is present in many beetle populations. In nature the disease spreads very slowly, and so man has intervened to increase artificially the numbers of the pathogen and accelerate the spread. In summary, Bacillus popilliae is a virulent, stable, permanent, safe, highly specific and easily used pathogen. Another group of pathogens has been studied extensively, namely, the bacteria related to Bacillus cereus. ‘The codling-moth pathogen isolated by Bucher and Stephens has already been discussed. A similar organism was isolated by Heimpel (12) from larch sawfly larvae Pristiphora erichsonit (Hertig) in 1952. In investigating the mode of action of this strain, Heimpel found that it produced a toxic exoenzyme later identified as lecithinase C, a phospholipase which acts on the cell phospholipids of the larval gut. When ingested by larch sawily, the spores of this strain (Pr 1017) germinate in the gut and vegetative growth follows. As a normal consequence of vegetative growth, the toxic exo- enzyme is produced and gut damage occurs permitting entry of the bacteria into the body cavity and death by septicemia. It was also found that some strains produce more lecithinase than others and that toxicity can be correlated with the ability of a strain to produce the exotoxin. It is obvious that bacteria cannot become established unless the gut of the host insect is a favourable environment. When Pr 1017 was tested against other insect species, it was found that resistant species had alkaline midgut contents. Heimpel (13) then demonstrated that the limiting factor was pH. In the resistant insect species the alkaline condition inhibits germination of the ingested spores, or vegetative reproduction of the bacteria, or the activity of the exoenzyme. In stained sections of the midgut of larch sawfly (a susceptible species) in- fected with a high lecithinase-producing strain of B. cereus, the peritrophic membrane is no longer visible, the brush border is damaged, the cell nuclei appears abnormal, and clumps of basophilic granules occur in the cytoplasm (13). There is another group of bacteria, closely related to Bacillus cereus, found associated with diseased insects; these are crystalliferous bacteria (14). The best known is Bacillus thuringiensis var. thuringiensis, Berliner, (15) a spore-former which grows well on simple laboratory media and which when ingested by larvae of the flour-moth Anagasta kiihniella Zeller causes a lethal septicemia. Contem- porary interest in the field use of B. thuringiensis stems very largely from the work of Steinhaus and his colleagues with the alfalfa caterpillar in California (20). In his pioneer studies with flour-moth larvae, Mattes (19) indicated that ingested spores germinate in the insect gut, and the resulting vegetative rods migrate between the gut cells into the hemocoele where they cause death of the host by septicemia. This explanation prevailed until it was called into question by Heimpel’s studies and by results obtained with the silkworm pathogen B. thuringiensis var. sotto Aoki and Chigasaki. The sotto variety was isolated from diseased silkworm (Bombyx mori L.) about 50 years ago by Ishiwata (18). His work was extended by Aoki and Proc. ent. Soc. Ont. 90 (1959)—1960 15 Chigasaki (5) who found that a sporulated culture of the isolate caused a ee lethal paralysis when ingested by silkworm larvae. They also established that — ingested spores did not germinate in the insect gut, therefore, death could not be as a result of some product produced by bacterial growth in the gut. When it is recalled that the silkworm gut is strongly alkaline (from pH 9.3 - 10.4), it is easily understood why spore germination is inhibited. Aoki and Chigasaki concluded that a pre-formed toxin was involved. Little or no work was done on the sotto toxin until the question was reopened in Canada in 1952, when it was discovered that by using silkworm gut-juice, and later suitable alkali solvents, a soluble toxin could be obtained ‘that would cause paralysis in larvae ingesting the product (1). At the same time Hannay (10, 11), also working in Canada, rediscovered crystalline parasporal bodies in sporulated cultures of Bacillus thuringiensis var. thuringiensis and suggested that they might be implicated in the “insect. disease caused by this organism. It was then established that sporulated cultures of B. thuringiensis var. sotto also contained crystals, that these crystals were the source of a toxic _ protein that caused the paralysis of silkworm larvae (2). Correlation of toxicity s = x = Sa | sl Fig. 1. The foregut epithelium of a normal silkworm larva. Note the normal appearance of the cells, particularly their close attachment to the basement membrane and one another. The gut musculature is in tonus. Proc. ent. Soc. Ont. 90 (1959)—1960 16 pe, wre with the presence of crystals has also been shown in other varieties of B. thurin- giensis by other workers (4). The crystalliferous bacteria have been widely tested and it has been shown that many Lepidoptera are killed by these strains (there are more than 80 known susceptible species) (24). When silkworm larvae ingest either the toxin or raw crystals they soon cease feeding because the gut becomes paralyzed, muscular co-ordination is then affected, and finally the insect becomes completely para- lyzed. If at various stages of the toxemia the blood is sampled, it is found that it becomes progressively more alkaline (14). This correlation of general paralysis and increased blood alkalinity is also found in some hornworms and one other silkworm. The general paralysis is caused by the change in blood pH for a similar paralysis occurs when blood pH is increased by injections of sterile non-toxic buffer (3). Most of the susceptible Lepidoptera, however, do not exhibit general paraly- sis (4). Typically, soon after toxin is ingested, feeding ceases and the insect becomes sluggish and dies in from 2 to 6 days. There is no increase in blood alkalinity. If an insect is fed foliage coated with barium sulphate, X-ray shows Fig. 2. The foregut epithelium of a silkworm larva 60 minutes after ingest- ing toxin. The distal ends of the cells no longer stain evenly. They have become detached from the basement membrane and one another. The gut musculature is abnormal in appearance and is no longer in tonus. . Proc. ent. Soc. Ont. 90 (1959)—1960 Uy that the food and the opaque marker chemical are rapidly passed down the gut — by peristaltic action. If, however, the leaves are coated with a mixture of barium sulphate and toxin, movement of the food ceases very soon after the toxin reaches the anterior midgut (16). An examination of stained sections of gut from normal and infected insects indicates that the anterior midgut is the first area damaged by the toxin.<((Pies. { and-2)- | Although it is known that the site of action in all susceptible larvae tested is the midgut, the precise nature of the damage is yet to be elucidated. In the silkworm, the integrity of the midgut is destroyed and it has been suggested that the cell-cementing substances are altered (16). Obviously, there is some difference in the mode of action of the toxin in those species which exhibit general paralysis in addition to gut paralysis. In test tube experiments the toxic protein does not dissolve below pH 10.5. Some susceptible species of insects, however, do not exceed pH 9.5 in any area of the midgut. This anomaly became understandable when Young (25) showed that the crystals of B. thuringiensis var. alesti dissolved more readily in the presence of thioglycollic acid, which is, of course, a strong reducing agent. The midgut contents of most Leptidopterous larvae contain reducing agents and so the response may vary with the composition of the midgut contents rather than because of a profound difference of midgut structure. To summarize, many crystalliferous strains when grown under certain conditions produce a parasporal body or crystal composed of protein which damages the gut of many Lepidopterous larvae. The damaged gut becomes non-functional and feeding ceases. Death follows in from 2 to 6 days. } It is the rapid inhibition of feeding that makes the thuringiensis group attractive as biological control agents. Feeding ceases in less than an hour after ingesting toxic material and this is equivalent to rapid knockdown. The pretec- tive effect of a coating of a culture of B. thuringiensis is seen in Fig. 3. Feed- ing is not immediately inhibited, for we must sacrifice that quantity of foliage that carries a lethal dose of our microbial insecticide to the larval gut. Commercial preparations of B. thuringiensis are now being field tested. How do they measure up to the ideal pathogen? The thuringiensis varieties are indeed virulent; the lethal dose for silkworm in terms of whole dried sotto culture is less than a millionth of the larval body weight, that is, less than 0.5 ug/gram of insect, which is roughly comparable to DDT (2). The virulence has also been confirmed in many field trials (24). Is the virulence of the thuringiensis varieties stable? The contemporary studies on the sotto strain were initiated with a culture that had been carried on laboratory media for more than 50 years. In the very first toxicity tests it was as virulent as the original isolate. A note of caution must be interjected here, for there is evidence to indicate that the amount of toxic material produced varies with the way in which the bacteria are grown. The ability to produce the toxic material is, however, a stable characteristic. Because the thuringiensis insecticides depend largely on the action of the crystal protein, persistence must be measured in terms of this body and not the spore. In our laboratory we have water suspension of pure crystals, held at 3° C., which are still active ated ai: years’ storage. Indeed, with the thuringiensis varieties the problem 1s not to extend the activity period of the crystal but to develop an application method that will fully exploit its stability. The spores of B. thuringiensis are also fairly resistant to field conditions, and this is important since there is evidence to suggest that with some insect species the spore has a function in pathogenesis, initiating septicemia following the toxemia induced by the crystal (unpublished results). Although the affected insects may not die for several days after ingesting a thuringiensis insecticide, feeding ceases in less than an hour so in effect it can Proc. ent. Soc. Ont. 90 (1959)—1960 18 Fig. 3. Feeding of Anisota senatoria larvae on young oak trees. ‘The tree on the left was sprayed with B. thuringiensis. The tree on the right was not sprayed and it has been defoliated. . be said to act rapidly. The large quantities of material being tested were produced by the fermentation industry and although such knowledge is in commercial hands, it is obvious that the technical problems attending mass propagation have been solved. ‘The question of cost is also an imponderable, but it is common knowledge that microbial preparations presently envisaged will be competitive with existing products. As noted earlier, the B. thuringiensis varieties are closely related to Bacillus cereus, and some taxonomists include in the cereus group the anthrax bacillus. This has led to speculation about the possibility of mutant forms of thuringiensis strains arising that could affect vertebrates. Dr. Steinhaus has dealt with this question at length in a recent paper. He concludes as do others who have worked with the thurimgiensis strains that they are safe to use in the field (9, 12). A Proc. ent. Soc. Ont. 90 (1959)—1960 19 more likely source of danger, in our opinion, would be the accidental contamina- tion of a batch with a harmful strain of B. cereus but this could be easily prevented by adequate supervision of manufacture and testing. When the milky-disease organisms are used, an infectious cycle of long duration follows the initial build-up phase. This is not the case with the thuringiensis preparations where the active agent is a non-living crystal that does not initiate an infection but merely induces a toxemia. In short, when we use thuringiensis preparations we are relying principally on a chemical insecti- cide of microbiological origin. And just as we use yeasts to produce wine from sugar and Acetobacter to produce vinegar from wine, so we use the thuringiensis organisms to convert part of a harmless nitrogen-carbon substrate into an insecticidal protein. The maximum production of the toxic protein of the crystals is best achieved outside the insect in the artificial conditions of pure culture rearing on sterile synthetic media of definite composition. This makes it possible to exploit a latent ability of an entomogenous bacterium that in the field is limited in action by the nature and environment of its host insect. As we understand it, there was an implied question in the symposium title assigned to us — what is the possibility of using bacteria instead of chemicals to control insects? It is obvious, we think, that there are situations where bacterial pathogens can be used to advantage. No biologist looks for a universal panacea, and the present microbial insecticides will certainly not replace chemical insecticides in all cases, but there are undoubtedly situations where their use ~ presents encouraging possibilities. REFERENCES (1) Ancus, T. A. (1954). A bacterial toxin paralyzing silkworm larvae. Nature, Lond 173: 540. | | (2) Ancus, T. A. (1956). Extraction, purification, and properties of Bacillus sotto toxin. Canad. J. Microbiol. 2: 416-426. (3) Ancus, T. A. and Hermpet, A. M. (1956). An effect of Bacillus sotto on the larvae of Bombyx mori. Cana. Ent. 88: 138-139. (4) Ancus, T. A. and Hermpet, A. M. (1959). Inhibition of feeding, and blood pH changes, in Lepidopterous larvae infected with crystal-forming bacteria. Canade | Ent. 71,0392 996. (5) Aoki, K. and Cuicasaxki, Y. (1915). Ueber die Pathogenitat der sog. Sotto- Bacillen (Ishiwata) bei Seidenraupen. Mitt. Med. Fakult. Kais. Univ. Tokyo. IGz 419-440. (6) Brarp, R. L. (1945). Studies on the milky disease of Japanese beetle larvae. Conn. Agr. Expt. Sta. Bull. 497: 505-581. (7) Bucuer, G. (1959). The bacterium Coccobacillus acridiorum d’Herelle; its taxonomic position and status as a pathogen of locusts and grasshoppers. jedusect. Pathe; 351-346, (8) Bucuer, G. E. and SrepHens, J. M. (1957). A disease of grasshoppers caused by the bacterium Pseudomonas aeruginosa (Schroeter) Migula. Canad. J. Microbiol. 3: 611-625. (9) FisHer, R. and Rosner, L . (1959). Toxicology of the microbial insecticide, Thuricide. Agr. and Food Chem. 7: 686-688. Proc. ent. Soc. Ont. 90 (1959)—1960 20 (10) Hannay, C. L. (1953). Crystalline inclusions in aerobic spore-forming bacteria. Nature, Lond. 172: 1004. (11) Hannay, C. L. (1956) Inclusions in bacteria — in Bacterial Anatomy, Sixth Symp. Soc. gen. Microbiol. Cambridge Univ. Press. (12) Heimper, A. M. (1954) A strain of Bacillus cereus Fr. and Fr. pathogenic for the Larch Sawfly, Pristiphora erichsoni (Htg.). Canad. Ent. 86s 73-77. (13) Hemmpex, A. M. (1955). The pH in the gut and blood of the larch sawfly, Pristiphora erichsoniu (Htg.), and other insects with reference to the pathogenicity of Bacillus cereus. Fr. and Fr. Canad. J. Zool. 33: 99-106. (14) Hemmpet, A. M. and Ancus, T. A. (1958). Recent advances in the know- ledge of some bacterial pathogens of insects. Proc. Tenth Int. Cong. Ent. eee lt -/22. (15) Hermmper, A. M. and Ancus, T. A. (1958). The taxonomy of insect patho- gens related to Bacillus cereus Frankland and Frankland. Canad. J. Mic- robiol. 4: 531-541. (16) Hrmmpet, A. M. and Ancus, T. A. (1959). The site of action of crystal- liferous bacteria in Lepidoptera larvae. J. Insect Path. 7: 152-170 (17) D'Heretre, F. (1911). Sur une €pizootie de nature bactérienne sévissant sur les sauterelles au Mexique. C. R. Acad. Sci., Paris, 152: 1413-1415. (18) IsarwatTa, S. (1905) Sur le bacille appele “Sotto’’. Bull. de l'association seri- cole du Japan, Tokyo. (19) Marres, O. (1927). Parasitare Krankheiten der Mehlmottenlarven und Versuche uber ihre Verwendbarkeit als biologisches Bekampfungsmittel. Sitzber. Ges. Beforder. ges. Naturw. Marburg. 62: 381-417. (20) SreinHAus, E. A. (1951). Possible use of B. thuringiensis Berliner as an aid in the biological control of the alfalfa caterpillar. Hilgardia 20: 359-381. (21) Sremnnaus, E. A. (1959). On the improbability of Bacillus thuringiensis Berliner mutating to forms pathogenic for vertebrates. J. econ. Ent. 52: 506-508. (22) STEPHENS, J. M. (1952). Disease in codling moth larvae produced by several strains of Bacillus cereus. Canad. J. Zool. 30: 30-40. (23) STEPHENS, J. M. (1957). Spore coverage and persistence of Bacillus cereus Frankland and Frankland sprayed on apple trees against the codling moth. Canad. Ent. 89: 94-96. (24) Tanapa, Y. (1959). Microbial control of insect pests. Ann. Rev. Ent. 4: 277-302. (25) Youne, I. E. (1958). Chemical and morphological changes during sporula- tion in variants of Bacillus cereus. PH. D. thesis, Med. School Library, Univ. of Western Ontario, London, Canada. (26) Waite, R. T. and Durky, S. R. (1940). Effect of the introduction of milky diseases on populations of Japanese beetle larvae. J. econ. Ent. 33: 306-309. (Accepted for publication: March 3, 1960) Proc. ent. Soc. Ont. 90 (1959)—1960 21 CURRENT STATUS OF MITE-TRANSMITTED PLANT VIRUSES’ JOHN T. SLYKHUIS The only mites reported to transmit plant viruses belong to the Eriophyidae, a taxonomically distinct group that does not appear to be closely related to any of the other mites (14). The eriophyids are tiny creatures, which average about 1/5 millimeter in length. Their main distinction is the possession of only 4 legs. The genitalia are just behind the legs, and the abdomen is elongate with the surface characterized by narrow transverse rings typically bearing bead-like microtubercles. : i The eriophyids feed by sucking plant juices in a manner that appears to be well suited for the transmission of plant viruses. Their slender stylets, which rest in a groove in the rostrum, puncture plant tissue but cause little apparent damage to the plant cells. The rostrum is a jointed structure, the apex of which is a pair of pads which apparently conduct saliva to the stylets and suck up plant uices. | The developmental history of eriophyids is simple and may be completed in 6 days (34) but usually takes 10-14 days. ‘There are two nymphal instars, the second terminating in a resting period or ‘pseudopupa’ during which the genitalia form and protrude through the body wall. Males are usually smaller than females and in some species are rarely observed. Some species have two types of females, one being specialized for hibernation. Eriophyids have intimate and usually highly specific host relations. Some mites parasitize only certain species of one genus, many have hosts in several genera, but it is rare for one mite species to have hosts in more than one plant family. All are essentially parasites of perennial plants because they have no resistant forms that can survive long periods in the absence of a living host plant. Annuals do not ordinarily afford the necessary stable basis for colony founding and perpetuation, but there are exceptions in which annuals become infested by mites from perennials. Sometimes an annual favorable to the mites grows in an overlapping sequence providing suitable immature plants throughout the year; this happens with wheat in areas where Aceria tulipae Keifer is important as a vector of wheat streak mosaic virus (29). The eriophyids cannot fly, and their range of independent movement is limited by their small size and their dependence on specific hosts for food and protection from desiccation. In 1928 Massee (17) reported that black currant gall mites were transported by aphids, bees and coccinellid beetles. Although A. tulipae may also be carried to a limited extent by insects (11), wind is of primary importance in dispersing these mites in wheat fields (29). ; Eriophyids usually feed on young tissues and so are frequently found in buds and on young leaves. Most species cause no noticeable injury to their hosts, and since they are so minute their presence is usually overlooked. A minority of | species cause visible injuries that may range from leaf discolorations to varied - malformations, galls, bud blasting, etc. It is sometimes very difficult to distinguish virus symptoms from mite injury. TECHNIQUES FOR EXPERIMENTING WITH MITES AS VECTORS OF PLANT VIRUSES I am not being droll when I emphasize that the first requirement for deter- mining if a virus is transmitted by eriophyid mites is to find the mites. Even if your eyesight is perfect you will need a hand lens of at least 10 power to find them — a 20- to 40-power microscope is essential for most procedures requiring 1Contribution No. 58, Plant Research Institute, Canada Department of Agriculture, Ottawa; presented as an invitation paper at the joint meeting of the entomological societies of Ontario, Canada and America, at Detroit, Michigan, November 30 - December 3, 1959. Proc. ent. Soc. Ont. 90 (1959)—1960 22 the handling of individual mites. A convenient tool for handling either mites or eggs without injury is a single hair cemented to a handle about the size of a pencil (29). The author prefers squirrel hairs, or so-called ‘‘camel hair” from ordinary water color paint brushes, because these are tapered and the tips can be cut back to obtain the desired flexibility. Others have used human hair (6), or fine steel needles. If the leaves of the infested host plant are tightly rolled as is the case with wheat infested with Aceria tulipae, the mites can be exposed by using spring hair clips to clip the leaf flat on a microscope slide; or the leaf may be stuck flat on adhesive cellulose tape fastened with adhesive side up, on a glass slide. Other ingenious methods for examining rolled wheat leaves for mites have been described by Fellows (8). Despite their small size, eriophyids can easily be confined on potted plants. Various sizes and forms of cages can be made with clear sheet plastic, and ventilation holes can be covered satisfactorily by cementing over them white taffeta cloth made of a synthetic fibre, preferably dacron which is tolerant to water and light. Sometimes it is convenient and desirable to grow healthy seed- lings in sterilized soil in large test tubes plugged with cotton; the test tubes can also function as cages, and individual mites or eggs can be placed on the seedlings without danger of unwanted intruders (29). Because of their mobility and small size, difficulties arise in experiments that require repeated handling of individual mites. No efficient procedures have yet been reported for confining a mite on specific areas of a plant for any desired period of time, and then retrieving the same mite for further tests. It is relatively simple to prove that symptoms associated with mites are caused by a virus if the virus is transmitted efficiently by the mites, has a short incubation period in the plant, and is readily sap transmitted. Such 1s the case with wheat streak mosaic virus. The required procedures are difficult, hazardous and slow if none of these conveniences exist, as with currant reversion. Some non-sap transmissible viruses can be transmitted by grafting diseased buds or twigs onto healthy plants, but in order to prove that any of the symptoms resulting from such a procedure were caused by a virus transmitted by grafting and not by the feeding of mites, special measures are needed to ascertain that both the diseased source plants and the test plants were freed from mites before, and kept free during the entire tests. Virus symptoms can usually be differentiated from mite injury if the plants continue to produce symptoms even after freed from mites. Non-viruliferous colenies can usually be reared from mites hatched from eges transferred to healthy plants. It is then possible to compare the effects of these mites with the effects of mites reared on diseased plants, and to test for acquisition of virus by feeding the non-viruliferous mites on diseased but mite- free plants before transferring them to test plants. PLANT VIRUSES KNOWN TO BE TRANSMITTED BY MITES Six viruses are known to be transmitted by mites (Table 1). In each case the main economic host of the virus is a favoured host of the mite vector. Only Plant Viruses Transmitted by Mites “Vector Mite Other Disease Reported Vector | Transmission Currant reversion 1927 Phytoptus ribis eralt 1952 Wheat streak mosaic 1053 Aceria tulipae sap Wheat spot mosaic 1953 Aceria tulipae Fig mosaic hobo Aceria ficus eraft Peach mosaic 1955 Evriophyes insidiosus eraft Ryegrass mosaic L057 Abacarus hystrix sap Proc. ent. Soc. Ont. 90 (1959)—1960 23 one mite species is known to transmit each virus, but in one instance a mite transmits two distinct viruses. Three of the viruses affect only closely related woody perennials, the other three affect grasses in more than one genus, some of which are not perennials. Currant Reversion Currant Reversion was the first plant disease suspected to be caused by a mite-transmitted virus (2, 18). The disease is widespread in the British Isles and probably throughout Europe (33). It is called ‘reversion’ because the character of the leaves of the diseased black currants, Ribes nigrum, changes so that bushes appear to have reverted to the wild type. The most reliable diagnostic symptoms are the reduced numbers of sub-main veins and the coarsely toothed margins of the leaves (1). Other symptoms include the development of a crowded woody growth or ‘nettlehead’ from lateral buds, abnormal flower color, flower drop, and the shrivelling and dropping of immature fruit, but any of these symptoms may result from other causes so are not reliable for the diagnosis of reversion. The mite, Phytoptus ribis (Westw) Nalepa, appears always to be associated with reversion. It also causes gall-like swellings called ‘big bud’. Currant reversion virus is apparently not sap transmissible. It was readily communicated by grafting diseased shoots, or even wood without buds onto healthy bushes, but it required about 18 months for symptoms to show. Results of early experiments suggested that reversion was caused by a virus transmitted by the mite P. rzbis, but they were not conclusive (2). The relation of mites to the initiation of reversion symptoms was further demonstrated after each of 24 carefully selected normal black currant bushes, were artificially infested with black currant gall mites obtained from reverted bushes. A total of 2,400 mites were transferred to each of the inoculated plants each year for three years. All six control plants which were kept free from mites by spraying with lime sulfur and dusting with sulfur, while at the same time being kept isolated from the others, remained apparently normal throughout the experiment (18). Further investigations on currant reversion could profitably include experi- ments on the persistence of symptoms on reverted bushes freed from mites, graft transmission in the complete absence of mites, the effects of non-viruliferous mites reared from eggs hatched on healthy plants, and the acquisition of currant reversion virus by non-viruliferous mites. Despite the abundance of mites and their persistence on infested currant bushes, neither the mites nor the reversion disease appear to spread rapidly to new bushes. This is fortunate, because it enables roguing diseased plants to reduce spread. New bushes can even be safely planted where diseased ones were removed. Spraying the bushes with winter strength lime sulfur when the leaves are about an inch across and the blossom trusses are open, kills many mites at the period when most migration occurs, and so effectively reduces spread of reversion (3). | Wheat Streak Mosaic Wheat streak mosaic has been known since 1929 when it was first found in Kansas (19, 21). Later it became recognized as a cause of serious losses of wheat in Kansas and other parts of the great plains and western areas of North America (7, 16, 26, 27, 28, 34). It was first shown to be transmitted by a mite, Aceria tulipae Keifer, in Alberta, Canada in 1952 (28). As indicated earlier, wheat streak mosaic virus contrasts with the cause of currant reversion by being readily transmitted by sap inoculation, by having a short incubation period in its host (6 days or longer depending on tempera- ture), and by being efficiently transmitted by the mite vector. In addition, the Proc. ent. Soc. Ont. 90 (1959)—1960 24 mites multiply quickly on wheat, which is easily and quickly grown as a test plant. Once the mites were suspected, they were quickly proved to be a vector, and the epidemiology of the disease was soon correlated with the history of the mites in the field (29). When mites reared on diseased wheat were transferred two to each test plant, 30-70% of the test plants developed symptoms, and the presence of wheat streak mosaic virus on these was proved by sap transmission to other plants. All stages of mites except the eggs were infective. Viruliferous mites remained infective for six days on a host immune to the virus. Non-viruliferous colonies were developed from eggs hatched on wheat seedlings growing in sterilized soil in large test tubes plugged with cotton. Nymphs from these colonies became viruliferous during a 30 minute period on diseased wheat, but adults did not appear able to acquire the virus. The virus is readily tranmitted both manually and by mites to a number of graminaceous annuals, and a few perennials have proved slightly susceptible or symptomless carriers (20, 25, 27, 29, 34). Also, A. tulipae has been found on a number of perennials (5, 29). Probably a native perennial is the natural source of the disease. Wheat is the most favorable host for multiplying both the virus and the mites, and despite the fact that it is an annual, it is of predomin- ant importance in perpetuating the virus and vector throughout the year, and in building up a high level of diease in the field (29, 32, 34). Winter wheat infected with mites in the fall harbors them and the virus over winter. The next spring and summer the mites multiply and are dispersed by wind. Any immature spring or volunteer wheat, or shoots from hailed crops, can perpetu- ate the virus and mites after the winter wheat crop matures and so may provide sources of infection for fall-sown crops. A break in the continuity of immature wheat practically eliminates the disease, therefore it is not a problem in spring wheat areas where no winter wheat is grown to harbor the vector and virus over winter, or in other wheat growing areas where for one reason or another immature wheat is absent during the summer. Wheat streak mosaic can spread with surprising rapidity into new crops from adjacent sources, and can cause spectacular destruction: but the effective- ness of simple control measures can be just as spectacular. The key to control is an interruption of the continuity of immature wheat. In southern Alberta this is achieved by not planting winter wheat until early or mid September, or after all wheat crops in the area have matured, and by eliminating all immature wheat in the vicinity a week or more before seeding (29, 33). Similar precautions are also effective in Nebraska (34), but the conditions necessary for control are sometimes difficult to achieve in Kansas where the fall season is often long, -warm, and favorable to continued growth of volunteer wheat and for the multiplication and spread of mites (16). Mosaic tolerant varieties have assisted in reducing losses from the disease. Miticides have been tested but none have proved sufficiently effective for practical control of the disease (13). Wheat Spot Mosaic Wheat spot mosaic virus was detected when A. tulipae was proved a vector of wheat streak mosaic virus and has been reported only in Alberta (28, 30). When mites from naturally diseased wheat were tested singly on individual test plants, some of the plants, instead of developing streak symptoms, developed chlorotic spots, severe chlorosis, stunting and necrosis, but no sap-transmissible virus could be detected. The symptoms continued to develop even after the plants were freed from mites. The possibility of a toxin or feeding injury was dismissed after it was also found that when eggs from mites that produced such symptoms were hatched on healthy wheat, the subsequent mites and their progeny did not induce the symptoms unless they were first colonized on Proc. ent. Soc. Ont. 90 (1959)—1960 25 diseased plants. The symptoms were therefore attributed to a virus. Different isolates differed in severity, some caused extreme chlorosis and killed the plants quickly. Unpublished results have shown that a single mite can simultaneously carry both wheat streak and wheat spot mosaic viruses. Plants infected with both became more severely diseased than plants infected with either virus alone. Since A. tulipae is the vector of both viruses, the epidemiology and control of wheat spot mosaic are the same as for wheat streak mosaic. Fig Mosaic Fig mosaic virus was the first tree virus shown to be transmitted by mites (9, 10). The disease has been reported in widespread locations including the British Isles, New South Wales, and Italy as well as California (4, 12, 33). The symptoms include varying chlorotic mosaic patterns and leaf distortion. The symptoms of mosaic are sometimes confused with leaf spotting, chlorosis and russetting caused by the fig mite, Aceria ficus (Cotte). Fig mosaic was described as a virus disease in California by Condit and Horne (4) who also suspected the fig mite as vector. It was demonstrated that healthy fig seedlings developed symptoms as a result of placing mite-infested leaves and bud scales on them. Evidence that the disease was caused by a virus rested on graft transmission experiments, but precautions were not taken to ascertain that mites were not present and therefore not a direct cause of symptoms. Proof that fig mosaic was caused by a virus transmitted by A. ficus was reported by Flock and Wallace (9). They found that mosaic symptoms continued to develop on fig cuttings dusted with sulfur to kill the mites, and grown in a mite-free environment. Graft transmission was successful in the complete absence of mites. Mite transmission was proved by transferring | to 200 mites from diseased trees to healthy test seedlings, then after 3-5 days, killing the mites with sulfur. Some mosaic-like symptoms developed in less than 10 days, but similar symptoms were also caused by non-viruliferouse mites from eggs hatched on disease-free seedlings. The mosaic symptoms required 10 or more days to appear. In tests with one viruliferous mite per test plant, 7 out of 10 plants developed mosaic symptoms and if higher numbers were put on each plant nearly all plants became infected. With such an efficient and abundant vector, and the host being a perennial, it is not surprising that fig mosaic appears to have infected all field-grown fig trees in California (9). It is not know how much damage the disease causes to fig production, or whether practical control can be achieved. Peach Mosaic Peach mosaic virus was also reported to be transmitted by a mite in 1955 (35). The mite was later named Eriophyes insidiosus Keifer and Wilson (15). Both the disease and the mite are common in California and have been observed in Colorado, Arizona and New Mexico. Vectors of the disease were sought for many years, but successful trans- mission with mites did not come until after more than 8,000 tests with more than 150 species of insects and other mites. Eriophyes insidiosus found in buds of diseased peach and plum trees were transferred, in varying numbers to the buds of 65 young potted peach seedlings. Seventeen of the seedlings developed symptoms in 14 to 100 days, and the presence of the mosaic virus was confirmed by patch bark graft transmission to other healthy seedlings. Check plants that had received equivalent numbers of E. insidiosus mites from healthy peach and plum did not develop symptoms. Proc. ent. Soc. Ont. 90 (1959)—1960 26 In later experiments reported by L. S. Jones in a personal communication, 50 mites from buds of diseased trees transferred to each of 25 test plants induced peach mosaic in 18 plants or 72%. Fewer transmissions resulted when fewer mites were used. With one mite to each of 80 test plants, two plants or 2.5% developed symptoms. Mites from eggs hatched on healthy seedlings did not cause mosaic symptoms on test plants. Infective mites retained the ability to transmit virus for at least two days on glass slides in the absence of a virus source. Not all susceptible peach and plum trees are diseased in the field so it appears that peach mosaic is not spread as readily as fig mosaic. It is not known what losses are caused by the disease, and practical control measures have not been devised. Ryegrass Mosaic Ryegrass mosaic is caused by a sap-transmissible virus that was first isolated from perennial ryegrass (Lolium perenne L.) and Italian ryegrass (L. multi- florum Lam.) in Britain in 1956. It was later found common in six countries on the continent of Europe (31). The symptoms include green to yellow mottling and streaking of the ryegrass leaves. Some virus isolates affect some strains of ryegrass severely causing a brownish necrosis of leaves and reduced growth and vigour of the plants. Oats, rice, cocksfoot, and meadow fescue have been infected with the virus by sap inoculation. Transmission of the virus was achieved with erlophyid mites which were common on ryegrass. Mulligan (22) found that of the three species found on ryegrass, only Abacarus hystrix (Nalepa) transmitted the virus. When reared on diseased ryegrass, all stages of the mites, but not the eggs, proved viruliferous. Mites remained infective up to 12 hours while on wheat, which is immune to the virus. Non-infective mites, from eggs hatched on healthy plants, acquired the virus during a two hour feed on diseased ryegrass. : Perennial ryegrass appears to provide the main widespread, permanent reservoir of both virus and vector. Although some plants are so susceptible they die out, and many others, even in old stands, appear to be virus free, plants with mild symptoms are common. Susceptible strains of Italian ryegrass, a biennial, have been found heavily infected early in the second year, indicating that the virus had spread into the planting extensively the first summer. It does not appear feasible to attempt to control this disease either with miticides, as used for currant reversion, or by cultural practices, as used for wheat streak mosaic; but since there are such wide variations in the reactions of both perennial and Italian ryegrass plants, it appears desirable for plant breeders to select strains of these grasses resistant or immune to the virus. VIRUSES SUSPECTED TO BE TRANSMITTED BY MITES An infestious degeneration of vines in Germany has been reported to be caused by a sap transmissible virus which was also transmitted by mites (Eriophyes vitis), four species of aphids, a number of root attacking nematodes, and also by a dodder, Cuscuta campestris, (23, 24). This is exceptional in that no other mite-transmitted virus has been proved transmitted by other vectors, and only two, wheat streak mosaic and ryegrass mosaic viruses are known to be Sap transmissible. It is desirable that further experimental details be docu- mented to clarify this phenomenon. Agroypron mosaic, caused by a sap transmissible virus, has been found on Agropyron repens, in several diverse locations in North America (19, 27). In Ontario it also causes mosaic symptoms including chlorotic streaks on wheat, and in several respects resembles wheat streak mosaic. Infection has resulted Proc. ent, Soc. Ont. 90 (1959)—1960 2/7 when wheat seedlings, growing in pots covered with cages made of 72 mesh per inch screen, were left in the field near naturally diseased A. repens or wheat for a few days. Eriophyid mites are always present when natural infection occurs. Two species, Abacarus hystrix (Nal) and Vasates mckenziei (K) are common on A. repens. These two species and also Aceria tulipae have all been found on wheat in Ontario. Although A. tulipae found in Ontario can transmit wheat streak mosaic virus, it failed to transmit Agropyron mosaic virus. SUMMARY AND CONCLUSIONS The only mites known to transmit plant viruses are Eriophyidae. These four legged, usually worm-like mites feed with delicate piercing and sucking mouthparts that cause little immediate damage to the cells of the tissues on which they feed. Few eriophyids cause noticeable damage to their hosts. They cannot survive more than a few days absent from their specific hosts, conse- quently their hosts are principally perennials, or more rarely annuals that grow in an overlapping sequence suitable to harboring the mites through all seasons of the year. Of the six viruses known to be transmitted by mites, only two, wheat streak mosaic and ryegrass mosaic viruses, are sap transmissible. Wheat streak mosaic and wheat spot mosaic viruses are transmitted by the same mite, and although they probably originated on perennial grasses they are of major importance on wheat which is an annual. All the other mite transmitted viruses cause diseases of perennials and are each transmitted by a different mite species. Highly effective control of wheat streak mosaic and wheat spot mosaic can be achieved by elminating immature wheat that could harbor the mites and viruses before winter wheat is planted in the vicinity, thus interrupting the continuous sequence of wheat which is necessary to perpetuate the disease. Currant reversion, which is spread slowly by the black currant gall mite, can be held in check by replacing diseased bushes, and by using miticides. Since the hosts are perennials and the mites efficient vectors, it appears difficult to develop cultural or chemical contro] for the mite-transmitted fig mosaic, peach mosaic and ryegrass mosaic diseases. It should be possible to select strains of ryegrass highly resistant to ryegrass mosaic. LITERATURE-€LTED (1) Amos, J. and Harron, R. G. (1927). Reversion of black currants. I. Symp- toms and diagnosis of the disease. J. Pom. and Hort. Sci. 6: 167. (2) Amos, J., Hatron, R. G., Knicur, R. C. and Masser, A. M. (1927). Experi- ments in the transmission of reversion in black currants. Rep. East Malling Res. Sta. for 1925. II. Suppl. 126. (3) Amos, J., Hatton, R. G., Knicnt, R. C. and Masser, A. M. (1927). “Rever- sion” in black currants: Its cause and eradication. Kent Cherry and Fruit Show Catalogue. July 15. (4) Conpit, I. J. and Horne, W. T. (1933). A mosaic of fig in California. Phytopathology 23: 887. (5) Connin, R. V. (1956). The host range of the wheat curl mite, vector of wheat streak mosaic. J. econ. Ent. 49: 1. (6) Det Rosario, M. S. and Stitt, W. H. Jr. (1958). A method of rearing large colonies of an eriophyid mite, Aceria tulipae (Keifer) in pure culture from single eggs or adults. J. Econ. Ent. 57: 303. Proc. ent. Soc. Ont. 90 (1959)—1960 28 (7) Fettows, H. (1949). A survey of the wheat mosaic disease in western Kansas. Mant Dis: Reptirny 33:30: (8) Frtitows, H. (1956). Mechanical aids in the study of eriophyid mites in relation to yellow streak mosaic of wheat. Plant Dis. Reptr. 40: 601. (9) Bwock, R: A.and WALLACE, ‘J. M. (1955). Transmission of fig mosaic by the eriophyid mite Aceria ficus. Phytopathology 45: 52. (10) Frock, R. A. and Wattace, J. M. (1956). Fig mosaic transmitted by mite. GalitoAcric. 11.12. (11) Grsson, W. W. and Painter, R. H. (1957). Transportation by aphids of the wheat curl mite, Aceria tulipae (K), a vector of the wheat streak mosaic wars. |. Kans: ent. Soc. 30: 147. (12) Graniti, A. (1954). Fig mosaic in Italy and its probable vectors. (In Miialian). Riv. Prutticolt..16:-23..(Abstr. R-A.M. 34: 735.) (13) Kanrack, E. J. and Knutson, H. (1958). Chemical control studies on the wheat curl mite. J. econ. Ent. 51: 68. (14) Kerrer, H. H. (1952). The eriophyid mites of California. Bull. Calif. fpsect Survey, 2, No. I. (15) Kerrer, H. H. and Wirson, N. S. (1956). A new species of eriophyid mite responsible for the vection of peach mosaic virus. Bull. Calif. Dept. Agric. fis, 15: (16) Kine, C. L. and Siri, W. H. Tr. (1959). 1959 wheat streak mosaic epiphy- totic in Kansas. Plant Dis. Reptr. 43: 1256. (17) Masser, A. M. (1928). The life-history of the black currant gall mite, Eriophyes ribis (Westw.) Nal. Bull. ent. Res. 18: 297. (18) Masser, A. M. (1952). ‘Pransmission of reversion of black currants. Ann. Rept. East Malling Res. Sta. for 1951. 162. (19) McKinney, H. H. (1937). Mosaic diseases of wheat and related cereals. eS Pept Aor Circ. No. 442. (20) McKinney, H. H. and Feitows, H. (1951). Wild and forage grasses found to be susceptible to the wheat streak-mosaic virus. Plant Dis. Reptr. 35: 44. (21) MELCHERS, L. E. and Fettows, H. (1930). Wheat mosaic in Kansas. Plant Diss dkepir, 17: 158. (22) Mutuican, T. (1959). The transmission by mites, host range and properties of ryegrass mosaic. Unpublished report for Rothamsted Experimental Station. (23) Ocus, G. (1958). Concerning three viruses as agents of vine diseases (In German). Z. Pflkrankh. 65: 11. (24) Ocus, G. (1958). Studies on the spread of vine viruses by vectors. (In German). Naturwissenschaften 45: 193. (25) Sint, W. H. Jr. and Connin, R. V. (1953). Summary of the known host range of the wheat streak-mosaic virus. Trans. Kans. Acad. Sci. 56: 411. (26) Stitt, W. H., Fettows, H. and Kine, C. L. (1955). Kansas wheat mosaic situation 1953-54). Plant Dis. Reptr. 39: 29. Proc. ent. Soc. Ont. 90 (1959)—1960 29 (27) Stykuuis, J. T. (1952). Virus diseases of cereal crops in South Dakota. South Dakota Agr. Expt. Sta. Tech. Bull. 11. (28) StyKuurs, J. T. (1953). Wheat streak mosaic in Alberta and factors related — to its spread. Canad. J. Agr. Sci. 33: 195. (29) Stykunuis, J. T. (1955). Aceria tulipae Keifer (Acarina: Eriophyidae) in relation to the spread of wheat streak mosaic. Phytopathology 45: 116. (30) StykHuis, J. IT. (1956). Wheat spot mosaic, caused by a mite-transmitted virus associated with wheat streak mosaic. Phytopathology 46: 682. (31) Stykuuis, J. T. (1958). A survey of virus diseases of grasses in northern “Europe: A-O. Plant Prot Bull sozmii29) (32) Stykuuis, J. T., ANpREws, J. E. and Pirrman, U. J. (1957). Relation of date of seeding winter wheat in southern Alberta to losses from wheat streak mosaic, root rot and rust. Canad. J. Plant Sci. 37: 113. (33) SmiruH, K. M. (1957). A textbook of plant virus diseases. 2nd ed., Churchill, Lond. (34) StapLes, R. and ALLINGTON, W. B. (1956). Streak mosaic of wheat in Nebraska and its control. Nebraska Agr. Expt. Sta. Res. Bull. 178. (35) Wixson, N. S., Jones, L. S. and Cocuran, L. C. (1955). An eriophyid mite vector of the peach mosaic virus. Plant Dis. Reptr. 39: 889. (Accepted for publication: March 7, 1960) NEW DISTRIBUTION AND HOST RECORDS FOR BAT FLIES, AND A KEY TO THE NORTH AMERICAN SPECIES OF BASILIA_ RIBEIRO (DIPTERA: NYCTERIBIIDAE)’ B. V. .PETERSON’ The most recent and complete account of nycteribiid distribution in North America is that by Guimaraes and d’Andretta (8). During the past few years, the author has accumulated a small number of nycteribiids, most of which represent new distributions or provide new host records. Specimens in the collections of a number of North American institutions, which were made available to the author for study, also provided a number of unpublished records. Since the known distribution of North American species is limited, it seems worthwhile to present these additional records. The presence of Basilia forcipata Ferris in Oregon, Montana, Washington, and British Columbia, extends marked- ly the northward distribution of the family in North America. Specimens from British Columbia provide the first records of the family in Canada. A key for the determination of the females of the new world species was given by Guimaraes and d’Andretta (8). However, to the author’s knowledge, a key for the determination of the males of North American species has never iNorth America, as used in this paper, refers to that part of the continent north of Mexico. 2Entomology Laboratory, Research Branch, Canada Department of Agriculture, Guelph, Ontario. Proc. ent. Soc. Ont. 90 (1959)—1960 30 been presented. All the known North American species of Nycteribiidae belong in the genus Basilia Ribeiro, and keys for the determination of both females and males are presented below. The key to the males, however, must be consid- ered tentative until a larger number of specimens are available for study. Basilia myotis Curran has not been reported to occur north of Guatemala but is in- cluded in the keys since it is probably a matter of time until this species will be found in the southwest regions of the United States. The terminology used in the keys is, with minor exception, that of Theodor and Moscona (15). It should be noted that, in both the male and the female, abdominal sternites | and 2 have fused to form the plate which bears the abdominal ctenidium, and this plate should be considered as sternites 1 and 2 when using the keys. KEY TO THE NORTH AMERICAN SPECIES OF BASILIA Females 1. Posterior margin of mesonotum with a prolonged, upright, finger-like (SUOESE CBG GE SINC Aes elaine nan De, aren oe earns Ane eee eter ss en meer eate ree Posterior margin of mesonotum without a prolonged, upright, finger-like “SS ESEGS ca yelc cau level eer nN a ea ee ECP eR Tp ce cr 3 2. Posterior margin of the large tergite (tergite 2) occupying the middle of the abdomen with two short, broad, distinct lobes which are separated by a broad notch; each lobe with a tuft of short, stout setae on the medial edge, and longer and more slender setae on the lateral edge. The posterior margin of the preceding small tergite (tergite 1) with two medial tufts of long setae which extend posteriorly to about the middle of the large tergite (figs Be errs re ose a AS boardmani Rozeboom, 1934. Posterior margin of the large tergite (tergite 2) occupying the middle of the abdomen with two very short, rounded lobes which are separated by a small, shallow notch; each rounded lobe with a tuft of long setae intermixed with a few, much shorter setae. The posterior margin of the preceding small Lekites (terete l\owith short setae only. (figs. 3, 4) 2.00.05 2s. rere Mca Ie oaks POE il rondanii Guimaraes and d’Andretta, 1956. Pe OeaiMem withic 2. vistle:tergites <2 a ee. 4 Poe d@ilen wnt) 5 MASIDIe CETOltES ic oa te a ON ele ceca 5 4. Posterior margin of large median tergite produced posteriorly as two long, slender, clavate lobes; this tergite with hairs toward the middle (figs. 5, 6) ee) ee ae corynorhini (Ferris), 1916. Posterior margin of large median tergite not produced into lobes; this tergite without hairs except toward the sides (figs. 7, 8).........0.000005: ee shee Saas ars: 5. Large median tergite composed of a single piece which is more or less emarginate in the middle along posterior margin. Sternite 6 not longitudin- ally divided on the midline. Anal segment divided into two short, but conspicuous, slender lobes each of which bears a series of stout setae (figs. Uy WUD ACLS ent Seen soe tees See ec aie nec eer OMe An ee tie forcipata Ferris, 1924. Large median tergite divided in the middle. Sternite 6 longitudinally divided on the midline. Anal segment divided into two very short lobes, each of Euinelbeatseasenics of stout setae : (lies 12913, 14) oe eel. antrozot (Townsend), 1893. Proc. ent. Soc. Ont. 90 (1959)—1960 Males 1. Posterior margin of sternite Z with about 14-20 short spines in one or {WO TOWS- Saag ee eee eee ee 2 Posterior margin of sternite 5 with about. 23-38 short spines in one to three rows;;,one: row: of, which-181ong 0) eee 2 4 Clasper slender, tapering to a rather fine point, tip not bending inwardly. Terminal abdominal segment conspicuously longer than wide at base; dorsal surface with short, stout, erect, spine-like setae and two or three long setae on posterolateral angles; ventrolateral margins lightly setose. Sternite 5 relatively long; posterior margin rounded with a slight medial convexity, bearing about 18 spines in two short, irregular rows .. corynorhint. Clasper broader, tapering but apex more bluntly pointed, tip bending inwardly. Terminal abdominal segment variable; dorsal surface with mixture of long and short setae; ventrolateral margins moderately or heavily setose. Sternite 5 relatively short; posterior margin rounded but with a conspicuous convexity or a small, median notch; bearing one or two rows Of SPINES 28.4) Nive se es a eee oa coe ee 3 Tergites 5 and 6 with setae only on their hind margins; tergites 2-4 with additional scattered small setae. Ventrolateral margins of terminal segment — moderately setose. Sternite 5 with a short, broad, convexity which is notched on the midline; with a relatively long, irregular row of about 14-18 spines (sometimes the spines are in a single, irregular row and sometimes a short second row of spines is present). Tibiae only moderately broad .. fore:pata. Tergites 3-6 with setae only on their hind margins. Ventrolateral margins of terminal segment heavily setose. Sternite 5 only slightly rounded on the hind margin and with only a small shallow notch on the midline; with about 15-20 spines in two short, irregular rows. Tibiae very broad....myotis. Hind margin of sternite 5 straight or slightly rounded, with a moderately broad, median, shallow concavity; with about 24-30 short spines in two relatively long, irregular rows. Ventrolateral margins of terminal segment moderately setose. Tergites 5 and 6 with setae only on their hind margins; tergites 2-4 with additional scattered, small setae. Tibiae slender, somewhat spindle-shaped i005. sais sascha see eee ree ee ints ONEVOLOE Hind margin of sternite 5 rounded with a small notch on the midline; number of spines variable. Ventrolateral margins of terminal segment densely setose. lergal: setae variable. “Vibtae broader...) 22 ee 5 Hind margin of sternite 5 with a long, irregular series of about 38 spines placed in two or three rows; tergites 3-6 with setae only on their hind mareims. Vibiae. very broad: i tay see a rondanit. Hind margin of sternite 5 with a long, very irregular series of about 23-34 spines. Tergite 6, and sometimes 5, with setae only on the posterior margin, at least tergites 2-4 with additional scattered small setae. Tibiae only moderately: abroad 4525 he saa eee ay boardmani. DISTRIBUTION Basilia antrozoi (Townsend) New records. Arizona. Cochise Co.; Southwest Research Station (A.M.N.H.), June 29, 1958, M. A. Cazier, ex ‘Avipobous pallidus — 1%, 499. Willcox, August 4, 1909, A. K. Fisher, ex Antrozous sp. — 19. Proc. ent. Soc. Ont. 90 (1959)—-1960 32 Oklahoma. Cimarron Co.; Pigeon Cave, three miles east, one mile north Kenton, V. H. Zeve, ex Antrozous pallidus — 9¢¢, 2099. Oregon. Con Canyon, July 20, 1939, J. Savage, ex Antrozous pallidus — 19. Utah. Grand Co.; Dewey Bridge, Colorado River, May 14, 1954, B. V. Peterson, ex Antrozous pallidus — 1g, 499. Washington Co.; St. George — 19. Utah (presumably near Salt Lake City, Salt Lake County), K. R. Kelson, ex Antrozous pallidus — 399. Published records. California* — 399; Kansas* — 1, 19; Louisiana* — 14, 19; New Mexico® — 1g; Texas* — 14, 299. 14, 299 from Mexico were also examined. Total num- ber of specimens examined — 16/4, 4399. Basilia boardmani Rozeboom New records. Georgia. Thomas Co.; April 29, 1947, H. B. Morlan, ex Myotis lucifugus’ — bss 1Q- Published records. Florida* — 4¢%, 699; Illinois’ — 1¥. Total number of specimens examined — 64:4, 799. Basilia corynorhini (Ferris) New records. ; Oklahoma. Greer Co.; Reed cave system, Reed, August 4, 1955, Ward, ex Plecotus rafinesquii — 19. Utah. Grand Co.; Dewey Bridge, Colorado River, May 14, 1954, B. V. Peterson, ex Pipistrellus hesperus' — 19. Published records. : California® — 1%, 19; Texas * — 1J. Total number of specimens examined — 244, 399. Basilia forcipata Ferris New records. Arizona. Yavapai Co.; Yarnell, June 5, 1936, R. Komarek, on bat — 19. Montana. Lake Co.; Yellow Bay, Flathead Lake, July 1, 1949, L. T. Nielsen, ex Myotis evotis' — 299. Oregon. Harney Co.; Malheur Lake, May 22, 1934, Bishopp, ex Myotis yuman- ensis' — 19. Wallowa Co.; Wallowa Lake, August 14, 1932, Bishopp, Myotis Spee 1! Wiah. Cache Co.; Logan Cave, Feb. 22, 1953, ex Myotis sp.— 1%. Sevier Co.; Fish Lake, July 23, 1957, J. W. Twente, ex Myotis lucifugus' — 1g. Wayne Co.; Bicknell, May 19, 1956, A. W. Grundmann, ex Myotis ywmanensis — 25 409. Weber Co.; September 16, 1950, P. Newey, ex Myotis lucifugus = 5 | Washington. San Juan Co.; Blakely Island, June 23, 1940, W. W. Dalquest, ex Myotis californicus — 1¢. Skagit Co.; Cypress Island, July 4, 1939, W. W. Dalquest, ex Myotis californicus — 19. 3Specimens examined by the author from one or more localities in the states indicated. *New host records. Proc. ent. Soc. Ont. 90 (1959)—1960 ° 3D British Columbia. Vancouver, October 1, 1940, I. McT. Cowan, ex Myotis yumanensis — 1%. Vancouver, October 18, 1940, I. McT. Cowan, ex Myotis yumanensis — 19. Vancouver, March 27, 1947, G. J. Spencer,~ex Myotis yumanensis — 2¢\%. Vancouver, October 28, 1949, G. J. Spencer, ex Myotis yumanensis — 19. Vancouver, June 8, 1956, G. J. Spencer, ex Myotis yuman- ensis — 1%. Summerland, August 5, 1951, D. Chant, ex Myotis evotis — 19. Summerland, September 4, 1943, J. A. Munro, ex Myotis lucifugus — 12, 209. Osoyoos, May 22-26, 1941, I. McT. Cowan, ex Myotis lucifugus — 124, 209. Okanagan Landing, July 29, 1941, A. Brooks, ex Myotis lucifugus — 19. Vernon, September 30, 1941, I. McT. Cowan, ex Myotis lucifugus — 19. Oyama, August 6, 1947, J. Yarwood, ex Myotis lucifugus — 1g, 19. Duncan, July, 1939, I. McT. Cowan, ex Myotis lucifugus — 12. Published records. California® — 14, 299; Colorado*’ — 14,19 (Basilia calverti, paratypes); Louis- iana* — 19; New Mexico*® — 299. Total number of specimens examined — 16/4, 2699. Basilia rondanii Guimaraes and d’Andretta Published records. Texas. 2¢\¥, 499, paratypes, from Guatemala were examined. Basilia myotis Curran. 3d ¢; 292 from British Guiana were examined. OTHER BAT, PARASITES Among the nycteribiids examined from three species of bats were a few other ectoparasitic arthropods. Records of these parasites are presented below to provide additional information on their geographic and host distributions. Pallid bat. Antrozous pallidus (Le Conte) Dewey Bridge, Colorado River, Grand Co., Utah, May 14, 1954, B. V. Peterson Bat bug, Cimex pilosellus (Horvath) (Cimicidae) Bat flea, Myodopsylla gentilis Jordan and Rothschild (Ischnopsyllidae) Southwest Research Station, (A.M.N.H.), Cochise Co., Arizona, June 29, 1958, M. A. Cazier Tick, Ornithodoros sp., larva (Argasidae) Mite, Eubrachylaelaps debilis Jameson (Laelaptidae) (this mite is commonly found on cricetine rodents and has been found on a few birds although the latter association was probably accidental. The occurrence of this mite on a bat was probably accidental also). Long-eared Myotis, Myotis evotis (Allen) Yellow Bay, Flathead Lake, Lake Co., Montana, July 1, 1949, L. T. Nielsen, Mite, Ichoronyssus sp. nr. granulosus Kolenati (Dermanyssidae). Yuma Myotis, Myotis yumanensis (Allen) Bicknell, Wayne Co., Utah, May 19, 1956, A. W. Grundmann. Bat flea, Myodopsylla gentilis Tick, Dermacentor andersoni Stiles, nymph (Ixodidae) (possibly an acciden- tal occurrence). Beetle larva, ?Cephaloscymnus sp. (Coccinellidae) (this larva is undoubtedly not a parasite, and its presence on the bat was most likely a case of accidental phorsey). Proc. ent. Soc. Ont. 90 (1959)—1960 34 allt o * ete AY AEs hay { ys s} } ri LPs, A Sa Vale / Wis, ye “ip Bz wa s- if y / 2 é = . + zi a: _ 7 Rea Mee Ue eae ee < Pe eee 7p aa So HO foe, Seem i Aes CTE SS Sit nae ee ee Le ee ote = fi 1 rh 4 E N 1 2 <, x \ 5 Explanation of Figures Figures 1-16, females. Basilia boardmani, Fig. 1. Abdomen, dorsal; Fig. 2. Abdomen, ventral. Basilia rondanii, Fig. 3. Abdomen, dorsal; Fig. 4. Abdomen, ventral. Basilia corynorhini, Fig. 5. Abdomen, dorsal; Fig. 6. Abdomen, ventral. Basilia myotis, Fig. 7. Abdomen, dorsal; Fig. 8. Abdomen, ventral. Basilia forcipata, Fig. 9. Abdomen, dorsal; Fig. 10. Abdomen, ventral; Fig. 11. Anal segment. Basilia antrozoi, Fig. 12. Abdomen, dorsal; Fig. 13. Abdomen, ventral; Fig. 14. Anal segment. Basilia boardmani, Fig. 15. Upright finger-like process of posterior margin of mesonotum. Basilia rondanii, Fig. 16. Upright finger-like process of posterior margin of mesonotum. (All figures taken from Guimaraes and d’Andretta, 1956). Proc. ent. Soc. Ont. 90 (1959)—1960 3D fis Wy An 4 st ae? Th Hea ae i yy ay ae vee 3 Tp wit \ \ at a a Sil ie Ae nd vwwit / ee ape aw ACKNOWLEDGMENTS The author extends his thanks to the following individuals who generously allowed him to examine specimens under their direction and for the free use of their records: Alan Stone, Insect Identification and Parasite Introduction Research Branch, United States Department of Agriculture, Washington, D.C.; Rupert L. Wenzel, Curator of Insects, Chicago Natural History Museum, Chicago, Illinois; Richard B. Eads, Director, Entomology Section, State of Texas Depart- ment of Health, Austin, Texas; Ira L. Wiggins, Director, Natural History Museum, Stanford University, Stanford, California; Paul W. Parmalee, Curator of Zoology, Illinois State Museum, Springfield, Illinois; Victor H. Zeve, Depart- ment of Entomology, Oklahoma State University, Stillwater, Oklahoma; and G. J. Spencer, Department of Zoology, University of British Columbia, Vancou- ver, British Columbia. I am grateful to the following specialists in the taxonomy of the various groups of arthropods who kindly confirmed or made identifications for the author: Glen M. Kohls (Argasidae and Ixodidae), Department of Health, Education, and Welfare, Public Health Service, Rocky Mountain Laboratory, Hamilton, Montana; Conrad E. Yunker (Laelaptidae and Dermanyssidae), Entomology Research Institute, Research Branch, Canada Department of Agri- culture, Ottawa, Ontario; William H. Anderson (Coccinellidae), Insect Identifi- cation and Parasite Introduction Research Branch, United States Department of Agriculture, Washington, D.C.; and George P. Holland (Ischnopsyllidae), Director, Entomology Research Institute, Research Branch, Canada Department of Agriculture, Ottawa, Ontario. SELECTED BIBLIOGRAPHY (1) Coxuins, B. J. (1931). The confused nomenclature of Nycteribia Latreille, 1796, and Spinturnix Heyden, 1826. Nat. Inst. Hlth. Bull. 155: 743-765. (2) Curran, C. H. (1935). New species of Nycteribiidae and Streblidae (Diptera). Amer. Mus. Novit. 765: 1-15. (3) Eaps, R. B. and Menzirs, G. C. (1948). Additional records of bat parasites of the Family Nycteribiidae. Ent. News 59: 244. (4) Ferris, G. F. (1916). Some ectoparasites of bats (Dipt.). Ent. News 27: 433-438. (5) Ferris, G. F. (1924). The New World Nycteribiidae (Diptera Pupipara). Ent.7News’ 35:, 191-199: (6) Ferris, G. F. (1930). The puparium of Basilia corynorhini (Ferris) (Dip- tera: Nycteribiidae). Ent. News 41: 295-297. (7) Fox, R. M. and Srasier, R. M. (1953). Basilia calverti n. sp. (Diptera: Nycteribiidae) from the interior long-legged bat. J. Parasit. 39: 22-27. (8) GuimaraEs, L. R. and d’AnpreTTA, M. A. V. (1956). Sinopse dos Nycteribi- idae (Diptera) do Novo Mundo. Arq. Zool. S. Paulo 10: 1-184. (9) PaRMALEE, P. W . (1955). A nycteribiid fly new to Illinois. J. Parasit. 71: rae (10) RozEBoom, L. E. (1934). A new nycteribiid from Florida. J. Parasit. 20: 315-316. Proc. ent. Soc. Ont. 90 (1959)—1960 36 (11) Smirn, H. M. (1934). Notes on some bat-flies of southern. Kansas and northern Oklahoma, J. Kans. ent. Soc. 7: 62-64. (12) Sprtser, P. (1907). Check-list of North American Diptera Pupipara. Ent. News 18: 103-105. (13) SraBLer, R. M. and Fox, R. M: (1952). A new nycteribiid (Diptera) from a Colorado bat. J. Colo.-Wyo., Acad. Sci. 4: 102. (14) Strives, C. W. and Notan, M. O. (1931). Key catalogue of parasites reported for Chiroptera (Bats) with their possible public health importance. Nat. inst Eilth. Bull: 155: 603-742. (15) THEopor, O. and Moscona, A> (1954).On bat parasites in Palestine. I. Nycteribiidae, Streblidae, Hemiptera, Siphonaptera. Parasitology 44: 157- ZO: (16) Townsenp, C. H. T. (1893). A nycteribid from a New Mexico bat. J. N.Y. — ene: Soc: f; 79-80. (Accepted for publication: March 15, 1960) CANADA -UNITED STATES COOPERATION IN SURVEYS AND CONTROL OF PLANT PESTS AND DISEASES’ L. L. REED Over a period of nearly fifty years the Plant Protection Division of the Canada Department of Agriculture, and similar units of the United States Department of Agriculture and of certain individual states, have co-operated in surveys and control measures associated with plant pest and disease problems of mutual interest. Many, if not mest, of these pests and diseases have been intro- duced from Europe and Asia and reached the United States first, became established, and reached Canada by normal spread or were transported on adopted hosts. In view of these circumstances, extensive research work was conducted in the United States on survey methods, including the development of special devices to supplement visual efflaminations. As the pest or disease involved reached Canadian territory through various means, the information obtained through such investigative work was made readily available to officials of the Plant Protection Division. In view of the above, the greater part of the co-operation has been provided by the United States for which we have been most grateful, but in some cases we have been in a position to reriprocate. Several instances of such co-operation are as follows: ]. Early in the twentieth century, the brown-tail moth, Nygmia phaeorrhoea (Donoy.) introduced into the United States some years earlier, was found in several sections of the Maritime Provinces of Canada. ; 1Contribution No. 129, Plant Protection Division, Production and Marketing Branch, Department of Agriculture, Ottawa, Canada; presented as part of a symposium on control, extension, and regulatory entomology, at the joint meetings of the entomological societies of America, Canada and Ontario, Detroit, Michigan, November 30- December 3, 1959. Proc. ent. Soc. Ont. 90 (1959)—1960 OM Discussions were held by officials of both countries relating to survey methods and information was freely exchanged. In biological control work, Canadian officers were assigned for periods of varying length over a number of years to assist at the Melrose Highlands, Massachusetts, Federal Parasite Laboratory in the propagation of parasites for liberation in Canada. With the gradual spread of the gypsy moth, Porthetria dispar (L.), north- ward and westward toward the Province of Quebec during the second and third decades of the present century and the establishment of the barrier zone in the Hudson River - Lake Champlain Valleys, guidance in organizing surveys in the Province of Quebec was provided by the U.S. federal authorities as well as by those of the State of New York. Following the discovery of an established infestation in Quebec in 1924, equipment and supervisory personnel were assigned by the U.S.D.A. to assist with control measures and Canadian personnel were loaned for spray operations at infestations in adjacent American territory. Similar co-operative work was carried on in southwestern New Brunswick and adjacent areas of eastern Maine between 1937 and 1940 when several small outbreaks of the gypsy moth were discovered and eradicated. In recent years, sex attractant traps, developed by the U.S.D.A., have been made available to the Plant Protection Division annually for use in border areas of eastern Canada. Male moths have been captured at a number of points in Quebec adjacent to the international boundary during the past four years, but careful examination of the areas at collecting sites revealed no established infestations of this pest until in November of 1959 when three small outbreaks were discovered, two of which are in the southern portion of Chateauguay County and the other in eastern Huntingdon County. Plans are being made to conduct control measures in the spring of 1960. The European corn borer, Pyrausta nubilalis (Hbn.), was found in New York late in 1919 and in southern Ontario during the following year. Co-operative surveys were conducted in southwestern Ontario in subsequent years and an exchange of information in connection with spread, methods of control, etc., was in effect for many years. The Japanese beetle, Popillia japonica Newm., introduced to the eastern states some forty odd years ago, is a well known pest to millions of people, both rural and urban. As it spread toward central Canada where conditions were regarded as most favourable for its establishment, information concern- ing its habits, host plants, survey and control measures, was readily provided by federal and state officials. Since 1941 a number of infestations of this pest have been found in southern Ontario and, with provincial assistance, treat- ments have been applied. This action has not only been of benefit to Canada but to the United States as well, by retarding a sort of backdoor approach to non-infested or highly-infested areas of the middle west. The Dutch elm disease, caused by the fungus Ceratocystis ulmi, (Buism.) C. Moreau, carried by elm bark beetles, became established in the eastern United States several years before any evidence of the disease was observed in Canada. When surveys were organized in Canada we were able to benefit from the knowledge obtained through years of experience in the United States and trained personnel was made available to Canada to provide instructions on symptoms and methods of sampling. The Province of British Columbia is probably the only large peach-growing area in North America in which the oriental fruit moth, Grapholitha molesta (Busck), has not yet become established. In the fall of 1956 living larvae of this pest were found in peaches imported for canning purposes and, before positive identification was made, cannery refuse had been dumped Proc. ent. Soc. Ont. 90 (1959)—1960 38 a 2)” _ = and spread throughout an adjacent orchard. A specialist from the United States was engaged and it was recommended that the two canneries con- cerned be fumigated with methyl bromide, as well as the dump area and the 8-acre orchard, following destruction of the trees. Plant Protection Division personnel were unfamiliar with large scale fumigations of this nature and the Plant Pest Control Division of the U.S.D.A. very generously made available the services of one of their senior officials who had a great deal of experience in connection with Khapra beetle control. This action was very much appreciated and contributed in no small way to the successful completion of the project. The results of intensive trapping at fumigation sites and surrounding orchards during the past three years have been negative. Other surveys in which both countries have co-operated, or are co-operating, include the pear psylla program in British Columbia in the early 1940's, soil surveys for cyst-forming nematodes, and the ship inspection program carried on at Canadian seaports for a number of years. Films dealing with many insects and diseases have been prepared in the United States and these have been provided to the Plant Protection Division for staff conferences and for showing at meetings of various societies. The St. Lawrence Seaway opening in 1959 has enabled large ocean vessels to proceed almost to the center of the continent to discharge cargoes with the possibility of introducing pests which normally would be intercepted at salt-water ports. It is anticipated that conferences will be held during the coming winter between officials of both countries, including those of the central states particularly concerned, in an endeavour to work out a co-operative plan for the inspection of incoming ships and their cargoes and to devise a plan for the exchange of information relating to the conditions found. Following the discovery of the alfalfa weevil, Hypera postica (Gyll.), in Utah in 1912, surveys by state, federal and Canadian authorities were conducted until 1923 or 1924. There was little evidence of northward spread beyond the southern border of the State of Montana. In 1925, Cook, in a paper on the distribution of this species (Jl. Agric. Res. XXX No. 5) delimited the area of northern spread to the line running east and west near the state boundary of Wyoming and Montana. Surveys were subsequently discontinued. Whether or not continuing surveys and control would have prevented the spread and establishment of the species through Montana and into Alberta is of no particu- lar concern at the moment, but it merely points up the fact that no species is statis and that changes of even a minor nature in either the insect or the weather pattern can bring about extensive changes in the range occupied by a species. A similar situation obtained with respect to the European corn borer, Pyrausta nubilalis (Hbn.). As late as 1935, it was believed that this species had reached the limit of its western range at the Mississippi, but here again it has spread through Iowa, northward into Manitoba and Saskatchewan, and has been taken on at least two occasions in the east central part of Alberta. Just how far we should go to retard spread of these introduced pests is problematical. Once they have become firmly established and adapted, it is probably possible only to effect some delay in spread. By early detection, it is possible to eradicate a pest, as has been demonstrated on several occasions such as the Mediterranean fruit-fly outbreaks in Florida. As pests are no respectors of political boundaries, the surveys and any other methods of pest detection and interception are of mutual benefit to Canada and the United States. The cleser we can work together in this area with exchanges of information, materials and, at times, personnel, the more likely we are to achieve a degree of success. (Accepted for publication: March 15, 1960) Proc. ent. Soc. Ont. 90 (1959)—-1960 39 SHOULD EXTENSION WORKERS BE CLOSELY ASSOCIATED WITH RESEARCH? — THE RESEARCH AND TEACHING VIEWPOINT’ A. A. BEAULIEU’ To avoid possible ambiguity, I wish to note that I will apply this topic assigned to me by the Program Committee only to a Government organization carrying out entomological investigations. However, I consider that my remarks could be applied to a great extent at the levels of University and Industry, and in a general way, to most spheres of agricultural research and extension activities. I would like to point out, in passing, that I am much more familiar with the research than the teaching viewpoint. I propose to deal with this topic under the three following headings: the responsibility of a government in carrying out entomological research work; the responsibility of entomologist-research workers regarding extension activities; the close physical association of research and extension-entomologist workers. THE RESPONSIBILITY OF A GOVERNMENT IN ENTOMOLOGICGAL RESEARCH WORK I assume that all of you are familiar with the types of entomological research commonly carried out at government institutions. These have been reviewed and defined by Glen (2, 3), who stated that “background” and principally “development” research have continued and will continue to dominate govern- ment applied research programs, whereas “basic” research might represent only 5 to 10 per cent of the entomological research work carried out. The primary concern of a government department of agriculture in carrying out research work in entomology, whether it be in Canada or elsewhere, 1s obviously the welfare of the public at large, and more specifically, the protection of the agricultural industries, growers and trade organizations. It is of course, necessary that these people be kept informed of the developments achieved through the research. In development research work, according to Hiscocks (4), the value of the end-product to the community can be easily appraised. Moreover, as the tax- payer is the sole supplier of funds for government research program, he can legitimately expect that the government will provide him with information derived from research activities. It is reasonable to suppose that the tax-payer can expect such information in a form consistent with his level of scientific understanding. Under normal circumstances, information to be released to the public should be organized on a regular and continuous basis. However, this procedure should not impede special publicity campaigns or other extension activities which may become necessary in time of insect epidemics or other imminent threats. THE RESPONSIBILITY OF ENTOMOLOGIST-RESEARCH WORKERS REGARDING EXTENSION ACTIVITIES Entomological research work rapidly matures and becomes more and more highly specialized and divided into various disciplines such as ecology, physiology, genetics, toxicology, etc., concurring to what is still summed up by the one word 1Presented as part of a symposium on training for extension service at the joint meeting of the entomological societies of America, Canada and Ontario at Detroit, Michigan, November 30 - December 3, 2Research Laboratory, Research Branch, Canada Department of Agriculture, St. Jean, Quebec. Proc. ent. Soc. Ont. 90 (1959)—1960 40 entomology. Research workers are becoming more and more deeply concerned with keeping pace in their own respective fields of research and, as a result cannot spare, voluntarily or on request, the time necessary to popularize their findings. Moreover, as indicated by Hiscocks (4), many research workers are satisfied solely by producing excellent research work and scientific papers, and _ have neither the interest nor the ability to popularize them. The writing of scientific papers is most necessary in order to make findings available to other research workers and can be considered the most important single stimulus to the research worker. However, in a research program sponsored by a government, such activity does not inform the majority of the people originally designated to benefit from it. Extension, as defined by Hutchison (5), is “the science and art of effective communication with rural people’. I do not intend to dwell on the philosophy, psychology and principles associated with extension, as these factors have been well elaborated by Hutchison (5), and Neilson (7). Of the many extension outlets which release scientific and technical inform- ation, the ones that appear most useful, taken in random order, are: extension bulletins; pamphlets and like publications; articles for the press and the local newspapers; talks and interviews at radio and television stations; addresses at agricultural industry agencies and farmers’ group and association meetings; and last but not the least, advice to individuals on their particular problems. It should be evident that all these activities cannot be carried out by the research staff without serious inconveniences which would impose on _ the researcher strain and burden, curtailing his research work and seriously handi- capping the pursuit of his main work and functions. Research and extension are two distinct fields but each one requires its own thoughts, initiative and ability. Few men can qualify to fulfill both func- tions equally well. Yet extension must be fed by research and maintain a vital relationship with it. Obviously the research worker has the responsibility of supplying the basic facts and of explaining or verifying to some extent the interpretation of these facts. Beyond that it becomes the province of the extension worker (radio, T.V. ‘and newspaper reporters; extension writers; field men, etc.) to present them in a palatable form to the public concerned, without sacrificing the integrity of the original findings. Hutchison (5) concurs, when he points out that “imple- menting extension, or making extension work, involves the integration of three major levels or areas in the communication chain: 1— The research, experimenta- tion and fact-finding institutions; 2— The transmitters, interpreters and initiators in communicating agricultural information; 3— Those who make use of the information and assistance, such as extension audiences, farm families and many others”. Hutchison compares these three levels to the commercial channels of “wholesaler, middleman or retailer, and the buyer or consumer’. In development research, the research worker would benefit in many ways by spending a minimum of his time, from 5 to 10 per cent at the most, to extension activities directly related to his research projects. Such activities could be spread out according to circumstances, among the different extension outlets mentioned previously. That would permit him to judge for himself the practical value of his work and recommendations. He would be able to see whether improvement could still be made and also to detect new problems to be solved. Such extension activities can be considered necessary stimuli to the researcher engaged in development research. At this point, I wish to add that even those engaged in “basic” research would draw marked benefits from such casual contacts. Proc. ent. Soc. Ont. 90 (1959)—1960 4] THE CLOSE PHYSICAL ASSOCIATION OF RESEARCH AND EXTENSION ENTOMOLOGIST WORKERS Since entomologists engaged in development research work and extension workers share the same ultimate objective: to provide technical assistance to the same groups of people, it is most important and necessary that they maintain the closest association and relationship. There is much mutual benefit to be derived if they are located in the same vicinity. That would make possible the contacts necessary for the mutual understanding of their respective work and problems. At any rate, the channels. of communication between the research and extension workers should be efficient. If extension depends on research for up to date remedies, research expects from extension information on new problems to be investigated. Several factors interfere with the association of the research and extension in a government organization. The factors depend on the constitution which determines its spheres of activities, its obligations, and its territory. These vary largely from country to country so that there is no one general pattern I can think of to fit such a diversity of situations and interest. However, as a matter of interest, I will mention briefly the organization existing at present in a few different countries. For instance, in England and Wales, extension is organized on a nation-wide basis through “The National Agricultural Advisory Service’. This Service is under the general supervision of the Ministry of Agriculture and Fisheries. In London there is a small Headquarters staff giving policy direction to eight Provincial Centres and four Sub-Centres sharing the sixty-two counties of England and Wales. This assures a more uniform assistance to the different counties and branches of industry to be served. The relationship between these extension units and the research centers is greatly assisted by locating the various units side by side (1). In France, the Plant Protection Service of the Ministry of Agriculture in Paris operates a plant protection service on a basis somewhat similar to the N.A.A.S. in Egland. It coordinates the work of the twelve regions covering the whole country and the necessary relationship is maintained with the closest research centers established in different regions (6). In the United States, if I am well informed, the organization of extension varies somewhat with the individual State organization. Generally, it is a combined effort between the State University, the State Experimental Farm, the State government, and some time the Federal government. In Canada the “development” research is mainly the responsibility of the Federal government which operates research establishments or centers in each of the ten provinces, whereas responsibility for the extension is largely assumed by the provincial governments, although a good amount of practical information is also released in all provinces by the Federal government through its Informa- tion Division. Consequently the association between entomological research and extension organisms lacks uniformity and fluctuates considerably from province to province. Although it can be emphasized that research and extension workers should maintain congenial relations, these should not interfere unnecessarily with their respective primary duties. Their precious time must be protected. This can be achieved most adequately through one or more research-extension liaison officers located at each research institution doing development research. I shall not develop any further this topic assigned to the next speaker. LITE RALURE CIPD (1) ANonyMous, (1954). The National Agricultural Advisory Service. Anstey Hall, Trumpington, Cambridge. Proc. ent. Soc. Ont. 90 (1959)—1960 42 (2) GEN, R. (1958). Elements of entomology — The program. Bull. ent. Soc. PIMen. 42° 40-4.9, (3) ———— (1959). Education for agriculture: whose responsibility? Agric. Inst. Neve 43520-27394 (4) Hiscocks, E. S. (1956). Laboratory administration. MacMillan, Lond. (5) Hurcuison, L. F. (1959). Extension is effective communication. Agric. Inst. ew sgid.28:32,/99. (6) JouRNET, P. (1957). Personal communication, Paris, France. (7) Nettson, C. L. (1959). ‘Trends in extension entomology in Canada. Ann. Rep. ent. Soc. Ont. 88: 32-38. 1958. (Accepted for publication: March 4, 1960) RESEARCH - EXTENSION LIAISON’ G. F. Manson, L. A. Mitter, J. A. Becc ann H. B. WRESSELL To confine our remarks on this topic we propose to over-simplify the subject by defining research as the pursuit of new knowledge and extension as effective communication of knowledge. We are, therefore, considering the effective com- munication of new knowledge. Since we are primarily interested in entomology, we will limit the discussion largely to this field. To further clarify our approach we propose to discuss the subject from the viewpoint of a relatively small entomology laboratory under the Canada Department of Agriculture. The primary function of this laboratory is research, which varies from basic to applied. Because of the laboratory’s close proximity to field problems, the extension demands are considerable. The area of investi- gation covers approximately six counties but it serves in an advisory capacity for all of Ontario and often beyond. The work centres on problems of field, canning, and vegetable crops, but carries a service responsibility for the full field of entomology. The terms of reference of this laboratory are broad but indicate a primary responsibility for the development of new knowledge through research. The second duty is to make this new knowledge available in such a form that it will be used. A distinction is made here between new and general knowledge. For those unfamiliar with Canadian history, the British North America Act of 1867, constituting the Dominion of Canada, delegated education as a provin- cial responsibility. Extension is classed as education and, therefore, falls within the jurisdiction of the provinces. Agricultural Representative and other Exten- sion services, somewhat resembling the United States County Agent organization, have been set up in most provinces, basically for the purpose of extension. The lines of demarcation between the federal and provincial services are not as sharp as this statement might suggest, but the general areas of activity are thus indicated. 1Contribution No. 5, Entomology Laboratory, Research Branch, Canada Department of Agriculture, P.O. Box 488, Chatham, Ontario; presented as part of a symposium on training for extension service at the joint meeting of the entomological societies of America, Canada and Ontario at Detroit, Michigan, November 30 - December 3, 1959. Proc. ent. Soc. Ont. 90 (1959)—1960 43 ne) ve eee Let us make it quite clear that we did not accept this assignment because we felt we were authorities on either research or extension. We hope that by discussing this problem we might learn how best to share the responsibility of placing our research findings in the hands of the growers in a form in which they will be used. We think we are on safe ground when we state that it is the responsibility of the research staff to provide the new knowledge. Most of you will also agree that extension men, trained in the interpretation of information for growers, should be entrusted with the dissemination of this knowledge. This is certainly another case of over-simplification as it fails to consider ways and means and borderline cases. Perhaps by. examining the tools of the extension man’s trade, we can find ways of assuring the efficient flow of new knowledge to erowers. PUBLICATION We consider it the responsibility of every research man to place the significant results of his work in the literature of his discipline. Often this record is highly specialized and may be of little use to the extension man who cannot hope to be a specialist in all aspects of agriculture. There would seem to be at least two or three ways of overcoming this problem. As long as the research worker has not lost his touch with the field application, he might rewrite his findings in terms the extension man can interpret. He might go a step further, if he has some extension ability, and attend a few grower meetings with the extension man and discuss his findings. In this way, the information soon ceases to be new and becomes the responsibility of the extension worker. The joint preparation of control programs is an excellent time for research and extension workers to bring their thinking together. There is no room in these publications for misinterpretations, and in them a considerable part of the research program must be stated in terms the layman can understand. This process can be simplified if the extension man makes it his responsibility to discuss the research in progress periodically with those who are conducting it. A second method might be to have extension specialists in the major fields of study in the area, preferably attached to the research centre of their specialty. These men would keep abreast of the research and would be in a position to carry the results direct to the grower and be the link between research and general extension. A possible third method would be to have the information services rewrite the technical papers in suitable terms for extension. We consider this the least desirable as much may be lost in the interpretation process. “MASS MEDIA” A most enlightening editorial in Nature (Aug. 29, 1959) reviews the results of surveys in the United States and Britain on the impact of press, television, and radio on the dissemination of information on science. The press still main- tains its place at the top of the media in this field. Though the potential of television is admittedly still underdeveloped, it is already second in importance in the spread of scientific news. In the United States, and probably in Canada, all but one per cent of the private dwelling units are covered by one of the mass media. Seventy-six per cent of those interviewed recalled at least one scientific item they had read or seen recently. It is clear from the analyses of the data obtained that the degree of formal scientific education of the public is an important factor in their later absorption of science information from the press, T.V., and radio. While we may share the editor’s concern for the over-all levelling influence of the mass information process, we can hardly afford to Proc. ent. Soc. Ont. 90 (1959)—-1960 44 disregard it as a valuable means of extension. ‘The question arises as to how and whose responsibility it is to improve both the quality and quantity of the scientific information on entomology reaching first, the growers, and secondly, the general public, through mass media. Two or three points seem fairly obvious to us in this situation. In order that we may have an intelligent public receptive to future scientific information, we should all make it our responsibility to see that the scientific education in our schools is sound and adequate for life in a world in which science plays so large a part. We should be prepared to assist in any way we can with that phase of education. We should not stop with the schools but should make it part of our job to inform the public on our work whenever possible. By their nature, research men are not usually proficient at publicizing their own work. This is much better left to extension personnel, and more especially those with a flair for popular scientific writing. In the area of extension, through mass media, we should make special mention of the value of regular farm broadcasts on both radio and T.V. The whole agricultural press also plays a very important part in shaping the thinking of our growers. Close liaison between these sources of information and our research and extension men will benefit all concerned. A discussion of mass media brings to light a phase of extension which we have omitted so far. Our thinking should rightly centre around the informing of the grower but in our governmental organizations the general public con- tributes, through taxes, to agricultural research and extension. A public better informed on what is being done and how they benefit will be much more cooperative than they would under “taxation without information”. MEETINGS Meetings have always been an important means of communicating infor- mation. These are most effective when growers with specific interests come together. The level of knowledge of their problems among a group of specialized growers demands a high level of information. This means that they are often close on the heels of the research man. As we noted earlier, if the research man has extension ability he may be well suited to give his new information to the erowers and extension staff at the same time. On the other hand, the fact that the growers are so close behind him makes it imperative that he should be concentrating on his research so the source of information will not dry up at a critical point. INDUSTRIAL RESEARCH AND EXTENSION Surveys of sources of information -for growers have shown that dealers stand near the top of the list. These surveys do not show the dealers’ sources of information. We know that a lot of it comes from extension services and research men in the form of control calendars and direct contacts, but no one should underrate the importance of the technical and sales staff of industry as a source. We know that many of the technical representatives of industry were recently recruited from the ranks of Government or University research — therefore, we do not dare question their qualifications!! We also know that by and large these men, while interested primarily in their company’s product, are honestly interested in the welfare of the grower and render him and us a valuable service. I think even they will admit, however, that their company’s extension program is usually indistinguishable from sales promotion. Another important link in this matter of communication of new knowledge is the field staff of companies growing and processing specialized crops. While these men are primarily interested in their own products, they must be inter- Proc, ent. Soc, Ont. 90 (1959)—1960 45 ésted in the grower’s whole program. These men draw much of their information from their company research, as well as governmental research and extension services. Often as a result of their efforts, new information is quickly put into practice. With the advent of better custom operators, they are also passing on new information from all sources to the growers. They are likely to continue to increase in importance, as customers for our information, as the control programs increase in complexity. INDIVIDUAL CONTACTS Extension by individual contacts, like other individual teaching, is recog- nized as superior to teaching by large groups, but it is seldom economically possible. Perhaps this is a hasty evaluation when we consider that the two-way flow of information is at its best when grower and extension or research man meet face to face on a problem. Many growers who are too reticent to express their views, or even ask questions at a meeting, will discuss their problems freely in the field. In almost any agricultural research program, the professional workers need to be confronted periodically with the grower’s problems in order to keep the direction of their research straight. Individual contact with key growers may be essential in initiating the application of new research. The spread by imitation from such key growers is often a good measure of the practicability of the research recommendation. Such cooperative work may often be looked upon as the final or demonstration stage of the research process. Whether this should be done by extension or research staff depends largely on how closely they have worked together in the initial stages and on the personnel involved. We have already mentioned the value of individual contacts between research or extension men and dealers in agricultural supplies or custom operators. Through the personal contact of these men, the results of research often reach the growers with surprising speed. RECAPITULATION Under the restricted definition and conditions of extension and research we have examined some of the more obvious aspects of the problem of efficiently putting the results of research in operation. We have kept an open mind on who should do what, except for the broadest delegation of responsibility for development of new knowledge and the communication of that knowledge. We have examined some of the means whereby the information may be spread but have not offered much by way of new approach to the question of transfer of research to the extension man which, in essence, is the problem assigned to us. Probably the greatest virtue of our presentation lies in its brevity and that thus we have conserved some time for discussion which we hope will follow imme- diately. May I express the hope that in this discussion you will be pointed and brief in order that we may obtain as broad a spectrum of opinion on this problem as possible. LITERATURE, CIRED (1) Anon. (1959). Mass media of communication and scientific developments. Nature 184: 659-662. (2) Baxer, H. R. (1959). Agricultural extension in Canada; the emerging role of the extension worker. Symposium on Extension, Can. Agr. Chem. Assoc., Quebec City. Univ. Sask., Saskatoon. Proc. ent. Soc. Ont. 90 (1959)—1960 46 (3) Bett, C. E. Jr. (1959). The forward look in extension. Agric. Inst. Rev. Ne cg PAST 3 | (4) Cram, J. S. (1956). What should we do with extension? Agric. Inst. Rev. 11: 11-14, 68-73. fo) GEEN, RR. (1959). Education for agriculture: whose responsibility? Sym- posium on Education for Agriculture, Agr. Inst. of Can. Ann. ere Winnipeg, Man. Res. Branch, Can. Dept. Agr., Ottawa. (6) GopgoutT, J. A. (1955). Service to agriculture. Agric. Inst. Rev. 10: 38-40. (7) GouLpEN, C. H. (1959). Extension policy of the Department of Agricul- ture. Symposium on Extension, Can. Agr. Chem. Assoc., Quebec City. Res. Branch, Can. Dept. Agr., Ottawa. (8) GouLpEen, C. H. (1959). Public relations. Res. Branch, Can. Dept. Agr., Ottawa, Circular 1959-55. (9) Hare, H. R. (1951). A new approach to agricultural extension. Agric. imst, Kev. 6:° 11-13; 56. (10) Hurcuison, L. J. (1959). Extension is effective communication. Agric. Inst. Rew. 17: 28-32, 59 (11) Jounson, T. A. (1954). Weak spots in Canada’s agricultural extension system: Acric. jinst..Rev.9: 24,. 26. (12) Lanrz, K. E. (1959). Agricultural extension. Symposium on Extension, Can. Agric. Chem. Assoc., Quebec City. Ont. Dept. Agr., Toronto. (13) Neirson, C. L. (1953). Government-sponsored advisory services. Agric. Inst. ev.73° 7 7/,. 78. (14) Nermson, C. L. (1958). Trends in extension entomology in Canada. Ann. Rep: ent. Soc. Ont. 89: 32-38. (Accepted for publication: March 4, 1960) WHAT TRAINING SHOULD PROSPECTIVE Sion WORKERS RECEIVE AT COLLEGE?’ F. O. Morrison Knowledge, especially when it can be applied to the welfare of man, is a saleable product and like any other saleable product must be marketed. Where the more tangible products of human effort are concerned, high development in the technique of marketing characterizes the success of our western civilization. It is a far cry from the day of the country store and the green grocer to the modern American supermarket. Now the modern research laboratory doesn’t have to yield second place to any production line today. A quick look at the 1Contribution from Macdonald College of McGill University; presented as part of a symposium on training for extension service at the joint meeting of the entomological societies of America, Canada and Ontario at Detroit, Michigan, November 30 - December 3, 1959. Proc. ent. Soc. Ont. 90 (1959)—1960 47 programme of these meetings will readily convince anyone of the depth and = extent of the investigations being conducted in the basic field of insect physiology, ecology, toxicology, etc. Nor are the possible applications of these discoveries being overlooked, but what is being done about acquainting the farmer or the housewife with the practical knowledge so gained and probably more important still inducing them to utilize it. Extension like teaching is a problem of communication. Present contro- versies on education and the international situation at the moment, both suggest that we could do with considerable research in the field of effective communica- tion itself. Extension workers have an even more difficult problem than the teacher for they do not have a captive audience and must not only impart information but motivate or stimulate the listeners to make use of what they have to offer. Moreover, the audience varies in educational levels, attitude, goals, aspirations, age, needs, interests and enterprise. In this connection I should like to quote from an article by L. J. Hutchinson, entitled “Extension Is Effective Communication” and which appeared in the Agricultural Institute Review, for July and August 1959. Mr. Hutchinson says “Effective communica- tion requires considerable knowledge, dexterity and adaptability on the part of the extension worker to recognize these variables and meet the situation by creating the best environment for natural communication while at the same time utilizing methods and technique that are suited to meet the requirements of the situation and the audience.” There is grave doubt as to whether we are using our full know how in this job, and certainly only very recently spurred on by a commercial motivation studies have we begun even in a feeble way to assess the results of our endeavours. So far as I know no study of the effectiveness of entomological extension as such has ever been made. We just don’t know which methods are best or whether our workers are wasting their time or not. We are using horse and buggy methods of entomological extension in an atomic age. We need extension supermarkets and trained managers for them. These managers will be the middlemen between the investigators and the farmer. They need an appreciation of the points of view of both. We have been content in many instances I fear, to leave this work to purely commercial salesman or at the government level to students without the academic capacity for research work. In turn we have offered for this service, substantially lower financial reward than for research. As a result the research worker all too often looks down with a cetain intellectual snobbishness on that lesser breed the extension worker. This attitude is based on the outmoded conception of the extension man as a mere technician. But to sell our products, our extension worker must be more than a trouble shooter to call in in time of difficulty. He must be able to instigate control programmes at the policy level. To do this the extension man must integrate his work with the community, provincial, state and federal workers and policies. Examples of success in such integrated pro- erammes with multiple support exist in the excellent work of W.H.O. against msects of public health importance and in locust control work in Europe. The key to success in such larger efforts is a back log of confidence founded on practical solutions which have been supplied. It is the man who has a record of successfully eliminating ants from kitchens and wasps from garages, who commands respect when he talks of community-wide programme for warble fly reduction. To attract and train men for the type of extension we need, we require some changes in thinking and policy in our Canadian universities at least, and I suspect this is also true in many American institutions. By and large we are geared to train research workers. The instructional staffs are trained and Proc. ent. Soc. Ont, 90 (1959)—1960 48 engaged in research. A researcher engrossed in his studies tends to shy away from any taint of commercialism, even though he may complain that his discoy- eries are not appreciated or duly rewarded. In this atmosphere a student without a research bent is apt to feel somewhat out of place. Many of those who have made a success of extension were trained as research men and became of necessity largely self-trained extension workers. This method lke the time honored one of tossing the youngster into the water to teach him to swim, meets with some success but is not calculated to produce whole classes of good swimmers without undue casualties. Forced by the title of this paper to think about the task of training operators for our entomological supermarkets of the future, or if you prefer a different simile, entomological practitioners with a successful farm-side manner, I became more and more astounded at the magnitude of the task. What is to be expected of our extension man? If we continue to consider him the operator of informational supermarket, it is clear that he must be both entomologist and husbandryman. He must know the art of communication by the written and the spoken word and through such media as radio and television. He must pack his goods in usable amounts. He must keep on hand a wide variety of materials. Just as the supermarket has found it wise to carry magazines, aspirins and dish mops, our operators must be prepared to dispense at least basic information on husbandries, fertilizers, food preservation, sanitation and house- hold management. There must be no uncertainty about what he provides, for every time the local hardwareman’s remedy works better than his, not only he, but the researcher as well loses face. As the supermarket offers convenience, space and even delivery service, our operator must be prepared to serve at the growers convenience and even to demonstrate right on his property. He must be well versed in economic farm production. In brief our extension superman or supermarketman should be entomologist, plant pathologist, husbandryman in several fields, teacher, (that is communications expert par excellence,) economist and socialist, filled with the love of mankind and missionary zeal. He must be a dedicated man indeed. Now what shall we offer our young hopeful at college to fit him for a career in extension entomology? Without question much of his training must be of an in service nature, and this may well begin during summer vacations. Such a scheme requires good co-operation between government agencies, com- mercial concerns and the universities. This offers no problem as such co-operation is pretty general now, though some cutting of red tape may be necessary. What the summer experience will be should to some extent be under the control of the professor or advisor at least as to its scope. What the student should be offered in the way of university courses is the question we are faced with now. Allowing a college year of seven months, with two terms of equal length, as is generally the case in Canada, I would suggest a minimum of five years of university instruction. He might in that time be granted a bachelor’s degree in entomology and a first diploma in extension. Allowing three hours of instruction per week for one term as a unit, and ten such units as a full student load for one term, (that leaves very little spare time) our aspirant can in five vee be subjected to one hundred units of instruction. As a target to shoot at, I suggest forty units of basic sciences, eighteen units of humanities, twenty-six units of entomology. SBWGGESTED LIST OF UNIVERSITY SUBJECTS TO BE TAKEN BY A STUDENT INTENDING TO WORK IN ENTOMOLOGICAL EXTENSION EAS Ge SI GTC EIN | G1 ONG Gi ao era a eer efi naar Gr oie yee ae OE eer ee nee ere 40 units Chemistry (inorganic, organic and biochemistry) ..............0..0.0.0 cee 12 Proc. ent. Soc. Ont. 90 (1959)—1960 49 Botany (including mycology, plant pathology and bacteriology)............ 10 6 Mathematics (including statistics): 2.5000) ie. eee Physics (Gncludine mechanics of sprayer, ete).3..0 04:2 8 Zoolegy (inctuding general: physiology) 2225) 4) 2.2.2 6 TVA IS Siete acute ee ee es mate CEE Oe cue ae Paes. 18 units Enelish (composition (and, public, speaking) 22)... ee 8 ECOMOMICS 226. a ee ee ee 4 Sociology and Psychology ..0.... 2 eee 6 ENFEOMOL OGY oo 8 i aes ee ee ae ee nC Jn ee 26 units SYStEMALICS ii is Se Gree gee ech 8 Applied biology :.0.80.. cokes RRe ae gee ek 8 TECOLOBY goes ee Se oe Oo 6 Morphology = 2.00.80 cae oe ee ee, a ee 4 EPOSBANDIR LES oe oe oe ei oe ee 6 units Chosen from Horticulture, Agronomy, Animal Husbandry, or Poultry Husbandry. This seems to me the bare minimum necessary to start with. It leaves no time for extension techniques, the skills of conducting public meetings, writing extension bulletins, preparing exhibits and television demonstrations. These ‘must be learned in his spare time or during in service training. The time ‘allotment for the husbandries is hardly adequate. However, after a period of field work, one or two years of additional study and a thesis could lead to a graduate degree jointly in entomology and extension. Only when we establish this sort of programme and when commercial and government agencies offer the same finnancial support for candidates pursuing advanced work in the art of extension as they do for others doing research, and only when the financial reward for those who have taken the extra training is adequate, can extension in entomology take its rightful place. (Accepted for publication: February 18, 1960) 50 NTIFIC NOTES THE NEMATODE HOWARDULA BENIGNA COBB, 1921, PARASITE OF THE CUCUMBER BEETLES IN ONTARIO L. J. BriANn’ The entomophagous nematode Howardula benigna Cobb, 1921, is parasitic on cucumber beetles: Acalymma (= Diabrotica) vittata (Fab.) and A. (= Diabrotica) trivitta (Mann.) its main hosts, and Diabrotica undecimpunctata howardi (Barber) referred to as 12-punctata by Cobb) a host of secondary importance. Cobb. (1, 2) states that the geographical distribution of this nematode is approximately the same as that of its main hosts in the United States. His distribution map showed one point in Canada at Vineland, Ont., where it was known to occur. Small scale surveys in Prince Edward, Hastings, and Northumberland Counties, Ontario, in the summers of 1958 and 1959, showed the presence of H. benigna in the striped cucumber beetle, A. vittata, with parasitism averaging 7.6 and 2.5 per cent in the two years. It was not observed in D. undecimpunctata howardi, which is also common in this region. A. trivittata does not occur in Eastern Canada. PEE RAT URE ChE ED (1) Cops, N. A. (1921). Howardula benigna; a nema parasite of the cucumber beetle Science. n.s. (1409) 54: 667-670, Figs. 1-4. (2) Coss, N. A. (1921). Howardula benigna; a nema parasite of the cucumber beetle, (Dia- brotica). Contr. Sci. Nematol. (Cobb), (10), 4 pp., Figs. 1-4. (Accepted for publication: February 1, 1960) i—~ntomology Research Institute for Biological Control, Research Branch, Canada Department of Agriculture, Belleville, Ontario. MICROSPORIDIA IN A SPERCHONID MITE, AND FURTHER NOTES ON HYDRACARINA AND SIMULIIDS (DIPTERA)' D. M. DAVIES Five ovipositing female water mites, Sperchon nr. jasperensis Marshall’, were collected on May 27, 1959 in Costello creek at its exit from Costello lake, Algonquin Park. One of the mites was infected with Nosema sp*. This is apparently the second record of a microsporidian in Acarina, the first being found in a tyroglyphid mite from Bohemia (2). Many red sperchonid egg masess were on the rocks between numerous larvae and pupae of Simultum venustum Say and some of S. vittatum Zett. Adult female mites laid eggs on moist filter paper. Eggs began hatching after 12 days at an average temperature of 68°F. (4 days at 55°F. and 8 days at 75°F.) and hatching continued for 3 days. This is similar to previous observations when incubation was 11-17 days at 66°F. (1). When a pupa of S. venustum was placed in the petri dish on the moist filter paper on which the mites were hatching and crawling, almost all the larval mites gathered within the cocoon although they did not appear to feed on the pupa. They may congregate in the cocoon and transfer to the adult fly while it emerges, as was suggested previously (1). Sperchonid larvae were associated with recently emerged adult black flies at Churchill, Manitoba in 1948, but no adult hydracarina were collected (1). Recently Mr. R. W. Dunbar sent me 14 adult mites taken on June 16, 1955 from a stream 4 mi. east of Warkworth lake at Churchill. These were identified as Sperchon nr. jasperensis*, but were different from the adults of Sperchon from Algonquin Park. Further taxonomic study is required before the specific identity of these sperchonid mites is established. LITERATURE CITED (1) Davies, D. M. (1959). The parasitism of black flies (Diptera, Simuliidae) by larval water mites mainly of the genus Sperchon. Canad. J. Zool. 37: 353-369. (2) WeEIsER, J. (1956). Nosema steinhausi n. sp., a new microsporidian infecting the mite, Tyrophagus noxius (Acarina, Tyroglyphidae). (in Czech). Csl. Parasit. 3: 187-192. (Accepted for publication: March 16, 1960) 1Contribution from Department of Biology, McMaster University, Hamilton, Ontario, with the support of a grant from the National Research Council. 2Dr. R. D. Mitchell, University of California kindly identified the hydracarina. 8Drs. E. A. Steinhaus, University of California and J. J. Lipa, Instytut Ochrony Roslin, Poznan, Poland, kindly identified the microsporidian. Proc. ent. Soc. Ont. 90 (1959)—1960 53 CONTROL OF THE CABBAGE APHID, BREVICORYNE BRASSICAE (L.), WITH VARIOUS INSECTICIDES AT STOUFFVILLE, ONTARIO, IN 1958 - LL. M. Cass? In the late summer of 1958, the cabbage aphid, Brevicoryne brassicae (L.), was unusually abundant on crucifers in York County, Ontario. In the extensive cole-crop area near Stouffville, where observations indicated more than 10 million of the imsect per acre, growers had had only moderate success with malathion and Phosdrin, the insecticides generally used against the aphid in this area. An experiment was conducted in September in a field of late cauliflower near Stouffville to determine the reductions in numbers from single applications of various aphicides. Six materials, Schradan, NC 262, Guthion, and the aphicides recommended against this insect in Ontario (3), namely Systox, Phosdrin, and malathion, were tested at the concentrations listed in Table I. They were applied on September 4, the dusts with rotary hand dusters at 30-35 pounds per acre of the diluted dust, and the emulsible concentrates with knapsack sprayers at 80-100 gallons of the diluted spray. The experimental plots, one-sixtieth of an acre in size, were arranged in four randomized blocks. On September 18, by the method of Church and Strickland (1), the aphids were counted on 10 plants taken at random from each plot to determine the effectiveness of the insecticides. Differences between treatments were assessed by the multiple range test of Tukey as given in Federer (2). Table fi Reductions in numbers of the cabbage aphid on late cauliflower two weeks after application of various insecticides, Stouffville, Ont., 1958. Toxicant Number of aphids Percentage Material Formulation per acre, OZ. per 40 plants reduction Systox@ em. conc. 8 24 99.6 Schradanb em. conc. 16 192 96.8 NC 262¢ em. conc. 8 456 92.4 Phosdrind 1% dust 4 1,488 75.3 Malathione 4% dust 20 1,716 71.5 Phosdrin4d 1% dust 6 1,740 TVA Guthiontf 21%4% dust 16 3,516 41.6 Untreated — _ 6,024 — Difference required for significance at 5% level: 632 at 1% level: 773 aQ,O-diethyl O-2-(ethylthio) ethyl phosphorodithioate; Chemagro Corp., New York, N.Y. bbis (dimethylamino) phosphoncus anhydride; Fisons Pest Control Ltd., Cambridge, England. cO,O-dimethyl S- (N-methylcarbamoylmethyl) phosphorodithioate; Fisons Pest Control Ltd., Cambridge, England. dalpha isomer 2-carbomethoxy-l-methylvinyl dimethyl phosphate; Shell Oil Company of Canada Limited, Toronto, Ont. eO,O-dimethyl phosphorodithioate, S-ester with diethyl mercaptosuccinate; Cyanamid of Canada Ltd., Toronto, Ont. £0,O0-dimethyl S- (4-oxo-3H-1,2.3-benzotriazine-3-methyl) phosphorodithioate; Green Cross Products Division, Sherwin-Williams Co. of Canada Ltd., Montreal, Que. RESOL TS: Systox, Schradan, and NC 262 gave excellent reductions in numbers (Table I). Phosdrin ~ at both rates, and malathion, gave appreciable reductions but one application was not sufficient in the severe infestation of this experiment. Guthion was unsatisfactory, reducing the aphid population by less than a half. LITERATURE CITED (1) CHurcu, B. M. and A. H. StrickLanp. (1954). Sampling cabbage aphid populations on brussels sprouts. Plant Path., 3: 76-80. (2) FEDERER, W. T. (1955). Experimental design. Theory and application. MacMillan, Toronto. (3) Ontario Department of Agriculture and Canada Department of Agriculture. Protection calendar for vegetables (1958). Ontario Dept. Agric., Extension Branch, Toronto, Ont. (Accepted for publication: February 22, 1960) i—~ntomology Research Institute, Research Branch, Canada Department of Agriculture, Ottawa, Ontario. Proc. ent. Soc. Ont. 90 (1959)—1960 54 AN IMPROVED WAY TO DRY MOUNT MINUTE INSECTS C. V. WADE? The accepted way to mount small dried insects for collections is to glue each one to the point of a V-shaped piece of thin cardboard transfixed to a pin (Fig. 1A). This is simply Fig. 1. A. Usual way of mounting small dried insects; B. minute insect obscured by glue on ordinary mount; C. modified point for minute insects; D. minute insect mounted on modified point. called ‘pointing’, and it is described in most handbooks on entomological methods such as the recent one by Beirne’. Although it is quite suitable for insects over about two millimeters long, mounts of smaller insects are often unsatisfactory. Perhaps the most common trouble with mounting minute insects this way is that the ordinary cardboard point takes up too much glue, which in turn engulfs the specimen and obscures that which may be needed for study and ‘identification (Fig. 1B). I have found that this can be avoided by using a much finer point, preferably one that does not soak up the glue. A simple way to achieve this is to glue a piece of nylon bristle to the tip of an ordinary cardboard point. To do this, first select a suitable bristle from any nylon paint or bench brush (the smaller the specimen, the finer the bristle should be); cut a piece about eight millimeters long off the bristle and glue it to the underside of an ordinary point so that about three millimeters extends beyond the tip as shown in Fig. 1C. . To mount a minute insect to this modified point, place the specimen in view under a magnification of 10 to 20 times and position it on its left side. Then take up a droplet of glue on the tip of the bristle and press the tip firmly to the right side of the mesothorax; the specimen will hold to the tip after a few seconds, and if necessary its position can be finally adjusted before the glue sets (Fig. 1D). A suitable glue is of great importance, and I have found none better than the ‘shellac gel’ recommended by Beirne’. When a number of different kinds of minute insects have to be mounted at one sitting, it facilitates the work to first make up a number of the modified points with bristles of various sizes. I have used the above method to mount many species of minute insects, most of which were of the orders Coleoptera, Hemiptera, Homoptera, and Hymenoptera. LITERATURE CITED (1) Berrne, Bryan P. (1955). Collecting, preparing, and preserving insects. Canada Dept. Agric. Pub. 932. (Accepted for publication: March 3, 1960) 1Contribution No. 10, Research Station, Research Branch, Canada Department of Agriculture, Fredericton, New Brunswick. 2Entomology and Plant Pathology Section. Proc. ent. Soc. Ont. 90 (1959)—1960 55 oe Ae SUMMARY OF IMPORTANT INSECT INFESTATIONS, OCCURRENCES AND DAMAGE IN AGRICULTURAL AREAS OF CANADA IN 1959* C. GRAHAM MACNAY This summary of insect conditions in Canada in 1959 was prepared from regional reports submitted by officers of the Entomology Research Institute, provincial entomologists, and university professors. In general, common names used are from the 1955 revision of the list approved by the Entomological Society of America. To avoid unnecessary duplication, forest insect conditions are not included, this being adequately dealt with in the Annual Report of the Forest Insect and Disease Survey, published by the Forest Biology Division, Canada Department of Agriculture. GENERAL-FEEDING AND MISCELLANEOUS INSECTS BEET WEBWORM.—No damage by this insect was reported in British Columbia. In Alberta it occurred in much smaller numbers than in 1958, approximately 7,000 acres of beets having been sprayed as compared with 35,000 acres in 1958. In the vicinity of Saskatoon, Sask., it was a nuisance, but in the Province generally it was not of economic status. In Manitoba large flights of adults occurred in June, but larvae did not develop in expected numbers and infestation was less than in previous years. The insect was well controlled on beets and caused little damage to flax and forage crops. BLISTER BEETLES.—In British Columbia several spotty infestations of Epicauta oregona Horn occurred in the Kamloops area, causing minor damage to alfalfa, tomato, and potato. In Saskatchewan the Nuttall blister beetle damaged broad beans at Hawarden, Cumino sweet clover at Springwater, and caragana hedges in Saskatoon. In eastern Quebec small numbers of the black blister beetle developed in potato fields. CRICKETS.—In the Prairie Provinces the Mormon cricket occurred only in very small numbers. In Manitoba the field cricket was less numerous than in 1958, causing little damage, but in Kent and Essex counties in Ontario it was numerous and caused extensive damage to tomato fruits CUTWORMS.—In southwestern British Columbia no serious cutworm damage was reported, although outbreak conditions existed in 1958. The beet armyworm, recorded for the first time in Canada in 1958 when it infested vegetables near Ladner and Pavilion and was taken in light traps at Kamloops, was not found in 1959. In the dry, southern interior of British Columbia, cutworm infestations and damage were generally lighter than in 1958. In home gardens damage was spotty and light to moderate. No serious damage occurred in the Okanagan Valley or the Kamloops district. A few seedlings of alfalfa were heavily infested by the dark-sided cutworm in the latter area, but no economic damage occurred. A survey of the North Thompson River Valley for 100 miles north of Kamloops, not previously surveyed, revealed the red-backed cutworm and the dark-sided cutworm to be the most common and injurious species. Damage in gardens ranged from light to severe and some new seedlings of alfalfa were severaly damaged. In the Peace River area the red-backed cutworm severely dam- aged some cereal crops, flax, alsike clover, and garden crops. Greater damage was prevented by a disease that greatly reduced populations. In the Prince George area the variegated cutworm damaged cabbage in a market garden. In Alberta a few cutworm infestations were reported in Edmonton and vicinity. In all the parkland areas and in the Peace River area, severe infestations of the red-backed cutworm developed, but losses were smaller than in 1958. In southern Alberta, scattered light infestations occurred near the foothills. The pale western cutworm caused some damage in east-central agricultural areas of the Province and was readily found in southern areas, but crop losses were light. The army cutworm was not a pest. In Saskatchewan the pale western cutworm was more widely distributed and abundant than for many years, especially in west-central agricultural districts and east of Regina. Light scattered infestations occurred in several areas east of Saskatoon and in western Saskatchewan. A few crops were reseeded. The red-backed cutworm was abundant in th parkland area, being most numerous in the Melfort, Tisdale, Nipawin, and Hudson Bay districts of north-eastern Saskatchewan. Other infestations were scattered from Lloydminster on the west to Yorkton and Moosomin on the east. Although thousands of acres were sprayed, the crops in many fields were destroyed. Many gardens in Saskatoon were infested. ‘There were no reports of damage by other species. In Manitoba, cutworm infestations were general on sugar beets, flax, grain, vegetables, and ornamentals. Populations were larger and persisted over a longer period than usual. Damage in field crops was spotty, but in gardens it was general. The red-backed cutworm, the principal Species, was more injurious than usual. iContribution Scientific Information Section, Research Branch, Department of Agriculture, Ottawa, Canada. Proc. ent. Soc. Ont. 90 (1959)—1960 59 In southwestern Ontario the black cutworm was the principal pest species. Hundreds of acres of sugar beets and many fields of corn in Kent County were severely damaged. Pre- planting control measures protected tobacco transplants, but the black cutworm, together with the variegated cutworm, caused considerable mid-season injury to flue-cured tobacco in Norfolk County, and to burley tobacco in Essex County. In the Holland Marsh area various cutworm species extensively damaged vegetable crops. In eastern Ontario, cutworms caused more damage than usual to vegetables, and the armyworm occurred only in very light infestations in the Ottawa area. In Quebec, various species of cutworms caused about the usual amount of damage to vegetable crops, being particularly injurious to tomato and cabbage transplants. The fall armyworm occurred in some numbers on corn in the Ste. Martine and St. Jean areas. There were no armyworm outbreaks. In New Brunswick, cutworms severaly damaged garden crops in the Fredericton area and some extensive damage occurred in field crops in King’s County. The fall armyworm was generally present on corn, but damage was slight. The armyworm was present in the southern part of the Province, up the St. John River Valley to Nashwaaksis, and up the Nashwaak River Valley to Durham. In Nova Scotia the bronzed cutworm was less numerous in grassland at Cow Bay than during the previous two years and was reported from North East Margaree. The dark-sided cutworm injured spruce seedlings at Lawrencetown. There were no outbreaks of the armyworm. In Prince Edward Island the variegated cutworm caused some localized damage to straw- berry transplants. In Newfoundland, large populations of the black cutworm extensively damaged rutabagas and vegetables. EUROPEAN EARWIG.—This insect was occasionally reported in the lower Fraser Valley, and was more numerous than usual in central and southern areas of the Okanagan Valley and in the Armstrong and Salmon Arm districts. A EUROPEAN TORTRICID.—In Prince Edward Island, Cnephasia virgaureana Treit. was present in smaller numbers than in 1958. It destroyed the heads of common daisy and timothy and, although present in strawberry plantings, was not found in the fruit. GRASSHOPPERS.—In the interior of British Columbia, grasshopper populations were generally reduced. About 4,000 acres were sprayed in the Nicola control zone, 400 acres in the Clinton zone, and a few acres in the Pavilion Mountain and Kersley areas. A diapause year was believed to be the reason for reduced numbers in northerly areas, and extreme drought in southerly areas. Melanoplus bilituratus (Walk.), Camnula pellucida (Scudd.), and Asemoplus montanus (Bruner) were the principal species in the Nicola zone. C. pellucida was the only important species on Pavilion Mountain and in the Chilcotin area, but Melanoplus infantilis Scudd. was quite noticeable. Small pockets of M. bilituratus and M. bruneri Scudd. occurred from Williams Lake to Quesnel. Melanoplus femur-rubrum (DeG.), intermingled with several other species, occurred in normal numbers in the Okanagan Valley. In Alberta severe infestations were scattered throughout the extreme southern part of the Province, but in most areas damage was prevented by prompt control masures. An increase in numbers, particularly of C. pellucida and M. bilituratus, in 1960 was expected. Areas of severe infestation were expected to increase in the south and lesser degrees of infestation to extend northward. In Saskatchwan, grasshopper damage was relatively inconspicuous except in areas where control measures were omitted or were applied too late. In southeastern agricultural areas, outbreak conditions had been expected, but failed to develop except in a limited area in the extreme southeast. This was believed to be a result of a combination of wind erosion, cool weather, and spring drought. The amount of insecticide used in this general area was only slightly more than that used in 1958, 60,000 gal. as compared with 55,300 gal. Infestations in pastures continued to present a control problem on the basis of economy and poison residues. Fall surveys of adults indicated smaller populations than in 1958, but little change in distri- bution. No areas of very severe infestation were found, but heavy concentrations of C. pellucida were widespread in south-central and western agricultural areas, most of the latter being confined to the area adjacent to the south bank of the South Saskatchewan River from Swift Current to Leader and Fox Valley. The fall egg survey, incomplete because of unfavourable weather, indicated that all species had matured and oviposited normally. C. pellucida was the most important species in 1959, M. bilituratus failing to attain the status of a major pest. A few heavy infestations of M. bivittatus persisted in a few localities, but it, as well as M. packardii Scudd., was less numerous than in 1958. Three species normally non-economic were common in some localities: Aeropedellus clavatus (Thos.) was numerous in the Tessier district and was the major species in a community pasture at Lake Alma. Aerochoreutes carlinianus carlinianus Thos. was unusually abundant, as it had been for several years, and Encoptolophus sordidus (Burm.) was becoming increasingly conspicuous. The area of infestation forecast for 1960 was much the same as that forecast for 1959, both in extent and location. However, the areas included in moderate and severe categories were much reduced and no very severe infestations were anticipated. Although a reduction in general abundance was expected, it was considered that there would still be some areas of major infestation. Proc. ent. Soc. Ont. 90 (1959)—1960 60 In Manitoba, cool weather that delayed hatching, accompanied by good growing conditions, kept grasshopper damage to a minimum in most agricultural areas. Also, the fungus disease Empusa grylli reduced populations generally, and by as much as 50 per cent in the Carman and Gladstone districts, the areas of most severe outbreak. Infestation in general ranged from light to moderate. Areas of moderate infestation included Grosse Isle, Carman, St. Claude, McGregor, Gladstone, Douglas, ‘Treesbank, Oak Lake, and the southwest corner of the Province. Lighter infestations were common and widely distributed. M. bilituratus and C. pellucida were the principal species in light soil areas and M. bivittatus in the heavier soil areas. A reduction in the area infested and in the severity of infestations was forecast for 1960. In Eastern Canada grasshoppers were, as usual, of minor economic importance. JUNE BEETLES.—In British Columbia, larvae of Polyphylla perversa Csy. caused some damage in the lower Fraser Valley. In the Prairie Provinces no damage was reported. In Ontario, 1959 was a flight year for Phyllophaga spp., and defoliation of many deciduous trees was common but not serious. First-year larvae caused some late-season damage in central Ontario, possibly a result of rapid development, and prolonged mild weather in the fall. Second-year larvae of Brood C, limited to the Niagara Peninsula, caused little damage because of their small numbers. It was expected that, in 1960, white grub damage would be greater than usual east of the Rideau River and less than usual westward to Lake Huron. In Quebec, white grubs caused some severe damage to potatoes in the Ste.-Anne-de-la-Pocatiére district, and in Nova Scotia this crop was damaged in the Truro area. In New Brunswick, damage occurred commonly in the Fredericton area, and in Prince Edward Island up to 70 per cent of strawberry plants and potato tubers were damaged in some districts. SIX-SPOTTED LEAFHOPPER.—In Alberta this insect occurred only in small numbers, In Saskatchewan it was not reported, although a little aster yellows occurred on flax in north- eastern agricultural areas. In Manitoba the population reached a peak in August and the highest rate of transmission of yellows virus also occurred during this period. Percentage virus infection during the season ranged up to the following maximums in the hosts indicated: flax, 7; carrots, 15; onions, 2; celery, 1; lettuce, 100; aster, 100. Early-seeded flax escaped severe infection. Several weeds, including stinkweed, prickly lettuce, and flixweed, were commonly infected. WIREWORMS.—In the lower Fraser Valley, B.C., Agriotes obscurus (L.) caused 50 per cent mortality of young alfalfa seedlings in a field near Agassiz. No change was noted in its range. Near Ladner, B.C., potato seed was damaged by Agriotes sparsus Lec., Ctenicera lobata caricina (Germ.) and Hypolithus impressicollis (Mann.). Wireworms, mainly Ctenicera aeri- pennis (Kby.), caused light but widespread damage in the Peace River area, barley and flax being mainly affected. In the Kelowna area a planting of corn was severely damaged, and at Kamloops eggplants were attacked. In southern Alberta, wireworm damage averaged less than two per cent per field in cereals, 40 per cent of the fields examined showing damage. Some commercial plantings of sunflower were damaged. In the Turin area the sugar-beet wireworm was found in light infstation at four new locations. In Saskatchewan, wireworm damage was observed in 144 of 240 cereal crop fields examined. Thinning averaged 2.5 per cent per field. In 21 fields thinning ranged from 11 to 25 per cent; 20 of these were in western Saskatchewan, 19 containing wheat on summerfallow. In eastern Saskatchewan appreciable damage was found in only three fields. Data indicated that high soil moisture was beneficial to Hypolithus bicolor Esch. and detri- mental to Ctenicera aeripennis destructor (Brown). In Manitoba, potatoes were damaged in the Portage la Prairie and Souris areas. Dry condi- tions in western agricultural areas resulted in more wireworm damage than usual. In Ontario no wireworm damage was reported. In southwestern Quebec, wireworm populations increased rapidly in cultivated fields within a few years following grass seeding. Numbers ranged from 15 to 20 per square foot in some fields. The principal species involved were Agriotes mancus (Say), Dalopius pallidus Br., Hypolithus abbreviatus (Say), and Melanotus communis (Gyll.). Limonius sp. was found in cultivated fields in the Province, feeding on couch grass. In eastern Quebec a few reports were received of damage to vegetables and field potatoes. In the Atlantic Provinces, wireworms severely damaged potatoes in Westmorland County, N.B. A. mancus and H. abbreviatus were normally numerous in Annapolis, Kings, and Hants counties in Nova Scotia; Athous affinis Couper occurred in small numbers in the Digby area, and was found to be predacious on other wireworms. No new infestations of European species were found. In Prince Edward Island no damage was found, although Limonius pectoralis Lec. had fed on potatoes in 1957 and 1958. FIELD CROP INSECTS ALFALFA CATERPILLARS.—In the lower Fraser Valley, B.C., Colias ewrytheme Bdvl. threat- ened the canning pea crop, but was reduced by prompt control measures. In Manitoba this species and C. philodice Godt. occurred in small numbers on alfalfa. APHIDS.—In the lower Fraser Vailey, B.C., aphid species on grain included the English grain aphid in average numbers, Metapolophium dirhodum (Walk.), less abundant than usual, and Rhopalosiphum padi (L.) in markedly increased numbers, Proc. ent. Soc. Ont. 90 (1959)—1960 6] In the Prairie Provinces no outbreaks on grain were recorded. In Manitoba the corn leaf aphid and the pea aphid occurred in moderate numbers on barley and peas, causing noticeable damage in some fields of barley. The sweetclover aphid occurred in small numbers on sweet clover at Saskatoon, Sask., and in Manitoba. The turnip aphid infested rape at Codette, Sask. In Eastern Canada the corn leaf aphid developed in large numbers in southwestern Ontario, especially along Lake Erie, and in eastern Quebec, where barley was severely attacked. Contro] measures were necessary in both provinces. In New Brunswick small numbers developed in corn and grain. The English grain aphid was not a serious pest. In Ontario, high tempera- tures in July kept populations of the green peach aphid smaller than in 1958. BARLEY JOINT WORM.—In Prince Edward Island this insect was not a serious pest except in an area near Kensington, where 50 per cent of the barley was infested in stands of mixed barley and oats. The severe winter of 1958-59 was responsible for about 80 per cent mortality of the overwintering larvae in galls in the stubble. Normally the mortality is less than 10 per cent. CLOVER-INFESTING WEEVILS.—In Alberta, damage by the alfalfa weevil had become quite evident in fields in which the insect was first recorded. The average larval count per net sweep was 156. In Saskatchewan larvae were not as numerous in irrigated alfalfa in southwestern and south-central agricultural areas as they were in 1958. Populations remained small both here and in the dryland areas of southeastern Saskatchewan, and no noticeable spread occurred. The sweetclover weevil was not a serious pest in the Prairie Provinces or in Eastern Canada. Sitona scissifrons Say did not increase in Manitoba and ‘the clover head weevil was scarce in eastern Ontario. CLOVER SEED CHALCID.—Populations of this chalcid in red clover were larger than in 1957 and 1958 in the Ottawa, Ont., area, but damage to seed was light. CORN EARWORM.—In Saskatchewan this insect was not reported for the fourth consecu- tive year, and in Manitoba very few larvae were observed. In southern Ontario, outbreak numbers occurred, infestation being most severe in Essex County, where over 700 larvae per 100 plants were found in two fields of corn. Much damage was done in the Tecumseh, Exeter, Whitby, and Foxboro areas. Tomatoes were lightly infested in Essex and Kent counties in early August, and tobacco sucker growth in harvested fields was attacked in the fall. In ‘eastern Ontario, sweet corn was more heavily infested than usual. In eastern Quebec, popula- tions were about normal, but in southwestern areas the most severe infestation in seven years occurred on sweet corn, many crops being rejected at canning factories. In New Brunswick infestation was spotty, some corn fields being heavily infested while others were comparatively free of damage. In Nova Scotia, damage to corn was greater than in 1958. In Prince Edward Island no damage was observed. A CORN BILLBUG.—Sphenophorus sp. caused considerable damage to corn in southwestern Ontario, one field near Dresden requiring replanting. EUROPEAN CORN BORER.—Infestation in the southeast corner of Saskatchewan was the lightest since 1950. In Manitoba, too, the insect was generally scarce, infestation on corn averaging less than one per cent of the cobs in commercial plantings.. In Ontario, for the second year in succession, populations in the areas east of Toronto were larger than in the main husking-corn area of southwestern Ontario. Canning corn in the Whitby, Foxboro, and Deseronto areas was severely infested, but in Kent and Essex counties infestation was relatively light, partly because of drought conditions. In west-central areas, especially in Middlesex and Huron counties, much severe damage occurred. Average infestation in the five southwestern counties was 25 per cent, compared with 23 per cent in "1958, but the number of borers present was much greater than these figures indicated. Second-generation larvae were more numerous than in either 1957 or 1958. In the Ottawa area, numbers were well above average. In south- western Quebec, infestation of canning corn was the greatest in five years. A survey revealed an average of 27 per cent of the ears damaged at harvest. Average injury to stalks and ears was three times that of 1958 and the borer population was four times greater. In New Brunswick small numbers caused little damage. At Melita, Man., young corn was attacked by a false corn borer, Helotropha reniformis (Grt.). A EUROPEAN SKIPPER. — Adults of Adopaea lineolata Ochs. were very numerous from Toronto, Ont., westward to Lake Huron. The larvae feed on grass and, being green, are frequently not noticed, so that much damage is not reported. FALL ARMYWORM. — Larvae cf the fall armyworm, an unusual pest of corn, were numerous on this host in southwestern Quebec. FLAX BOLLWORM.—This insect was recorded in Alberta, but no damage was reported. In western agricultural areas of Saskatchewan the most severe infestation on record occurred. In west-central areas adults were observed in every field in which flax was in bloom. Larval counts numbered 700 to 800 per 25 net sweeps in the heavily infested areas, and over 40,000 acres were sprayed. In the Rosetown-Elrose and Eston areas, damage averaged 18.2 per cent and amounted to over 58 per cent in some fields. FLEA BEETLES.—In Alberta some flea beetles occurred on wheat and barley. In Saskat- chewan Phyllotreta sp. severely defoliated seedling rape at Meadow Lake, Prince Albert, and Proc. ent. Soc. Ont. 90 (1959)—1960 62 Canora, and was abundant at Saskatoon. In eastern Manitoba litthe damage was done to rape, but in the dry southwestern areas damage was severe. Many crops were sprayed and some plowed under. A GROUND BEETLE.—At Kindersley, Rosetown, and Wakaw, Sask., the stems of various seedling crops were girdled by Blapstius moestus Melsh. and the species was generally abundant in the Province. LEGUME-POLLINATING BEES.—In the Peace River district Bombus spp. were particu- larly numerous during the season. In the Wanless area of Manitoba one bumble bee species, Bombus terricola Kby., and two leafcutter species, Megachile frigida Sm. and M. inermis Prov., were the most important pollinators of alfalfa. PLANT BUGS.—In the lower Fraser Valley, B.C., Liocoris (=Lygus) spp. caused occasional damage. In the Peace River area L. wnctuosus Kelton and L, borealis Kelton were general in alfalfa seed-growing districts, but control measures were rarely applied. In northeastern agricultural areas of Saskatchewan these were the principal species in alfalfa seed crops, but they were less abundant than in the previous two or three years, particularly in continuous- control areas. The alfalfa plant bug was uniformly distributed in small numbers over the entire area, only occasionally becoming numerous. Plagiognathus medicagus Arrand occurred in small numbers in most fields and was of minor importance. Chlamydatus spp. also occurred. In Manitoba, populations of the tarnished plant bug were average and in the Ottawa River Valley, Ont., this species and the alfalfa plant bug were not as numerous oas usual in alfalfa and clovers. In the latter area normal numbers of Plagiognathus chrysanthemi (Wolff) were generally present in alfalfa, red clover, and birdsfoot trefoil. In eastern Quebec the tarnished plant bug was very numerous on clover, alfalfa, and potato. In Prince Edward Island it was not a serious pest. POTATO LEAFHOPPER.—This insect was unusually abundant in southwestern Ontario, causing considerable hopperburn on alfalfa. SOD WEBWORMS.—In coastal areas of British Columbia, populations continued to be large and at Dragon Lake, B.C., larvae were locally abundant. SPITTLEBUGS.—In southwestern Ontario the meadow spittlebug was more numerous than usual on first-year alfalfa. In the Ottawa, Ont., area it occurred in normal numbers, after large numbers in 1958. In eastern Quebec the insect was abundant. SUGAR. BEET INSECTS.—In Alberta, approximately 10,000 acres of sugar beets were treated for the sugar-beet root maggot. Nearly all untreated fields in the sandy soil of the Taber, Cranford, and Turin areas were infested. Large populations of the sugar-beet root aphid persisted in the light soil areas of southern Alberta, and damage by the leaf miner Pegomya betae (Curtis) was much lighter than in 1958. In Manitoba the sugar-beet maggot continued to increase its range, spreading farther into the light soil area west of Altona and Gretna, and for the first time occurred in general distribution in the Winkler area. The general severity of the infestation also increased ereatly. Over 2,400 acres were treated, compared with 906 acres in 1958. The leaf miner P. betae was a minor pest. In southwestern Ontario, isolated, severe infestations of the sugar-beet root aphid occurred in much of Kent County. SUNFLOWER INSECTS.—Although damage to sunfilowers was very light in Alberta, most of the insect pests affecting this crop in Manitoba were present. The fly Euarestoides finalis (Lw.) was present in greater numbers than normally found in Manitoba. Other pest species were Phalonia hospes (Wlshm.), Homoeosoma electellum (Hulst), Zygogramma ex- clamationis (F.), and a seed-infesting weevilfi probably Desmoris species. In Manitoba, the sunflower maggot was present in 93 per cent of the plants examined. The banded sunflower moth decreased in numbers, damaging about % of one per cent of the seeds examined. Para- sites of this species were abundant. The sunflower moth increased in numbers but remained sub-economic. Some damage was caused by the sunflower beetle, which was greatly reduced from the peak numbers of 1958. The painted-lady was present in small numbers causing little damage. The weevil Rhynchites aeneus (Boh.) occurred in usual numbers, mostly on volunteer sunflowers near 1958 plantings. E, finalis was normally numerous. Leafhoppers were about as numerous as in 1958 and little aster yellows occurred on sunfilowers. THRIPS.—In British Columbia Haplothrips niger (Osb.) developed major infestations in red-clover seed crops in the Dawson Creek and Fort St. John areas, but there was no economic damage. In agricultural areas of Saskatchewan the species averaged less than five thrips per flower raceme on red clover, causing itltle damage. Heavy infestations occurred in the Athabasca and Lac La Biche areas of northern Alberta. Thrips on barley were unimportant in Alberta and Limothrips denticornis Haliday was recorded for the first time in Saskatchewan, attacking barley at Hendon. In Manitoba, where it had been present for several years, it occurred on barley in large numbers in the Winnipeg, Baldur, Ste. Rose, and Beausejour districts, counts ranging up to 40 thrips per plant. TOBACCO INSECTS.—In southwestern Ontario the seed-corn maggot attacked flue-cured tobacco over a wider area and in greater numbers than in 1958. Damage was general and most severe in early planted crops. Hundreds of acres were replanted. Hornworms were more numerous and appeared earlier than usual. The tomato hornworm was the principal species, except in Essex County and the western part of Kent County, where the tobacco hornworm Proc. ent. Soc. Ont. 90 (1959)—1960 63 predominated. Large numbers of the cabbage looper developed on sucker growth in harvested tobacco fields. Hot weather reduced infestations of the green peach aphid to a minimum, The spotted cucumber beetle was numerous but not very injurious. Grasshoppers were very injurious to outer rows in some fields. In King’s County, N.S., the potato aphid and other aphid species were fairly numerous on flue-cured tobacco. A WEBWORM.--In Newfoundland Cnephasia virgaureana Treit. caused extensive damage to red clover in the St. John’s area. WHEAT PESTS.—In southern Alberta and Saskatchewan, large acreages of resistant Rescue and Chinook wheat kept populations of the wheat stem sawfly at a low level. The most severe damage occurred southeast of Lethbridge. In Manitoba, infestation _by this pest was generally light. At Winnipeg, Man., the wheat midge was about twice as injurious as in 1958 in test plots. The wheat stem maggot occurred in average numbers. VEGETABLE INSECTS ALFALFA LOOPER. — At Cloverdale, B.C., it was again necessary to use insecticides to control this insect on lettuce. APHIDS.—A mild winter and spring in British Columbia resulted in large populations of some aphids developing early in the season. The green peach aphid occurred generally in very large numbers on potato in the Province, causing unusual spread of leafroll virus, especially on the variety Netted Gem. Many plantings were severely affected and losses resulting from net necrosis in the tubers were high. In the lower Fraser Valley the potato aphid was unusually numerous, especially on weeds. The cabbage aphid remained scarce. The pea aphid was easily controlled. Myzus ascalonicus Doncaster and M. ornatus Laing caused only local damage. Cavariella aegopodit (Scop.) was somewhat injurious to carrots and dill, and C. archangelicae Scop. caused occasional damage to celery. In the interior, aphids damaged dill and carrots at Prince George, and were generally more injurious than usual on garden crops in the Kamloops area. In both Alberta and Saskatchewan, aphids were generally scarce, and, in the latter province, even less injurious than in 1958. In Manitoba, aphids were normally abundant except in eastern areas, where populations were above average. Moderate numbers of the pea aphid caused little damage. In southwestern and eastern areas of Ontario the pea aphid was less numerous than in 1958. In the former area populations were light to moderate and considerable spraying was done. In this area, too, the bean aphid caused only minor damage to lima beans, although it had been severe in Kent County in 1958, and the melon aphid caused extensive damage to market garden radish in the La Salle area. Light infestations of the cabbage aphid developed on crucifers in western Ontario, and in the Holland Marsh area numbers were above average, but definitely smaller than in 1958. In the latter area the green peach aphid was difficult to control on potatoes. In southwestern Quebec the pea aphid occurred in relatively light infestations on canning peas, and in eastern Quebec aphids were generally scarce on potatoes. In the Atlantic Provinces the pea aphid caused litthe economic damage to canning peas in New Brunswick and, although very numerous on this crop in Nova Scotia, it was well controlled. In New Brunswick aphids on potatoes developed some two weeks later than in 1958. Parasitism was light but predators were numerous. The green peach aphid was by far the most numerous species in check plots. In Nova Scotia, aphids appeared early on potatoes and were unusually numerous. In Prince Edward Island, potatoes in some localities were more heavily infested than usual, mainly by the potato aphid. ASPARAGUS BEETLES.—In Manitoba the spotted asparagus beetle was fairly numerous, but caused little damage. In southwestern Ontario, too, this species caused only minor damage, but the asparagus beetle caused light damage in the Chatham area and control measures were necessary in the Leamington region. In Quebec the spotted species was locally numerous in the vicinity of Quebec City. CATERPILLARS ON CRUCIFERS.—In the lower Fraser Valley, B.C., the cabbage looper was scarce, the imported cabbageworm less common than usual, and the diamondback moth present in normal numbers. In the Prairie Provinces the imported cabbageworm was less numerous than in 1958 in Saskatchewan and in normal numbers in Manitoba. The diamondback moth, very injurious to rape in Saskatchewan in 1958, was not reported in that province and occurred in light infestation in Manitoba. In Ontario the imported cabbageworm was very numerous and injurious in southwestern areas and in Hastings County. In the Ottawa area populations were larger than usual on early crops and about normal on late crops. The cabbage looper occurred in light outbreak numbers in the Holland Marsh, Ont., and for the first time in many years caused serious damage to non-cruciferous crops, namely, lettuce, celery, and spinach. Damage to crusifers was general in southwestern Ontario. In the Ottawa area a light outbreak occurred, resulting in severe damage to cabbage and cauliflower. How- ever, a polyhedral virus, not previously known in Canada, greatly reduced populations by mid-September. The diamondback moth was of minor importance in southwestern Ontario, but became fairly numerous on late cabbage in the Ottawa Valley. In Quebec the imported cabbageworm was more abundant and injurious than usual in nearly all areas and the dimondback moth caused appreciable damage to young crucifers. In New Brunswick the Proc. ent. Soc, Ont. 90 (1959)-——1960 64 imported cabbageworm and the cabbage looper were difficult to control in 100 acres of broccoli in Carleton and Sunbury counties. In Nova Scotia and Prince Edward Island, both the imported cabbageworm and the diamondback moth caused severe damage, much greater than in 1958 in the former province. The cabbage leoper was not important in Nova Scotia, but in Cape Breton County, N.S., the zebra caterpillar was injurious to cabbage. In New- foundland the diamondback moth was very injurious to rutabagas in western areas, and the imported cabbageworm occurred in small numbers throughout the Province. The purple-backed cabbageworm caused considerable defoliation of rutabagas generally, and a webworm, Cnephasia virgaureana ‘Treit., extensively damaged cabbage transplants. CARROT RUST FLY.—In the lower Fraser Valley, B.C., the carrot rust fly reappeared in commercial and domestic carrot crops at Agassiz and Cloverdale after five years of almost total absence. In Ontario, Quebec, and Nova Scotia, abundance was normal. In New Brunswick, damage to carrots and parsnips was generally light except in home gardens. In Prince Edward Island damage was moderate to severe in untreated carrots, and in Newfoundland the insect was very scarce. CARROT WEEVIL.—Infestation in the Holiand Marsh, Ont., continued to spread and in 1959 losses in early carrots ranged as high as 70 per cent in part of the Marsh. COLORADO POTATO BEETLE.—In Saskatchewan no infestation was found north of Saskatoon and damage in the south was negligible. In Manitoba numbers were normal. In practically all provinces in Eastern Canada a continued increase in numbers was noted on potatoes. In southwestern Ontario, light infestations occurred cn potato, and in the Ottawa area the insect occurred commonly on deadly nightshade. In Nova Scotia it was found at Scott’s Bay, where it had not been seen for ten years. A CRANE FLY.—In Cape Breton, N.S., Tipula paludosa Mg. was very scarce. In New- foundland light infestations throughout the Avalon Peninsula caused some damage to young crucifers, notably turnips. CUCUMBER BEETLES.—In southwestern Ontario the spotted cucumber beetle was more abundant than usual, causing some damage to Hubbard squash. The striped cucumber beetle, too, caused considerable damage to blossoms, foliage, and fruits of this host in this area. In New Brunwick, damage was light and in Prince Edward Island the insect was not observed. FLEA BEETLES.—In British Columbia, probably because of another mild winter, the tuber flea beetle was again abundant from Vancouver Island to the interior. Adults damaged potato foliage as soon as it emerged from the soil, but, except in many small gardens, the insect was fairly well controlled. Where not controlled, damage to tubers was severe. At Armstrong, B.C., adults were observed feeding on chickweed and couch grass. An infestation at Wynndel, B.C., was the most easterly record in the Province to date. At Armstrong, B.C., Phyllotreta albionica (Lec.) severely damaged cabbage. In Saskatchewan, damage by Phyllotreta spp. was the lightest since 1956. In Manitoba these, along with Psylliodes punctulata Melsh., caused some severe damage in the dry western areas of the Province. In southwestern Ontario and eastern Quebec the potato flea beetle was considerably more numerous and injurious than usual on potato and tomato. In New Brunswick and Nova Scotia, considerable severe damage was reported, but in Prince Edward Island the species was less numerous than usual. In the central part of the Ottawa River Valley, Phyllotreta cruciferae (Goeze) severely damaged seedling crucifers and growing turnips, but it was at the lowest population level since first recorded in Canada in 1954. In New Brunswick the striped flea beetle was observed on crucifers in the Maugerville-Sheffield area. LEAFHOPPERS.—In the Prairie Provinces the six-spotted leafhopper was scarce and little aster yellows occurred. In southern Ontario and Quebec it became quite abundant on lettuce, carrot, and celery, particularly in southwestern Ontario, where the incidence of aster yellows was very high on lettuce, but was not as widespread as in 1958 on carrots and celery. In Quebec, infection by the virus was generally light. In Nova Scotia this leafhopper was normally abundant, but in Prince Edward Island the incidence of the yellows virus ranged from 50 to 100 per cent on carrots and lettuce in market gardens. In Manitoba the potato leafhopper caused some hopperburn on potatoes. In southwestern and central Ontario large populations were very injurious to potatoes and beans. In the Ottawa area numbers were normal. In eastern Quebec, where the insect had been scarce for several years, large populations developed. MEXICAN BEAN BEETLE.—This beetle appeared to have increased in numbers on field beans in Lambton County, Ont. In southwestern Quebec small numbers were found in gardens at St. Antoine-Abbé, Franklin Centre, and: Havelock. ONION MAGGOT.—In the interior of British Columbia the onion maggot severely dam- aged onions grown from seed at Brocklehurst, Kamloops, Kelowna, Edgewood, and Cranbrook. A major reduction of the population in June, caused by a fungus disease, failed to prevent major losses. Very little damage occurred in Alberta and Saskatchewan, it being the lightest in the latter province since surveys were started in 1950. In Manitoba the pest was generally very injurious where not controlled. In Ontario large populations overwintered, ‘but the fungus disease, caused by Empusa muscae Cohn, combined with widespread use of insecticides to limit second and third broods; total losses were not heavy and an excellent onion crop was Proc. ent. Soc. Ont. 90 (1959)—1960 65 harvested. In Quebec and New Brunswick, losses were severe in home gardens, but the insect was fairly well controlled in market gardens. In Prince Edward Island, losses were light to moderate in gardens. PEA LEAF WEEVIL.—In coastal areas of British Columbia the pea leaf weevil commonly damaged various legumes. At Saanichton and Nanaimo the roots of clover were severely damaged by the larv ae, PEA MOTH. — In the lower Fraser Valley, B.C., pears were lightly infested. In New Brunswick and Prince Edward Island. damage was severe in home gardens and in areas where few peas were grown, but in Cemercie | plantings the insect was well controlled. PEPPER M AGGOT. —Several plantings of sweet and pimento peppers in the vicinity of Leamington, Ont., were moderately to severely damaged by larvae of Zonosema electa (Say). This was the first record of the species in Canada, but it was believed to have been present at least since 1956. PLANT BUGS.--The tarnished plant bug caused moderate damage to potatoes in Quebec, light damage in Nova Scotia, where it was less numerous than in 1958, and severe damage in New Brunswick and Newfoundland. POTATO SCAB GNAT.—Larvae of Pnyxia scabiei (Hopg.) damaged potato tubers in several areas of eastern Quebec. RED TURNIP BEETLE.—In the Peace River area of British Columbia the red turnip beetle extensively damaged various crucifers. In northern Saskatchewan rape was lightly dam- aged in several areas and severely damaged at Hudson Bay. ROOT MAGGOTS IN CRUCIFERS.—Near Victoria, B.C., recommended insecticides failed to control the cabbage maggot on cruciferous hosts. In the interior of the Province, turnips were commonly damaged by the turnip maggot where control measures were neglected. In Saskatchewan this species caused the least injury since 1950 and Hylemya planipalpus (Stein) was scarce. In Manitoba the turnip maggot occurred in large numbers and the cabbage maggot caused increased damage to rape near Winnipeg. In Ontario the cabbage maggot was very injurious in home gardens and at La Salle caused extensive losses in market gardens. In the Ottawa area populations were below average, but damage to early cabbage was accentuated by drought conditions. In Quebec the cabbage maggot ‘severely damaged market turnips in the Quebec City area and was generaily a major pest of crucifers in the spring. In King’s County, N.B., it caused over 90 per cent loss in untreated early cabbage, but in the Mauger- ville-Sheffield area damage was only moderate. Turnips were severely injured by the turnip maggot in many areas. In the Annapolis Valley, N.S., the cabbage maggot severely injured turnips. In Prince Edward Island, damage by this insect. was generally severe in light soil areas. Rutabagas in heavier soil areas suffered the most. severe damage since 1954. In Newfoundland the cabbage maggot was moderately abundant and caused some severe damage to cabbage and turnips. SEED-CORN MAGGOT.—At Yorkton, Sask., the seed-corn maggot occurred in decaying carrots. In Ontario it was injurious mainly to tobacco seedlings. In Elgin County a large planting of potatoes was severely injured in early May. The widespread use of seed dressing in the Province prevented major losses in beans, corn, peas, and cucurbits. In the lower St. Lawrence Valley, Que., infestation was generally light. In Nova Scotia normal abundance was reported. In Prince Edward Island the insect was not generally abundant, but caused some severe local damage. SLUGS.—In the lower Fraser Valley, B.C., slugs were occasional local pests, but in the Okanagan Valley and central areas of the Province they occurred in gardens in large numbers. In Alberta and Saskatchewan they were of little importance, but in some areas of Manitoba they were particularly injurious as a result of heavy precipitation. In southwestern Ontario, damage was less than in 1958, the weather being hot and dry. In the Nicolet, Que., area and in Kings County, N.S., potatoes were considerably injured. In Prince Edward Island slugs were numerous, but less so than in 1958. In Newfoundland they were generally troublesome in gardens and lawns throughout the season. SPINACH LEAF MINER.—This leaf miner was again a common pest of spinach and red beets and, to a lesser extent, of sugar beets in southwestern Ontario. STEM BORERS.—In southwestern Quebec the potato stem borer caused some damage to sweet corn, particularly to young plants. Occurrence on this host was considered unusual. In eastern Quebec the insect was much less numerous than in previous years. In New Brunwick, rhubarb and a planting of seed potatoes were extensively damaged in the Keswick area. In Nova Scotia the insect caused some damage, but was much. less numerous than in 1958. In eastern areas of Newfoundland light infestations occurred commonly on potatoes. In south- western Ontario the squash vine borer, an increasingly serious pest, was very abundant, causing considerable damage to squash and pumpkin. A SYMPHILID. — In the Victoria and Courtenay areas of Vancouver Island, B.C., a symphilid, Scutigerella sp., prob. palmonii Michenbacher, was found for the first time causing damage to commercial plantings of beets, carrots, lettuce, and cabbage. THRIPS.—At Terrace, B.C., the onion thrips caused considerable damage to several vari- eties of onions, but the variety Evergreen table white was not attacked. In southwestern Proc. ent. Soc. Ont. 90 (19529)—1960 66 Ontario, populations were about normal on onion. It occurred commonly on cabbage, also, but its economic status on this host was not known. FRUIT INSECTS APHIDS.—In the interior of British Columbia Aphis pomi DeG. continued to be trouble- some in most orchards. In Ontario it was less numerous than usual and in Quebec it caused minor injury, although control measures were required in many apple orchards. In New Brunswick infestation was generally heavier than in 1958 and in Nova Scotia aphids caused little damage in orchards although appreciable numbers developed on new growth late in the season. For the first time in many year Sappaphis plantaginea (Pass.)'was evident in many orchards in the interior of British Columbia and required control measures in the South Okanagan. In Nor- folk County, Ont., it was almost absent in orchards that had been fairly heavily infested in 1958. In Quebec it continued to be an important pest on Cortland apples and in the Atlantic Provinces injury was generally light. In the interior of British Columbia biological control of the woolly apple aphid was very effective. In Nova Scotia small early-season populations of this species later increased to light infestation in many orchards. Rhopalosiphum fitchii (Sand.) was the most numerous aphid species in the spring, but numbers were average... In British Columbia the green peach aphid was much more injurious than in 1958, especially in the Okanagan Valley; the black cherry aphid, too, had increased noticeably, and the thistle aphid and mealy plum aphid severely infested unsprayed prune trees. In coastal areas of British Columbia, minor aphid infestations on strawberry involved Myzus ascalonicus Doncaster, Aulacorthum solani (Kltb.) in screenhouses at Saanichton, and Metapolophium sp., probably new. In Nova Scotia Pentatrichopus spp. were numerous on untreated strawberry plants, but aphid populations in general were about average. In Ontario, aphids attacking fruit trees were generally less abundant than usual. APPLE (AND BLUEBERRY) MAGGOT.—In Ontario a few severe infestations on apple were reported, but control was satisfactory in most commercial orchards. In the Niagara Peninsula the insect continued to be a troublesome pest of prune. In eastern Quebec it was a major pest in many apple orchards, but in southwestern Quebec and New Brunswick infestation generally was greatly reduced, even phenomenally so in the latter Province. In Nova Scotia it was less numerous and injurious than in 1958, and in Prince Edward Island it was of minor importance. Infestation of blueberry was generally light in New Brunswick, Nova Scotia, and Prince Edward Island, although berries from some untreated areas in Nova Scotia, notably Shelburne County, were heavily infested. APPLE MEALYBUG.—Injury by this mealybug was much lighter than in 1958 in New Brunswick and no damage was reported in Nova Scotia. | APPLE SEED CHALCID.—In New Brunswick this insect occurred in most apple orchards, heavily infesting neglected trees. In Nova Scotia it was less numerous than usual, injuring very little fruit. APPLE SUCKER.—In Nova Scotia the apple sucker was present in most orchards, but required spraying in only a few. CANKERWORMS.—In Nova Scotia, cankerworms may not have been as numerous as in recent years, but it was necessary to apply insecticides to protect some orchards from the fall cankerworm, and others from the winter moth. CASEBEARERS.—Populations of the pistol casebearer, Colephora anatipennella (Hbn.), declined in some orchards in Nova Scotia, but in some areas, particularly in west Hants County, it was unusually abundant. The cigar casebearer, C. serrateala (L.), was less numerous” than the pistol casebearer and there seemed to be little variation in its numbers from those of previous years. CHERRY FRUIT ee -4IThe black cherry fr uit fly was less injurious than in 1958 in the Kootenay Valley, CODLING Ones the interior of British Columbia, prolonged cool weather which’ retarded early moth development was followed by hot weather and rapid growth. Orchard crops were threatened for a time, but another, cool period assisted materially in effecting satisfactory control. In all apple-growing areas of Ontario except the St. Lawrence Valley, weather conditions favourable to development of the codling moth contributed to more than the usual amount of injury, especially by second-generation larvae. In the Niagara Peninsula, injury to Bartlett pears was the most severe in several years. Conditions in the apple-growing areas of southern Quebec were very similar to those of Ontario and injury was above average. In New Brunswick greatly reduced populations caused little severe injury. In Nova Scotia a survey of 80 commercial apple orchards, generally distributed throughout the Annapolis Valley, revealed that 2.6 per cent of the apples were injured by the codling moth. Although this was the smallest amount of codling moth injury recorded in more than ten years, it accounted for nearly half of the insect injuries. In Prince Edward Island this pest occurred generally in very small numbers. CRANBERRY FRUITWORM. — Considerable fruitworm injury in some bogs in Nova Scotia was probably accentuated by a small crop, reduced by spring’ and fall frosts. The insect caused little damage in Prince Edward Island. Proc, ent, Soc, Ont. 90 (1959)—1960 67 CURCULIONIDS.—In Ontario, excepting Essex county, the plum curculio caused consid- erably more injury to apples and stone fruits than in 1958. In southwestern Quebec normal numbers moderately infested scattered orchards and in eastern Quebec small infestations caused little injury. In New Brunswick, populations were greatly reduced. In British Columbia, dam- age to strawberry by Brachyrhinus spp. was considerable in the Vernon and Salmon Arm districts. Damage to strawberry in eastern Quebec, New Brunswick, and Nova Scotia was unusually light. Damage to strawberry in Eastern Canada by Anthonomus signatus' Say was generally light, but in Nova Scotia it caused serious loss of buds in some raspberry plantings. CURRANT FRUIT FLY.—This insect developed in normal numbers on currant and goose- berry, most records of damage originating in the Prairie Provinces. CUTWORMS. — Cutworm damage to blueberry in New Brunswick was generally light, except in the Tower Hill district, where increased numbers caused some injury. EYE-SPOTTED BUD MOTH.—Damage in commercial orchards throughout the country was generally light. However, in Nova Scotia, following several years of unusual scarcity, a definite increase was noted and injury (1.4 per cent of fruit in 80 orchards) was the greatest since 1952. Considerable damage occurred in most poorly sprayed orchards in all areas. FRUIT TREE BORERS.—In the interior of British Columbia the peach twig borer per- sisted in small numbers in most peach and apricot orchards and the peach tree borer injured peach, apricot, and prune trees in neglected orchards. In Ontario, infestations of the latter insect and the lesser peach tree borer were lighter than in recent years in commercial orchards in Essel County. In unsprayed orchards in both this county and the Niagara Peninsula. infestation persisted at a high level, especially on peach trees suffering from winter injury. GRAPE BERRY MOTH.—Most vineyards in Ontario were free of serious infestations of this pest. ERAPE PHYLLOXERA.—In Ontario the root-feeding form of this insect was found in almost all vineyards examined, infestations varying from a trace to 100 per cent of the plants. However, no conclusive evidence was obtained that the grape crop was appreciably affected. GREEN FRUITWORMS.—The cherry fruitworm was not reported in British Columbia, and in Nova Scotia Lithophane spp. and Xylena spp. remained scarce. IMPORTED CURRANTWORM.—The only damage reported west of the Atlantic Pro- vinces involved several gardens at Kamloops, B.C. In the former area, damage to currant and gooseberry was general, ranging from moderate to severe. LEAFHOPPERS.—On Vancouver Island and in the lower Fraser Valley, B.C., Typhlocyba spp., the bramble leafhopper, and the rose leafhopper continued to be abundant on cane fruits. In the Lulu Island area Macropsis fuscula (Zett.) severely infested loganberry, and specimens were taken on raspberry and blackberry as far east as Abbotsford and Yarrow. In the interior of British Columbia, leafhoppers were numerous on unsprayed apple and prune. In southwestern Quebec the buffalo treehopper and three allied species were common in young apple orchards. In Nova Scotia “green petal” virus of strawberry, spread by Macrosteles fascifrons (Stal), was of minor importance, and the white apple leafhopper was generally less numerous than in 1958. LEAF MINERS.—In eastern Quebec, infestations of Lithocolletis malimalifoliella Braun were general and more severe than in previous years. In Nova Scotia, too, the insect was unusually abundant in many orchards, but in New Brunswick it was not a problem. LEAF ROLLERS.—In the interior of British Columbia the fruit tree leaf roller was less important than in 1957 and 1958. In the Niagara Peninsula and Norfolk County, Ont., infestation by the strawberry leaf roller remained generally light for the second successive year. In apple orchards of Ontario the red-banded leaf roller was comparatively scarce for the second successive year, and in southwestern Quebec it was scarce, except at St. Hilaire where 15 per cent of the crop was injured. Also, in Quebec, Pandemis limitata (Rob.) and the fruit tree leaf roller were of little importance, and Pseudexentera mali Free. caused light damage at Rougemont, Abbotsford, and Frelighsburg. In. Nova Scotia the gray-banded leaf roller and other species remained at low population levels on apple, and Sparaganothis sulfureana Clem. caused considerable defoliation of blueberry in Colchester, Cumberland, and Inverness counties. MITES.—In the interior of British Columbia Tetranychus mcdanieli McG. continued to be the most injurious orchard mite. A resistant strain of the European red mite was particu- larly injurious in the Penticton district. Rust mites and the two-spotted spider mite were less noticeable than in 1958 on tree fruits, but the pear leaf blister mite was rather more injurious than in 1957 and 1958. The cyclamen mite attacked strawberry plants in the Creston and lower Fraser Valley areas. The yellow spider mite, the pear leaf blister mite, and Sryobia arborea M. & A. were minor pests. At Kindersley, Sask., and in Manitoba, raspberry foliage was attacked by mites, T. mcdanieli in the latter case. In Ontario severe infestations of the European red mite developed in mid-summer on apple, peach, and plum as a result of hot, dry weather. Control on plum was especially difficult, and increasing numbers on Bartlett pear during recent years resulted in much injury. The peach silver mite was exceptionally numerous in some peach orchards where organic fungicides had replaced sulphur. The two- spotted spider mite generally caused little damage. In southwestern Quebec the European red mite was the most prevalent pest of apple in all districts, but in eastern Quebec it caused Proc. ent. Soc. Ont: 90 (1959)—-1960 68 little damage. The two-spotted spider mite was more abundant than usual on apple in southwestern districts, but its status was far below that of the European red mie. In the Atlantic Provinces the European red mite increased in numbers and damage caused, especially in commercial orchards where miticide resistance had developed. The pear leaf blister mite was no more abundant than usual in Nova Scotia and, although widely distributed on pear in Prince Edward Island, it was less injurious than usual. In Nova Scotia the cyclamen mite and the two-spotted spider mite occurred only in small numbers on strawberry. ORIENTAL FRUIT MOTH.—Trap records over a three-year period indicated that this pest had not become established in the Okanagan Valley, B.C. In the Niagara Peninsula, Ont., twig injury by the first generation was greater than usual, but injury by the second generation in mid-summer was less than usual in both twigs and fruit. Except in one or two severely injured orchards, peaches harvested before the Elberta variety were comparatively lightly infested by third-generation larvae. However, Elberta peaches at harvest in mid-September had more larvae, many of them very small, than for the previous 10 years, injury ranging up to 20 per cent in some orchards. This was a result of exceptionally hot weather in late August and early September, favouring the development of a fourth brood of larvae. In Essex County, infestation and injury were less than in 1958, and Elberta peaches were harvested early enough to escape most of the fourth-generation attack. Kieffer pears were moderately infested as a result of egg-laying in late September and early October. PEAR PSYLLA.—In the Okanagan and Similkameen valleys, B.C., the pear psylla was the most important orchard pest in 1959. In the Niagara Peninsula, Ont., infestation by the first generation was somewhat heavier and more difficult to control than usual, but after mid-July this insect was unusually scarce in most pear orchards. In Nova Scotia, infestations were generally light. PEAR-SLUGS.—In the interior of British Columbia the California pear-slug caused slight injury to pear in the Oliver-Osoyoos district, and the pear-slug continued to be of minor importance on pear and cherry. In Prince Edward Island the pear-slug occurred as a minor est. PLANT BUGS.—In British Columbia Liocoris spp. were difficult to control in a few peach orchards in the Oliver-Osoyoos district. In Ontario, damage to peach by the tarnished plant bug was very light. In Nova Scotia there were more reports than usual of Lygus (Neolygus) communis novascotiensis Knight, but the number of infested orchards remained very small. RASPBERRY CANE BORERS.—Oberea sp., mainly affinis Leng, was in the second-year larval stage in eastern Ontario and occurred commonly. In New Brunswick, cane borer damage was generally greater than in 1958, but in Nova Scotia it was of minor importance. RASPBERRY CANE MAGGOT.—Infestation in coastal areas of British Columbia was light. In Nova Scotia the insect was found in a small planting of raspberry in ‘Truro, the first record in the Province. RASPBERRY ROOT BORER.—In British Columbia this insect continued to be a serious pest of loganberry and raspberry on Vancouver Island and in the lower Fraser Valley. In Saskatchewan, records from St. Gregor and Saskatoon were the first since 1955. RASPBERRY SAWFLY.—Infestation was heavy late in the season in coastal areas of British Columbia. ROSE CHAFER.—Adults were scarce in Ontario and caused little damage to grape and peach. A SAP-FEEDING BEETLE. — In Elgin and Lambton counties in Ontario, adults of Glischrochilus quadrisignatus (Say) caused severe damage to the ripening fruit of raspberry. Some growers considered discontinuing production. SCALE INSECTS.—In the interior of British Columbia the oystershell scale continued to be unimportant in commercial orchards, but was numerous on abandoned apple trees. In New Brunswick and Nova Scotia, populations remained small and damage was light. The San Jose scale, too, continued to be of little importance in British Columbia and Ontario, although considerable numbers developed in one orchard in Norfolk County, Ont. In the interior of British Columbia Lecanium spp. were even less injurious to peach and apricot than in 1958. In Ontario, infestations of L. coryli (L.) and L. cerasifex Fitch caused little injury to peach, apple, and plum except in a few peach orchards in Essex County and several apple orchards in Norfolk County. In Nova Scotia L. cerasifex was abundant in a few orchards, seriously damaging some crops. ‘The cottony peach scale was a very minor pest in British Columbia and Ontario, a great reduction on peach being evident in the latter - province. STINK BUGS.—In British Columbia, stink bugs were apparently less injurious to stone fruits than in 1958. | TENT CATERPILLARS.—In the vicinity of Saskatoon, Sask., Malacosoma spp. were less abundant than usual. In Ontario they were more numerous than in 1958, but no outbreaks were reported. In the Atlantic Provinces, populations were small and damage light. In New Brunswick the ugly-nest caterpillar caused minor defoliation of wild cherry and apple. In Proc. ent. Soc. Ont. 90 (1959)—1960 69 | Sea the lower Fraser Valley and Okanagan Valleys, B.C., and in Ontario, and western Quebec, the fall webworm was much more numerous than usual: in Nova Scotia it occurred in small numbers. THRIPS.—In British Columbia no “‘pansy spot” injury on apple was reported, indicating a scarcity of the thrips Frankliniella occidentalis (Perg.). In New Brunswich F. vaccinia Morgan caused little damage, but in Nova Scotia it, along with Taeniothrips vaccinophilus Hood, caused considerable injury in scattered blueberry fields throughout the Province. RED-HUMPED CATERPILLAR.—This usually rare insect was reported in several areas of Nova Scotia. YELLOW-NECKED CATERPILLAR.—In the Oliver-Osoyoos area of British Columbia this insect continued to cause some damage in fruit orchards. In Nova Scotia it was less scarce than usual and fed to some extent on blueberry. PREDATORS OF APPLE PESTS.—In Nova Scotia, predators were generally numerous in the orchards. Anthocoris musculus (Say) was present in moderate numbers in most orchards. The mullein leaf bug Campylomma verbasci (Mey.) was generally more abundant than usual. Haplothrips faurei Hood built up to moderate numbers by the end of the season. Pentatomids, coccinellids, and chrysopids were moderately plentiful. INSECTS AFFECTING GREENHOUSE AND ORNAMENTAL-~ PLANTS APHIDS.—On Vancouver Island, B.C., the green peach aphid and the potato aphid heavily infested crops of Digitalis, and the rose aphid ‘damaged. holly in commercial plantings. In the lower Fraser Valley the rose aphid was generally injurious to roses. In Winnipeg, Man., Myzocallis punctata (Monell) occurred in very large numbers on oak. In southwestern Ontario, aphids generally were not very troublesome on ornamentals, but in southern Quebec they were reported to be abundant. EIGHT-SPOTTED FORESTER.—At St. Jean, Que., this insect was abundant on Virginia creeper. EUROPEAN PINE SHOOT MOTH.—Severe infestations occurred on Jack pine and Scots pine in St. John’s, Nfld., and vicinity. FALL WEBWORM.--Tents of this webworm were very numerous on shade trees in the lower Fraser and Okanagan valleys, B.C,, and in southern areas of Ontario and Quebec. FLEA BEETLES. — An unidentified species of flea beetle heavily infested pansy at Fredericton, N.B. GREENHOUSE WHITEFLY.—Cucumbers in many greenhouses in Ontario were attacked by this insect. LEAF BEETLES. — Weeping willow was attacked at Little Fort, B.C., by Calligrapha multipunctata bigsbyana (Kby.), and at St. Jean, Que., by the imported willow leaf beetle. LEAF MINERS.—The lilac leaf miner was a common pest in Eastern Canada, but in eastern Quebec the population was at an unusually low level. In Prince Edward Island it was less numerous than usual. The birch leaf miner occurred commonly on ornamental birch in southwestern Ontario and southern Quebec. LOCUST BORER.—Ornamental black locust at St. Jean, Que., was heavily infested by this borer. MITES.—A survey of holly plantings on Vancouver Island revealed general damage by an unfamiliar species of mite, which on identification, proved to be Acaricalis hederae K. The species occurs on holly in Oregon and on ivy in California, but it had not previously been recorded in Canada. Another new mite record involved the species Tyrophagus longior (Gervais), which damaged greenhouse cucumbers at Victoria, B.C. This species infests foodstuffs and may cause intestinal myiasis. It has been found occasionally in North America. The bulb mite, Rhizoglyphu echinopus (F. & R.), was not uncommon in the lower Fraser Valley. Roses, daffodils, and chrysanthemums were infested by mites in various areas. The two-spotted spider mite commonly attacked ornamental shrubs and flowers in eastern Quebec, and the maple bladder-gall mite disfigured maple in Ontario and Quebec. MOUNTAINASH SAWELY. — This sawfly was very injurious to imported ornamental mountain ash in many urban areas in Eastern Canada. A NEMATODE.—The nematode Meloidogyne incognita (Kofoid & White) Chitwood, 1949 occurred on the roots of tomato in a greenhouse in the lower Fraser Valley, B.C. SATIN MOTH.—Infestations in Kamloops and the Okanagan Valley, B.C., were noticeably lighter than in 1958. The insect was not reported in Quebec. SCALE INSECTS.—At Kelowna, B.C., and in southwestern Ontario, the juniper scale was injurious to ornamental cedars. In western areas of Manitoba the pine needle scale was more abundant than usual on ornamental spruce and pine. In the Chatham, Ont., area the cottony maple scale was common, causing some injury to soft maple. In St. John County, N.B.;. the hemispherical scale was a pest of oleander, and in Prince Edward Island the oystershell scale was prevalent on shade trees and shrubs, severely injuring some. SPRUCE BUDWORM.—This budworm was considerably more injurious than in recent years to white spruce in eastern Ontario. In eastern Quebec and Prince Edward Island, popula- tions were generally smaller than usual. Proc. ent. Soc. Ont. 90 (1959)—1960 70 WEBWORMS.—The webworm Swammerdamia caesiella Hbn. again occurred in scattered infestations on Japanese plum in the eastern half of the Niagara "Peninsula, and S$. lutarea Haw. severely attacked hawthorn hedges, shrubs, and trees at St. John’s, Nfld. INSECTS ATTACKING MAMMALS AND BIRDS BAT BUG.—A bat bug, probably Cimex pilosellus (Horv.), was reported from Regina, Sask. BED BUG.—Reports of bed bug infestations, although not numerous, indicated widespread distribution and continued persistence, especially in work camps and in low standard urban housing areas. BLACK FLIES.—In the Bulkley Valley, Vanderhoof, and Lillooet areas of British Columbia, Simulium sp. caused considerable annoyance to cattle. Humans were attacked in many areas of the Province. In central Saskatchewan Simulium arcticum Mall. occurred in minor outbreaks. In the Saskatoon area this species and S. grisewm Coq. occurred commonly on horses, the latter species appearing during the last two weeks of June, much earlier than usual. S. venustum Say was less numerous than usual in many areas of the Province. In western Manitoba low water levels greatly reduced breeding areas. In eastern Ontario high water levels contributed to large black fly populations and much annoyance to livestock during spring and early summer. BLACK WIDOW SPIDER.—Reports of this spider were less numerous than usual in the interior of British Columbia. At Kamloops most inquiries originated in a new building area. A few reports were received at Lethbridge, Alta. BLOW FLIES AND FLESH FLIES.—In Kamloops and Vernon, B.C., several cases of myiasis in kittens and puppies were caused by Wohlfahrtia opaca (Coq.). In Alberta, species of this genus attacked infants at Edmonton, Grand Prairie, and Lethbridge, causing abscesses on face, neck, and chest, and at Regina, Sask., a severe infestation occurred on mink kits. In Newfoundland Phaenicia sericata (Mg.) severely attacked sheep on the Avalon Peninsula. CATTLE WARBLES.--In the Kamloops, B.C., area, adverse weather conditions reduced populations of Hypoderma spp. from those of 1958 by 15 to 20 per cent. In the Peace River district and central areas of the Province, infestation caused some concern. Few inquiries were received from the Prairie Provinces. In Ontario and Quebec organized control kept populations at a Minimum. In Newfoundland light infestation occurred in the Codroy Valley. DEER FLIES.—Chrysops aestuans Wulp was reported in southern Saskatchewan, and in eastern Ontario some 12 species of Chrysops were very numerous in late summer, FLEAS.—Ctenocephalides spp., major household pests in late summer and fall, were com- monly reported from coast to coast and were unusually numerous in Prince Edward Island. One report of fleas infesting mink was received from northern Alberta. A severe infestation of the European chicken flea was reported from Hull, Que. HORN FLY.—In eastern Ontario the horn fly was more numerous than usual, but else- where in the country abundance was apparently normal. LICE.—In British Columbia unusually heavy infestations of Haematopinus eurysternus (Nitz.) were observed on cattle during the fall season. At the zoo in Edmonton, Alta., a louse, Piagetella sp., was recorded for the first time in the Province when it was found living in the pouch of a native pelican. In the Prairie Provinces, cattle lice were occasionally reported. In Ontario and Quebec, lice on humans continued to be a problem in work camps in northern areas and in some low-income families in cities. The cat louse was reported in southern British Columbia. MOSQUITOES.—In the Kamloops, B.C., area, a large population of snow-pool mosquitoes was well controlled and the population of flood water species was small. In central British Columbia and the Okanagan Valley, mosquitoes caused a great deal of annoyance. In Saskat- chewan populations were small. In eastern Manitoba and the Winnipeg area, Aedes spp. were abundant following heavy June rains. In eastern Ontario a succession of species persisted in large numbers throughout the season, the early summer populations being very annoying to livestock, wild life, and man. In Prince Edward Island, mosquitoes were more abundant, and in Newfoundland less abundant, than usual, A MUSCID.—The so-called “face fly’, Musca autumnalis Deg., recently introduced into America, has spread rapidly from the east coast westward and is now well established in Ontario and Quebec. In the former province it had become numerous enough in 1959 in some areas to cause cattle to seek shelter during the day. In Russia this fly is an intermediate host for Thelazia rhodezii, a mammalian eyeworm that causes pink eye. STABLE FLY AND TABANIDS.—In Kent County, Ont., the stable fly occurred in above average numbers for the second consecutive season, greatly annoying livestock and humans. In at least two areas of southwestern Ontario, the horse fly Tabanus calens (Linne) (=T. giganteus DeG.) caused considerable annoyance to cattle. In eastern Ontario Tabanus spp. were exceptionally numerous and annoying to stock. TICKS.—In British Columbia a herd of 200 yearling calves on a ranch at Monte Creek was heavily infested with Dermacentor andersoni Stiles and three were paralysed. This was the first record of the tick on the ranch in its 80-year history, At Stump Lake three cattle were Proc. ent. Soc. Ont. 90 (1959)—1960 ql paralysed. In general, tick populations were considered about normal. In Alberta this tick was recorded only once when it attached to a child at Calgary. In Saskatchewan it occurred ~ on man at Dodsland and Assiniboia. At Jura, north of Princeton, B.C., the ear tick, Otobius megnini (Dugés), caused the death of.a yearling heifer and may have been associated with previous casualties where symptoms were similar. The species occurs commonly on mule-deer and elk. In British Columbia Dermacentor albipictus (Pack.) was numerous on moose and attacked cattle in the Dawson Creek area. A specimen removed from a child was the only record from Alberta. Dermacentor variabilis (Say) occurred on a dog at Kelso, Sask., and in Manitoba was increasingly troublesome to campers. In Ontario and Quebec Ixodes cookei Pack. was occasionally a pest of man and pet animals. At Ottawa, Ont., reports of the brown dog tick were comparatively scarce. WASPS AND HORNETS.—These annoying annual pests were seers) reported. In the Okanagan Valley, B.C., many bee hives were robbed. HOUSEHOLD INSECTS ANTS.—Ants were genarally troublesome pests in buildings, lawns, and gardens. Campo: notus spp. was commonly reported in British Columbia, Ontario, Quebec. and Newfoundland. The pharaoh ant was an increasingly important pest in restaurants, dwellings, and industrial buildings in most of Eastern Canada. Lasius sitkaensis Perg. was reported from Vancouver, B.C., and the pavement ant, Tetramorium caespitum (L.), from Windsor, Ont. BOOKLOUSE.—The booklouse was more troublesome than usual at Ottawa during the fall, probably because of high humidity resulting from frequent rains. BOXELDER BUG.—This insect was conspicuous by a complete absence of reports at Ottawa during the season. Late reports indicated appreciable numbers in the Okanagan Valley, B.C., and some infestation in southern Alberta and Saskatchewan. This situation followed a season of unusual scarcity from Manitoba eastward in 1958. CARPET BEETLES AND OTHER DERMESTIDS.—Carpet beetles were still the most commonly reported of the household pests and were more numerous than usual in Ontario. Anthrenus scrophulariae (L.) and A. verbasci (L.) predominated in coastal areas of British Columbia, and the former was the principal species in the Atlantic Provinces. In the Prairie Provinces, Ontario, and Quebec, Attagenus piceus (Oliv.) was the major species, infestations outnumbering those of 4. scrophulariae by about four to one in the latter two provinces. Only one iesiaitlonn of A. verbasci, at Windsor, Ont., was recorded east of British Columbia. The larder beetle, generally distributed, has apparently increased in importance in some areas in recent years. At Ottawa Anthrnus museorum (L.) occurred in a dwelling. CLOTHES MOTHS.—Although generally reported from coast to coast, inquiries concern- ing clothes moths were far less numerous than they were prior to the recent upsurge in insect- icide research. Increased dry-cleaning facilities, too, have contributed considerably to_ come! of these pests. In most areas the webbing clothes moth was the major species. CLUSTER FLY.—Less numerous than usual in Eastern Canada in 1958, this insect was again seldom reported, probably a result of subnormal precipitation in many areas, notably in Ontario and Quebec during May and June, the normal larval establishment period. The species is not an important pest in most of Western Canada. COCKROACHES.—The brown-banded roach was recorded for the first time as an infesta- tion in Manitoba, where it occurred in an apartment in Winnipeg. In Edmonton, Alta., one infestation was reported, and in Ontario it continued to spread and is now known to be present in many urban centres in central and eastern areas of the Province. Throughout Canada the German cockroach continued to be a major pest and by far the most common species. Parcoblatta pennsylvanica (DeG.) occurred commonly in cottages and motels in the Lauren- tians. The oriental cockroach was found in Calgary and Nampa, Alta., and in Quebec. The American cockroach was reported from Lethbridge, Alta. CRICKETS.—The field cricket commonly invaded apartments and dwellings in many areas. Ceuthophilus sp. was an occasional pest in basements, and the house cricket was reported from Saskatchewan; Ottawa, Ont.; and Montreal, Que. EUROPEAN EARWIG.--Single infestations were reported from Vancouver, B.C., and Montreal, Que., but in St. John’s, Nfld., the insect was a rapidly increasing nuisance. HOUSE CTNTIPEDE.—This indoor predator of insects was recorded from Calgary, Alta.; Ottawa, Toronto, and Kingston, Ont.; and Lachine, Que. LESSER WAX MOTH (Achroia grisella (F.)).—The lesser wax moth was recorded fan the first time in Ontario when large numbers infested bee colonies in the walls of a dwelling at Winchester. Previous Canadian records involved Covey Hill, Que., in 1912, and the lower mainland of British Columbia in 1930. HOUSE FLY.—Although seldom reported, the house fly is believed to be numerous where suitable breeding conditions exist, and the object of persistent and widespread control measures. MANURE FLIES.—The first records of Leptocera sp. in buildings in Saskatchewan were obtained from schools at Laird, Lipton, and near Regina, where they occurred in large numbers. Infestations occurred also in two dwellings at Ottawa, Ont, Proc. ent. Soc. Ont. 90 (1959)—1960 72 MILLIPEDES.—Near Buckingham, Que., millipedes invaded buildings in outbreak num- bers, the second major outbreak in this areas in recent years. Millipedes occurred in normal numbers in many basements and dwellings in the Ottawa Valley, and were reported as pests in southern British Columbia, Alberta, and Quebec. MITES.—The clover mite invaded dwellings in the Kamloops and Okanagan, B.C., areas, and in several localities in Alberta, Saskatchewan, Ontario, and Quebec. It was abundant in St. John’s, Nfld. In Saskatoon, Sask., and Ottawa, Ont., the chicken mite invaded a few dwellings, one infestation near Ottawa being severe enough to temporarily drive out the occupants. ROOT WEEVILS.—Hibernating adults of the strawberry root weevil commonly invaded dwellings in most provinces. In a few instances in Ontario, small numbers of the black vine weevil were also present. Another species that invaded a dwelling near Ottawa was identified as Brachyrhinus rugostriatus (Goeze). SILVERFISH.—As usual, silverfish occurred commonly from coast to coast, especially in apartment buildings. TERMITES.—In Vancouver, B.C., Zootermopsis angusticollis (Hagen) severely infested several houses. In Medicine Hat, Alta., Reticulitermes sp., prob. tibialis Banks, severely dam- aged wood in the lower structure of two houses. In Toronto, R. flavipes (Koll.) continued to spread and cause extensive damage. WOOD BORERS.—In Ottawa, Ont., infestations of the wharf borer occurred in two houses and a laboratory building. Specimens were received also from Quebec City, Que., and Willowdale, Ont. Large numbers of a bark beetle, Leperisinus aculeatus (Say) emerged from wocd stored in a basement in Ottawa. Phymatodes dimidiatus (Kby.) and Callidium subo- pacum Sw. emerged from the logs of a cabin near Kamloops, B.C. Power-post beetles were frequently reported causing damage in buildings in southwestern Ontario and Prince Edward Island. STORED PRODUCT INSECTS STORED GRAIN INSECTS.—In grain elevators at Vancouver, B.C., the moths Hofman- nophila pseudospretella (Staint.) and Endrosis sarcitrella (L.) continued to be the most commonly encountered pests. Other insects occurring in smaller number included the granary weevil, the yellow mealworm, the spider beetle Ptinus ocellus Brown, the tobacco moth, and Pseudeurostus hilleri (Reit.). Psocids an dmites were also present. In addition to the major pests, the black carpet beetle was found in small numbers in elevators at Creston and Wynndel. No serious outbreaks occurred, but in one elevator the granary weevil was difficult to control. In the Prairie Provinces, reports of the rusty grain beetle were at the lowest ebb in nine years, probably a result of a decrease in farm-stored grain. Most infestations occurred in wheat stored on farms and in commercial flat storages. The meal moth, the rusty erain beetle, Anthicus floralis (L.), the saw-toothed grain beetle, the grain mite, and the mites Haemolaelaps casalis (Berlese) (=H. megaventralis (Ewing)) and H. glasgowi (Ewing) were the more numerous pests. A moderate infestation of the mite Tydeus interruptus Thor in 25,000 bushels of oats at Poplar Point, Man., was probably the first record of this mite in Canada. In southwestern Ontario, several severe infestations of the meal moth occurred in stored seed corn, MILL AND WAREHOUSE INSECTS.—In coastal cities of British Columbia, the spider beetle Ptinus ocellus Brown was the most common pest in mills and warehouses, and in the imterior of the. Province the black carpet beetle was the major pest in such storages. Other pests in diminishing order of recorded cccurrence in the Province were the brown house moth, the Mediterranean flour moth, the yellow mealworm, the larder beetle, the confused flour beetle, the granary weevil, the Indian-meal moth, the varied carpet beetle (coastal Cities), the drug-store beetle, the cadelle, the white-marked spider beetle, the white-shouldered house moth, the broad-horned flour beetle, and a few others. Three mite species occurred in outbreak numbers in a seed plant at Ladner, severely damaging sugar-beet seed. In the Prairie Provinces the confused flour beetle occurred commonly in flour mills, the saw- tocthed grain beetle in one flour mill, and the red flour beetle in crushed grain. In Peterborough, Ont., the almond moth, Xenephestia cautella (Wlkr.), infested bird seed in a pet shop. FOOD-INFESTING INSECTS.—By far the most troublesome pest in stores and dwellings Was the saw-toothed grain beetle. Other frequently reported pests of general distribution included the drug-store beetle, the confused flour beetle, and the Indian-meal moth. The cigarette beetle was fairly numerous in stores and dwellings in southern Quebec. Mealworms occurred fairly commonly in Alberta, and the yellow mealworm infested dry beans in New Brunswick. The red flour beetle was fairly numerous in Alberta and Saskatchewan, and the Tusty grain beetle, rice weevil, and spider beetles in British Columbia and Alberta. Proc. ent. Soc. Ont. 90 (1959)—1960 7 Ne ed a a rays he. PROCEEDINGS OF THE NINETY-SIXTH ANNUAL MEETING ENTOMOLOGICAL SOCIETY OF ONTARIO November 30 — December 3, 1959 A joint meeting of the Entomological Societies of Ontario, Canada and America was held in the Sheraton-Cadillac Hotel, Detroit, "Michigan, U.S.A. on 30 November, Ist, 2nd and 3rd of December, 1959. This marked the 96th Annual Meeting of the Entomological Society of Ontario, the 9th Annual Meeting of the Entomological Society of Canada and the 7th Annual Meeting of the Entomological Society of America. The meeting was opened at 9:00 a.m. Monday, 30 November, 1959 in the Grand Ballroom of the Sheraton-Cadillac Hotel, Detroit by the Presidents of the three Societies. Lewis C. Miriani, Mayor of Detroit, and. Michael J. Patrick, Mayor of Windsor welcomed the delegates. ‘The meeting then proceeded as per programme. The Annual Business Meeting of the Entomological Society of Ontario was held at 1:30 p-m. in the Normandie Room, Sheraton-Cadillac Hotel, Detroit, on 30th November, 1959, A total of 30 members attended. Minutes of Last Meeting— As these were published, a motion by S. E. Dixon and L. A. Roadhouse that they be adopted was approved. Mail Ballot— The President then announced the results of the mail ballot which was conducted during 1959 showing the Board of Directors for 1960 to be: Joan F. Bronskill A. M. Heimpel D. M. Davies J. F. McAlpine W. H. Foott D. G. Peterson H. B. Wressell It was moved and seconded by M. L. Prebble and C. Copeland that these results be accepted—carried. Nomination Committee— The President then requested permission to name such a committee which would be required to set up a proposed slate of officers and submit this list to the Secretary so that a mail ballot could be drawn up and circulated to the members. Permission was granted. Auditors It was moved and seconded by H. W. Goble and J. F. McAlpine that the Society return the same auditors in 1960 as had been active in 1959. Carried. Report on Activities— The President reported that the present Board had cleared up the problems surrounding the printing of the Annual Report, and had incorporated a definite status for this publication in the revised constitution. Constitution Revision— The proposed revision and changes in the revision had been circulated to all members for comment and it was proposed by D. M. Davies and seconded by B. M. McGugan that the additions as listed be adopted. Carried. Financial Statement— The Financial Statement for the past year was presented by the Secretary-Treasurer and it was moved by L. L. Reed and L. A. Miller that the Statement be approved. Carried. Meetings— It was brought to the attention of the meeting that it was becoming increasingly difficult for members to obtain permission to travel in order to attend Committee and Board meetings as active members of such groups within the Society. J. MacB. Cameron asked if it were possible for the Society to work out some method whereby the cost of such travel could be borne partly by the Society. He felt that if this were not feasible, then there was little value in having members on these Committees and Boards who lived more than a few miles apart. Proc, ent. Soc. Ont. 90 (1959)—1960 ah The President replied that this had been considered but it had been decided that the Society did not have the necessary funds to finance such a scheme. A. W. Baker inquired if this policy was in effect within all professional groups in the Civil Service and if this were so, then he felt that members would not be able to carry out their duties. Further discussion, during which other members, including D. G. Peterson, took part, brought out the point that this situation was not all clear owing to the fact that there did not appear to be any definite policy as to which account such travelling could be charged. | It was decided that this matter be inquired into and an attempt made to clarify the situation. It was proposed by S. E. Dixon and Joan F. Bronskill that this matter be referred to the incoming Board. Carried. New President— The President then announced and introduced the new President for 1960, D. G. Peterson. Appreciation— The President expressed his thanks to all Committee and Board members for their loyalty and work during his period of office. A. W. Baker expressed the appreciation of all members of the Society to the outgoing President and Board members for a job well done. This met with the whole-hearted approval of all present. The meeting then adjourned. ENTOMOLOGICAL SOCIETY OF ONTARIO Guelph, Ontario, Canada FINANCIAL STATEMENT 1958 - 1959 RECEIPTS EXPENDITURES 10a B NG (eee eran wenn Aen. ol G Glnciy R aca ney $1,537.00 1: Dues. to: Gan. Ent, Soce sa e7es $1,154.00 22 Back, .NUMIDELS, inane ee 4.60 2.) Grant to Can. Entxo ieee 125.00 De Reprise 2 o:a04 cnn. einen nae. oe 261.00 3.2 Exchange <0 c0i1) ot eee alls) AE SALINDCLESE eae este CE Nae Saeen cet arden 18.00 4. Honorarium (Library) ................ 100.00 Ob GMAlItS, > ysnyy. (ek geee eae eee an ke 300.00 5 Rubber ‘stamp: (2) 2 22 5.85 62 Postavre (22..2o 65.00 7, Reprints’ 2.504403 eee 148.40 8: Programmes =. 2.06 eee 13.50 9. Envelopes and Printing ............... 89.60 10s "EX Press <2. se bbb Pi. Auditors: i058 2 25 5.00 1223 Chee ito. Member /.2:) eee 8.00 $2,120.60 $1,723.09 Bank Balance 20 October 1958.......... $ 413.68 Bank Balance 31 October 1959......... $ 811.19 $2,534.28 $2,534.28 Bonds’: 20 ‘October: 1958x265. 3. oe $ 400.00 Bonds 31 October 1959...........0..c4.5.. $ 400.00 Auditors: W. C. Allan, C. J. Payton Secretary-Treasurer, B. D. Clarkson Proc. ent. Soc. Ont. 90 (1959)—1960 31 October 1959. PUBLICATION POLICY AND MANUSCRIPT RULES FOR THE PROCEEDINGS In 1869, the Board of the Agricultural and Arts Association voted Four Hundred Dollars to the Entomological Society of Canada on condition that the Society publish a report on noxious insects. The report was published in 1871. As a result of the excellence of the report, the Government of Ontario gave the Society an annual grant, and in accordance with this action, the Society was incorporated in 1871 as the Entomological Society of Ontario. The Society is obligated to submit to the Minister of Agriculture for Ontario an annual report of its proceedings and “such general information on matters of special interest to the Society as the Society has been able to obtain”. Information on matters of special interest to the Society is presented in the Proceedings _ as invitation and submitted papers, symposia, scientific notes and reviews. These are written by members of the Society as well as by other entomologists. Many of the papers are submitted after presentation to the annual meeting of the Society but this is not a prerequisite for acceptance. In 1958, during the preparation of Volume 88 of the Report, the Society’s Publication Committee acted as an editorial board to advise the Editor. This practice was continued, and the appointment of an Editorial Board was authorized in the revised Constitution and By-laws that were approved at the annual meeting in December, 1959. A paper submitted for inclusion in the Proceedings should not have been, or should not subsequently be published elsewhere. The criteria for acceptance of a paper are the merit of its content and the clarity and conciseness of its presentation. Papers are accepted only if conclusions are sound, based on reliable experimental methods and adequate data. In accord- ance with this policy, the Editor, acting with the advice of the Editorial Board, may submit a Manuscript to one or more reviewers. This may not be necessary if a manuscript is accompanied by the written approval of a recognized person or persons familiar with the subject. When a paper is unacceptable, it is returned to the author with an explanation. Authors are given an opportunity to accept, modify or rebut a reviewers comments. If revisions are made, all pages of the original manuscript, as well as retyped pages, must be returned to the Editor. The date off acceptance for publication is that date on which the manuscript is accepted in final form. Preparation of Manuscripts Two copies of a manuscript are required by the Editor. For the ribbon copy, use paper 8¥% x 11 inches in size, of medium weight and good quality. Flimsy, non-glossy paper may be used for the carbon copy. Type on only one side of the paper, making all four margins at least 1Y inches wide. Double space all typed material, including text, footnotes, tables, captions and references. Number all pages, including those for tables and captions for illustrations. Use paper clips, not staples or pins to fasten the manuscript. Mail the manuscript flat, not folded or rolled. Give the title of the paper, the by-line, and footnotes thereto on a separate page at the beginning of the manuscript. Omit the author’s professional status, but give the official address of the author as a footnote to the by-line, unless already stated in a footnote to the title. ; A summary is required for all but very short papers. The summary should be informative, Stating the main findings and the details of methods that are critical in evaluating the findings. Type footnotes immediately below the reference to them in the text or elswhere, not at the bottom of the page. Indent the first line of a footnote as for a paragraph and draw a line above and below the footnote. Number footnotes on the title page and in the text consecutively throughout the paper. Use letters for footnotes to tables. Use capitals for headings that are to be in full capitals. Use capitals and lower case, if the heading is to be in large and small capitals, or capitals and lower case. Underline all side headings, and, in other headings, only those words that are to be in italics. Give citations to references in the text, e.g., “(4)”, and place the references in a list at the end of the text. Arrange them alphabetically by the author’s last name, followed by the author’s initials, year (in parenthesis), title, name of publication (abbreviated as in the World List of Scientific Publications), volume number, and page numbers, e.g., (14) Dor, J. and Dor, M. (1888). Some observations on cockroaches (Orthoptera: Blattidae). Proc. ent. Soc. Ont. 5: 46-49. List books by author, date, title, edition, published, and place of publication. Type each table on a separate sheet and place them at the end of the text. Show where the table is desired in the text by writing “Table I near here” encircled by a line. Reduce tables to the simplest form and do not use them if th text or an illustration give the same Proc. ent. Soc. Ont. 90 (1959)—1960 79 informations. Make tables complete without reference to the text. Use a double horizontal line immediately below the title of the table, and single horizontal lines below the column headings and at the bottom of the table. Avoid the use of vertical or other horizontal lines. I Use illustrations only to present material that is not included in tables, or that is not shown more readily in tables or summarized in the text. Drawings shouid be on pure white or light blue cross-hatched paper. Include a photographic copy of each illustration for trans- mittal to reviewers. On the back of each illustration, place the name of the author, the title of the paper, and the figure number. Type the captions for illustrations on a separate page cr pages, and place this at the end of the manuscript. Show where the figure is desired in the text by writing “Figure I near here” encircled by a line. Supply all organisms with scientific names and authority, and, if approved, the common names. Give the common names of chemicals, if approved. Chemical names, as given in Chemical Abstracts, should be stated in parenthesis when the chemicals are first referred to in the text, or preferably in footnotes to tables. Capitalize brand names and, except for universally known materials such as DDT, give the names and addresses of the manufacturers in the text or as footnotes to tables. ; Galley Proofs Proofs will be sent to the authors to read and correct before publication. Limit alterations to the correction of typographical or factual errors. Return the corrected proof promptly to the Editor, by return mail if possible. Abstracts Authors will be requested, when returning corrected galley proofs, to prepare an abstract of their papers for Biological Abstracts. A form will be provided for this purpose. Reprints When submitting a manuscript to the Editor, indicate the number of reprints that will be required. Authors will be informed of the approximate cost of the reprints, and should place an order not later than when returning the galley proofs. PUBLICATIONS COMMITTEE D. G. Peterson (Chairman) D. M. Davies G. F. Manson Proc. ent. Soc. Ont. 90 (1959)—1960 eM Po PO er ey ee Oe eer eve” even as 80 1a.) Ld seal % : is be ks ig INDEX Section III is not included in this Index. A PAOMGOLUS IVYSETOX 0.052 Oe: Zon 2128 BM TU EI EDUEE A. 8. Nese tedapins cebu cberse cats 53 CANTILLON 53 SLL EULA OTIS aie Se pipe ieeet ARI aise ren ne ea se 23, 26 UiNIOVOIE 2a aT on tent en On aE ete rips aS AD PMemoNOI TWLOSAIC 2...) 2...) heist cceebeeneeetiese Zi) PMO VEDCMS 5.0. ay htsndiceeeesesconees Dies MMM CAHUCTOUUAT jai. cle! allie ert 15 Perera ee ee Ra dies 39 PMI STO RULINICLLG: oie. chs cesses tcauetesendnssnes 15 PSO SCTLALOUUG 8. 2 Le eens cscch tno 19 ANTE OOS 4 CCRT OTN ee ena Cee ee 34 LICL) C2) Oe aie AN eee ee ner Sat A DIIIICIS o> 2 AOS I a ne ea an ere ee ae De BE MeMNEINOWS VITUS cr 2.) oc. cales ass dusecsunees Cl B OAC TIMID: OCICS NEMO RE RR oe ee 14, 15 WMI RNS ere Fe ee as eh eke des liebe 14 POS IUOKE. ye OS ie al es mE ER re Re 14, 15 MUURRITROVENUSYS 62380). i 0. ho es tee cane 15,7 16; 18 Perabemolooical COmtrol sii... ase eee 13 er MMMmOMminOZOl A ee 31, 32 OOOO By ee Ble BPawere HOMBVOUMLUDD oe es, 31, 32; °33 I CUCU, TCHR Pee ae ee ee B07 3325033 CONDOS oe a AA a a BAI 208: “C2 GWOICERD TE: es GI Baas an Po 30, 32, 34 Lido TDW po ie iene ee a ae eee 34 IES) Spcje dig Sis cae ena gt ee epee 34 TALES <0, CaS a gg en MR ae 30 US ELE, TONIC os a a er ed eles 34 Rr Ye Ne) Se OL a, 22 eMC AD ANESG yo viele 14, 38 Mae VCORCIINCLLIG 2 a 22 BMD, oe i eles 53 Buekencurnamt Call: mites... csc. 22 TP ONINETA OID oe. ee eee crasseatas ike. 15 PIGUESOUNIVE DV ASSUCOE | o.)e.000 sc. seeks cans 54 | S10 VTi TCT IVa 00 a VAR eae ny er a er 37 UL TIP ag ea aie 34 C +. 1 VIS Vee FO) AWG Ee See te an One et a 54 Mempocapsa pomonella 0... has ioe 14 Marcwoilar alfalfa: 0. Se de 15 POIMGLOSGYIUMUS “SP... eke a 34 PERO GNIS SU MII oo Nae a ek Be 38 gran OSCUIUS. 0. ce ak) NO 34 Mreemreliid Weetles 2). oul eich. 22 MeecovaGiilis aGcridorium: |i. cies MS cia, 1 Re TT O UN Desay, Cee Oe eee 14 Pomunel bacteriological: (o.. 0 22... a. 13 Poamporer Huropean 6.0.6 38, 139 Beratnben eChles ie. iu ee 39 PmeiMieeVetsiON! (2 ).) 1 weak oss Day 28: 1 ST ELITIST DEES aa ee ee cane 23 Ee MM COUDESENIS 82) 18.0 i ale oes acted Zi 83 D Der niae CM LOR AWG CHSOME oe Fis tikes ene ee 34 Diabrotica undecimpunctata 20.0... 53 Dutehi elimipdiscase set, Ve ke twee ae ce has 38 E EE PUSONAVOP US APLESUUS Monee oa. ce Siete see! 10 PEGVOMNY CSUMUNSUAUOSUS tine ao% re he acme 23; 26 ELIS Eh Ren Maer eerie ee noni Wi Meee NO bE 27 EO biyida cme earn ts eats tomate, yvonne 22 WOT ACR QELS MACDUWS s fis g one fae eat 34 BULOpeai Comm DONeT a5.2s8 eben 38, 39 E ioe adie aU Pea RRR eer ay te ts a ee ee 26 TOS AC Sh a ee oa ce kl eM end ae 23520 Eskeale selina th, ca einen Ween -b areek en Neue he Boe Ep 34 lies Waite ies een nae tea ie he ie ee 30 J SUIGNUN eae sa0YO) 0) a) ane eas ha cA. Pela tie ce aie ne AON ra 15 G Grapnolgng, MOVSEO werk. «ik ye eee 38 GADHGBUICON Whe sen sai tara tat gid an Meni meets Suk tc ann 54 Gy PSvermMOthi meme some tae Meat VM ynaien 38 H I alos Dan nrencante wieteeccwea Secular eae Me eee fous yi EVOMOLTU GDC MUSIC eel? Vesta ene Res 53 TAS DONOR DOSTICG, oa? A Ue ge eae ENR CPR cin tee 39 I GHOTOTN SSUSANS Dinero me ON Csr) Len ke sae 34 MiallbanesGVeOT Assn hate. ter tates Cn tere eae 27 J amaMnese beetle. iia: es ayy eet, acces 145.38 L Te agen: Swill ese ae teat BO MD ek cde Pactra 15 Weathoppenn SispOCheda tee: sna. ee 7 Weecithiinase iG) Steet oe ae or eis ery 1 DE OMA IIE HTD DULL LONGLUTID ee eee oe aes te ene Noe 27 | ARO ONG NOAM SRR a ea Reg TS ae et Baa LI 27 Mometcaned: Myotis! AG eee crs ee ee 34 M IWIGGROSECIES fASGL) NOMS. (5 ie 3 Cun aa en 7 Malla COI ir Vcte ee AM eae MC 54 Miethiylie bromide si: Whi ate cst ee eee 39 MTCHOSpOTiGHae es ache eas ee ee ae 53 Mites blackcurrant, toalline ae ey ee? PO BAe dee oe aR eRe Nee he cede eA ea Ge yu 26 SPCLEMOMIG. WAM cine Muni on octet 53 Mosaic, SaorOpyrone (ia, ken nemnuec omieme a nee 2 HUG SAEs ie ACNE 2 Ace area eae 23,26 DEAGD eine: ae ce sNee Eee Rune oe 23% 26 VECO ASS tar ec oa LE ea ear Se Za 2 |: WIC ACSDOUN Fry eh tuk das her ree een PAB ys PAS) WANEAT CS Enel kon eres 8 ee Nor ghee 23, 24 MOE a bro wiletallis yi6 1s kh te aes i 37 GLOYGHITN ASL A Ue Meee tate 4 phaer mite inate e fin rR: 14 IH OLU D4 Ua ale cake Se Mechel Man eu MART Os Gk Ree gt 15 CORA OFS i a RO SU ane a gh AACS 2 S22 38 OMleNitalechCule ot eae oa ees Ta ae, mone 38 MEV ODO PSIG (CENUbIS “ci oes i genes 34 NEN OLS NM CWOLUS Seccns chek cle ay ety Loken ty eae 34 Miyous lone -cared seni aaa fo cae 34 IMI OEIS# SV UNA A ee oe ee Re te ema 34 DVN OULS IITA TUCNSIS: Fee We cathe ree eo a see 34 N ING@R26 26 Ore LEAS Late cae On epee te wman 54 IN O'SCTIUOIES Pertti Sheek Phe ne eM eR CEA 53 INV CteMib MGA er Oo cn, St oe Re Ca tea 30 NN OMIA PRACOTEROCE «+. o 0) line, ea ae aul O Oniental truth: moti cases cn eee 34 OF nt ROGOTUS SPu aio) ba taa cnet Mee aes 34 P PTAs naar ee ee ed eis eee eee ce 34 REACH SMNOSAIG sacs owas eet csek Cerne 23526 Real sy Ula loch ee nee Cad ee sae 3B) Bepeniial nyesrass: oi ig ei ee ee eee ie 27 OSCE teen Stee on at ces Ak ae a anaes 54 EN) GO DIAUS MOUS Gin ene ct aie Oy Oe ae 23, 24 POPU GTA POMUCd= | A Sete oa ee 14, 38 PORBMCLIG ACUSPON Os Sire CeR ae sliaaie Went eae 38 EAUSEUD IDOE O MERUCH SOULE Hi vee a eet aN A ae ee 15 84 Pseudomonas aeruginosa PsyNay pear: sh. 7 a eee 39 ENT OUST -NUOTIOMS i... ne 38, 39 R RIDES WHGNUM 2 Se ea 24 Riyectdss,, Malian) 20 a5. ee eee 27 perennial Vo os0.6 0 ese 27 Ryesrass Mosaic, iho 2 eal S Sawily;* larch), c200.0 102k eee ee lay) SChIStOCETGG: SPP hui ee 14 SchraGdawn: 3.3). yecivccsc 54 Si wow he eae sc ae iD) Semulium venustum oe ee 53 OU EOUUWIN: WN Es ce ee 53 Sixspotted leafhopper %...2 5. tae vi Sperchon Spo 525... is eee eee DE Sperchonid® mite) 4)... a ee eee 53 SVSCOK) 58) oon cyan ee ee eee 54 Vv Vasates mcokenuel 2... ee ee 28 Virus; asropyron MlOSsalG 2 ee ai aster-yellows \ 0.2. tease eee a wheat: streak: mosaic 4). yee es 22 W Weevil, \alfaliay i 005 39 Wheat spot mosaic <3). eee 235.25 streak mosaic =o. Se eee 23, 24 ¥ Yuma: «Myotis: iisyoo 2 aa on oe AUTHORS’ GUIDE ~~ TT; Wn lence concerning, and orders for reprints should be addressed to the Secretary- mological Society of Ontario, Ontario Agricultural College, Guelph, Ontario. a ae me mMinesc ms og PROCEELANGS NTI OMOLOGICAL Volume Ninety-One SOCIETY 1960 (Published September, 1961) . PUBLISHED BY AUTHORITY, QF apt, ‘#exed HE HONOURABLE WILLIAM A, GOODFELLOW, MINISTER OF AGRICULTURE FOR ONTARIO PROCLELHNGS of He ENTOMOLOGICAL SOCLETY OF ONTARIO Volume Ninety-One 1960 Published September, 1961 by authority of THE HONOURABLE WILLIAM A. GOODFELLOW Minister of Agriculture for Ontario EDITOR D. G. PETERSON, P.O. Box 248, Guelph, Ontario EDITORIAL BOARD D. M. DAVIES, Department of Biology, McMaster University, Hamilton W. G. FRIEND, Department of Zoology, University of Toronto, Toronto G. F. MANSON, Research Branch, Canada Department of Agriculture, Chatham D. G. PETERSON, Research Branch, Canada Department of Agriculture, Guelph ENTOMOLOGICAL SOCIETY OF ONTARIO OFFICERS 1959 - 1960 President: D. G. PETERSON, Guelph Vice-President: D. M. DAviES, Hamilton Directors: . . JOAN F. BRONSKILL, Belleville W. H. Foott, Harrow A. M. HEIMPEL, Sault Ste. Marie J. F. MCALPINE, Ottawa H. B. WRESSELL, Chatham Secretary-Treasurer: W. C. ALLAN, Guelph Correspondence about membership in the Society, or exchange of publications should be addressed to the Secretary-Treasurer, Dr. C. C. Steward, P.O. Box 248, Guelph, Ontario. : CONTENTS Volume 91 I. SYMPOSIA Insect Pathology EEOC ETON ein epee ee NONE ae Ve AUN AMEN! yuan ng hs CU a atk nD A. J. MUSGRAVE Some effects of microbial pathogens on insects .......0.........ccccceeeeeeeeee T. A. ANGUS Insect diseases resulting from malnutrition ......00....0000.. H, Li. House Microbial infections of the honeybee and their control ........ H. KATZNELSON Pathological conditions in insects resulting from chemical LIMO MONG SCA TIN UNV eR iin hyo cotoiins dows sis eae ee abe E. H. SALKELD The Effect of Chemical Control of Insects on Wildlife Conservation BETO CUUTC LOM ce cou hoe AT a ON rs Lee AN LONE a 0D en Nd C. C. STEWARD Insecticide applications and their effect on wildlife .................... ADEN OS The effect of chemical control of insects on beekeeping ............ M. V. SMITH EEOressional FeSpONSIONIty eect Oke een Pare eS ota. H. HurRTIG Effects of forest spraying with DDT on aquatic insects, food of STIMoOn aAnG= thoOul,n In NeW » Db rUMSWIeCk 820i ee i es Ke Ps Ips Evaluation of the present in the light of past experience ... A. W. A. BROWN II. SUBMITTED PAPERS Control of caterpillars on late cabbage in central Ontario and SESUCKMN GO UEDEC st LOD Sato On akin ek ena el een ta nae fo) L. M. Cass The application of pH determinations to insect pathology ........ A. M. HEIMPEL The Tabanidae (Diptera) Of Ontario 2.22500: L. L. PECHUMAN, H. J. TESKEY and D. M. DAVIES The mosquitoes of Ontario (Diptera:Culicidae) with keys to the species and notes on distribution ........ C. C. STEWARD and J. W. MCWADE Thymelicus lineola (Ochs.) (Lepidoptera: Hesperiidae) a pest of hay and pasture grasses in southern Ontario 2...0100..0002000. D. H. PENGELLY . Field experiment on the use of a nematode for the control 4 of vegetable crop insects .................0000000... H. E. WELCH and L. J. BRIAND Wt. REVIEWS Present status of the sawfly family Diprionidae Chivmenopteray) ani Ontallog 36 3) ee Oe po ee, C. E. ATwoop The oriental fruit moth, Grapholitha molesta (Busck) , (Lepidoptera:Olethreutidae) in Ontario «0.000000 G. G. DUSTAN * Cattle grubs (Diptera:Hypodermatidae) in Ontario .................... H. J. TESKEY The history and development of the European corn borer, Ostrinia nubilalis (Hbn.) (Lepidoptera:Pyraustidae) as an Economic tpesemim OnlanionKrs eso We Me ale H. B. WRESSELL Summary of important insect infestations, occurrences and damage in agricultural areas of Canada in 1960 ................ C. G. MACNAyY IV. NOTES Colour affects the landing of bloodsucking black flies (Diptera:Simuliidae) on their hosts .........0000.00 D. M. DAVIES An infestation of Comstock mealybug, Pseudococcus comstocki (Kuw.) (Homoptera:Coccoidea) on peach in Ontario .................... J. H. H. PHILLIPS Results of rearing some coccinellid (Coleoptera :Coccinellidae) LAGVAC OMUVEIOTOUS OMENS oy ter pee rl Use Naa Me B. C. SMITH Wom GMsMAMeS OLMIMSCCUS ek Ruy e: Ceclrce lo een dscok even Liles. C. G. MacNay VY. THE SOCIETY nocecdines or the 97th, annual meetine ec iahl uie dees ce.s eters bovend ie dodsonstedean Re ATIGI NS LALEIMCIL ge Utah eka aii yaa mii des a ee Umar ens aa Mee Reports SCompiuttec on, common names of 1nSects 4.08 sige isis ole ease embee side eeten eed eee EAT, COMMMILCCe Me erect ered ie a ao Nis Ae ot RS haa ee 27 a EMU DIN AUIOMS PEOHIUMIL LOC ai Me ys coe te BON Ma Mes CR! Fee Barf ale a ae a ea ila Notices ‘Taney STEM TESTI (24 9) EASY 09 Ae ek ies Pataca eR ie Secs gan INGOT OMe Oba RCILOWSi. eee st tint acne, es AUR corn th Nib 1s ee A ayy Obituaries De ABs JB oir e(o Ley d USSG Fe US C51 8 se cas te a ern eS ae ee a pera a Be EU AO INVC ie LON Ae ROG One inic aussie LN IM UNDA CEE My Ae cl lek) ai eg Ve mMOMmMsOMen NO ZO21 OOO)! Mie a eh ala MT cs ek NESS 0s a Mee eae WHE Sy an gens) Gir MN DISH Bagel) Oia SOV G2, Je Mie I A aU. NE EH ata MRI Lk RU NCO RU RU a (Eo UIT ID WERT Ts Asie A OU TOn A MeO ae tle TS UR Ae A Ue aR oa, RR Wis! an me) = ee we a Oo) a es INSECT PATHOLOGY’ INTRODUCTION A. J. MUSGRAVE’ E. A. Steinhaus, to whom all entomologists owe a debt of gratitude for his authorship of “Principles of Insect Pathology”, the only textbook of its kind, has made it clear that insect pathology is a distinct discipline of broad scope dealing with symptoms, causes and morbid consequences of disease in insects. Though diseases of insects began to receive serious study in the middle of the last century, when it became clear that certain diseases of silkworms were of microbial origin, it was, undoubtedly, Stein- haus who was responsible for launching insect pathology as a discipline in its own right. The subject includes investigations on the histological, physiological, biochemical and pharmacological effects on insects of toxic materials and of parasitic viruses, bacteria, protozoa, nematodes and fungi; and in- corporates studies of diseases due to faulty nutrition and of the part played in insect metabolism by beneficial symbictes. As an academic discipline, then, insect pathology offers abundant scope for scholarly investigations. At the present time, however, the subject is of particular significance. Chemical control of insects has, for many years, been a necessary adjunct of agricultural, sanitary and medical progress, but the phenomenon of insect resistance to insecticides and the apparent commercial possibilities of certain new synthetic compounds have led to the introduction of an increas- ing number of new pesticides. The classic methods of biological control by the introduction of parasites, and the new ‘“‘genetical’’ method of control by release of sterile males, while successful in certain areas, are of limited application; and insect control by microbial agents and nematodes is still in early stages of development. Moreover, in the minds of some it seems that there are dangers inherent in the disturbance caused to the “balance of nature’ by the use of chemical compounds. But the “balance of nature’, if it is a valid concept, is not static and constantly needs re- assessing. Moreover, man upsets it wherever he goes with his civilization; and it is hard to see how such practices as the introduction of parasites and the artificial preservation of game animals do not also upset the “balance of nature.” It is clear, then, that whatever we do in controlling or eradicating animal populations, we should know what we are doing—at least to the maximum possible extent in conformity with available knowledge. Ideally then, a knowledge of the causes of pathological conditions in animals we wish to exterminate or preserve, is a prerequisite to a rational procedure. Thus no apology is needed for offering a symposium on insect patho- logy at this time. The papers presented here cover a good deal, but not all, of the broad spectrum of insect pathology. One of the animals with which man has for years been upsetting the “balance of nature” is the honey bee. Even in this synthetic age the honey bee is of sufficient importance for its diseases to be of concern. So the ‘Symposium opens with a paper on the symptomatology of the microbial diseases of the honey bee by H. Katznelson. A paper by H. L. House deals 1A symposium presented at the 97th annual meeting of the Entomological Society of Ontario, Guelph, Ontario, November 24-24, 1960. 2Department of Zoology, Ontario Agricultural College, Guelph, Ontario. Proc. ent. Soc. Ont. 91 (1960) 1961 7 with the diseases resulting from malnutrition and is thus of interest to those who rear insects in the laboratory as well as to those who try to exterminate them; E. H. Salkeld discusses pathological and biochemical conditions in insects caused by pesticides; and T. A. Angus reviews the vast area of microbial disease agents and the resultant pathological con- ditions. In reading the different papers in the symposium one is impressed by both the extent of our knowledge and the depth of our ignorance. Do we really know how any toxic agent actually achieves its effect or do we hide our ignorance, even from ourselves, by such terms as “detoxifying mechanisms”, “competitive inhibition’ or “phase distribution relation- ships’? How many of the micro-organisms pathogenic to insects do we know of? And the normal flora and fauna of insects? And while significant contributions have been made to our knowledge of insect nutrition, par- ticularly by Canadians, Dr. House himself remarks in his paper that “‘until more work is done on the nutritional diseases of insects there is little scope for significant generalizations’. This, then, is the depth of our ignorance. The extent of our knowledge is adequately revealed in the papers of the symposium; and a fascinating story it is. It is surely reasonable to suggest, moreover, that other branches of knowledge will benefit from advances made, and to be made, in insect pathology; to cite a few examples: the effects of nutrition on tumour occurrence in Drosophila, the nature and effect of the toxic crystals in pathogenic bacteria and the pharmacody- namics of pesticide chemicals in insects are all phenomena that could easily have implications for human pathology and medicine. Salkeld doubts if the abnormal can be recognized if the normal is not known. Logical and idealistic as this objective is, it seems doubtful if we can persuade mankind to wait until we have achieved it. But it is an ideal worth working for. SOME EFFECTS OF MICROBIAL PATHOGENS ON INSECTS’ T, A. ANGUS Steinhaus has referred to insect pathology as observations concerning the cause, symptomatology, and epizootiology of the diseases of insects, and the study of the structural, chemical and functional alternations in the body of the insect resulting from disease or injury. My intention is to discuss briefly in general terms injuries observed in insects suffering from microbial infections. Insects are infected and affected by viruses, bacteria, fungi, protozoa and rickettsiae. The last mentioned, are the least well known, and only a few studies have been made of the tissue changes associated with such diseases. The best known are the fatal “blue” disease of Japanese beetle larvae (Popillia japonica New.) which also affects some other species, and a somewhat similar condition in the larvae of Melolontha vulgaris. Infected Japanese beetle larvae show a greenish-blue discolouration of the fat 1Contribution No. 26, Insect Pathology Research Institute, Research Branch, Canada Department of Agriculture, Sault Ste. Marie, Ontario, Canada; presented as part of a symposium on insect pathology to the 97th annual meeting of the Entomological ‘Society of Ontario, Guelph, Ontario, November 23-24, 1960. Proc. ent. Soc. Ont. 91 (1960) 1961 8 body about three weeks after innoculation but remain normally active for more than a month after this. Shortly before death the larvae become sluggish, cease feeding and the blood becomes cloudy. This is due to the presence in the serum of numerous small particles (presumably the rickettsial bodies) which are also found in the nuclei of infected cells. The same kind of symptoms are seen in infected Melolontha larvae except that the inclusions seem to originate in the cytoplasm of fat and blood cells. This is reminiscent of virus infections except that the rickettsial diseases take from eight to sixteen weeks to run their course. In virus diseases of insects where death may occur in a few days or a week or two at the most, the incubation time varies with dosage, con- dition of the host, temperature, and so on. The best known virus diseases are the polyhedroses, characterized by the presence of polyhedral-shaped inclusion bodies. A very large number of Lepidoptera are attacked by nuclear polyhedroses and infected larvae usually show few external symp- toms until late in the disease. Moribund larvae may be limp, slightly swollen, and frequently change to a paler colour probably due to the presence of large numbers of inclusion bodies in the blood serum. At this stage the larval integument becomes very fragile and if broken a char- acteristic milky white fluid emerges. The fluid contains enormous numbers of the polyhedral-shaped inclusion bodies; these originate in the nuclei of most organs and blood cells. In Bombyx mori L. about 4-5 days after infection, small granules (which appear to grow in a ring around a dense central mass) can be seen in the nuclei. The infected nuclei increase greatly in size and then poly- hedra becomes visible. The polyhedra increase in size and number until the nucleus is completely filled with the inclusion bodies. Finally, the nuclear and cell membranes rupture to release the polyhedra. An increasing number of cells become involved, the integrity of tissues and organs is destroyed. A number of sawfly species are attacked by nuclear poly- hedroses and these have been intensively studied by Bird. In this group the polyhedra are formed only in the nuclei of the digestive cells of the mid-gut epilthelium. In addition to the nuclear polyhedroses, there are a number of diseases known in which the polyhedron develops not in the cell nucleus but in the cytoplasm. The granuloses comprise another group of cytoplasmic virus diseases of insects in which the inclusion body is small, and ellipsoidal rather than polyhedral in shape. Dr. F. T. Bird and his group have lately been studying a most interesting case of double infection, i.e. simultaneous infection of a single animal with both a polyhedrosis and a granulosis. The rickettsiae and the viruses are a group of intracellular obligate parasites that subvert the host-cell metabolism to their own purpose. Witnessing the events inside infected nuclei, although we cannot explain the sequence of events in biochemical terms, we can understand that rup- ture of the cell is in itself a lethal event that leads to malfunction of the tissue or organ and eventually to death of the insect. The entomophilic protozoans comprise quite a large number of obligate parasites drawn from the classes Mastigophora, Sarcodina, Sporozoa, Ciliata and Suctoria. As the class names imply these exhibit a variety of morphological, structural and behavioural differences that are reflected in the appearance of the tissues and organs they infect. For instance, the flagellate Leptomonas occurs in the gut, body cavity and salivary glands of one of the plant bugs but it only occurs in the gut and Malphigian tubules of the corn borer Pyrausta nubilalis Hbn. The flagellates seem to be debilitating rather immediately lethal and this is also true of the 9 -amoebic infections. One of the best known is that of the honey-bee where the Malphigian tubules may become so heavily parasitized that their func- — tion is completely disrupted. Some species of grasshoppers are also so affected and as the disease progresses and the parasites mature, the Malphigian tubules become swollen and rupture. It is obvious that damage to this important excretory organ will have profound physiological effects. — In the class Sporozoa are many parasitic protozoans, including the gregarines, the coccidians and the microsporidians. The latter group, the Microsporidia, have lately received much attention; species of them have been found in a large variety of insects. The late Dr. Hugh Thomson, just before his untimely death, compiled a check list annotating some 130 species of entomophilic microsporidians. As a general statement, micro- sporidian-infected insects may change in colour, size, form, and activity. As the spores of the parasite accumulate in the tissues, the insect may change colour, remain small or dwarfed, or on the other hand become dis- tended or swollen. As the insect harbours ever increasing numbers of the parasite the musclature becomes involved and movement is impaired. It is a common observation that the infected cells increase enormously in size, and this may apply to the nucleus or the cytoplasm or both. However, Thomson has reported that in spruce-budworm (Choristoneura fumiferana Clem.) infected with Perezia fumiferana Thom. this hypertrophy does not occur. Probably the best known of the fungal infections are the Empusa and there can be few entomologists who have not seen, at one time or another, on a windowpane, dead houseflies surrounded with a halo of ejected spores. Infection with rickettsiae, viruses and protozoans is frequently via the gut following ingestion of the appropriate stage of the pathogen, and transovarial passage also occurs. Oral infection rarely occurs with the Empusa spp., although some recent laboratory tests have shown that it is possible. Typically, a conidiospore germinates while adhering to the insect integument and conidial hypha penetrates into the underlying tissues — where mycelium develops. It is still not certain whether this initial invasion of the integument is solely mechanical or whether some enzymatic process is also involved. The mycelium divides into hyphal bodies which multiply by budding and fission until the body cavity is filled with them. Sometimes thick-walled resting spores are formed, so that on diagnosis the infected insect is seen to be filled with hyphal bodies of varied shape and size, or resting spores, or both. Externally, the insect body may be covered with characteristic spore-bearing conidiophores, the general appearance and colour of which varies with the species involved. In the genus Cordyceps there are a large number of pathogens and the sequence of colonization and invasion, while differing in details, is not unlike that of the Hmpusas. Species of the genus Beauvaria attack many well known insects and again the pattern is that of accidental con- tamination of the insect integument with a conidiospore, the germination of this spore giving rise to an invasive germ-tube and then the spread of — the fungus throughout the body of the insect. This fungus can also infect via the alimentary tract. Although there are isolated reports of the production of toxins by entomogenous fungi, it is commonly held that the fungi kill because, sub- sequent to the initial invasion, the fungal mass accumulates using the insect as a substrate. In the early stages of infection the fungus may be spread passively by the blood which constitutes a sort of metabolic pool of nutrients, so that we may think of the fungus multiplying much as it does in a culture tube of broth. At the same time, the mycelial fragments 10 are carried to the organs bathed in the blood and there they become established to set up secondary sites of infection. In some species there is evidence of preferential invasion of particular tissues, especially fat body and muscles. Wherever and in whatever form the organism establishes itself, at that site its extracellular enzymes act on the selected substrate and so we find damage to cells, tissues and organs. To begin with the damaged cells may be replaced or the function dispensed with, but even- tually the damage begins to occur at an increasing rate, and then macro- scopic changes become evident. I have left to the last, reference to the bacteria. They are in some respects the simplest of the insect pathogens. Typically, they have a simple life-cycle; they live mainly as intracellular parasites; most of the known species can be grown on synthetic media outside their hosts and the normal portal of entry is by mouth. In general, infected insects are less active; usually they cease feeding; rectal and oral discharges may occur; and ey After death, the body may change colour, generally to a dark brown or black. There are a large number of species from several bacterial genera that are pathogenic for insects. With many of these there seems to be, follow- ing ingestion, successful establishment of the bacteria in the gut, and the extracellure enzymes produced by the growing bacteria damage the gut so that invasion into the body cavity becomes possible. This breaching of the gut wall is the critical event, for there are many species of saprophytic ' bacteria which are harmless or ineffective if fed but are lethal if they gain access to the body cavity. Once in the body cavity unrestricted growth at the expense of all accessible tissues follows with consequent alterations in pH, oxygen tension, mineral balance, and so on. This is the condition we casually call septicemia. Turning to specific bacterial infections, there are only a few that have been studied in any great detail. Dr. Katznelson has discussed the bee- diseases, and so I shall not refer to them further. For about forty years it has been known that Japanese beetle larvae are susceptible to infectious diseases and about twenty years ago Bacillus popilliae Dutky was shown to be the causative agent of what we now call “milky-disease’’. This or a similar condition also occurs in other Scarabaeid species. Macroscopically, healthy and diseased grubs show few differences until late in the disease cycle when the typical milky appearance becomes apparent. If the body cavity is punctured and a drop of blood is examined, it will be found to contain enormous numbers of the vegetative rods and spores of the causative bacterium. It is the presence of the highly refractive spores that gives the blood its milky-white colour. In nature, the infective spores are ingested with the food and germi- nate in the gut, and the resultant vegetative rods penetrate the gut wall in some way and invade the body cavity where they multiply giving rise to septicemia. Towards the end of the cycle, the vegetative rods sporu- late, and the spores are released with the disintegration of the killed larvae. In spite of the fact that B. popilliae has been used for years as a successful microbial insecticide there has not been, as yet, a definitive study of the histopathological changes in infected larvae. It is doubtful if a rapidly act- ing toxin is involved since moribund infected larvae may contain upwards of two billion spores and still manage to respond, albeit feebly, to stimuli. Bacillus popilliae produces a parasporal body and it is conceivable in the light of contemporary studies with B. thuringiensis, that this body is involved in the initial stages of the infection at least. 1 Bacillus thuringiensis and its varietes have been recognized as insect pathogens for many years and recent studies have shown that the char- acteristic parasporal body or crystal is responsible for the toxic effect. Some purists have suggested that the thuringiensis effect is more akin to a poisoning than a disease and in a few instances this would seem to be the case. However, in many insects we have studied, “disease”? seems to be a more appropriate description. Very soon after ingesting spores and crystals further feeding is in- hibited and this occurs because the mid-gut is paralyzed. It has been shown that there is extensive damage to the mid-gut cells and this damage is thought to be due to a change in the structure of the cell-cementing substances so that in some respects the action in analagous to that of hyaluronidase and the phospholipases. Subsequent to damage of the mid- gut epithelium, vegetative cells of the bacterium can be detected in the body cavity. If lepidopterous larvae which have died following ingestion of spores and crystals of B. thuringiensis are inspected on the microscope, we invariably find enormous numbers of the vegetative phase of the bacterium in all tissues. The picture would seem to be, then, that of a primary toxemia followed by septicemia. If spores alone are injected directly into the body cavity, death from septicemia follows in 12 to 18 hours, and this lends credence to the proposition that the toxic protein which makes up the parasporal body has an invasive function, since spores alone have no effect if fed. In summary then, what kind of injuries do we find in insects suffering from microbial infections? Depending on the pathogen, literally every tssue can be involved. In some of the protozoan diseases a gradual debilita- tion may result as the insect becomes less capable of providing nutrients for its own use and the ever increasing demands of the parasite. Some pathogens affect the function of some particular organ such as the Malphigian tubules, or a muscle system may be impaired, or the ability of the gut to excrete digestive enzymes maybe inhibited. When some bacteria and fungi gain access to the body cavity the nutrient pool is depleted and then specific tissues are destroyed. With some protozoans and viruses, actual physical rupture of the cell occurs, and with a few bacteria, a rapidly acting toxin is involved. There would seem to be no end to this catalogue of effects. As one surveys the literature on insect pathogens its fragmentary nature is immediately apparent. The reason for this of course is not hard to find. Man the biologist has studied man the animal for many hundreds of years and as a result an enormous fund of knowledge has accumulated. In insect pathology, a handful of scientists have attempted to study a group of animals that contain hundreds of thousands of species. It is at once dismaying and intriguing that each host-pathogen system has its own idiosyncracies. Last year at Detroit, Dr. Steinhaus stated that there are more than one thousand known microbial pathogens of insects — and these are but a fraction of those that surely exist. It becomes obvious also that our knowledge of insect disease is uneven in quality. Some of this can be ascribed to the fact that many of the observations were made many years ago before the techniques of electron microscopy, thin-sectioning, cytochemistry and biochemistry had been developed. This is not to infer that the older findings may be disregarded but simply that it might be useful to reinvestigate some of them using these newer methods. Certainly the application of biochemical and cyto- chemical methods should make it easier to discover why a pathogen attacks a particular kind of cell or tissue, and what it does to the cell or tissue. 12 It is characteristic of contemporary studies that we are intrigued with and are seeking to solve what are principally biochemical problems. What is the nature of a particular bacterial toxin; is it a protein, a peptide, or a polysaccharide? Is the toxin a lytic enzyme, or a neural poison? Does the invading fungus produce a chitinase? What are the chemical com- pounds that trigger the germination of Empusa resting-spores? Is the naked DNA of the virus rod infectious? Can we alter host specificity by modifying conditions during viral multiplication? These are only a few of the current problems in insect pathology as it applies to infectious disease. This paper was not intended to be an exhaustive review, and for this reason an extensive list of references is not given. Those interested in additional information on the pathogens mentioned should consult the following: BERGOLD, G. H. (1958). Viruses of insects Jn “Handbuch fiir Virusfor- schung”’, Edited by Halleuer-Meyer. Springer, Vienna. HEIMPEL, A. M. and ANGUS, T. A. (1960). Bacterial insecticides. Bacteriol. Rev. 24 :266-288. STEINHAUS, E. A. (1949). “Principles of Insect Pathology’, McGraw-Hill Book Co., New York. THOMSON, H. M. (1958). Some aspects of the epidemiology of a micros- poridian parasite of the spruce budworm, Choristoneura fumiferana (Clem.). Can. J. Zool. 36:309-316 and also 499-511. (Accepted for publication: February 7, 1961) O INSECT DISEASES RESULTING FROM MALNUTRITION’ H. L. HOUSE’ Insects are subject to noninfectious diseases caused by faulty nutrition and deranged metabolism, which are usually so closely interrelated that a disturbance of nutrition upsets metabolism, and vice versa (45). Specifi- cally, nutritional diseases are those conditions that result usually from a deficiency of one or more essential food constituents. Any perceptible change in the body or its function is a symptom indicating disease; a group of concurrent symptoms form the syndrome characterizing the disease. Unlike the nutritional diseases of man and domestic plants, animals, and fowls, those of insects are not well understood, though, with some exceptions, insects and other animals require the same nutrients (23, 47) for similar metabolic and structural roles. Sang (37) stated that de- ficiences of essential nutrients do not produce particular disease syndromes in Drosophila melanogaster Meig. like those found in vertebrates. For example, deficiencies of certain vitamins resulted in death during the larval stage and often caused high mortality during a particular instar; deficiencies of other vitamins resulted in death during the developmental iPpresented as part of a symposium on insect pathology to the 97th annual meeting of the Entomolo- gical Society of Ontario, Guelph, Ontario, November 23-24, 1960 2Entomology Research Institute for Biological Control, Research Branch, Canada Department of Agriculture, Belleville, Ontario. _ Proc. ent. Soc. Ont. 91 (1960) 1961 13 crisis of the pupal instar, but whenever adults emerged their appearance was invariably normal though small in size. According to Gordon (18), one of the most striking features of insect nutritional research is the difficulty of producing deficiency symptoms like those in mammals. Reviews of insects nutrition (14, 24, 25, 32) lists many investigations in which the only symptoms of malnutrition found were decreased size, and decreased rates of growth, development, and reproduction. These common terminal effects of malnutrition need not be discussed further in this symposium. This paper is mainly on characteristic abnormalities arising from deficiencies and excesses of specific nutrients as observed in certain insects. DISEASES: CAUSE AND SYMPTOMS Starvation Starvation is a severe general deficiency. Starved insects may survive for periods ranging from a few days to many weeks depending on the species, the stage of development, and the nutritive reserves in the body. The depletory effect of starvation on nutritive reserves has been deter- mined in several insects (86, 51). In most insects starvation begins with the loss of carbohydrate as shown by the rapid depletion of glycogen from the tissues; proteins may be extensively utilized in some species and not in others, but fat is always the chief reserve substance and 50 to 90 per cent of the fat may disappear before death occurs (45). Histochemical techniques showed that glycogen, protein, and fat were used concurrently in Aedes aegypti (L.) larvae during starvation; that in 10 to 15 days all the stainable fat disappeared and glycogen was absent or present in minute traces only in the sarcoplasm; nuclei and cytoplasm in all the tissues were much wasted, and the ultilization of protein was marked by a progressive accumulation of uric acid in the aqueous vacuoles of the fat body (52). Heron (20) stated that individual starved larvae of the larch sawrfly, Pristiphora erichsoni (Htg.) may be readily recognized on examination of their fat body cells when stained for cytochemical differentiation of lipids. Cells of the fully fed larvae were heavily laden with large fat in- clusions; in partially starved larvae the fat globules were dispersed, smaller in size, and usually peripheral in position. Moreover, the water content of the larvae increased with the extent of starvation. Bursell (6) showed that the well fed tsetse fly Glossina morsitans Westw. contained much alanine and glutamic acid, small amounts of arginine, taurine, and serine, and very little glutamine and aspartic acid. In the starved fly the general ninhydrin postivity was greatly decreased : the amounts of most of the amino acids and related substances were decreased, and ornithine had appeared. He also reported some differences in the relative concentration of amino acids between fed an starved in- dividuals of Musca. sp., Lucilia sp., and Apis mellifera L. Work at Belleville shows that insects may appear superficially well nourished though fundamentally they are suffering from malnutrtion. For example, good growth of Agria [= Pseudosarcophaga] affinis (¥all.) and reasonably good growth and reproduction of Musca domestica L. have been reported on chemically defined diets (26, 27). However, the fat cells, mid-gut epithelium, and muscular tissue of these insects have a “starvation- like” appearance and the embryonic development of most eggs in A. affinis is arrested in the blastular stage (Bronskill, unpublished). Larvae of A. affinis reared on the synthetic diet retain about 10 per cent more water, and their hemolymph has less protein than those reared on a satisfactory 14 i - ae z : food, pork liver, though the electrophoretic pattern of the protein is the same (Barlow, unpublished). The deficient substance, or imbalance of substances responsible for the faulty nutrition has not been determined. Adequate nutrition for growth may not be optimal for the organism, as the Belleville work shows. Starvation may result from poor food for want of suitable intake of nutrients affecting normal metabolism and the synthesis and disposition of body material. From what is known of the syndromes of nutritional diseases in insects the specific cause of mal- nutrition cannot always be determined. But many of the symptoms of specific deficiencies are similar to those found with starvtion, depending on how widely metabolism is affected. Proteins and Amino Acids Lack of nitrogenous food is a cause of paralysis in adult honey bees, Apis mellifera, especially nurse bees (7). Those not receiving enough nitrogenous food deplete their body reserves of this material, their chitin becomes brittle, their hair is lost, and their wings may break off. In other work with Periplaneta americana (L.) very high levels of dietary protein (91 per cent) resulted in visible white deposits presumably of urates or uric acid in the legs, head, and other parts of the body; the abdomen was greatly distended, and the white mass of the fat body hardened very quickly on exposure to air (29). Excess dietary protein upset the metabolic balance in Drosophila melanogaster (37). Tumor incidence increased in strains of this insect fed too much of the amino acids phenylalanine (49), arginine (50), tryptophane, tyrosine, and the amine asparagine (35). Various shades of pigmentation in Aedes aegypti larvae may be produced by varying levels of phenylalanine and tyrosine in the diet, but the adults reared were always normally pigmented (16). Carbohydrates Excessive amounts of carbohydrates in the diet had injurious effects on some insects, such as Drosophila melanogaster (37), Musca domestica (19), and the screw-worm, Callitroga hominivorax (Cqrl.) [=C. ameri- cana (C. & P.)| (34). Dietary levels of glucose higher than one per cent overcome the ability of A. affinis larvae to limit hemolymph carbohydrate to the usual level (2) and this produced detrimental effects on growth (26). The response of certain insects to carbohydrates may be related to some extent to the amount of protein present (5) and to other dietary components (37, 38). Thus, the metabolic balance of insects may be upset by unsatisfactory dietary levels of carbohydrate and result in deleterious effects. Histopathological or morphological syndromes of carbohydrate malnutrition have not been determined specifically in published work, though the effects of various carbohydrates on glycogen synthesis and deposition in the tissues are reported (52). Lipids It is generally found that a sterol is the only lipid or fat-soluble substance required in the food of insects (47). Without sufficient quanti- ties of a suitable sterol, such as cholesterol, all insects cease to grow, develop, or survive. However, Silverman and Levinson (41) described other symptoms of a sterol deficiency in Musca vicina (Macq.). They observed that the larvae reared on sterol-deficient diets included many that were flacciform and unable to resist infection from pathogenic bacteria. Hobson (22) also reported that resistance of blowfly larvae, Phaemcia [= Lucilia] sericata (Meig.), to bacterial infection was corre- lated with dietary cholesterol. 15 Fraenkel and Blewett (10) found that linoleic acid was essential in Ephestia ktuhniella Zell. for development of wing scales, expansion of wings, and emergence of the moths. The extent of abnormalities in these processes was proportional to the deficiency. Certain anologies were pointed out between the effects of linoleic acid deficiency in the insect and the rat. Faulty moth emergence, malformed wings, and undeveloped wing scales were reported also in pink bollworm, Pectinophora gossypiella (Saund.), on fat-deficient diets (4), but this was not confirmed in more detailed work later (48). The symptoms of linoleic acid deficiency in Blattella germanica (L.) were described as follows: the egg cases were usually aborted; but when nymphs hatched from the eggs, they showed characteristic deficiency symptoms, such as erratic walking, falling, and lying on their backs with weak agitation of legs and antennae until death occurred in a few days (18). It was shown that Tenebrio molitor L. readily - synthesized linoleic acid and needed no dietary source (11). Other work showed that Agria affinis had no need for dietary sources of linoleic acid or other polyunsaturated fatty acids; certain fatty acids, however, acceler- ated the growth rate, but no other effects were observed (28). Actually few insects have been found to need dietary fats. Vitamins Observations have been made on the effect of vitamin deficiencies in insects other than those on growth and metamorphosis. On thiamine- deficient diets larvae of the rice moth, Corcyra cephalonica Staint., accu- mulated large amounts of pyruvic acid in their tissues (40) as vertebrates do. Various degenerative changes occurred (46). Histological examination of the larval tissues showed poor development of the muscular system and adipose tissue, and unusual globules in the mid-gut epithelium of five day old larvae. The cytoplasm of 30 day old larvae was vacuolated, the lipid globule appeared at random in the cytoplasm and tended to increase in size, the nucleus was enlarged and distorted in shape against the cell wall, and the number of nucleoli increased. Finally, the nuclei of the mid-gut epithelial cells reached acute stages of degeneration; their chromatin, no longer Feulgen-positive, was clumped in a corner of the nuclear membrane. On thiamine-deficient diets Tribolium confusum Duv. had small cells with low lipid content and other degenerative symptoms in the fat body; ribo- flavin-deficient diets had no apparent effect on any of the tissues (15). The symptoms of a deficiency of carnitine, or vitamin By, have been described fully in Tenebrio molitor larvae (12). The symptoms of this deficiency depend on the age of the larvae. In young larvae feeding pro- ceeded normally and they molted every five or six days but usually death occurred after the seventh molt, whereas in older larvae, made deficient at an age of eight to twelve weeks, death was not associated with the period of molt. The cuticle of both young and old was affected and water was quickly lost. In young larvae the cuticle did not darken after the last molt preceding death. Also, the cuticle of the adult, derived from a larva reared on suboptimal levels of carnitine, was neither properly formed nor fully darkened in color. Moreover, the wings of such adults did not expand normally. Most affected by carnitine deficiency were the tanning of new cuticle and the regulatory system controlling water loss. Examination of the larval tissues showed changes in the oenocytes, mal- pighian tubes, hemolymph, and fat body but not in the neural and muscular systems (8). For example, there was a clumping of chromatin and dis- organization of the cytoplasm in the oenocytes, and a degeneration of the epithelia of the mid-gut; also crystals of uric acid or its salts occurred in 16 _ the intestine. Similar-conditions were found in starved larvae but they did not arise as quickly (8). Possibly the only insects that require dietary sources of carnitine are certain beetles of the family Tenebrionidae (21). _ Recent work showed that expression of carnitine deficiency depended on the kind of salt mixture used as zinc and potassium were involved (9). Pathological conditions arising from vitamin deficiencies in the larvae, pupae, and adults of Musca vicina were demonstrated by Levinson and Bergmann (31). Deficiencies of either pyridoxine or nicotinic acid caused by antivitamins resulted in larvae that moved unusually slowly, lacked appetite, suffered from heavy diarrhoea, and invariably died in a typically paralysed position. According to these workers, the symptoms appeared to be rather specific for a deficiency of these two vitamins and resembled a larval disease of Bombyx mori L. referred to as “‘dysenterie flaccidi- forme’. A slight deficiency of any of the six essential vitamins permitted larval growth, but abnormal pupation occurred. The puparia did not form their typical oval shape, and the flies were not always able to free them- selves from their puparium or to remove their wings from the pupal skin. Some adults developed from biotin-deficient larvae were unable to spread their wings and fly. Adult females fed on milk containing various anti- vitamins died mostly in a distorted position with their ovipositors erect, their alimentary tracts were filled with undigested milk, and though they had mated their ovaria contained no eggs. In the rice moth, Corcyra cephalonica, lack of pyridoxine upset tryptophane metabolism as the feces of the larvae reared on a pyridoxine- deficient diet with extra tryptophane were yellow, but with pyridoxine present they were a normal white (39). The larvae fed on a biotin- deficient diet excreted less uric acid than those grown on adequate diets (43). The tissues of biotin-deficient larvae did not desaturate palmitic and stearic acids as well as those of larvae fed biotin; and there was less fat and cholesterol, and a greater accumulation of nitrogen than in the tissues of biotin-fed larvae (42). Work with Aedes aegypti showed that larvae reared on a folic acid- free diet were unable to free themselves from their third instar integument and only their heads were pigmented (17). Other work showed that certain individual vitamins and multi-vitamin dietary supplements in- creased tumor frequency in Drosophila melanogaster (18). SIGNIFICANCE OF SYMPTOMS Since nutritional requirements depend on the synthesizing abilities of the organism, symptoms of malnutrition throw light on the metabolic role played by different nutrients inasmuch as the raw materials for all the chemical changes going on in the cells and tissues arise from the products of digestion. In some cases, as with a deficiency of thiamine (40) the metabolic products that accumulate in the tissues of the insect are the Same as those that arise in mammals. : Starved insects commonly show a loss of nutritive reserves; with the depletion of glycogen, fats, and proteins from the tissues, the cells begin to degenerate, However, abnormalities similar in many respects to those in starved insects may arise in feeding insects when metabolism is impaired by a deficiency, a critical imbalance, or an absence of various nutrients in the food. Symptoms may be misleading as to the cause since our present under- standing of them is imperfect. For example, the accumulation of uric acid or urates in insect tissues is a symptom of starvation (52), of ingestion of very high levels of protein (29), of a deficiency of carnitine (8), and 17 presumably of a deficiency of biotin (48). In the cockroach fed high pro- tein diets (29), for example, the accumulation of urates or uric possibly may have been due to a deficiency of certain vitamins, such as biotin, because an imbalance was created between protein and the vitamins needed to metabolize it. It is possible that no such symptom would have appeared had an increase in vitamin levels been made commensurate with the increased protein levels. Thus, though the connection between certain abnormalities and nutritional fault may be unique and direct, that of others may be complex. Moreover, some symptoms seem to be peculiar to the insect concerned. For example, the two lepidopterans, E'phestia kiihniella and Pectinophora gossypiella, shown to require linoleic acid do not exhibit the same deficiency symptoms (10, 48). Many of the symptoms reported may help to distinguish between insect diseases caused by nutritional defects and those caused by micro- organisms. To characterize the nutritional diseases with certainty it is necessary to recognize a group of concurrent symptoms. The syndrome of various nutritional diseases in insects awaits determination, Probably it will have to be done for each species or closely related group of insects. But until it is done and until more is known about nutritional diseases of insects in general neither the subject of insect nutrition nor insect patho- logy is complete. Certainly insect nutritionists should report all abnormali- ties arising from malnutrition. NUTRITIONAL DISEASE AS A FACTOR IN CONTROL Though specialization has tended to restrict most insects to one or a few natural foodstuffs, the diet is not always optimal. In natural environ- ments nutritional disease in insects may result from deficiencies of food, as Shown by Heron (20), and from variations in the composition of the food. It has been shown that some food plants are not utilized as well as others (44): consumption, excretion, and increase in dry matter and nitrogen in the body tissues differed with the kind of plant (30). The pea aphid, Acyrthosiphon pisum (Harris), encountered nutritional diffi- culties, reducing its rate of growth and reproduction, on resistant varieties of peas, which contained less nitrogen, lower concentrations of amino acids, and more sugar than susceptible varieties (1, 33). Other work, recently reviewed (24, 25), showed that the nutritive value of natural foods varied with consequent effects on the insect. Satisfactory propor- tional relationships between nutrients are necessary because quantitative requirements for many substances depend on the intake of others. In Drosophila melanogaster the quantitative requirements of all but two of the vitamins were affected by dietary protein levels (38). Gordon (18), discussing “food efficiency’, pointed out that a diet that is optimal in the early period of growth is likely to be subcptimal in the later period, and vice versa, When superoptimal proportions of various nutrients are ingested, excesses must be eliminated and/or other substances entering into metabolic processes must be provided commensurate with the need. Deficient and unbalanced diets are not utilized efficiently and metabolism proceeds under strain more or less detrimentally affecting the vigor of the organism. Such conditions decrease the survival rate of insect popu- lations. Nutrition also is an accessory to other means of control. According to Bass and Rawson (3) natural tolerance to insecticides often has been confused with heritable resistance. They showed, however, that the food of the adult boll weevil, Anthonomus grandis Boh., ranked highest among several factors affecting the susceptibility of this insect to three in- 18 secticides. Probably mortality is increased by nutritional circumstances that reduce the normal resistance of an insect to parasites, infectious diseases, and inclement weather, or that prolong the exposure of weakened insects to adverse environmental conditions. In natural environments the quality of the food is as important as the quantity. CONCLUSIONS At present one must regard the effects of nutritional diseases as being more or less peculier to the insect concerned. Until more work is done on the nutritional diseases of insects there is little scope for signifi- cant generalizations. This subject is neither merely one of academic interest nor an esoteric one reserved for insect pathologists. With the quality of food as important to an insect as the quantity, effects of nutrition may illuminate the research of nutritionists, physiologists, bio- chemists, ecologists, and others. As evidence, nutritional techniques were used as diagnostic tools on metabolic pathways. Perhaps of greater signifi- cance is the role malnutrition plays in insect control. SUMMARY Mainly biochemical and histological symptoms of starvation and of dietary deficiencies of specific nitrogenous substances, carbohydrates, lipids, and vitamins determined in different insects are reviewed. Various symptoms of nutritional diseases are reported in 19 of the 22 species mentioned. The symptoms of specific deficiencies in different insects are not always similar. The present paucity of information limits the scope of significant generalizations. However, the significance of the role played by malnutrition in the control of insects is discussed. ACKNOWLEDGEMENTS I am grateful to Drs. Joan F. Bronskill and J. S. Barlow for per- mission to quote their unpublished work. LITERATURE CITED (1) AUCLAIR, J. L., MALTAIS, J. B. and CARTER, J. J. (1957). Factors in resistance of peas to the pea aphid, Acyrthosiphon pisum (Harr.) (Homoptera: Asphididae). I] Amino acids. Canad. Ent. 89: 457-464. 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SmiTH, D. S. (1959). Utilization of foodplants by the migratory grasshopper, Melanoplus bilitwratus (Walker) (Orthoptera: Acridi- dae) with some observations on the nutritional value of the plants. Ann. ent. Soc. Amer. 52: 674-680. STEINHAUS, E. A. (1949). Principles of Insect Pathology, Ist ed. pp. 69-82. McGraw-Hill Book Co: Incey.Ney: 21 (46) SwAmy, B. G. L. and SREENIVASAYA, M. (1942). Studies in insect nutrition: Symptomology of avitaminosis in Corcyra cephalonica, Staint. — a histological study. Curr. Sci. J7: 147-148. (47) TRAGER, W. (1953). Nutrition. In Insect Physiology, ed. by K. D. Roeder, pp. 350-386. John Wiley & Sons, Inc., N.Y. (48) VANDERZANT, E. S., KERUR, D. and REISER, R. (1957). The role of dietary fatty ‘acids in the development of the pink bollworm. J. econ. Ent. 50: 606-608. (49) WILSON, L.P. (1947). Effect of dinitrophenol and excess amino acids upon melanotic growths in Drosophila. Anat. Rec. 99: 600 (abstract). (50) WILson, L. P. (1949). Increased incidence of a tumor of Drosophila in the presence of high concentrations of arginine. Anat. Rec. 105: 627-628 (abstract). (51) WIGGLESWoRTH, V. B. (1939). The Principles of Insect Physiology, pp. 825-353. E. P. Dulton and Go. Inc., N. Y. (52) WIGGLESWORTH, V. B. (1942). The storage of protein, fat, glycogen, and uric acid in the fat body and other tissues of mosquito larvae. J. exp. Biol. 19: 56-771. (Accepted for publication: November 30, 1960) Qe MICROBIAL INFECTIONS OF THE HONEYBEE AND THEIR CONTROL’ H. KATZNELSON”® In common with other forms of life the honeybee is susceptible to a variety of infections caused by viruses, bacteria, protozoa, fungi and even other insects. Losses due to these agents may amount to millions of dollars annually: to the beekeeper as a result of decreased honey yields and loss of equipment, and to the fruit grower and seed producer as a result of the decreased pollinating potential of diseased colonies. Control measures over the years have varied from fumigation or dipping of hive equipment in boiling lye solutions, manipulative procedures such as shak- ing bees from infected to clean comb, adding brood and requeening to outright burning of the hive and its contents. In recent years chemo- therapeutic agents such as sulpha drugs, antibiotics and arsenicals have become popular though by no means the panacea that was hoped for. It is my purpose to describe that most important microbial diseases of the honeybee and to discuss their control by therapeutic means. BROOD DISEASES | Representatives of nearly all forms of microscopic life produce diseases of bee larvae. Sacbrood This is a disease of larvae caused by a filtrable virus. We have verified this experimentally. The larvae die after the cells are capped and remain stretched out along the length of the cell; the head ends are shrivelled and darkened, curling upward and the body contents are watery. The disease is usually controlled by the bees. It is quite prevalent but not regarded as serious. 1Presented as part of a symposium on insect pathology to the 97th annual meeting of the Entomological Society of Ontario, Guelph, Ontario, November 23-24, 1960. 2Microbiology Research Institute, Research Samet Canada Department of Agriculture, Ottawa. Proc. ent. Soc. Ont. 91 (1960) 1961 99 Chalk Brood and Stone Brood These two fungal diseases are caused by Pericystis apis and Asper- gillus flavus, respectively. In chalk brood the larvae become permeated with the mycelia of the fungus and die soon after the cells are capped. The dead brood is chalky white in appearance and looks mummified. In stone brood, the mould transforms the larvae into hard stone-coloured objects lying in open cells. Even adults may be attacked and killed. Neither disease is considered serious although it may be spread from one colony to another, The two most severe diseases of honeybee larvae, American foulbrood (AFB) and European foulbrood (EFB), are caused by bacteria. Their distribution is world wide but American foulbrood was first described in the United States whereas European foulbrood was first described in Europe, hence the names. American Foulbrood I think I am correct in stating that AFB is the most widespread and destructive of the brood diseases and indeed of all diseases of the honeybee. It is caused by Bacillus larvae, a spore-forming organism and is most diffi- cult to erradicate. The spores are taken up by young larvae in their food. They germinate in the intestinal tract but do not appear to develop extensively in it. Rather they penetrate the epithelial lining of the gut, possibly by means of the powerful proteolytic enzymes they produce and invade the body cavity in which they multiply extensively, producing, according to some workers, a type of septicemia, and finally killing the larvae. Soon after the larva has assumed its longitudinal position in the cell and is capped over, it dies. It is interesting that only young 2- to 3-day old larvae are susceptible. This was thought to be due to the nature of the food supply since at this time the larval food changes from royal jelly to honey and pollen. In order to resolve this point the late Dr. Jamieson and I tried infecting queen larvae at different stages of growth, since their food consists of royal jelly throughout their development. However, even with these, susceptibility ceased at 2.5 days. Further work to resolve this inter- esting problem is certainly warranted. After death of the larvae the bacteria, having used up all the available food, turn into spores again except that whereas at the beginning a few thousand or more may have been ingested there are now 1 to 2 billion per larva. The house-cleaning bees in trying to remove the dead remains succeed usually in spreading the spores throughout the hive and the cycle begins over again. More larvae become infected and gradually the colony becomes so weak that sconer or later it dies out. Associated with the collapse of the larva are changes which char- acterize the disease and are of importance in its diagnosis. The capping of the cell becomes dark and sunken often with a hole showing attempts of the worker to remove the contents. The larva changes from pearly-white to a darker and darker brown, becoming slimy and ropy and may be drawn out as a thread. At this stage it develops the characteristic glue pot or burned glue odour. Finally it becomes tacky and dries to a dark brown or blackish adherent scale composed of spores of B. larvae plus proteinaceous material including proteolytic enzymes. The spores of B. larvae are extremely resistant to heat, cold, drying, irradiation and disinfectants and burning is about the only certain way of destroying them. I have been testing their viability for Dr. Haseman of 23 Missouri and find that AFB material 35 years old, still contains millions of viable spores. An interesting feature of this larval scale is its relative freedom from other bacterial contaminants and indeed Holst, of the United States Department of Agriculture, has reported that it contains an antibiotic which effectively suppresses a variety of bacteria. Bacillus larvae itself is a rather interesting organism. In nutritional studies we have shown that it requires vitamin B: for growth; a purine base, such as xanthine, guanine or adenine is essential as are certain amino acids. It grows well when aerated but respires primarily via the glycolytic or fermentative pathway. Spore production in laboratory media is usually hard to demonstrate but the spores germinate readily with a rather sharp pH optimum at about 6.6 to 6.8. The organism itself is susceptible to a virus disease, bacteriophage, but since not all of the cells are destroyed by the virus it cannot be used for control. It may be used, however, to deter-_ mine the distribution of specific strains of B. larvae over wide areas. Because of the resistance of the spores, drastic measures are required to destroy them and to control the disease. Apiary inspectors are em- powered by law to burn the colony and its contents even if one infected larva is found. Fumigation, boiling in lye solutions and other laborious methods have all been used with varying success. Another obvious means of control is by the production of resistant strains of honeybees and indeed this has been attempted. However, it was found that resistant bees were not truly resistant, rather they appeared to be better housekeepers, removing diseased brood before the usual symp- toms developed, and presumably before the vegetative cells of Bacillus larvae could sporulate. In its vegetative or rod forms this bacterium does not cause the disease. Rothenbuhler of Iowa State University has recently reported on an AFB-resistance factor possessed by certain larvae and not others. I have no further information on this point but this would be a most desirable solution to the AFB problem. In 1944 Haseman and Childers introduced sulpha drugs as an effective means of controlling and, they claimed, of curing AFB-infected colonies. Since their first report, these drugs have been used extensively, usually at the rate of 500 mgm. per gallon sugar syrup applied as a spray or as food or dusted in powdered sugar, with gratifying results which we have repeated time and again, but only as a prophylactic or control measure. I am not prepared to commit myself as to the effectiveness of these drugs as cures of obviously infected colonies; arguments pro and con are still going on. When antibiotics became available in quantity they were also tested. Of the many used, terramycin and related types were found to be effective for a season but in our hands the sulpha drugs were still the best because of their greater stability. We found, for example, that these compounds were still completely effective against AFB after 3 years’ storage in honey at room temperature whereas terramycin had lost its effectivness after 30 days under the same conditions. European Foulbrood This is a bacterial infection of young larvae which kills when they are about 4 days old and therefore neither extended in the cell nor capped. The organism develops within the alimentary canal close to the surface of the peritrophic membrane. The bacterial mass eventually extends to- ward the centre of the lumen of the peritrophic sac, more or less filling it. The host tissues do not appear to be invaded and it has been concluded that death is caused by toxic products produced by the organism which diffuse through the intestinal wall. Many types of bacteria are often found in 24 the dead larvae and the symptoms also vary considerably so that the picture of the disease is much less uniform than with AFB. The most con- spicuous and most frequently encountered organism in the early stages of the disease is Bacillus pluton, now more correctly called Streptococcus pluton. This is a lanceolate coccus often found in packets. A small rod- shaped organism, Bacterium eurydice, is so often found in association with S. pluton that over the years and and even as recently as 2 years ago it was considered that both organisms had to be present to cause the disease; other workers considered one a stage in the life cycle of the other. Another bacterium, Bacillus alvet, is also very common in infected material al- though it is considered to be a secondary invader, proliferating on the decomposing larvae. It is curious that this organism is found only in association with EFB and none of the other brood diseases; in fact it is a useful diagnostic aid in detecting this disease because of the characteristic arrangement and appearance of the spore—usually with a small sporangial fragment attached to it—and because of its ability in colony form to move over the surface of an agar plate. However, I must emphasize that it has not been found to be pathogenic in field trials. Returning to Streptococcus pluton. For years it had eluded isolation and was considered an obligate parasite. However, Bailey of Rothamsted now claims to have isolated it with relatively little difficulty. He has described it as an anaerobe with a high requirement for potassium and phosphorous in the medium. On the other hand a group of workers at the University of Wisconsin claim to have isolated an organism which they have identified as S. fecalis and which causes disease of bee larvae cultured in the laboratory. Although the disease symptoms do not appear to be the same as those observed in the hive it is considered that this is due to the absence of other bacteria (B. ewrydice, B. alvei, etc.) which confuse the picture. Their cultures are very similar to another coccus frequently isolated from EFB material, S. apis. This organism has also been called S. liquefaciens and is very closely related to and possibly identical with S. fecalis. It may be that S. pluton is really a pathogenic strain of S. fecalis just as Bacillus cereus var. thuringiensis or var. — anthracis are pathogenic strains of B. cereus. When the larva is infected with EFB it moves about inside the cell and at death is found in unnatural positions. Its colour becomes brownish and it eventually dries up to form a loosely attached brown scale; it is not usually ropy and its odour varies from foul to sour depending upon the nature of the secondary invadors, The disease may spread extensively in a colony and eventually kill it or it may be cleaned out rapidly by the _ bees. It is able to survive severe winters and may reappear in the spring. Bailey has reported that it resists desiccation over long periods. Methods of control vary from re-queening to strengthening the colony by supplying additional bees or even to burning as with AFB. Strangely enough sulpha drugs do not seem to control EFB; however, streptomycin, terramycin and a number of other antibiotics applied as dusts, sprays or in honey as food can control it. Terramycin is effective against AFB as well and therefore is a very useful dual-purpose compound. MICROBIAL DISEASES OF ADULT BEES I have used this title in order to exclude a serious disease of bees “Isle of Wight” or “Acarine’”’ disease caused by a mite, Acarapis woodt. This is widespread in Britain but has not appeared in Canada. There ap- pears to be some question as to its presence in certain areas in the United States. However, this may be a matter of mistaken identity because of the 25 similarity of this mite to others such as Acarapis externus which are not parasites. Nosema Disease | This is the most common adult bee disease in Canada and in the United States and is caused by a protozoan, Nosema apis, which infects the alimentary canal of the bee. The infection weakens the colony in the winter and in the spring and is considered to be partly responsible for queen supersedure. The overall result may be a serious reduction in the productivity of the colony. The spores or cysts of this organism are ingested and pass into the ventriculus or mid gut, where they germinate and the amoeba-like organ- ism penetrates the epitheleal cells, grows and multiplies therein finally changing into spores again. The rupture of the host cells liberates the cysts into the mid-gut and they are carried on eventually to be eliminated in the excreta. The accumulation of these spores in the rectum may be readily observed with the microscope and this is probably the most certain method of diagnosis. The infected bees lose their ability to fly, and crawl about outside the hive with wings extended. They may show no obvious signs of trouble even though infected but the colony gradually declines in strength due to an abnormal loss of bees which die during foraging. Re- queening and strenthening the colony by supplying additional brood usually relieves the situation, Fumigation of the combs with 80% acetic acid is efficacious. The infection may be controlled also, though not completely eliminated by means of drugs. We have done considerable work in this connection using a variety of antiamoebic substances from sulpha drugs and anti- biotics to atabrine and emetine, without too much success. However, in 1952 we found that a new antibiotic, fumagillin, in amounts of 1 part in 30,000 reduced infection markedly. This compound is being used in various parts of the world with considerable success. Recently we tested several other antiamoebic antibiotics — Paramomycin (Humatin) and Streptimi- done. The latter was quite toxic and was discarded. Humatin showed con- siderable promise at first but further tests were unsuccessful. Another protozoan, Malpighamoeba mellificae, causes the so-called amoeba disease, an infection of the excretory organs, the Malpighian tubules. In many respects it resembles Nosema disease but it is not so prevalent. Its cysts are spherical and may be observed microscopically in the tubules. It may be controlled by the same cultural and fumigation procedures as for Nosema; however, I am not aware of any drug treatment which has proved successful. A bacterial disease of adult bees has also been described but there has been relatively little work on it. The organism, Bacillus apisepticus invades through the tracheae and is presumed to cause an acute septicemia. In recent work we have shown that this organism is not a bacillus at all, and produces no spores. It is, in fact, related to Pseudomonas aeruginosa a well known pathogen of insects such as the silkworm, wax moth and grasshopper. Antibiotics such as terramycin have been reported to control this disease, although we have not been overly successful in this connection. Many other micro-organisms have been isolated from larvae and adult bees, including spore-forming and no-spore-forming bacteria and yeasts. They are mostly inhabitants of the intestinal tract and may or may not contribute to the health of the bee. This is an area which requires further investigation. (Accepted for publication: December 5, 1960) 26 PATHOLOGICAL CONDITIONS IN INSECTS RESULTING FROM CHEMICAL AND PHYSICAL INJURY’ E.. H, SALKELD® Pathological conditions, defined as abnormal structural and functional changes, occur in all living organisms when they are injured by chemical agents such as insecticides. Much of the early work in insect pathology was mainly descriptive, dealing with the symptoms displayed by a poisoned insect and with the structural changes, as evidenced by histological ab- normalities, that occurred in various tissues and cells. It is obvious that these conditions are the result of some abnormal physiological condition in the insect which, in turn, is the result of some physical or metabolic de- rangement in the cells of the organism. Thus, the study of the pathological conditions resulting from insecticide action has become inextricably in- volved with the study of the basic physiological and biochemical processes of the body. A lack of knowledge about these processes in insects has severely handicapped pathological and toxicological research; if the normal is not known, how can the abnormal be recognized? A discussion of the pathologic conditions occurring in poisoned insects invariably evolves into a discussion of the mode of action of insecticides; such will occur in this paper. A few of the symptoms and structural changes that occur will be very briefly outlined and mention made of their relevance to insecticide action. For a much more detailed review of this subject, reference should be made to the work of Steinhaus (31) and Brown (8). In the last part of the paper some of the more recent developments in insect pathology, which deal mainly with functional ab- normalities resulting from insecticide action, will be mentioned. Advances in this field have been due, in great measure, to the use of a biochemical approach with its tissue brei methods. Since these methods are somewhat lacking in specificity, future developments appear likely to involve tech- niques capable of analysing metabolic abnormalities within an intact cell. BEHAVIOUR OF POISONED INSECTS An insect affected by an insecticide usually exhibits certain symptoms of distress. The type of symptom elicited has been used to classify in- secticides as to their mode of action. Thus, those insecticides which cause the insect to become active and excited, to have convulsions, to become paralysed and finally to die, are usually considered to be nerve poisons. Pyrethrum is a classic example of this type; the progressive symptoma- tology of pyrethrum-poisoned bees has been described as restlessness and frantic flying, ataxia, complete paralysis, and death (7). The initial phase of excitation is thought to be caused by stimulation of the peripheral nervous system, the ataxia by stimulation of the central nervous system, and the paralysis and death by destructive pathological changes in the nervous tissue. Other so-called nerve poisons which induce similar symp- toms in insects are the organophosphate compounds and the chlorinated hydrocarbons such as DDT. DDT-poisoned insects show, in addition, a characteristic tremor known as the “DDT’s” or the DDT “‘jitters’’. Insects affected by fumigants, such as hydrogen cyanide and other respiratory poisons, exhibit a rapid narcosis from which they may or may not recover when removed to a fumigant-free atmosphere. However, if ipresented as part of a symposium on insect pathology at the 97th annual meeting of the Entomological Society of Ontario Guelph, Ontario, November 23-24, 1960. 2Entomology Research Institute, Research Branch, Canada Department of Agriculture, Ottawa, Ontario. Proc, ent. Soc. Ont. 91 (1960) 1961 27 the insect recovers, it may then display all the symptoms elicited by a “nerve poison’. It can be seen that the term “nerve poison’, when applied to an insecticide on the basis of the gross symptomatology displayed by an insect poisoned with it, is rather nebulous and to some extent meaning- less. Some of these “nerve poisons” are known to affect other organs and tissues as well as the nervous system and the exact site of their lethal action is not known. Actually, the symptoms displayed by a poisoned insect depend largely on the method of application and the concentration of the insecticide. They may also vary with the species and stage of development of the insect. Although symptoms are fundamental clues to the action of an insecticide, it is rather hazardous to draw conclusions from the symptoms alone. EFFECTS OF INSECTICIDES ON ORGANS AND CELLS Heart and Blood In addition to the peculiar actions performed by a poisoned insect, certain organ systems, such as the circulatory system, may also behave in an unusual fashion. For example, in some insects the rate and the ampli- tude of the heart beat may be increased during poisoning, the synchrony of the beat may be destroyed or the direction of the beat may be reversed. On the other hand, complete cessation of the heart action may occur al- though this inhibition is not necessarily fatal. Comparatively little effect on the heart beat occurs after poisoning with the organophosphates and chlorinated hydrocarbons (21). The significance of these observations as a clue to the site and mode of action of an insecticide is rather vague since they could be the result of injury to almost any part of the insect. Much valuable information has been accumulated recently concerning the © physiological and biochemical functioning of the heart before and after poisoning with drugs and insecticides; this work will be mentioned later in this paper. In addition to the visible effect on the heart, a change in blood volume and in the structure of the haemocytes may also occur during poisoning. Several workers have noted marked changes in the haemocytes in poisoned insects including agglutination, distortion, disintegration, and a decrease in total cell number. Jones (18) noted a slight decrease in the number of plasmatocytes in DDT-poisoned mealworm larvae and Arnold (1) men- tioned a smiliar occurrence in fumigated Mediterranean flour moth larvae. Pathological conditions in insect bleod cells are rather difficult to detect since the general form of a normal cell changes continually. The situation is additionally complicated because insect haematologists have not yet established a unified blood cell classification. An interesting condition has recently been described by Sternburg et al (32) in DDT-poisoned cockroaches. They found a toxic substance in the blood which was not a metabolite of DDT and suggested that it was a natural neuroactive component of the insect’s body released into the blood only after the insect has been affected by certain definite stimuli. Blood from these roaches is also toxic to other insects, and there is speculation about its possible use as a neurotoxic agent for control purposes (9). How this substance is formed and released into the blood is not known, but its formation is more likely to be the result, rather than the cause, of the initial DDT symptoms (37). Respiratory and Tracheal System The rate of respiration is usually either increased or decreased by insecticide since it is a measure of the metabolic activity of the cells of the insect. Thus an initial marked rise in oxygen consumption usually occurs in 28 3 ae insects affected by ‘“‘nerve poisons” such as DDT which cause initial hyperactivity of the insect. Conversely, a depression in the respiratory rate may occur in insects affected by the fumigant hydrogen cyanide, which causes a rapid knockdown. On the other hand, the respiratory rate may not show any abnormality until several hours after the insect has been treated with the poison and, indeed, may never show any (17, 19). Although there appears to be a close correlation between the motor activity of a poisoned insect and the variations in its respiratory rate, these vari- ations are usually considered to be secondary symptoms. Much information is now available on the respiratory changes resulting from insecticidal action on various metabolic processes as determined from tissue brei studies. Reference to these will be made later in this paper. The tracheae of poisoned insects show very few pathological symp- toms. In some cases the spiracles may remain open during the course of poisoning, but it has been established that very little or no increase in evaporation from the insect results (34). Digestive System The digestive system usually shows very little gross change after the ingestion of most insecticides ; in some cases there may be a definite colour change in the midgut. Practically all histopathological studies have been done on the midgut since no apparent changes have been noted in either the oesophagus or the hindgut. Pathological changes which may occur in the midgut vary from complete defoliation and destruction of the epithelium to no apparent effect on the cells, depending on the insecticide and the insect. Complete destruction of the midgut epithelium occurs in most insects during the course of poisoning with fluorides, arsenates, and arsenities (22, 27, 39). It is considered that these insecticides cause the precipitation of proteins in the midgut cells with the resultant destruction of the cellular protoplasm. The epithelial cells of the midgut of bees poisoned by the ingestion of DDT showed increased proliferation, vacuo- lization, and secretion, as though the hyperactivity of the insect was also causing increased metabolic activity in these cells; an organophosphorous compound, parathion, had no apparent effect on the midgut (26). Muscles It is obvious that the muscles of insects poisoned by “nerve poisons’”’ must be affected in some way since hyperactivity, tetanus, and paralysis are among the pathological symptoms. Lesions have been noted in the muscles of insects poisoned with arsenicals, pyrethrins, and DDT (16). These include fenestration of the cytoplasm, clumping of the nuclear chromatin, accentuation of the nodes and of Krause’s membrane, loss of striation, and the destruction of the nuclear membrane. These lesions are probably not caused directly by the poison; they are more likely to be the manifestation of abnormal metabolic conditions in the muscle resulting from increased nervous activity. Nervous System The nervous system has probably received more attention from path- ologists than any other system because of its important role in the physio- logical well-being of the insect and because many of the symptoms dis- played by poisoned insects appear to originate from it. Histopathological changes which occur in the nervous tissue of poisoned insects have been variously interpreted. Moreover, doubt has been cast on the validity of much of the early work on nerve pathology since it is considered that the conditions described were the result of post-mortem changes (25). Lesions 29 have been described in the brain, ganglia, and connectives in insects poisoned with pyrethrins, DDT, and several other insecticides (15, 16). The principal changes were abnormal staining reactions indicating chemi- cal changes in the cells, dissolution of the nerve fibers and other cellular components, and vacuolization of the larger nerve cells. These lesions are unlikely to be the primary cause of death; they are probably evidence of metabolic derangement in the cells of the nervous system. EFFECTS OF PHYSICAL POISONING These “poisons” are considered to be those which can inflict an injury on an insect by physical, rather than chemical means. Certain non-volatile oils may block the tracheae and the affected insect is believed to die of suffocation. Pathological conditions typical of anoxia, such as the clumping of the nuclear chromatin around the nucleolus leaving the rest of the nucleus filled with a clear liquid and a reticulate arrangement of the Nissl granules, have been observed in these insects (24). However, lack of oxygen may only be an indirect cause of death since the oil may be trapping toxic metabolites within the insect (29), or may even have a direct chemical effect on the cells. Such action is known to occur with the more volatile oils (24). Late-instar nymphs of Dysdercus sp. treated with some inert dusts showed simple abrasion of the epicuticle (36). Death was considered to be the result of desiccation resulting from the disruption of the water- proofing layer in the epicuticle. The subject of desiccating dusts and oils has been rather thoroughly discussed by Ebling and Wagner (11) who have noted that fatal desiccation can also occur with the removal or dis- ruption of the waterproofing wax layer by adsorption with a wide variety of dusts and silica aerogels. Refined petroleum oil can also dissolve or permeate the lipoid film on the surface of the cuticle and draw water from the insect (35). The efficiency of this action is increased when a surface- active agent is added to the oil to decrease the tension at the oil-water interface (12). RECENT DEVELOPMENTS In the last few years, the emphasis in pathological research relative to insecticide poisoning has tended more and more towards the study of the functional rather than the structural changes that occur in a poisoned insect, A prerequisite to these studies, and especially to the interpretation of the results, is a knowledge of physiological and biochemical functions in normal insects. Insect physiologists have borrowed heavily from the knowledge and techniques of vertebrate and mammalian physiologists. But, since the physiology of an insect differs in many ways from that of a vertebrate, caution must be used in interpreting the results. The situation is further complicated because the physiology of one species of insect may differ from that of another and may also vary between different develop- mental stages in the same insect. Unfortunately, many of the biological processes in insects are only partially understood. In recent years an understanding of the basic physiological and bio- chemical processes of the nervous system in insects has been obtained by studying the effects of drugs and insecticides in isolated heart, nerve, and nerve-muscle preparations (10, 14, 20, 33). Pathological conditions revealed as variations in the electrical impulses which occur during nerve action have been measured with various types of apparatus. Since the properties and physiological actions of the drugs used are known, at least in vertebrates, a comparison of the data obtained from drug-treated preparations with those obtained from the insecticide-treated preparations 30 has provided much basic knowledge of the nervous mechanisms and of how insecticides affect them. It is generally agreed that nervous activity in insects is mediated by a cholinergic system somewhat similar to that found in vertebrates. Many workers have found that acetylcholinesterase, an important enzyme in this cholinergic system, is inhibited by organophos- phorous insecticides. This inhibition causes a disturbance in the metabolism of acetylcholine (2, 28). Although the neurophysiological significance of these effects is still in doubt, the inhibition of acetylcholinesterase probably accounts for both the hyperactivity and subsequent paralysis in the poisoned insect. There is no doubt that this inhibition is the major bio- chemical event in organophosphorous-poisoned insects but there is evidence to indicate that it may not be the only one, since these compounds can inhibit other esterases (30, 3, 6). These aliesterases have been connected with the biochemical mechanism responsible for organophosphate resistance in house flies (5). Although resistant flies contain less aliesterase than susceptible flies the enzyme in resistant flies has the capacity to degrade organophosphates (6). High aliesterase inhibition and low cholinesterase inhibition have been found to occur in the house fly at the time of knock- down by organophosphates (4). Since nothing is known about the normal function of the aliesterase, any theory that ascribes the toxic action of organophosphates to aliesterase inhibition must be speculative (4). Considerable evidence has accumulated that oxidative metabolism in insects is directly affected by DDT, but this is not considered to be a primary factor in the lethal action of the poison. Nervous tissue is un- stabilized in some way by DDT, but whether this is effected by direct physical action on the nerve membrane or by a biochemical mechanism is not known (37). Time does not allow a continued discussion of all the biochemical abnormalities that have been found in insecticide-treated insects. Of necessity, most determinations of metabolic variations during insect poisoning have been done on homogenized whole insects or certain tissues of the insect that had been poisoned in one way or another. There are several objections to the use of tissue homogenates in enzyme inhibition studies. For example, evidence of enzyme inhibition may not be final since it is obtained from material in which the enzymes have been torn out of their normal position within the cell. There is no guarantee that these enzymes will have the same characteristics as they had in the intact cell, nor is there any guarantee that the enzymes affected by a poison in a tissue homogenate are the same ones that would be affected if the cells of the insect were intact. Probably one of the most serious deficiencies is the lack of specificity of enzyme location — which organ, which cells in an organ, and which parts of the cells produce the enzyme inhibited? Microscopic techniques are now available for determining the distribution of particular chemical constituents in cells or parts of cells. These methods are still, unfortunately, essentially qualitative rather than quantitative but they permit a degree of localization much greater than qualitative chemical techniques. The cellular localization of several enzymes, among them cholinesterase and acetylcholinesterase, is now possible histochemi- eally (13): The first application of histochemical techniques in the determination of enzymatic-inhibition in insects was on the organophosphate-poisoned egg of Pieris brassicae L. (23). Preliminary experiments indicated that the cholinesterases of the neuropile in the ventral nerve cords of the almost fully developed embryo were being inhibited. Connell (11) showed that the inhibition of acetylcholinesterase by TEPP and malathion in the ol adult house fly brain was localized in particular areas and traced the progress of inhibition from one area to another. Winton et al (38) demon- strated the presence of an enzyme that hydrolyzed acetyl thiocholine and which was inhibited by para-oxon and TEPP in the exposed neural fibre areas of the ventral nerve cord of the cockroach; acetyl thiocholine did not penetrate the intact nerve sheath and its action in the ganglia was not. determined. Using phenyl] thioacetate, a substance that does penetrate the nerve sheath, as substrate, they were able to show cholinesterase localized along the surface of the neurons and in the ganglia beneath the nerve sheath; the material of the neuropile showed no activity. Pretreat- ment of the insects with TEPP and para-oxon inhibited the enzyme in neuron connectives but left a slight positive activity in the ganglia. At the present time, attempts are being made in some laboratories to adapt histochemical methods for electron microscopy and thus localize in greater detail the sites of enzymatic activity within the cell. The effect of in- secticides on other enzymes in situ has not been studied as yet, but this approach to the problem of determining the site of action of an insecticide has great promise. Autoradiographic techniques, with which the distribu- tion of a radioactively labelled insecticide or its metabolites can be traced to restricted areas and even to definite cells within the insect, should also be applied to this problem. It has been suggested that some insecticides may act in several ways at once and that death of the insect is the result of the summation of the resulting biochemical and physiological abnormalities rather than the result of a single lesion (37). Certainly all the data so far obtained con- cerning the effect of insecticides on insects indicates that several parts or systems of the insect are affected in some way before death becomes inevitable. However, before this question can be answered we must be able to pinpoint the intial site of action of the poison and follow the progress of poisoning until the insect is fatally injured. To do this will require the cooperative efforts of many disciplines.. LITERATURE CITED (1) ARNOLD, J. W. (1952). Effects of certain fumigants on haemocytes of the Mediterranean flour moth, E'phestia ktuhniella. (Lepidoptera: Pyralididae). Canad. J. Zool. 30: 365. (2) ASPEREN, K. van (1958). Mode of action of organophosphorus in- secticides. Nature 1/81: 355. (3) ASPEREN, K. van. (1959). Distribution and substrate specificity of esterases in the housefly, Musca domestica L. J. ins. Physiol. 3: 306. (4) ASPEREN, K. van. (1960). Toxic action of organophosphorus com- pounds and esterase inhibition in houseflies. Biochem. Pharmacol. FOO. (5) ASPEREN, K. van. and OPPENOORTH, F. J. (1959). Organophosphate resistance and esterase activity in houseflies. Ent. exp. and appl. 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Ph.D. thesis, University of Western Ontario, London, Canada. (Unpublished). EBELING, W. and WAGNER, R. E. (1959). Rapid desiccation of dry- wood termites with inert sorptive dusts and other substances. J. econ. Ent. 52: 190. GEREBTZOFF, M. A. (1959). Cholinesterases. A histochemical con- tribution to the solution of some functional problems. Pergamon Press, New York, N.Y. HARLOW, P. A. (1958). The action of drugs on the nervous system of the locust (Locusta migratoria). Ann. appl. Biol. 46: 55, HARTZELL, A. and ScuDDER, H. I. (1942). Histological effects of pyrethrum and an activator on the central nervous system of the housefly. J. econ, Ent. 35: 428. HARTZELL, A. (1945). Histological effects of certain sprays and activators on the nerves and muscles of the housefly. Contrib. Boyce Thompson Inst. 1/3: 443. HARVEY, G. T. and Brown, A. W. A. (1951). The effect of insecti- cides on the rate of oxygen consumption in Blattella. Canad. J. Zool. eo AD, JONES, J. C. (1957). DDT and the hemocyte picture of the meal- worm, Tenebrio molitor L. J. Cell and Comp. Physiol. 50: 4238. Lorp, K. A. (1950). The effects of insecticides on respiration. II. The effects of a number of insecticides on the oxygen uptake of adult Triboliium castaneum Hbst. at 25° C. Ann. appl. Biol. 37: 105. NAIDU, M. B. (1955). Physiological action of drugs and insecticides on insects. Bull. ent. Res. 46: 205. OSER, W. B. and Brown, A. W. A. (1951). The effect of insecticides on the heart-beat of Periplaneta. Canad. J. Zool. 29: 54. PILAT, M. (1935). Histological researches into the action of insecti- cides on the intestinal tube of insects. Bull. ent. Res. 26: 165. POTTER, C. and MoLuoy, F. (1958). Report Rothamsted Expt. Sta. for 1957; p. 131, RICHARDS, A. G. (1941). Toxic and suffocating effects of oils: Culex. Trans. Amer. Ent. Soc. 67: 161. RICHARDS, A. G. and CuTKomp, L. K. (1945). Neuropathology in msects. J: N.Y. Ent. Soc. 53: 313 SALKELD, E. H. (1950). Changes in the histology of the honey-bee ventriculus associated with the ingestion of certain insecticides. Nature 116: 608. SALKELD, EF. H. (1951). A toxicological and histophysiological study of certain new insecticides as ‘‘stomach poisons” to the honey bee : Apis mellifera L. Canad. Ent. 83: 39 and 53. Do (28) SMALLMAN, B. N. and FISHER, R. W. (1958). The effect of acetyl- cholinesterases on acetylcholine levels in insects. Proc. 10th Int. Conner; bint: 25 5. — (29) SMITH, E. H. and PEARCE, G. W. (1948). The mode of action of petroleum oils as ovicides, J. econ. Ent. 41: 173. (30) SPENCER, E. Y. and 0’BRIEN, R. D. (1957). Chemistry and mode of action of organophosphorus insecticides. Ann. Rev. Ent. 2: 261. (31) STEINHAUS, E. A. (1949). Principles of Insect Pathology. MeGraw- Hill Book Co., Inc., New York, N.Y (32) STERNBURG, J., CHANG, S. C. and KEARNS, C. W. (1959). The release of a neuroactive agent by the American cockroach after exposure to DDT or electrical stimulation. J. Econ. Ent. 52: 1070. (83) Twaroc, B. M. and RoEDER, K. D. (1957). Pharmacological observa- tions on the desheathed last abdominal ganglion of the cockroach. Ann. Ent. Soc. Amer. 50: 231. (34) WIGGLESWORTH, V. B. (1941). The effect of pyrethrum on the Sspiracular mechanism of insects. Proc. R. Ent. Soc. Lond. A J6; 11. (85) WIGGLESWORTH, V. B. (1942). Some notes on the integument of insects in relation to the entry of contact insecticides. Bull. ent. Res. 93: 205" (37) WINTERINGHAM, F. P. W. and LEWIS, S. E. (1959). On the mode of action of insecticides. Ann. Rev. Ent. 4: 303. (88) WINTON, M. Y., METCALF, R. L. and FUKUTO, T. R. (1958). The use of acetyl thiochloine in the histochemical study of the action of organophosphorus insecticides. Ann. Ent. Soc. Amer. 5/1: 436. (89) WokKE, P. A. (1940). Effects of some ingested insecticides on the midgut wall of the southern armyworm larva. J. Agric. Res. 6/: 321. (Accepted for publication: January 20, 1961) O THE EFFECT OF CHEMICAL CONTROL OF INSECTS ON WILDLIFE CONSERVATION’ INTRODUCTION C. C. STEWARD’ As part of the program of the annual meeting of the Society, a panel discussion on “The effect of chemical control of insects on wildlife con- servation’? was held in the amphitheatre of the New Biology building of the Ontario Agricultural College on November 24th, 1960, under the chairmanship of Dr. W. E. Heming, Ontario Agricultural College. The discussion was opened by the moderator, Dr. W. T. Oliver, Ontario Veterinary College, who pointed out the growing importance of the sub- ject and the urgency of greater understanding and co-operation between those responsible for the protection of wildlife and those who were inter- ested in the use and development of pesticides. 1A panel discussion presented at the 97th annual meeting of the Entomological Society of Ontario, Guelph, Ontario, November 23-24, 1960. 2Entomology Laboratory, Research Branch, Canada Department of Agriculture, Guelph, Ontario. o4 The panelists discussed pesticides, bees, fish, food chains and wild- life. The papers presented showed that there was a large measure of agree- ment between the panelists on the status of pesticides in agriculture. It was admitted by all that pesticides may be hazardous when abused, but when prudently used are valuable adjuncts to conservation and production. The panelists stressed the need for co-operation and a sense of professional responsibility in the interpretation of short and long term effects, and regretted the degree of sensationalism recently given to the pesticide hazard. Reference was made to the care taken by the federal authorities to protect the consumer. It was generally agreed that there was a need for further research in pesticides and consideration was given to the support, methodology and nature of such investigations. Summaries of the papers, in the order in which they were presented, are given below. Dr. A. W. A. Brown’s contribution, which in many ways is a review of the whole subject, is given in full. O INSECTICIDE APPLICATIONS AND THEIR EFFECT ON WILDLIFE’ A. DE Vos’ The significance of the effects of pesticides on wildlife is not yet fully understood, but it is apparent that the problem is far from simple. Sometimes after intensive studies of one pesticide it may be found that new agents have been developed and studies must start all over again. Higher forms of life are most resistant to pesticides. Fish have died after applications of 0.25 lbs./acre of DDT in oil, whereas other cold-blooded vertebrates have tolerated amounts up to 1 lb./acre. Birds have tolerated up to 2 lbs./acre and mammals up to 5 lbs./acre, with little or no apparent immediate effect. However, most of the newer insecticides are more toxic to vertebrate life than is DDT. The effect of insecticides on field populations of higher animals may be direct or indirect. A few examples are given. In the field of forest insect control, applications during one season of 1 lb./acre of DDT are hazardous to tree-top inhabiting birds. When a single dosage is increased to 3 lbs./acre there is no observable effect on adult birds, but there is considerable increase in mortality among nestlings. Numerous reports indicate that wildlife mortality has occurred as a result of treatments for Dutch Elm disease control. Dosages are usually from one to 5 lbs./acre per tree. In sprayed communities in Wisconsin, song birds were reduced by 31% to 90%. There were 50 times as many robins in the average unsprayed community as in the most heavily treated community. The use of heptachlor and dieldrin for the control of fire ants shows severe mortality of birds following treatment of agricultural land in the U.S.A. There is serious reduction of ground-feeders but little effect on the higher-strata or tree-top species. Chemical tests of birds and mammals found dead revealed significant amounts of insecticide in their tissues. 1Summary of a paper presented at the 97th annual meeting of the Entomological Society of Ontario, Guelph, Ontario, November 23-24 1960, as part of a panel discussion on the effect of chemical control of insects on wildlife conservation. 2Department of Zoology, Ontario Agricultural College, Guelph, Ontario. 39 Other investigations show serious reduction of birds in orchards treated with DDT at 6 lbs./acre and of insectivorous species of birds where range land has been treated with heptachlor (0.125 to 0.25 lbs./acre), chlordane (0.5 to 1 Ib./acre), and toxaphene (1 to 1.5 lbs./acre) to contral grasshoppers and Mormon crickets. Indirect results of insecticides may also become apparent after con- siderable time. These indirect results may be increased mortality or loss of reproductive potential resulting from consumption of poisonous chemi- cals over a period of time. In laboratory studies some compounds are found to be additive and others synergistic. Some food organisms, such as earth- worms, are relatively resistant and may store toxicants. The following suggestions are made to reduce damage to wildlife: 1. Before insecticides are used, the effects on different kinds of animals and on animals living in different habitats should be studied in the area to be treated. 2. Only minimum quantities of chemicals and a minimum number of applications necessary to achieve adequate control of pests should be applied. ) 3. Whenever possible, chemicals should be applied at seasons when damage to wildlife will be least. 4, Particular caution should be taken with the applications of the highly toxic chlorinated hydrocarbons. 5. The minimum possible area should be treated. Serious effects are more likely to result from treatments over large areas. 6. Tightening up of federal and provincial legislation covering usage of insecticides should be recommended. The public needs protection from over-zealous or irresponsible control groups. 7. For the future, research should be pressed in two directions: (1) development of more specific chemicals and more specific methods of application; (2) development of biological and environmental controls. Entomologists and wildlife biologists in the United States and Europe are quite ready to acknowledge that insufficient research work has been done there regarding the effects of insecticides on wildlife, but at least they are doing something. In Canada no satisfactory research is in pro- gress at the moment and no special funds are available for this type of research. This is an undesirable situation. We should not rely on the find- ings of other countries, because of the different species of animals, habitats and climatic conditions with which we are concerned. We cannot afford to fall behind any further on this matter and I therefore wish to make a strong plea for funds to be made available to study the relationships between insecticides and wildlife and for the appointment of specialists on the subject either by institutes of higher learning or by the government. I also wish to suggest the enactment of legislation that prohibits improper or excessive use of toxicants that may injure wildlife. Legislation, similar to the Magnuson-Metcalf bill which was passed by the U.S. Congress in 1958, should be suggested to institute continuing studies of the effects of pesticides on wildlife. a6 THE EFFECT OF CHEMICAL CONTROL OF INSECTS ON BEEKEEPING' M. V. SMITH’ Losses caused by insects to agricultural crops in Canada run into hundreds of millions of dollars a year, but it should be pointed out that not all insects are injurious. The beekeeper relies on an insect for his livelihood and is justified if he views with alarm the increasing use of toxic chemicals on growing crops. Prior to 1939 there were scarcely more than a dozen pesticides in common use, but today more than 300 are listed in handbooks of agricul- tural chemicals. In 1954 one acre in five of agricultural crops in Canada was Subjected to some form of pest control treatment — a total of over 12 million acres. Research in California has shown that some 26 pesticides are highly toxic, and 15 more are moderately toxic, to honeybees; many of these are widely used for insect control. Honey bees may pick up poisons in any of the following ways: 1. Direct contact with sprays or dusts during application. 2. Contact with the blossoms or foliage of treated crops. 8. Contact with the blossoms or foliage of cover crops in orchards, or blooming crops bordering treated fields which may have been con- taminated with draft. 4. Consumption of contaminated nectar or pollen. 5. Consumption of contaminated water from foliage or pools, 6. Contamination of the hive entrance. Honeybee losses may occur: 1. In the field, when quick-acting poisons will wipe out most of the foraging population. 2. At the hive entrance, when contaminated bees return to the hive and crawl out to die. 3. Within the hive, when young bees or brood consume contaminated pollen or nectar which has been stored in the hive. 4. Brood mortality — other than poisoning — may occur when too few adult bees are left to care for the brood. The evaluation of honeybee losses from insecticides is difficult, except when the colony is killed outright. Other phases of agriculture may also be affected by honeybee poisoning. Thus a fruit orchard may produce a greatly reduced crop if a careless spray kills off the foraging bees. Some of the newer short residue insecticides are extremely toxic and have played havoc with honeybees in California this year. Various methods have been tried to confine bees to their hives until the poisoning danger is past; to date the only promising practice seems to be the use of black polyethylene plastic tarpaulins to cover whole groups of colonies. iSummary of a paper presented at the 97th annual meeting of the Entomological Society of Ontario, Guelph, Ontario, November 23-24, 1960, as part of a panel discussion on the effect of chemical control of insects on wildlife conservation. 2Department of Apiculture, Ontario Agricultural College, Guelph, Ontario. Proc, ent. Soc. Ont. 91 (1960) 1961 oT Points for further consideration: What the beekeeper can do: 1. Do not keep bees permanently in areas such as orchards where re- peated application of chemicals is carried out during the season. 2. Remove or confine bees during times of acute hazard. 3. Charge more for pollination services when there is a risk of poisoning. What the grower can do: Avoid using poison on open blossoms. Treat crops in morning or evening when bees are not active. Choose if possible a material that is not highly toxic to bees. Do not carelessly spill poisons where they may constitute a hazard to bees by contaminating water supplies. 5. ree to avoid drift onto adjacent crops, particularly if they are in bloom, 6. Notify beekeeper when poison is to be applied. Pea stale What the researcher can do: 1. Develop more specific toxicants. 2. When possible, make greater use of bacterial and virus agents for control of specific pests. 3. Develop biological control by means of parasites. 4. Pay more attention to ecological aspects in order to avoid killing beneficial parasites and pollinators. 5. Develop and test effective repellents to keep honeybees away from treated crops until the danger of poisoning is past. ————0 PROFESSIONAL RESPONSIBILITY’ H. HURTIG’ In recent years well intentioned but only partially informed scientists and laymen have become alarmed about possible hazards that pesticides may represent to man, animals, fish and wildlife. Many of these people or groups have been uncritically vehement in their attacks on pesticide use, resulting in inflammatory public statements and writings of questionable factual content. On the other hand, there is a temptation for agricultural production agencies working at the technology level of pest control to consider the resulting poor public relations as a threat to the performance of their duties, so they enter the controversy in public, with statements as questionable as those of their critics. Modern pesticides are valuable tools in plant and animal production, forest conservation and wildlife management. Professionally we should be just as concerned about correcting abuse of these valuable tools as we isummary of a paper presented at the 97th annual meeting of the Entomological Society of Ontario, Guelph, Ontario, November 23-24, 1960, as part of a panel discussion on the effect of chemical control of insects on wildlife conservation. 2Program Directorate, Research Branch, Canada Department of Agriculture Ottawa. Proc. ent. Soc. Ont. 91 (1960) 1961 38 are about their proper use. I submit that an entomologist’s professional and moral responsibility does not end, nor is research complete if pro- fessional advice is restricted to time, rate and dose of pesticide applied to obtain a desired level of pest control. No pest control recommendation can be considered complete today unless pertinent accompanying informa- tion is provided on economy and safety of use, as well as efficiency. It is easy to be sophisticated and critical with hindsight, but it requires professional honesty and responsibility to constantly review current pest control recommendations in the light of new scientific in- formation and revise them accordingly. The same type of objective ap- praisal of hazard, with an unbiased scientific approach and professional dignity is required from wildlife biologists interested in correcting abuses. There are needs for collaborative research, these should be pointed out by submission of findings, first of all to fellow scientists rather than to the sensation seeking press. The establishment in 1958 of the Inter- departmental Committee on Forest Spraying operations and the program of work resulting from this approach exemplifies what can be done through scientific channels. The average entomologist or wildlife specialist in Canada today, has neither the training, background or interest to cope with the expanding needs for research on the various facets of pesticide use, or interpret pertinent literature for advisory purposes. A new type of specialist is required and many career opportunities are open. Canadian universities are not yet producing graduates with the background and training re- quired for basic and applied research in this field. * ee EFFECTS OF FOREST SPRAYING WITH DDT ON AQUATIC INSECTS, FOOD OF SALMON AND TROUT, IN NEW BRUNSWICK’ F. P. IDE’ Extensive forest spraying has been carried out in New Brunswick by Forest Protection Limited since 1952. The standard spray has been DDT in oil delivered from aircraft at the rate of one half-pound of DDT per acre. The area sprayed has varied from year to year with severity of the attack of spruce budworm, the greatest area, 5,500,000 acres being treated in 1957. Since 1954 the Fisheries Research Board of Canada has followed the operation from the standpoint of its effect on the salmon in the streams, Part of this program has been an investigation of the effect the spraying has on the life in the streams, particularly the aquatic insects, which form the most important component of the food of the young salmon and trout. The present contribution deals with this aspect of the spraying. Trapping the emerging insects from yard-square areas of rapids over a twenty-four hour period, five days a week from early to late summer has given comparative data for sprayed and unsprayed streams. iSummary of a paper presented at the 97th annual meeting of the Entomological Society of Ontario, Guelph, Ontario, November 23-24, 1960, as part of a panel discussion on the effect of chemical control of insects on wildlife conservation. 2Department of Zoology, University of Toronto, Toronto, Ontario. Proc. ent. Soc. Ont. 91 (1960) 1961 a9 The fauna of Trout Brook, a relatively small tributary of the North- west Miramichi River, sampled 1955-60 and sprayed in 1956, was radically — altered by the spraying, mainly apparent in the extreme reduction in the larger insects — mayflies, stoneflies and caddisflies — and an increase in the small midges, as compared with their numbers in the pre-spray year. By 1960 this stream’s fauna had apparently recovered qualitatively, as the number of kinds of mayflies, stoneflies and caddisflies had come back in the samples until they were comparable to those of the pre-spray fauna. The numbers of midges, however, remained disproportionately high, and the total bulk of insects in the samples was lower than in pre-spray samples. | Larger streams, the North Branch of the Big Sevogle and the Northwest Miramichi Rivers, were more seriously affected in some sec- tions than was the Trout Brook. These streams, tributaries of the main river and in the same general area, were first sprayed in 1954. The Sevogle was sampled 1955-56-57 and the Northwest Miramichi 1957-60 and compared with an unsprayed control stream of similar character in the area, Millstream Brook, a tributary of the Northwest Miramichi River, sampled 1955-59. Recovery in these was slower than in the Trout Brook. The fauna of the Northwest Miramichi, not sprayed after 1954, was comparable to that of the control stream for number of kinds of mayflies and stoneflies in the 1960 sampling, but the number of kinds of caddisflies emerging in 1960 was only approximately half the number in the control. The fauna of the small stream therefore has apparently taken four years to recover and that of the larger has not completely re- covered in six years, It has been assumed the fauna of the larger streams including the control stream was rather similar under pre-spray condi- tions since they are tributaries of the same river in similar terrain. O THE EFFECT OF THE CHEMICAL CONTROL OF INSECTS ON WILDLIFE CONSERVATION: EVALUATION OF THE PRESENT IN THE LIGHT OF PAST EXPERIENCE’ A. W. A. BROWN’ The modern powerful insecticides, along with aircraft and other new application equipment, offer a new tool to the hand of those who wish to conserve their resources for one purpose or another, if only to save them from the insects. The control of a spruce budworm outbreak is an act of conservation which avoids a fire hazard, while area operations against the gipsy moth or tent caterpillar are aimed at conserving the forest for humans and one presumes for wildlife. Mosquito and black-fly control allows what is conserved to be enjoyed. Even elm bark-beetle control is aimed at conserving shade trees and nesting sites against destruction by the Dutch elm disease. Modern insecticides have made all these measures possible, besides the increasingly efficient protection of crops and elimina- tion of insect vectors of disease. 1Presented as part. of a panel discussion on the effect of the chemical control of insects on wildlife conservation at the 97th annual meeting of the Entomological Society of Ontario, Guelph, Ontario, November 23-24, 1960. 2Department of Zoology, University of Western Ontario, London, Ontario. Proc. ent. Soc. Ont. 91 (1960) 1961 40 These insecticides are biologically active chemicals which have been chosen and developed because they have maximum effect on insects and minimum effect on vertebrates. Thus there is a factor of safety separating the dosage that eliminates the insects and the higher dosage at which serious consequences to higher animals develop. Initial laboratory assess- ments, small-plot tests, large-scale experiments and finally practical use of any agricultural chemical are concerned with establishing and verifying these two dosages (6). If they enclose a factor of safety that is too narrow, that insecticide should be discontinued or replaced. The most generally useful insecticide is DDT; indeed it is the material of choice in all the control operations already mentioned. When we con- sider the effect of DDT in wildlife conservation, we think first of birds. Extensive field experiments have shown that no material damage to birds results from DDT dosages of 2 lbs./acre or less (30), and this has been officially stated by the U.S. Fish and Wildlife Service (32). The dosage employed for gipsy moth eradication is 1 lb./acre, and the DDT level used for spruce budworm control was reduced several years ago from 1 lb./acre to 0.5 Ibs./acre. No significant decrease in bird population has been noted over these control and eradication areas (4, 21, 37), which have recently amounted to more than 2 million acres annually. Closely-observed experi- ments in Algonquin Park, Northwestern Ontario and Maryland had already shown that DDT at.1 lb./acre did not reduce the bird population, nor cause any detectable loss in the reproductive success(19). Repeated applications of this dosage during the one season are hazardous; for example, an area sprayed 4 times at 1 lb./acre for gipsy moth control suffered a loss of one-third of the population of tree-top species (30). When the single dosage is increased to 3 lbs./acre, although there is no observable effect on adult birds, there is considerable mortality among nestlings (24). DDT is widely applied in orchards against the codling moth, although its use is now being reduced by the onset of DDT-resistance, by its failure to control the red-banded leaf-roller, and by its promotion of red-mite outbreaks. The dosage rate is approximately equivalent to 6 lbs./acre, and must make the orchard less habitable for birds. In the extensive orchards of British Columbia, there is resultant mortality among pheasants, al- though the population as a whole survives (27). This DDT dosage leaves deposits on the cover vegetation of about 500 p.p.m. The experimental contamination of breeding-season diets with DDT at 100 p.p.m. has been found to reduce the egg production of pheasant, while 200 p.p.m. in the reproductive diet of bobwhite quail so weakens their brood that the natural chick mortality is increased to 98 per cent (7). This penumbra of DDT effects on the reproductive rate, known for many years in laboratory rats, has yet to be quantitatively assessed in the field. : Dutch elm disease control by spraying these shade-trees against the bark-beetle involves similar dosage rates. The minimal DDT dosage is about 1 lb. per tree, giving a deposit of 1 lb./acre on the ground at time of spraying and of 5 lb./acre when the sprayed leaves have fallen (2). It is however preferable to spray during the dormant season in March, using mist-blowers rather than hydraulic sprayers in order to ensure maxi- mum economy in deposition and avoid producing hazardous pools of run- off. Unfortunately elm bark-beetle control has a bad record of killing American robins; the casualty list also includes starlings and grackles in the mid-west and myrtle warblers in the East, although the migrant Species are generally not affected. In Wisconsin towns sprayed annually for 3 years at 1-2 lb./tree the general bird population has been found to be 10-70 per cent of the normal level, and the robin population to be only Al 2-30 per cent of that in an unsprayed town (16). Dormant sprays also at 2-5 lb./tree caused sufficient casualties in the succeeding 2 weeks to raise ae seasonal mortality rate from its normal 50% up to 80-90 per cent (15). DDT does not kill birds by direct contact; nests containing young have been sprayed at 5 lbs./acre and no effect was observed (23). The mortality is due to (a) the reduction in the supply of insects as food, and (b) the uptake of DDT in the surviving invertebrates still available as food (9). It has been found that earthworms under trees sprayed at 1 lb./tree contain in the following spring enough DDT in their guts to constitute a lethal dose for a robin with an appetite for a hundred worms (2). A similar food-chain hazard was also responsible for mortality of grebes in California that had fed on fish in Clear Lake that had been treated 4 times with the insecticide DDD for gnat control (26). The surviving populations of robins in the Wisconsin towns, among the trees saved from Dutch elm disease, were observed to complete their nesting and rear their young successfully (16), It would appear that the concealed long-range dangers are not serious beyond the further accumula- tion of DDT in the soil, and that we can count the cost of such operations fairly accurately. But the cost is large enough, not only to the birds them- selves, but also in the engendering of a fear of insecticides in the general public. We must therefore look for a substitute for DDT that lacks its persistence and food-chain toxicity. Methoxychlor has been remommended by the U.S. Forest Service, but it is considerably less effective against the bark-beetle (22). Systemic organophosphorus insecticides for tree- trunk injection have so far proved unsuccessful (1). Only lindane (the gamma isomer of BHC) is just as effective as DDT (8) and should be less hazardous for the bird populations, Meanwhile in forest spraying it appears that DDT at 1 lb./acre, or better 0.5 lb./acre, does not militate against the conservation of birdlife. Mosquito and black-fly control operations, employing 0.2 lb./acre or less, probably have no material effect on birds. Experimental air-spraying of open marshes with DDT at 0.2 lb./acre caused no detectable reduction in the population except for the discovery of one mangled corpse of a Virginia rail (13). The increasing rarity of the bald eagle on the U.S. Atlantic coat has yet to be causally connected with mosquito control operations (11). Of the other chlorinated hydrocarbon insecticides, those of the cyclo- diene group are considerably more hazardous for birds. Dieldrin at 0.2 lb./acre, applied as a mosquito larvicide in New Jersey, caused mortality among songbirds; at 0.5 lb./acre against rice stem borer in California, diel- drin killed considerable numbers of pheasants, doves and aquatic birds (27). Aldrin at 2 oz./acre, airsprayed for grasshopper control, killed duck- lings in North Dakota marshes and starved redwing blackbird nestlings to death on Montana uplands (27). Dieldrin, aldrin and endrin all have de- leterious effects on reproduction; only 10 p.p.m in the reproductive diet of pheasants reduces egg-hatch and chick survival, while 1 p.p.m in the diet of quail chicks induces a high mortality rate (7). Chlordane is less toxic to birds, and toxaphene still less toxic. Never- theless chlordane at 0.5 lb./acre in bran baits for grasshopper control has caused some loss in larks and gallinaceous birds on Wyoming rangeland (27). Heptachlor, also present in technical chlordane, is intermediate be- tween dieldrin and chlordane in toxicity. The imported fire ant, a recently- introduced pest, is being attacked for erdication with heptachlor at 2 lb./acre in granules (10). This campaign is of vital interest to farmers in 42 the southeastern U.S. whose fields are being made difficult to cultivate because of the ant mounds and unhealthy to enter because of ant stings. Unfortunately this treatment kills many birds of all species (3), and eliminates the breeding of quail and wild turkey populations (28) ; the mortality rate is highest in the spring (12). BHC and its gamma isomer formulation (i.e. lindane) are evidently less hazardous to birds even than DDT. Lindane at 0.2 lb./acre sprayed on New Jersey marshes caused no detectable effect (13) ; and in western Europe applications of BHC at 50 lb./acre (5 lb./acre gamma isomer) were found harmless to the bird population, except surely to make their food somewhat unpalatable (27). Of the organophosphorus insecticides now widely used in orchards and on crops, parathion, TEPP and malathion are the most common. Parathion in British Columbia orchards has caused slight losses of doves, quail and pheasants, although any songbirds remaining during the appli- cation are often killed. TEPP has been harder on the bird population because in its early years the sprays were often applied at night when the birds were roosting (27). Malathion is much safer and apparently causes no loss; applied at 0.6 lb./acre up to 8 times a year over 800,000 acres in Florida for eradication of Mediterranean fruit fly, it produced not a single confirmed case of bird mortality (4). The new carbamate insecticide Sevin, substituted for DDT for gipsy-moth control in dairy areas, is safe for birds at the 1.25 lb./acre employed (87) ; but it is death on bees and fails to eradicate the gipsy-moth, For mammalian wildlife, forest spraying with DDT at 1 lb./acre is without detectable effect ; mortality is not evident even in mice and shrews until the dosage exceeds 5 lbs./acre (4, 25). Lindane, chlordane and toxa- phene have the same general level of hazard to mammals, but aldrin and dieldrin are considerably more toxic. However, aldrin at the customary 0.2 lb./acre in grasshopper baits killed only mice and no larger animals. Dieldrin sprayed at 1 lb./acre in California orchards has killed rabbits, hares and even dogs, while endrin at 2.5 lbs./acre has been used as a rodenticide to kill mice in orchards. Parathion and TEPP are more hazardous to mammals than DDT, but malathion is virtually harmless (27). The fish population however does suffer when forests are sprayed with DDT at 1 lb./acre. In hardwood forests, where only a quarter of the dosage reaches woodland streams and pools, the fish mortality consequent on gipsy-moth operations is sporadic (37) ; only where airspray shut-off is tardy and open water is hit have fish been killed in the dozens (4). In coniferous forests, where canopy screening is less pronounced, spruce budworm control operations have involved considerable fish mortality in certain regions. A dosage of 1 lb./acre on the Yellowstone watershed caused a large kill of trout and bottom-feeders, which were starved for lack of their arthropod food. Applications of 0.5 lb./acre on the Miramichi watershed have produced kills of young salmon sometimes reaching 90% mortality, again due to starvation (20), although poisoning with DDT in water and food is also a factor (18). These complications in New Brunswick are receiving expert attention, and the feasibility of changing the dosage to 0.25 lb./acre is being investigated (34). With mosquito control operations, the usual DDT dosage of 0.2 Ibs./acre have been found on New Jersey marshes to involve negligible damage on the fish population, although a few dead fish may be found (13). The U.S. Fish and Wildlife Service has fixed 0.2 lb./acre as a safe dosage for DDT in mosquito larval control, provided it is applied only once in the season (31). The RCAF airsprays more than 100 sq. miles around 43 northern bases each year with DDT at 0.2 lb./acre, and has found no evidence of fish kill (86); this dosage is also used to protect pulpwood cutters against blackflies in northern Quebec (35). Where oil solutions are employed, it is best to have the DDT concentration as high as possible (e.g. 10%) to keep the oil slick as little as possible. In very shallow, warm and exposed waters mortality may result from DDT at 0.1 lb./acre (5); for this reason the U.S. Public Health Service favours 0.05 lb./acre where repeated DDT applications are used in malaria control. The direct treat- ment of streams with oil solutions to give a DDT dosage of 0.1 p.p.m/15 minutes for elimination of blackfly larvae has been found by conservation officers in New York state to have no direct effect on fish (17). Of the other chlorinated hydrocarbons used in mosquito control, gamma-BHC (lindane) is no more toxic to fish than DDT, and caused insignificant mortality at 0.1 lb./acre (13). Heptachlor is not appreciably more toxic, a dosage of 0.2 lb./acre involving slight mortality. Dieldrin is definitely more toxic, causing considerable kill at 0.1 lb./acre (29). However, such insecticides may be made safer for fish by using granules instead of oil solutions (31). Toxaphene is strongly toxic, and endrin more toxic still; streams draining cottonfields in the southeastern U.S. have been temporarily cleared of fish by these cotton insecticides being carried in the run-off water. The organophosphorus insecticides, used in increasing amounts due to resistance of mosquitoes and the cotton boll weevil to chlorinated hydro- carbons, are on the whole less toxic to fish than DDT. Parathion at the dosage of 0.1 lb./acre used in mosquito control is virtually safe for fish. Malathion at the usual dosage of 0.5 lb./acre has not involved problems of fish mortality, although it appears that some species such as bluegill sunfish and killfish are more susceptible to malathion than others (4, 27, 29). An even higher safety factor is offered by chlorthion and Dipterex, although again there is much interspecific variation in susceptibility (33). Besides these organophosphorus compounds, the safest mosquito larvicides for fish are DDD and Sevin (14). Here in Canada, the insecticide employed for application over large areas, whether against forest insects or biting flies, is DDT. At least 100 investigations have been made of its effect on fish and wildlife in various parts of the world and experience has accumulated for several million acres sprayed each year during the past 6 years. We can state now that the following dosages of DDT are safe, within reason: 5 lb./acre for mammals, 1 lb./acre for birds, and 0.2 lb./acre for fish. The importance of dosage levels cannot be too heavily stressed, especially in informing the public. Of the alternative insecticides, the cyclodiene compounds are con- siderably more hazardous to wildlife, and for safety should be applied in granules rather than sprays. The gamma isomer of BHC is no more hazardous than DDT, and certain organophosphorus compounds such as malathion are actually less hazardous. Where there is need for further study of the effects of DDT, it is in the field of census and reproductive rates to characterize more accurately its safety limits. With the scientific information we already possess and must continue to accumulate, the wonderful gifts of the synthetic chemists should take their rightful place as tools for conservation. LITERATURE CITED (1) AL-AzAwl, A. F. and CAsipA, J. E. (1958). The efficiency of sys- temic insecticides in the control of the smaller European elm bark beetle. J. econ. Ent. 57: 789-790. 44 (2) (3) (4) (9) (6) (7) i) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) BARKER, R. J. (1958). Notes on some ecological effects of DDT sprayed on elms. J. Wildlife Mgt. 22: 269-. BYRD, I. B. (1960). What are the side effects of the imported fire ant control program? Trans. Seminar on Biological Problems in Water Pollution, Tech. Rep. W60-3, Sanit. Eng’g. Centre, U.S. Pub. Health Service, Cincinnati 26. pp. 46-50. Copk, O. B. and SPRINGER, P. F, (1958). Mass control of insects: the effects on fish and wildlife. Bull. ent. Soc. Amer. 4: 52-56. COTTAM, C. and HIGGINS, E. (1946). DDT and its effect on fish and wildlife. J. econ. Ent. 39: 44-52. DECKER, G. C. (1960). Insecticides in the 20th century environment. AIBS Bulletin, April, pp. 27-31. DEWITT, J. B. (1956). Chronic toxicity to quail and pheasants of some chlorinated insecticides. J. Agr. Food Chem. 4: 863-866. DOANE, C. C, (1958). The residual toxicity of insecticides to Scolytus multistriatus. J. econ. Ent. 5/: 256-257. GEORGE, J. L. (1957). The Pesticide Problem. Conservation Founda- tion, 30 East 40th St., New York 16. Mimeo, 57 pp. GEORGE, J. L. (1958). The Program to Eradicate the Fire Ant. Conservation Foundation, 30 East 40th St., New York. Mimeo, 30 p.p. GEORGE, J.L. (1959) Effects on wildlife of pesticide treatments of water areas. Symposium on Coordination of Mosquito Control and Wildlife Management. April 1-2, Washington, D.C. GEORGE, J. L. (1960). Contribution to Panel on Implications of In- secticide Residues. 16th Ann. Mtg. Amer. Mosq. Contr. Assoc. Boston, March 30; unpublished. GEORGE, J. L., DARSIE, R. F. and SPRINGER, P. F. (1957). Effects on wildlife of aerial applications of Strobane, DDT and BHC to tidal marshes in Delaware. J. Wildlife Mgt. 21: 42-53. HENDERSON, C., PICKERING, Q. H. and TARZWELL, C. M. (1960). The toxicity of organic phosporus and chlorinated hydrocarbon insecti- cides to fish. Tech. Rep. W60-3, U.S. Pub. Hith. Series, pp. 76-88. HIcKEY, J. J. and HUNT, L. B. (1960). Initial songbird mortality following a Dutch elm disease control program. J. Wildlife Mgt. 24: 259-265. HUNT, L. B. (1960). Songbird breeding populations in DDT-sprayed Dutch elm disease communities. J. Wildlife Met. 24: 139-146, JAMNBACK, H. (1960). Statement made at 2nd Blackfly Conference, Queens Biol. Sta., L. Opinicon, Sept. 24. KEENLEYSIDE, M. H, A. (1959). Effects of spruce budworm control on salmon and other fishes in New Brunswick. Canad. Fish Culturist No. 24, pp. 1-6. See also: Canad. Audubon 21 (1): 1-7. KENDEIGH, S. C. (1947). Bird population studies in the coniferous forest biome during a spruce budworm outbreak. Dept. Lands and Forests, Ontario, Biol. Bull. No. 1. KERSWILL, C. J., ELSON, P. F., KEENLEYSIDE, M. H. A. and SPRAGUE, J.B. (1960). Effects on young salmon of forest spraying with DDT. Tech. Rep. W60-3, U.S. Pub. Hlth. Service. p. 71. See also: Atlantic Advocate 48 (8) : 65-68. (1958) ; Trade News (Dtp. Fish.) 9: 5-15; Fish. Res. Bd. Atlantic Prog. Repts. 62: 17-23, 45 (21) (22) (23) (24) (25) (26) (27) (28) (29) (30) (31) (32) (33) (34) (35) (36) (37) LEEDY, D. L. (1959). Pesticide-wildlife problems and research needs. Trans. 24th N. Amer. Wildlife Cont. pp. 150-165. Wildlife Manage- ment Institute, Wire Bldg., Washington, D.C. MATTHYSSE, J. G., MILLER, H. C. and THOMPSON, H. E. (1954). In- secticide deposits for control of elm bark beetles. J. Econ. Ent. #7: 739-746. ! MITCHELL, R. T. (1946). Effects of DDT spray on eggs and nestlings of birds. J. Wildlife Mgt. 10: 192-194. MITCHELL, R. T., BLAGBOROUGH, H. P. and VAN ETTEN, R. C. (1953). Effects of DDT upon survival and growth of nestling songbirds. J. Wildlife Met. 77: 45-54. | NELSON, A. L. and SURBER, FE. W. (1947). DDT investigations by the Fish and Wildlife Service in 1946. U.S. Fish Wildlife Serv., Spec. Sci. Rep. No. 41, 8 pp. Rupp, R. L. (1958). The indirect effect of chemicals in nature. Papers on Effects of Toxic Pesticides on Wildlife given at 54th Ann. Convent. Nat’] Audubon Soc., 1130 Fifth Ave., New York 28. Rupp, R. L. and GENELLY, R. E. (1956). Pesticides; their use and toxicity in relation to wildlife. Cal. Dept. Fish Game, Bull. No. 7, 209 pp. SPEAKE, D. W. (1958). Fire ant eradication and fire ants in Alabama. Papers on Effects of Toxic Pesticides on Wildlife given at 54th Ann. Convent, Nat’] Audubon Soc., 1130 Fifth Ave., New York 28. SPRINGER, P. F. (1956). Insecticides: boon or bane? Audubon Mag., May-June and July-August. SPRINGER, P. F. (1957). DDT: its effects on wildlife. Passenger Pigeon, Winter Issue. SPTINGER, P. F. (1958). Mosquito control and wildlife. Wildlife in North Carolina 22 (6): 3 pp. STICKEL, L. F. and SPRINGER, P. F. (1957). Pesticides and wildlife. U.S. Dept. Interior, Wildlife Leaflet 392, Mimeo, 12 pp. TARZWELL, C. M. (1958). The toxicity of some organic insecticides to fishes. Proc. 12th Ann, Conf. Southeastern Assoc. Game and Fish Commissioners, pp. 233-239 (Contrib. No. 116). WEsB, F. E. (1960). Aerial forest spraying against spruce budworm — a problem of mutual interest in Canada and the United States. J. Econ, Ent. 53: 631-633; se also: Tech. Rep. W60-3, U.S. Pub. Hlth. Service, pp. 65-70. WEsT, A. S. (1958). Biting Fly Control Manual. Woodlands Research Index No. 104, Pulp and Paper Res. Inst. of Canada, Montreal, 142 pp. WINMILL, A. E, and Brown, A. W. A. (1961). RCAF airspray for biting-fly control. Canadian Aeronautical Journal (in press). WoRRELL, A. C. (1960). Pests, pesticides and people. American Forests, July issue, 41 pp. Available from Conservation Foundation, 30 East 40th St., New York 16. (Accepted for publication: January 12, 1961) 46 ll. SUBMITTED PAPERS CONTROL OF CATERPILLARS ON LATE CABBAGE IN CENTRAL ONTARIO _ AND WESTERN QUEBEC, 1958-1959 L. M. CAss* In Ontario and western Quebec, late plantings of cabbage are attacked every year by caterpillars of three species, namely, the imported cabbage- worm, Pieris rapae (L.), the diamondback moth, Plutella maculipennis (Curt.), and the cabbage looper, Trichoplusia ni (Hbn.). The imported cabbage worm is the most important of the three species and causes con- siderable economic damage each year. The diamondback moth, although usually more numerous than the imported cabbageworm, is less important because it consumes less foliage per larva. The cabbage looper is not sufficiently abundant in most years to cause serious damage but was an important pest in 1957 and 1959. in t95o; DPT. for many years the insecticide recommended for control of caterpillars on cabbage in Ontario and Quebec, failed to give satisfactory control in the Ottawa Valley due to an outbreak of a strain of the cabbage looper resistant to it (2). Subsequent experiments at Ottawa (3) showed that endrin gave excellent control of all three species; however, because of the residue hazard, the material could be recommend only as a pre-heading application. In the same experiments, Phosdrin and Guthion were somewhat less effective but were of value for use after head formation. The preceding four materials were further appraised in 1958 and 1959 in comparison with a number of insecticidal dust combinations. METHODS AND MATERIALS The experimental plots were in growers’ fields, at Aylmer, Que., in 1958, and at Bradford, Ont., in 1959. The plots, which averaged one- fiftieth of an acre, were in four randomized blocks. The experimental areas measured 3/5 of an acre. The variety of cabbage in both years was Penn State Ballhead. Table I lists the insecticidal dusts and concentrations. They were applied with rotary hand dusters at average rates of 20 to 40 Ib. per acre of the diluted dust. Four applications were made at 15-day intervals be- ginning on July 22, 1958, and July 19, 1959. To reduce drift, the insec- ticides were applied in the early morning when wind velocities were low. Rainfall in the 48-hour period after each application was negligible. Population records To determine the relative abundance of Lepidoptera attacking the plants, larval counts were made in the untreated plots on four occasions each year. A leaf-by-leaf examination of 50 plants was carried out on each date, 13 of the sample plants being chosen at random from two of the four untreated plots, and 12 from the other two. The average numbers of larvae per plant were as follows: 1958 1959 Diamondback moth 2.2.2... 3.0 1.3 Imported cabbageworm ............. 1.9 4.3 Cabbage looper .... See Ycrit Guathiee 0.8 76 | As the feeding ratio of equal populations of the diamondback moth, the imported cabbageworm, and the cabbage looper is 1: 7.5 : 11.6 (4), 1Entomology Research Institute, Research Branch, Canada Department of Agriculture, Ottawa, Ontario. Proc. ent. Soc. Ont. 91 (1960) 1961 49 “8S6T Ul posn 4snp % %ex quo ‘al[tAyjeqdueg ‘peqruiy Auedwoy syonporg uintoyeD suryo ‘quQ ‘OJU0IOT, “py (epeueo) plelfso1p pue suosILaieyp ‘and ‘[eorjuoy “pz ‘epeueD FO ‘0D SUBITIIM-UIMISYS “UOISIAT(] SJONPOTd SSO1D U22I\)o ‘quo ‘T OJUOAOT, ‘epeueD Fo Auedwoy [IO [[9USq “6G6L ‘I 10q0790 pure ‘BcET ‘6% Tequioqideg “pozIUOjo[eYS SOABI] GLOW 10 DAT Ys cc a 2 ey, Te ee ee eee ee eee ee ee ee Sot Ly JPA] GT 7 | OT Rage > [PAV OAS 46 QOUBIIFIUSIS TOF peazmnbest VUILIT FTG ee Eh a ota me es ee ee eee ra ee oo SSS Beer oe coe 06 8IG <3ée ae Sea ce yooyO 98S VoL (peke satvlate) lt GGd «dus | 00 snd %& oLdd So7 S502 COS 996. LLY 896 G10 ysnqd %E — eloryyNny) e299 06 iY cab 86 V9E G2 Tt + 00°T ysnq %G + ysnq BP .ouvyjytog + wuomyzeley 669 19h 093 V2 FIG = 888 OOT+O00T NC HAS + Nd Vs peucydexoy, + «Lda GLL 888 L6ot TOtr HOS = Sake, OV'0 ind %T quitpsoud 68h 818 OS Vik 8838p = OV 0g°0 + 00°T jsnq %%s + Nd %G suoTyyny) -- Lad 808 c&6 ot) be a el) LVG 8L& Gc 0 ysnq %T qultpuy 696T 8961 6S6T 8961 696T 8961 ‘q[ ‘e108 ated UOTZB[NULLO eprorjoesuy JO1}UOD JuEeD 1eq 2% Oped , peururexe 1oquin Ny JUBOTXOL 9.d8}U9010g SLNVId HOVaEVO Cee een eee nee ee eee eee ee ee ee aay ncn MITT TEND uCD PU "6G6T “OlzeqUuQ “plofperg pue ‘eee, ‘Soqeny ‘Aow[Ay ‘Seprorjoosul SnolmeA Jo suoreordde «noF yyIM sseqqed oye] UO SIvl[id1eyeo JO [O1]UOD I WAV IL 50 the foliage consumptions (based on the product of the number of larvae and the feeding ratio) attributable to the three species were in the ratios of 1 :5 : 3 in 1958 and 1 : 32 : 24 in 1959. Consequently, the insecticides were evaluated essentially against the imported cabbageworm and the cabbage looper in both years. Criterion of effectiveness Effectiveness of the materials was based on caterpillar feeding injury to the plants at the beginning of harvest, September 29, 1958, and October 1, 1959. The injury records were taken independently by two observers and the results averaged. All the plants in each plot except those in the two outside buffer rows ard a three-foot buffer strip at the end of each row, were graded according to damage to the heads and leaves as follows: Grade 1, up to four leaves skeletonized; Grade 2, five or more leaves skeletonized. Grade 2 damage was sufficient to reduce or destroy the market value of the crop. A skeletonized leaf was one in which more than one-sixth of the leaf surface had been removed by feeding. Differences between treatments were assessed by the multiple range test of Tukey, as given in Federer (1). RESULTS AND DISCUSSION Table I shows that endrin and Phosdrin again gave good to excellent control of the caterpiller complex. Guthion gave fair control when applied alone, and good control in combination with DDT. However, the latter mixture is expensive and may not be applied to cabbage after the heads begin to form. DDT gave good control in 1958 and poor control in 1959. It is apparent that four applications of DDT, 2 lb. per acre, as suggested by Harcourt and Cass (8), will no longer guard against damage by the cabbage looper, presumably due to development of strains of the insect even more tolerant of the chemical. The combination of DDT and toxaphene gave only fair control in both years. The combination of malathion and Perthane gave excellent control of the caterpillars in 1958 and moderate control in 1959. On the basis of these experiments, malathion-Perthane dust was recommended to Ontario growers in 1959 (5) for control of caterpillars on cole crops after head formation. SUMMARY In 1958 and 1959, on the basis of foliage injury at harvest, four appli- -eations of insecticidal dusts to late cabbage at 15-day intervals gave the following degrees of control of the imported cabbageworm, the diamond- back moth, and the cabbage looper: 1 per cent endrin at 0.25 lb. of toxicant per acre and 1 per cent Phosdrin at 0.4 lb., good to excellent; a combination of 5 per cent DDT, 1.0 lb., and 214 per cent Guthion, 0.5 lb., and a com- bination of 4 per cent malathion, 1.0 lb., and 5 per cent Perthane, 1.25 lb., good; 3 per cent Guthion at 0.75 lb., 5 per cent DDT at 2.0 lb., and a combination of 214 per cent DDT, 1.0 lb., and 214 per cent toxaphene, 1.0 lb., fair to poor. ACKNOWLEDGEMENT The author is indebted to Dr. D. G. Harcourt, Entomology Research Institute, Ottawa, for helpful advice throughout this investigation, LITERATURE CITED (1) FEDERER, W. T. (1955). Experimental design. Theory and application. Macmillan, Toronto. 51 (2) Harcourt, D. G. (1956). Occurrence of a DDT-resistant strain of the cabbage looper, Trichoplusia ni (Hbn.) in the Ottawa Valley. Canad. J: asT. pci. 26: 430-434. (3) Harcourt, D. G. and Cass, L. M. (1959). Control of caterpillars on cabbage in the Ottawa Valley of Ontario and Quebec, 1956-1957. J. econ. Hnt. 52: 221-223. (4) Harcourt, D. G., Backs, R. H. and Cass, L. M. (1955). Abundance and relative importance of caterpillars attacking cabbage in eastern Ontario. Canad. Ent. 87: 400-406. (5) Ontario Department of Agriculture and Canada Department of Agri- culture. Protection calendar for vegetables (1959). Ontario Dept. Agric., Extension Branch, Toronto, Ont. | (Accepted for publication: March 10, 1961) THE APPLICATION OF pH DETERMINATIONS TO INSECT PATHOLOGY’ A. M. HEIMPEL’ INTRODUCTION The use of pH measurements in diagnosis and to give further informa- tion concerning diseases of insects has proved profitable, and the literature contains several references to this type of work. Most of these references will be re-evaluated here in the light of the more recent work in this par- ticular aspect of insect pathology. A study of the diseased insect naturally involves an intensive investi- gation of the healthy insect as well. It is here, I believe, that many of the published pH determinations lead the investigator astray. Several mistakes made in earlier reviews have been perpetuated in later work in this field. Further, many of the reports of pH determinations of insect body fluids were made with inadequate equipment, often of mixed material contaminated with products from crushed cells, tissue fragments, etc. In a sample of 75 gut contents readings on as many larval Lepidoptera and Coleoptera species, two-thirds of the determinations were made of whole gut or whole midgut brei. The resulting readings are insufficiently ac- curate for comparison with diseased material, because in most insects there are several pH regions in the gut which may (as in the case of most phytophagous Lepidoptera) vary from weakly acid to strongly alka- line. The various pH regions usually correspond to the anatomically dis- tinct regions in the gut (70, 30). Within this same group of 75 insects - mentioned above, 19 of the species were examined with the quinhydrone electrode which is reliable only up to pH 8.0, yet results above pH 9.0 were reported (65, 58, 62, 60). It is now possible, by the use of a variety of highly developed methods, to obtain reliable readings consistently from very small samples. Using these methods, it would be advisable for anyone investigating the abnormal insect to examine thoroughly the healthy insect first. 1Contribution No. 25, Insect Pathology Research Institute, Research Branch, Canada Agriculture, Sault Ste. Marie, Ontario, Canada. 2Present address: Insect Pathology Laboratory, U.S.D.A., Beltsville, Maryland, U.S.A. 52 The purpose of this paper is to gather together reports of the work done on the hydrogen-ion concentration of diseased insect material from the three Orders Coleoptera, Hymenoptera (mainly phytophagous), and Lepidoptera, An attempt will be made to compare these reports with data from healthy insects and in so doing, to examine critically the healthy insect data. The solution of the many controversial problems (such as blood and gut buffering agents) that turn up in such a discussion are beyond the scope of this paper, beyond pointing out that their solution is vital to continued progress in insect physiology and pathology. A number of insects have been investigated since the last publication on this subject (31) and these are included here. METHODS The following methods and equipment have been used to make pH determinations of insect body fluids: Indicators The blood pH of insects has been measured by introducing indicators into the blood before or after bleeding. Indicator papers also have been used for this method. Often pooled blood samples from several insects were used to obtain one reading. Indicators have been fed to insects and the resulting color changes of the gut contents noted. This method is reasonably accurate with insects that eat material not other wise coloured by chlorophyll or some pigment. It is particularly useful with small larvae such as Tinolea biselliella Hamm., Anagasta kuehniella (Zell.), and Carpocapsa pomonella (Linn.), where the transparent body wall and uncolored gut contents allow reasonable accuracy. When an insect possesses an opaque body wall, but feeds on uncoloured material, the gut pH may still be determined by feeding an indicator followed by dissection. It is well to remember, when using this technique, that in very smal! larvae it takes very little cellular rupture to alter the pH of the gut contents, and the blood pH is even more readily changed. Indicator methods may be employed if care and large samples are taken (i.e., 20 to 30 individual readings). The pocling of blood samples should be avoided, because the blood of the normal feeding insect is at a minimum with reference to buffering capacity; thus, relatively small amounts of atypical blood can significantly alter the pH of the pool. — Quinhydrone and microquinhydrone electrodes There are available quite accurate electrodes that require only a very small volume of fluid (e.g., the membrane quinhydrone-platium electrode, Beckman Co, [error +0.02 pH units]). Although these small-capacity elec- trodes require some patience and practice in their operation, their use more than compensates for the time taken to bleed 50 or more insects in order to obtain one reading by some other means. The quinhydrone electrode is very useful in measuring the reaction of complicated mixtures such as insect blood or gut contents. It is not readily influenced by oxidizing agents or by substances reduced by hy- drogen. It has, however, disadvantages that cannot be ignored, namely, the alkali error and the salt error. The electrode gives incorrect readings above pH 8, in the presence of proteins and in high salt concentrations. The hydrogen electrode All electrodes in use are calibrated in terms of the hydrogen electrode, and all inherent errors of other electrodes are determined by the per- «658 formance of this electrode. Several investigators (10, 12, 21, 22) have used this electrode in insect work, and their results should be reasonably accurate. However, the intricacies of the apparatus and time of equilibra- tion of the hydrogen electrode discourage its use for routine work. The glass electrode This electrode is probably the most versatile and accurate of all, other than the hydrogen electrode, now in use. It can be obtained in many forms varying from needle-shaped to cup-shaped, single drop electrodes. The Corning 015 glass used to construct the electrode allows good accuracy between pH 1.0 and 9.0. In very concentrated acid solutions the readings are slightly high. Alkalinity above pH 9 causes an error, due to faulty sodium-ion response, which results in readings that are slightly low. According to Bates (8) the replacement of the sodium constituent in the glass by lithium overcomes the alkali error. Single drop glass electrodes may be used to determine the pH of very small amounts of materials with reproducible results. The facility with which the electrode may be cleaned and used also lends itself to work with insects. DISCUSSION OF LITERATURE Factors affecting the pH of the body fluids of healthy insects Although the pH of the blood of most insect species is remarkably similar, and the blood pH of each species is quite stable, the pH of gut contents tends to be relatively variable so that each instar of each species requires a separate investigation. The findings for B. mori (see Table I) show that in the early instars the midgut contents are far less alkaline than in the later instars. On the other hand, the blood of B. mori larvae decreases in hydrogen-ion concentration with increase in age (instar) of the insect, contrary to the findings of Nunome and Horiba (47). | The crop or foregut The pH of the foregut is influenced both by the food (Roeder, [52], p. 825; [31]) and by the frequency of feeding. In larval insects that feed continuously or take many ‘meals’? within the day, the pH of the crop is nearly constant as long as the same type of food is supplied. There are insects, however, that are discontinuous feeders, that is, they take four or five meals a day with distinct periods of rest, up to five hours in length, between feedings. Insects of this type (e.g., the Malacosoma spp.) have a crop pH of approximately 6.7 when feeding and for one-half to one hour thereafter. As they return to their nests and rest, the crop changes gradu- ally to pH 8.5 to 9.0 (32); this variation can lead to conflicting results unless the habits of the insects are studied before pH determinations are made. The midgut The pH of the midgut in Coleoptera (Tables II and III) apparently shows some relation to the natural food of the insect. Staudenmeyer and Stellwaag (60) stated that phytophagous and wood-eating Coleoptera have alkaline midguts, whereas the carnivorous species give a weakly acid reaction. 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Those predacious and parasitic Hymenoptera larvae (Table IV) that have been investigated mostly have slightly acid midguts, and the phytophagous sawfly larvae all have slightly acid to alkaline midguts. Again the feeding habits of the insect may influence the pH of the midgut contents. Using the same insects as an example (i.e., the Mala- cosoma spp.), as the larvae return to their nests after feeding, the pH of the midgut, where digestion is proceeding, rises to the maximum found in these insects (pH 9.5-10.4 in the last instar larva). After 96 hours starvation (e.g., WM. disstria), the pH range in the midgut is 8.4-9.4 as compared to 9.5-10.4 in the insect immediately after feeding. Similarly, most phytophagous Lepidoptera and Hymenoptera larvae, when starved, show a distinct lowering of pH in the midgut (30). The opposite was noted in B. mort by Itaya (37) who reported an increase (based on whole gut measurements) from 9.2-9.8 to pH 10.0. Although the increase does take place in B. mori shortly after being removed from foliage, the pH 9.2-10.2 already exists in the feeding insect (30). Removing the larvae from the food actually increases the midgut pH from 9.2-10.2 to 9.5-10.4 for a limited period (about an hour). If the food is withheld longer from the insect, the pH of the gut becomes lower. Both Itaya (37) and Galzova (24) stated that they observed a flutua- tion of pH in the midgut of fifth instar silkworm larvae on the fourth day of feeding; they both stated that the pH dropped 0.2 to 0.3 pH units. It has not been possible to duplicate these findings, using the glass elec- trode and examining the various pH regions in the gut of fifth instar silkworm. Since both workers used whole-gut preparations for their studies, the peculiar phenomenon they noted might be explained by the unreliability of readings from mixed gut contents. Buffering capacity of the midgut It is not unlikely that the larval midgut supplies buffering materials “on demand”’’, that is, whenever feeding is taking place and for as long as there is undigested food in the digestive tract. This probably means that the buffering effect measured is that buffering capacity remaining after the food in the gut is converted to the required pH, or in the words of Day and Waterhouse (in 52) ‘“‘the residual buffering power of the gut’. This possibility makes the determination of the buffering agents very difficult. Hoskins and Harrison (36) showed that there were two systems active in the bee ventriculus, one an organic acid salt system and the other a mono- and di-hydrogen phosphate system, buffering the ventriculus contents to pH 6.3. However, phosphates are not important buffering agents in a variety of other insects (49, 60). Further, one would hardly expect mono- and di-hydrogen phosphate systems to buffer regions of the migut contents to pH 10 and above, which occurs in so many Lepidoptera larvae. Staudenmayer and Stellwaag (60) reported a lack of effect of phosphate buffers in several lepidopterous larvae and in Carausius sp., and concluded that the buffering is produced by a complicated system of weak acids, salts, and proteins. However, such a hypothesis does not fit the evidence concerning B. mori, M. disstria, and other Lepidoptera larvae investigated here. In B. mori and M. disstria there are narrow regions in the midgut (approximately %g inches long in both insects) that are maintained at pH 10.3 and 10.2 in the feeding fifth instar larvae. It is noteworthy here that there is a difference of one full pH unit between the fore- and mid- 65 «PPD 91N7B104UT,, 99S q sjoquiAs FO uoreueldxe 10J [ sqey, 909 » TS"9-€P'9 T8°L-09°L LT8-06L T8'9-79'9 L8°9-08°9 TOMYOY Lv TLL L6°L VL'9 v8°9 0€ ID g DUNIULbLIA WoLLdypod NT 19°9-L8°¢ LV L-OGL GO L-9OT9 GaL-VI'9 vo'9-87'9 Gai) st eae GOL oor 8Pr'9 18 ID se] VOUIDMS UOLLdYpoa NJ 8T9-L8°g 69 L-6V'L OT 8-8 L YIGL-OT'L §8°9-LL'9 v0'9 9g°1 VI8 8th [3°9 0€ ID 9 4Of444OS UWOLLAYPOI NT 68 L-V8'9 SV'8-c08 GOL-ceL OL 9-79'9 §69-€8°9 00°L 628 6V'L 09) 9) 88°9 0€ ID 9 YOU 227U090] UoLsdipoa Ny GV'9-0¢°9 OT8-09°L PLL-09'L 08°9-09°9 LG Or0S "9 LIMYOY sunisyuUung 6&8 9 GLb GOL 09°9 icp) 0& 19 q SNUDILMAUN WOLLdipod AT heer ero bt) OOLSTLL Go8-962 Geo sl 9 62°9°L79 wire 68°L VV'3 V9 69°9 0& ID 9 (‘118 }]{) sya1qn Uorsdipoo nN LL’G-TL'¥ GVL-9V'9 OL 8-9VL 868-70L P2L-0V'9 9F'9-GE°9 82'g LOL 60°8 69'L L9°9 1V'9 ifs ih ala (VION) snaynf snuazo0u0 py $0.0°99°9 98°8-CI8 SO L-ITL 89°9-88°9 §1°9-99°9 09°9 G2'8 Gh L cr'9 OL'9 08 TD, 79 (31H) syvuis worudiqg $8 05c7 9 OG'8-9T'8 ET L-00°L 88° L-09°L Lg o7Sy 9 (34H) anruhasoy 99°9 Gg"8 VOL 99°L 09°9 OSes \ipmr ug (nrmidjiy) wor.diqg sepluolidiq VE 9-VV'G 691-999 998-07 L €9°6-0L'8 LL L-2EL 68'9-28'°9 06°S 00°L 861 G6'8 99°L g8°9 HS fo Pata (yoVeyT) syp.ojzood obay 08°9-V2'9 66L-ECL GOL-OGL OV L-SI'9 §8°L-00°L (qe) svwsonanzo 299 69h 69h GL'9 9T'L Rea yo) Seo Ajqissod “ds abup sepid1y wunyoy pue AndpIy, Isp, I = et sarLoWny qn.dpulyy LOLIOISOG UviIpey, A0ltojuy doa poolg Ss g 4 Iey10 ° ° Hi neice dal! eduey pue urop ae = Hd Sei a eeilojdouswmiAy 4[npe pue [earl JO poolq pue syusqUOD ORI} BANSESIP oY} JO F{d ou, AI Wav, co co SS SS ea ce a raga ee eS I ee Ens eae eee ee 069-26 ¢ 6I'9 TL°9-00°9 Tee 0€°L-L9°9 669 68 °9-L9°9 OL'9 VOLS Toa G8°S-97'¢ GL'g OF'8-068 Te L-OTL 6&8 OS°8-cV'L 868 GL°L-8V'L 9S°L 68°8-0G°8 §6°8-€9'8 6L'8 LL-&°9 TL V8'9-0L'9 §8°9-§L°9 6L°9 Neh GL 8 6L°9 66 L-60°L IGh 68° L-8TL I9'L 0O6L-CTL GLb 88°L-SLL 68°L GL-E9 Des) y9°9-94°9 yo) @O SPiee) Ve SE9°€vV 9 TE 069-099 Tf 6959-199 v99 0€ LG9-GV'9 609 0€ 89°9-GV'9 oo 0€ 69°9-€9°9 L9°9 0€ LG &4'9299'9 69°9 0€ OW ‘d ‘dd (Arn.1iq ) WUND{UEWMEDD UOLYdYAIS (Ainiq) UNLDIUIWADI UOLYAYIIS seplveydsg ((34}]{) wuosyor.sa DLoydisisgd (31H) muosynsa DLoydrjsrtg IOMYOY Sisuaysyjy DWUIU0A1q (doog) msaqus (Dapuuote7d) snqzpvwa pT (4I0N) snumuoa snjzhydwmosonpy (INOW) 029019 DOLYyoUMea FT IE) DUO DURES 67 ee a ea ee a ee unjooy pue ynspIA Isp, = wspryl PS oe s, jnspulH =«AOLIOJSOq uvIpey 10110} doin PO 2s sorqtioyyny eee eee peesa aah 0) esuey pue uve a. se Hd = (ponuluopD) AT AIavyL region in B. mom and between the mid- and hind-region in M. disstria. Further, contrary to Itaya’s findings (37), X-ray studies conducted here on both insects, fed foliage smeared with barium sulphate, indicate that food reaches the center of the midgut in 14 to 18 minutes and passes through the gut in 80 to 100 minutes (33). If barium sulphate has any effect on the speed of movement of food in the gut it tends to slow the process (59). Consequently, there is a relatively rapid flow of food, in B. mort, first from the crop (pH 6.9) into the fore-midgut where it is raised sharply in pH to 9.4, then within a few minutes passes into the mid-region where it is again abruptly raised to pH 10.3. The same effects, in reverse, are to be seen in M. disstria and some other Lepidoptera larvae. It seems remarkable that such rigid control of relatively large differences in pH could be maintained in the midgut by a complicated system of weak acids, salts and proteins. It is more reasonable to postulate that one or two agents are responsible for the buffering effects and that they are produced, “on demand” by the cells in the various pH regions. Such agents capable of maintaining high pH in the midgut have already been reported. Without laying undue emphasis on the work, Arsenev and Bromlei (5) reported a 0.12 to 0.15 M solution of potassium carbonate in the midgut of the silk- worm and similar findings in the Chinese oak silkworm A. pernyt. At 25° C., a 0.025 M sodium bicarbonate — 0.025 M sodium carbonate solution has a pH of 10.02. From Arsenev and Bromlei’s findings the carbonate system could be postulated as a major buffering agent. They make no attempt, however, to explain the availability and supply of free CO: to support such a system. Wojtczak (74) found pyrophosphates with equal amounts of a polyphosphate in the labile phosphorous fraction of the excreta of the waxmoth, Galleria mellonella L. A pyrophosphate buffering system would maintain the high pH found in silkworm larval midguts but on turning to Itaya (37) we find the phosphorous content of ashed silk- worm gastric juices to be only five per cent; this is not final, however, since Itaya’s figures differ radically from those given for the same ma- terial by Arsenev and Bromlei (5). Unfortunately for the pyrophosphate theory, Galleria mellonella does not have an exceptionally alkaline midgut (highest pH 8.4). Obviously a great deal of careful work must be done before midgut buffering in insects is clearly understood. The hindgut and rectum The pH of the hindgut and rectum may be slightly acid to weakly alkaline, and is usually lower than that of the midgut. Diet as well as excretion of uric acid have been cited as the cause of this lower pH in the latter part of the digestive tract (52). Blood Variation in the blood pH of insects is relatively slight compared to that in the digestive tract. Interspecific variation, according to the liter- ature, is 1.18 to 1.4 pH units in Coleoptera (adults and larvae respec- tively), 1.96 pH units in Lepidoptera larvae and 0.98 in Hymenoptera larvae. The intraspecific variation in all three orders is approximately 0.2 pH units. The blood of approximately 90 per cent of the insects from these orders is slightly acid. During metamorphosis, a slight decrease in pH may occur at some time in the prepupal or pupal stage (67, 43, 1, 9, 16). According to these investigators, insects can tolerate considerable changes of pH to the acid side. However, Gamo, et al., (25) and Heimpel and Angus (4, 32, 33) have shown that several insects are susceptible to alkaline changes of 0.75 to 1 68 pH unit; a change to the alkaline side of 1 pH unit or more results in total paralysis followed by the death of the insect. Blood buffering capacity A concise review of this subject is given by Roeder (52); however, a few points might be touched on again. The buffering capacity of the blood is apparently at its lowest at the normal pH of the larval insect. Apparently _ there are a number of systems acting as buffers in insect blood, and these various systems are of variable importance in different species. Among the systems suggested are phopshate and free amino acids; however, it has been established, in the insects examined, that these systems do not play an active role. Bicarbonate acts as a buffer in Gasterophilus (41) and in the honey bee, Apis mellifera Linn., (9), but has a negligible action in Prodenia (6). Organic acids, succinate, and proteins, have also been shown to have a buffering effect. Again it appears that a careful examination of each species is neces- sary if the major buffers are to be determined. In all the insects examined, the buffer titration curves are relatively smooth compared to those found in vertebrates and this would indicate that there are several systems involved in the buffering action of insect blood. Although all insects examined have minimum buffering capacity at their normal blood pH, it does not follow that the buffering capacities are the same in all species. Careful titrations of the blood of B. mori, M. americanum, A. pernyi and P. sexta were made here and it was found that the buffering capacities among these species were substantially dif- ferent (33). However, the intraspecific variation in buffering capacity, for a given instar, was surprisingly constant. It follows that feeding habits and the condition of the insect should be taken into account during the measurement of the pH of insect body fluids. Changes in the pH of the body fluids of diseased insects There are several references in the literature on the effect of disease on the pH of insect gut contents and blood. Payne (48), reporting on cold- hardiness of Japanese beetle larvae, Popillia japonica Newn., noted that there were no changes in blood pH correlated with cold- hardiness in apparently healthy larvae. She reported some larvae collected for these experiments became infected with ‘‘wilt disease” or ‘‘polyhedrals krank- heit” (polyhedrosis). Whereas the healthy third-instar larvae had a mean blood pH of 6.87 (range 6.35-7.18, 20 specimens), the diseased larvae had a mean blood pH of 5.89 (range 5.56-6.1, 19 specimens). It apparently took ten days for the symptoms to develop. According to Payne, “Wilt disease is characterized by pronounced blackening preceding final soften- ing that occurs just before death’. Since there is no known polyhedrosis of Japanese beetle larvae, it may be that the disease she described was caused by the type-B, milky disease agent, Bacillus lentimorbus Dutky. At any rate, the symptoms could easily be checked by any interested person who is currently working with the Japanese beetle. Galzova (24) reported a drop in gut pH from 9.9 to 7.5 in silkworms infected by ‘“‘flacherie”. It is now known that ‘‘flacherie” is caused by the erystal-forming, sporulating bacteria (Bacillus thuringiensis var. sotto and B. thuringiensis var. alestt) (34). This change in gut pH has been confirmed by Angus and Heimpel (8). Galzova went on to state that “bacteriosis’’ in silkworm larvae did not cause a change in gut pH. This contradictory statement is incorrect 69 since growth of bacteria in the silkworm gut or blood is invariably accom- panied by changes in pH (28). In this connection, Heimpel (29) showed that there is a distinct change in pH in the digestive tract of the larch sawfly, Pristiphora erichsoniu (Htg.), infected by Bacillus cereus (see Fig. 1); HAEMOLYMPH PH TIME IN HOURS Fig. 1. Changes occurring in the haemolymph and gut of the larch sawfly during an infection caused by Bacillus cereus. Solid line — pH of respective fluids in healthy insects. Dotted lines — discrete tests of the various fluids in infected insects. 70 Galzova showed that “‘pebrine” does not change the pH of the body fluids of silkworm larvae. Jameson and Atkins (38) reported similar findings with silkworm infected with this microsporidian (Nosema bombycis Naegeli). Lysenko (44) pointed out that Streptococcus spp. and Staphylococcus spp. are present in healthy silkworm guts and are sometimes capable of multiplying and killing the insect: He also stated “. . . my experiments showed that large doses of streptococci, which silkworms would not meet under natural conditions, must be used to produce the disease’. According to Lysenko, these bacteria can maintain themselves in the silkworm gut (pH 9.2-10.4) by virtue of their tolerance to relatively high pH conditions (pH 9.6). Should the silkworm be placed under stress such as a virus in- fection, or ingest extremely large numbers of these bacteria, Lysenko believes, the bacteria begin rapid growth, altering the pH of the gut con- tents until optimum conditions are created resulting in the death of the insect, Most bacteria, pathogenic for insects, assert themselves in one of at least two ways when introduced into the insect gut: 1. They may grow in the gut, changing the pH of the gut contents to their optimum pH, as well as damaging the gut cells with extra- cellular toxic metabolites, and eventually causing death (138). 2. They may not grow at first, but damage the gut by virtue of toxic substances previously produced in the bacterial cell. An example of the first case was demonstrated by Heimpel (29). B. cereus, growing in the gut of larch sawfly larvae, P. erichsonii, produces lecithinase, an enzyme which breaks down the gut cells and eventually other tissues in the body, finally causing death in 48 to 96 hours. As an example of the second case, Angus (2) showed that crystals, or spores and crystals, of B. thuringiensis var. sotto cause paralysis of silkworm larvae in 60 to 70 minutes, Later, Angus and Heimpel (3) demonstrated that this general paralysis is caused by the damaged gut permitting the highly alkaline, well buffered gut contents to leak into the poorly buffered blood, thus causing an increase in blood pH. At the same time, there is a very rapid fall of from 1.0 to 1.5 pH units in the pH of gut contents. They showed that the body paralysis could be induced by injection of sufficient non-toxic buffer to bring the normal silkworm blood (pH 6.7 in the fifth instar) to pH 8.0. The ensuing artificially-caused paralysis was permanent and fatal. Further, it was found that the horn- worm, Protoparce quinquemaculata, and the Chinese oak silkworm, Antheraea pernyi, also become afflicted by general paralysis when fed erystal-forming bacteria (4). Although the paralysis in these insects begins later (5 to 7 hours), the rise in blood pH and the fall in gut pH occur concurrently with the onset of paralysis. It is now realized, however, that general paralysis as a symptom is the exception rather than the rule for Lepidoptera susceptible to the action of the crystal-forming bacteria. Many Lepidoptera, when fed crystal-forming bacteria, stop feeding per- manently a few minutes after consuming contaminated foliage. There is evidence that the cessation of feeding is caused by paralysis of the digestive tract (69, 33), but there is no suggestion of general paralysis, and there is no increase in pH of the blood, which remains normal in reaction until death of the insect in approximately 96 hours. There is a slow drop in pH in the digestive tract of the latter insects, but this change in reaction is indistinguishable from the reaction to starvation in the same insects and occurs gradually over a four-day period, unlike the 60-minute gut pH change in B. mori. (at CONCLUSIONS One fact became evident upon reading the literature reviewed in this paper; there is an inordinate number of misquotations in the literature that tend to be perpetuated. Accordingly, original papers were consulted in all cases and for this reason the section on Russian contributions is admittedly not complete. It is readily apparent, even from such meager beginnings, however, that the use of pH determinations as a diagnostic tool in insect pathology can be rewarding. A whole section of this field remains virtually uninvestigated, and I refer to intracellular pH determinations and their application to insect pathology involving intracellular organisms (e.g., microsporidia, viruses, etc.). Indeed, almost any area in these investigations requires a great deal of careful work. This applies particularly to the buffering agents in the gut and blood of insects. It is impossible to draw any useful information from the current literature that might serve as a firm basis for further work. However, it is evident that new findings may have wide application to insect physiology, toxicology and insect pathology. SUMMARY The pH of the body fluids in normal feeding insects is relatively constant. Insects placed under stress by disease and/or starvation, etc., often show characteristic changes in gut and haemolymph pH. A survey of the literature on the effect of disease on the pH of insect fluids is given. In order to compare diseased insect data with that from healthy insects it is necessary to have accurate records of the pH in the latter. Accordingly, a survey of the literature on the pH of fluids in normal feeding insects is also included. LITERATURE CITED (1) AGRELL, L. (1948). The fluctuation of pH, buffer capacity and pH dependence of hydrogen activating enzyme systems during meta- morphosis. Acta Physiol. Scand. 16: 9-19. (2) ANGus, T. A. (1956). The reaction of certain Lepidopterous and Hymenopterous larvae to Bacillus sotto toxin. Canad. Ent. 88: 280-283. (3) ANGUS, T. A. and HEIMPEL, A. M. (1956). An effect of Bacillus sotto on the larvae of Bombyx mort. Canad. Ent. 88: 138-139. (4) ANGUS, T. A. and HEIMPEL, A. M. (1959). Inhibition of feeding and blood pH changes in Lepidopterous larvae infected with crystal form- ing bacteria. Canad. Ent. 91: 352-358. (5) ARSENEV, A. F. and BROMLEI, N. V. (1957). The chemical compo- sition and the buffer capacity of the intestinal fluid of caterpillars of the oak and mulberry silkworms (Antheraea pernyi and Bombyx mort). Rep. Seric. and Apiculture Section of the V.I. Lenin Akad. Sel. Khoz. Nauk. Agric. Sci. 2: 101-114 (6) BABERS, F. H. (1938). 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Physiol. 24: 422-450. SCHLOTTKE, E. (1937 b). Die Abhangigkeit des Fermentgehaltes von der Nahrung, Versuche an Periplaneta orientalis L. Z. Vergl. Physiol. 24: 463-492. SHINODA, O, (1927). Contributions to the knowledge of intestinal secretion in insects. I]. A comparative histo-cytology of the mid- intestine in various orders of insects. Zeitschr. Zellforsch. 5: 278-292. SHINODA, O. (1930). Contributions to the knowledge of intestinal secretions in insects. III. On the digestive enzymes of the silkworm. J. Biochem. 11: 345-367. SINHA, R. N. (1959). The hydrogen-ion concentration in the ali- mentary canal of beetles infesting stored grain and grain products. Ann. Ent. Soc. Amer. 52: 763-765. SKJRABINA, FE. (1936). pH of the insects’ intestines and blood and its modification by polsonng with arsenic and fluorine compounds. Bull Pb Prot. leningr. 3: 9. (In Russian): 75 (59) SNIPES, B. T. (19387). 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Hydrogen-ion concentration within the digestive tract of certain insects. Ann. Ent. Soc. 24: 489-495. (66) SWINGLE, M. C. (1931 b). The influence of soil acidity on the pH value of the contents of the digestive tract of Japanese beetle larvae. Ann, Ent. Soc. 24: 496-502. (67) TAYLOR, I. R., BIRNIE, J. H:, MITCHELL, P. H. and SOmINGER ts (1934). Hydrogen-ion activity changes in Galleria mellonella dur- ing metamorphosis, as determined by a glass electrode with micro- vessel. Physiol. Zool. 7: 593-599. (68) TRAPPMANN, W. and NITSCHE, G. (1953). Methoden zur Prifung von Pflanzenschutzmitteln V. Beitrage zur Giftwertbestimmung und zur kenntnis der Giftwirkung von Arsenverbindungen. Mitt. biol. Reichsanst. Berl. 46: 61-69. (69) VANKOovVA, J. (1957). Study of the effect of Bacillus thuringiensis on insects. Folia Biol. 3: 175-182. (70) WATERHOUSE, D. F. (1940). The hydrogen-ion concentration in the alimentary canal. IJ. The absorption and distribution of iron. Aust. Coun. 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DAVIES’ INTRODUCTION Ontario abounds in a wide variety of aquatic and semi-aquatic habitats from which come vast numbers of biting flies each year. These flies, Tabanidae (horse flies and deer flies), Culicidae (mosquitoes), Ceratopo- gonidae (punkies), and Simuliidae (black flies) form a voracious and fearsome group of blocd-sucking insects that cause incalculable losses to man and livestock. Though of lesser importance than the mosquitoes and black flies as pests of man, the tabanids by virtue of their biting and persistence cause great annoyance and loss in productivity to humans in the field. The tabanids are supreme amongst the biting flies as pests of livestock, and in many areas may hold this supremacy over all other insects affecting livestock. Although the importance of the Tabanidae within the province is well known to all who have spent some time in the field, it is not evidenced in the literature. No account of the Ontario Tabanidae has been published and few regional lists are available. The seasonal distributions of nine species at Byron Bog, near London, were given by Judd (6). Davies (8) wrote on the seasonal variations of tabanids in Algonquin Park and also recorded some unusual host records. The seasonal distribution and relative abundance of tabanids collected on farms in southwestern Ontario were reported by Teskey (24). The earlier records of Tabanidae in Ontario have been provided by Brennan (1), Stone (28), Philip (15, 16, 19, 20), Judd (5), Pechuman (10, 12) and Davies (3). In the present paper these records are assembled, five new species records are reported, the known distribution of the species in the province, and keys for the identification and brief descrip- tions of species that occur and may occur in Ontario are given. LIFE HISTORY The life history of relatively few species of Tabanidae have been extensively studied. Incomplete information is available on others, while the immature stages of the majority of species are unknown. Although much is still to be learned of the life histories of many species, a consider- able literature on this subject is presently available. For those who desire more information than provided in the following brief summary they are referred to the work of Marchand (8), Webb and Wells (25), Cameron (2), Stone (22), Philip (13), Schwardt (21), Jamnback and Wall (4), and the references to other works that these papers contain. A. Immature Stages | | In the majority of species eggs are laid in masses on vegetation, rocks, trunks of trees, logs, and other objects overhanging water or moist ground. The egg masses comprise from one to several tiers of usually symmetri- cally placed eggs (Figs. 1 and 2). The structure of the mass, its shape, number of tiers, position of individual eggs in the mass and its color are characteristic for most of the species known. The site of deposition of egg masses are also characteristic of some species. The egg masses of Chrysops 17 Davison Road, Lockport, New York. 2Entomology Laboratory, Research Branch, Canada Department of Agriculture, Guelph, Ontario. 8Department of Biology, McMaster University, Hamilton, Ontario. Proc. ent. Soc. Ont. 91 (1960) 1961 77 moechus O.S. are placed at considerable heights on the leaves of trees over- hanging rivers and streams. The conspicuous shiny black, tiered egg masses of Hybomitra lasiophthalma (Macq.) are typically placed on vege- tation growing under damp, semi-swamp conditions. Egg masses are white or cream colored when first deposited but soon darken to various shades of brown or black. The eggs hatch about a week after oviposition and the larvae drop to the ground or water below. All of the eggs in a mass usually hatch within minutes of each other. The larvae of Tabanidae are segmented, elongate, cylindrical, and tapered at both ends and may be colored white or various shades of brown or green. Behind the head, which is brownish and capable of complete retraction within the body, are three thoracic segments and eight abdomi- nal segments. All but the last abdominal segment bear conspicuous fleshy prominences or “parapodia’”’. The last abdominal segment bears ventrally © the anal aperture and posteriorly a short respiratory siphon, The larvae of most species studied can be distinguished by the presence or absence and amount of pubescence present on the body segments. This pubescence is quite heavy and conspicuously pigmented on such larvae as T. atratus Fab. and T. reinwardtu Wied. and almost absent on T. marginalis Fab. (Figs..3, 4.5): Larvae have been found under a wide variety of conditions ranging from a completely aquatic habitat to relatively dry soil. A wet habitat is preferred by most species. However, such species as Hybomitra lasioph- thalma, Tabanus lineola Fab. and T. quinquevittatus Wied. are frequently found in habitats which during part of the year may be nearly dry. Some species appear to be restricted to a particular type of habitat whereas others can tolerate a wide variety of larval habitats. Larvae of Hybomitra minuscula (Hine), have been found only in sphagnum bogs. Atylotus thoracicus (Hine), A. bicolor (Wied.) and Hybomitra astuta (O.8.) al- though they may also breed elsewhere, show a distinct proclivity for such bogs. The larvae of T. fairchildi Stone have been found only in fresh water streams and rivers. The larvae of many species, especially those of Hybomitra and Tabanus, are carnivorous, Chrysops spp. are believed to feed mainly on decaying organic matter, or the bacteria associated with such decay. The time required for tabanid larvae to complete their development under conditions in Ontario is not known. It is probable, however, that as with the New York fauna, many species require one year and others may require two or more years to complete larval development. When full grown the larvae of many species move to drier conditions in which to pupate. The Tabanidae have obtect pupae (Fig. 6) that are colored various shades of brown or green. Each abdominal segment is encircled by a row of stiff spines and the terminal segment bears six, stout, sharply pointed projections, termed the pupal aster. The pupal stage requires from one to three weeks depending on the species involved and the temperature. B. Adults In Ontario, the larger species, mainly in the genera Hybomitra and Tabanus, are commonly called horse flies while the banded-winged smaller flies (genus Chrysops) are known as deer flies. These common names are of course inadequate since tabanids by no means confine their attacks to these animals. Most mammals may act as hosts for the voracious biood- sucking tabanids. The role of birds and cold-blooded reptiles and am- phibians as blood sources for tabanids is probably negligible. Although tabanids apparently attack many mammals indiscriminately, some host 78 a. Figs. 1-6. Immature stages of Tabanidae. Egg masses of: 1. Chrysops sp.; 2. Hybomitra lasiophthalma (Macq.). Mature larvae of: 3. Tabanus atratus Fab.; 4. T. reinwardtu Wied.; 5. T. marginalis Fab.; 6. Pupa of T. marginalis Fab. differences have been observed. Horse flies are considered as more trouble- some pests of livestock wheras deer flies cause human beings greater annoyance. This difference may in part be due to attack behaviour. Horse flies are conspicuous and noisy in their attack and thus more easily apprehended by humans than are the stealthy deer flies. Livestock are however more defenceless. Also, most horse flies appear to be attracted to larger objects than deer flies, and thus are likely to be greater pests to larger animals. The Tabanidae are generally known by their blood-sucking behaviour. Only the females suck blood, this blood being utilized for egg development. However, there is no real evidence that a blood meal is essential for the maturation of the eggs of Tabanidae. It may well be that blood is not always necessary. The females of some species have not been observed to annoy mammals. Both the males and females feed on the nectar of flowers and other sweet exudations such as honeydew. Little is known of the mating behaviour of the Tabanidae. In many of the species that have been observed to mate, the sexes meet in flight and then land on some object to complete the act. This flight involves the hovering of the males in some species. Such males, hovering over con- 79 spicuous objects or areas at particular times of the day, chase and make contact with females that fly nearby. Although male hovering and mating have been associated for only few species it is probable that it may occur commonly in species of the family. The males of H. affinis aurilimba (Stone), H. arpadi (Szilady), H. cincta (Fab.), H. criddlei (Brooks), H. lastophthalma (Macq.), H. epistates (O.8.), H. nuda (McD.), T. lineola Fab., and others, have been observed to hover over the tops of elevations, trees, and in woodland clearings. Tabanids are most active on warm sunny days. The numbers of attacking females are greatly affected by slight drops in temperature, an increase in wind speed, or a reduction in the sunlight. There are however exceptions to this, for certain species appear to be crepuscular in habits and others attack more viciously during the approach of a storm front. Because of the female’s requirements for blood and thus her asso- ciations with man and livestock, this sex is more frequently collected. They often enter buildings, particularly buildings housing animals, and may be collected from windows to which they are attracted by light. Cobwebs in poorly cleaned barn windows are a source of large numbers of dead but well preserved specimens. Females have been obtained in large numbers inside or around parked automobiles, darker vehicles being more attractive. The attraction appears to be a thermotaxic response to the warmth radi- ated by the surface. Although Tabanidae may fly considerable distances, collecting is usually more productive when done near their breeding habitat. Most collections of Tabanidae contain few males. Males do not suck blood, nor are in any other way associated with man and his habitations. As with the females, collection of males is only productive if their habits are known. The males of several North American Tabanidae, including H. hearlet (Philip) and T. fulvicallus Philip are unknown. Only one male each of C. shermani Hine, and C. sordidus O.S. are known to have been collected. Males of C. excitans Walker, C. montanus O.S. and H. affinis (Kirby), three other abundant species in Ontario, are very rarely collected. Male tabanids feed on the nectar of flowers and may be collected on them. Light traps have proven useful in obtaining both sexes of certain species. Males and females are often encountered resting on paths and roads, especially where they pass through wooded areas. Both sexes have fre- quently been observed to swoop down over pools of water actually skim- ming the surface. Water poured into depressions in roadways forming artificial puddles is attractive to both sexes. Teneral adults can be obtained in the morning by sweeping vegetation in larval habitats. The tedious and time-consuming job of rearing larvae will produce both sexes in about equal numbers. TAXONOMIC CHARACTERS Few morphological structures of taxonomic value are to be found in the Tabanidae and these are largely confined to the head. Such struc- tures are supplemented by body coloration and wing patterns. The latter are especially useful in separation of members of the genus Chrysops. Body coloration is subject to considerable variation among members of a species and should be used with caution especially in identifying poorly preserved specimens. Most of the characters used in the following keys will be understood by referring to Fig. 7. The keys and descriptions of Ontario species of Tabanidae have been modified from Pechuman (11). In the brief description of each species, only the more obvious characters and those that will supplement the key 80 descriptions for separation of related species are given. Characters given for the male include only those showing obvious differences from the female. OCELLAR TUBERCLE -MEDIAN CALLUS BASAL (FRONTAL) CALLUS FRONS EYE SUBCALLUS FIRST ANTENNAL SEGMENT GENA - FRONTOCLYPEUS FRONTOCLYPEAL PIT SEGMENT PALPAL SEGMENT PROBOSCIS ANTERIOR VIEW OF HEAD OF Hybomitra illota. ANNULI BASAL PORTION THIRD ANTENNAL SEG. ANTENNA OF Hybomitra illota. NG. VEIN R BRANCH) Su: LO (LOWE APICAL SPOT CROSSBAND WING OF Chrysops prke/. Fig. 7. Characters used in the identification of Tabanidae (re-drawn after Pechuman). 81 CLASSIFICATION AND DISTRIBUTION The classification of the Tabanidae in North America is generally conceded to have begun with Osten Sacken (9). Other major contributions to the classification of nearctic Tabanidae were made by Philip (14), by Stone (23) to the Tabaninae and by Brennan (1) and Philip (18, 19) to the Pangoniinae, The most modern classification, based on a study of the World fauna, is by Mackerras (7). Eighty-seven species of Tabanidae now have been reported to occur in Ontario. These species are arranged as follows: subfamily Pangoniinae, two species of Stonemyia and one species of Goniops; subfamily Chryso- pinae, one species of Merycomyia and 33 species or subspecies of Chrysops; subfamily Tabaninae, one species of Haematopota, five species of Atylotus, 25 species or subspecies of Hybomitra, and 19 species of Tabanus. Because collections of Tabanidae from much of Ontario are either non-existent or inadequate, it is probable that several species are present in the province that have not been reported. Only few specimens are avail- able from widely-scattered localities in northern and western Ontario. In the southern portions of the province where the range extensions of southern and Atlantic coast faunal species would first become evident, little collecting has been done in recent years. Judging from the distri- butions of Tabanidae in states and provinces bordering Ontario, the follow- ing species may occur here: Chrysops aestuans subsp. abaestuans Philip, C. dacne Philip, C. flavidus Wiedemann, C. luteopennis Philip, C. pudicus Osten Sacken, Atylotus ohioensis (Hine), Hybomitra aequetincta (Becker), H. difficilis (Wiedemann), H. itasca (Philip), H. opaca (Coquillett), H. sexfasciata (Hine), Tabanus sackeni Fairchild, T. sparus Whitney, T. sparus subsp. milleri Whitney, T. swperjumentarius Whitney, T. trimaculatus Palisot de Beauvois, and T. vittiger subsp. schwardti Philip. All of these species are included in the keys. The collection records of the species of Tabanidae are listed by county and district after the brief description of each species. To facilitate their location on the map of Ontario (Fig. 8), the counties and districts in each list are arranged in a general directional order from south to north. The five species being reported from Ontario for the first time are preceded by an asterisk. ACKNOWLEDGEMENTS The distribution of the Tabanidae listed have been compiled from collections made by the authors and from specimens in the collections of the University of Western Ontario, London; McMaster University, Hamil- ton; Ontario Agricultural College, Guelph; University of Toronto; Royal Ontario Museum, Toronto; and the Canadian National Collection, Ottawa. We gratefully acknowledge the persons who so kindly permitted us to examine these collections. Unfortunately, no records were kept of the individual collectors of much of the material examined, so it is only possible to extend a general acknowledgement for their great contribution to the knowledge of the tabanid fauna of Ontario. KEY TO THE GENERA OF ONTARIO TABANIDAE 1. <) Hind tibiaezwith.2 apicalyspurs yo. ee ee 2 Hind tibiae without apical’ spurs’ .2 4 es eee 5 2. ‘Flagellum of antenna with 8.distinct annul °2)..23 45) 2 3) ee 3 Flagellum of antenna with 5 or less distinct annul ........................ 4 82 MIIUIION “Onadns “al La, 4810 AVG YaONKHL s2gend LDdIaLisia Wali rrel iene] UOSPN}Y ooo ee ee —_——_-- uOJNH _ oYeT -_— N 1SiQ AXHNBAaANS ‘LS1Q Wwoolv ) ‘SPLIISIP PUB SOTJUNOD Jo UOT}EdO] 9Y} SUIMOYS OLIeJUCO Jo dep -g “31 Lge Chir 8 Siecle 83 3. Eyes of female with upper inner angles acute; frons broader than width of eye; wings with a dark pattern........ Goniops Aldrich (p. 84) Eyes of female normal; frons narrower than width of eye; wings hyaline. 2. Sean en i Cam eI aap Stonemyta Brennan (p, 84) 4, Flagellum of antenna with 5 annuli; smaller species with dark mark-— INS; ON Wang. Oe Pa ea le nek eee Chrysops Meigen (p. 85) Flagellum with 2 or 3 annuli; larger Tabanus-like species with hyaline wings; hind tibial spurs very small............ Merycomyia Hine (p. 85) 5. First antennal segment longer than thick; frons of female widened below, broader than high; wing gray with white maculations ............ Be ie ool cl gg Se el Ul: is SOO tae ane ce Haematopota Meigen (p. 98) First antennal segment usually scarcely longer than thick; frons of female higher than broad; wing pattern not as above or hyaline... 6 6. Basal callus usually absent, if present well separated from eye; eyes hairy ; no-ocellar tubercle: = Atylotus Osten Sacken (p. a Basal callus as wide or almost as wide as frons —. |.) 3 eee 7. Vertex with a distinct ocellar tubercle; eyes usually hairy, rarely ae SNe ET Mp eet ei Se ys VIA a Hybomitra Enderlein (p. 100) Vertex without a distinct ocellar tubercle; eyes usually bare, rarely AI coe ee ee Ce er ee Tabanus Linnaeus (p. 111) Genus STONEMYIA Brennan Key to the Species of Ontario Stonemyia 1.Legs reddish brown; posterior margins of abdominal segments with Pr ayish: Naive ee ee TASH (Lw.) Legs black; posterior margins of segments with yellow hairs ........... eae Oe AEE SO CE ay SI Se ena Shh se ARLE. ence ee Cen ea tranquilla (O.8.) Stonemyia rasa (Loew) Moderate in size (12.5 mm.); dark brown; abdominal tergites with grayish hind margins; legs reddish brown; wing membrane faintly tinted, costal cell yellow. Ontario Records—Lincoln, July 26; Wellington, Aug. 22; York, Aug. 10; Hastings. Stonemyia tranquilla (Osten Sacken) Moderate in size (12.5 mm.) ; blackish brown; abdominal] tergites with yellowish hind margins and considerable yellowishness or chestnut laterally; legs mostly black; wing membrane faintly tinted, costal cell yellow. Ontario Records—Muskoka, June 28-July 4; Parry Sound, July 21-28; Nipissing, July 14; Sudbury, July 12; Algoma, Aug. Genus GONIOPS Aldrich Goniops chrysocoma (Osten Sacken) Stout species (12 mm.) ; yellowish; wings with a dark pattern. Male brownish; abdominal tergites with pale bands on the hind margins. Ontario Records —Lincoln. 84 Genus MERYCOMYIA Hine Merycomyia whitneyi (Johnson) Large (21 mm.) ; brownish; abdomen with a large white patch indented above on the fourth tergite and 2 white spots on the fifth tergite; wing membrane tinted with brown which is deeper towards the front margin and.base and along the veins; costal cell yellowish brown. Ontario Records—Wentworth, Aug. 4. 10. Genus CHRYSOPS Meigen Key to the Species of Ontario Chrysops—Females moApex of wine beyond the crossband hyaline..............00..2..4.000.0 2 Apex of wing beyond the crossband infuscated so that an apical spot WS. SOUS RYO TON TSE a a a ts nae ee ae a a ore DUS SEM ea aL a a 10 Second basal cell hyaline; frontoclypeus without median pollinose STEVETIOE. gL Soe eH PS EURO CO Re CA ge a eR Ve ve een ta db a eR niger Macq. Second basal cell at least half infuscated ; frontoclypeus with a median FV GuLINT OSS See BOL Sie ce ui etna ne = Sau N ee ceria) Uae nadh ibtaget Tans ee ae Abdomen entirely dark; sometimes an indefinite pattern of grayish POUT OSS: Ce VaNS) ONG See SS eR eta A a a ce ens ON eee Maarten eter eee 4 Abdomen with pale areas on at least first 2 abdominal segments ..... 7 Hien posterior cell. with hyaline area. at base... oo)... 5 Punemestenion cellintuscated at base). 2.0). 0c. cee i 6 Outer margin of crossband relatively straight, often reaching hind margin of wing; hyaline area at base of fifth posterior cell very distinct; apex of wing completely clear...................... carbonarius Wk. Outer margin of crossband irregular, rarely reaching hind margin of wing; hyaline area in fifth posterior cell sometimes obscure; apex of wing often with a vague infuscation....carbonarius nubiapex Philip Pleura with yellow to orange-red pile; crossband broadly reaches Meme In Ol WING 23 eA es cincticornis WI1k. Pleura with grayish or pale yellowish pile; crossband narrowly or not aieclleneachine hind marein Of WINS. 60.4.0. mitis O.S. Tergites with gray posterior borders; infuscation of second basal cell much less than first; apical portion of wing sometimes faintly infus- Ree Ge ey AN rn oy en RN on sordidus O.S. Tergites without gray posterior borders; infuscation of basal cells OO Ue GUC tie ere a nA ka ae Se ee 8 Wing picture pale; pleura with gray or grayish yellow pile; lateral pale area on abdomen grayish yellow ...............00...0...00..... cuclux Whitn. Wing picture dark; pleura with yellow to orange pile; lateral pale abea yellow tovorange. often extensive oe. ees 9 Median abdominal triangles absent; outer margin of crossband relatively regular; upper margin of frontal callus usually straight .... eet ON Oa aah eel ela a NN ag dawsont Philip Median abdominal triangles present; outer margin of crossband irregular; upper margin of frontal callus somewhat pointed in centre er re ye ee er eA Pate NORGE Ut ON ile 8 excitans Wk. Frontoclypeus black with a median pollinose stripe ........................ oil Frontoclypeus shining yellow at least in centre; no median pollinose SUFIDG. te ee Pe Cae cesta Oe en ke: Nn be Pegi 8 Noo et BT 12. 13. 14. 15. 16. gaye) 18. 19: 20. 7d 22. 23. Apical spot paler than crossband with indefinite outline; dark species with paie borders and small triangles on abdominal segments: first 2 abdominal segments with small reddish lateral markings sordidus O.S. Not with above combination of characters-. 2). ee 3 be? Completely black species; hyaline triangle crosses ebeces longitudinal VEL: oe Sade: Oe ace eae 2 Re pee ea noctiferus pertinax Will. Not completely black species; hyaline triangle does not cross second longitudinal. veln’ 40°25)? ee ee Blackish species with small pale spots laterally on first 2 tergites and narrow pale posterior bands which expand into small median tri- angles; a projection from the crossband reaches bifureation of third longitudinal Veins 3.053 eee ee ee eee nigripes Zett. Often bright yellow and black species; if blackish, crossband does not. reach: bifurcation. 24.32 ee ee Le eee 14 Tergites with bright yellow posterior bands which do not expand to divide black anterior portion of tergites; hind tibia always black .... oD ABR Dees BAUR ON 6. aR iias eine aan te Sa ae venus Philip Yellow abdominal markings, if present, divide black on tergites into spots not reaching lateral margins; hind tibia black to yellow ............ ee Ee are eee ne ae Se eM frigidus O.S. Crossband and apical spot broken by dilute areas along veins; abdomen Strate 2. > Soe ol cay 9 ag ie ee eee rt ee oo eee shermani Hine Dark markings of wings not broken by dilute areas ........................ 16 Wing pattern dilute; abdomen yellow with 4 black stripes of which sublateral ones are narrow and begin on second tergite; apical spot HATTO Wi |. OER a ea aL aces Seek ee ea luteopennis Philip Not with this combination of characters —....)...0 23 17 Apical spot dilutely extended around wing reducing hyaline triangle to a subhyaline area not reaching hind margin of wing; large brown species with swollen first antennal segment and little or no trace of abdominal markings 500.0 ee brunneus Hine Not with above.combination of characters ...2...2\...2)) 22 ee 18 First basal cell completely infuscated, rarely with a subhyaline spot AL ADC. is se ee ier Se 19 First basal cell always at least half hyaline, sometimes almost entirely SOU ee ee ee a a Se aed a Hyaline triangle small but clear and distinct, restricted to apices of second, and third: posterior-cells: 244 Oe ee moechus O.S. Hyaline triangle extending toward costal margin of wing beyond second. posterior cell 2.2 ee eee 20 Predominantly fuscous species with pale abdominal markings con- sisting of a pale median line and occasionally with traces of lateral TCS se ES NS Cote aN ore ie ea re dacne Philip Abdomen conspicuously marked in yellow and black: 2a 2 Apex of hyaline triangle reaches second longitudinal vein .................... piket Whitn. Apex of hyaline triangle not reaching second longitudinal vein... 22 Abdomen with 4 more or less complete dark longitudinal ae 23 Abdomen not striped or with less than 4 stripes ........................... 25 Most of fifth posterior cell infuscated; scutellum yellow ...................... vittatus Wied. Fifth posterior cell almost entirely hyaline; scutellum dark, with or without. palertapex? | 22) a ee ee 24 24. 25. 26. 27. 28. 29. 30. dl. o2. Apical spot nearly fills second submarginal cell; 2 central stripes of abdomen rarely joined on second segment; frontal callus yellow, TED CEU AACE WE ca co OY Martane VO CAA Ue denn RU Sa San aberrans Philip Apical spot only about half fills second submarginal cell; 2 central abdominal stripes usually join on second segment; frontal callus usually black, sometimes brownish, rarely yellowish. ....... striatus O.S. Apical spot fills out most of second submarginal cell and extends into first and sometimes second posterior cell, usually connecting with crossband by an infuscated streak in the first posterior cell; abdomen with 2 stripes which are sometimes reduced to faint lines or enlarged to cover much of abdomen on each side of a central yellow stripe; scutellum usually with considerable yellow ................ macquartt Philip Apical spot fills only about half of second submarginal cell and does not extend further; abdomen not striped; scutellum dark... indus O.S. Apical spot narrow including at most only extreme apex of second Molnar eOdMMel sCel iy soe sce ah wk eerck Ti Psat, AE ng a Bt ek VE Apical spot broad, entering second submarginal cell over at least one rMGeor Upper, branch of third longitudinal vein) (3.00... a Apical spot just beyond where it leaves the crossband slightly wider than marginal cell; frontal callus usually yellow, often bordered with Higcwombrowm, occasionally black 24.0800 ae 28 Apical spot at base narrower or just as wide as marginal cell; frontal MMO SMIN OLACACEAE a 2 Black spot on second abdominal segment practically joins with that on first segment; second and third sternites with black sublateral SOUS GODUSL ISDECLOS he te ome boi Me ee A Rie sackent Hine Black spot on second segment usually does not attain the anterior margin; no sublateral spots on sternites; more slender species ........ seis ceca NOTIN TUES OM ad SA GTR a tee yt aN ade Ue Gt eee me Teng Oat ORE pudicus O.S. Crossband dilute and leaving about half of discal cell hyaline; cheeks black; frontoclypeus with large black spot on each side ........................ ee rec he CaN Rea NG Ga Mee Uk clad delicatulus O.S. Crossband saturate and covering discal cell; frontoclypeus and cheeks MeNOnVetO OLA ei uv er Ne ee et ee tae ne Apical spot very narrow and more dilute than crossband; front little convergent at vertex; pale markings of abdomen usually grayish or dull yellow; on the second abdominal segment are black triangles, one on each side of the dark median marking, and they may or may not be connected with the latter by a dark band along the posterior margin OUREME SOC TICTMN ey oe he a ea rey ol og Males aestuans Wulp Apical spot varies from one half to full width of marginal cell and is Same density as crossband; front somewhat convergent at vertex; pale markings of abdomen yellow which is sometimes quite bright; dark median marking of second abdominal segment may have projec- tions along posterior margin of segment but they do not form lateral PEP NOS) UN Cee tae As Cr ke tg callidus O.S. Blackish species with a mid-dorsal yellow (rarely grayish) abdominal stripe, sometimes with shorter stripes on each side... wnivittatus Macq. Abdomen with a different pattern and showing more yellow ........ 32 Hyaline triangle distinctly crosses second longitudinal vein nearly BeDAn AINE apical SOL from: CLOSSWANIC uli M2 ie ys ha 33 Hyaline triangle at. most reaches second longitudinal vein 87 33. 3A. 35. 36. oT. 38. 39. First and second basal cells are almost condplerely hyaline 4.332 35 Abdomen with a somewhat crescent shaped median black spot on the second tergite which is often constricted where it joins black spot on first tergite; no other spots on second tergite; fore coxa usually mostly Weellow ec Ss en eee dere) Georg ne ead furcatus WIk. Second tergit with a heavier median black spot not usually constricted at its juncture with the spot on the first tergite; 2 small isolated black spots on each side of median spot; fore coxa all or mostly dark eM es Grr meee ee Ori OM imc eeu SS furcatus chagnoni Philip Apical spot occupies only about half of second submarginal cell; cross- band usually does not reach hind margin of wing ...... lateralis Wied. Apical spot occupies almost all of second submarginal cell; crossband reaches hind margin of-wint’ -...5. 23. See 36 Second tergite with a black median marking of 2 dark spots which may be separated or joined anteriorly........................ geminatus Wied. Second tergite completely yellow.................. geminatus impunctus Krb. Abdomen with 4 rows of spots, but lateral spots on second tergite may be reduced or absent; median figure on second tergite an inverted “V”; scutellum and frontal callus normally dark but latter sometimes VOW IIS eet See ree montanus O.S. Abdomen normally not with 4 rows of spots... eee 38 Hyaline triangle does not reach second longitudinal vein; pale yellow- ish species with yellow brown thorax and obscure body ‘pattern ed Wee re oN OCU IN inet PE IRE gE rks Ma tants flavidus Wied. Hyaline triangle reaches second longitudinal vein; yellowish and black species with dark thorax and distinct body pattern Ps Saga 39 Abdomen with sublateral black spots on second tergite ......................... MUN pL. (Ti runtime gee eae SAAS a phe MR RUE cen ee) aestuans abaestuans Philip Second tergite without sublateral spots............00...0....00.. pudicus O.S. Key to the Species of Ontario Chrysops—Males Apex of the wing beyond the crossband hyaline, sometimes a vague cloud present in this areas.20) 2000 i 2 Apex of wing infuscated beyond the crossband so that an apical spot is PrESeNnb oN eee Se ee ae Se ae er 9 Frontoclypeus yellow with a large black spot on each side; no midfacial pollinose ‘stripe. 74 ie ee ee niger Macq. Frontoclypeus black with a midfacial pollinose stripe which begins below antennae and runs at least half way to oral margin ............ 3 Abdomen. completely. black <1..0.40055. 222 First 2 abdominal segments with small reddish or yellowish spots laterally 2302 eee oe EE eo es Fifth posterior cell with a.hyaline area at base 2.2... oan 5 Fifth posterior cell infuscated at base..24. tics. 6 Outer margin of crossband straight, usually reaching hind margin of wing ; hyaline spot at base of fifth posterior cell very distinct; apex of wing clear no ato ee ees Oleh ee ce ern aa carbonarius Wilk. Outer margin of crossband irregular, narrowly or not at all reaching hind margin of wing; hyaline spot at base of fifth posterior cell some- times obscure; apex of wing with an indistinctly outlined apical spot def lube piste ad 3) Tg Seis Me ten a aI mes ea carbonarius nubiapex Philip 14. 15. 16. 17. 18. ND) Crossband broadly and distinctly reaches hind margin of wing; outer margin of crossband usually very straight .............. cincticorms Wlk. Crossband narrowly, indistinctly or not at all reaching hind margin of wing; outer margin of crossband usually irregular ............ mitis O.S. NVaMon malvern OUMUILe sf Sk Se ai Be ee ene cuclux Whitn. NV OMOn Me LeI Carwin. iis 8 ize et ee 8 Crossband reaches or almost reaches hind margin of wing, outer margin regular; no median abdominal triangles ........ dawson Philip Crossband abbreviated, outer margin irregular; median abdominal imiancles may or may not be present 0.02.0. 233! excitans Wk. Frontoclypeus with a midfacial pollinose stripe which begins below antennae and runs at least half way to oral margin; integument of mOnLOclypeus: Usually entirely black 2-37.80 10 Frontoclypeus without a midfacial pollinose stripe; integument at eNom lta WOU OW ee th Cnc eer Se ee a tenes L5 Crossband with a projection reaching bifurcation of third longitudinal WOMTE © ceca ah fe 8 A Sh RR OUI a ea ea Ieee II ai nigripes Zett. Momsuch projection. trom c¢rossband ) 2.002 ee i 11 meNogomen- completely black. s:0s.20.2.00 ele el 12 Paaomen mov completely, black 2.0.0.0 13 . Apical spot rather indeinite in outline... carbonarius nubiapex Philip Apical spot rather sharply defined.................. noctiferus pertinax Will. . Black species with pale abdominal markings restricted to sides of first 2 segments and traces of small median and posterior markings; lesseimosh entirely, dark: 2s bot A sordidus O.S. Species usually with considerable yellow on abdomen; legs often with HTC MERION ON, eee he ee Ue ee 14 Third to fifth abdominal tergites with a parallel-sided black band along anterior margin of segment and a similar yellow band along posterior marein : hind tibiae black 3004.50.00... venus Philip Abdomen not banded; hind tibiae often reddish ............... frigidus O.S. Abdomen black with no yellow markings; hyaline triangle restricted to apices of second and third posterior cells... moechus O.S. Abdomen not completely black; hyaline triangle more extensive 16 Crossband and apical spot broken by dilute areas along veins ............ nesta cco “mOeae ee GE TOES lets op UG Ale te cee ok eet RI TE shermani Hine Crossband and apical spot not broken by dilute areas although entire PGP unemM Mave De WAle 26) gee ON ee ae nid ee 17 Brownish species with swollen first antennal segment and with hyaline triangle respresented by a narrow hyaline or subhyaline area not ReACMMMNG, MIMO MINArolM Ok WANG). brunneus Hine iNotawitn this combination of characters 22...) 28.2000. Black species; abdomen with a yellowish median longitudinal stripe, occasionally with a similar abbreviated stripe on each side; hyaline triangle crosses second longitudinal vein; apical spot rarely occupies more than half of second submarginal cell, often less univittatus Macq. Not with above combination of characters ata tap htt en Seem Aen 19 Apical spot very little broader at its apex than at its origin, crossing upper branch of third longitudinal vein at its apex and occupying very lithe On the second submarginal-cell .= <%o.2 8. eee 20 Apical spot considerably broadened towards its apex, crossing at least half of upper branch of third longitudinal vein .................... 23 89 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. ol. Hyaline triangle not reaching second longitudinal vein .... sackeni Hine Hyaline triangle reaching or crossing second longitudinal vein... 21 Frontoclypeus with a large black spot on each side... delicatulus O.S. Frontoclypeus entirely yellow or, at most, with some dark shading around frontocly peal: pits: 2" ae ee ee eee Second abdominal segment with sublateral black triangles which join the median figure along the posterior border of the segment; fourth posterior cell usually hyaline at apex and fifth posterior cell with considerable infuscation especially basally; pale marking grayish yel- low; apical spot very. Marrows wee ey ees aestuans Wulp Second abdominal segment without sublateral black triangles; fourth posterior cell usually entirely infuscated and fifth posterior cell often mostly hyaline; pale markings yellow........................ callidus O.S. Abdomen bright yellow and black; large black figure of second ab- dominal segment broadly joined to black figure of first segment; median yellow triangles do not reach the anterior border of the ~ segments; apical spot occupying one half to two thirds of second submarignal’ cell SN ee ee A ee Not with above combination of characters... 3... 3 a 27 Frontoclypeus with a black spot on each side ............0....00... 25 Frontoclypeus entirely yellow 02.0. .40).25.. 2) 4 26 Second abdominal segment entirely yellow bers is eae furcatus Wlk. Second abdominal segment with sublateral black spots ...............0......... oT ee AA GEG INU AD ACNE GOI LS ge Oe aati sO gi furcatus chagnoni Philip Abdomen with a sublateral row of black spots; median yellow tri- angles moderate in size; hyaline triangle extending beyond bifurcation of third longitudinal vein, sometimes reaching second longitudinal WOT i SER RS LEG ae pie at dita A gee ree ane ee montanus O.S. Abdomen without a sublateral row of black spots; median triangles very small, sometimes obsolete; hyaline triangle ends at bifurcation of third lonsitudinal vein «(ie ee indus O.S. Apical spot filling about half or less of second submarginal cell... 28 Apical spot filling all or nearly all of second submarginal cell, some- times extending into first posterior cell (W031... 2 31 Frontoclypeus with a black spot on each side; hyaline triangle crosses second longitudinal wel: ooo ee a ee eee lateralis Wied. Frontoclypeus entirely yellow; hyaline triangle does not cross second longitudinal wweins 2. 80 ce es Oe es ae eee 29 Second basal cell mostly infuscated; abdomen with extensive black markings, which on second segment broadly reach anterior margin et et any Seer dune Re Satu radia ty EL oy asf aestuans abaestuans Philip Second basal cell mostly hyaline; abdomen mostly yellow with brown markings which may be ‘indistinct. 42.9. ee gett 30 Thorax brownish with brown stripes; yellowish species with some- what indistinct abdominal pattern; hind femora completely yellow Ee NCC rae eh A Lee Fe flavidus Wied. Thorax greenish gray with fuscous stripes; dark abdominal markings distinct; hind femora usually dark at base.......................... pudicus O.S. Hyaline triangle crosses second longitudinal vein; apical spot does not extend beyond second submarginal cell; yellow species with black median abdominal spots which are sometimes absent on second seg- 1 a\e1 ch eee rae Mine eR eM ED A cs alco RENAUD (pained oeeu gn cc. on Not with above combination of:characters 3.0.5 oie eee 33 90 32. 30. 34. 35. 36. 37. Second abdominal segment with black median spots which often are HOUMeC ea Mee KlOM YH ioe Sie Rc ee ee a tee geminatus Wied. Second abdominal segment without spots... geminatus impunctus Krb. Hyaline triangle reaches or nearly reaches second longitudinal vein Gf subhyaline above bifurcation of third longitudinal vein, pre- dominantly black species with pale abdominal markings reduced) 34 Hyaline triangle scarcely extends beyond bifurcation of third longi- tudinal vein; predominantly yellowish species with dark abdominal TUTTE RIAU GRY agers SARS Soe daar aa ere RT a tre Sb en NLL Oy at gh cos rea ee 35 Blackish species with reduced pale abdominal markings; hyaline tri- PoE IeO OUNCE: Ab AMEX er he sl a eee dacne Philip Yellow species with black abdominal markings; hyaline triangle iP OUUTETCIS GL REN 6 (eae ae re ae et es CA mee piker Whitn. Abdomen with a median yellow stripe with a longitudinal black band on each side; lateral margins of segments narrowly yellow ................ co sucing lke MARCOS IoC eel a Ale en RSM ny ree NOP ee macquarti Philip Abdomen yellow with 4 more or less complete rows of black spots 36 Ground celor of thorax and scutellum yellow.................... vittatus Wied. Ground color of thorax plumbeus; scutellum sometimes with some TRU ISIN Cele a a dA a le eae al mA ona UR ee 37 Apical spot completely fills second submarginal cell; the sublateral rows of abdominal spots are about as dark as the median rows .......... _ cnno's Suge SUSNGHG SCE AGL dale iy As Oat Sg NGG ge anges ee sea ne ere Cape aberrans Philip Apical spot not completely filling second submarginal cell; sublateral rows of abdominal spots paler than median rows.............. striatus O.S. Chrysops aberrans Philip Moderate in size (8 mm.) ; yellow and black; thorax greenish in ground color; black stripes on abdomen, the median pair rarely joining on the second tergite; first basal cell wholly infuscated ; fifth posterior cell mostly hyaline; apical spot broad, usually nearly filling second submarginal cell; frontal callus yellow, Male with yellow areas reduced; second basal cell largely infuscated. Ontario Records—Essex, Aug. 5; Kent, July 10-18; Middlesex, July 17-20; Norfolk, July 14; Welland, July 17; Wentworth, June 29-Sept. 3; Waterloo, July 21; Wellington, Aug. 1; York; Bruce, July 20; Simcoe, July 28; Victoria, July 4; Peterborough, July; Hastings, July 16-Aug. 16; Prince Edward; Lennox and Addington, Aug. 13-18; Frontenac, Aug. 10; Leeds, Aug. 6; Carleton, July 7-Aug. 12; Renfrew, July-Aug. 2; Haliburton, Sept. 11; Muskoka, July 4-Aug. 22; Parry Sound, July 10-29; Nipissing, July 15-Aug. 15; Algoma, Aug. Chrysops aestuans Van der Wulp Moderate in size (8.5 mm.) ; black; abdomen with gray or yellow- ish gray markings not in form of stripes; both basal cells hyaline; apical spot very narrow; crossband often not reaching hind margin of wing. Male generally darker; both basal cells partly infuscated. Ontario Records—Essex, June 5-Aug. 5; Kent, July 16; Lambton, July 17; Norfolk, June 27; Welland, July-Aug. 6; Wentworth, Aug. 5-18; Waterloo, July 2; Wellington, June 24-July 28; York, June 22; Simcoe, July 28; Durham, Aug. 25; Victoria, July 4; Peterborough, Aug. 8; Prince Edward; Hastings, June 12-Aug. 2; Lennox and Addington, 91 June 29-Aug 21; Frontenac, Aug. 7; Leeds, July 9; Carleton, July 8; Muskoka, July 24-Aug. 27; Nipissing, July 15-Aug. 16; Parry Sound, July 12-26; Manitoulin; Algoma, June. Chrysops brunneus Hine Rather large (9 mm.) ; brown; abdominal pattern obsolete, some- times with dark shadows and with faint pale median triangles; the broad apical spot continues around the wing and joins the crossband by a lightly infuscated area along the hind margin | isolating the hyaline triangle; both basal cells partly infuscated ; first antennal segment swollen. Male differs from female only in sex characters. Ontario Records — Essex, June 22-Aug.; Kent, July 18; Lambton, July 16; Norfolk, July 14; Lincoln, July. 16. . Chrysops callidus Osten Sacken Moderate in size (8 mm.) ; black and yellow; abdominal markings not in form of stripes; both basal cells hyaline; apical spot nar- row; crossband reaching hind margin of wing. Male with pale markings less extensive; both basal cells partly infuscated. Ontario Records — Essex, June 5-July 24; Kent, July 16; Lambton, June 11-July 17; Middlesex, July 3; Norfolk, June 23; Welland, July 16- Aug. 4; Lincoln, July 9-26; Wentworth, June 15-Sept. 2; Halton, July 2; Waterloo, July 2-19; Wellington, June 24-July 12; Dufferin, July 15; Grey; Durham; Peterborough, July 4; Hastings, July 3; Leeds, June 25-July 10; Carleton, June 26; Renfrew, July 14; Muskoka, July i: Parry Sound. Chrysops carbonarius Walker Moderate in size (8 mm.) ; black; fifth posterior cell with clearly defined hyaline spot at base; apical and anal area of wing hy- aline; outer margin of crossband straight. Male with both basal cells at least three quarters infuscated; no trace of apical spot; outer margin of crossband straight. Ontario Records — Kent, June 4; Elgin, June 4; Middlesex, June; Norfolk, June 18; Brant, June 30; Wentworth, May 25-June 26; Waterloo, May 23; Wellington, May 29-July 4; Peel, June 3-9; Bruce, June 11; Grey, June 15-18; Dufferin, June 12; York, June 8; Simcoe, June 3-28; Victoria, July 24; Hastings, May 28-July 2; Carleton, May 28-June 18; Renfrew, June 22; Nipissing, June 10-July 8; Muskoka, June 23; Parry Sound, June 18-21; Sudbury, June 6-July 10; Algoma, June 1-Aug.; Timiskaming, June 26-July 10; Cochrane, June 12-July 19; Thunder Bay, June 1-July 17; Patricia, June 27. Chrysops carbonarius nubiapex Philip Moderate in size (8 mm.) ; black; fifth posterior cell hyaline at base but spot sometimes poorly defined; often some vague in- fuscation in apical and anal areas of wing; outer margin of cross- band irregular and/or bowed outwardly. Male with both basal cells at least three quarters infuscated; wing with apical spot but with margins poorly defined; outer margin of crossband irregular. Ontario Records — Norfolk, May; Wentworth, June 2-18; Wellington, June 17; Peel, June 9; York, June 8; Timiskaming, June 26-July; Algoma, June 24; Cochrane, June 28-July 9; Thunder Bay, June 21-July 24. 92 Chrysops cincticornis Walker (= celer O.S.) Rather large (9 mm.); black; pleura with dense yellow to orange-red pile; fifth posterior cell infuscated at base; both basal cells more than half infuscated; no apical spot. Male lacks the orange pleural pile of the female; anal area of wing dilutely in- fuscated. Ontario Records — Essex, June 19; Lambton, June 12; Middlesex, June 8; Elgin, June 4-25; Norfolk, June 1-Aug, 27; Lincoln, May-June 25; Wentworth, May 238-July 16; Wellington, June 16-27; Grey, June 18; York, June 20-26; Simcoe, June 9-July 3; Muskoka, June 26-July 30; Peterborough, July 4; Hastings, June 21-July 7; Frontenac, July 18; Leeds, June 25-July 7; Carleton, June 11-Aug. 18; Renfrew, June 22; Haliburton; Parry Sound, June 28-July 28; Nipissing, June 6-Aug. 1; Sudbury, July 11. Chrysops cuclux Whitney Moderate in size (8 mm.) ; black; abdomen with a grayish yellow area laterally near base; wing pattern pale; both basal cells more than half infuscated; no apical spot. Male with pale area of abdomen smaller than in female. Ontario Records — Elgin, May 16; Oxford, June 4; Norfolk, June 1; Wentworth, June 6-13; Wellington, June 4-July 3; Peel, June 1-5; York, May-June 12; Simcoe, July 4; Hastings; Leeds, July 7; Carleton, May 31-June 7; Nipissing, June 2-July 29; Parry Sound, June 27-July 22; Manitoulin; Sudbury, June 23; Algoma, June-July 11; Timiskaming, June 26-July 9. Chrysops dawsoni Philip Moderate in size (8 mm.); black; abdomen with a yellow area laterally near base but no median triangles; fifth posterior cell somewhat paler at base; outer margin of crossband quite regular; no apical spot. Male darker than female with pale abdominal markings reduced. Ontario Records — Bruce, July 10; Timiskaming, June 26; Cochrane, June 16-Aug, 12; Thunder Bay, June 18-July 20; Patricia, July 7-15. Chrysops delicatulus Osten Sacken Moderate in size (7.5 mm.); black and pale yellow; abdominal markings not in form cf stripes; both basal cells hyaline, discal cell partly hyaline; frontoclypeus with a black spot on each side; apical spot narrow. Male with both basal cells partly infuscated. Ontario Records — Muskoka, July 22-Aug. 12; Parry Sound, July 7-30. Chrysops excitans Walker Large in size (10 mm.); black; abdomen with a yellow area laterally near base and median triangles on second, third and fourth tergites; pleura with dense yellowish pile; fifth posterior cell infuscated at base; outer margin of crossband irregular; no apical spot. Male darker than female with pale abdominal mark- ings reduced, sometimes obsolete. Ontario Records — Waterloo, June 19; Wellington, June 22; Bruce, June 13-July 10; Simcoe, June 9-July 2; Victoria, June 27-July 4; Peter- borough, July 3; Leeds, June 25-July 7; Renfrew, June 24; Hali- 93 burton, June 12; Muskoka, June 5-July 12; Parry Sound, June 18-July 28; Nipissing, May 28-Aug. 14; Sudbury, June 19-Aug, 20; Mani- toulin, June 16; Algoma, June 9-Aug. 10; Timiskaming, July 5-Aug. 1; Cochrane, June 14-July 26; Thunder Bay, June 14-July 20; Kenora, June 22-July 22; Patricia, June 15-July 15. Chrysops frigidus Osten Sacken Moderate in size (7.5 mm.); black and orange; extent of color pattern of abdomen variable, sometimes almost completely black or almost completely orange yellow but pattern never in form of longitudinal stripes; frontoclypeus with a median pollinose stripe; both basal cells partly infuscated; apical spot broad and broadly united with crossband. Male wtih infuscation in both basal cells greater than in female. Ontario Records — Middlesex, July 4; Wentworth, May 4-July 30; Water- loo, June; Wellington, June 17-July 28; York, July; Simcoe, June 29-July 22; Victoria, June 26; Hastings, June 22-July 13; Grenville, June 5-July 4; Carleton, June 5-July 30; Renfrew, July 4; Haliburton, Aug. 20; Muskoka, June 19-July 29; Nipissing, June 10-Aug. 11; Parry Sound, June 18-Aug. 27; Timiskaming, July 10; Sudbury, July 11-20; Algoma, June 21-July 2; Cochrane, June 2-July 22; Thunder Bay, June 21-July 31. Chrysops furcatus Walker Fairly large (9 mm.) ; yellow and black; first basal cell about half infuscated; hyaline triangle crosses second longitudinal vein; black median spot on second tergite not accompanied by sublateral spots. Male readily associated with female; both basal cells more than half infuscated. Ontario Records — Nipissing, June 21; Cochrane, July 11l-Aug. 15; Thunder Bay, July 1-20; Patricia, July 13. Chrysops furcatus chagnoni Philip Moderate in size (8.5 mm.) ; differs from typical form in presence of sublateral spots on second tergite, only slight contraction of median spot on second tergite where it joins spot on first tergite and darker front coxae. Male differs from female only in usual sex characters. Ontario Records — Cochrane, June 27- July; Thunder Bay, June 30-July 3. Chrysops geminatus Wiedemann Small to moderate in size (7 mm.) ; black and yellow; abdominal markings usually not in form of stripes but black markings occa sionally reduced and appear as broken rows of spots; both basal cells hyaline; apical spot broad and nearly separated from cross- band. Male with some dilute infuscation in both basal cells. Ontario Records — Elgin, July 18; Middlesex, July 17; Norfolk, July 11-Aug. 13; Wentworth, June 29-July 28; Waterloo, July 24-31; Wellington, Aug. 1; Grey, July; York, July 27. Chrysops geminatus impunctus Krober Like typical form but lacks spots on second tergite. Ontario Records — Elgin, June 25; Wellington; Carleton. 94 Chrysops indus Osten Sacken Moderate in size (8 mm.) ; yellow and black; abdomen with a row of rather large yellow median triangles; hind margins of tergites narrowly and lateral margins broadly yellow; first basal cell infuscated; apical spot broad; frontal callus black. Male with black areas much more extensive than in female; both basal cells and fifth posterior cell almost completely infuscated. Ontario Records — Essex, June 9-11; Kent, July 20; Elgin, May 25; Middlesex, May 29-June 30; Norfolk, June 1-July 11; Lincoln, May 31-July 14; Wentworth, May 29-July 18; Brant, Aug. 15; Waterloo, June 14-July 12; Wellington, May 30-July 28; Halton, June 9-July 2; Peel, June 8-25; York, May-June 24; Bruce, June 18-24; Simcoe; Hastings, June 20; Lennox and Addington, June 29; Leeds, July 7-25; Carleton, June 7-25; Renfrew, July; Muskoka, June 26-July 28; Parry Sound, June 27-July 28; Nipissing, June 3-Aug. 11; Sudbury; Algoma, June 9-Aug. Chrysops lateralis Wiedemann Moderate in size (8 mm.); yellow and black; abdomen with a yellow median stripe, usually black laterally but sometimes black reduced to form rows of spots; both basal cells hyaline; apical spot broad and nearly separated from crossband. Male with some dilute infuscation in both basal cells. Ontario Records — Wellington, July 14-Aug. 5; Simcoe, July 7-22; Hast- ings, June 10-July 12; Muskoka, June 26-July 21; Parry Sound, July 8-25; Nipissing, June 30-Aug. 4; Algoma, Aug. Chrysops macquartt Philip (= univattata of authors, not Macquart) Moderate in size (7.5 mm.); yellow and black; thorax greenish gray in ground color; abdomen with yellow median stripe between 2 black stripes of varying width, laterally yellow; first basal cell infuscated ; fifth posterior cell mostly hyaline; apical spot very broad; hyaline triangle small and irregular in outline; frontal callus black or dark brown. Male with broader black abdominal stripes; second basal cell half or more infuscated. Ontario Records — Essex, June 2; Norfolk, June 24; Welland, June 28; Wellington, June 24-Aug. 27; Halton, July 2 Chrysops mitis Osten Sacken Large (9.5 mm.) ; black; fifth posterior cell infuscated at base; no apical spot; both basal cells more than half infuscated. Male with considerable dilute infuscation in anal area of wing. Ontario Records — Essex; Norfolk, June 27; Oxford, June 4; Lincoln, June 20; Wellington, May 27-July 14; Halton, June 10; Bruce, June 18-23; Dufferin, June 12; Simcoe, June 9; York, June 12; Victoria, June 27; Hastings, June 7-25; Carleton, May 19-June 12; Muskoka, June 4-21; Parry Sound, June 21-July 9; Nipissing, May 28-July 10; Manitoulin; Timiskaming, June 26; Cochrane, June 27-July 17; Thunder Bay, June 5-Aug. 5; Kenora, July 22; Patricia, June 20-July 16. Chrysops moechus Osten Sacken Moderate in size (7.5 mm.) ; yellow and black; thorax greenish in ground color; black markings of abdomen usually in form of 95 stripes; first basal cell infuscated; fifth posterior cell mostly hyaline; apical spot very broad; hyaline triangle extremely small but regular in outline; frontal callus usually black. Male black; wings almost entirely infuscated except for small hyaline triangle. Ontario Records — Wentworth, July 3-5; Waterloo, July 2; Wellington, June; Simcoe, July 3; Muskoka, July 26: Grenville, Aug. 10: Carleton, July 10. Chrysops montanus Osten Sacken Moderate in size (8 mm.); black and yellow; abdomen with a geminate black spot and often with a sublateral black spot on the second tergite, and 4 rows of spots on the third, fourth and fifth tergites; first basal cell partly infuscated, second nearly hyaline; apical spot variable but usually broad. Male with yellow areas usually much reduced; both basal cells partly infuscated. Ontario Records — Huron, July 7-17; Welland, July 31; Lincoln, June 28-Aug. 16; York, June 27-July 14; Dufferin, July 15; Simcoe, July 22; Hastings, June 25-Aug. 12; Frontenac, July 18; Leeds, June 25-July 24; Lanark, Aug. 2; Carleton, June 30-July 2; Renfrew, July 23; Nipissing, June 16-Aug. 20; Muskoka, June 21-Aug. 12; Parry Sound, June 27-July 31; Manitoulin; Algoma, June 21-Aug.; Kenora, July 25. Chrysops niger Macquart Moderate in size (7.5 mm.); black; first basal cell infuscated, second hyaline; no apical spot. Male wing with both basal cells largely infuscated. Ontario Records — Elgin, June 4; Middlesex, June 14-July 5; Lincoln; Wentworth, June 15-July 6; Waterloo, May-June; Wellington, June 6-July 22; Halton, June 9; Peel, June 8; Bruce, July 20; Simcoe, June 28; Hastings, June 21-July 6; Carleton, June 2-July 11; Renfrew, June 22; Muskoka, July 2-7; Parry Sound, July 8; Nipissing, June 4-July 30; Timiskaming, July 5-8; Sudbury, June 30-July 11; Algoma, June-July 23; Thunder Bay, June 21-July 9. *Chrysops nigripes Zetterstedt Moderate in size (8 mm.) ; blackish, abdomen with pale sublateral markings near base, median triangles and narrow incisures; crossband with projection which rather broadly reaches bifurca- tion of third longitudinal vein; frontcclypeus with a median pollinose stripe. Male much like female but darker and basal cells more extensively infuscated. Ontario Records — Patricia, July 20-24. Chrysops notiferus pertinax Williston Rather large (9 mm.); abdomen completely black; hyaline tri- angle crosses third longitudinal vein, practically separating apical spot from crossband; frontoclypeus with a median pollinose stripe. Male black; infuscation of basal cells somewhat more ex- ane than in female; base of fifth posterior cell often partly yaline. Ontario distribution unknown. Reported from the province by Philip (1947) but since there are no records east of Alberta its presence in the province is questionable. 96 Chrysops pikei Whitney Rather small (7 mm.) ; yellow and black; thorax greenish yellow in ground color; abdomen with black stripes, the sublateral ones quite short; first basal cell infuscated; fifth posterior cell mostly hyaline; apical spot broad; hyaline triangle rounded above; frontal callus black. Male with second basal cell partly infuscated. Ontario Records — Kent, July 20; Lambton, June 11; Wentworth, July 17. Chrysops sackent Hine Moderate in size (8.5 mm.); black and yellowish; abdominal marking not in form of stripes; both basal cells hyaline; apical spot narrow but at its origin slightly wider than marginal cell. Male usually with pale markings less extensive; both basal cells partly infuscated. Ontario Records — Essex, June 10; Kent; Middlesex, July 3; Haldimand, July 17; Lincoln; Wentworth, June 22; Waterloo, June 14; Welling- ton, June 22-July 8; York, July 9; Simcoe, July 11; Victoria, June 27-July 4; Peterborough, July 5; Hastings, June 2-July 26; Leeds, June 25-July 9; Carleton, June 19-July 11; Muskoka, June 18-July 28; Haliburton; Parry Sound, June 25-July 24; Algoma, June-July; Thunder Bay, July 9. Chrysops shermant Hine Rather large (9 mm.); yellow and black; abdominal pattern usually in form of stripes on a yellow background but there is a tendency for stripes to unite reducing yellow to a narrow median stripe and sublateral patches; wing pattern interrupted by hy- aline areas along veins. Male differs from female only in sex char- acters. Ontario Records — Peterborough, July 4; Renfrew, June 24-July 30; Nipissing, June 4-Aug. 17; Parry Sound, July 22; Sudbury, July 11; Manitoulin, Aug.; Algoma, June 10-July; Timiskaming, July 10. Chrysops sordidus Osten Sacken Moderate in size (8.5 mm.); black; abdomen with small pale median triangles; tergites with narrow pale hind margins and a pale area laterally on the second or first and second; first basal cell about one half and second about one sixth infuscated; apical spot absent or present as an indefinite dark area. Male much darker; both basal cells almost entirely infuscated; apical spot more distinct than in female. - Ontario Records—Parry Sound, June 20; Nipissing, June 3-28; Sudbury, July 1; Algoma, June 10-July 12; Cochrane, July 6-11. Chrysops striatus Osten Sacken Moderate in size (8 mm.) ; yellow and black; thorax greenish in ground color; black stripes on abdomen, the median pair usually united on second tergite; first basal cell infuscated ; fifth posterior cell mostly hyaline; apical spot broad but usually only about half filling second submarginal cell; frontal callus usually black or brown. Male with yellow areas reduced; second basal cell largely infuscated. Ontario Records — Essex, June 16-Aug. 7; Kent, June 21-Aug. 6; Middle- sex, June-July 3; Huron, July 13; Norfolk, June 15-Aug. 13; Went- worth, July 11; Waterloo, June 19-July 21; Peel, June 27; York, June 9% 12-July 22; Simcoe, June 21-Aug. 5; Victoria, July 4; Peterborough, July 5; Hastings, July 10-Aug. 12; Frontenac, July; Leeds, July 7; Carleton, July 6; Renfrew, July 23-27; Nipissing, July 13-Aug.; Mus- koka, June 26-Aug. 3; Parry Sound, July 20-25; Kenora, July 25. Chrysops univattatus Macquart (= wiedemanni Krober, not univittata of authors) Rather small (7 mm.) ; black or dark brown; abdomen with a median yellowish stripe and sometimes similar shorter sublateral stripes; both basal cells hyaline; apical spot broad and nearly separated from crossband. Male with first basal cell infuscated. Ontario Records — Essex, June 19; Elgin; Norfolk, June 15-July 27; Huron, July 10; Lincoln, June 20-July 26; Wentworth, July 4-Aug. 9; Waterloo, July 2; Wellington, June 24-Sept. 18; York, Aug. 8; Grey, July 9; Simcoe, July 20-Aug. 12; Ontario, Aug. 1; Victoria, July 4; Peterborough, July 5-16; Hastings, July 7-Aug. 16; Frontenac, Aug. 19; Grenville, July 27; Carleton, June 28-July 19; Renfrew, July 14- ‘Aug. 4; Nipissing, June 2.8- Sept. 18; Muskoka, July 3- Aug. Zor Parry Sound, July 18-30; Sudbury, J uly 23. Chrysops venus Philip Rather large (9 mm.) ; abdomen with a black and yellow banded appearance; both basal cells partly infuscated; hind tibiae com- pletely black; frontoclypeus with a median pollinose stripe. Male readily associated with female; median black area on second tergite heavier than in female and basal cells somewhat more extensively infuscated. Ontario Records — Muskoka, June 26-July 28; Hastings, July 6-19; Frontenac, Aug. 7; Nipissing, June 16-Aug. 17; Parry Sound, July 8-Aug. 27; Manitoulin; Timiskaming, July 10; Cochrane, July PaAwe. 17. Chrysops vittatus Wiedemann Moderate in size (8 mm.); yellow and black; thorax yellow in ground color; black stripes on abdomen; first basal cell infus- cated; fifth posterior cell largely infuscated : apical spot broad; frontal callus yellow. Male with yellow areas reduced; second basal cell largely infuscated. Ontario Records—Essex, July 1; Kent, July 20; Middlesex, June-Aug. Oo: Norfolk, June 20-July 27; Welland, July 16: Lincoln, a une 1-July 22; Wentworth, June 24-Sept. 73 Waterloo, June-Aug. 18; Wellington, June 16-Aug. 22; Peel, July 30; York, June 20; Grey, July; Simcoe, July 3-Aug. 13; Ontario, July 16-Aug. 1; Victoria, July 4; Hastings, June 22-Aug. 12; Prince Edward; Lennox and Addington, Aug. 13; Frontenac, July 18-Aug. 10; Leeds, June 25-Aug. 6; Grenville, July 3-27; Carleton, June 2-Aug. 14; Renfrew, Aug.; Nipissing, June 1-Aug. 18; Muskoka, July 13-Aug. 24; Parry Sound, June 27-Aug. 30; Sudbury, July 11; Algoma, June-Aug. Genus HAEHMATOPOTA Meigen Haematopota americana Osten Sacken Length 10 mm. Frons broader than high, wider below; wing with pale maculations; tibiae with pale rings. Male with wing mark- ings as in female; eyes heavily pilose; eye facets differentiated. 98 Ontario Records — Timiskaming, June 26; Cochrane, June 26-Aug. 18; Thunder Bay. Genus ATYLOTUS Osten Sacken Key to the Species of Ontario Atylotus 1. Pleural hairs yellow; basal portion of third antennal segment about PE ePEOTO AS IOUO et ay oar on aR, OT be eee bicolor (Wied). Pleural hairs gray; basal portion of third antennal segment variable, Sen Ci tO DE Oa Oks be a oo ae eae Wee init leet ie 2. Frons in 2 with one or two denuded calli; costal cell infuscated in MES ENES oe Wea ah eee 0 By ek ne incisuralis (W1k.) Frons completely pollinose; costal cell clear or lightly tinted ........ 3 38. Hair of abdomen whitish (some ¢¥ with median patches of black hair) ; if yellow hairs present laterally, over half of hind femora black; frons of 2 moderate in width; eye of both sexes in life usually with EMRE PCONTI =p acy ITO) aes ee tte ee ong Pt Go eee re a TTS tye Hair of abdomen yellow; femora variable, completely yellow to. half black; frons of 2 rather narrow; eye without band in life............... 5 4. Postocular fringe mostly black; second palpal segment stout basally but tapering to a point, with black and white hairs; mesonotum pre- Smaniaiitly black haired. «= -os56 ce ee duplex (Wlk). Postocular fringe mostly white; second palpal segment thick and short, predominantly white haired; mesonotum with few or no black RRO es a ei ee le oe ohioensis (Hine) 5. Abundant black hair on palpi and prescutal lobe; abdomen in 2 dark brown, narrowly yellowish on sides of first two tergites; hair of venter often white on first two segments; genae yellowish at least MPNPCE DOLLIONG. 56 6. eco Ss. ak pemeticus (Johns.) Only scattered black hairs on palpi and prescutal lobe; abdomen in 9 usually fuscous in centre, broadly yellowish on sides; hair of venter mostly yellow; genae gray with gray hairs .......... thoracicus (Hine) Atylotus bicolor (Wiedemann) Small to moderate in size (11 mm.); yellow or light orange; abdomen with a median indefinitely outlined dark area; wings hyaline, costal cell hyaline or pale yellow; eyes hairy. Male eye facets differentiated; eyes hairy. Ontario Records — Middlesex, June; Huron, July 10; Welland, July 24; Waterloo, Aug. 10; Wellington, Aug. 24; Hastings, July 6-26; Prince Edward; Leeds, July 9; Glengarry, June 27; Carleton, June 28-July 26; Nipissing, Aug. 11; Parry Sound, July 24; Sudbury. Atylotus duplex (Walker) Rather small (10 mm.) ; rusty black; abdomen often paler later- ally on first two tergites; costal cell tinged with yellow; second palpal segment tapered and acutely pointed; postocular fringe black; eyes hairy. Male eye facets differentiated; mesonotum and median portion of abdomen predominantly black haired; eyes hairy. Ontario Records — Muskoka, June 19-21; Parry Sound, June 18-July 20; Cotypes of Tabanus imitans Walker, a synonym of duplex in British Museum Natural History labelled St. Martins Falls, Albany River (Cochrane), (Philip, 1947). 99 Atylotus incisuralis (Macquart) Moderate in size (18 mm.) ; color and pattern variable, fuscous to grayish yellow; frons with two small calli neither of which touch eyes; costal cell infuscated ; bifurcation of third longitudinal vein angulate, rarely with a spur; eyes hairy. Male eye facets differentiated ; bifurcation of third longitudinal vein usually with a spur; eyes hairy. . Ontario Records — Cotypes of Tabanus intermedius Walker, a synonym of incisuralis, in British Museum Natural History labelled St. Martins Falls, Albany River (Cochrane), (Philip, 1947). *Atylotus pemeticus (Johnson) Small to moderate in size (11 mm.); dark yellowish brown; abdomen usually paler laterally; wings hyaline, costal cell pale yellow; eyes hairy. Male eye facets differentiated; abdomen laterally often more extensively pale than in female; eyes hairy. Ontario Records — Norfolk, June 19; Carleton, June 3-Aug. 6; Muskoka, June 19; Parry Sound, June 21-July 20; Cochrane, June 30-Aug. 17; Patricia, July 8. Atylotus thoracicus (Hine) Small in size (10 mm.) ; dull yellowish; abdomen with a median indefinitely outlined dark area which is broader posteriorly; wings hyaline, costal cell pale yellow; eyes hairy. Male eye facets differentiated; eyes hairy. Ontario Records — Middlesex, Aug. 15-26; Simcoe, July; Carlton, Aug. 9; Muskoka, June 26-July 28; Parry Sound, June 28-July 28; Timis- kaming, June 9. Genus HYBOMITRA Enderlein Key to the Species of Ontario Hybomitra — Females 1. Black species with first 3 abdominal segments mostly bright orange Ae a eh Sa ee ee ee eee pee ee = Abdomen otherwise marked cs. eS eee 3 2. Subcallus pollinose; palpi orange; usually some yellow hair on face and pleurae; wing lightly infuscated ier Ye iee ane Pa Ee, on criddlet (Brooks) Subcallus denuded; palpi black; hair of face and pleurae black; wings rather heavily infuscated <2 3 4 Oe eee cincta (F.) 3. Abdomen without median stripe of triangles and scarcely or not at at all paler laterally ; posterior margins of all segments with yellowish on whitish bands: seo 5 see eh eee ee xioiete® 4 4. Hind tibiae dark reddish brown to black, with black hair ...................... ear ed ears See eanc SOM Eh PRS SREY eg Ne eds eT sexfasciata (Hine) Hind tibiae yellow or orange with yellowish hair .......................... 5. Prescutal lobe reddish; abdominal bands broad; subcallus pollinose We ema eer cee yma er hy em Sei in eo zonalis (Kirby) Prescutal lobe black; abdominal bands a narrow fringe of pale hair; subeallus largely denuded ..................... Peteeeae ce: aequetincta (Becker) 6. Subcallus: denuded*..) ise ee ee 7 Subcallus pollinese:.25 5 oe Ses Ee 14 z0: ie 12. 13. 14. 15. 16. ve 18. Subcallus swollen; whole face below eyes denuded and shining; small Species with dark, wing markings 98 ela. hinei (John.) Subealis normals trace pelow not. Shining)... [65a Oo ia, 8 Abdomen broadly orange brown laterally, the median black area con- BeICRCCUPOME CITC FSCOTMEND 8 joe! sy. 21 Ranta a PE Wa 9 Abdomen not broadly orange brown laterally; if paler laterally, the median dark area on the third segment is broad and not constricted ee rE et eT tN fg! ue A PAT iy Sy ae AUR ee ares | . Basal callus shiny and protuberant; all cross veins strongly spotted RTM LOW. oth ery et A 09., a cleats lastophthalma (Macq.) Basal callus flat and wrinkled; spots on cross veins if present not Bernt anG CISULNGE AN ee gk eT Re ee nuda (McD.) Eyes apparently bare; basal portion of third antennal segment nar- row; abdomen brownish, faintly reddish brown laterally and with a median row of indistinct whitish triangles ................ difficilis (Wied.) Eyes hairy and not with above combinations of characters ........ 1 Palpi extremely slender; proboscis elongate; thorax subshining ........ i Rae ee a he ee Longiglosse (Philip) Palpi not slender; proboscis normal; thorax not subshining ........ 12 Abdomen usually with considerable orange brown laterally; bifurca- tion of third longitudinal vein with a dark spot; costal cell infuscated ; palpi very stout; third antennal segment stout; no stump vein at ‘Diturcation of third longitudinal vein... metabola (McD.) Not with this combination of characters; a stump vein often present at bituecation of third longitudinal vein 9°....../.... SL ee See rs BRN 1433 Femora black; first antennal segment about as long as greatest width co an GRRE IA: UNC Se Si GA as AOL a 2 eR OR cE tetrica (Marten) Femora brownish; first antennal segment longer than wide .................. ee rte eee Be ty liorhina (Philip) Abdoman black with a median row of distinct white triangles and no SuletaberaleSpOtS: ay tees ok aie hk ek trispila sodalis ( Will.) Paog omen OUNneTWISe Marked se ew ae, 15 Abdomen broadly orange-brown laterally, the median black area con- pebieceCH OhLhe bind SseOment: rea a ks a ie 16 Abdomen not as above, if paler laterally median dark area of third Seoment is broat and. not-constricted . 2. 20 Second palpal segment rather stout especially at base; antennae mostly Greene i ea ee Mea Wed el epistates (O.S.) Second palpal segment slender; at least annuli dark ............0....... 1eF/ Second palpal segment unusually slender, at least five times as long as greatest width; basal portion of third antennal segment about four fifths as wide as long and annulate portion rather short; almost no MOMS OMCISIOM ee hee ee Coke ie koe trepida (McD.) Second palpal segment moderately slender, not more than 414 times at long as greatest width; basal portion of third antennal segment not more than three fifths as wide as long and annulate portion eelanively: long: dorsal: EXciSiom- distinct «io ore ee 18 Second palpal segment about 414 times as long as greatest width, rather sharply pointed; third antennal segment with a deep dorsal excision so that dorsal angle has tendency to project forward; basal eallus usually finely wrinkled or striate ...............0...000..... arpadt (Szil.) Second palpal segment rarely more than 4 times as long as greatest width, usually less, usually blunt at tip; dorsal excision more shallow 101 tO: 20. 21. 22. 23. 24. 25. 26. 21. 28. Zoe with dorsal angle not projecting forward; basal callus rarely striate ~ Basal callus quadrangular, rarely aeincd to median callus; palpi yel- lowish white about 3 times as long as greatest width .. affinis (Kirby) Basal callus rounded above and often joined to median callus; basal portion of third antennal segment rather slender and not deeply excised ; palpi yellow, 31% to 4 times as long as greatest width; median black area of abdomen often greatly reduced .......0..000.000..00cocceeecceeeeeeeeee RRs Ceti erties rane gia me Witney eh Ry et mary Gc affinis aurilimba (Stone) Second palpal segment slender, scarcely thickened at base .. ........ 21 Second palpal segment stout, especially so at base ............ 28 Femora, except base of hind femora, brown; sides of abdomen reddish brown; second palpal segment extremely slender; third antennal seg- ment practically without dorsal excision ................. minuscula (Hine) Femora usually black, if brown, sides of abdomen not with consider- able ‘oran@e-brown 5320 ee a Ze, Frons 3 to 314 times as high as wide, somewhat widened above; third antennal segment with acute dorsal angle and deep excision ............... Cee UT CE aa anh Shey aerial beeaae Mie ee Diese t gees dark form of arpadi (Szil.) Frons usually less than 3 times as high as wide; third antennal seg- ment with obtuse dorsal angle and very shallow excision ................ Prescutal lobe black; hair of palpi long, uneven and semi-erect ... 24 Prescutal lobe pale; hair of palpi as above or short and lying smoothly against) seoment ee eR eC 25 Proboscis long, palpus not reaching base of labellae .... hearlez (Philip) Proboscis short, subequal in length of palpi or slightly longer .............. Rl nA a a aie a ae ee Ce recat RN at RU ye tien FP astuta (O.S.) Frons about twice as high as wide; frontal callus pale brown; femora brown ;costal-cell clear-35 207-2 0 ee ee itasca (Philip) Frons more than twice as high as wide; callus brown to black; femora rarely dark brown, usually at least partly black; costal cell infuscated PR fa MAN oe NN EU EE ERLE (ea Mai A Gt 26 Hair of palpi long and uneven, semi-erect; base of third antennal segment narrow; hind femora black on basal half, balance brown ee Reins Win tn tea Crore elm n rete sy Sn ie frosts Pech. Hair of palpi short and lying smoothly against segment; base of third antennal segment not very narrow; hind femora brownish to com- pletely blacks 2.20.08 Se ee Ee 2 Femora brown or partly black; frontal callus brown; palpi slightly swollen at “knee” and tapering acutely to-a pont. ae (Form A) bE ON ayy Ao 2 Scat SM Mey Mel Ute a ite a 1h een Ae get ee eee ree typhus (Whitney) Femora black; frontal callus black or dark brown; palpi slender but not acutely tapered fromknee x ye a ee ee (Form B) RSE WM AICP ney, en A Ger eee er eae oe typhus (Whitney) Bifurcation of third longitudinal vein with a distinct spot; third antennal segment stout and with a rather distinct dorsal excision... Pe an Re Pe ne war res Nar STAY Se eho illota (O.S. ) Bifurcation without a distinct spot; third antennal segment more slender: 00-2228 5 ee ee 20 Legs nearly uniformly brownish, rarely femora somewhat darker; third antennal segment very slender ; prescutal lobe black ...................... we ee INA 8 tes oll a eS ot, Sa era an eats aie microcephala (O. = , Femora black or grayish; prescutal lobe rarely black ...................... 102 30. dl. 10. Stump vein usually present at bifurcation of third longitudinal vein; pollen of head gray; blackish gray species usually over 15 mm. ............ DE Nre er e ae Se IC cee Oy ae! oR She tetrica hirtula (Bigot) Stump vein rarely present; pollen of head yellow or with a yellowish tinge; yellow-brown to brownish black species usually under 15 mm. Fg Ey TI eo Ee ee MNES aT A, toe etc te re nee ee ol Basal callus strongly convex, projecting on subcallus as a small bare triangular area; frons broad and distinctly widened above; stump TOTTI PEL ST ae peeve ie ee" UY Ged opaca (Coquillett) Basal callus not strongly convex; subcallus without triangular bare area; frons narrower, parallel-sided or slightly widened above; stump Meh present Orvabseng i. Se frontalis Walker Key to the Species of Ontario Hybomitra — Males Stiff hairs along mid line between eyes .................... difficilis (Wied. ) No stiff hairs along mid line between eyes .........0000..000. eee. Black species with first 3 abdominal segments mostly bright eee 3 Genae dark gray pollinose; palpi orange brown: wings lightly infus- cated; third abdominal segment normally with a dark median spot WE ee ee ae ee See criddlet (Brooks) Genae dark brown pollinose; palpi dark brown to black; wings rather heavily infuscated; third abdominal segment normally without a dark MACWIRDMES DOL Nee ate ee AP ee cincta (F.) Abdomen without median stripes or triangles and not paler laterally; pale markings in form of bands on posterior margins of segments 5 Abdomen with median stripes or triangles or paler laterally or both 0 Hind tibiae dark reddish brown to black, with black hair ....................... ee ere et tae op ee eA sexfasciata (Hine) Hind tibiae yellow or orange with yellowish hair ..........0................. Prescutal lobe reddish; abdominal bands broad ........ zonalis (Kirby) Prescutal lobe black; abdominal bands a narrow fringe of pale hair eee ee a eh ke aequetincta (Becker) Small dark species with gray, protuberant frontal triangle; genae black, somewhat shining; a dark cloud on wing near stigma ................ «oo SE gf cea vhaad: se ON SA SRR SA sce Ue ONO Es Pa aC eg ae Se hiner Co Differing in one or more characters from the above ...................... Proboscis 4 times as long as very small slender palpi; first he abdominal segments reddish brown laterally and first 5 segments with a pale narrow posterior band; thorax and abdomen subshining re re ea ke ie ele longiglossa (Philip) Nor with this combination of characters |.) <2 GA. 4 Cross veins and bifurcation of third longitudinal vein with distinct dark spots; abdomen laterally, broadly orange ...............00..000fcccecceeeeees be SAG sais PO glee CL SOR Rah et ne a Sat eRe lasiophthalma (Macq.) Wings hyaline, tinted or with bifurcation only having a dark spot 10 Abdomen black, obscurely reddish laterally but no distinct sublateral spots; a conspicuous row of white median triangles sis. A Me Ae ete ahead te rane ee he ee ee CSI sodalis (Will) Et, 12. 13. 14. 15. 16. 17. 18. iL): 20. 21. 22. 25. Small species not over 12 mm. with very small slender second palpal segment; sides of abdomen broadly dark orange but first segment usually completely black; third antennal segment with a very shallow dorsal excisions 2 a ae ol minuscula (Hine) Species usually over 12 mm. or if smaller, second palpal segment stout and dorsal-excision distinct)! =e bi Abdomen broadly orange-brown laterally, median black area con- stricted: on third :serement. .... 62-43 Ann eee, a eee iy Abdomen not broadly orange laterally; orange sublateral spots may be present but black area on third segment is not constricted ........ 20 Second, third and fourth abdominal segments with median tufts of erect black: hair ss 953/05. ah cata Ae age oe eae ew een arpadi (Szil.) Median black hair not in form of tufts execpt rarely on second Sepment 00 2 Ee ee AS ae 14 First abdominal sternite almost entirely black or with a small orange area’ sublaterally =.) bs 0 hci Go a 15 First sternite orange, occasionally with a small dark area in centre 17 Frontal triangle rather flat; base of third antennal segment rather slender; palpi moderately stout, yellowish-brown; wing often dilutely infuscated without intensification in anterior portion; costal cell dilutely tinted or clearis 27. os a ee frontalis (Walker) Frontal triangle protuberant; base of third antennal segment rather stout; palpi very stout, grayish brown; anterior portion of wing often infuscated along veins, in basal cells and at bifurcation of third longitudinal vein; costal cell tinted... 2 SS a ee 16 Claws of fore tarsi subequal; median black area of abdomen rather FOO: eso eee Ne Mts rae ae 0 yn eet kee en elie eae metabola (McD.) Outer claw of fore tarsi longer than inner claw; median black area of abdonien narrow: 3. S at ei ee ee eee ee nuda (McD.) Third antennal segment including annuli reddish; second palpal seg- ment very stout, only slightly longer than thick ........ epistates (O.S.) Third antennal segment with at least annuli black; second palpal seg- ment moderately stout to:slender <0 6. oe ee ee Large and small eye facets differentiated; second palpal segment at least twice as long as thick; usually under 15 mm. .... trepida (McD.) Almost no differentiation in size of eye facets; usually 16 mm. or more; second palpal seement.variable ....2.......2.. 0) 2S ee ee 19 Second palpal segment yellowish white, about 114 times as long as thick; base of third antennal segment distinctly excised ..................... SRE r CNR ae te Dg TE SUE A EEE Go Aig ert ex cy ches ae cena affinis (Kirby) Second palpal segment yellow, about twice as long as thick; base of third antennal segment slender and shallowly incised; median black area of abdomen usually much reduced ........ affinis aurilimba (Stone) Prescutal lobe: black: 3 ih aa 2 ee ee DAL Prescutal-lobe pale, at least on dis¢(:) vs 6 ee Ze Femora brown; palpi swollen at base and tapering to an acute tip ... A EP DRE SA RAD Sate GaP ONE yt SAE aE ets meri Ae ane ELL microcephala (O.S.) Femora black; palpi small, not swollen at base, not with an acute tip eid thle BE i uae by Bao BOAO: 5 ape ties ais eee ee nr SET astuta (O.S.) Bifurcation of third longitudinal vein with a distinct spot. ............. 23 Bifurcation of third longitudinal vein without a distinct spot 24 Hind tibiae crange-brown; abdomen rather broadly orange - brown laterally ; costal cell and basal portion of wing with considerable in- fuscation; claws of fore tarsi subequal.2. 27. metabola (McD.) 104 24. 25. 26. 27. 28. 29, Hind tibiae dark reddish brown to black; abdomen narrowly yellowish laterally ; costal cell and basal portion of wing lightly infuscated; outer claw of fore tarsi about ¥3 longer than inner claw ........... illota (O.S.) A stump vein at bifurcation of third longitudinal vein .................... 25 No stump vein at bifurcation of third longitudinal vein ................ 26 Femora yellow-brown to dark brown ........................ liorhina (Philip) iemore blacks ie ej VED ARCOM eta ner fis chet Ayton NS tetrica (Marten) (To date no characters have been found to separate the male of tetrica tetrica and tetrica hirtula). ali yvellowish to white, rather stout... 0 eee ee, 27 Palpi orange brown to dark brown, slender; if yellowish, very slender cocoa sadeg leech Me LEM ATT CCUM SRS Sil ee pee hA antec Maat oC) Weal id ae a ee rae 28 Sides of black mid-dorsal abdominal spots concave giving mid-dorsal Siripe’ a serrated appearance 0 opaca (Coquillett) Sides of black abdominal spots relatively straight .. frontalis (Walker) Head relatively small; eye facets scarcely differentiated ; second palpal segment brown, paler at apex, somewhat clavate; hind femora brown, intecibslent Ceawmkemedi: aes Foes Nt es ye frostt Pech. Head relatively large; eye facets rather distinctly differentiated; second palpal segment yellow to brown, rather cylindrical; hind hemokavvyariableorten completely. black. ..c eee. 7s) Legs mostly brown; hind femora darker at base; palpi yellowish ..... MPEDONSIDAS ee nie es chats ci Es ies typhus (Whitney) ersamostiy, black: palpi brownish 0.00.0 see ea (Form B) Re ee enn pl ato ok ete Oe MEET The typhus (Whitney) Hybomitra affinis (Kirby) Moderate in size (18 mm.) ; brownish; abdomen broadly orange brown laterally; wings usually with a faint tint which becomes heavier along longitudinal veins; second palpal segment moder- ately slender; third antennal segment moderately excised; costal cell yellow;eyes hairy. Male eye facets scarcely differentiated ; median areas of black hairs on abdomen occasionally forming a tuft on the second segment; eyes hairy. Ontario Records — Norfolk, June 27; Haldimand, Aug; Wentworth, June 26-July 7; Waterloo, June 3-July 9; Wellington, June 7-July 11; Bruce, June 18; York; Victoria, June 21-27; Peterborough, July 3; Hastings, June 7-July 27; Lennox and Addington, June 30; Grenville, May 29-June 23; Glengarry, June 7; Carleton, May 29-July 11; Renfrew, June 22; Nipissing, June 11-July 14; Parry Sound, July 20-25; Sud- bury, July 11; Manitoulin, June 14; Algoma, June 4-Aug. 16; Timis- kaming, June 26; Cochrane, June 23-Aug.; Thunder Bay, June 9-July 20; Kenora, June 24-July 10; Patricia, June 15-July 30. Hybomitra affinis aurilimba (Stone) Moderate in size (17 mm.); orange brown; abdomen broadly orange brown laterally, sometimes dark median area on second and third tergites to a shadow; wing with a yellowish tint; costal cell dark yellow; eyes hairy. Male eye facets scarcely differenti- ated; black median area of abdomen more extensive than in most females; eyes hairy. . Ontario Records — Norfolk, June 15-Aug. 23; Waterloo, July 16; Welling- ton, Aug. 1; Victoria, June 27; Muskoka, June 26; Parry Sound, June 23-July 27; Nipissing, June-July; Sudbury, July 20. 105 Hybomitra arpadi (Szilady) (= gracilipalpis [Hine}) Moderate in size (16 mm.) ; brownish; abdomen broadly orange brown laterally but this greatly reduced in some specimens; second palpal segment ‘slender; third antennal segment deeply excised; costal cell yellow; eyes hairy. Male eye facets scarcely differentiated ; median tufts of erect black hair present on second, third and fourth abdominal segments; eyes hairy. Ontario Records — Bruce, June 18; Nipissing, June 10-29; Parry Sound, June 18-July 22; Cochrane, June 27-July 27; Patricia, June, Hybomitra astuta (Osten Sacken) | Moderate in size (14 mm.); brownish black; abdomen with 3 rows of grayish triangles, prescutal lobe dark; wings hyaline, costal cell pale yellow; eyes hairy. Male eye facets scarcely differ- Sane pale abdominal markings with an orange cast; eyes airy. Ontario Records — Carleton, June 5; Simcoe; Parry Sound, July 29-Aug. 27; Nipissing, Aug. 2-10; Algoma, July 3; Cochrane, Aug.; Thunder Bay, July 17; Patricia, Aug. 9-13. Hybomitra cincta (Fabricius) Moderate to large in size (20 mm.) ; black with an orange band covering most of first three tergites; third tergite completely yellow; subcallus partly denuded; wing with dark yellow tint; eyes practically bare. Male eye facets little differentiated; ab- dominal pattern as in female; eyes hairy. Ontario Records — Simcoe, July 25; Hastings, July 14-22. Hybomitra criddlet (Brooks) Moderate in size (18 mm.) ; black with an orange band covering most of first three tergites but no tergite completely yellow; subcallus pollinose; wing with pale yellow tint; eyes practically bare. Male eye facets little differentiated; abdominal pattern as in female; eyes hairy. Ontario Records — Hastings, June 26-July 7; Renfrew, June 24; Nipis- sing, June 19-July 7; Timiskaming, June 26; Sudbury; Algoma, July 8-Aug. 21. Hybomitra epistates (Osten Sacken) Moderate in size (14 mm.); brownish; abdomen broadly orange brown laterally; second palpal segment rather swollen; wings with a faint yellow tinge which deepens anteriorly to include costal cell; eyes hairy. Male eye facets scarcely differentiated ; eyes hairy. Ontario Records—Essex, June 16-Aug. 1; Kent, June 21-July 7; Lambton, June 24-July 17; Norfolk, June 15- Aug. 23; Wentworth, June 27-Aug. 15; Waterloo, June 19-July 24; Wellington, June 12-Aug. 15; Huron, June 28; Bruce, June 18-July 10; Dufferin, July 15; Peel, June 4-6; York; Simcoe, July 8-28; Victoria, June 1-27; Northumberland, July 17; Hastings, July 10-27; Lennox and Addington, June 30-Aug. 17; Leeds, July 8-10; Grenville, June 5-July 3; Carleton, July 3; Renfrew, June 24; Muskoka, June 22-July 27; Parry Sound, July 1-29; Nipis- sing, June 2-July 14; Sudbury, July 4-20; Algoma, June 4-July 3; Cochrane, June 27-Aug.; Thunder Bay, June 22-July 20; Kenora, June 24; Patricia, June 30-July 30. 106 Hybomitra frontalis (Walker) (includes subsp. septentrionalis Loew) * Moderate in size (14 mm.); dark brown to blackish; abdomen usually with faint grayish or yellow median triangles and rather round, yellowish, reddish or grayish sublateral spots which may or may not reach the hind margins of any of the tergites; wing hyaline, costal cell tinged with yellow; eyes hairy. Male eye facets slightly differentiated but line of demarcation indistinct; sublateral spots reddish, occasionally confluent to the point of forming a sublateral band; eyes hairy. Ontario Records—Wentworth, Aug. 13-20; Waterloo, July 21; Wellington, July 16-Aug. 11; Bruce, July 10; Dufferin, July 15; Peel, July 1; Simcoe, July 25; Victoria, June 27; Peterborough, July; Hastings, June 25; Frontenac, Aug. 8; Nipissing, June 22; Sudbury, July 4; Cochrane, July 9-Aug. 12; Thunder Bay, July 5-24; Patricia, July 8-Aug. 10. Hybomitra frosti Pechuman Moderate in size (13 mm.); blackish brown; abdomen with 3 rows of grayish spots, the outer ones sometimes pinkish; prescutal lobe pale; costal cell yellow; eyes hairy, Male eye facets scarcely differentiated; eyes hairy. Ontario Records—Parry Sound, July 19-Aug. 27. Hybomitra hearlet (Philip) Rather small (11 mm.); blackish; abdomen with 3 rows of grayish spots; prescutal lobe normally dark; costal cell yellowish ; proboscis much longer than in any related forms; eyes hairy. Male unknown. Ontario Records—Cochrane, June 16-July 29; Thunder Bay, June 23; | Patricia, July 20. Hybomitra hinei (Johnson) Small to moderate in size (11 mm.) ; abdomen shining black with orange laterally; subcallus denuded; wing tinged with yellow, a dark poorly defined band in vicinity of discal cell, costal cell dark yellow; eyes with short hair. Male eye facets little differentiated ; frontal triangle prominent, grayish; eyes hairy. Ontario distribution unknown. Reported from the province by Philip (1947). Hybomitra illota (Osten Sacken) Moderate in size (13 mm.); brownish black; abdomen with faint median triangles and grey or yellowish gray sublateral spots; wings hyaline with pale yellow costal cell and faint brown- ish spots; eyes hairy. Male eye facets scarcely differentiated ; sublateral abdominal spots larger than in female and usually more yellowish; eyes hairy. Ontario Records—Essex, May 28-June 29; Kent, June 25; Lambton, June 24; Norfolk, June 18; Lincoln, June 18; Wentworth, June 4-July 23; Waterloo, June 19-July 23; Wellington, May 30-July 29; Dufferin, July 15; Bruce, June 18-28; York, June; Victoria, June 9-27; Hast- ings, May 21-June 26; Carleton, May 29-June 24; Muskoka, June 19- *Agrees with the work of McAlpine, J. F. Variation, distribution and evolution of the Tabanus _ (Hybomitra) frontalis complex of horse flies (Diptera: Tabanidae). Canadian Ent. (in press) 107 July 28; Parry Sound, June 21-July 28; Nipissing, June 3, Aug. 11; Sudbury, July 1-11; Algoma, July 13-Aug. 11; Timiskaming, June 26-July 10; Cochrane, June 27-July; Thunder Bay, June 18-July 11; Kenora, June 25-July 6; Patricia, June 15. Hybomitra lasiophthalma (Macquart) Moderate in size (14 mm.) ; brownish; abdomen broadly orange brown laterally; subcallus denuded; wings hyaline or faintly tinted, with conspicuous dark spots and yellow costal cell; eyes hairy. Male eye facets little differentiated; frontal triangle gray- ish; eyes hairy. Ontario Records—Essex, June 2-17; Kent, June 14-25; Lambton, June 12; Middlesex, June 10-July 3; Norfolk, June 15-Aug. 23; Lincoln, June 14-25; Wentworth, May 23-June 29; Halton, June 21; Waterloo, June 24; Wellington, May 25-July 9; Peel, June 9-12; Bruce, June 18-28; Grey, June 18; Simcoe, May 28-June 19; York, June 7-July 6; Victoria, June 1-27; Peterborough, July 3; Hastings, June 7-July 10; Lennox and Addington, June 29; Frontenac, June 22; Grenville, June 16-July 28; Leeds, June 13; Glengarry; Carleton, June 2-July 17; Renfrew, June 7-24; Nipissing, May 28-Aug. 15; Parry Sound, July 2-22; Sudbury, July 4-11; Manitoulin, June 14; Algoma, June 2-July 12; Timiskaming, June 26; Cochrane, July 9; Thunder Bay, June 21-July 10; Kenora, June 24-July 2. Hybomitra lhorhina (Philip) Moderate in size (14 mm.) ; grayish brown; 3 rows of pale ab- dominal spots; legs brownish; bifurcation of third longitudinal vein with a stump vein; subcallus denuded; eyes hairy. Male eye facets differentiated; frontal triangle pollinose; eyes hairy. Ontario Records—York, June 20; Parry Sound, July 20; Sut oaL July 20; Manitoulin, Aug. 5 Cochrane, Aug. 12. Hybomitra longiglossa (Philip) Small to moderate in size (12 mm.) ; blackish, abdomen with some reddish brown laterally; subcallus and centre of frontoclypeus denuded; palpi extremely slender; proboscis very elongate; eyes hairy. Male eye facets scarcely differentiated; frontal triangle somewhat protuberant, pollinose; palpi very small; proboscis very elongate; eyes hairy. Ontario Records—Carleton, June 3-18; Cochrane, June 6-29; Patricia, June 21. Hybomitra metabola (McDunnough) Moderate in size (13 mm.) ; brownish black; abdomen with faint median triangles and yellowish sublateral spots on the second, third and fourth tergites; wings hyaline with a dark yellow costal cell; faint brownish spots and a tendency for the veins toward the base of the wings to be outlined in yellowish brown; subcallus denuded; eyes hairy. Male eye facets scarcely differenti- ated; thorax and abdomen rather shiny; eyes hairy. Ontario Records — Wentworth, June 7-July 3; Waterloo, May-June; Hastings; June 11; Grenville, May 29; Carleton, June 3; Sudbury, July 1; Cochrane, June 6-July 12; Thunder Bay, June 24; Kenora, June 20; Patricia, June 15-July 21. 108 Hybomitra microcephala (Osten Sacken) Moderate in size (14 mm.) ; grayish black; abdomen with 3 rows of grayish or pinkish gray spots which are largest on the second tergite; legs uniformly brown to reddish; wings hyaline with yellowish costal cell and tendency for veins to be outlined in pale yellow; eyes hairy. Male eye facets scarcely differentiated ; sublateral abdominal spots often reddish; eyes hairy. Ontario Records—Bruce, Aug. 19; York, Sept. 10; Hastings, Sept. 2; Haliburton, Aug. 20; Nipissing, July 13-30; Muskoka, July 25-Aug. 24; Parry Sound, July 18-Aug. 27; Algoma, July; Kenora, July 26. Hybomitra minuscula (Hine) Small to moderate in size (11 mm.); rather shining blackish brown; abdomen with considerable orange brown laterally; wings tinted with tendency for veins to be outlined in a deeper tint, costal cell yellow; second palpal segment very slender; eyes hairy. Male eye facets scarcely differentiated; eyes hairy. Ontario Records—Middlesex, July 1-Aug. 25; Wentworth, June 29-July 20; Waterloo, July 21; Dufferin, July 15; Carleton, June 26-Aug. 9; Muskoka, June 26-Aug. 6; Parry Sound, June 28-Aug. 22; Nipissing, Aug. 2; Cochrane, July. Hybomitra nuda (McDunnough) Moderate in size (15 mm.) ; brownish; abdomen broadly orange brown laterally; subcallus denuded; basal callus rather dull and wrinkled; wings hyaline with veins near base and anteriorly out- lined in dark yellow; costal cell yellow; second palpal segment greatly swollen and pale in color; eyes hairy. Male eye facets scarcely differentiated; eyes hairy. Ontario Records—Wellington, June 3; Bruce, June 4-18; Simcoe, June 19; Victoria, May 27; Peterborough, June; Hastings, June 7-25; Grenville, May 29-June 23; Carleton, June 7-9; Renfrew, June 22-July 4; Nipissing, May 25-July 4; Haliburton, May 25; Muskoka, June 4-July 12; Parry Sound, June 20; Sudbury, June 5-July 11; Algoma, June 6-Aug. 5; Cochrane, June 27; Thunder Bay, June 13-July 24; Kenora, June 30-July 2; Patricia. Hybomitra tetrica (Marten) Moderate in size (16 mm.) ; grayish black; 3 rows of gray spots on abdomen; femora blackish; bifurcation of third longitudinal vein with a stump vein; subcallus all or partly denuded; pollen of head gray or white; eyes hairy. Male eye facets slightly differ- entiated ; eyes hairy. Since all males of tetrica studied to date have the frontal triangle pollinose, no characters seem to be available to separate the typical form of this sex from hirtula. Ontario Records—Cochrane, June 14. Hybomitra tetrica hirtula (Bigot) Similar to typical form but subcallus pollinose. Ontario distribution unknown. Reported from the province by Philip (1947). j Hybomitra trepida (McDunnough) Moderate in size (14 mm.) ; brownish; abdomen broadly orange brown laterally; basal portion of third antennal segment rather 109 broad, annulate portion relatively short; palpi very slender; wing faintly tinted, costal cell yellow; eyes hairy. Male eye facets rather distinctly differentiated; second palpal segment very small; eyes hairy. Ontario Records—Essex, June 28-30; Norfolk, June 15-Aug. 23; Went- worth, July 17; Waterloo, June-July; Wellington, July 15; Huron, June 23; Bruce, June 18-July; York, July 9; Peterborough, July 4; Hastings, July 7; Leeds, June 25; Carleton, June 5-July 11; Renfrew, June 22-July 4; Haliburton, July 31; Muskoka, June 18-July 25; Parry Sound, June 28-July 29; Nipissing, June 3-Aug. 4; Manitoulin, June 30-July 2; Sudbury, June 19-July 11; Algoma, June 4-July 26; Cochrane, Aug.; Thunder Bay, June 14-July 20; Kenora, June 22-July 26; Patricia, June 30-July 30. Hybomitra trispila sodalis (Wiedemann) Moderate in size (15 mm.); blackish; abdomen black with a median row of grayish white triangles; wings tinted, costal cell dark yellow; eyes with fine inconspicuous hairs. Male eye facets scarcely differentiated; sides of abdomen often tinted with orange-brown; eyes hairy. Ontario Records—Middlesex, July 17-18; Huron, July; Waterloo, July 16-24; Wellington, July 7-Aug. 8; Wentworth; Welland; Dufferin, July 15-17; Peel, Aug. 11; Simcoe, July 21-25; Northumberland, July 24; Hastings, June 14-July 26; Frontenac, Aug. 5; Leeds, Aug. 12; Carleton, July 19-25; Muskoka, July 13-25; Parry Sound, July 21-27; Nipissing, June 29-Sept. 4; Sudbury, July 20. Hybomira typhus (Whitney) Small to moderate in size (11 mm.) ; blackish; abdomen with a median row of grayish triangles and larger sublateral pale spots which are sometimes pinkish in ground color; prescutal lobe red- dish; wings hyaline with a dark yellow costal cell and occasionally faint spots; eyes hairy. Male eye facets differentiated ; eyes hairy. The above description will apply to both forms of this species. Form A at its extreme is paler and larger than Form B with brown frontal callus and legs and a pale second palpal segment which is acutely tapered and pointed. Males are readily associated with each form. The shape of the second palpal segment seems to be a constant difference between the two forms but the other characters show apparent intergradation. It is possible typhus is a composite species. Ontario Records—Wentworth, June 19; Waterloo, July 6; Wellington, July 14-28; Dufferin, July 15; Peterborough, July 4; Hastings, June 26-July 24; Carleton, June 5-July 11; Muskoka, July 16-Aug. 4; Parry Sound, July 8-29; Nipissing, June 27-July 22; Algoma, July 25-Aug. 17; Sudbury, July 20; Cochrane, June 27-Aug. 12; Thunder Bay, June 22-July 24; Patricia, July 10-27. ‘Hybomitra zonalis (Kirby) Moderate in size (18 mm.) ; black; abdominal tergites with yellow bands along hind margins; eyes hairy. Male eye facets barely differentiated with no definite line of demarcation; eyes hairy. Ontario Records — Middlesex, June 17; Carleton, June 5-24; Renfrew; Nipissing, June 19-July 15; Muskoka, June 22; Cochrane, June 14- July 17; Algoma, June 9-July 24; Thunder Bay, June 14-July 4; Kenora, July 24; Patricia, June 20-July 15. 110 10. 13. 14. Genus TABANUS Linnaeus Key to the Species of Ontario Tabanus—Females . Abdomen unicolorous or with narrow indistinct posterior bands... 2 Abdomen with one or more median triangles or a median stripe... 6 Subcallus denuded; abdomen and wings entirely or almost entirely black ; abdomen often with a whitish bloom ........................ atratus Fab. Subcallus not denuded; wings at least partly hyaline ................... 3 Palpi dark brown to black; white pollinose mesonotum contrasting WRUNG, GBT EC BilayewG real enn Eicoee «aueee ema sO Daren tile aii Shr ena: Dae mania ae Ie ote Palpi pale to reddish brown; mesonotum not greatly contrasting with AOTC Meer Sey ee nk fp Sar, Dyk me Te Cd oe eh oe eet oe em 5 Frons orange brown, moderate in width; wing veins not margined with brown although darker clouds may be present .......... stygius Say Frons gray, broad; wing veins margined with brown .. subniger Coqu. Wing hyaline with dark brown costal cell; abdomen usually with hattow eray posterior bands:.2..2 00.2.8... ee. americanus Forster Wing uniformly dilutely infuscated; costal cell yellow; abdomen sometimes with traces of small median triangles .................... calens L. Abdomen with a longitudinal median stripe which may or may not be somewhat widened at posterior margins of segments ................ Abdomen with median markings not forming an uninterrupted stripe sensuaces tesa tautsls lee (Ais 1a ik AAS UES a coins ale ete ent ni ORE cet mio 1 Lateral markings forming a stripe on each side of median stripe and parallel to it but often shorter than median stripe; spots forming mice stripe nearly parallel-sided «oc... 00....00 Lateral markings broken into separate, often roundish spots; spots forming median stripe usually widened at posterior margins of ab- WOnMmer SCOMONESY hel ey ee ee ca ete i Prescutal lobe camel ane with rest of mesonotum; frons nearly parallel-sided; annulate portion of third antennal segment usually longer than basal portion costal cell infuscated; eye in life with a Sime len punple: band) 6. a quinquevittatus Wied. Prescutal lobe paler than mesonotum; frons widened above; annulate portion of third antennal segment usually shorter than basal portion; costal cell hyaline; eye in life with two purple bands ........................ Sevtcium and thorax concolorous (4.0.0 ioe a lineola Fab. Scutellum reddish, sometimes faintly, on posterior margin ees predominantly reddish =). similis Macq. -Femora of at least fore and hind leosudarkenede 2g) rs athe ale vittiger schwardti Philip . Frons narrow, widened above: eestal cell hyaline; palpi white cocesuguihe sdecwede aad Ric (Ub Ue ios er ARIA dnp 2 ed oi ia aN pasate ee ne eras Weel sackeni Fairch. Frons broader, parallel-sided; costal cell colored; palpi yellow, much swollen at base Pe he rie Ne aie iP el rr eee eee ae sagax O.S. . Thorax white pollinose; abdomen dark with white triangles ......... 13 Thorax not white or contrasting strongly with the abdomen ........ 14 Large white triangles on third, fourth and fifth abdominal segments; KORE CMOIAe WICOOKEO 225) 6.8 ee trimaculatus Palisot Small white triangles on the second to sixth abdominal segments; fore tibiae essentially unicolorous................. superjumentarius Whitn. Abdomen with both median and sublateral spots ........................... 15 Abdomen without sublateral spots although abdomen may be paler piaely Vance UE GUO NOS aac remy Giguere A resto JU attr te Gin tO gene ea 22, 15. SPeGleS cea a et eee reinwardtu Wied. Bifurcation without a dark spot; color variable) as 16 16. Small species, usually 12 mm. or less; frons widened above; costal eell -nyahme: (2008 Oe aN ae Ltn Larger species, usually 13 mm. or more and differing in at least one other character from the above’) 2 ee a 17. Median callus large; palpi not swollen basally or sharply pointed; eye in life with 2 purple bands =, 3'. 2 ee pumilus Macq. Median callus slender; palpi swollen basally but with apex acute; eye in life unicolorous or with a single purple band ; |... 2 18 LS. Hive. vnicolorous =.) ee sparus Whitn. Eye with asingle purple band”... sparus milleri Whitn. 19. First antennal segment swollen above; sides of subcallus with a few hairs laterally. cca ee eee eee fairchildi Stone First antennal segment not swollen above; side of subcallus without Wa@IPS oe So a ee 20 20. The sublateral white abdominal spots considerably larger than the small median triangles and usually reaching anterior border of second and third seoments.7. (2 oe a ee marginalis Fab. The median triangles are relatively larger and sublateral spots smaller rarely extending to anterior border of segments .....................02:..00. 7 21. Vertex depressed with a swollen adjacent area; frons about 4 times as high as wide; last antennal annulus yellow; median triangle of third abdominal segment narrowly reaching anterior margin ............ OR ae mine tare AVE Bet aL Es. Cem men iG fulvicallus Philip Vertex slightly depressed or flat; frons about three and one half times as high as wide; last antennal annulus black; median triangle of third abdominal segment not reaching anterior margin .............. vivax O.S. 22. Bifurcation of third longitudinal vein with a brown spot ...................... eit i, Me a ees Oe ins SPM uber a Moran | ALTE Sr ge sh sulcifrons Macq. Bifurcation without a brown spot although veins may have indistinct brown Mareins 0 ee ae ee ee 23 23. Wings hyaline; costal cell hyaline or slightly tinted; small species with conspicuous median triangles and with subcallus often partly — GENCE ee eet ee ee ey i ee nmigripes Wied. Wings with a smoky tinge; costal cell heavily colored; large species — with median triangles small or obsolete and with subcallus always pollinose \.2 0 ee 24. Pore tibiae bicolored ]. 20. We eee novaescotiae Macq. Fore tibiae unicolovous: 4: >= ae eee Pe i.e. 25. Third antennal segment reddish yellow; median abdominal triangles — faint and arising from faint posterior bands; first posterior cell narrowed toward marein 24.0 oo ee calens L. Third antennal segment partly black; median triangles small but distinct and not arising from bands; first posterior cell not narrowed Fee Pee eC hen mite tin Se ian tea OR MaMa Be oe TE halos catenatus Wk. mye Key to the Species of Ontario Tabanus — Males L. Eyes hairy ee Se 2 Fiyes bare.) 0 a oy ae ae 4 Dat WINS BPOLE 50 Wate ee eee Rae ees reinwardtu wg Bifurcation of third longitudinal vein with a dark spot; grayish Wings unspotted ecu Nee ee, 10. fl. 2. 13. 14. 15. 16. Abdomen with a conspicuous parallel-sided median longitudinal white stripe and a similar stripe on each side of it .. vittiger schwardti Philip Abdomen without a conspicuous parallel-sided median stripe .............. PE emer et ir oc ype Ae elu BN aon farchildi Stone Abdomen unicolorous or with narrow indistinct pollinose bands .... 5 POUoMmen with median markings: 0). cee ee 9 EMO CamererbLrowmn “tO: Yellow: -.6 oo. Re ee 6 Heel Ole Ca Ke OMOWMbOrDIACK 42000 eee | Se a i Wing dilutely infuscated, costal cell darker; hind tibial pee Dees cen og 2c 2 AEG anL sa 8 MERI GAL Sa fe aaa Maleate ROTI ppc aac get ROE te calens L. Wing hyaline; costal cell deep yellow; hind tibial fringe orange........... ee nr ee Ny al ly bd americanus Forster WpeMGMONACKt agit te se a ae atratus Fab. Wings dilutely infuscated or clear, a black spot at bifurcation of third OMINOUS a a a a Oe 8 Lower margin of area of large facets of eye somewhat sinuate and at lowest point about on level with top of antennal pits .... subniger Coqu. Lower margin of large facets more nearly straight and somewhat Mmuy@er pnaneamvemnal DltS: 4... ee. stygius Say . Abdomen with a longitudinal stripe which may or may not be some- what widened at posterior margins of segments ..................00.00008. 10 Abdomen with median markings not forming an uninterrupted sa Lateral markings of abdomen forming a stripe on each side of median stripe and parallel to it but usually shorter than median stripe; spots DEMS median Stripe nearly parallel-sided’....0...8.0 2.2... ligt Lateral markings broken into separate often roundish spots; spots forming median stripe usually wider at posterior margin of each SED STIG se ee eter Uke ane it ane OAC ea eoettecs Prenat 13 Prescutal lobe usually concolorous with mesonotum; annulate portion of third antennal segment as long or longer than basal portion; costal cell heavily infuscated; palpi deep yellow ..... quinquevittatus Wied. Prescutal lobe usually paler than mesonotum; annulate portion of third antennal segment usually shorter than basal portion; costal cell meine Oileawntish. 9. 2. fk ees ee ee ee a 12 ee ee a ae similis Macq. Hair of thoracic dorsum gray; sublateral abdominal spots grayish; CoOspalnecell hyaline’ palpi White. 702) = sackent Fairchild At least short hairs of thoracic dorsum vellow; sublateral abdominal spots yellow; costal cell tinted; palpi yellow ....................... sagax O.S. Abdomen with median spots or triangles and at least some tergites AVItE Sublateral, Spots: 2.5.64. Sees es ll OR oe Ue Paes Se RR ele Abdomen with median spots or triangles; no distinct sublateral spots although some tergites may be paler laterally 0.00.0 20 First antennal segment swollen above; third antennal segment entirely black; eyes sometimes with sparse hairs ............ .... fairchildi Stone First antennal segment not swollen; third antennal segment variable; COA eee re ig at NS aR Re ras a Be ue NR PE a 16 Fore tibiae entirely black; sublateral spots very large often crossing second and third tergites; third antennal segment black ...... ............ sicilgile ee sotaeebe ci No NRO c-Si a ate Me ae POT Near ah RU A marginalis Fab. 17. 18. 19. 20. Dole 22; 23. 24. 25. Fore tibiae paler at base; sublateral spots smaller rarely crossing any tergite; third antennal segment not eHUIne y: black =)... 4 Moderate sized species; 14-15 mm.; second palpal segment yellow brown, about twice as long as wide; median triangles fairly large, sometimes crossing tergite; sublateral spots reaching posterior mar- gin of at least second tergite; costal cell somewhat tinted .... vivax O.S. Small species, usually under 11 mm.; second palpal segment whitish, less than twice as long as thick; median triangles small, never crossing tergite; sublateral spots small rarely reaching posterior margins of tergites: costal ‘cell: hyaline... ea ae 18 Tibiae same color as reddish brown to brown femora or slightly paler basally; antennae yellowish, often with annulate portion somewhat darker; basal portion of third antennal segment two and one half to three times as long as wide; occipital tubercle prominent and often projectins above Jevel:of eyes -2o ia. et ee pumilis Macq. Tibiae distinctly paler than dark femora except apex of fore tibia which is dark; antennae uniformly dull brownish; basal portion of third antennal segment about twice as long as wide; occipital tubercle inconspicuous and compressed, usually not reaching level of eyes 19 Eyes in: life: without: Stripes:.(: =e een er ee ee sparus Whitn. Eyes in life with a single purple stripe ............ sparus millert Whitn. Pale thorax sharply contrasting with dark abdomen which has distinct white median triangles on the third to fifth tergites; fore tibiae . bicelored: 2 heer ee ee trimaculatus Palisot Not with the above. combination of characters = > 3) ee Wins SHOtbed: te oad eee pe EE a ae sulcifrons Macq. Wings. unspotted. 3.40500 2S Se ee 22 Frontal triangle denuded and somewhat protuberant; abdominal triangles often indistinct; smaller species usually under 13 mm. ......... HOG hE Es Sip 2 arsine ce) eke ee ee nigripes Wied. Frontal triangle not denuded; larger species, rarely smaller than 15 mm. andias larve as 25 mm..2).. 20 6 ee Ze Facets of eyes all about same size; median abdominal triangles very Smad bee hee Nee es ee eee oy ee ee -colens Ta: Upper facets of eye larger than lower facets with line of demarcation GISHINCE. 2 eS ee as 24 Median triangle usually absent from tergite 2 or very small if present; large eye facets occupying about half total eye area; femora dark DROW Or OIA Cas oe een! i cae ea ene superjumentarius Whitn. Median triangle present on tergite 2 and about same size as those on tergites 3 and 4; large eye facets occupying about two thirds of total eye area; femora orange brown to chestnut brown .......................... 25 Legs almost uniformly brown, tarsi somewhat darker; genae brown; second palpal segment brown; abdomen uniformly dark brown with small median trancles: 3 aa on ee a catenatus W1k. Middle and hind tibiae and base of fore tibiae paler than femora; genae grayish; second palpal segment yellow brown; abdomen red- dish brown laterally with median triangles on a narrow black stripe novaescotiae Macq. Tabanus americanus Forster Large (27 mm.) ; reddish brown; abdomen with narrow pale bands on hind margins of tergites; wings hyaline with dark 114 brown costal cell; eyes bare. Male eye facets distinctly differenti- ated; eyes bare. Ontario Records—Essex, July 6; Kent; Huron, July 15-17; Carleton, July 6-17. Tabanus atratus Fabricius Large (24 mm.) ; black; abdomen sometimes with a whitish or bluish bloom; eyes bare; wings dark brown to black. Male eye facets distinctly differentiated; eyes bare. Ontario Records—EHssex, June 24-July 18; Kent, June 7-July 25; Middle- sex, June 20-Aug.; Norfolk, June 18-Aug. 17; Oxford, Aug. 19; Brant, Aug.; Lincoln, June 20-Aug. 7; Wentworth, June-July 27; Perth, Aug. 1; Wellington, July; Peel, Aug. 22; Grey; Simcoe, July 15-Aug. 28; York, Aug. 6; Hastings, June 26-Aug. 20; Lanark, Sept. 9; Carle- ton, Aug. 14; Russell, July ; Stormont. *Tabanus calens Linnaeus Large (24 mm.); thorax brown with indistinct reddish lines; abdomen blackish, sometimes with faint pale median triangles; eyes bare; wings pale yellowish with costal cell darker. Male eye facets show little differentiation and line of demarcation not dis- tinct; pale median triangles of abdomen when present usually larger than in female; eyes bare. Ontario Records—Kent, Aug. 12-20. | { dd tail eat Tabanus catenatus Walker Large (23 mm.) ; dark reddish brown; abdomen with a median row of small pale triangles; fore tibiae entirely brown; wings pale yellowish, often darkened anteriorly along veins, costal cell deep yellow; eyes bare. Male eye facets distinctly differentiated ; thorax and abdomen from reddish brown to very dark brown; median row of abdominal triangles often indistinct; eyes bare. Ontario Records—Lincoln, July 17-Aug. 29; Wentworth, July-Aug. 20; Wellington, Aug. 9-12; Peel, Aug.; York, July; Simcoe, July 28; Durham, July 12; Hastings, July 10-Aug. 1; Grenville, July 27; Carleton, July 18-Aug. 8. Tabanus farrchildt Stone Moderate in size (14 mm.) ; blackish brown with three rows of pale spots on abdomen; antennae black with first segment swollen above; eyes bare or with short scattered hairs; wings hyaline. Male eye facets somewhat differentiated but line of demarcation not distinct; eyes often with short scattered hairs but sometimes apparently bare. : Ontario Records—Wellington, July; Peel, July 7; Cochrane, Aug. 9. Tabanus fulvicallus Philip Moderate in size (14.5 mm.) ; dark brown; abdomen with 3 rows of pale spots with median spots reaching length of tergite on third to fifth segments; vertex notched and somewhat swollen; third antennal segment dark brown to black with last annulus orange brown; wings hyaline; eyes bare. Ontario Records—Essex, June 29-July 6; Parry Sound, July 20. 115 Tabanus lineola Fabricius Moderate in size (13 mm.) ; yellowish, brown or nearly black; abdomen with a pale median stripe and variable sublateral stripes; wings hyaline; frons narrow and distinctly widened above; median callus slender ; hind femora mostly dark; scutellum entirely dark; eyes bare. Male eye facets distinctly differentiated ; eyes bare. Ontario Records—Essex, July 16; Norfolk, June 15- Aug. 23; Lincoln; Wentworth, July 1-31; Brant; Wellington, July 11-Aug. 29; Peel, July 19; York, Aug. 18; Simcoe, ‘July 8-22; Hastings, June 28- Aug. 18; Leeds, J uly 20-24 ; Grenville. Tabanus marginalis Fabricius (= nivosus O.S.) Moderate in size (138 mm.); blackish brown; abdomen with 3 rows of pale spots, the median row being much smaller than the sublateral rows; wings hyaline; eyes bare. Male eye facets dis- tinctly differentiated ; sublateral abdominal spots of even greater extent than in female; eyes bare. Ontario Records—Essex, June 19-July 11; Huron, June 27; Waterloo, June-July; Wellington, June 12-July 14; Simcoe, July 22-25; North- umberland, July 24; Peterborough, July 3; Hastings, July 3-24; Len- nox and Addington, Aug. 18; Frontenac, Aug. 8; Carleton, June 12-18; Muskoka, June 22-Aug. 16; Parry Sound, June 28-Aug. 27; Nipissing, June 28-Aug. 11; Sudbury, July 1-Aug. 6; Manitoulin, Aug.; Algoma, Aug. 4-21; Cochrane, June 27-July 17; Thunder Bay, July 13-Aug. 18; Kenora, July 26. Tabanus nigripes Wiedemann Small to moderate in size (12 mm.) ; blackish brown; abdomen with a median row of pale triangles and tergites with narrow pale bands on the hind margins; wings hyaline, occasionally with traces of spots and yellow costal cell; subcallus thinly pollinose or partly denuded; eyes bare. Male eye facets distinctly differen- tiated ; frontal triangle prominent, denuded; eyes bare. Ontario Records—Muskoka, July 2-Aug. 16; Parry Sound, July 7-23; Nipissing, July 8-12. = *Tabanus novascotiae Macquart (= actaeon O.8.) Fairly large (20 mm.) ; reddish brown with thorax sometimes fuscous; abdomen with a median dark longitudinal band which may be broad and distinct or nearly obsolete and a median row of small pale triangles; basal half of fore tibiae yellowish; wing hyaline or faintly tinged with yellowish especially in the costal cell; eyes bare. Male eye facets distinctly differentiated; eyes bare. Ontario Records—Brant, Aug.; Hastings, Aug. 20; Lennox and Adding- ton, Aug. 7-14; Parry Sound, July 20-27; Nipissing, Aug. 10; Mani- toulin; Algoma, Aug. 16. Tabanus pumilus Macquart Small in size (9.5 mm.) ; dark brown to grayish black; abdomen with a row of faint median triangles and roundish sublateral spots; median callus subquadrate; second palpal segment rather slender and apex not sharply pointed; frons somewhat widened 116 above; wings hyaline; eyes bare. Male eye facets distinctly differentiated; occipital tubercle conspicuous; eyes bare. Ontario Records—Elgin, June 25; Norfolk, June 15-Aug. 23; Lincoln; Wentworth, June 22-Aug, 19; Waterloo, July 9-16; Wellington, June 8-July 22. Tabanus quinquevittatus Wiedemann Moderate in size (12.5 mm.) ; yellowish; abdomen with a yellow median stripe bordered with black, lateral margins usually yel- lowish; pollen of head yellow; wings hyaline with a dark yellow costal cell; frons with sides essentially parallel; eyes bare. Male eye facets distinctly differentiated; eyes bare. Ontario Records—Essex, July 8-14; Kent, June 17-July 9; Lambton, June 24-July 17; Middlesex, June 28-Aug. 18; Elgin; Norfolk, June 15-Aug. 23; Welland, July; Lincoln, June 28-Aug. 31; Wentworth, June 7-Aug. 31; Wellington, July 3-Sept. 15; Waterloo; Perth, July 19; Huron, June 28; Bruce, July 10-Aug. 3; Dufferin, July 15; Simcoe, June 29-July 28; Peel, July 8; York, July 21-Aug. 7; Peterborough, Aug. 8; Hastings, June 22-Aug. 20; Northumberland, July 17-24; Prince Edward, July 16; Lennox and Addington, Aug. 13; Frontenac, July 3-Aug. 18; Carleton, July 14; Muskoka, June 26-Aug. 9; Parry Sound, July 20-28. Tabanus reinwardtu Wiedemann Moderate in size (17 mm.) ; grayish black; abdomen with gray median triangles and larger pale sublateral spots; basal callus large and shining; frons broad and essentially parallel sided; wings spotted with brown; eyes bare or with short scattered hairs. Male eye facets somewhat differentiated but line of demarcation not distinct; eyes hairy. Ontario Records—Elgin, June 16; Norfolk, July 9; Middlesex, July 18; Lincoln, July 22; Wentworth, July 17-Aug. 4; Waterloo, July 16; Wellington, July 2-24; Bruce, July 20; York, July 2; Hastings, July 7-24; Frontenac, July 15; Leeds, Aug. 10; Carleton, July 24; Nipis- sing, July 4-26; Parry Sound, July 20-21; Sudbury, July 4-20; Mani- toulin, Aug. 5; Algoma, Aug. 21; Cochrane; Thunder Bay, July 13; Patricia, July 16. Tabanus sagax Osten Sacken Moderate in size (14 mm.); orange brown; abdomen with a median line of contiguous triangles and rather indistinct sub- lateral spots; frons parallel sided and quite broad; third antennal segment, variable but usually slender, dark orange with annuli black; second palpal segment swollen; wings hyaline; eyes bare. Male eye facets distinctly differentiated; eyes bare. Ontario Records—Sudbury, July 20. Tabanus similis Macquart (= lineola scutellaris Walker) Moderate in size (13 mm.) ; brownish to almost black; abdomen with a pale median stripe and sublateral stripes; wings hyaline; frons broader than in typical form, widened above; median callus somewhat broadened; hind femora reddish; scutellum red- dish brown at tip; eyes bare. Male eye facets differentiated but size difference is small and line of demarcation often indis- tinct; general color usually brownish; eyes normally bare but sometimes with a few scattered hairs. 117 Ontario Records—Essex, June 28-July 9; Kent, July 13-16; Lambton, June 12; Elgin, Aug. 3; Norfolk, June 6-Aug. 23; Lincoln, July 3-24; Went- worth, June 21-Aug. 11; Halton, June 21; Waterloo, July 16; Welling- ton, June 17-Aug. 15; Perth, July 19; Huron, July; Bruce, July 10-Aug. 19; Dufferin, July 15; Peel, July 6-17; Simcoe, June 5-Aug. 9; York, June 11-July 20; Victoria, June 27; Northumberland, July 17; Hastings, June 7-July 29; Grenville, June 12-28; Carleton, June 5-Aug. 8; Renfrew, Aug. 3; Parry Sound, July 24; Sudbury, July 11-23; Manitoulin, Aug. 5; Algoma, June-July 12. Tabanus stygius Say Large (22 mm.) ; pile of thorax grayish white; abdomen black; frons brown and rather narrow; wings yellowish with dark spots, costal cell deep yellow; eyes bare. Male eye facets distinctly differentiated; pile of thorax dark brown; third antennal seg- ment dark orange; eyes bare. Ontario Records—Essex, July 19; Middlesex, July; Norfolk, June 15-Aug. 23; Lincoln, June 29-July 29; Wentworth, July 30-Aug. 4; Wellington, July 12. Tabanus subniger Coquillett Large (23 mm.) ; pile of thorax grayish white; abdomen black; eye normally bare; wings pale yellowish with dark spots, costal cell yellow; frons broad and gray, narrowed above and notched at vertex. Male eye facets distinctly differentiated; pile of thorax tle brown; third antennal segment dark brown or black; eyes are. Ontario Records—Peel, June 16. Tabanus sulcifrons Macquart Fairly large (21 mm.) ; reddish brown; abdomen with a median row of pale rather broad triangles and hind margins of tergites with pale bands which broaden laterally ; fore tibiae pale at base; wing somewhat tinted, with dark spots and dark yellow costal cell; eyes bare. Male eye facets distinctly differentiated; eyes bare. - Ontario Records—Essex, July 26; Welland, July 21-Aug. 7; Lincoln, July 31-Aug.; York, July 30. *Tabanus vivax Osten Sacken Moderate in size (14.5 mm.); dark blackish brown; abdomen with 3 rows of pale spots, the median triangle on second tergite not reaching the anterior margin; wings hyaline; eyes bare. Male eye facets distinctly differentiated; eyes bare. Ontario Records—Norfolk, June 22-26; Wellington, June 12; Muskoka, June 26; Hastings, July 17. SOME COMMENTS ON THE TABANIDAE OF THE WHITESHELL AREA OF MANITOBA Through the co-operation of Prof. A. J. Thorsteinson and Mr. Garth K. Bracken of the University of Manitoba, one of the writers (Pechuman) was able to study over 2000 specimens of Tabanidae taken in the White- 118 shell area of Manitoba in 1959. These were collected in six Thorsteinson Heliothermal Traps set up at three localities within the Whiteshell area. The geology, soil and forest types of this area are those of adjoining Ontario and Minnestota and quite distinct from that of Manitoba lying directly to the west. It is not surprising, therefore, that the tabanid fauna is also closely related to that of the adjoining portions of Ontario and Minnesota. It seems appropriate for this reason to list the Tabanidae included in the above collection with earliest and latest collection dates since these records help support the somewhat meager collection records from that part of Ontario lying directly to the east. Chrysops dawsoni Philip, June 29. Chrysops excitans Wlk., June 17-July 31. Chrysops frigidus O.8., June 29-August 18. Chrysops furcatus Wlk., July 9-July 15. Chrysops indus O.S., June 29-July 31. Chrysops mitis O.S8., July 9-July 31. Chrysops montanus O.S8., July 14-August 24. Chrysops nigripes Zett., July 9-July 31. Chrysops sackeni Hine, July 19-July 23. Chrysops venus Philip, July 9. Haematopota americanus O.S., July 14. Hybomitra affinis (Kirby), June 17-July 29. Hybomitra arpadi (Szil.), July 9-July 23. Hybomitra epistates (O.S.), June 17-August 6. Hybomitra frontalis (Wlk.), July 9-August 17. Hybomitra illota (O.8.), June 8-July 29. Hybomitra lasiophthalma (Macq.), June 8-July 31. Hybomitra metabola (McD.), June 9-July 15. Hybomitra microcephala. (O.S.), July 19. Hybomitra nuda (McD.), June 9-July 15. Hybomitra trepida (McD.), July 9-August 6. Hybomitra typhus (Whitn.), June 24-August 15. Hybomitra zonalis (Kirby), June 29-July 23. Tabanus fulvicallus Philip, July 19. Tabanus marginalis Fabr., June 9-August 6. Tabanus similis Macq., July 29. Of the species listed above, the following have not previously been reported from Manitoba although all are common in Ontario (except T. fulvicallus of which only a few specimens are known) : Chrysops dawsoni, indus, montanus, sackeni and venus, Hybomitra microcephala and typhus and Tabanus fulvicallus. The Whiteshell area probably represents the ex- treme northwestern range for all of these species except H. typhus. Since records from localities directly north of Lake Superior are lacking for Chrysops indus and montanus, Hybomitra microcephala and Tabanus ful- vicallus, it is probable these species have entered the Whiteshell area directly from Minnesota or indirectly by way of Rainy River and Kenora. Tabanus similis, which was represented by a single specimen, has not been reported north of Lake Superior but is very abundant in Manitoba west of the Whiteshell area. It is probable that both Chrysops furcatus and nigripes have entered this area from the north or are relict populations. 119 (1) (2) (3) (4) (5) (6) (7) (3) (9) (10) (11) (12) (13) (diz) (15) (16) (17) (18) (19) (20) (21) REFERENCES BRENNAN, J. M. (1935). The Pangoniinae of Nearctic America (Tabanidae, Diptera). Kansas Univ. Sci. Bull. 22: 249-401. CAMERON, E. A. (1926). Bionomics of the Tabanidae (Diptera) of the Canadian Prairie. Bull. ent. Res. 17: 1-42. DAVIES, D. M. (1959). Seasonal variation of tabanids (Diptera) in Algonquin Park, Ontario. Canad. Ent. 91: 548-553. JAMNBACK, H. and WALL, W. (1959). The common saltmarsh Tabanidae of Long Island, New York. Bull N.Y. State. Mus, Sci. DEEV, 375). 1-11. Jupp, W. W. (1949). Insects collected in the Dundas Marsh, Hamil- ton, Ontario, 1947-48. J. N.Y. ent. Soc. 87: 225-231 (tabanids p. 227). JUDD, W. W. (1958). Studies of the Byron Bog in southwestern Ontario. V. Seasonal distribution of horse flies and deer flies (Tabanidae). Canad. Ent. 90: 255-256. MACKERRAS, I. M. (1954). The classification and distribution of Tabanidae (Diptera). Aust. J. Zool. 21: 431-454. MARCHAND, W. (1920). The early stages of Tabanidae (horse flies). Monogr. Rockefeller Inst. med. Res. 13: 1-203 (186 figs.). OSTEN SACKEN, C. R. (1825-1878). Prodrome on a monograph of the Tabanidae of the United States. Parts I and II. Mem. Boston Soc. Nat. Hist. 2: 421-479, 555-560. PECHUMAN, L. L. (1957). Some Tabanidae (Diptera) not previously recorded from Canada. Rep. ent. Soc. Ont, 87: 27-28, 1956. PECHUMAN, L. L. (1957). The Tabanidae of New York. Proc. Rochester Acad. Sci. 10: 121-179 (88 figs.). PECHUMAN, L. L. (1960). Some new and little-known North Ameri- can Tabanidae (Diptera). Canad. Ent, 92: 793-799. PHILIP, C. B. (1931). The Tabanidae of Minnesota. Tech. Bull. Minn. agric. Exp. ota. 601-128 (Ai hios.)): PHILIP, C. B. (1941). Comments on the supra-specific categories of Nearctic Tabanidae (Diptera). Canad. Ent. 73: 2-14. PHILIP, C. B. (1947). A catalog of the blood-sucking fly family Tabanidae of the Nearctic region north of Mexico. Amer. Midl. Nat. 37 2 2DI-o2A. PHILIP, C. B. (1950). Corrections and addenda to a catalog of American Tabanidae (Diptera). Amer. Midl. Nat. 43: 430-437. PHILIP, C. B. (1954). New North American Tabanidae (Diptera). VI. Descriptions of Tabaninae and new distributional data. Ann. ent. Doc. Amer. 2/5) 20-00. PHILIP, C.B. (1954). New North American Tabanidae. VIII. Notes on and keys to the genera and species of Pangoniinae exclusive of Chrysops. Rev. Brasil Ent: 2: 13-60. PHILIP, C. B. (1955). New North American Tabanidae. IX. Notes on and keys to the genus Chrysops Meigen. Rev. Brasil Ent. 3: AT AZS. PHILIP, C. B. (1959). New North American Tabanidae. X. Notes on synonymy, and description of a new species of Chrysops. Trans. Amer. ent. Soc. 85: 193-217. SCHWARDT, H. H. (1936). Horseflies of Arkansas. Bull. Ark. agric. Exp. Sta. 932: 1-66. 120 (22) STONE, A. (1930). The bionomics of some Tabanidae (Diptera). Ann. ent, Soc. Amer. 23: 261-304. (23) STONE, A. (1938). The horseflies of the subfamily Tabaninae of the Nearctic region. U.S. Dep. Agric. Misc. Publ. 305: 1-171. (24) TESKEY, H. J. (1960). Survey of insects affecting livestock in south- western Ontario. Canad. Ent. 92: 531-544. (25) WEBB, J. L. and WELLS, B. W. (1924). Horseflies: Biologies and relation to western agriculture. Bull. U.S. Dep. Agric. 1218: 1-36. THE MOSQUITOES OF ONTARIO (DIPTERA: CULICIDAE) WITH KEYS TO THE SPECIES AND NOTES ON DISTRIBUTION C. C. STEWARD and J. W. MCWADE' CONTENTS Page RUE CNC TON erm ee eC tes Peru ar Tere als ek Ve ee IAL Mer MUO Te MeMeia ey 123 Genera Minopheless Meigen | fo ee Rete Mar BeBe pce Saxe! 125 Ve OniG MmMeO OR ts Oe PE Oe ee ae ey 130 Dronorocnia lnyneneA pripalzagas 6 ee a 130 COIS CUO INC Oe ee eran nd Nove oe ey eh Rye Lo VAGTESOMETOR: MATACIMAT Cis ai ee Ma Dy es aN de a 134 Psorophora Robineau-Desvoidy .......-...0.0.0000.000.0.000000... UI a See ae 135 Aedes Meigen Oe ht evi I tute eae te os ko s,s os ah 136 OC ete MIA CUISs etre eee eo SUMMA een ie le mn ee Nim ima ke ee 161 PCI SMONMICOOCMMCMItS ae en ee eh ee 161 Bibliography <0. RUE Opie hoa teenie os. dS Tem GRIN 8 We 162 INTRODUCTION Apart from some earlier local and sporadic collectors the first entomo- logist to give an account of the mosquitoes of Ontario (chiefly as part of a study embracing the whole of Canada) was Dyar (6). Since then a number of workers (see bibliography) have published useful local lists and accounts of field work, while the efforts of the Northern Insect Survey have contributed a great deal to our knowledge of the mosquito fauna of the most northerly parts of the province. The present paper is an attempt to assemble the information now available about Ontario species of Culicidae. The existing literature has been consulted and use made of the insect collections of the Department of Agriculture Entomology Laboratory at Guelph, and of the Ontario Agricultural College, Guelph. i—ntomology Laboratory, Canada Department of Agriculture, Guelph, Ontario. Proc. ent. Soc. Ont. 91 (1960) 1961 121 In the keys and descriptions of species only those characters which may be useful in identification are stressed and these are often shown by arrows in the figures. Thus, in the genus Aedes there is little point in Proboscis ok -_ Antenna HEAD C\ Vertex 5 ANOPHELES 2a Antescutellar Area Anterior Pronotal Lobe THORAX Scutum Mesonotum 4 Scutellum Postnotumé Femur ABDOMEN ANOPHBEES Witt} J AN \ WA eS [PARBDES 2 WS INS AEDES Scutellum 6 Fig. y¥ Ves ey 4 5) AEDES % Fig. 2. Anopheles female head. Fig. 4. Aedes male head. Figs. 5 and Fig. 1. Diagram of Aedes female. 3. Culex female terminal segment. 6. Scutellum of Aedes and Anopheles. | 122 describing for each species the occiput with its seldom varying scales and setae, or the patches of gray scales on the pleura which are present in so many of those listed. For full descriptions of the species with North American distributions and biological notes, the reader is referred to Carpenter and La Casse’s excellent work (4). The importance of using teneral unrubbed adults for identification must be stressed. Even here reliance cannot always be placed on the “golden brown” or “yellowish brown” of many of the descriptions of the scutum for, as Beckel and Atwood (3) point out, these and other scale areas may change in colour during the season in the same species. This applies particularly to the median stripe or stripes, usually darker in colour than the rest of the scutum, but variable and uncertain in so many species. 2 If males are available identification of the species is greatly facilitated. Moreover, the possession of males usually means they were reared from larvae and in this case still an additional stage is available. The worst situation is where only net-caught rubbed or damaged females are avail- able as is so often the case when specimens are sent in for identification, and in this event, final reference to species may be impossible (see remarks on Aedes below). KEYS TO THE GENERA The following key and figures should separate the genera (of which there are eight in Ontario) without difficulty. Usually the characters given for adults are common to both male and female. A low-power binocular microscope is practically essential in this work. It is well to keep in mind that mosquitoes flying in any numbers during early summer are nearly always Aedes spp. Because of the practical purpose of this paper and the small geogra- phical area involved subfamilies are ignored and the species are described in alphabetical order in we respective genera; in general the figures are Similarly arranged. ADULTS 1. Abdomen without scales. Scutellum rounded (Fig. 6). Female palps Metcivmas Jong as proboscis (Hig.2) 2... Anopheles Abdomen densely scaled. Scutellum trilobed (Fig. 5). Female palps SiG SEE 6 TR se a os 08 en Ree 2 2. Second marginal cell of wing short, less than half as long as the petiole (Fig. 8). Very small mosquitoes .....00000000...0000.. Uranotaenta Second marginal cell of wing as long as or longer than the petiole 3 3. Postnotum with a tuft of setae (Fig. 29). Wing squamae without a MIO Ol NaIhe a A ee Se a Ne ee Wyeomyia oun without a tuft of setae. Wing squamae with a fringe of ENTS jel Gstaad oer aiO ane Nate Ca aR SEs grees Pa Nee Wachee spare icin A a fee spiracwiar bristles present. (Fig: 7) ...005.0 000 ee eek. ORO 5) SRA Culat ObISUICS ADSEMt! ee Sen ei Ne ay en tae 6 5. Postspiracular bristles present (Fig. 7) Tip of female abdomen [OSC IEA CEG ieee ENN es Es SS As ee pe ae ee Cem cn Re Psorophora Postspiracular bristles absent. Tip of female abdomen blunt or WOMEN Ocenia 1 A eee a Dee cs Shey LA poms Culiseta 6. Postspiracular bristles present. Tip of female abdomen Os BE Re ESN pS eS aie ee RU Oa hd Peace OTA a inn Ee re edes Postspiracular bristles absent. Tip of female abdomen blunt .......... Hi 123 2nd Marginal Cell ‘Fr Ww wre vi mw we Fig. 7. Lateral view of generalized mosquito thorax. hs, hypostigial scale patch. Ime, lower mesepimeral bristles. pa, prealar bristles. pcs, postcoxal scale patch. ppn, postpronotal bristles. psp, postpiracular bristles. ae re bristles. stp, sternopleural bristles, ume, upper mesepimeral ristles. 1, pronotum. 2, proepisternum. 3, postpronotum. 4, mesanepister- num. 5, sternopleuron. 6, mesepimeron. 7, metepisternum. 8, prealar’ area. 9, postnotum. 10, scutellum. 11, meteusternum. 12, scutum. 13, ab- domen. 14, head. 124 7. Wing scales broad, brown and white mixed, Proboscis with median wide white ring. Hind tarsi with broad white bands. ........ Mamnsonia Wing scales narrow and dark. Proboscis and tarsi without broad TALUS GS ENTG ISVS: Se eo al eee ie ae ee ad NR PRE SEN a aes Culex LARVAE (FOURTH INSTAR) fee etic Heopresent: CRIGt Zo) Soe ee 2, EemmEMOC OSEMG.(CHIG Fo) oe. ee She eh Anopheles 2. Air tube short, pointed or sub-conical (Fig. 81) .................... Mansonia Pee LONS CVC Cal ores ee ne oe ey Sy ee 3 Pee Meni OC Whirl MeCuen 285 25 18 i Ue ee, ae 4 Paeroe WILhOUL pecten CRIS. "(8) eae aa W yeomyta 4. Head longer than wide; eighth abdominal segment with strongly sclerotized plate bearing a comb (Fig. 80) .........0...00000...... Uranotaenia Head at least as wide as long; eighth abdominal segment without a sclerotized plate (small, weakly sclerotized plate in Psorophora) 5 5. Air tube with pair of large basal Weets AGERE A el Le abe ates Culiseta een withOul basal GULLS o. fe oe ee ek 6 6. Air tube with several pairs of tufts or single hairs laterally or ventrally along its length. (N.B. Aedes trichurus, Fig. 131, has several pairs of dorsal tufts similarly arranged) ........................ Culex Air tube with one pair of median or sub-apical tufts, or one pair of IPM ERS te ee he ee a ee a a 7 7. Anal segment completely ringed by saddle and pierced on mid-ventral ime yes oF ventral brush (Fig. -82) 22.24.23... ose. Psorophora Anal segment not completely ringed by saddle, or if so ringed, saddle not pierced along mid-ventral line by ventral brush .................... Aedes Genus ANOPHELES Meigen This is largely a tropical and sub-tropical genus. Four species are recorded from Ontario. Among generic characters are: The female palps (Fig. 2), usually as long as those of the male; the spotted wings; the presence of hairs instead of true scales on much of the abdomen; the scutellum evenly curved on its posterior margin (Fig. 6) ; the two promi- nent elevated spines on the male basistyle; and the absence of air tube in the larva. Identification of the adults is generally not difficult. The larvae however have few distinguishing specific points; the inner clypeal hair, (2), (Fig. 72) seems to be a reasonably constant character and is used in Fig. 8. Mosquito wing showing venation. Veins are numbered accord- ing to the Loew system, with the Comstock-Needham notation following in brackets. A, alula. C, costa. SC, subcosta. H-V, humeral crossvein. 1, first longitudinal vein (R 1). 2.1, anterior branch of second longitudinal vein. (R 2). 2.2, posterior branch of second longitudinal vein (R 8). 3, third longitudinal vein (R 4 + 5). 4.1, anterior branch of fourth longi- tudinal vein (M 1 + 2). 4.2, posterior branch of fourth longitudinal vein (M 3). 5.1, anterior branch of fifth longitudinal vein (Cu 1). 5.2, posterior branch of fifth longitudinal vein (Cu 2). 6, sixth longitudinal vein (2 A). 2-3 (r-m), 3-4 (i-m) and 4-5 (m-cu), crossveins. PT, petiole of 2nd longi- tudinal vein. S, squama. 125 the following larval key. In the adult male the spine on the dorsal (extern- al) lobe of the claspette is useful as is the shape of the lobe of the ninth tergite, but both these characters are subject to variation and individuals with intermediate types are occasionally found. Most of the characters listed for the female can be used for the male. us DS: Fig. 9. Diagram of male terminalia of a mosquito, AL, apical lobe. AM, anal membrane. BL, basal lobe. BP, basal plate. BS, basistyle. C, claw of dististyle. CL, claspette stem. DAS, dorsal arm of tenth sternite. DS, dististyle. F, claspette filament. IF, interbasal fold. 9T, ninth tergite. 9TL, lobe of ninth tergite. P, paramere. PH, phallosome. 10S, tenth sternite. 126 KEYS TO THE SPECIES FEMALES 1. Wings with patches of white scales. Wing veins 3 and 5 dark scaled =A ibe SHOE Se ce A aE OG cana UN Ie eR LORS Ea Ra punctipennis KVaniosrentuinely dark SCALCU so. 0) i iy eae oe 2 2. Tip of wing with a silver- or copper-coloured fringe .................... earler iyo wink wathout a paleriringe, 0) ee es ee a ae. 3 3. Segments of palps with narrow white apical rings .................. walkert Segments of palps without apical rings ...................... quadrimaculatus MALE TERMINALIA Tf, foe oe spines of dorsal lobe of claspette bluntly rounded at Apes HOO err oes ere Eee Med MN ieee be CN Cag Uh 1M tO ibs External spines of dorsal lobe of claspette pointed at apex (Fig. 25) 2. One or more leaflets of phallosome sah teeth at base (Fig. 24). or of ninth tergite constricted in middle, widened and rounded apically ; dorsal lobe of claspette (Fig. 26) with 1 to 5 blunt spines often OMA TUSCAN ee rena Oe i ee quadrimaculatus Leaflets of phallosome without basal teeth; lobes of ninth tergite narrow, tapering or rounded apically, but not widened; dorsal lobe of elaisperverwith dor: 2 blunt spines (Figw27) —.o90000.0..000 8 walkert 3. Lobes of ninth tergite wide and short, with apex expanded. Dorsal lobe of claspette usually with 2 or 3 pointed spines (Fig. 25) .... earlei Lobe of ninth tergite narrow and long (Fig. 24). Dorsal lobe of Claisperte: with’ or 2 pointed spines 7.2.6. punctipennis LARVAE (FOURTH INSTAR) 1. Inner clypeal hairs (2) (Fig. 72) branched ........................ Risa gy ose: 2 innmnerxehy peal mains. (2) simples. Fk he ye aes 3 are inner ely peal hairs (2) simply forked (Fig. T4) .......4.5.40.0.2 earlea Inner clypeal hairs (2) sparsely and minutely feathered towards tip (LEB, OT) i BOO Gen a SAR Le ae At Ag Ae at SNR eS ee em walkeri 3. The basal tubercles of the inner clypeal hairs (2) separated by at least the diameter of one tubercle (Fig. 76) ................ quadrimaculatus The basal tubercles of the inner clypeal hairs (2) separated by less than the diameter of one tubercle (Fig. 75) .................. punctipennis Anopheles earlet Vargas FEMALE. A large species; wing length 5.0 to 5.5 mm. Proboscis dark brown. Palps about same length as proboscis, dark brown. Scutum yellow, with a median grayish stripe. Scutellum crescent-shaped, covered with yellow hairs and brown setae. Wing with groups of dark scales forming a Spots; the extreme tip with a clear silvery or coppery spot. Tarsi ar MALE. The pointed spines of the dorsal lobe of the claspette (Fig. 25) and the shape of the ninth tergite, taken together are reliable points and will usually serve to separate the species from the three others of the genus. LARVA (Figs. 73 and 74). Inner clypeal hairs (2) with 2 to 5 branches; these hairs usually separated at their bases by the width of one tubercle. Postclypeal hairs (4) with an average of 4 or more branches. 127 DISTRIBUTION. This species was formerly confused with A. occi- dentalis and A. maculipennis. Most of the earlier references to these two species in eastern Canada probably refer to earlez. The species is confined to Alaska, northern United States east of the Rocky Mountains, and Canada. In Canada, it has been recorded from Labrador to British Columbia. In Ontario earlei is the commonest species of the genus. It is nowhere abundant but is found locally over most of the province as the following locality records show: Algonquin Park, Biscotasing, Camp Borden, Cobourg, Guelph, Kingston, Lyn, Little Current River, Nagagami River, Kenora, Orillia, Peterborough, Trenton, Toronto, Welcome Lake, Westree, Grand Valley. BIOLOGICAL NOTES. Larvae are found in woodland pools, open bogs, round the margins of permanent and semi-permanent pools, and often in small roadside puddles. They occur in the Don Valley, Toronto from mid-June to early October. Beckel and Atwood (8) found larvae in Algonquin Park from early July to early August. Both these records in- dicate that water temperatures must not be cold. Females hibernate, often in buildings and houses, and have been taken flying in a house at Grand Valley in December. They may be on the wing as early as March 21 (18). Anopheles punctipennis (Say) FEMALE. Medium sized species; wing length about 4.0. to 4.5 mm. Proboscis black. Palps dark, as long as the proboscis. Seutum yellow, with broad median gray stripe. Scutellum covered with yellow hairs and long brown setae. Abdomen covered with dark hairs. Tarsi dark. Wing spotted ; costa with a pale spot on outer third of wing, near tip of subcosta. MALE. Terminalia similar to earlet, from which they can be dis- tinguished by the shape of the lobes of the ninth tergite (Fig. 24). LARVA. (Fig. 75). Inner clypeal hairs (2) simple (rarely branched), with basal tubercles close together, separated by less than the width of one tubercle. Postclypeal hairs (4) usually with an average of 3 or fewer branches. DISTRIBUTION. Found from southern Canada to Mexico, and rang- ing throughout the whole of the United States (rare in the Rocky Mountain region). In Canada present in British Columbia, Manitoba, New Bruns- wick, Nova Scotia, Ontario and Quebec. Ontario records show it to be generally distributed over the southern part of the province, but rare or absent in the north; it has been taken at Algonquin Park, Ancaster, Arkell, Belleville, Brampton, Cayuga, Guelph, Ingersoll, Jordon, Kingston, London, Madoc, Marden, Rockcliffe, Ottawa, Peterborough, St. Thomas, Spencer- ville, Stittsville, Stoney Creek, Toronto, Trenton and Winona. BIOLOGICAL NOTES. Larvae are found in a variety of habitats, from large pools to small rain puddles, and occasionally in rain barrels and tin cans. In the United States they have been found in springs and pools in streams. The species is an outdoors one, and seldom enters build- — ings in the summer. During the winter it hibernates in buildings, hollow trees, etc., from which it may emerge to enter living quarters. The females will bite any time, particularly in early evening. The species is a late breeding one, larvae being found from late June and early July to the end of August. Overwintered females are found flying in late May. Anopheles quadrimaculatus Say FEMALE. Medium sized species; wing length 4.0 to 5.0 mm. Proboscis dark. Palps dark, as long as proboscis. Scutum covered with yellow to 128 brown hairs, with no definite pattern. Scutellum with yellow hairs and long dark setae. Abdominal tergites dark brown to black, covered with yellow-brown hairs. Tarsi dark. Wing spotted. MALE. The external spine of the claspette is bluntly rounded at the apex (Fig. 26). One or more leaflets of the phallosome bear minute teeth near the base of the leaflet. LARVA. (Fig. 76). Inner clypeéal hairs (2) simple, without branching or feathering; basal tubercles separated by at least the width of one tubercle, usually wider. Postclypeal hairs (4) with average of 3 or fewer branches. DISTRIBUTION. Found throughout eastern and central United States, and extending from southern Canada to Mexico; it is commonest in the southeast States. In Canada records are limited to Ontario and Quebec. Its distribution in Ontario appears to be largely confined to southern Ontario, as the following records show: Algonquin Park, An- caster, Barriefield, Belleville, Brampton, Brighton, Cayuga, Cobourg, Colborne, Hamilton, Gananoque, Jordon, Kingston, London, Madoc, Ottawa, Peterborough, St. Thomas, St. Catharines, Simcoe, Toronto and Trenton, BIOLOGICAL NOTES. Larvae are found in large pools, permanent ponds, canals and the debris on the surface of lakes; their presence in small puddles and temporary pools has only been occasionally recorded. The species is rare in Ontario and few dates of emergence are available. The larval period is known to be brief, perhaps only 12 to 20 days in summer. Judd (19) found larvae at London as early as June 9 and as late as July 30. Adults have been taken from July to the end of September. Females bite chiefly at dawn and dusk, resting in shaded places during the daytime. They will feed on wild and domestic animals as well as man. Winter hibernation of adults is the rule. A. quadrimaculatus is the chief vector of malaria in the United States, and there is an extensive literature on the life history and habits of this species. Anopheles walkeri Theobald FEMALE. Medium sized species; wing length 4.0 to 4.5 mm. Proboscis dark. Palps as long as proboscis, with a narrow white ring at the apex of each segment. Scutum covered with short yellow-brown hairs in the centre, and long dark hairs laterally. Scutellum covered with yellow-brown hairs and long dark setae, Abdominal tergites dark, covered with yellow-brown hairs. Tarsi dark. MALE. (Fig. 27). Resembles quadrimaculatus, from which it can be distinguished by the shape of the lobes of the ninth tergite and the absence of teeth on the phallosome leaflets. LARVA. (Fig. 77). Inner clypeal hairs (2) with sparse and minute feathering near the tips. Postclypeal hairs (4) with an average of 3 or fewer branches. DISTRIBUTION. Like A. quadrimaculatus this species is found chiefly in eastern North America, but ranges west as far as Texas and Nebraska in the United States. In Canada it is found across the southern part of the country from Nova Scotia to British Columbia. The following Ontario records show it to be generally distributed over the south and central parts of the province: Algonquin Park, Carleton Place, Cayuga, Fox Lake, Hamilton, Jordon, Kingston, London, Maberly, Ottawa, Peter- borough, Pt. Pelee, St. Thomas, Smith’s Falls, Spencerville, Sudbury, Toronto and Trenton. 129 BIOLOGICAL NOTES. Larvae are liable to be present in any stand- ing water. Pools and marshes with grass and rushes growing round the edges and with duckweed on the surface are likely breeding grounds; larvae may be found in such habitats throughout the summer. Adults are readily attracted to light traps. They rest in shaded places during the day, but may enter houses at night to bite people. While there is no data from Canada, American evidence indicates that this species overwinters in the egg stage in the northern part of its range (1). Genus WYEOMYIA Theobald This genus is chiefly tropical. Our only species is Wyeomyta smithu (Coq.). It is characterized by its small size, the tuft of setae on the pronotum, and the unfringed squamae. Palps are short in both sexes. Spiracular bristles are present, upper mesepimeral bristles present, lower mesepimeral bristles absent. In the male, the dististyle is diagnostic. Wyeomyia smith (Coquillett) FEMALE. Proboscis dark scaled. Scutum with dark brown appressed scales. Postnotum with a tuft of bristles (Fig. 29). Pleura with silvery scales. Abdomen brown dorsally, silvery ventrally. Wing scales dark. Tarsus of middle leg with distal half of second and all of third and fourth segments white scaled on one side. Other tarsi dark. — MALE. Similar in aspect to the female. The lobed dististyle easily distinguishes the species from any other. Terminalia as in Fig. 28. LARVA. (Fig. 78). Head about as long as wide. Antenna small, less than half the length of the head; antennal hair single, inserted on outer fourth of antenna. Head hairs: Upper (5) and lower (6) single. Comb of eighth abdominal segment with a single row of 7 to 12 scales. Air tube index 4.0 to 5.0; no pecten, but scattered long hairs on tube. Anal segment with saddle extending about three-fifths down the sides. Only two gills present, BIOLOGICAL NOTES. Larvae are found only in the water contained in the leaves of the Pitcher Plant, Sarracenia purpurea, at all times of the year. They overwinter in the pitchers where they can resist prolonged freezing. Their growth rate is slow; they remain in the larva stage for two months or more even in the laboratory. All reliable observations are to the effect that the females do not bite humans, and they are rarely taken in the field. In Ontario the species is found all over the province wherever bogs and marshes permit the growth of its host plant. The latter is commonest in northern Ontario, but given the right conditions is ubiquitous and a list of records is unnecessary. Genus URANOTAENIA Lynch Arribalzaga Only one species of this genus has been found in Ontario, U. sapphirina (O.8S.). Both male and female can be identified by the median longitudinal stripe of irridescent blue scales on the scutum. Similar irri- descent scales are found on the basal part of the proboscis and on the wings. Palps very short in both sexes. Uranotaenita sapphirina (Osten Sacken) FEMALE, A small species; wing length 2.5 to 2.7 mm. One spiracular bristle present. MALE. Claspettes absent. Phallosome of two sclerotized plates (Fig. 30). Palps and proboscis similar to those of female. 130 LARVA. (Fig. 80). This is the only species of mosquito in our area in which the larval head is longer than wide. The comb of the eighth abdominal segment has 7 to 10 scales on the distal margin of a large sclerotized plate. Pecten of 12 to 15 teeth not reaching middle of air tube; air tube tuft multiple, inserted near end of pecten. Anal segment com- pletely ringed by saddle. | DISTRIBUTION. This species is found throughout eastern North America, in Mexico and the West Indies. Canadian records are restricted to Ontario and Quebec. In Ontario it has been taken at Ancaster, Kingston, London, Ottawa, St. Thomas, Toronto and Trenton, indicating a limited distribution along and near the lower Lakes. BIOLOGICAL NOTES. Larvae are found in permanent pools and ponds with emergent or floating vegetation, often associated with Anopheles quadrimaculatus, during summer and early autumn. There is little or no data on larvae in Canada however, and the adult records are mostly from light traps. More collecting is necessary before local dates of emergence, etc., can be given. The females overwinter in hibernation; they rarely if ever bite man. Specimens of any stage are scarce in Canadian collections. Genus CULISETA Felt Culiseta is a genus largely confined to the temperate regions. Our Species are large, usually with spotted wings, and are known to overwinter as adults. _ Of the four species described below, alaskaensis has not been reported from Ontario, but from its distribution records, it would seem highly likely that it is to be found in the northern parts of the province. The keys should permit reliable identification of our species. KEYS TO SPECIES FEMALES 1. Hind tarsi with pale rings on some segments .......000.000000.0 ee. 2 UMC ebasimeniiinelymdarlhe i NS eh ke ae” Ue 2. Hind tarsi with broad pale rings, that of segment two covering one quarter to one third of the segment. Cross veins with scales ................ oy ten i ih ee | alaskaensis (Ludlow) Hind tarsi with narrow pale rings at both ends of basal segments. INOMSEAIES ON \CROSS\ VEINS i oe morsitans (Theo.) 3. Costa of wing with mixed white and dark scales ........ imornata (Will.) Costa of wing entirely dark scaled ........................ impatiens (Walker) MALE TERMINALIA le basistyle with basal lobe only Cie eee z Basistyle with both basal and small apical lobe |... 3 2. Lobes of ninth tergite rounded with prominent short spines along HAMM OaNA HREM ey meu aya en Ne ee OU Pai Suk Oy Ase imornata (Will.) Lobes of ninth tergite slightly raised, with slender setae (Fig. 34) vidos he at dice NN CURR, a ik Ge Sant tae a eet mn a cn mE morsitans (Theo.) 3. Posterior margin of eighth tergite with a long row of 30 to 40 short SHOWS GLEN oe C23 TR ag Se aU ect ean HT re a empatiens (Walker) Posterior margin of eighth tergite with a group of only a few spines. CUED ee ote eee Ae Pe GIR ARO CI SIN SE aaa ea alaskaensis (Ludlow) LARVAE (FOURTH INSTAR) 1. Antenna as long as head, tuft on apical third; head hairs long; pecten consisting’ of scales only - (Hie 286). Oe ae oe eee morsitans Antenna shorter than head, tuft inserted near middle; head hairs short; pecten consisting of scales and long hairs =o)... 22 See 2 Upper head hairs (5) and lower head hairs (6) similarly branched CWI) (BS a i NNN es ek ae impatiens Upper head hairs (5) with more branches than lower head hairs (6) 3. Antenna prominently spined and pigmented, tuft inserted ae middle o( Fig. 390). oe ee ee PG ee alaskaensis Antenna not prominently spined or pigmented, tuft inserted near middie (Fisk SQ) one es Se inornata Culiseta alaskaensis (Ludlow) FEMALE. A large species; wing length 6.0 to 7.0 mm. Proboscis and palps dark, with numerous white scales intermixed. Scutum dark brown, with many white scales, especially around the margins. Scutellum with white scales and dark setae on the lobes. Spiracular bristles yellow. Ab- dominal tergites dark, with broad white basal bands. Tarsi dark, with first segment sprinkled with white scales; basal white bands on segments 1 to 4, widest on hind tarsi. MALE. Terminalia as in Fig. 31. LARVA. (Fig. 90). Antenna less than half as long as head; antennal tuft multiple, inserted near middle of antenna. Head hairs: Upper (5) 5- to 7-branched; lower (6) 3- to 4-branched, Comb of eighth abdominal segment with many scales in a patch. Air tube index 2.5 to 3.5. Pecten of numerous teeth on basal fifth of air tube, followed by a row of hairs ex- tending to near apex of air tube; tuft large, multiple, inserted within pecten near base of air tube. Anal segment completely ringed by saddle. Ventral brush large, with 2 to 5 precratal tufts. Gills as long or longer than the saddle. DISTRIBUTION. This species is circumboreal, being found in North- ern Europe, Siberia and Western North America. On the latter continent it is found from Alaska to Colorado and across northern Canada to Hud- son’s Bay. It has not been reported from Ontario, but is included here because it has been taken at Churchill, Man., as reported by Twinn (34) and Freeman (8), and at Great Whale River, Que., by Jenkins and Knight (16) and Freeman (8). This suggests the probability of the species being found in the northern regions of Ontario bordering Hudson’s Bay and James Bay. BIOLOGICAL NOTES: Larvae are found in late spring and summer in open pools, river beds and adjacent pools especially where heavy vegetation is found along the banks. Females overwinter in hibernation; they are reported to be annoying in both open and shaded areas. Culiseta impatiens (Walker) FEMALE. A large species; wing length 5.0 to 6.0 mm. Proboscis and palps dark. Scutum reddish-brown; two narrow median yellow lines, often indistinct. Scutellum with dark setae on lobes. Spiracular bristles yellow. Abdominal tergites brown with basal white bands. Tarsi dark. MALE. Terminalia as in Fig. 32. The long row of short spines on the eighth tergite is diagnostic. 132 LARVA. (Fig. 88). Antenna about as long as head; antennal tuft multiple, inserted near middle of antenna. Head hairs: Upper (5) and lower (6) both multiple. Comb of eighth abdominal segment with many scales in a patch. Air tube index 2.5 to 3.0. DISTRIBUTION. Known from the northern United States, Canada and Alaska. Essentially a northern species, it is found in Canada from the Yukon to Nova Scotia, usually in forested regions. Type locality, St. Martin’s Falls, Ontario. Ontario records are all from the central and northern part of the province and include Algonquin Park, St. Martin’s Falls, Moose Factory and White River. More collecting would add to our knowledge of its distribution. BIOLOGICAL NOTES. Larvae are found in snow pools, ponds and roadside puddles, They are not found before June, and later broods may then be met with until early autumn. The females overwinter, and are perhaps the first species to be seen in the north country, often being on the wing when snow is still on the ground in March and April. These lay eggs in rafts on the water surface, which, hatching in a few days produce the first crop of larvae. Adults may be found throughout the summer, but it is still uncertain whether there is more than one generation a year. Females bite readily at any time of the day. Culiseta tnornata (Williston) FEMALE. A large species; wing length 5.0 to 6.0 mm. Proboscis and palps dark. Scutum with golden-brown and yellow scales intermixed. Scutellum with dark setae on lobes. Spiracular bristles yellow. Abdominal age dark, each with a basal white band widening at the sides. Tarsi ark. MALE. Terminalia as in Fig. 38. LARVA. (Figs. 87, 89). Antenna nearly half as long as head; an- tennal tuft multiple, inserted near middle of antenna. Head hairs: Upper (5) with more branches than lower (6). Comb of eighth abdominal seg- ment with many scales in a patch. Air tube index 3.5, Pecten of about 14 to 18 teeth on basal fourth of air tube, closely followed by an even row of long hairs extending to near the apex of the air tube; tuft multiple, inserted within pecten near base of air tube. Anal segment completely ringed by saddle. Ventral brush large with 1 or 2 precratal tufts. Gills as long or longer than the saddle. DISTRIBUTION. Found throughout North America from Mexico to the Northwest Territories, and from the Atlantic to the Pacific. In Canada it ranges from Ontario to British Columbia and the Yukon. Records are surprisingly few from Ontario. Twinn (34) indicates the presence of the species in the province but gives no locality. Judd (19) reports larvae and pupae associated with Aedes stimulans and A. fitchi at London. A good source of larvae was found a few years ago at Aberfoyle, but due to local drainage it no longer exists. BIOLOGICAL NOTES. Larvae are found in pools, ponds, ditches, and sometimes small containers during the summer months. In California they occur in brackish coastal waters. Females hibernate during the winter, emerging in spring and early summer; they rarely bite man, pre- ferring to feed on wild and domestic mammals. Adults can readily be caught in light traps. This species can be reared continuously in the laboratory; McLintock (24) gives directions. 133 Culiseta morsitans (Theobald) FEMALE. Medium to large species; wing length 5.0 to 5.7 mm. Proboscis and palps dark. Scutum dark brown, with two median reddish- brown bare stripes and two shorter bare stripes on either side of the median stripes. Scutellum with dark setae on lobes, Spiracular bristles yellow. Abdominal tergites dark, with basal white bands. Tarsi dark, but with pale rings at both ends of basal segments. MALE. Terminalia as in Fig. 34. LARVA. (Figs. 85, 86). Antenna as long as the head, curved; an- tennal tuft large, multiple, inserted at outer fourth of antenna. Head hairs: Upper (5) 4- to 6-branched; lower (6) long, double. Comb of eighth abdominal segment with many scales in a patch. Air tube long and narrow, index 6.0 to 7.0. Pecten of a few teeth on basal fifth of air tube; tuft large, 4- to 5-branched, inserted within pecten near base of air tube. Anal seg- ment longer than wide, completely ringed by saddle. Ventral brush large, with 6 or 7 precratal tufts. Gills variable, usually longer than saddle. DISTRIBUTION. Found in the United States, southern Canada, and Europe. Canadian records show it to be present from Prince Edward Island and Quebec to British Columbia and the Yukon. Ontario records are not numerous, but its distribution throughout the province appears to be widespread as the following locality list shows: Algonquin Park, Moose Factory, St. Thomas, Toronto, White River. | BIOLOGICAL NOTES. Larvae are found in marshes, bogs and cold pools; in Algonquin Park they are common in heath and alder bogs where the water is brown and acid. In England and Denmark the species may overwinter in the larval stage, but there appear to be no records of this in North America. The females rarely if ever bite man, and probably feed on birds. NOTE: In addition to the species of Culiseta described above, there is in the National Collection at Ottawa a single female of C. minnesotae taken at Ottawa. This species, described by Barr in 1957, is similar to morsitans but little is known of its biology and range (1). Genus MANSONIA Blanchard Mosquitoes of this genus have attracted the interest of biologists because of their larval habit of attaching themselves to the stems or roots of aquatic plants, in this manner obtaining oxygen without coming to the surface. The genus itself is a minor one, with only three species reported from North America. Of these, the one described below is found in Ontario. Mansonia perturbans (Walker) FEMALE. A medium sized species; wing length 4.0 mm. Palps about one fifth as long as proboscis. Eighth abdominal segment bluntly rounded. Posterior pronotal bristles present. Spiracular and postspiracular bristles absent. , MALE Terminalia as in Fig. 35. The stout, dark, blunt rod with smaller spine alongside is diagnostic. 3 LARVA. (Fig. 81). The short attenuated air tube, modified for piercing, identifies the larva. ; . DISTRIBUTION. The species is found all over the United States and southern Canada, extending into Mexico. In Canada it is found from Nova Scotia to British Columbia. Ontario records are from Algonquin Park, 134 Cochrane, Dryden, Galt, Kenora, Kingston, London, Ottawa, St. Thomas, Toronto and Trenton. These indicate a range covering most of the south of the province and extending to the central portions. BIOLOGICAL NOTES. Eggs are laid on the surface of ponds and areas of water where emergent vegetation is abundant. After emerging the larvae attach themselves to the submerged stems and roots of aquatic plants and remain attached in this manner during development, even the pupae attaching themselves to the stems by means of modified respiratory trumpets. The species overwinters in the larval stage. Adults emerge in spring and early summer and are strong fliers. The females are persistent biters; they are easily attracted to light traps. Genus PSOROPHORA Robineau-Desvoidy Only two species of this typically southern genus are known from Ontario. Of these, one is a very large and the other quite a small species. In the adult, both spiracular and postspiracular bristles are present. The female cerci are long and pointed. In the male, basal and apical lobes of the basistyle are absent. In the larva, the anal segment is completely ringed by the saddle, which is pierced on the mid-ventral line by tufts of the ventral brush. KEYS TO SPECIES FEMALES 1. Scutum with narrow median golden yellow stripe. Proboscis yellow on distal half, dark at tip. Abdomen light yellow. Hind tarsi with basal white bands on all segments. Large species ............0....000..00000000 ciliata Scutum with mixed brown and yellow scales in no definite pattern. Proboscis entirely dark. Abdomen dark. Segments of hind tarsi with- out basal white bands, but segments 4 and 5 entirely white. Small SD CCN OS ss aes eG ed eee e e eP ferox MALE TERMINALIA 1. Phallosome with a pair of dorsal toothed ridges and two lateral pro- jections on apical half (Fig. 36). Dististyle with subapical tooth ........ ee ryan eee Ce et sie he ciliata Phallosome cylindrical or conical without teeth or lateral projections on apical half (Fig. 37). Dististyle broad, without subapical tooth ... 5 dcvomes ohece ou ghieee CT SGRo elle Suet AS SON SIS rel ai et 10 ase tear ania ci ferox LARVAE (FOURTH INSTAR) 1. Pecten teeth numerous, 18 or more. Air tube tuft a single hair, An- renma oniycone third as lone asshead oo. se, ciliata Pecten with 3 to 5 teeth. Air tube tuft minute, multiple. Antenna ROMOer ral Mead ig ee Rn Ye cc a ferox Psorophora ciliata (Fabricius) FEMALE. Probably our largest mosquito. Wing length 6.0 to 7.0 mm. Palps one third as long as proboscis, dark. Scutum with a light yellow median stripe. Scutellum with light brown setae on_ lobes. Abdominal tergites yellow to light brown. Tarsi with broad basal white bands. The hind legs have a shaggy appearance due to their covering of erect scales. MALE. Terminalia as in Fig. 36. The tooth on the dististyle and the claspette filament are diagnostic. 135 LARVA. (Figs. 82, 83). Head broader than long. Antenna about one third as long as head. Mouth brushes prehensile, hairs hooked at tips. Head hairs: Upper (5) short and branched distally; lower (6) single, branched distally; postantennal (7) single, branched distally. Comb of eighth ab- dominal segment with 12 to 16 scales in a single row. Air tube index 3.0 to 4.0. Pecten of numerous teeth on basal half; tuft a single hair inserted beyond pecten. Anal segment ringed by saddle. Ventral brush short, extending whole length of anal segment and piercing the saddle. Gills about 3 times as long as saddle. DISTRIBUTION, This species is known from Cuba, Central and South America, and from eastern and middlewestern United States. In Canada records so far exist only for Ontario and Quebec. Twinn (34) reports the species from Ontario, but gives no locality. The National Collection, Ottawa, has Ontario specimens from Normandale, Vineland Station and Roseland, and we have at Guelph a specimen from Sarnia. BIOLOGICAL NOTES. Eggs are said to be laid in small cracks in the soil and may not hatch until after a winter in the soil. The larvae develop rapidly — often in a week in warm weather — in rain pools and other small areas of temporary water. They are predacious, feeding on other mosquito larvae. In the northern part of their range, larvae may be found in such habitats from May to September. The females are never common and are said to prefer feeding on horses rather than humans. Psorophora ferox (Humboldt) FEMALE. Small to medium sized species; wing length 3.7 to 4.0 mm. Proboscis dark. Palps dark, short. Scutum with dark brown and golden yellow scales intermixed. Scutellum with dark brown setae on the lobes. Abdominal tergites dark with purple reflections; small triangular white patches at the sides. Hind tarsi with segments 4 and 5 white. 3 MALE. Terminalia as in Fig. 37. The broad dististyle, and the peculiar claspette and claspette filament are diagnostic. LARVA. (Fig. 84). Antenna much longer than head; antennal tuft multiple. Head hairs: Upper (5) and lower (6) both double; postantennal (7) multiple. Comb of eight abdominal segment with 6 to 8 scales in a row. Air tube index 4.0 Pecten with 3 to 5 widely spaced teeth on basal third of air tube; air tube tuft minute, multiple, inserted laterally beyond the middle of pecten. Anal segment ringed by saddle. Ventral brush ex- tending almost the entire length of anal segment, and piercing saddle. Gills longer than the saddle. DISTRIBUTION. Found in South and Central America, West Indies, Mexico, eastern and midwest United States and southern Canada. The only Canadian record appears to be that of Hearle (12), who reports the capture of a single specimen at Jordon, Ontario, on August 3, 1916. BIOLOGICAL NOTES, In the United States this species is reported as being found, in the larval stage, in shaded rain pools and other bodies of temporary water throughout the summer months. Development is rapid, but the number of generations is unknown. Females bite readily and will attack in the open on cloudy days. Genus AH DES Meigen This is the commonest mosquito genus in Canada and in fact in the northern temperate zones of both hemispheres. Over half of our species are referred to it. Species such as punctor, stimulans and vexans are common throughout much of the province and are persistent biters. 136 In nearly all species of the genus overwintering takes place in the egg stage and there is normally only one generation a year in our latitudes. Adults usually emerge in May and June; earliest in the extreme south — Windsor-Chatham-London area, and nearly a month later in the northern parts of the province. Late rains and flooding may produce broods of larvae in summer and autumn. In some cases (e.g., A. canadensis) it is uncertain whether such broods are from overwintering eggs that failed to hatch in the spring, or are a true second generation from eggs laid by females that emerged in the spring. The many species make identification difficult. In recent years work by Rempel (27, 28), Beckel (2), Vockeroth (36, 37, 38, 39) and others has done much to improve the situation, but it is still acute when one considers the blacklegged northern species. When dealing with adults, newly- emerged specimens are essential; little can be done with badly rubbed individuals taken in the field (see, however, Beckel [2]). The best plan is always to secure larvae and then rear adults from these, thus obtaining perfect specimens of both sexes which can be compared with larvae or larval skins. The following keys are based on the examination of Ontario and other Canadian specimens, and comparison with the description of authors, particularly those who have worked with Canadian collections. Reference to Table I will be found useful in checking the presence or absence of some of the more reliable key characters of Aedes larvae. ; A compound microscope will be of great value in the identification of certain species of Aedes, particularly when viewing tarsal claws of adults and comb scales and spiculated saddles of larvae. KEYS TO SPECIES FEMALES ip larsal scements with white bands or rings 2 Tarsal segments without white bands or rings .........................0.... 11 2. Tarsal segments with white bands or rings on basal half of segments TA ees re Sina aa eae Bee e meee ese nrce esses erersecrerer sere ese s rere s esses ere eres rere esses sees ereseert ee weer eeeereeesereseseesssersesserenorn 3. Basal white bands on tarsi narrow, less than one fifth as long as BES OMMETES. he he ee Ae ee VELANS Basal white bands broader, at least one third as long as segments on PANCRAS ee oa Ra 4. Large yellow species. Abdominal tergites covered with yellow scales a a ee ee eon a, flavescens Abdominal tergites dark-scaled, with basal white bands .................. 5. Tarsal claw with main tooth long, and abruptly bent (Fig. 51) .......... Ur eG A ee excrucians Tarsal claw smaller, with main tooth not abruptly bent .................... be Pcurim unitormily reddish-brown ....0.000 08 ae TIPArIUs SeuLuim With, dark Median SthIDC..2 a ae ee ee ee € 7. Palps dark; segments 3 and 4 with pale basal rings .................... fitchir Palps dark; segments 3 and 4 without pale basal rings ....... stimulans 8. Wings with light and dark scales on most of the veins .................... 9 Winesalmost entinely dark scaled 2) 41300. a al 10 9. Both light and dark scales about equally distributed on wing veins. PEESEUEC aves Tidy O! AD s20n wa Bee Oe au campestris 10. sae 12. 13. 1a 15. 16. lp: 18. 1 20. ia AS 22. 23. 24. Third longitudinal vein usually with more dark scales than veins 2 or A. Tarsal claw asin, Pig AG ee ey ee ey een dorsalis Wing with patch of white scales at base of costa ................ atropalpus Wing with base.of costa- dark scaled * = 3. 4 1 canadensis Scutum with a broad median longitudinal stripe, widening consider- ably: posteriorly (Figs, 10°20)" 9 eo es eo Z Scutum with or without a median stripe, but if present not very broad and ‘not, widening’ posteriorly 7h eo Scutum with a pair of broad submedian white or yellow stripes, separated by a brown stripe of about the same width (Fig. 21) ............ trivittatus Scutum without two broad submedian whitish stripes ........ an Scutum without any contrasting lines or stripes.’ 7. ae 14 Scutum with contrasting lines or stripes (but not whitish or yellow- WIPE)! 4 age Oh See RE Se Ee one, iP AN Toe Gate 16 Lower mesepimeral bristles present 0.0... 3.2 ee 15 Lower mesepimeral bristles absent ©9005)... ee cinereus Scutum with many long black or brownish setae, giving a hairy appearance to the thorax (Fig. 15). Lower mesepimeral bristles 3 TO: Bi eo a TS ia a eel Ds or i net impiger Scutum with normal setae, uniformly golden brown, occasionally with faint median lines (Fig. 16). Lower mesepimeral bristles 1 to 5 ........ Dab eg suet eta cel GE Rea a Sea ee La a a intrudens Lower mesepimeral. bristles present: 22...) ee Lower mesepimeral bristles absent .:.))....... 0.0... ee Vays Hypostigial scale patch of few to many white scales .................... 18 Hypostigial scale patch absent = 20 19 Sternopleuron with scales extending about half way to anterior angle. Lower mesepimeral bristles 1, to 8 22.2 6 eee implicatus Sternopleuron with scales extending to anterior angle. Lower mese- pimeral bristles 3/to 6 25.3 2 ei trichurus Wing usually with patch of white scales at base of costa ................ 21 Wing usually lacking patch of white scales at base of costa ............ ne scutum uniformly brown. or almostiso o...9-..03-- ae abserratus Scutum with moderately broad dark brown stripe, occasionally divided by a narrow yellow line ~045.3.%.0 ee punctor Setae of scutellum nearly all black, Postcoxal scale patch present ...... RO tr ence iis Nenia Oa Miwa aia tea mM ARMM Sra ccce plonips Setae of scutellum dark or bronze. Postcoxal scale patch absent........ er eee nen ea Mayr NN Martane ee ALS CE NOPE GS ak ela communis Abdominal tergites with narrow basal white bands extending across the segments and widening at the sides ...........00....00...ce. sticticus Abdominal tergites without white bands extending across the seg- ments, but with narrow triangular white patches at the sides ........ 24 Sides and margins of the scutum yellow. Scutellum with dark brown setae on ‘the lobes. ee es ee ON oe aurifer Sides and margins of scutum silvery-white. Scutellum with a patch of white setae on the middle lobe’... 2) 22013 Ss ae triseriatus Sternopleuron with about 12'to 20°setae 2 eee diantaeus Sternopleuron with 5 to 10 (not more) setae .......... pein ae 0: decticus MALE TERMINALIA Dististyle furcate near base, inserted well before apex of basistyle CHI o 4A) ci ee eae aarti et 2 a MD hc tan eee cinereus Dististyle not furcate, inserted at apex of basistyle ........................ 2 138 10. L bes 13. 14. 15. IG: Dense tuft of setae at apex of claspette. Claspette filament absent. Claw of dististyle subapical in position (Fig. 67) .................... vexans No tuft of setae at apex of claspette. Claspette filament present. Claw OWOsvishyie apical I). POSITION |e ae es io el a 3 Glaw or dististyle half as‘lone as dististyle.. 8 2. triseriatus Claw of dististyle not more than one third as long as dististyle ........ 4. EAsistvie without apical lobe:.(Fig. 39) 2 atropalpus Basishvie: with distines apical lobe Pah A ea ee ey, 5 Basistyle with dense brushlike tuft of long setae on ventral side MOEMOASC Or aiCal LOG ak uk ik ae I ee RON eer St Basistyle lacking dense brushlike tuft near base of apical lobe ........ if Apical lobe of basistyle elongate. Claspette stem with a sharp inner EMUONe mer euCsralt MIG): {5 ea) oh Le oo oe diantaeus Apical lobe of basistyle short and broadly rounded. Claspette with stem only moderately curved, lacking a sharp inner angle decticus Claspette filament short, and partly cone-shaped ................. trichurus Claspette filament longer, ligulate or bladelike ...........00...0000000... 8 Basal lobe of basistyle with setae but lacking an enlarged spine... 9 Basal lobe of basistyle with one or more distinctly enlarged spines 10 Apical lobe of basistyle with numerous short flattened setae. Claspette iocment Meulate, GADCrING 6.4) fis oe canadensis Apical lobe of basistyle with a slender hairlike or broadened seta. Claspette filament wide near base, narrowing to a recurved tip ........ i eae Waa eee EXCTUCIANS Basistyle with conspicuous dense tuft of setae near apex ................ 11 Basistyle without conspicuous dense tuft of setae near apex .......... 12 Claspette filament with a large median barb-like retrorse projection arising from the convex side. Basal lobe of basistyle with a single LoMCe ShOUE Spine AL, AWeKe 0 I ee ee a ae aurifer Claspette filament with a median angular expansion on convex side, not barb-like. Basal lobe of basistyle with two stout spines at apex audealaeee COVSal Spine ab DASE Cok eee mntrudens Basal lobe of basistyle with one or two stout spines in addition to the nomnar lone stout Gorsal Spine 2.2083 ea. dorsalis Basal lobe of basistyle with only one strong spine (often followed DEOGKESSIVely-DyY Weaker Splines) (ceo ae 13 Claspette filament with a spinelike retrorse projection or barb on convex side, forming an actite angle 2.0... trivittatus Claspette filament ligulate, roundly expanded, or with an angular expansion on the convex side forming an obtuse angle .................... it Filament of claspette ligulate, not expanded on convex side, not broader at middle than the distal end of the claspette stem ................ We ee ee Dre ate ee ne Byam ecitis campestris Filament of claspette roundly or angularly expanded on convex side, broader at middle than the distal end of the claspette stem ............ 15 Basal lobe of basistyle a large rugose area raised basally and flattened distally, extending beyond the middle of the basistyle .......... flavescens Basal lobe of basistyle triangular, conical or bluntly rounded, not reaching beyond basal two-fifths of basistyle ...............0....0.2.004: 16 Claspette filament with a sharp angle or notch near base of GHeNE LC ieee NA a Ce eS ee ee en Sc Claspette filament without a sharp angle or notch near base of CGOUICAN CIC Op eerie ese a ek ely estat abe ies 18 18/5 18. OE 20. “ele 22. 23. Apical lobe of basistyle covered with normal straight setae, Basal lobe subconical. Claspette filament less than twice as wide (at its widest point) as the apical diameter of the claspette stem .................... fitchu Apical lobe of basistyle covered with short broad recurved setae. Basal lobe large, quadrate. Claspette filament expanded so that at its widest it is about twice the apical diameter of the claspette stem ... sticticus Claspette filament with a sharp angular expansion in the form of an obtuse angle on the convex sidé . 0 3... eee Claspette filament roundly expanded or evenly curved on convex side Basal lobe of basistyle long, narrow and conical or wedge-shaped ...... ene ne eT Re enn yee a te OL ee AL impiger Basal lobe of basistyle short, conical or rounded ....................0...... 20 Basal lobe of basistyle with apical row of stout setae preceded by a long strong dorsal Spine’ 2.0 3 a ee, ee emplicatus Basal lobe of basistyle with large strong dorsal spine and short setae, but without apical row of stout setae =:3..5... 2 stimulans Apical lobe of basistyle with many straight setae on inner surface .... Le te aioe bee Gee We role Sane fac SOE era op RE te ai A Oa alin, een ee COMMUNIS, PLIONUPS Apical lobe of basistyle with many short broad curved setae on inner Surface 275. Se ee ae ee eG Ze. Claspette filament roundly expanded near base of convex side ............ we Ee a ce Sa AEA aah oe Oe CO I Oe rE ee Tiparius Claspette filament uniformly curved on convex side ...................... Basal lobe of basistyle large, with small dorsobasal protuberance .... BON EE LETS OO AEs aN a SEES ge te oe a cr OC OS cc a punctor Basal lobe of basistyle medium-sized, with a large dorsobasal pro- tuberancé: <) esa. oe Se ee ee oh oe ee ae abserratus LARVAE (FOURTH INSTAR) - Anal segment completely ringed by saddle ..............0000. ee 2 Anal segment not completely ringed by saddle ................00..00 4 Comb of eighth abdominal segment with 5 to 7 scales arranged in a curved row; dorsal brush of anal segment reduced to 2 long hairs on each side (Fig. SBD Raabe Mae at ee eg me eT abserratus Comb of eighth abdominal segment with more than 10 scales ........ 3 Comb of eighth abdominal segment with 10 to 19 scales in an irregular double or single row; air tube index 3.0 (Fig. 120) ................ punctor Comb of eighth abdominal segment with 17 to 26 scales in an irregular patch; air: tube index:2:0 to.2:5: (Pie. 134). ee trivittatus Pecten of air tube with 1 or more distal teeth detached .................... 5 Pecten of air tube with all teeth fairly evenly spaced ........... eee. 16 4 to 6 distal teeth of pecten detached; air tube with several pairs of dorsal: tutts. (his. 13.) s2 5 oe, ee trichurus Air tube without. dorsal«tutte: oo Se eee 6 Air tube tuft inserted within the pecten; air tube index less than 2.5 (Big OZ) ee a AE ts ae atest ele pe Mee, oe atropalpus Air tube tuft inserted distal to the pecten ....... eee 7 Antenna as long or longer than the head De ee 8 Antenna shorter than the: head 3 7.4..23.5 2.45 3.272 = eee 9 Antenna longer than the head, not strongly arched, 3 long setae at apex of antenna, antennal tuft inserted near middle of shaft; comb of eighth abdominal segment with less than 15 scales in an irregular 140 EO. it. 12. 13. 14. 15. 16. img 18. zo. 20. 21. OV OR Oe LO yy ct ee eed er ty MR a OR ere tele diantaeus Antenna as long as head, strongly arched, constricted at insertion of tuft; tuft beyond middle of shaft; comb of eighth abdominal segment with more than 15 scales in a patch (Fig. 93) .........00..0000..0...... aurifer Comb of eighth abdominal segment with scales in a patch 3 or more MEU SCLCC Dire eens mer Woe ok ee Yt Fe eee cutee PI eT er eet 10 Comb of eighth abdominal segment with scales in a single or irregular SURMPAUN dO a pr tis ee SE ANE epi gee edn gn e s 1Z Air tube slender, index 5.0, pecten with distal 1 to 3 teeth detached oP hee, LG ae Sala Se ae a oe ee ne ae a le excrucians Pere. ) 4- or more branched (rarely 3- branched), lower head hairs (6) 3- or more branched (Fig. 121) ............ plonips Upper head hairs (5) 1- to 3-branched, lower head hairs (6) 1- or P-aranchee (barely o-Dranched ): 0 ee ee eek 7A Air tube tuft inserted near distal 24 of air tube; anal gills short and bud-like, occasionally as long as saddle (Fig, 107) ............ dorsalis 141 Air tube tuft inserted near middle of air tube; anal gills as long or longer than the saddle «cei ee 22. Spicules towards apex of saddle on anal segment weakly developed, less than twice as long as those towards base of saddle and not longer than the diameter of the setal ring of the lateral hair (Fig. 101)... Pic tale Ged ee NG yr ba Cram gy 20ND) co Ms! Ng ingra 4) ea sy. COMMUTES Spicules towards apex of the saddle on anal segment well developed, more than twice as long as those towards the base of the saddle and usually longer than the diameter of the setal ring of the lateral hair Pee ee ee en Ree Ce Le 23. Upper head hairs (5) single or double, lower head hairs (6) single (rarely both head hairs double)’ (Mic. 118)... ee implicatus Upper head hairs (5) usually double (occasionally single or triple), lower head hairs (6) single (rarely both head hairs single) (Fig. 129) SP GSS ae BE Oe RU a es Ay i ates eed ne Sec cae stimulans 24. Upper head hairs (5) 2- to 4-branched, lower head hairs (6) double (sometimes single or triple) ; antennal tuft inserted near middle of shaft nearly reaching tip of shaft; comb of eighth abdominal segment with 18:to 25 scales in a patch: (lig, 1257127) 7 Ea Gees sticticus Upper head hairs (5) 4- to 9-branched, lower head hairs (6) 4- to 8-branched, postantennal hairs (7) 12-branched; antennal tuft multi- ple, inserted before middle of shaft, reaching near the tip of shaft; comb of eighth abdominal segment with less than 60 scales in a patch (F109 96) oe ak oe eg ee ea canadensis Aedes abserratus (Felt and Young) FEMALE. Medium sized species; wing length 4.0 to 4.7 mm. Proboscis and palps dark. Scutum uniformly golden-brown, usually no median stripe. Scutellum with light brown setae on the lobes. Hypostigial scale patch absent. Lower mesepimeral bristles 1 to 3. Postcoxal scale patch present. First tergite of abdomen with median patch of pale scales; remaining tergites dark scaled, each with a basal white band. Tarsi dark. MALE. Terminalia as in Fig. 38. The basal lobe of the basistyle is subtriangular in shape, and has a small conical protuberance at its distal end; proximally it is indented, so that the lobe appears to be attached to the basistyle by a wide neck. LARVA. (Fig. 91). Antenna about half as long as the head; antennal tuft multiple, inserted just before middle of antenna. Head hairs: Upper (5) single (occasionally double); lower (6) single; postantennal (7) 2- to 4-branched. Comb of eighth abdominal segment with 5 to 7 scales in a curved row. Air tube index 3.0 to 3.5. Pecten with 11 to 20 teeth, not reaching the middle of the tube, the distal 2 or 3 teeth often weakly detached; air tube tuft 2- to 4-branched, inserted beyond pecten. Anal segment completely ringed by saddle. Dorsal brush with 2 single hairs on each side, Ventral brush confined to barred area, no precratal tufts. Gills 114 to 214 times as long as the saddle. 3 DISTRIBUTION. As far as present records go, this species is limited to the northeastern United States and southeastern Canada. In Canada it is recorded from Labrador, Nova Scotia, Ontario and Prince Edward Island. Ontario records are from Algonquin Park and Moose Factory. Earlier records of the species are usually under the name implacabilis (39). The species is rare and in the past has been confused with punctor and hexodontus (1, 39). 142 ~ BIOLOGICAL NOTES. Larvae are found in woodland pools, ditches, heath and alder bogs in April and May, and are present until late June. Females are said not to be persistent biters, but at present there is a dearth of information on the life history and habits of the species. Aedes atropalpus (Coquillett) FEMALE. Small to medium species; wing length 3.0 to 3.5 mm. Proboscis and palps dark. Scutum with a broad dark brown longitudinal band, somewhat wider posteriorly. Scutellum with dark setae on lobes. Hypostigial scale patch absent. Lower mesepimeral bristles absent. Post- coxal scale patch absent. First abdominal tergite dark with a few scattered white scales; remaining tergites dark each with narrow basal white bands, widening at the side. Hind tarsi with both basal and apical bands on segments 1 to 4, segment 5 nearly all white; front and middle tarsi with white bands, at least on segments 1 and 2. MALE. Terminalia as in Fig. 39. The absence of spines or setae on the lobes of the ninth tergite, and the seta on the claspette are useful spots. LARVA. (Fig. 92). Antenna barely half as long as head; antennal tuft small, double or triple, inserted near middle of antenna. Head hairs: Upper (5) and lower (6) single; postantennal (7) 2- to 5-branched. Comb of eighth abdominal segment with variable (20° to 50) scales in a patch. Air tube short, stout, index 1.5 to 2.0. Pecten of 14 to 20 teeth, extending nearly to end of air tube, the last few teeth detached; tuft 4- to 9-branched, inserted within the pecten. Anal segment with saddle extending less than half way down the sides, Ventral brush large, insertion confined to barred area, no precratal tufts. Gills usually long, 3 to 4 times as long as saddle. DISTRIBUTION. Known from Central America, much of the United States and scutheast Canada. Generally considered an uncommon species, but often abundant locally. Canadian records are from Labrador, Ontario and Quebec. The only Ontario record is that of Twinn (34) who however gives no locality. BIOLOGICAL NOTES. Larvae are found in rock holes and small pools along rivers and streams, particularly when the latter are subsiding after spring floods. They do not appear before June, and may be found until September if rain or spray prevent the holes from drying up. In the southern United States the larvae have been found in tree holes. In Quebec they are found associated with Culex territans and occasionally with Aedes punctor. Females are reported as being persistent biters, but are seldom found far from larval habitats. Aedes aurifer (Coquillett) FEMALE. Medium sized species; wing length 3.7 to 4.0 mm. Pro- boscis and palps dark. Scutum with a broad medium purplish-black stripe, widening posteriorly (Fig. 10); sides and prescutellar space yellow. Scutellum with dark brown setae on the lobes. Hypostigial scale patch absent. Lower mesepimeral bristles absent. Postcoxal scale patch absent. First tergite of abdomen dark with a few white scales; remaining tergites dark with small lateral triangular white patches. Tarsi dark. MALE. Terminalia as in Fig. 40. The claspette filament, with its Sharp retrorse projection, and the stout spine on the basal lobe of the basistyle, are useful points. | LARVA. (Figs. 93, 94). Antenna as long as head, curved; antennal tuft large, multiple, inserted beyond middle of antenna. Head hairs: Upper (5) double or triple; lower (6) double; postantennal (7) multiple. Comb 143 of eighth abdominal segment with 20 to 30 scales in an irregular triple row or patch. Air tube index 3.5 to 4.0 Pecten with 12 to 20 teeth not quite reaching middle of tube, with distal 1 to 2 teeth detached; tuft multiple, inserted beyond the pecten, Anal segment with saddle nearly encircling the segment; saddle pointed at posterior end. Ventral brush large, with 3 or 4 small precratal tufts. Gills about as long as the saddle. DISTRIBUTION. Found in northeastern and north central United States and southern Canada. Canadian records are from Manitoba, Ontario and Quebec. In Ontario known from Carlton Place, Galt, Marmora and the Ottawa region. BIOLOGICAL NOTES. Larvae are found in roadside and woodland pools, but more often in bogs and marshes, from April to midsummer. Females bite freely during the daytime and in the evening. Generally considered an uncommon species, but sometimes abundant locally (e.g., the Galt bog, Galt). Aedes campestris Dyar and Knab FEMALE. Medium to large species; wing length 4.4 to 5.0 mm. ~ Proboscis black, with pale scales on basal half. Palps black, with a few white scales, Scutum light yellow, with a broad median brown stripe (Fig. 11). Scutellum with golden setae on the lobes. Hypostigial scale — patch present. Lower mesepimeral bristles 2 to 7. Anterior abdominal tergites predominantly white, with black lateral patches on anterior seg- ments, diminishing in size posteriorad. Hind tarsi with both basal and apical white bands on segments 2 to 4; segment 5 usually all white. Middle tarsi with basal and apical bands on segments 2 and 3, and a basal band on segment 4. Front tarsi with only basal bands on segments 2 and 3. Specimens are difficult to distinguish from those of A. dorsalis; the tarsal claw is a useful point (Fig. 42). MALE. Terminalia as in Fig. 41. The claspette filament is ligulate, or sickle-shaped, differing in this point from the broader filament of dorsalis. LARVA. (Fig. 95), Antenna shorter than the head; antennal tuft multiple, inserted near middle of antenna. Head hairs: Upper (5) double or triple; lower (6) single (occasionally double) ; postantennal (7) 6- to 10-branched. Comb of eighth abdominal segment with 20 to 30 scales in an irregular patch. Air tube index 3.0. Pecten with 20 to 30 teeth, extending just beyond middle of air tube, the distal:1 or 2 usually detached; air tube tuft 4- to 6-branched, inserted beyond pecten. Anal segment with saddle extending two-thirds down the sides. Ventral brush large with 3 or 4 precratal tufts. Gills small and bud-like, much shorter than the saddle. DISTRIBUTION. Typically a species of the western plains of North America (type locality Oxbow, Sask.) but extends northwards to Alaska | and the Yukon. In Canada it is one of the commonest species on the prairies, but is rare in the east. It has been found in British Columbia, Manitoba, Ontario, Quebec, Saskatchewan and the Yukon. The few Ontario records are from Charlton Island, Moose Factory and Moosonee, indicating a northern distribution. BIOLOGICAL NOTES. Larvae are found in pools and waterfilled depressions where the water is alkaline and often with a rich organic con- tent. At Churchill, Manitoba, larvae were found at the end of June, and the adults were on the wing in July (14). Rempel (28) gives late May and early June for adults in Saskatchewan, and states that a second brood may appear in late August if conditions are favourable. The females rest in the grass during the daytime and bite readily when disturbed. 144 Aedes canadensis (Theobald) FEMALE. Small to medium species; wing length 3.3 to 4.3 mm. Proboscis dark. Palps short, with white scales at tip. Scutum golden-brown, nearly uniformly coloured but paler on anterior and lateral margins and on the prescutellar space (Fig. 12). Scutellum with dark brown setae on the lobes. Hypostigial scale patch absent. Lower mesepimeral bristles absent. Postcoxal scale patch absent. Abdominal tergites dark, with nar- row basal white bands. Tarsal segments with basal and apical white bands on all segments, broadest on hind tarsi where segment 5 is entirely white. MALE. Terminalia as in Fig. 43. The basal lobe of the basistyle, which is broadly conical and covered with short setae each arising from -a small tubercle, is characteristic. LARVA. (Figs. 96, 97, 98). Antenna about half as long as head; antennal tuft multiple, inserted before middle of antenna. Head hairs: Upper (5) 5- to 8-branched; lower (6) 3- to 5-branched; postantennal (7) 8- to 12-branched. Comb of eighth abdominal segment with 20 to 35 or more scales in an irregular triangular patch. Air tube index 3.0 to 3.5. Pecten with 13 to 20 evenly spaced teeth on basal two-fifths of air tube; tuft 4- to 6-branched, inserted beyond pecten. Anal segment with saddle extending about two-thirds down the sides. Ventral brush large, with 1 or 2 precratal tufts. Gills 1 to 114 times as long as saddle. DISTRIBUTION. Widely distributed over all of North America where forested regions occur. Recorded from nearly all states in the United States and in all Canadian provinces and the Yukon. Type locality De Grassi Point, Lake Simcoe, Ontario, Found almost everywhere in Ontario, as the following records indicate: Aberfoyle, Algonquin Park, Camp Borden, Dryden, Elora, Galt, Guelph, Jordon, Kenora, Moose Factory, Moosonee, Orillia, Ottawa, London and White River. BIOLOGICAL NOTES. Larvae may be encountered in any standing water, large or small, in or near woods, and often in bogs and swamps in forest regions. It is an early species; larvae may be found in early April in southern Ontario, and adults in early May; in Algonquin Park _ larvae are found in May, adults in July. Larvae are often found in August and September, but whether this is a true second generation or a later brood from previously unhatched eggs flooded by late summer rains is uncertain. Adults are found throughout the summer and the females are ready biters. | Aedes cinereus Meigen FEMALE. Small to medium species; wing length 3.2 to 3.8 mm. Pro- boscis and palps dark. Scutum uniformly red-brown, paler around margins and prescutellar area. Scutellum with brown setae on lobes. Hypostigial scale patch absent. Lower mesepimeral bristles absent. Postcoxal scale patch absent. Abdominal tergites dark brown to black, without white bands. Tarsi dark. MALE, Terminalia as in Fig. 44. The subapical insertion of the disti- _ Style is diagnostic. The palps are quite short — as short or shorter than those of the female. LARVA. (Fig. 99). Antenna more than half as long as head; antennal tuft multiple, inserted near middle of antenna. Head hairs: Upper (5) 5- to 8-branched; lower (6) 4- to 6-branched; postantennal (7) multiple. Comb of eighth abdominal segment with 9 to 16 scales in an irregular double row. Air tube index 4.0 to 4.5. Pecten with 15 to 20 teeth, with distal 1 to 3 teeth detached; tuft small, 3- to 5-branched, inserted beyond 145 pecten. Anal segment with saddle extending about three-quarters down the sides. Ventral brush well developed, with 3 to 4 precratal tufts. Gills with dorsal pair about 214 times as long as the saddle; ventral pair a little shorter than the dorsal pair. DISTRIBUTION. Known from Asia, Europe, and most of North America. In the United States it is typically a northern species, being — uncommon in the south. In Canada it is recorded from all provinces and territories, In Ontario it has been collected at Algonquin Park, Coral Rapids, Dryden, Galt, Guelph, Kenora, Moose Factory, Moosonee, Ottawa, Waterloo and White River. Such a distribution indicates a general occur- rence throughout the province. } BIOLOGICAL NOTES. Larvae are found in woodland pools, rain pools and often in marshes and bogs, appearing in April in the south and about a month later in the north of the province. Adults are common in July, but as a rule the species is not abundant anywhere. The females are troublesome biters. Aedes communis (De Geer) FEMALE. Medium to large species; wing length 4.5 to 5.0 mm. Pro- boscis and palps dark. Scutum with golden-yellow and brown scales, the pattern variable; usually there are two submedian brown stripes separated by a narrow yellow band (Fig, 13). Scutellum with dark setae on the lobes. Hypostigial scale patch absent. Lower mesepimeral bristles 2 to 6. Postcoxal scale patch absent, Abdominal tergites dark, with white basal bands narrower in the middle. Tarsi dark. Communis is notoriously variable, and often difficult to separate from other black-legged species like intrudens. The absence of the postcoxal scale patch distinguishes it from pionips and implicatus. Hocking et al (14) have shown by statistical consideration of measurements that the Species can be separated into two groups; the smaller of these lays eggs without a blood meal. Vockeroth (39) and Beckel (2) report that communis at Churchill does not bite. Barr (1) in Minnesota reports the Species as a vigorous biter, as do most workers in other parts of North America and Europe. It is possible that these authors may have studied the two differing groups of Hocking. MALE. Terminalia as in Fig. 45. Resembles implicatus, from which it can be separated by the shape of the claspette filament (and also the postcoxal scale patch). But communis is difficult to distinguish from pionips, and there are no reliable differences in the terminalia. However, in male pionips, the palps are shorter than the proboscis, and the apical palp segment is not enlarged; in communis the palps are longer than the proboscis and the last segment of each is enlarged at the apex. LARVA. (Figs. 101, 102, 103). Antenna shorter than the head; antennal tuft multiple, inserted before middle of antenna. Head hairs: Upper (5) and lower (6) single (occasionally double) ; postantennal (7) 5- to 8-branched. Comb of eighth abdominal segment with many (around 60) scales roughly in a triangular patch, Air tube index 2.5 to 3.0. Pecten with 15 to 20 evenly spaced teeth not reaching the middle of the air tube; tuft 5- to 9-branched, inserted beyond pecten. Anal segment with saddle extending about two-thirds down the sides. Saddle weakly spiculated. Ventral brush large, with 2 to 4 precratal tufts. Gills 2 to 214 times as long as saddle. . DISTRIBUTION. One of the most widely distributed species of mosquitoes in the northern hemisphere, being known from Siberia, north- ern Europe, northern United States, Canada and Alaska. In Canada it 146 is found in every province and territory. In Ontario records show it to be general and often abundant throughout the province. The following partial list of localities where it has been taken could easily be doubled: Aberfoyle, Algonquin Park, Camp Borden, Dryden, Eramosa, Port Hope, Height of Land, Moose Factory, Nipigon, Kenora, Osnaburg, Ottawa, Toronto and White River. BIOLOGICAL NOTES. Larvae may be found in almost any small body of standing water in early spring. In southern Ontario adults may be on the wing by the middle of May and by late May in central Ontario (Algonquin Park). Large swarms of this species are often encountered and testify to its abundance. Aedes decticus Howard, Dyar and Knab FEMALE. Small to medium species; wing length 3.0 to 3.5 mm. Proboscis and palps dark. Scutum yellow, with two medium dark brown stripes, sometimes fused into a single broad stripe. Scutellum with light brown setae on the lobes. Hypostigial scale patch absent. Lower mesepi- meral bristles absent. Abdominal tergites purplish-brown with small tri- angular white patches at the sides. Tarsi dark. MALE. Terminalia as in Fig. 46. The small tuft of setae near the apex of the basistyle, and the sharp right-angle bend of the claspette stem are diagnostic. LARVA. (Fig. 104). Antenna about three-quarters as long as head; antennal tuft usually double, inserted near middle of antenna. Head hairs: Upper (5) and lower (6) single or double; postantennal (7) usually double (occasionally 3- or 4-branched). Comb of eighth abdominal segment with 5 to 7 scales in a curved row. Air tube index 3.5 to 4.0, Pecten with 10 to 15 teeth, reaching just beyond middle of air tube; tuft 3- to 7-branched, inserted beyond pecten. Anal segment with saddle nearly encircling the segment, but not completely fused. Ventral brush moderately developed, with 1 to 3 precratal tufts. Gills 114 to 214 times as long as the saddle. DISTRIBUTION. Known only from a limited area in northeastern United States, southeast Canada and Alaska. In Canada it has been found in Labrador and Ontario (type locality White River, Ont.). The only other record in Ontario is from Algonquin Park. BIOLOGICAL NOTES. Little is known about this species, which is uncommon or rare throughout its range. In the United States larvae have been found in woodland pools, swamps, and sphagnum bogs, associated with A. canadensis, A. abserratus, A. cinereus and Culiseta morsitans. Its bite is said to be scarcely noticeable. Aedes diantaeus Howard, Dyar and Knab FEMALE. Medium sized species; wing length 4.0 to 4.5 mm. Pro- boscis and palps dark. Scutum golden yellow with two median brown stripes, sometimes fused into one broad stripe; the stripes terminate usually before reaching the prescutellar area. Scutellum with light brown setae on the lobes. Hypostigial scale patch absent. Abdominal tergites purplish-brown, without white bands, but with small white spots or tri- angles at the sides. MALE. Terminalia as in Fig. 47. The large tuft of setae on the medial surface of the basistyle is diagnostic. LARVA. (Figs. 105, 106). Antenna as long or slightly longer than the head, nearly straight; antennal tuft 3- to 7-branched, inserted near middle of antenna. Head hairs: Upper (5) usually triple; lower (6) double or 147 triple; postantennal (7) 3- to 6-branched. Comb of eighth abdominal seg- ment with 6 to 12 scales in an irregular double row, Air tube index 3.5 to 4.0. Pecten with 138 to 20 teeth, all on basal half of tube, with 1 to 3 teeth detached; tuft 4- to 8-branched, inserted beyond the pecten. Anal segment with saddle extending three-quarters or more down the sides. Ventral brush well developed with 3 or 4 precratal tufts. Gills about twice as long as saddle. DISTRIBUTION. Typically a species of the forest regions of the northern hemisphere, being found in Siberia, northern Europe and north- ern North America. In Canada it is found across the country from Nova Scotia to British Columbia. Ontario records include specimens from Algonquin Park, Cochrane, Coral Rapids, Eramosa, Moose Factory, Moosonee, Toronto and White River. BIOLOGICAL NOTES. Larvae are found in shaded snow pools in woods and forests, usually associated with other species of mosquitoes. Larvae are late appearing, seldom being found before May, and remaining until July. Data are meagre about this species, which while it has a wide range in the country, is uncommon anywhere. Aedes dorsalis (Meigen) FEMALE. Medium sized species; wing length 4.0 to 4.5 mm. Pro- boscis and palps dark, with sprinklings of pale scales, Scutum (Fig. 14) yellow with a broad stripe of brown scales, not reaching prescutellar area, often projecting posteriorly as three narrow stripes. Scutellum with light brown setae on lobes. Hypostigial scale patch present. Lower mesepimeral bristles 2 to 6. Abdominal tergites white, with medio-lateral black patches. Hind tarsi with segments 1 to 3 with basal and apical white bands; seg- ment 4 with basal white band only; segment 5 white. Middle tarsus with narrow basal and distal bands on segments 1 to 3. Front tarsi with basal and distal bands on segments 1 and 2. Tarsal claw as in Fig. 49. MALE Terminalia as in Fig. 48. Compared with canadensis the claspette filament is broader and there is no dense patch of setae on the apical lobe of the basistyle. LARVA. (Figs. 107, 108). Antenna half as long as head; ae tuft multiple, inserted near middle of antenna. Head hairs: Upper (5) single (occasionally double); lower (6) single (rarely double) ; post- antennal (7) multiple. Comb of eighth abdominal segment with 18 to 28 scales in a patch, Air tube index 2.5 to 3.0. Pecten of 16 to 23 teeth, reach- ing middle of air tube; tuft 4- to 7-branched, inserted beyond pecten. Anal segment with saddle extending nearly two-thirds down the sides. Ventral brush large, with 2 to 5 precratal tufts. Gills variable; may be quite short if from brackish water. DISTRIBUTION. This is a northern species, known from Europe, Asia and North America. In Canada it is found from Quebec to British Columbia. It is a rare species in Ontario, having been taken only at Moose Factory and Moosonee. BIOLOGICAL NOTES. Larvae prefer alkaline water, and unlike most Aedes species, are tolerant to sunshine and exposed situations. In Utah they have been found along the margins of the Great Salt Lake, where the salinity of the water is 12%. Common on the prairies, the larvae are often abundant in shallow weedy pools where the water is alkaline and rich in organic matter (28). The larvae are said to appear in early Summer in Saskatchewan, and adults are on the wing in late July and in August. A second brood may appear in September. ns females are vicious biters. 148 Aedes excrucians (Walker) FEMALE. A large species; wing length 5.0 mm. Proboscis with mixed brown and white scales. Palps dark, with white scales at apices of segments. Scutum golden brown with variable white patches or stripes. Scutellum with brown setae on the lobes. No hypostigial scale patch. Lower mesepimeral bristles absent (rarely 1). Postcoxal scale patch present. Abdominal tergites dark, with irregular basal white bands; posterior tergites nearly all white. Hind tarsi with broad white basal bands on all segments. Middle and front tarsi with narrower white bands on proximal segments. The claw (Fig. 51) is distinctive. MALE. Terminalia as in Fig. 50. The basal lobe is a flat rugose area with many small setae arising from tubercles. The claspette filament is subtriangular, with a recurved tip. LARVA. (Fig. 109). Antenna shorter than the head; antennal tuft 3- to 5-branched, inserted before middle of antenna. Head hairs: Upper (5) and lower (6) double; postantennal (7) 5- to 7-branched. Comb of eighth abdominal segment with 20 to 30 scales in an irregular or triangular patch. Air tube slender, index 5.0. Pecten of 16 to 25 teeth not reaching middle of tube, with distal 1 or 2 teeth detached; tuft 4- or 5-branched, inserted beyond pecten. Anal segment with saddle extending three- quarters down the sides. Ventral brush large, with 3 to 5 precratal tufts. Gills from 1 to 2 times as long as saddle. DISTRIBUTION. Found in the northern forests of Asia, Kurope and North America (type locality, Nova Scotia). In Canada it has been re- corded from all provinces and territories. Found throughout the whole of Ontario as evidenced by the following records: Algonquin Park, Galt, Guelph, Dryden, London, Moose Factory, Moosonee, Orillia, Ottawa, To- ronto, Trenton, White River. BIOLOGICAL NOTES. Larvae are found in woodland pools, and a variety of other habitats — swamps, bogs and grassy marshes. Present in the south of the province:from mid-April to mid-June or later. In Algonquin Park these dates are about a month later. Females are most active in the evening but will bite during the day in the woods; they may be encountered until late September. A common species over most of its range. Aedes fitchi (Felt and Young) FEMALE. Medium to large species; wing length 4.5 to 5.0 mm. Proboscis dark with scattered white scales. Palps dark with white rings at bases of segments 3 and 4. Scutum yellow with a broad median dark brown stripe. Scutellum with brown setae on the lobes. Hypostigial scale patch absent. Lower mesepimeral bristles variable, usually 0 to 2. Post- - coxal scale patch present. Abdominal tergites dark brown with central white bands not reaching the sides. Hind tarsi with broad white bands on all segments. Middle and front tarsi with narrower basal white bands. The mesonotal pattern resembles that of stimulans, and the two species are difficult to separate. MALE. Terminalia as in Fig. 52. The shape of the basal lobe and the rather narrow claspette filament are useful features. LARVA. (Figs. 111, 112). Antenna half as long as head; antennal tuft multiple, inserted near middle of antenna. Head hairs: Upper (5) 3- to 4-branched; lower (6) double or triple; postantennal (7) multiple. Comb of eighth abdominal segment with variable (10 to 36) number of scales (see Barr, 1) in a patch. Air tube index nearly 5.0. Pecten with 18 to 24 teeth nearly reaching middle of tube; tuft 4- to 5- branched, 149 inserted beyond pecten. Anal segment with saddle extending two-thirds down the sides. Ventral brush large, with 1 or 2 precratal tufts. Gills 114 to 214 times as long as saddle. DISTRIBUTION. A species confined to the forests of North America. Found in Canada from Labrador to Alberta. Not common in Ontario, but the following records show it to be present over most of the province: Algonquin Park, Campbellville, Camp Borden, Dryden, Elora, Guelph, London, Moose Factory, Orillia, Rockwood, Toronto, White River. BIOLOGICAL NOTES. Larvae are found in temporary and semi- permanent grassy pools, often in deeper water than most species. May be present about the beginning of May in the south, and mid-May in the north. Adults are on the wing in late June and may be taken biting in August. They are said to attack cattle and other mammals as well as man. Aedes flavescens (Miller) FEMALE, A large characteristically yellow species; wing length 5.5 to 6.0 mm. Proboscis and palps dark brown, each with scattered yellow scales. Scutum golden yellow, with a broad median stripe of brown scales. Scutellum with brown setae on the lobes. Hypostigial scale patch present. Lower mesepimeral bristles absent. Abdominal tergites entirely yellow, except for a few small submedian dark spots. Hind and middle tarsi with broad basal yellow bands on segments 2 to 5. Front tarsi with basal bands on segments 2 to 4. Wing scales yellow, with a few brown scales. The large size and predominantly yellow aspect of this species distinguish it from others of the genus. The tarsal claw is also a good point (Fig. 54). MALE. Terminalia as in Fig. 53. LARVA. (Fig. 110). Antenna about half as long as head; antennal tuft multiple, inserted near middle of antenna, Head hairs: Upper (5) 3- to 4-branched; lower (6) double or triple; postantennal (7) multiple. Comb. of eighth abdominal segment with 20 to 386 scales in’ a patch. Air tube index 3.5 to 4.0. Pecten with 18 to 26 teeth on basal two- fifths of tube, often with 1 or 2 distal teeth detached; tuft 4- or 5-branched, inserted beyond pecten. Anal segment with saddle extending three-quarters down the sides. Ventral brush large with several precratal tufts extending to base of segment. Gills 1 to 214 times as long as saddle. The larvae are variable, and for this reason often difficult to identify. DISTRIBUTION. Known from Asia, Europe and North America. In Canada found from Ontario to British Columbia; it is one of the commonest species in the prairie provinces. In Ontario it is uncommon, our only records being from Albany, Dryden, Kenora, Nipigon and White River. BIOLOGICAL NOTES. Larvae are found in semi-permanent water, meadow pools and marshes being typical breeding places. They are present in May. Adults may appear in June in Saskatchewan, disappear in July and reappear as a small second brood in August (28). Females bite readily when encountered, attacking both men and cattle. Aedes impiger (Walker) FEMALE. Small to medium species; wing length 3.3 to 4.2 mm. Proboscis and palps dark. Scutum covered with bronze-coloured scales, yellowish along margins, The scutum also bears many black setae (Fig. 15) giving the insect a hairy appearance. Scutellum with black setae on the lobes. Hypostigial scale patch absent. Lower mesepimeral bristles 3 to 8. Postcoxal scale patch present. Abdominal tergites black, with basal white bands. Tarsi dark. 150 MALE. Terminalia as in Fig. 55. The claspette filament is long, curved at tip, angularly expanded near the base. LARVA. (Figs. 113, 114, 115). Antenna half as long as head; an- tennal tuft small, usually triple, inserted before middle of antenna. Head hairs: Upper (5) and lower (6) single; postantennal (7) 2- to 4-branched Comb of eighth abdominal segment with 8 to 16 scales in a double irregular row. Air tube index 3.0. Pecten with 11 to 18 teeth on basal third of tube; tuft multiple, inserted beyond pecten, near middle of air tube. Anal seg- ment with saddle extending halfway down the sides. Ventral brush large, with 1 or 2 precratal tufts. Gills variable, from 2 to 4 times as long as saddle. DISTRIBUTION. A species of the far north, known from arctic regions of Siberia, Northern Europe and North America. In the United States it is found in Alaska and south through the Rocky Mountains to Colorado. Canadian records are chiefly from the north and far north. In Ontario it has been taken only at Moose Factory, and at St. Martin’s Falls, on the Albany River (the type locality), both far south of its normal range. BIOLOGICAL NOTES. Larvae are found in snow pools in the treeless regions of the arctic. The adult is one of the commonest and worst mosquitoes of the far north, but cannot normally be considered an On- tario species. Aedes wmplicatus Vockeroth FEMALE. A small to medium species; wing length 3.5 to 4.5 mm. Proboscis and palps dark. Scutum coppery-brown with a broad dark brown stripe or pair of stripes; anterior and lateral margins and prescutellar area with grayish-white scales. Scutellum with brown setae on lobes. Hypostigial scale patch present or absent. Lower mesepimeral bristles 1 to 3. Postcoxal scale patch present. Abdominal tergites brown with basal white bands. Tarsi dark. This is the impiger of many previous authors (Vockeroth, 38). White “‘knee spots’ present. MALE. Terminalia as in Fig. 56. The claspette filament is shorter than that of impiger. LARVA, (Figs. 116, 117, 118). Antenna half as long as head, or slightly less; antennal tuft multiple, inserted before middle of antenna. Head hairs: Upper (5) single or double; lower (6) single; postantennal (7) multiple. Comb of eighth abdominal segment with 20 to 30 scales in a patch. Air tube index 3.0 to 3.5. Pecten with 18 to 22 teeth on basal two-fifths of air tube; tuft usually triple, inserted beyond pecten at middle of tube. Anal segment with saddle extending three-quarters down the sides with spicules on apical third. Ventral brush large with 3 or 4 precratal tufts. Gills 114 to 21% times as long as saddle. DISTRIBUTION. Found in northern United States, Canada and Alaska. Recorded in Canada from Quebec to British Columbia (type locality, Rupert House, Que.). Ontario records show it to be commoner in the north and central parts of .the province; localities where it has been taken include Arnpricr, Brampton, Camp Borden, Kenora, Ottawa, Moose Factory, Nipigon and White River. BIOLOGICAL NOTES. The species breeds in temporary pools of snow water and rain water; it has been found in brackish water along the coast of Alaska. In Canada it is largely confined to coniferous forests of the northern parts of the province. Females bite readily in the evening, and in the woods at any time. Through most of its range the species is uncommon. 151 Aedes intrudens Dyar FEMALE. Medium sized species; wing length 4.0 to 4.5 mm. Proboscis and palps dark. Scutum uniformly golden-brown (Fig. 16), occasionally with faint median stripes. Scutellum with light brown setae on the lobes. Hypostigial scale patch present or absent. Lower mesepimeral bristles 1 to 5, rarely none. Postcoxal scale patch absent. Abdominal tergites brown to black, each with a basal white band wider at the sides. Tarsi dark. “This is the only dark-legged species (of Aedes) lacking postcoxal scales and having a uniform brown mesonotum.” (Vockeroth, 39). MALE, Terminalia as in Fig. 57. The sharp stump-like projection on the medial surface of the claspette stem, and the claspette filament, are distinguishing points. LARVA. (Fig. 119). Antenna slightly shorter than the head, dark towards apex; antennal tuft multiple, inserted near middle of antenna. Head hairs: Upper (5) 8- or 4-branched; lower (6) double or triple; postantennal (7) multiple. Comb of eighth abdominal segment with 12 to 16 teeth in an irregular double row. Air tube index 3.0. Pecten with 12 to 16 teeth on basal three-fifths of air tube, with 1 to 3 distal teeth detached; tuft 5- to 8-branched inserted near last pecten tooth. Anal segment nearly ringed by saddle; ventral margin of saddle notched. Ventral brush large, with 2 or 3 precratal tufts. Gills 114 to 214 times as long as saddle. DISTRIBUTION. A species of forests and woodlands, intrudens is known from northern North America and northern Europe. It is common ~ throughout the northern States, and is recorded from all provinces in Canada (type locality, White River, Ont.). Ontario records are few but will doubtless be increased with more collecting. It has been found at Algonquin Park, Apple Hill, Dryden, Moose Factory, Nipigon, Toronto and White River. BIOLOGICAL NOTES. Larvae are found in woodland pools, bogs and marshes. In central Ontario they are present from early May to early J ane adults from June to August. Females are persistent biters day and night. Aedes pionips Dyar FEMALE. A medium sized species; wing length 4.5 to 5.0 mm. Proboscis long, dark. Palps dark. Scutum yellow, with two broad (Fig. 17) submedian dark brown stripes and posterior half stripes. The two submedian stripes are separated by a narrow median line of yellow scales. Scutellum with black setae on lobes. Hypostigial scale patch absent. Lower mesepimeral bristles 1 to 4, rarely none. Postcoxal scale patch present, Abdominal tergites dark, each with a basal white band widening at the sides. Tarsi dark. | MALE (Fig. 58). For distinguishing characters, see communis. LARVA (Figs. 121, 122). Antenna shorter than head; antennal tuft multiple, inserted near middle of antenna. Head hairs: Upper (5) 4- to 6-branched; lower (6) 3- to 5-branched; postantennal (7) multiple. Comb of eighth abdominal segment with many (over 60) scales in a patch. Air tube broad near base, index 2.5. Pecten of 25 to 30 teeth on basal two- fifths of air tube; tuft 6- to 8-branched, inserted near middle of tube. Anal segment with saddle extending three-quarters down the sides. Ventral oe large, with 1 to 8 precratal tufts. Gills 114 to 2 times as long as saddle. 152 DISTRIBUTION. This species is found in Alaska, western United States and Canada, In Canada its range extends from Labrador to British Columbia, generally in the forests of the northern parts of the provinces. Ontario records show it to be a central and northern species (type locality, White River, Ont.), it having been found at Algonquin Park, Coral Rapids, Guelph, Kenogami River, Moose Factory, Nipigon and White River. BIOLOGICAL NOTES. Larvae are found in any of various types of ponds and pools found in woodlands and forest country. Larvae are present from mid-May to mid-June in Algonquin Park, and adults from mid-July to mid-August (8). Most workers agree that the species is rare or local. Aedes punctor (Kirby) FEMALE. A medium sized species; wing length 4.0 to 4.7 mm. Proboscis and palps dark. Scutum bronze, with a broad (Fig. 18) dark median stripe, often divided; usually a pair of dark areas lateral and posterior to the median stripe. Scutellum with light brown setae on lobes. Hypostigial scale patch absent. Lower mesepimeral bristles 1 to 5. Post- coxal scale patch present, Abdominal tergites dark, each with a basal white band, which is variable in extent. Tarsi dark. MALE. Terminalia as in Fig. 59. LARVA. (Fig. 120). Antenna short, about half as long as head; antennal tuft multiple, inserted before middle of antenna. Head hairs: Upper (5) and lower (6) single (rarely double) ; postantennal (7) 3- or 6-branched. Comb of eighth abdominal segment with 10 to 19 scales in an irregular row. Air tube index 3.0. Pecten of numerous closely spaced teeth on basal two-fifths of air tube; tuft of 3 to 5 branches inserted beyond the pecten. Anal segment completely ringed by saddle. Ventral brush large, with 1 to 3 precratal tufts. Gills 114 to 21% times as long as saddle. DISTRIBUTION. The range of A. punctor covers most of the northern hemisphere between: 45° and 70° N, it being found in northern Asia, Europe and North America. In Canada it is recorded from all provinces and territories, (type locality, McKenzie River Valley, near Ft. Norman, N.W.T.). One of the commonest species in Ontario, being found all over the province. The following list is a partial one of places where the species has been collected: Algonquin Park, Albany, Camp Borden, Coral Rapids, Dryden, Port Hope, Guelph, Ghost River, Height of Land, Kenagami, Kenora, Moosonee, Nipigon, Ottawa, Toronto, White River. BIOLOGICAL NOTES. Typically a woodland and forest species, larvae may be found in almost. any body of standing water, large or small, not only in shaded woods, but often in roadside ditches, marshes, etc. It is an early species and can withstand repeated freezing and thawing. In the south of the province, larvae may be found at the beginning of April, but are not seen much before late May in the north. Adults from collected larvae have emerged in the laboratory before the end of April, but in the field they are not seen before the middle of May in the south. They persist all summer, and may be taken biting as late as September. The females are persistent biters and on the whole this is one of the most abundant and annoying species in the province. Aedes riparius Dyar and Knab FEMALE. A medium to large species; wing length 4.6 to 5.2 mm. Proboscis dark, with scattered white scales. Palps dark with white scales at apices of segments. Scutum uniformly reddish-brown, rarely with faint indications of median stripe. Scutellum with brown setae on lobes. Hypo- 153 stigial scale patch present, with few to many scales. Lower mesepimeral bristles absent. Abdominal tergites dark, but with many white scales intermingled and merging into basal white bands. Tarsi with white bands only at bases of segments. MALE. Terminalia as in Fig. 60. The basal lobe of the basistyle is usually pointed. . LARVA. (Figs. 128, 124). Antenna only half as long as head; an- tennal tuft multiple, inserted before middle of antenna. Head hairs: Upper (5) and lower (6) both double; postantennal (7) 4- to 8-branched. Comb of eighth abdominal segment with 6 to 8 scales in a single irregular row. Air tube index 3.5. Pecten of 14 to 17 teeth on basal half of air tube, the distal 2 or 3 teeth detached ; tuft 3- to 5-branched, inserted beyond pecten. Anal segment with saddle extending three-quarters down sides. Ventral brush large, with 4 to 6 precratal tufts. Gills 114 times as long as saddle. DISTRIBUTION. A species of the northern plains, riparius is found in Siberia, Europe, the north and central United States, and in Canada from Ontario to Alberta (type locality, Winnipeg, Man.). Ontario however is probably outside its normal range, for the species is certainly rare in the province. Twinn (34) reports it in Ontario but gives no locality. One record from the Ottawa region is given in the 39th Annual Report of the Entomological Society of Ontario, 1908. BIOLOGICAL NOTES. There is a dearth of information on the biology of this species. On the prairies, larvae are found in grassland pools, in ditches and depressions in the vicinity of poplar and willow clumps. In Saskatchewan it is an early species, with adults flying from mid to late May (28). Aedes sticticus (Meigen) FEMALE. Small to medium species; wing length 3.3 to 4.2 mm. Proboscis and palps dark. Scutum yellowish-white with two well-defined dark brown median stripes. Posterior half stripes present. Scutellum with dark brown to black setae on lobes. Hypostigial scale patch absent. Lower mesepimeral bristles absent. Postcoxal scale patch absent. Abdominal tergites dark, with narrow basal white bands widening at the sides. Tarsi dark. MALE. Terminalia as in Fig. 62. LARVA. (Figs. 125, 126, 127). Antenna short, less than half as long as head; antennal tuft multiple, inserted before middle of antenna. Head hairs: Upper (5) 2- to 4-branched; lower (6) double; postantennal (7) multiple. Comb of eighth abdominal segment with 20 to 24 scales in a patch. Air tube index 2.5 to 3.0. Pecten with 15 to 20 teeth, on basal half of tube; tuft small, 4- to 6-branched, inserted beyond pecten. Anal segment nearly encircled by saddle. Ventral brush large, with 2 to 4 precratal tufts. Gills usually 2 to 214 times as long as saddle. DISTRIBUTION. Found in Siberia, northern Europe and North America. Recorded from almost all states and provinces in the United States and Canada. Ontario lists are few and scattered, but it has been taken at Coral Rapids,.Galt, Moose Factory, Moosonee and Ottawa. These records are too few to form an idea of its range, but it appears to be a minor species. BIOLOGICAL NOTES. Larvae are found in pools in woods and open country and in flood-water pools along streams and rivers. It is not a very early species, adults emerging in May and June. Smaller broods of larvae may develop later in the summer as a result of subsequent flooding. 154 Females may be found flying until September, and are persistent biters both during daytime and in the evening. Aedes stimulans (Walker) FEMALE. A medium sized species; wing length 4-3 to 4.8 mm. Proboscis and palps dark. Scutum golden brown, with faint median (Fig. 19) stripe, rarely well defined. Scutellum with dark brown setae on lobes. Hypostigial scale patch absent. Lower mesepimeral bristles usually 3 to 5. Abdominal tergites dark, each with a broad white basal band, usually widest at the centre. Hind tarsi with broad basal white bands on all segments; middle tarsi with basal white bands on segments 1 to 4; front tarsi with basal white bands on segments 1 to 3. MALE. Terminalia as in Fig. 63. The long petiole of the claspette filament is useful in separating the species from implicatus and others. LARVA. (Figs. 128, 129, 180). Antenna less than half as long as head; antennal tuft small, multiple, inserted near middle of-antenna. Head hairs: Upper (5) double; lower (6) single; postantennal (7) multiple. Comb of eighth abdominal segment with 25 to 35 scales in a patch. Air tube index 3.0 to 3.5. Pecten with 20 to 25 teeth on basal two-fifths of air tube; tuft 3- to 4-branched, inserted beyond pecten. Anal segment with saddle extending two-thirds down the sides. Saddle covered with spicules that are weakly developed basally and more strongly developed apically. Ventral brush large, with 2 to 4 precratal tufts. Gills as long or longer than the saddle. DISTRIBUTION. Known from Alaska, northern and central United States and Canada. In Canada reported from every province and territory (type locality, Nova Scotia). It is a common species throughout southern Ontario, becoming scarcer northward, and already absent in Algonquin Park (8). Localities where it has been taken include Aberfoyle, Arnprior, Brampton, Campbellville, Camp Borden, Cheltenham, Elora, Guelph, King- ston, London, Moose Factory, Niagara Falls, Orillia, Ottawa, Purpleville, Rockwood, St. Thomas, Stratford and Toronto. BIOLOGICAL NOTES. Larvae are found in snow water and rain pools in woodlands of every kind from early April to early June. While some report them associated with other larvae, the authors have usually found stimulans the chief or only species in a particular pool. Females are on the wing most of the summer; they are persistent biters and one of the most annoying species around the towns and villages of southern Ontario. Aedes trichurus (Dyar) FEMALE. Medium sized species; wing length 4.4 to 4.8 mm, Pro- boscis and palps dark. Scutum with brown and white scales intermixed, sometimes giving a uniformly grayish appearance, but sometimes showing a broad median stripe of predominantly brown scales. Scutellum with dark brown setae on lobes. Hypostigial scale patch present. Lower mesepimeral bristles 3 to 6. Postcoxal scale patch present. Abdominal tergites dark with basal white bands widening laterally. Tarsi dark. White “‘knee spots” absent. MALE. Terminalia as in Fig. 64, The claspette filament with its curved concentric folds, and the two setae near the tip of the claspette stem, are useful spots. LARVA. (Fig. 131) Antenna less than half as long as head; antennal tuft multiple, inserted before middle of antenna. Head hairs: Upper (5) double or triple; lower (6) single; postantennal (7) 5- or 6-branched. Comb of eighth abdominal segment with 12 to 18 scales in a double row. 155 Air tube index 3.0. Pecten with 16 to 20 teeth, the distal 4 or 5 detached, and extending to three-quarters the length of the tube; tuft 5- or 6- branched, inserted within the pecten near basal half of tube. Four or five branched dorsal tufts are present, this distinguishing the species from all others of the genus and resembling Culex, where however the tufts are lateral or ventral. Anal segment with saddle extending four-fifths down the sides. Ventral brush large, with about 3 precratal tufts. Gills about ~ twice as long as the saddle. . DISTRIBUTION. Limited to the northern United States and southern Canada. Generally distributed in Canada, being recorded from the Mari- times west to British Columbia, its type locality. In Ontario it appears to be found sporadically over the south and central parts of the province, as the following records show: Algonquin Park, Brampton, Camp Borden, Elora, Galt, Guelph, Ottawa and West Montrose. BIOLOGICAL NOTES. Larvae are found in woodland pools and swamps, sometimes associated with other species of Aedes. In Algonquin Park they are present from mid-May to early July (3). At Guelph they are found from early April to the end of May, by which time the first adults are on the wing. Aedes triseriatus (Say) FEMALE. A medium sized species; wing length 3.5 to 4.2 mm. Proboscis and palps black. Scutum with a broad (Fig. 20) median brown stripe widening posteriorly; the sides and margins of the scutum silvery white. Scutellum with a patch of white setae on middle lobe. Hypostigial scale patch absent. Lower mesepimeral bristles absent. Abdominal tergites bluish-black, with few or no white patches. Tarsi dark. MALE. Terminalia as in Fig. 65. Scales on basistyle longer than average. The long tapering claspette filament, as long or longer than the claspette stem, is diagnostic. The apical lobe of the basistyle is virtually absent, but is indicated by a dense patch of setae on the inner surface of the basistyle. LARVA. (Figs. 132, 1383). Antenna half as long as head, smooth; antennal tuft a single hair, inserted near middle of antenna, Head hairs: Upper (5) single; lower (6) 2- to 4-branched; postantennal (7) short, multiple. Comb of eighth abdominal segment with 8 to 12 scales in an irregular row. Air tube index 2.5 to 3.0 Pecten with 17 to 20 teeth reaching middle of the tube; tuft a single or double hair inserted beyond pecten. Anal segment with saddle extending two-thirds down the sides. Ventral brush large, with 2 or 3 precratal tufts. Gills with dorsal pair longer than ventral pair. DISTRIBUTION. A species typical of the eastern United States (type locality, Pennsylvania), but extending into Mexico and southern Canada. Canadian records are from British Columbia, Ontario, Quebec and Saskatchewan. In Ontario it has been collected at Algonquin Park, De ~ Grassi Point, Jordon, London and Toronto. BIOLOGICAL NOTES. The typical and most usual breeding place of this species is in tree holes, but larvae may be found in a variety of artificial containers and have also been taken from pitcher plants. Adults are flying in July, and bite readily in the daytime. Judd (19) found them attracted to light traps. - Aedes trivittatus (Coquillett) FEMALE. Medium sized species; wing length 3.5 to 4.0 mm. Pro- boscis and palps dark. Scutum with two light yellow stripes (Fig. 21) 156 separated by a median brown stripe of equal width. Scutellum with brown setae on the lobes. Hypostigial scale patch absent. Lower mesepimeral bristles absent. Abdominal tergites dark with small white patches at the sides. Tarsi dark. MALE. Terminalia as in Fig. 66. The claspette with its backwardly directed spine and denticles is diagnostic. LARVA. (Fig. 134). Antenna short, less than half as long as head; antennal tuft multiple, inserted near middle of antenna. Head hairs: Upper (5) and lower (6) both single; postantennal (7) multiple. Comb of eighth ~ abdominal segment with 18 to 26 scales in a patch. Air tube stout, index 2.0. Pecten of about 14 to 18 teeth, reaching beyond middle of air tube; tuft 4- to 9-branched, inserted beyond pecten. Anal segment completely ringed by saddle, which is wider than long. Ventral brush large with no precratal tufts. Gills 2 to 3 times as long as saddle. DISTRIBUTION. A North American species, known from most of the United States east of the Rocky Mountains, Mexico and southern Canada. In Canada records are limited to Nova Scotia, and to Ontario where Judd (19) found it at London. Twinn (34) also places it in Ontario. BIOLOGICAL NOTES. Larvae are found in early summer in wood- land pools and swamps. Females are persistent biters both by day and evening. Typically a species of semi- -open or lightly wooded areas, rarely found in forests. Uncommon in the province, but probably more general than the above records indicate. Aedes vexans (Meigen) FEMALE. A small to medium species; wing length 3.5 to 4.0 mm. Proboscis and palps dark. Scutum uniformly covered with golden brown scales, paler on margins. Scutellum with light brown setae on the lobes. Hypostigial scale patch absent. Lower mesepimeral bristles absent. Post- coxal scale patch absent. Abdominal tergites dark, each with a conspicuous indented basal white band, sometimes separating into two patches. Hind tarsi with narrow basal white bands on all segments, Front and middle tarsi with narrow basal white bands only on segments 1 to 3, reduced or absent on segments 4 and 5. MALE. Terminalia as in Fig. 67. The broad flattened disistyle with its terminal claw, and the tuft of short setae on the claspette, are diagnostic. LARVA. (Fig. 135). Antenna half as long as head; antennal tuft multiple, inserted near middle of antenna. Head hairs: Upper (5) 3- to 5-branched; lower (6) double or triple; postantennal (7) multiple. Comb of eighth abdominal segment with 10 to 12 scales in an irregular row. Air tube index 3.0 to 3.5. Pecten with 14 to 20 teeth, reaching middle of tube, with 1 to 3 teeth detached distally; tuft small, 3. to 6-branched, inserted beyond pecten. Anal segment with saddle extending nearly to ventral line. Ventral brush large, with 4 or 5 precratal tufts. Gills about twice as long as saddle. DISTRIBUTION, A cosmopolitan species found in Europe, Asia, Africa, the Pacific Islands and North America. In the United States it is known from nearly every state; and in Canada across the whole southern part of the country. In southern Ontario it is one of the commonest species, becoming scarcer northwards. Provincial records include: Aberfoyle, Al- gonquin Park, Ancaster, Brampton, Camp Borden, Cochrane, Dryden, Elora, Galt, Kenora, Kingston, London, Ottawa, Toronto and White River. BIOLOGICAL NOTES. Larvae are found in any small body of stand- ing water, in the woods or in the open. The species is a later one than most others of the genus, and larvae are commonest from May to June at a time 157 when many of the small pools in which they are found are nearly dry. Adults may be found throughout the summer and are always troublesome biters. They often invade buildings and houses in the evening, and are attracted to light traps. Rains in late summer produce numerous larvae in August and September, and where conditions are favourable a succes- sion of generations may be produced in a season. NOTE. In addition to the species of Aedes described above, there is in the National Collection at Ottawa a single female of A. spencerii Theo., taken at Carleton Place. This is typically a prairie species, and there appear to be no other records of it from Ontario. "LABLE & Presence of selected key characters in the larvae of Ontario species of Aedes. -+ character present, — character absent A Number of scales gone Antenna Tuft of eee on 8th abdominal _— Hair hairs shorter air tube some yen 2 ringed segment Upper Lower detachea head 20 30 abserratus atropalpus aurtf er barri campestris cinereus decticus diantaeus EXCTUCIANS intrudens TIpAarius trichurus VexAaNS flavescens canadensis communis dorsalis fitchu impiger implicatus pionips — punctor — sticticus — stimulans — trisertatus — trivittatus — Tens esas 3 bo Ne i pel eT O1w W bo oo We OUD Li) f go bo by i) i Jt 1) ) e+e t+tt++4+4t4+ : EEN ANONEFAHEPHE DAMON ANANDOWNWHE raises HK REDD OHH WHE MWWHENWNWNOHNNHE DO ka > PP eT Pte PP bE IT Pe tt+4+t+4+++4+4++4+4+44+44+4+4 | 4++++ 14+ te pepo Weel ec eae Pal? toa As this paper goes to press, a letter from Dr. J. R. Vockeroth, Ottawa, informs us that he has recently found Aedes barri Rueger at Marmora, Orillia and Smith’s Falls, and believes it will be found to be widespread in Ontario. This species was first described in 1958 (J. Kans. Entomol. Soc., 158 no. 1) by M. E. Rueger, and is also figured by Barr (1). The following brief description is taken from Barr. Female, resembles excrucians, but has a shorter tarsal claw without bend or kink; the scutum is coppery with white lines or spots, occasionally with a well-defined median stripe; lower mesepimeral bristles absent; lower one-fifth of mesepimeron without scales; postcoxal scale patch present; pale “knee spots” present on legs; wings with both light and dark scales. According to Barr, the species is difficult to separate from the others with basal white bands on the tarsi, i.e., excrucians, fitchit, riparius and stimulans. The male terminalia closely resemble those of excrucians. The principal larval characters are given in Table I. Genus CULEX Linnaeus Culex is chiefly a tropical and sub-tropical genus. Only three species are found in the province. Females can usually be distinguished from those of Aedes by the rounded abdominal tip (Fig. 3). The female tarsal claws are without teeth (Fig. 69). In the male terminalia the claspette is absent and there is no basal lobe on the basistyle. Larvae are somewhat similar to those of Aedes, but the long air tube with its tufts is diagnostic. In all these three species the adults hibernate, often in basements and other warm buildings, emerging in spring. Larvae appear later in the year than do those of Aedes, usually being commonest in June when water temper- atures have risen. KEYS TO SPECIES FEMALES 1. White basal (anterior) bands on abdominal tergites .................... 2 White apical (posterior) bands on abdominal tergites ........ territans 2. Scutum covered with uniformly golden coarse scales ................ pipiens Scutum covered with fine scales, usually with two pale spots near the LTE RS RS Oem ep ee Coie aa ee ees EES, restuans MALE TERMINALIA 1. Apex of tenth sternite with a single row of short blunt spines. Apical lobe of basistyle without a large broad leaflet .........0.000000....... territans Apex of tenth sternite covered with dense patch of short spines. Apical Iobe of basistyle with a large broad leaflet (Figs. 70, 71) ............ 2 2. Phallosome of several plates, strongly sclerotized ................... pipiens Phallosome simple, of two curved plates, not strongly sclerotized ...... er pe ee ett ONS eo ht nak ise ee ay Roe, restuans LARVAE (FOURTH INSTAR) 1. Tufts on air tube multiple. Antenna with tuft in a constriction near pate CHEE O Oir Shiiie es 2 Most tufts on air tube reduced to long single hairs. Antenna uniform, not constricted, with antennal tuft inserted near middle of shaft Bee a eS ee id Een ee pee a ielr ose ok Sar a tee ht ON OSL IOS 2. Air tube long, index 6.0 to 7.0. Pecten with 12 to 16 teeth; 4 or 5 pairs of tufts beyond pecten, the apical tuft not in line with the others Pipes yee mee ae se oy Nite ee Ss oe Se territans Air tube not so long, index 4.0 to 5.0. Pecten with 6 to 13 teeth, 4 or 5 pairs of tufts beyond pecten, subapical tuft inserted laterally Ue een ee oP ce ey ee Ronin be ee RF oy Loe pipiens Culex pipiens Linnaeus FEMALE. A medium small species; wing length 3.5 to 4.0 mm. Proboscis and palps dark. Scutum uniformly golden brown. Scutellum with brown setae on lobes. Abdominal tergites dark, with metallic bronze to blue reflections; basal white bands on each segment. Legs dark, with metallic reflections. | MALE. Terminalia as in Fig. 68. The presence of a flat leaf-like seta on the basistyle distinguishes this species from territans, and its complex phallosome from restuans. LARVA. (Fig. 136). Antenna shorter than head, constricted beyond antennal tuft; tuft large, multiple. Head hairs: Upper (5) and lower (6) 4- to 6-branched; postantennal (7) multiple. Comb of eighth abdominal segment with 35 to 50 scales in a triangular patch. Air tube index 4.0 to 5.0. Pecten with 6 to 12 teeth on basal third of tube; usually 4 pairs of tufts inserted beyond pecten. Anal segment completely ringed by saddle. Ventral brush large, no precratal tufts. Gills about 114 times as long as the saddle. DISTRIBUTION. A species of world-wide distribution, being found on all continents between 60°N and 40°S. Found throughout the United States and most of southern Canada. In Ontario the species is fairly com- mon in the southern parts only, being unrecorded from the central and northern areas. It has been collected at Ancaster, Brampton, Guelph, King- ston, London, Ottawa, St. Thomas, Stoney Creek, Toronto, Trenton. BIOLOGICAL NOTES. Through long association with man this species may be considered domestic. Larvae breed in rain barrels and every kind of artificial container, and also in temporary and permanent pools (19). Adults are never found far from human habitations, the females infesting houses and being troublesome biters at night. During winter months the adults hibernate in basements, caves, etc. Larvae are most abundant in June, and adults may be found throughout the summer. They are attracted to light traps. This species is a useful experimental insect exe a be reared continuously in the laboratory. See McLintock (25) for etails. Culex restuans Theobald FEMALE. A medium sized species; wing length 4.0 to 4.5 mm. Proboscis and palps dark. Scutum golden-brown; usually with a pair of small pale spots near the middle. Scutellum with brown setae on lobes. Abdominal tergites dark brown, each with a basal whitish-yellow band. Legs dark, with metallic bronze to blue reflections. MALE. Terminalia as in Fig. 70. The apical lobe has three rods, and a broad leaf-like seta. LARVA. (Fig. 137). Antenna about half as long as head, only slightly narrowed beyond tuft; tuft multiple, inserted near middle of antenna. Head hairs: Upper (5) and lower (6) 4- to 6-branched; post- antennal (7) multiple. Comb of eighth abdominal segment with 35 to 40 scales in a patch. Air tube index 4.0 to 5.0. Pecten with 12 to 20 teeth; about 5 to 7 single hairs irregularly placed along the air tube, and two subapical tufts of 2 or 3 branches inserted beyond pecten. Anal segment completely ringed by saddle, which has patches of small spines on dorso- posterior area. Ventral brush large, with no precratal tufts. Gulls 2 tos times as long as saddle. DISTRIBUTION. Known from Mexico, most of the United States and southern Canada (type locality, Toronto, Ont.). In Canada, found from 160 Quebec to British Columbia. Ontario records are few, including only Aberfoyle, Algonquin Park, London, Ottawa, Stratford, and Toronto. BIOLOGICAL NOTES. Larvae may be found from June to September in many different habitats, such as woodland pools, stagnant ditches and artificial containers. Adults may be taken throughout the summer, but are never numerous; they overwinter in sheltered places. Workers are not agreed on the biting habits of this species; some regard it as troublesome, while others believe it seldom attacks man. Culex territans Walker FEMALE. A medium sized species; wing length 4.0 to 4.6 mm. Pro- boscis and palps dark. Scutum golden-brown, often with a pair of small pale spots near the middle. Scutellum with brown setae on the lobes. Ab- dominal tergites bluish-black, with narrow white bands on the apical (posterior) margins. MALE. Terminalia as in Fig. 71. The apical lobe is narrow and prominent, with only two wide rods. LARVA. (Figs. 138, 1389). Antenna as long as head, constricted beyond tuft; tuft large, multiple, inserted at distal third of antenna. Head hairs: Upper (5) and lower (6) single (rarely double); postantennal (7) multiple. Comb of eighth abdominal segment with about 40 scales in a patch. Air tube long, slender, index 6.0 to 7.0. Pecten of 12 to 16 teeth on basal third of tube; 4 or 5 pairs of tufts inserted beyond the pecten, the smaller apical tuft inserted laterally to the others. Anal segment com- pletely ringed by saddle. Ventral brush large, with 2 or 3 precratal tufts. Gills usually as long or longer than the saddle. DISTRIBUTION. Occurs in Asia, Turkey, North Africa, Europe, Alaska, United States and Canada. In the United States it is found over most of the country east of the Rocky Mountains. Canadian records show it to be present from Ontario to British Columbia. In the past it has been confused with apicalis, a species restricted to the southwestern United States and Mexico. Most records of apicalis in eastern Canada undoubtedly refer to territans. In Ontario the species is known from Arkell, Algonquin Park, Kingston, Marden, Ottawa, Puslinch, London, Toronto, Trenton and White River. Thus it appears to be present over most of the south of the province, but is never very common anywhere. BIOLOGICAL NOTES. Larvae are found in permanent and tem- porary pools and in swamps and bogs often throughout the summer, being taken in Algonquin Park and at London until late August (3, 19). Females feed on frogs and other cold-blooded vertebrates and are not known to bite man. NOTE. In addition to the species of Culex described above, there is in the National Collection at Ottawa a single female of C. tarsalis Coq. from Algonquin Park. This is typically a western species, and no other record is known at present from Ontario. SUMMARY A total of forty-five species of Culicidae are recorded from the province of Ontario. Keys to males, females and fourth instar larvae of these species, comprised in eight genera, are given, with notes on distribution and biology. The paper includes 139 text figures and one table of larval characters. ACKNOWLEDGEMENTS The assistance of Dr. J. R. Vockeroth, of the Entomology Research Institute, Ottawa, in critically reading this paper and suggesting correc- 161 tions and improvements is gratefully acknowledged. We are also indebted to him for information on four species of mosquitoes in the National Collection (mentioned above in notes at the end of each appropriate genus), whose presence in the province was previously unknown to us. 15. 16. LZ. 18. 19. BIBLIOGRAPHY BarRR, A. R. (1958). The mosquitoes of Minnesota (Diptera: Culi- cidae: Culicinae). Univ. Minn. Agric. exp. Sta., Tech. Bull. 228. BECKEL, W. E. (1954). The identification of adult female Aedes mosquitoes (Diptera: Culicidae) of the black-legged group taken in the field at Churchill, Manitoba. Canad. J. Zool. 32: 324-330. . BECKEL, W. E. and ATwoop, H. L. (1959). A contribution to the bionomics of the mosquitoes of Algonquin Park. Canad. J. Zool. 37: 163-110. CARPENTER, 8S. J. and LACASSE, W. J. (1955). Mosquitoes of North America (north of Mexico). Univ. Calif. Press. DopbcE, H. R. (1947). A new species of Wyeomyia from the pitcher plant. Proc. ent. Soc. Wash. 49: 117-122. DyAr, H. G. (1921). The mosquitoes of Canada (iaeerae Culicidae). Roy. Canad. Inst. Trans: 732 Fi-120- DyAR, H. G. (1922). The mosquitoes of the United States. Proc. U.S. nat. Mus. 62: 1-119. FREEMAN, T. N. (1952). Interim report of the distribution of the mosquitoes obtained in the northern insect survey. Can. Defense Res. Board, Tech, Rep. I. . GIBSON, A. (1934). Mosquito suppression work in Canada in 19338. N.J. mosq. Exterm. Ass. Proc. 21: 102-112. GIBSON, A. (1937). Mosquito suppression work in Canada in 1936. N.J. mosq. Exterm. Ass. Proc. 24: 96-108. . GIBSON, A. (1941). Mosauito suppression work in Canada in 1940. N.J. mosq. Exterm. Ass. Proc. 28: 167-176. . HEARLE, EF. (1920). Notes on some mosquitoes new to Canada. Canad. Ent. 52: 114-116. . HINMAN, E. H. and HURLBUT, H. S. (1942). A collection of Anopheline mosquitoes from southern Ontario. Ganad. Ent. 727 20: . HOCKING. B., RICHARDS, W. R. and TWINN, C. R. (1950). Observations on the bionomics of some northern mosquito species (Culicidae: Diptera). Canad. J Res., D: 28: 58-80: HOWARD, L. O., DYyAR, H. G. and KNAB, F. (1912-1917). The mosqui- toes of North and Central America and the West Indies. Publ. Carneg,. Instn. 4 vol., 159: 1,064 pp. JENKINS, D. W. and KNIGHT, K. L. (1950). Ecological survey of the mosquitoes of Great Whale River, Quebec (Diptera: Culicidae). Proc, ent; Soc, Wash. 52: 209-223. JENKINS, D. W. and KNIGHT, K. L. (1952). Ecological survey of the mosquitoes of southern James Bay. Amer. mid. Nat. 47: 456-468. JUDD, W. W. (1950). Mosquitoes collected in the vicinity of Hamilton, Ontario, during the summer of 1948. Mosquito News, 10: 57-59. JUDD, W. W. (1954). Results of a survey of mosquitoes conducted at London, Ontario, in 1952 with observations on the biology of the species collected. Canad. Ent. 86: 101-108. 162 20. 21. 22. 23. 24. 25. 26. 27. 28. Zo. 30. 31. 32. 35. 34. 35. 36. 37. o8. 39. 40. KNIGHT, K. L. (1951). The Aedes (Ochlerotatus) punctor subgroup oT North America (Diptera: Culicidae). Ann. ent. Soc. Amer. 44: MATHESON, R. (1944), A handbook of the mosquitoes of North America. Ithaca, N.Y. Comstock Publ. Ass. MCLAINE, L. 8S. (1943). Mosquito suppression work in Canada in 1942. N.J. mosq. Exterm, Ass. Proc. 30: 51-56. McLINTOcK, J. (1944). The mosquitoes of the greater Winnipeg area. Canad. Ent. 76: 89-104. McLINTock, J. (1952). Continuous laboratory rearing of Culiseta inornata (Will.) (Diptera: Culicidae). Mosquito News, 12: 195-201. McLINTOCK, J. (1960). Simplified method for maintaining Culex pipiens Linnaeus in the laboratory (Diptera: Culicidae). Mosquito News, 20: 27-29. OZBURN, R. H. (1944). Preliminary report on Anopheline mosque survey in Canada. Proc, ent. Soc. Ont. 75: 37-44. REMPEL, J. G. (1950). A guide to the mosquito larvae of western Canada. Canad. J. Res., D.28: 207-248. REMPEL, J. G. (1953). The mosquitoes of Saskatchewan. Canad. J. Zool, 31: 483-509. SMITH, M. E. (1952). A new northern Aedes mosquito, with notes on its close ally Aedes diantaeus Howard, Dyar and Knab (Diptera: Culicidae). Bull. Brooklyn ent. Soc. 47: 19-40. STONE, A., KNIGHT, K. L. and STARCKE, H. (1959). A synoptic catalog of. the mosquitoes of the world (Diptera, Culicidae). The Thomas Say Foundation. Vol. VI, 1959. TWINN, C. R. (1926). Notes on the mosquitoes of the Ottawa district. Canad. Ent. 58: 108-111. TWINN, C. R. (1935). A summary of insect conditions in Canada in 1935. Proc. ent. Soc. Ont. 66: 80-95. TWINN, C. R. (1945). Report on a survey of Anopheline mosquitoes in Canada in 1944. N.J. mosq. Exterm. Ass. Proc. 32: 242-251. TWINN, C. R. (1949). Mosquitoes and mosquito control in Canada. Mosquito News, 9: 35-41. URQUHART, F. A. (1948). A survey of the mosquitoes of the Toronto region made during the year 1948, Report submitted to the Board of Health, Toronto, Ontario. VOCKEROTH, J. R. (1950). Specific characters in tarsal claws of some species of Aedes (Diptera: Culicidae). Canad. Ent. 82: 160-162. VOCKEROTH, J. R. (1952). The specific status of Aedes pionips Dyar (Diptera: Culicidae). Canad. Ent. 84: 243-247. VOCKEROTH, J. R. (1954a). Notes on northern species of Aedes, with descriptions of two new species (Diptera: Culicidae). Canad. Ent. 86: 109-116. VOCKEROTH, J. R. (1954b). Notes on the identities and distributions of Aedes species of northern Canada, with a key to the females (Diptera: Culicidae). Canad. Ent. 86: 241-255. WISHART, G. and JAMES, H. G. (1945). Notes on the Anopheline mosquitoes of the Kingston, Trenton and Peterborough, Ontario, * areas. Proc. ent. Soc. Ont. 76: 39-48. 163 I) A. campestris I | IQ A.stimulans 20 A. triseriatus 2| A.trivittatus Figs. 10-21. Mesonotal patterns of several species of Aedes. 164 p | Lower Head Hair a ostclypeal Hair =+Upper Head Hair Eighth Abdominal Dorsal Brush Anal Gills Fig. 22. Diagram of dorsal aspect of head of Aedes larva. Fig. 23. Diagram of terminal segments of Aedes larva. 165 A. earlei J Leaflets of Phallosome 24 A. punctipennis Lobe of Oth e/ Henge A. walkeri 30 U. sapphirina Phallosome Site Figs. 24-27. Male terminalia of Anopheles. Figs. 28, 29. Male ter- minalia and postnotum of Wyeomyia. Fig. 30. Male terminalia of Uranotaenia. 166 3] C. alaskaensis Ne Ly \ it Figs. 31, 32. Male terminalia of Culiseta. 167 AY Wii 34 NS WZ C.morsitans BU 35 M.perturbans i \) Mt yw Figs. 33, 34. Male terminalia of Culiseta. Fig. 35. Male terminalia of Mansonia. 168 Eo) P. ciliata Figs. 36, 37. Male terminalia of Psorophora. 169 — 39 A.atropalpus A. aurifer Figs. 38-41. Male terminalia of Aedes. Fig. 42. Tarsal claw of female Aedes campestris D. and K. 170 ahs sort A. canadensis AA A. cinereus J \ t, N BN k 4 j, sy UE ye , Y, sy Say Fah ie 7 BN (ss| Ss y bec t ( \ " ie Ah Lieve ty, 4 i al Wy, 2 it ior Ba r aS L jptiis PUA etn ] Lanai ‘ ia 3 OM y i \ ; S Ue \\\\f Np 7 Se Sie. \ b/ N 5 3S wal 2 Lee “ . \\ Lua \ Se CD i > : G Pel) / '\ = ara rei . Ew e Near eel eng x , 4 NaN \ Nyy Vas ntrudens ee Z SSS e | ~ (ene un .; > iS QOS . y ‘ ey i i ; ‘ meer , Nee Figs. 53, 55, 56, 57. Male terminalia of Aedes. Fig. 54. Female tarsal claw of Aedes flavescens (Miiller) 173 (Tp) eee! yf = o Q ee <6 O © , D9, 60, 62. Male terminalia of Aedes. Fig. 61. Female tarsal claw of Aedes riparius D. and K. 58 Figs, 174 LPN 4 MAY... vA : Ce AY frichurds.) Vy & OV N X SS —S A. triseriatus A. trivittatus Figs. 63-66. Male terminalia of Aedes. 175 C.territans C.restuans Figs. 68, 70, 71. Male terminalia of Culex. Fig. 69. Female tarsal claw of Culex pipiens L. 176 3 Inner Clypeal Hair We Z CAS LOX RED ZZ ee 75 iS t A.earlei A. punctipennis ZS r. oe 76 Ta aoa A. quadrimaculatus A. walkeri ; re SQ) : W. smithii | Fig. 72. Dorsal aspect of head of Anopheles larva. 19 Fig. 73. Terminal segments of Anopheles larva. Figs. 74-77. Inner clypeal hairs (2) of Anopheles larvae. Figs. 78, 79. Terminal segments and head of Wyeomyia larva. 177 80 _U. sapphirina | | 8 M. perturbans So"): D ciliata 84 P. ferox p Fig. 80. Terminal segments of Uranotaenia larva. Fig. 81. Terminal segments of Mansonia larva. Fig. 82. Anal segment of Psorophora. larva. Figs. 83, 84. Air tubes of Psorophora larvae. 178 C.morsitans GD C.impatiens Ginernaia C.alaskaensis Figs, 85, 86. Head and air tube of Culiseta morsitans (Theo.) larva. Figs. 87, 89. Air tube and head of Culiseta inornata (Will.) larva. Figs. 88, 90. Heads of Culiseta larvae. IGS} je} | 92 A. abserratus A. atropalpus A. aurifer Figs. 91-93. Terminal segments of Aedes larvae. Fig. 94. Head of Aedes aurifer (Coq.) larva. 180 A. canadensis Figs. 95, 96, 99. Terminal segments of Aedes larvae. Figs. 97, 98. Comb scale and head of Aedes canadensis (Theo.) larva. Fig. 100. Head of Aedes cinereus Meig. larva. 181 A. communis 104 A. decticus Figs. 101, 104, 105. Terminal segments of Aedes larvae. Figs. 102, 103. Comb scale and head of Aedes communis (DeG.) larva. Fig. 106. Head of Aedes diantaeus H. D. and K. larva. 182 GEE BEE yee” voy KG —— A = een AS WS yu S— dd dopd> A Wai = () H \\, ve es MAY Te lO7 lO8 A. dorsalis lOO excrucians Figs, 107, 109. Terminal segments of Aedes larvae. Fig. 108. Comb scale of Aedes dorsalis Meig. larva. 183 He Wie MH anh) Vie ‘ = A. impiger i Figs. 110, 111, 114. Terminal segments of Aedes larvae. Fig. 112. Comb scale of Aedes fitchii (F. and Y.) larva. Figs. 113, 115. Comb scale and head of Aedes impiger (Walk.) larva. 184 9 t ARIS . 77g X yO G IN 117 f \ A.implicatus 8 | IN I6 A. punctor 19 4 az A. pionips Figs. 116, 119, 120. Terminal segments of Aedes larvae, Figs. 117, 118. Comb scale and head of Aedes implicatus Vock. larva Figs. 121, 122. Head and comb scale of Aedes pionips Dyar larva. 185 A. stimulans I30 A. trichurus I29 Figs. 123, 125, 128, 131. Terminal segments of Aedes larvae. Fig. 124. Head of Aedes riparius D. and K. larva. Figs. 126, 127. Comb scale and head of Aedes sticticus (Meig.) larva. Figs. 129, 130. Head and comb scale of Aedes stimulans (Walk.) larva. 186 Figs. 132, 134, 135. Terminal segments of Aedes larvae. Fig. 133. Head of Aedes triseriatus (Say) larva. 187 C. pipiens C.restuans Figs. 136-138. Terminal segments of Culex larvae. Fig. 139. Head of Culex territans Walk. larva. 188 THYMELICUS LINEOLA (OCHS.) (LEPIDOPTERA: HESPERIIDAE) A PEST OF HAY AND PASTURE GRASSES IN SOUTHERN ONTARIO’ D. H. PENGELLY INTRODUCTION The family Hesperiidae contains about 3000 species (1) and of these over 200 have been found in North America. The larvae are said to feed on a wide variety of plants, including cereals and grasses. The field skipper, Atalopedes campestris (Bud.) is one of the grass feeders and is the only one reported previously as damaging cultivated crops (10). In 1956 a report of extensive damage to hay and pasture crops was received from the Markdale area in Grey County, Ontario. An earlier and more timely report was received in 1957 and from larvae collected, the Essex skipper, Thymelicus lineola was reared and identified. This insect is referred to as Adopaea lineola by some authors, especially those in North America (3, 4, 6, 7, 8). According to Holland (3) this species is native to Europe. Although present in England, it was not recognised until 1890 because of its marked similarity to the little skipper, T. sylvestris (2). T. lineola was first recorded in North America by Saunders (7) in 1916. Ten battered speci- mens were taken in the vicinity of a refuse dump at London, Ontario in 1910. In 1911 a few adults were found in a vacant lot over-run with twitch grass, most of which was said to have been killed. In 1914, the species was found five miles from the original site of capture and by 1916 it was reported to be more widespread and more common. No further report was made on this insect until 1931, when Rawson (6) had it identified from specimens taken near Detroit in 1927. By 1930 it was very abundant in parts of Wayne County, Michigan. A single speci- men was taken at Findlay, Ohio. In the Nursery Inspection section of the 1949-1950 Report of the Canadian Minister of Agriculture, reference was made to a single specimen taken at Islington, Ontario. Matthewman et al (5) reported its presence again in the Toronto area in 1955. Studies were made in 1958 and 1959 to obtain information on the general biology of this insect, on its distribution and its importance as a pest of native and cultivated grasses. PROCEDURES Periodic sweeping of the grasses of pasture and hay fields was begun in early May. The earliest date on which larvae were found was May 13, 1958 at Bradford. These were second-instar forms. Individual larvae from sweeps were placed in shell vials with loose-fitting corks and fresh grass was supplied daily. The growth of moulds was inhibited by the periodic transfer of larvae to clean vials, and the removal of old grass, faecal pellets and cast skins every three days under normal rearing conditions. Larvae from collections made throughout the season were placed in rearing cages and from which information on parasites, larval mortality, and on other general aspects of their biology was obtained. Reared and field-caught adults were placed in screened cages and supplied with flowering plants as a source of food and with clumps of grass for oviposition sites. 1Contribution of the Department of Zoology, Ontario Agricultural College, Guelph, Canada. Proc. ent. Soc. Ont. 91 (1960) 1961 189 row Femoles Figures 1-8. 1. Adult skippers congregated in damp area on a roadside. 2. Feeding damage and tunnels of skipper larvae on orchard grass (x .75). 3. Eggs of TJ. lineola under blade sheath of timothy (x 10). 4, Adults of T. lineola (x .75). 5. Pupae, sixth-instar larva (full grown), 190 | DESCRIPTION OF STAGES Adults A detailed description of the adult forms is available in the paper by Rawson (6). They have a wing span of about 25 mm. Their wing colour is a bright orange and thin black lines are evident along some of the veins. Males are distinguished by their more slender abdomens and the prominent black dash on the basal portion of the forewings (Fig. 4). Egg The egg of T. lineola viewed from above was oval in outline and measured 1.0 mm. by 0.66 mm. It was dorso-ventrally flattened and gener- ally slightly concave or depressed in the middle (Fig. 3). The average thickness of the egg was 0.83 mm. The chorion was white, tough, sub- opaque, and covered with a fine reticulate sculpturing on the dorsal surface. First-instar larva The specimens of this stage examined were those removed from eggs. The body of the larva was yellowish-white in colour. The head capsule was jet black and on the prothorax was a prominent brown cervical shield. The length of the larva was 1.5 mm. and the head capsule width averaged 0.383 mm. Second-instar larva This form resembled the former in having a black head and a well defined cervical shield but the body was a greenish colour as a result of the feeding. Down the centre of the back was a narrow, dark, longitudinal stripe. A whitish or yellowish subdorsal stripe was present on either side of the centre line a short distance from it. In some instances two thicker white stripes were present between the dorsal and subdorsal stripes in the region of the thorax. The body length averaged 3.5 mm. and the head capsule 0.55 mm. in width and 0.5 mm. in length. Third-instar larva The head of this larva was a light brown colour with two whitish patches on the occiput. The stripes on the abdomen were similar to those of the second-instar larva. Body measurements were extremely variable, depending on the amount of feeding activity. The head capsule measure- ments averaged 0.8 mm. wide, by 0.7 mm. long Fourth, Fifth, and Sixth-instar larvae The only obvious difference among these forms was in their size (Figs. 5, 7). Beginning with the fourth-instar, the yellowish occipital patches of the head extended forward as longitudinal stripes to the area below the branching of the frontal suture. The average widths of the head capsules of these forms were 1.2 mm., 1.8 mm., and 2.2 mm. respectively. Pupa The thorax of the pupa, when first formed, was green in colour similar to the larva, but the abdomen was a yellowish green. The longi- tudinal stripes present on the larva were very pronounced on the abdomen of the pupa but only faintly so on the thorax (Fig. 5). The head bore a strong frontal projection or horn which curved downward slightly (Fig. 5). and fifth-instar larva (x 1.3). 6. Adult skippers feeding on flowers of thistle (x .75). 7. Fifth- and sixth-instar larvae (x 1.3). 8. Damage to timothy head by skipper larva (x .75). 19 GENERAL BIOLOGY Overwintering The eggs were laid during the first three weeks of July. Within 18 to 20 days of oviposition, fully developed, active larvae were present within the chorion of the eggs. These larvae remained inside until the following spring. Emergence Eggs collected in 1958 were stored out-of-doors until May 1, 1959. At that time, larvae inside the chorion were active but none emerged, Second- instar larvae were found in the field on May 138, 1958, and May 20, 1959. Later stages were present also, indicating that the larvae began to emerge sometime during the first week of May. Host plants The larvae of T. lineola appeared to be restricted to certain grasses, but they might feed on the leaves of leguminous plants when other food is scarce. The grasses on which the larvae have been collected are: Phlewm pratense L. (timothy) ; Dactylis glomerata L. (orchard grass) ; Agropyron repens L. (twitch grass); Loliwm perenne L. (perennial rye); Festuca elatior L. (meadow fescue). Larvae have been reared on Bromus inermis Leyss (brome grass) but field data concerning brome need substantiation. From one timothy field that was heavily infested, larvae moved to an adjacent oat crop. Here the feeding was of minor importance with only the edges of the lower blades showing signs of larval feeding activity. In the Priceville area there was evidence of larvae feeding on Carex sp. and one of the sedges. It is doubtful, however, if these plants served as ovi- position sites. Immature Stages First-instar larvae were not found in the field, thus no information is available on their behaviour, on feeding habits or on the duration of this stadium. Only a few second stage larvae were collected. These were reared and the second stadium lasted for five to six days. Since they were already in the second stadium when collected, this represents the lower limit of the duration. During this stage, the larvae ate relatively little as compared to other stages. Of the total surface area of grass blade eaten, the second- instar larvae devoured about 0.5 sq. cms. or 1.64 per cent. In the field, second-instar forms were located on the grass blades. Here they formed protective tubes or tunnels by drawing the edges of the blades © together and tying them with silk (Fig. 2). Feeding was confined to the edge of the blade a few centimetres from either end of the tunnel (Fig. 2). The tubes made by the second stage larvae were near the tip of the blade where it was narrow enough for these smaller larvae to carry out the process. The habits of the third-instar larvae were very similar to those of the second. They remained within the tunnel and fed on the blade near it. The amount of feeding increased to 3.28 per cent of the total during this stage. The duration of the third stadium varied from six to eight days. Fourth-instar larvae accounted for 6.56 per cent of the grass eaten and, as with the others, lived within the tunnel. This tunnel, in some cases, was a new one, since with increased feeding the end of the blade could be severed and the original tunnel lost. The fourth stadium lasted for five to eight days with one exception where it was only two days. 192 Fifth- and sixth-stage larvae were found within tunnels if the larval numbers were small and if food supplies were abundant. When the numbers were greater, the grass blades were reduced to short stubs and tunnel formation was no longer possible. In one field, defoliation was complete and the larvae began to feed on the heads of the timothy (Fig. 8). Fifth-instar larvae remained as such for three to nine days, the aver- age being six. The amount of feeding during this stadium increased to 19.68 per cent. The sixth and final stadium lasted from five to fourteen days with an average of nine. The amount of feeding during this stage increased to 68.88 per cent when 21 sq. cms. of blade surface were devoured. It is said that the larvae usually draw together bits of grass blades, stems and other debris to form a loose protective covering for the pupae. Such structures were common in many of the fields. In the Priceville area, however, large numbers of pupae were present and exposed on the surface of the soil. Many pupae were present on the underside of grass blades and the leaves of plants growing close to the ground, such as Echum vulgare L. (blueweed) and Verbascum thapsus L. (mullien) where as many as four pupae were found on a single small leaf. The pupal period lasted for an average of ten days but varied from six to eleven. When first formed the pupae were a green colour, similar to that of the larvae. Within a few days they became more of a yellowish- green. Progressive changes in the colour occurred throughout the pupal period that were indicative of its age. The green or yellow-green colour remained unchanged for five to six days. On the seventh day the eyes had a very faint tinge of pink that became more pronounced and within twelve hours was a deep red. During the next twelve hours (eighth day) the eyes changed to black and there was an orange colour evident in the wing pads. On the ninth or tenth day the wing pads darkened, the abdomen became a silvery-grey and the adults appeared in four to six hours. Adults : Under laboratory conditions the adults emerged between June 10 and June 30. Those emerging before June 18 were males and those after June 25 were females. The majority of both males and females appeared be- tween June 17 and June 22. In 1958 the first field-caught adults were taken on June 20, and in 1959 on June 16. The peak of adult activity was between July 3 and July 12. The life span appeared to be from three to four weeks. In 1957 adults were last seen on July 22, in 1958 on August 1 and in 1959 only the occa- sional specimen was seen as late as July 25. These specimens were much faded in colour and the wings were badly tattered. Mating was observed in the field and in the laboratory. On one occasion, pupae collected on June 27 were placed in a seal-tight cardboard carton and not examined until July 2. During this period the majority of adults had emerged and when the carton was opened, several pairs of adults were seen in copula. Mating had taken place soon after emergence and in total darkness. The flight of T. lineola differed somewhat from that of native species in that they were much slower and less alert. They were not as readily put to flight and hence easily caught. When at rest the wings were held in a manner peculiar to skippers. The forewings were held vertically over the thorax while the hind wings were held horizontally over the abdomen. Resting males and some females, when approached by other males, drew the forewing tightly together in the vertical position and vibrated the hind 193 wing very rapidly. The approaching male continued its flight without further investigation. : Oviposition was observed in the field and in the laboratory. The Ovipositing female alighted on the grass stem and moved around it until the tip of the abdomen came in contact with the overlapping edges of the blade sheath. The tip of the ovipositor was inserted under the edge of the sheath and the female moved slowly up the stem. The number of eggs found in any one oviposition site varied from 1 to 101, under laboratory conditions and from three to six in the field. Usually the eggs were laid touching one another and in many cases adhered sufficiently so as to form a single long chain. The same adhesive covering on the eggs held them to the leaf-sheath. There were several plants upon which the eggs were laid, at least under laboratory conditions. In 1958 adult skippers were placed in cages containing blueweed and either timothy, orchard grass or twitch grass. Eggs were found on timothy only. In 1959 the experiment was repeated and brome grass was used also, During these trials four non-viable eggs were found on the orchard grass. Seventy-nine eggs were found on the twitch grass and of these five were attached to the outside of the sheath. Of the latter, four were on the same stem about one inch above the node and were spaced one-eighth of an inch apart. The majority of those under the sheath were within 114 to 2 inches of the ligule. No eggs were found on the brome grass and, as in 1958, timothy was the preferred grass. Three hundred and seventy-four eggs were removed from timothy in 1958 and 151 in 1959. Under field conditions, eggs were found on timothy only. Other grasses may serve as oviposition sites but timothy appears to be the major one. The spread of this insect in Ontario has received little or no attention. A brief survey was made in 1958 to determine the limits of its spread. At that time it appeared to be present throughout the southern part of the province except for the Bruce peninsula and possibly the Windsor area. The north-easterly boundary appeared to be along a line from Midland, south around the west side of Lake Simcoe, east to Lindsay and south to Whitby. An intensive search in the area between Whity and Havelock failed to locate any specimens. Mr. A. P. Arthur’ reported the finding of larvae (possibly T. léneola) in the Belleville area in 1959. Mass movement of adults has been reported during their peak of abundance, This was mainly in a north-easterly direction and in general the skippers flew close to the ground and moved with the wind. Adults required nectar or water to maintain themselves. During the warmer part of the day they congregated in damp or wet spots. Depres- sions in roads and the edges of streams were common gathering sites and in Grey County several thousand adults could be seen at one time in such places (Fig. 1). Adults visited a wide variety of flowering plants. Thistle, blueweed, sweet clover, ox-eye daisy were among the more abundant plants and most widely used by the skippers. On a single thistle head as many as twenty-two adults were counted (Fig. 6). Parasites and Predators : The major emphasis of the 1958 programme was on the identification of species of parasites and the determination of their effectiveness. Of the 900 odd larvae collected and reared in 1957 not one was parasitized. In 1958 extensive collections were made of third-, fourth-, fifth- and 2Entomology Research Institute, Canada Department of Agriculture, Belleville, Ontario. 194 sixth-instar larvae. The different stages were segregated and reared separately to obtain parasites. The results are shown in Table I. In 1958, 488 pupae were collected and of these twenty-four were parasitized. Mr. A. P. Arthur collected 1711 pupae in 1959 and of these 133 were para- sitized. The majority of the parasites were Itoplectes conquisitor Say. Other parasites of the pupae were Pimpla pedalis Cress., Labrorychus sp. Larval parasites included Meteorus hyphantria Riley, Rogas sp., Horogenes sp. A species of Gelis was parasitic upon M. hyphantria and one Perilampid emerged from a pupa collected by Mr. Arthur. Several Tachinid parasites were reared from skipper larvae. TABLE I Numbers of parasites in the larvae of Thymelicus lineola (Ochs.) collected in 1958 May June Local Instat 223). 27 > 4 1A 1G 19 2a woe Lov Arkell Ath 53 5 58 Siclay a 67 100 he 14 256 6th i 229 249 A&85 Priceville 3rd 55 0 55 Ath oO DAL 791 Steet) aed 617 338 57 Ta L037 6th 0 49 828 638 .o'5)) (2330 Total 636 120 887 112 304 1166 2638 695 329 4512 # Parasites O70 0 0 4 2 3 2 2 ils % Parasitism O° 0 0 Oe O18 Sil 0:29: 0.617 0:29 The fields at Priceville had large numbers of damsel bugs Nabis subcoleoptratus (Kirby) but these were never observed to attack skipper larvae, nor could they be induced to do so when confined with them. A few birds were seen in these same fields but no feeding was observed. DISCUSSION It appears that this skipper has changed its habits somewhat since it was introduced into North America. In England it is said to be common in Kent and Essex marshes, and in scattered colonies elsewhere. Ford (2) stated that T. lineola although found inland was uncommon and very local away from the sea. In Ontario the species has become very abundant especially in the higher, inland areas around Orangeville, Listowel, and Durham. : The finding of the first adults in North America in the vicinity of a refuse dump suggests two things. Firstly, the means by which the introduction occurred and secondly, the stage in which it was introduced. The larvae need a-continuous supply of fresh grass for a period of about seven weeks in order to develop. The duration of the pupal period is about ten days and the adults are short-lived in the absence of water or nectar. Considering these facts it seems unlikely that the insect could have been introduced in any stage other than the egg. During this study the majority of the eggs were found on timothy. It is not known, however, if this is the major food plant in the coastal areas of Britain, but it seems likely that some other grass is involved. The use of various grasses as packing 195 material for fragile commercial products was not uncommon. It is sug- gested that the eggs of T. lineola were on one of the native European grasses used in packing and that these found their way to the refuse dump in London, Ontario. The introduction may have occurred in 1909 or a few years previous because within five years from when they were first collected, they were quite widespread and relatively abundant. Since its introduction into Ontario the skipper had moved westward into the Michigan area by 1927 but no reports have been made of it there since. As far as its movement within the province is concerned, it would seem that the roadsides and railway right-of-ways provide a suitable con- tinuum of suitable grasses for oviposition sites. ; In the heavy soil areas of Grey and Bruce Counties there is con- siderable timothy grown and here the skipper became very abundant. If the movement continues in the only direction it can go — to the north-east — the timothy-growing areas in eastern Ontario may soon be plagued by this pest. The parasites, so far associated with the larvae and pupae, cannot be effective in control because the skipper has but one generation a year. The parasites attacking the immature forms in June, emerge early in July and must find alternative hosts in which to maintain their numbers throughout the remainder of the summer. The chances of finding an alternative host in numbers comparable to those of T. lineola seem remote. In one field at Priceville, 1168 larvae were taken in 25 net-sweeps with a standard insect net. These were taken where the grass was short and only a percentage of the larvae present were collected. SUMMARY Thymelicus lineola (Ochs.) was introduced into Ontario about 1910 and since then has spread over most of southern Ontario except for the Bruce peninsula, It moved through much of the province without causing any concern. In the Moorefield, Durham, Priceville, Orangeville area it has done considerable damage to pasture and hay crops, especially to timothy. Other grasses such as twitch, orchard, meadow fescue serve as host plants. There is one generation per year. The larvae appear in early May and pass through six stadia during the following six weeks. The pupal period is of ten days or less, the adults emerging about July 1st. These remain active for three to four weeks and deposit their eggs on timothy and perhaps other grasses. The larvae develop inside the eggs within a 20-day period and pass the winter in this stage. Native parasites have been reared from larvae and pupae but those identified are multibrood species requiring other hosts. Other means of control have not been in- vestigated. Since the larvae live within tubes formed from the grass blades . they are protected from contact poisons. The use of potent residual com- pounds on hay and pastures grasses seems inadvisable. The use of bacterial disease organisms is being considered. LITERATURE CITED 1. Essic, E. O. (1947). College Entomology. Macmillan Company, New York, pp. 497-499. 2. Forp, E. G. (1947). (The New Naturalist) Butterflies. Collins, St. James Place, London. XIV, 368 pp. 48 colour plates, 24 black and white. : 3. HOLLAND, W. J. (1947) The Butterfly Book. Revised edition Doubleday and Company, Inc., Garden City, N.Y., 424 pp. 77 pl. 196 4, KuoTz, A. B. (1951). A Field Guide to the Butterflies of North Amer- ica, east of the Great Plains. Houghton Mifflin Co., Boston. The River- side Press, Cambridge, XVI, 349 pp. 40 plates. 5. MATTHEWMAN, W. G., HARCOURT, D. G., FRIEND, W. G., CAss, L. M., GUPPY, J. C., and BACKS, R. H., (1956). Insect conditions at Ottawa and Bradford. Canad. Insect Pest. Rev., 34 (1): 85-88. 6. RAWSON, G. W. (1931). The addition of a new skipper, Adopaea lineola (Ochs.), to the list of U.S. lepidoptera. N.Y. ent. Soc., 39 (4): 503-506. 7. SAUNDERS, W. E. (1916). European butterfly found at London, On- tacio. Ottawa Nat., 30: 116. 8. SKINNER, H., and WILLIAMS, R. C. (1923). On the male genitalia of the Hesperiidae of North America III. Trans. Amer. ent. Soc., 49: 129-155. 9. STONE, W. J. and STOVEN, G. H. T. (1950). The Caterpillars of British Butterflies. Frederick Warne and Co. Ltd., London and New York, 248 pp. 32 plates. 10. WARREN, L. O., and ROBERTS, J. E, (1956). A hesperiid Atalopodes campestris (Bdv.) as a pest of Bermuda blue grass pastures. Kansas emi soc., 29 (4) : 139-141. (Accepted for publication: March 2, 1961) FIELD EXPERIMENT ON THE USE OF A NEMATODE FOR THE CONTROL OF VEGETABLE CROP INSECTS H. E. WELCH and L. J. BRIAND? A neoaplectanid nematode, called DD136, and its associated bacterium are being tested at Belleville for their potentialities as both permanent and temporary biological control agents against specific insects in each of six selected niches. These are the root, the tightly leafed herb, the loosely leafed herb, the cereal, the tree, and the aquatic environment. Data from the tests in these environments will permit prediction of the value of the nematode against insect pests of similar or related niches. Trials of the nematode against the Colorado potato beetle, Leptinotarsa decemlineata (Say), a pest of a loosely leafed herb, were reported elsewhere (2). Tests against the cabbage root maggot, Hylemya brassicae (Bouché), a pest of a root crop, the European corn borer, Pyrausta nubilalis (Hbn.), a pest of a cereal, and the imported cabbage worm, Pieris rapae (L.), a pest of a tightly leafed herb are reported here. The nematode, first isolated by Dutky and Hough (1) from codling moth larvae, is ingested with food by a host, enters the haemocoele, and releases the bacterium. The bacterium multiplies rapidly, and kills the host. The nematode feeds on the tissue of the dead host, passes through i—=ntomology Research Institute for Biological Control, Research Branch, Canada Department of Agriculture, Belleville, Ontario. Proc. ent. Soc. Ont. 91 (1960) 1961 OG several generations, and eventually emerges in massive numbers as in- fective larvae transporting the bacterium and ready to infect other hosts. Many insects can be infected in the laboratory. Large numbers of the nematodes may be reared in larvae of the greater wax moth, Galleria mellonella (L.), stored in water at 45°F. with little loss of vitality for a month or more, and thus accumulated in sufficient numbers for extensive field trials. All field experiments were made during the summers of 1958-60 at the Institute Field Station, located at Chatterton, ten miles north of Belle- ville, Ontario. Most experiments were of the latin square design. Mr. Allan Dempsey, the Institute’s horticulturist, was Po penee le for the planting and cultivation of the crops. THE CABBAGE ROOT MAGGOT In the laboratory tests nematodes were inoculated onto thin slices of rutabagas on which a specific number of maggots were placed. These trials were made in closed glass dishes at high humidities and at temper- atures of 45 to 75°F. Mortality of all instars was in excess of 60 to 70 per cent at applied dosages of 370 to 640 nematodes per dish. Infected maggots become less active, stop feeding, and die within four days at 65°F. Their cadavers are a light brown colour at first, then become darker, but remain whole and unputrified for some time. Field trials on cabbages, radishes, and rutabagas, compared the amount of maggot damage on untreated to that on nematode- and insecti- cide-treated plants. Two comparisons of nematode applications were made in the trials: the effectiveness of several light treatments versus a single heavy treatment of equal numbers, and that of applying nematodes in water, or in wax moth cadavers buried near the roots of the plant. The last method was based on the observation that the nematodes emerge slowly from the cadaver and thus would provide a continual source of nematode material, Nematode dosage ranged from 1.0 x 10° to 5.1 x 10° per plant. Indirect measurements of the effect of the treatments on the pest insect population were made by recording the relative amount of damage to the plants. The roots of each plant were examined and the amount of engraving and tunnelling classified as light, medium, or heavy. Table I records the per cent of the plants that were damaged for each treatment in the five trials. It is obvious that in all trials at maggot densities of 1.0 to 4.9 maggots per plant, the nematode treatments resulted in a decrease in plant damage compared to untreated plants, but that the reduction was not as great as in those treated with insecticide. There was little difference between the single or serial application of nematodes, or between water application and cadaver burial. Just as a reduction occurred in the percentage of damaged plants treated with nematodes, so there was a reduction in the degree of damaged or infested plants. For example, in the cabbage trials of 1958, the untreated plots had seven per cent of the cabbage roots heavily damaged, 18 per cent with medium damage, and 54 per cent with light damage, while there were no heavily damaged roots in the nematode-treated plots, only three per cent with medium, and 49 per cent with light damage. Limited data are available on nematode survival in the soil. Soil samples taken from around the roots of plants two weeks after treatment were found to contain infective larvae. The similarity of results between single and several applications suggests that the nematodes in the single 198 TABLE [| Per cent of plants damaged in trials of the nematode, DD136, against the cabbage root maggot, Chatterton, 1958-60 Treatments Trial data Untreated Nematode Serial Insecticide Cabbages 1958 80 54 54 8 1.7 maggots per plant 5.1 x 10° nematodes per plant Rutabagas 1958 Fal. 58 63 AO 2.5 maggots per plant 3.3 x 10° nematodes per plant Rutabagas 1959 TEL 65 61 44 2.5 maggots per plant 4.5 x 10° nematodes per plant Cadavers Cabbages 1960 50 18 Padi 0 1.0 maggots per plant 1.5 x 10° nematodes per plant Rutabagas 1960 96 90 96 94 4.9 maggots per plant 1.0 x 10° nematodes per plant _ treatments must survive at least a month to produce the same control as the multiple applications. Trials are also underway to verify in the Belleville region Dutky’s observation that the nematodes will overwinter in the soil. EUROPEAN CORN BORER Tests against the corn borer were made in the field in 1960 following successful infection of the borers in the laboratory. The field trials con- sisted of three replicates of a check, nematode treatment, and insecticide treatment (5% granular DDT). Two inoculations, each of approximately 5,000 nematodes each, were made into the leaf sheath surrounding the growing tip of the plant just prior to tassel formation when the plants were 3-4 feet high. Plant infection was determined by counting the fallen tassels, and cob infection ascertained by removing all of the cobs and recording the presence of the corn borer or its damage. Five days after the first application six dead corn borer larvae were recovered from plants in the field. As dissection revealed that the borers were killed by the nematode and bacteria, field infection was thus established. Analysis of variance showed that the differences in the number of plants and cobs infected by corn borers for the various treatments were significant (P<0.01). A comparison of fallen tassel counts for untreated and nematode-treated plants revealed no significant difference, but com- parison of cob damage in untreated and nematode-treated revealed sig- nificant differences (P<0.01). The percentage infections were as follows: untreated plot, 44.2 per cent of the plants and 34.2 per cent of the cobs; nematode-treated, 32.8 per cent of the plants and 26.3 per cent of the cobs; 199 insecticide-treated, 18.2 per cent of the plants and 5.4 per cent of the cobs. The control produced by nematode treatment did not approach that of insecticide, but is encouraging, particularly in view of the late application of a relatively low dosage. IMPORTED CABBAGE WORM Laboratory tests revealed that the caterpillars of the imported cabbage worm, and cabbage looper, Trichoplusia ni Hbn., were readily infected at temperatures of 60 to 90°F. Field trials, mainly against the imported cabbage worm, the com- monest of the three cabbage pests in the Belleville area, consisted of four replicates of the following four treatments: a check in which water was added to the heads; inoculation by automatic pipette of two doses of nematodes in water, the first of approximately 3.4 x 10° nematodes and the second of 1.5 x 10° nematodes per plant; implantation of infected wax moth cadavers into the heads; and rotenone dusting. Two successive samples, a week apart, were taken after each treatment to determine the kill of the caterpillars. A sample involved the cutting of a row of cabbages, removal of larvae, and the recording of living and dead individuals. Many of the dead larvae were infected with nematodes. TABLE II Per cent mortality of imported cabbage worms in trials with the nematode, DD136, at Chatterton, 1960 Treatments Date Untreated Nematode Cadaver Insecticide August 16 First treatment August 25 Dre tno 27 15 89 September 1 0.0 18 one 19 September 6 Second treatment September 12 123 73 9.2 84 September 22 4.0 (ws 26 82 Table II shows that the nematodes were more efficient with the ad- vance of the season, and that in mid-September they killed almost as many larvae as the insecticide. It is also obvious that nematodes inoculated in water produced a better kill than did implantation of the cadavers, prob- ably because the inoculated nematodes are better distributed in the cab- bage head. The increase in nematode efficiency following the second application is probably related to the tighter form of the cabbage head and the greater retention of moisture ensuring better nematode survival. The first sample was taken when the cabbages commenced to ball; the second, after ball formation; the third when the cabbage heads were immature; the fourth when the cabbages were ready to harvest. These mortality data are encouraging, but another aspect of the problem must be mentioned. The mean number of caterpillars per cabbage head is given in Table III. A general increase in the mean number with time occurs as one would expect. The most interesting feature is the low 200 TABLE III Mean number of imported cabbage worms per cabbage plant in treatments at Chatterton, Ontario, 1960 Treatments Date Untreated Nematode Cadaver Insecticide August 25-26 4.2 2.9 4.9 tet September 1 fhe, 8.6 TA ies September 12-13 AE, TAS) PAL 3.9 September 22-23 12 28 1 6.7 number of caterpillars in the insecticide-treated plants, compared to the high numbers in the nematode-treated and untreated plants. The effect of the insecticide in immediate killing of freshly hatched caterpillar larvae, and the difficulty of finding these cadavers probably explains the lower means on the insecticide-treated plots. The lower means shown in the last sample for the untreated cabbages and those treated with wax moth cadavers probably resulted from the pupation of the caterpillars, while the increase in the means for both nematode and insecticide treatment represents the accumulation of cadavers of the cabbage worm. Nematode infection is related to caterpillar size; the larger the cater- pillar, the more leaf consumed, and the greater the chance of infection. Unfortunately leaf consumption is leaf damage, so that a rather paradoxi- cal situation occurred in which nematodes killed caterpillars at rates equal to insecticide treatment, but failed to reduce cabbage damage. This was also observed in 1958 where nematode-treated cabbages had more leaf damage and a lower mean weight than the insecticide-treated cabbages, and leaf damage and mean weight similar to that of untreated cabbages. DISCUSSION Environmental moisture was a limiting factor in the utilization of the nematode against the potato beetle (2), but was not a factor in their use against these pests. Soil moisture is sufficient for nematodes in the root environment; moisture is abundant in the leaf axils of corn, and is conserved by the tall and rapid growth of corn that soon stabilizes its own microclimate in a plot or field; moisture in the head of cabbages is suffici- ent, at least in later stages of growth, even though the head is frequently exposed to high temperatures in the field. Another series of problems must be examined for an adequate ap- praisal of the potentialities of the nematode. Is there a mechanism for the nematode to maintain itself in the insect’s environment, one year to another, and so increase the natural regulating factors operating against the pest population, or must the treatments be repeated annually and the nematode used as a biotic insecticide? While our investigations are in- complete, we can reach at least one or two tentative conclusions, The soil of the root niche provides protection for the nematode colony, and thus permits infection of insects in crops of succeeding years, par- ticularly where root crops are grown extensively. Future work will determine whether the nematode can maintain itself in the soil for long periods of time and the numbers that will be necessary for root protection. 201 Nematode survival from one year to another in the corn plant will be hindered by the destruction or removal of stalks for silage. The nematode, however, appears promising as a biotic insecticide because of its ability to move about in the stalk of the plant and so reach sites of corn borer infection. - The nematode would seem to have no potentiality as a biological con- trol agent against the imported cabbage worm, as no possible method exists for its infection of caterpillars in succeeding crops. Its value as a biotic insecticide seems doubtful on the basis of the data presented herein, but it is possible that, at higher dosages, more caterpillars would be killed resulting in less damage. The nematodes and insecticides killed similar percentages of insects, the differences in damage arising from the lower caterpillar density on the chemically treated plants, a fact probably attributable to the kill of the freshly hatched larvae by the insecticide. Further investigations should determine whether more treatments at higher dosages of nematodes will be more effective in the control of damage. LITERATURE CITED (1) Dutky,S. R. and HouGH, W.S. (1955). Note on a parasitic nematode from codling moth larvae, Carpocapsa pomonella (Lepidoptera, Ole- threutidae). Proc. ent. Soc. Wash. 57: 244. (2) WELCH, H. E. and BRIAND, L. J. (1961). Utilization of a nematode and its associated bacterium for the control of the Colorado potato beetle. Canad. Ent. In press. (Accepted for publication: February 4, 1961) 2()2 PRESENT STATUS OF THE SAWFLY FAMILY DIPRIONIDAE (HYMENOPTERA) IN ONTARIO’ C. EH. ATWooD The family Diprionidae is a well-defined group of insects whose food plants are all members of the order Coniferales, chiefly the family Pinaceae. Although some species are found in warm regions, such as Algeria, Cuba and the southern United States, the group appears to thrive best in cooler regions, and the pine forests of Eurasia and North America display the richest fauna. The total world fauna is apparently less than 75 species; in Ontario 16 species are found, four of which have been in- troduced from Europe in modern times. While the family as a whole must be considered harmful, none of the species cause outbreaks as spectacular as those of the forest tent caterpillar (Malacosoma disstria Hbn.), the spruce budworm (Choristoneura fumi- ferana [Clem.]). or the larch sawfly (Pristiphora erichsonu [Htg.]). The most destructive species in Canada so far has been the introduced Euro- pean spruce sawfly Diprion hercyniae (Htg.), which killed millions of cords of spruce in the Gaspé peninsula of Quebec, but has done no damage in Ontario. Their chief economic importance in this province is as pests of Christmas trees, plantations, roadside plantings and ornamentals. This review is based on a survey of available current literature, to- gether with a few notes from the work of my students and myself. It will contain little that is new to the sawfly specialist, but should help to orientate the general entomologist and the general zoologist. The first descriptions of American Diprionidae were published in the early 1800’s, and, in general, interest in these insects has increased with the development of forestry. This interest was chiefly economic, but re- cent investigations have shown that some phases of evolution and genetics are well illustrated by the family and that studies of their be- haviour and ecology are of considerable theoretical value. The literature is in general in rather bad shape, a result achieved by premature publica- tion and careless preparation of manuscript. Many of the earlier host records are unreliable; for example, the author’s statement that Neodt- prion abietis (Harr.) damages Pinus banksiana Lamb., (2), was based on a report which he has been unable to verify and which probably concerned N. nanulus nanulus Schedl.; similarly, reports of N. pinetum (Norton) feeding upon any host other than Pinus strobus L. are probably based upon misidentification or upon partly grown larvae which have migrated from some other pine upon which the eggs are laid. The student of the literature on Diprionidae must therefore be on his guard against unverified statements, misspelled words, careless use of names and other pitfalls with which this group seems to be particularly afflicted! GENERAL OUTLINE OF LIFE HISTORY The Ontario Diprionidae have a fairly uniform type of life history with a few major patterns. All lay their eggs in living foliage of conifers in pockets gouged out by the saw-like “lancets’” of the females. One group lays the eggs in late summer or fall; data secured in the author’s labor- atory, (Brygider, 13), show that at least three of these species start development at once and progress to distinctly segmented embryos, at iContribution from the Department of Zoology, University of Toronto, Toronto, Ontario, prepared at the invitation of the Publications Committee, Entomological Society of Ontario. Proc. ent. Soc. Ont. 91 (1960) 1961 205 which stage development stops until next spring. The other group lays the eggs in spring or early summer; larval development is completed, and cocoons spun by fall and the winter is passed in the cocoon. Again one group, including most Ontario forms, has but one generation per year, but a second group. has a partial second generation; the percentage partici- pating in this second generation is not well known for Ontario conditions. All species as far as known are facultatively parthenogenetic with the exception of D. hercyniae (Htg.) (4). Within this general framework each species shows characteristic variations in physiology, behaviour and ecological relationships, most of which are not yet known in detail. Some species confine themselves almost exclusively to one speices of tree, others to the “‘hard” pines, while some will attack both “hard” and “soft”? pines; even on the same tree some species complete larval development faster than others (author’s data) ; some persist at fairly high levels in a given area for many years while others cause heavy defoliation for a year or two and then abruptly dis- appear; some are very rare in Ontario. Reasons for these phenomena are not well known. Investigations of larval and adult behaviour of Ontario species have been carried out chiefly by Ghent (18-24); Green (26-27); Griffiths (28-32) ; Schedl (46) ; Wellington et al (48), and by the author. Ghent’s analysis of the gregarious or subsocial feeding behaviour of larvae is of particular interest (18; 24). Morphology of adults has been studied by Reeks (42) and Ross (44) among others, and larval anatomy by Maxwell, (37), Wallace (47), and Yuasa (51). SYSTEMATICS The present classification of this group is: Order: Hymenoptera. Suborder: Symphyta. Super family: Tenthredinoidea. Family: Diprionidae. The Symphyta includes all the more primitive Hymenoptera, which may be recognized by the broadly sessile abdomen and by the partial amal- gamation between the first abdominal segment and the thorax. The ovipositor of the female is adapted for boring or sawing ; the larvae have a well-developed head with never more than one pair of ocelli and 13 trunk segments; three pairs of thoracic legs and frequently six or more pairs of abdominal appendages are present. Among the families of the sub-order the Diprionidae may be identified by the serrate (female) or pectinate (male) antennae; and the absence of sterno-pleural sutures and preapical spurs in adults (Ross, 44), while the larvae may be separated from those of the common Tenthredinidae or Pamphyliidae found on conifers by the presence of eight pairs of abdominal prolegs on segments two to eight and ten. In most species the larvae are gregarious at least when young but do not form shelters of any kind. Reeks (42, p. 263), has ascribed plumose antennae to Diprion, and Green (27, p. 371), describes the antennae of Neodiprion lecontet (Fitch) as filiform. Both these statements are based on faulty observation, The identification of the Ontario species of the family presents in some cases great difficulty. Both adults and larvae are variable, and the variations often overlap. Atwood and Peck pointed out in 1943 (8), that if adult characters, larval characters, methods of oviposition, food plant 206 and life histories were known, it was possible to delimit biological units which could be identified; the proper labels to apply to these units would then have to be determined by comparison with types, study of descriptions, etc. Their concept of biological units represented in Ontario still appears to be the closest approach to reality. Parts of the scheme have been rejected by the Division of Forest Biology and by Ross (in Muesebeck et al, 39), but have been re-accepted again by Ross (in Krombien et el, 36), with some of the units designated as “‘sub-species’’, others as “‘complexes’’. The meaning and reality of these terms as applied to the Diprionidae have yet to be completely investigated. Fig. 1. Some characteristics of the family Diprionidae: A. Larva; B. Adult female; C. Antenna of female; D. Antenna of male; E. Egg pockets in jack pine needle. A key for the identification of the species is beyond the scope of this paper, but if that of Atwood and Peck (3), and of Ross (45), are used in connection with the annotated list below, it should be possible to secure identification of most forms encountered. The U.S.D.A. Synoptic Catalog of Hymenoptera (Muesebeck et al, 39), is quite unreliable for Neodiprion, 207 ‘ and the supplement (Krombein et al, 36), should be followed until further work supplies a more authoritative check list. A new approach which may help to clarify the situation is that of West et el (49) who have pioneered in the use of serological and chromatographic techniques with this group. ANNOTATED LIST OF ONTARIO DIPRIONIDAE Genus Monoctenus. M. juniperinus MacG. is probably the best name to apply to the diprionid commonly found in eastern white cedar (Thuja occidentalis L.) and also occurring on red cedar (Juniperus virginiana L.). It is widely distributed and in some years quite abundant but never of economic im- portance. It spends the winter in the cocoon. Genus Neodiprion. N. abbotu (Leach). Very rare in Ontario and western Quebec. Recorded in the field from red pine (Pinus resinosa Ait), may occur on jack pine. Winters in cocoon. N. abietis (Harris). There seems little doubt iat the common eastern form on spruce and balsam fir is the species which Harris saw in 1841 and named abietis. It causes heavy defoliation of balsam fir (Abies balsamea [L.] Mill) in open stands, along shore lines, in pastures, etc., but in Ontario does not damage spruce (Picea spp.) to the same extent. Certain areas, such as the Ottawa valley from North Bay to Ottawa and the shores of Lakes Huron and Superior in the Blind River — Batchawana section along Highway 17 seem to be favourable for this species, and several peaks of abundance have occurred there on balsam fir since 1937. It spends the winter in the egg stage in needles. N. compar (Leach) This species is widely distributed on red and jack pine but is never abundant, The larvae are less gregarious than most species and are seldom found in groups of more than four or five. Winters in cocoon. N. leconter (Fitch) This is the well-known sawfly attacking red pine in plantations and ornamental plantings throughout central and southern Ontario. In On- tario I have observed oviposition on red pine, jack pine and Scots pine (P. sylvestris L.), and in the United States many other species of pine serve as oviposition sites. West (49), has suggested that in one infestation which he saw, eggs had been laid on white pine (P. strobus L.), but he found no egg scars, and his opinion is based on evidence which fails to carry conviction. In the author’s laboratory we have for years tried to induce N. lecontei to lay eggs on white pine but have failed 100 per cent. Also Griffiths (29), found no eggs on white pine during extensive observa- tion. We have established, however, that if young larvae are placed on white pine immediately after hatching from eggs laid on red pine, they can successfuly complete development into the adult stage. (McGonigal and Atwood, unpublished data). N. lecontet normally has one generation per year in Ontario, more in the southern parts of its range. We have some evidence of two genera- tions in two areas in southern Ontario but have been unable to prove this 208 point. Infestations by this species may be very serious since the progeny of a single female laying 100 eggs or more may completely defoliate and kill a young pine in a single year. Plantations of red pine such as the Kirkwood Plantation near Thessalon have in the past suffered mortality which ran to thousands and even hundreds of thousands of trees. Out- breaks often end abrutly from a variety of causes, including disease. N. lecontet winters in the cocoon. N. maurus Rohwer The larvae of this species closely resemble those of the spotted type of N. pratti banksianae Roh.; Ross confused it with this insect in the 1951 check list under the name N. americanus, and it has been misidentified in other collections, Consideration of the life history and the other points noted in Atwood and Peck (3), and reference to Ross (45), should keep the record straight. It is a rare species in Ontario; the larvae occur in (generally) small colonies on jack pine, and the winter is passed in the cocoon. N. nanulus nanulus Schedl. This sawfly is common on red and jack pine in southern and central Ontario, and on jack pine it extends into the northern and western areas. Outbreaks causing heavy defoliation of jack pine have occurred in the Biscotasing and Hawk Lake areas; at Kipawa Lake, just outside the eastern boundary of Ontario, feeding on mature red pines has been heavy enough to cause noticeable thinness of the crowns. No actual mortality of trees has occurred to my knowledge, but growth of young pines may be affected by heavy defoliation (Kapler and Benjamin, 35). This sawfly passes the winter in the egg; the cocoons are often found on the trees and on bits of bark, chips, etc., lying on the ground; many, however, are spun in litter and duff. N. nigroscutum Midd. This species was originally found by Dr. Schedl and recognized as distinct; what seems to be the larva was also found by the author and appears in Atwood and Peck (3), as Neodiprion sp. (p. 134) ; at that time reared females were not available for comparison with the type material of nigroscutum Midd. Since then more reared adults have become available; ‘more data have accumulated, and Ross in his 1955 paper again recognized it as a species. The larva is dull greenish with darker stripes and a black head; eggs are closely spaced on jack pine; the winter is spent in the cocoon. Probably the rarest of Ontario Diprionidae and more data is needed to thoroughly establish its status. N. pinetum (Norton) This sawfly is not very common in Ontario although small patches of defoliation are sometimes reported. I have been unable to find it in the field on any tree other than white pine. The larvae are very pale yellow, with black heads and with a body pattern which is closer to that of N. lecontet than of any other species. The winter is passed in the cocoon. N. pratti banksianae Rohwer. This is one of our most common Diprionidae, reported from jack pine in most cases but sometimes laying eggs on red and Scots pine. (Author’s data). In the laboratory we have successfully reared larvae on white pine but have never found eggs on this species in field or laboratory. 209 Outbreaks of this species may hasten the death of overmature jack pine and have sometimes killed a few younger trees, as in a plantation near Spencerville in the 1940’s and more recently near French River. Generally trees survive even prolonged attack. Infestations of this species seem to persist at a fairly heavy level for a number of years; some of my collecting spots have had large numbers of larvae for ten years or so. The name of this insect has been changed several times, and its present status as a subspecies of N. pratt: (Dyar) needs to be confirmed by research. The winter is. spent in the egg stage. N. sertifer (Geoffroy) This is the only Neodiprion native to Europe: it became accidentally established in the United States and from there spread to Ontario where it is found as far north as Lake Simcoe and Bruce county. The most common host tree is Scots pine, but many other two-needled pines have been attacked. In the author’s laboratory it has been successfully reared on white pine, (Rose, 43). In Ontario this insect is chiefly of importance as a pest of Christmas trees which may become unmarketable as a result of heavy defoliation. Its continued spread toward the north may result in damage to plantations of other sorts of trees. Eggs remain in the needles of pines through the winter. N. swainet Middleton. From the economic point. of view, this is probably the most dangerous species of diprionid in eastern Canada with the exception of the European spruce sawfly. A number of outbreaks have occurred on jack pine in Ontario and Quebec; on the sample plots in jack pine of commercial size on Kipawa Lake, mortality reached 85%, while practically all the mature trees over many square miles were ‘“‘stag-headed” for years afterward. In the field this species appears to lay eggs only on jack pine, but partly grown larvae can complete development on red pine, (author’s data). The eggs are laid in such a way that many of them appear as pairs in the two needles of a fascicle; as many as four such pairs per fascicle occur in some of my collections. The egg-laying habits of the female, which result in this spacing of eggs, have been described by Ghent and Wallace (22). N. swainet spends the winter in the cocoon. N. rugifrons Midd. The status of this name is very confused. Dr. Schedl made the original Ontario collections near Biscotasing, and from this material he and Middleton named two species (N. rugifrons Midd. and N. dubiosus Schedl). However, in 1918 Rohwer had proposed two names for material collected in the United States, viz. N. virginiana and N. affims. In 1951 Ross synonymized all these under the name N. virginiana; in the 1955 paper the term virgimanus complex is proposed to cover this, but in the same paper virginicus is in some places substituted for virginianus! For the present I use N. rugifrons Midd. for Ontario material but without much conviction. All the biological evidence I have to date indicates that we have in Ontario one rather variable species whose host is almost exclusively jack pine, whose larvae have theads ranging from orange to black and which passes the winter in the cocoon. More data is clearly needed to settle the question of nomenclature. In Ontario and western Quebec this species is widely distributed and often causes small, heavy but generally short-lived infestations on isolated trees or groups of trees, plantings along highways, etc. In the late 1930’s 210 it was common but not abundant on the crowns of mature pulpwood size jack pine in the Kipawa basin, and in 1957 and 1958 mature open grown jack pines some 30 feet in height were heavily defoliated near Maynooth, Ontario; in general, however, the heaviest defoliation occurs on younger, smaller trees. Genus Diprion D. (Diprion) similis (Hartig.). This speices, which is native to Europe, is now found in much of central Ontario and appears to be spreading although it is nowhere abundant. It attacks many European species of pine but in this area is most common on white pine to which it is a potential threat. In Wisconsin white pines of timber size have been heavily defoliated. It has two generations per year, the winter being passed in the cocoon. Many cocoons are spun above the ground level on trees, and this habit may make it susceptible to parasites, predators and climatic factors. D. (Gilpinia) frutetorum Fabricus. This species is widespread, but not abundant, in southern Ontario on Scots and red pine. The original infestation was found by D. E. Gray near Niagara Falls, Ontario, in 1934 (25). From our data it appears to have a partial second generation in the. Toronto area but no detailed in- formation is available. The insect remains in the cocoon during the winter. D. (Gilpinia) hercyniae (Hartig.). This is the famous “European spruce sawfly’’ which caused so much excitement and alarm when it was first discovered in Canada. It was originally thought to be D. polytomum (Htg.) but is now known to be specifically distinct (Balch, Reeks and Smith, 4). Picea spp. are the only known food plants. Males are extremely rare, and the unfertilized eggs hatch into females. In the northern part of its range, e.g. Gaspé peninsula, it has one generation per year; from Lake Temiskaming southward at feast a portion of the population go through two generations a year (Atwood, 1, and unpublished data from this laboratory). In 1950 the author found this species in Quetico Park, and at about the same time a Forest Insect Survey ranger found it near Fort Frances so that its range now goes right across the province with the possible exception of the area north of Lake Superior. Larvae may remain in cocoons for as much as seven years in Gaspé; in Ontario it is only known that the total late summer population passes the winter in the cocoon. CONTROL MEASURES The Diprionidae are attacked by numerous insect parasites, some of which are restricted to this family while others are more general in their host selection (Findlayson, 17; Findlayson and Findlayson, 16; Raizenne, 41). A number have been introduced from Europe, chiefly in an effort to control D. hercyniae; of these Dahlbominus fuscipennis (Zett.) is now known to be established as far west as Poynette, Wis., (Kapler and Ben- jamin, 35), and may be widely distributed in Ontario. The most spectacular control agency which has appeared under natural conditions is the virus which began to attack D. hercyniae in 1936 and in 1940 and 1941 was causing mortality ranging from 94.3 to 100 per cent on various plots in New Brunswick, (5). Mortality ranging from 90 to over 94 per cent was also produced in N. sertifer populations by spray- ing infested plantations with virus suspensions, (10). 211 Detailed figures for parasitism under natural field conditions are not available for many species. Some data of this sort are provided by Schedl (46), and Griffiths (30) found that over a period of three years parasit- ism of N. sertifer ranged from 8.1 to 29.1 per cent of sound cocoons, while in another study the same author (32), found 9.1 to 29.9 per cent of the feeding larvae of N. p. banksianae to be parasitized. No egg parasitism was recorded for N. sertifer while 0, 3.8 and 1.3 per cent egg parasitism was present in three successive years in N. p. banksianae. In comparison with this, parasitism of N. n. nanulus in Wisconsin ranged from 6.86 to 52.22 per cent of cocooned sawflies during three years (Kapler and Benjamin, 35). Griffiths (28), found variable but generally higher eggs parasitism on N. lecontet; in 1955 at the Kirkwood plantation it ranged from 0 to 87 per cent in different egg clusters and from 13 to 58 per cent in different plots. Diseases are important natural controls but are very spore among native species. The outbreak of D. hercyniae in Gaspé and New Brunswick was ended by a virus disease (Balch and Bird, 5). It was found that this disease could be artificially disseminated, and later a virus of N. sertifer was manipulated in the same way (Bird, T- 12). Predation by small mammals such as mice, shrews, chipmunks and squirrels is one of the important natural control factors, often the most effective (Holling, 34; Kapler and Benjamin, 35; Morris, 38). Birds do not appear to be of major importance in general although Sched! recorded heavy predation during his studies. Many arthropods such as spiders, Pentatomidae, coccinellid larvae, (author’s observation) are known to attack larvae, and doubtless adults are also caught by predacious insects such as Reduviidae, which Pointing (40), records as predators of Pikonema adults. Little can be said about forest management as a method for preventing damage by diprionids. Presumably vigorous mixed stands are desirable as a defence against N. swainei and N. p. banksianae, which have killed chiefly mature, over-mature or unthrifty jack pine but on the other hand, N. lecontei, and to some extent N. rugifrons, prefers younger trees. No experimental data seem to be available; Griffiths (29), and Benjamin (65), record conflicting observations of the preference of N. leconter for open-grown versus shaded trees. Where ornamentals or plantations are involved, chemical control may be justified. The Diprionid larvae are very susceptible to DDT, especially in the younger stages, and if the expense is justified, immediate control may be effected. Publication 1002 of the Canada Department of Agricul- ture lists the following directions for control of N. lecontei, and this treat- ment should be equally effective for any species if applied at the right time in the life cycle. 25% WDE Emulsible Method of Application Concentrate Water (1) Hand or Pack Sprayer (2.5% DDT spray) 1 part 9 parts Spray must saturate the insect colonies (2) Mist sprayer (10% DDT spray) 2. parts 3 parts Apply at rate of 5 gallons per acre _ (38) Power sprayer (0.25% DDT spray) 1 part 99 parts Apply at rate of 100 gallons per acre 212 The species which may require this treatment are: N. abietis, N. _lecontei, N. n. nanulus, N. p. banksianae, N. sertifer, N. swainei, N. rugifrons, D. similis, D. hercyniae. REFERENCES CITED (1) ATwoop, C. E. (19387). The European spruce sawfly situation in (2) (3) (4) (9) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) western Quebec and Ontario. Rep. ent. Soc. Ont. 68: 48-50. ATWOOD, C. E. (1988). 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On the artificial dissemination of the virus disease of the European sawfly Neodiprion sertifer (Geoff.). Can. Dept. Agr. For. Biol. Div. Bi-mon. Prog. Rept. 8(3). BIRD, F. T. (1952). On the multiplication of an insect virus. Biochim. Biophys. Acta 8: 360-368. BIRD, F. T. (1953). The use of a virus disease in the biological control of the European pine sawfly Neodiprion sertifer (Geoff.). Canad. Ent. 85: 437-446, BirD, F. T. (1954). The use of virus diseases against sawflies. Rept. Sixth Commonwealth Ent. Conf. London. BirD, F. T. (1955). Virus diseases of sawflies. Canad. Ent. 87: 124-127. : BRYGIDER, W. (1952). In what embryonic stage do the eggs of Neodiprion enter the winter diapause? Canad, J. Zool. 30: 99-108. BUCKNER, C. H. (1955). Small mammals as prediators of sawflies. Canad hmb. S73 121-123) FINDLAYSON, L. R. and FINDLAYSON, T. (1958). Parasitism of the European pine sawfly Neodiprion sertifer (Geoff.) (Hym., Diprion- idae) in southwestern Ontario. Canad. Ent. 90: 223-225. FINDLAYSON, L. R. and FINDLAYSON, T. (1958). Notes on parasites of Diprionidae in Europe and Japan and their establishment in Canada on Diprion hercyniae. Canad. Ent. 90: 557-563. FINDLAYSON, T. (1960). Taxonomy of cocoons and puparia, and their contents, of Canadian parasites of Diprion hercyniae (Htg.) (Hym., Diprionidae). Canad. Ent. 92: 922-941. GHENT, A. W. (1954). An investigation of the feeding behaviour of the jack pine sawfly Neodiprion banksianae Roh. M.A. Thesis, Uni- versity of Toronto. 213 (19) (20) (21) (22) (23) (24) (25) (26) (27) (28) (29) (30) (31) (32) (33) (34) (35) (36) (37) (38) GHENT, A. W. (1955). Light reactions of newly hatched larvae of the jack pine sawfly Neodiprion americanus banksianae Roh. Can. Dept. Agr. For. Biol. Div. Bi-mon. Rept. 11 (2). GHENT, A. W. (1955). Oviposition behaviour of the jack pine sawfly Neodiprion americanus banksianae Roh. as indicated by an analysis of egg clusters. Canad. Ent. 87: 229-238. GHENT, A. W. (1958). 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(1956). Parasitism of the eggs of Neodiprion lecontei. Can. Dept. Agric. Div. For. Biol. Bi-mon. Prog. Rept. 12(4). GRIFFITHS, K. J. (1958). Host tree preferences of Neodiprion lecontet (Fitch). Can. Dept. Agr. Div. For. Biol. Bi-mon. Prog. Rept. 14 (5). GRIFFITHS, K. J. (1959). Observations on the European pine sawfly N. sertifer (Geoff.) and its parasites in southern Ontario. Canad. Ent. 97: 501-512. GRIFFITHS, K. J. (1960). Oviposition of the red-headed pine sawfly - Neodiprion lecontet (Fitch). Canad. Ent. 92: 430-435. GRIFFITHS, K. J. (1960). Parasites of Neodiprion pratti banksianae Rohwer in northern Ontario, Canad. Ent. 92: 653-659. HARRIS, T. W. (1841). Report on insects of Massachusetts injurious to vegetation. p. 376. Cambridge. HOLLING, C. S. (1955). The selection by certain small mammals of dead, parasitized and healthy prepupae of the European pine sawfly, Neodiprion sertifer (Geoff.). Canad. J. Zool. 33: 404-419. KAPLER, J. E. and BENJAMIN, D. M. (1960). The biology and ecology of the red pine sawfly in Wisconsin. For. Sci. 6: 253-268. KROMBEIN, K. V. (1958). Hymenoptera of America north of Mexico Synoptic Catalog. U.S.D.A. Agr. Monog. No. 2. first suppleme pp. 9-11. MAXWELL, D. E. (1955). The comparative larval maton of saw- flies. Canad. Ent. 87: (Suppl.) : 1-132. Morris, R. F. (1942). Preliminary notes on the natural control of the European spruce sawfly by small mammals. Canad. Ent. 74: 197-202. 214 (39) MUESEBECK, C. F. W., KROMBEIN, Karl V., TOWNES, Henry K. et al (1951). Hymenoptera of America North ‘of Mexico — a Synoptic Catalog. U.S.D.A. Agr. Monog. 2: 18-21. (40) POINTING, P. J. (1957). Studies on the comparative ecology of two sawflies, Pikonema alaskensis Roh. and Pikeonema dimmocku Cress. (Tenthredinidae, Hymenoptera). Ph.D. thesis, University of Toronto. ronto. (41) RAIZENNE, H. (1957). Horest sawflies of southern Ontario and their parasites. Canad. Dept. Agric. Publ. 1009: 1-58. (42) REEKS, W. A. (1937). The morphology of the adult of Diprion polytomum (Htg.). Canad. Ent. 64: 257-264. (43) Rose, A. H. (1952). An analysis of the development of Neodiprion sertifer (Geoff.) on four foods. M.A. thesis, University of Toronto. (44) Ross, H. H. (1937). A generic classification of the Nearctic sawflies (Hymenoptera, Symphyta). III. Biol. Monog. 15 (2). (45) Ross, H. H. (1955). The taxonomy and evolution of the sawfly genus Neodiprion. For. Sci. 1: 196-209. (46) SCHEDL, K. E. (1937). Quantitative Freilandstudien an Blatt- wespen ‘der Pinus banksiana mit besonderer Berucksichtigung der Methodik. Z. angew. Ent. 24: 25-70; 190-215. (47) WALLACE, D. R. (1959). M.Sc. thesis, Macdonald College, McGill University. (48) WELLINGTON, W. G., SULLIVAN, C. R. and GREEN, G. W. (1951). Polarized light and body temperature level as orientation factors in the light reactions of some hymenopterous and lepidopterous larvae. Canad. J. Zool. 29: 339-351. (49) West, A. S. (1952). Notes on Leconte’s sawfly. Canad. Ent. 84: 59-61. (50) WeEsT, A. S., Horwoop, R. H., FourNns, T. R. and HUDSON, Anne (1959). Systematics of Neodiprion sawflies. I. Preliminary report on ‘serological and chromatographic studies. Rep. ent. Socfl Ont. 89: 58-68. (51) YUASA, H. (1923). A classification of the larvae of the Tenthredi- noidea. Ill. Biol. Monog. 7 (4). (Accepted for publication: March 1, 1961) O THE ORIENTAL FRUIT MOTH, GRAPHOLITHA MOLESTA (BUSCK) (LEPIDOPTERA: OLETHREUTIDAE) IN ONTARIO’ G. G. DUSTAN In the fall of 1925, twelve years after the first discovery of the oriental fruit moth, Grapholitha molesta (Busck), (Lepidoptera: Ole- threutidae) in N orth America, in the District of Columbia (18), four very local, light infestations of this pest were found in peach orchards at St. Davids, Peachland, Vineland Station, and Bartonville in the Niagara 4Publication No. 5, Research Laboratory, Research Branch, Canada Department of Agriculture, Vineland Station, Ontario, prepared at the invitation of the Publications Committee, Entomological Society. of Ontario. ‘Proc. ent. Soc. Ont. 91 (1960) 1961 215 Peninsula, Ontario (22). About the same time it was also found at Olinda, Essex County. The fact that 58 per cent of the fruit was injured in 1926 in one large Elberta peach orchard at St. Davids warned that the moth was a serious threat to the peach industry. Investigations were started at the Vineland Station laboratory in 1926 and at a field station at St, Davids in 1927. This paper reviews some of the more important features of the status of the oriental fruit moth, and of the investigations that were made on its life-history, ecology, and control, during the past 35 years in Ontario. DESCRIPTION The oriental fruit moth resembles the codling moth in its life-history and appearance but is approximately one-third smaller. The adult is grayish-brown with a wing expanse of about one-half inch. The larva when young is white with a black head and when nearly full grown, pink with a brown head. The last abdominal segment carries a small, black anal comb that can be seen by careful examination with a 14-power hand lens; this is a useful feature to distinguish the larva from that of the codling moth which has no anal comb. The egg, about 0.7 mm. in diameter, is translucent, lenticular, and circular to oval in outline. Most eggs are laid on the leaves, but some are laid on smooth bark and the stem and skin of fruits, except on the fuzzy skin of peaches. The cocoons are of silk mixed with bits of the substrate. Summer cocoons are fragile and usually placed on the fruit and twigs; the winter cocoons are firmly constructed and may be found on the fruit or concealed in crevices in the bark of the tree, on trash on the ground, in fruit containers, or in crevices in or about buildings and vehicles in which the fruit may have been stored or transported. - Peterson and Haeussler (15) and Garman (14) give excellent de- scriptions of the stages and life-history, and of the features distinguishing the fruit moth from other similar or associated insects. DISTRIBUTION Four years after its first discovery in the Niagara Peninsula the fruit moth was present in practically all peach orchards of that area (22). As it is not a strong flier, natural spread probably was largely local (15) and the rapid expansion from the originally infested areas was almost cer- tainly a result of the movement of infested peaches and containers. The role of fruit containers as vehicles of spread was well illustrated at St. Davids in 1928 when an average of 20 moths per bushel hamper emerged in the spring from 600 of these containers that had been used the previous September to carry dropped peaches from a heavily infested orchard to a disposal pile. HOSTS The two principal hosts of the oriental fruit moth in Ontario are the peach and the quince; it also attacks to a much lesser degree apple, apri- cot, pear, cherry, and plum. Quince was so heavily attacked as early as 1929 (often 100 per cent of the fruit injured with 10 or more larvae per fruit) that most of the few commercial trees in Ontario were soon removed. Occasionally, when unusually warm weather prevails in late September and early October, Kieffer pears are seriously injured. LIFE-HISTORY AND HABITS Armstrong (2) and Dustan and Armstrong (10) conducted extensive investigations from 1926 to 1932 on the life-history and habits of this insect. Briefly, it passes the winter as a full-grown larva in a cocoon in crevices on the host tree or elsewhere as previously note. Approximately 216 90 per cent of the larvae that overwinter on mature peach trees were found on the lower two feet of the trunk and the remainder on the upper parts of the tree. Winter mortality averaged about 60 per cent in cages and vials in 1927-’28. Pupation starts about mid-March. Emergence of moths usually starts in late April or early May when the Elberta peach blossoms show the first sign of pink, reaches a maximum at or soon after full bloom and usually is largely completed by early June. Emergence in buildings such as fruit sheds and canning factories is often a month or more later than in the orchard and may continue into July or early August. Fig. 1. Injured peach twig showing the wilted tip above the feeding tunnel made by the larva of the oriental fruit moth. There are three full generations each year and occasionally a partial fourth in Ontario. In cool seasons, most of the third generation larvae enter diapause and overwinter. In hot years, many of them pupate and emerge and, if the weather continues warm in late September and early October, give rise to a small fourth generation of larvae. Few of these late larvae mature in the field but some may do so in the harvested fruit if it is held at sufficiently high temperatures before disposal. Dickson (7) found that the induction of diapause was controlled by temperature and photoperiod during the larval feeding period. On peach trees, about 85 per cent of the eggs are laid on the upper surface of the leaves, 14 per cent on the lower surface and the remainder on the stem of the fruit and the bark. Females lay from 30 to 60 eggs each. 217 Like the codling moth, the oriental fruit moth has a very marked, daily flight period in the evening when the eggs are laid. The incubation period of the eggs averaged 6.5 days in July and August, with a minium of 4 days. Armstrong (2) found that the length of the larval feeding period varied from 10 to 73 days, with an average of 19 days. The pupal period in the summer averaged 13 days. During June, July and August the aver- age length of the developmental period from newly laid egg to emergence of the adult was approximately 40 days, with a minimum during hot weather of 24 days. Larvae of the first two generations attack both the twigs (Fig. 1) and the fruit (Figs. 2 and 3). Twigs are preferred as long as they remain succulent, and fruit injury in May and June is usually negligible. Peaches injured by first-generation larvae usually drop during June or early July. The terminal two or three inches of the injured twigs are killed but this injury is seldom important except on young, heavily infested trees where it results in bushy growth. First-generation larvae usually attack two or three, and second-generation larvae three or four, twigs before reaching maturity. As the twigs harden, the partially grown larvae leave them and Fig. 2. Conspicuous type of injury caused by larvae feeding on green peaches during midsummer. Fig. 3. Internal injury from larvae feeding in a ripe peach. 218 enter the fruit. Fruit injury at this time of the year (July or early August) is clearly marked by the exudation of large masses of gum mixed with frass (Fig. 2). Newly hatched larvae have great difficulty in entering the flesh of the peach while it is hard and green (8, 9), but if the twigs are also too hard for the larvae, they may feed in the tender tissue of the fruit stem until they are partly grown and then successfully enter the flesh of the green fruit. About three or four weeks before harvest peaches start to soften and lose their ability to produce gum, so the larvae then can readily enter the flesh. The tiny entrance hole made by the larvae beneath the fuzz of the ripening peach, or at the junction of the stem and the flesh of the fruit, often cannot be detected. It is this externally invisible injury, comprising about 40 to 70 per cent of the total fruit injury, that makes this insect such a serious threat to the peach industry because it is impossible to cull out much of the “wormy” fruit. Larvae that enter ripening fruit usually go through to the pit and work around it (Fig. 3), while those attacking hard, green fruit remain near the surface, INFESTATION AND SEASONAL DAMAGE Various methods of assessing population density differences from orchard to orchard, from year to year, and from generation to generation have been employed. These included periodical counts of the numbers of injured twigs and fruits and of eggs on the foliage by various sampling methods, and of trapping moths in pails of sweetened bait. Twig and fruit counts were found to be influenced by so many variables, such as the size of the tree or crops, the succulency of the twigs, and the variety and stage of development of the fruit that they only roughly reflected the size and seasonal changes in population. However, ccunts of twig and fruit injury have been used to advantage to indicate marked seasonal changes in the amonut of damage. Eggs are so widely scattered and difficult to find that they are of little value as population indicators. Bait pails (22) examined at weekly or semi-weekly intervals have proved to be the most useful means of following the annual and seasonal trends in population density. Straight-sided, open-mouthed bait pails, holding about 114 quarts of bait, were maintained in one or more orchards in the Niagara Peninsula from 1927 to 1938. The bait consisted of one part cooking molasses and ten parts water. One-quarter inch mesh wire screening over the mouth of the pails excluded large insects. At St. Davids, the average number of moths trapped per pail was 139 for the week of peak abundance in September, 1927. Trapping was discontinued after 1938 and resumed in 1948 following a severe outbreak of the insect. A new bait was used, namely, that recommended by Chisholm et al. (6) consisting of one pound of brown sugar in four gallons of water to which 2.5 ml. of a 97 per cent emulsion of terpinyl acetate was added. This bait trapped thirty-three times as many moths as the old molasses bait during a 42-day period in an orchard trial at Vineland in 1948. Figures 4 and 5, and one in a paper by Ross (22) illustrate the useful type of information obtained from bait pails. The records for 1948 (Fig. 4) are fairly typical of an average season during an outbreak of the insect; they show three fairly distinct broods of moths. The growing season of 1949 (Fig. 5), by contrast, was exceptionally early and warm, with four distinct broods of moths. It will be noted that the flight of first-generation moths in June began to appear in numbers and reached its peak more than 219 ten days earlier in 1949 than in 1948. The time of this peak, and also those of later broods in relation to the two- or three-week period before harvest, are important in timing spray applications. The following brief history of the oriental fruit moth infestation in the Niagara Peninsula is based largely on bait pail catches and fruit in- jury counts at harvest. There were heavy infestations with fruit injury up 1800 ORCHARD No.2 1500, QUEENSTON MOTHS PER IO PAILS 1948 1200 900 600 300 15 10 10 20 10 20 10 20 15 MAY JUNE. JULY AUGUST SEPTEMBER OC Fig. 4. Semi-weekly catches of oriental fruit moths in bait pails in an Elberta peach orchard in 1948. to 64 per cent in a few orchards at St. Davids in 1927; most orchards else- where were lightly infested by 1928 but the amount of injury at St. Davids decreased by more than half. In 1929 a general outbreak with fruit injury up to 74 per cent occurred in many Elberta peach orchards throughout the Peninsula. For the next few years the catch of moths in bait pails steadily declined, with a corresponding decrease in fruit injury. Throughout the 1930’s the average fruit injury was light, generally less than three per cent, but there were often small local outbreaks, confined to two or three orchards with injury as high as 20 per cent. A severe outbreak occurred in Essex County in 1937 with many orchards suffering 30 to 40 per cent fruit loss. Injury in the Niagara Peninsula that year did not exceed S1x per cent in the orchards examined. There were moderate increases in 1942 and 1943 followed by a decrease in 1944 to less than one per cent fruit injury. The year 1945 marked the beginning of the severest outbreak recorded in Ontario. In 1946, many orchards near Port Dalhousie were severely injured, although the infestation was lower elsewhere in the Niagara Peninsula than in 1945. 220 In 1947, an area of heavy infestation was largely confined to a strip about one-half mile wide along the shore of Lake Ontario from Jordan Harbour to Grimsby Beach. The heaviest injury on record over most of the Niagara Peninsula and in Essex County occurred in 1948. From 1949 to 1959 the injury varied from light to moderate, but never reached the low level of the 1930’s, Elberta peaches were heavily injured late in the the season of 1959 and during the last half of August in 1960. These late-season outbreaks did not occur in Essex County. 1800 ORCHARD No. 2 1500 QUEENS TON MOTHS PERIO PAILS 1949 1200 900 600 300 10 20 ides 20 MAY JUNE 3 10 z0 : 10 20 10 20 JULY AUGUST SEPTEMBER OCT. Fig. 5. Semi-weekly catches of oriental fruit moths in bait pails in an Elberta peach orchard in 1949. ECOLOGY Abiotic Factors Armstrong (2), in his life-history studies under approximately out- door temperatures found that the lengths of the developmental periods and of adult life varied inversely with temperature. Dustan and Armstrong (10) reported more fully on the effects of temperature, light and moisture. They showed that light was the chief factor limiting the length of the daily egg-laying period; normally about 98 per cent of the eggs are laid from three hours before to one hour after sunset. Egg-laying could be induced earlier in the day by partially shading the cages and was prevented by excluding all light. They also showed that egg-laying stopped when the temperature dropped below 58° F. The optimum temperature for egg- laying was about 91° F.., and it was greatly reduced at 95 to 96° F. When caged moths were not supplied with water their life-span was reduced, compared to those with water, from about 15 days to 7 days, and the aver- 221 age number of eggs per female from 29 to 7. I (unpublished) also showed that, at least under cage conditions, wind considerably reduced egg-laying. Under calm conditions females laid about 41 eggs each but in wind of from five to six miles per hour the number was reduced to 18 per female. Temperature differences, caused largely by exposure to sunshine, had an effect on the length of the spring pupal period and the time of emer- gence of the spring brood of adults; emergence started later and extended over a longer period on the north sides of the tree trunks and in the shade of buildings than in the direct sun. Dustan’s experiments (8, 9) in 1928 and 1929, on the feeding habits and mortality of newly hatched larvae under natural conditions on bearing peach trees, produced information that proved valuable when effective in- secticides became available. These experiments showed that during May and June about 22 to 67 per cent of the newly hatched larvae attacked the twigs and most of the remainder the woody stem of the fruit. Establishment mortality during this time varied from about 30 to 55 per cent. As the twigs hardened in July initial feeding on the twigs almost ceased whereas larvae feeding in the woody stem of the fruit increased to about 85 to 95 per cent, the rest of the young larvae feeding in the flesh of the fruit. The establishment mortality was then at its highest for the season, and varied from about 75 to 938 per cent. These conditions continued during July and part of August; during this period the fruits make little growth, the pit is hardening, and the flesh is hard and produces gum when injured, About three or four weeks before harvest, when the fruit starts to soften and loses its ability to produce gum (usually about mid-August for Elberta peaches), the proportion of newly hatched larvae that directly attacks the flesh rapidly increases to about 90 per cent or higher, and there is at the same time, a corresponding decrease in establish- ment mortality to as low as four per cent near harvest. These findings indicated that insecticides would exert their greatest apparent effect in midsummer when they would be aided by natural mortality of larvae entering green fruit, but that the need of insecticides was actually greatest when the fruit was ripening and the larvae could easily enter it. During the spring of 1934, following the coldest winter since the oriental fruit moth was discovered in the Niagara Peninsula, Dustan (11) showed by means of emergence from overwintered larvae, bait pail catches, and twig and fruit injury records that the oriental fruit moth successfully survived temperatures as low as (-17°F.) which killed all the peach buds in some orchards. From 1931 to 1935, W. L. Putman and G. G. Dustan (unpublished) conducted an investigation in bearing and adjoining young, non-bearing orchards at four widely separated points in the Niagara Peninsula in an attempt to account for differences in egg, larval, and adult population densities caused by parasites and predators, and by differences in temper- ature and wind velocity. Although this study produced much information (some of which was published on parasites and predators) it failed to reveal any consistent reasons for the observed differences in population density, except that the densities were more or less inversely proportional to the extent of parasitism by Macrocentrus ancylivorus during the later years of the investigation. Since that time, Dustan and Boyce (unpublished) have repeatedly attempted to find reliable indicators from population studies, weather con- ditions,. and parasite abundance on which to base predictions of outbreaks or marked changes within seasons. So far, these attempts have been largely unsuccessful because of the variety and inconsistency of the many factors 222 concerned. It can be stated, however, that the following conditions are generally likely to result in an increase of the moth in any one season: (a) comparatively cool weather in May followed by high temperatures in June when the spring brood of moths is at or near its peak of abundance: (b) sufficient rain and moderate temperatures in July so that peach twigs remain succulent throughout much of the feeding period of the second generation; (c) high temperatures and relative humidity in August and September when peaches are ripening; and (d) unusually low parasitism. Further study of past records, now under way by Dustan and Boyce, may reveal more reliable means of predicting the occurrence of periods of peak abundance and the threat of serious fruit injury. Parasites | The parasites of few insect pests in North America have received as much attention as those of the oriental fruit moth. Larval parasites have been abundane and relatively successful for many years in Ontario, especially in the Niagara Peninsula, but unfortunately they cannot be relied upon to give the consistently high degree of control required by the peach industry. Smith’s (23) initial investigations in Ontario in 1928 revealed a very low degree of parasitism by native species and in 1929 van Steenburgh (25) reported that it averaged only 2.2 per cent for all larval collections. However, the situation changed rapidly and in 1931 the activity of Glypta rufiscutellaris Cress. increased phenomenally, By 1934, 44 other native species had been collected, most of them in very small numbers. Cremastus minor Cush. and Horogenes obliteratus (Cress.) were significantly active some years, but most of the mortality was caused by G. rufiscutellaris. A parasite, Macrocentrus ancylivorus Rohwer, that had been very successful in New Jersey was introduced from there to Ontario in 1929 and 19380. It established itself readily, spread rapidly, and after further releases from local collections was soon present in practically all peach orchards in the Niagara Peninsula. Its establishment in Essex County was less successful and it appeared to die out within four years of the initial releases in 1930. However, after releases of 16,000 and 11,000 adults in 1935 and 1936 it became well established and was an important factor in controlling an outbreak of the fruit moth in Essex County at that time (26). Further large releases were made in 1947 and 1948. Unfortunately, as Boyce (4) and, later, Boyce and Dustan (5) reported, parasitism by M. ancylivorus in Essex County peach orchards has been generally much less than in the Niagara Peninsula. Boyce and Dustan (5) also showed that M. ancyliworus was dominant over other common local species of parasites of this host and that as it increased in numbers G. rufiscutellaris became less successful. Between 1928 and 1934 van Steenburgh (26) conducted extensive experiments with the egg parasite Trichogramma. Almost 30 million, laboratory-reared individuals were released during this work, but, though appreciable control of fruit moth eggs was secured in some cases where the host populations were high, this method was of little economic value. It has been relatively easy to assess annually the degree of parasitism of twig-feeding oriental fruit moth larvae of the first two generations, but much more difficult to evaluate the role of parasites in controlling the fruit moth, In many years average parasitism of the first generation in the Niagara Peninsula, largely by M. ancylivorus, ranged from about 42 to 64 per cent, and of the second generation from 60 to 85 per cent. In several years moderate increases or outbreaks of the fruit moth coincided 223 with comparatively low parasitism, for example, in 1942, 1945, and 1948 in the Niagara Peninsula, and 1937 in Essex County. Again, in several cases declines of the host have been accompanied by increases in parasit- ism, notably in 1946, 1949, and 1950.However, weather conditions and the condition of the peach twigs and crop were often suspected to be equally or more important factors than parasitism. There have been a number of years with high larval parasitism when the numbers of moths and amount of injury to peaches were also high. Finally, the fact that the moth in- festation has generally been higher in the Niagara Peninsula than in Essex County, despite consistently higher parasitism in the former area, leads to the conclusion that the degree of parasitism is seldom the chief factor regulating the population density of the oriental fruit moth. Nevertheless it is believed that the general level of the moth infestation would be higher, perhaps considerably so, if parasites were absent. Smith and Driggers (24) reported that DDT was toxic to caged adults of M. ancylivorus. Rings and Weaver (19) and Allen (1) demonstrated significantly lower parasitism in peach orchards sprayed with DDT than in unsprayed checks, though Allen concluded that the potential capacity of parasites to reduce oriental fruit moth populations was not appreciably affected by the general use of new insecticides, including DDT. Boyce and Dustan (5)* demonstrated that, when DDT was applied to peach trees four days after the peak flight of the first generation of the oriental fruit moth, parasitism of the succeeding generation of moth larvae by WM. ancylivorus was significantly lower than when DDT was applied four days before peak flight, the percentages of parasitism under these con- ditions being 6.7 + 6.7 and 43.4 + 12.4 respectively. Nevertheless, Boyce and Dustan (5) showed that parasitism by M. ancylivorus has actually increased since DDT came into general use in Ontario peach orchards in 1948, This also held true following the use of parathion in 1949 and later years. On the other hand, G. rufiscutellaris has almost disappeared in peach orchards since the use of these insecticides, especially in the Niagara Peninsula. There is no evidence that M. ancylivorus developed resistance to DDT or parathion; how it escapes their toxic effect in the orchards is not known. Predators Years of observations in peach orchards have indicated that in most years the role of predators in reducing the oriental fruit moth population is probably a minor one, with the possible exception of the years 1930 and 1931 when chrysopids appeared in large numbers in many peach orchards and destroyed large numbers of eggs. Putman (16) showed that Chrysopa rufilabris Burm. and C. plorobunda Fitch were the species of most im- portance. Putman (17) also found that Haplothrips faurei Hood (misidentified as H. subtilissimus Hal.) attacked eggs of the oriental fruit moth but was too scarce in peach orchards to be of any significance as a control agent. CONTROL Many types of control operations, other than by parasites and pre- dators, have been attempted against this pest but before the use of DDT none was effective during cycles of abundance. Neither lead arsenate nor nicotine sulphate, two of the most effective insecticides available during the early years of the infestation, gave appreciable control, though the 2Boyce and Dustan inadvertently reversed the order of the percentages of parasitism in lines seven and eight of the fourth paragraph on page 495 of this paper. 224 latter killed some eggs. The failure of lead arsenate was apparently due _ in part to the habit of the newly hatched larvae of discarding most of the first particles they removed when starting a feeding tunnel and in part to the difficulty of keeping the rapidly growing peach shoots covered with the poison. Although high kills of overwintering larvae were obtained by various oils (21), of summer feeding larvae by inert powders such as tale and china clay (20), and of eggs by oils and oil-pyrethrum (20), the control in orchard trials was negligible. Armstrong’s experiments (3) showed that almost 100 per cent of the larvae that overwintered on the so.l or soil debris were killed by thorough cultivation with a disc harrow, but as only a comparatively small percentage of the larvae spend the winter in these situations this measure was of limited value, though recommended for many years. Holding in- fested peach containers in closed rooms until emergence was completed In the spring, or, in the case of canning factories, killing the larvae in the containers with live steam, helped to prevent the spread of large numbers of moths to nearby orchards. Dustan et al. (12) reported at length on their largely successful ex- periments on controlling the oriental fruit month with DDT or parathion. At first, a single spray of 50 per cent DDT at 2 lb. per 100 gal. three to four weeks before harvest, with an additional application two weeks earlier on the late variety Elberta, was recommended to protect the ripening fruit which is most susceptible to attack. During the outbreak of 1948 and later it was found profitable to apply two additional sprays about 12 days apart against the second-generation larvae in late June or early July. In heavy infestations it was also profitable to apply two more sprays in May or early June against the first generation. The May and June sprays coincided with those for the plum curculio and parathion was effective against both insects. The first spray against the second generation is best applied when eggs are starting to hatch in appreciable numbers. This is usually two or three days before the peak catch of first generation moths in bait pails and the date can be estimated quite closely about a week ahead by the trend in the pail catches. Chemical control posed the problem of residue hazards to the con- sumer. Dustan et al. (12) showed that it was difficult to meet the tolerance of 7 p.p.m. of DDT by the recommended spray of 2 lb. of 50 per cent powder three weeks before harvest. However, despite United States’ recommendations that DDT should not be applied on peach later than 42 days before harvest, Dustan and Chisholm (13) found that the tolerance was not exceeded if 1 lb. of 50 per cent DDT was applied 25 days before harvest and this became the official recommendation. This reduced rate did not, however, give adequate protection in years when the moth was abundant and DDT will not be recommended in this application in 1961, A search for safer and more effective substitutes for DDT in the pre- harvest spray was conducted without success until 1958 and 1959, when Dustan (uunpublished) showed that 114 lb. of 25 per cent Guthion’® powder per 100 gal. of water, applied 21 days before harvest, or 2 lb. of 50 per cent Sevin* powder, one or two weeks before harvest, were much more effective than 1 lb. of 50 per cent DDT or 114 lb. of 15 per cent parathion applied 25 to 21 days respectively before harvest. These materials are $0,0-dimethyl S-4-Oxo-1,2,3-benzotriazin-3 (4H)-ylmethyl phosphorodithioate 41-naphthyl N-methylcarbamate 225 now being recommended despite their higher cost. Dustan’s experiments also showed that Guthion was also somewhat more effective than DDT or parathion in the earlier sprays. As Sevin can be applied up to one day before harvest on peach, it is also being recommended as an emergence treatment when serious injury threatens near harvest, after the residue of the regular pre-harvest spray (the “third cover spray” in Ontario) has lost much of its effectiveness. | Experiments made at Vineland have repeatedly shown that adequate amounts of spray (about 4 gal. of conventional, “‘dilute’’ spray per mature peach tree) and good coverage are needed to obtain satisfactory control of this insect. Many growers fail in both respects, especially since the general adoption of automatic, air-blast sprayers that they tend to drive too quickly past the trees. It has been demonstrated that these machines, properly operated with either “dilute” or “concentrate” sprays, are about as effective as hand spraying with a gun or broom. At the present time peach growers in Ontario must rely on insecticides to control the oriental fruit moth, and they obtain the best results by spraying both bearing and non-besring orchards with two sprays for the first generation, two for the second, and one for the third or fourth gener- ation. Investigations will be continued as the peach industry must be supplied with up-to-date information on control practices, secured largely by experiments with insecticides. It is essential, however, that research must continue and expand on all fronts, such as the harmonizing of chemical and biological control, the more effective utilization of old or new parasites and predators and, possibly, disease organisms; and on biological, physical and chemical agents with entirely new modes of action, if and when such are discovered. 5 LITERATURE CITED (1) ALLEN, H. W. (1958). Orchard studies on the effect of organic insecticides on parasitism of the oriental fruit moth. J. econ. Ent. DL S21 s (2) ARMSTRONG, T. (1929). Notes on the life history of the oriental peach moth at Vineland Station. Rep. ent. Soc. Ont. 59: 65-72. (3) ARMSTRONG, T. (1933). Studies on the effect of burying and of cultivation on larvae of the oriental fruit moth. Rep. ent. Soe. Ont. 63: 24-29. (4) Boycr, H. R. (1947). Long term trends in parasitism of twig- infesting oriental fruit moth larvae. Rep. ent. Soc. Ont. 77: 21-34. (5) Boyce, H. R. and DuSTAN, G. G. (1958). Prominent features of parasitism of twig infesting larvae of the oriental fruit moth, Grapholitha molesta (Buseck) (Lepidoptera: Olethreutidae), in On- tario, Canada. Proc. 10th int. Congr. Ent. 1956, 4: 493-496. (6) CHISHOLM, R. D., YETTER, W. P. Jr., and BRUNSON, M. H. (1946). Baits for the oriental fruit moth. J. econ. Ent. 39: 399. (7) Dickson, R. C. (1949). Factors governing the induction of diapause in the oriental fruit moth. Ann. ent. Soc. Amer. 42: 511-537. (8) DUSTAN, G. G. (1930). Preliminary notes on the mortality and feed- ing habits of newly-hatched oriental peach moth larvae. Rep. ent. soc. Ont. 60: 108-111. (9) DusTAN, G. G. (1931). Further notes on the mortality and habits of newly-hatched oriental peach moth larvae. Rep. ent. Soc. Ont. 6h: 52-57. 226 (10) (11) (12) (13) (iz) (15) (16) (17) (18) (19) (20) (21) (23) (24) (25) (26) DUSTAN, G. G., and ARMSTRONG, T. (1933). Observations on the relation of temperature and moisture to the oriental fruit moth. Rep. ent. Soc. Ont. 63: 29-39. DUSTAN, G. G. (1935). The effects of the cold winter of 1933-34 on the oriental fruit moth. Canad. Ent. 67: 65-68. Dusman, G: G.; PUTMAN, W.'L. and Boyce, H.R: (1957). Results of spraying for the control of the oriental fruit moth, Grapholitha molesta (Busck), in Ontario, 1946-1950. Rep. ent. Socfl Ont. 81: 50-72. DUSTAN, G. G. and CHISHOLM, D. (1959). DDT residues on peach in Ontario. J. econ. Ent. 52: 109-110, GARMAN, P. (1930). The oriental peach moth in Connecticut. Conn. der xpi Sta. Bull) g13: 400-451. > PETERSON, A and HAEUSSLER, G. H. (1926). The oriental peach moth. United States Dept. Agr, Cire. 395. PUTMAN, W. L. (1932). Chrysopids as a factor in the natural control of the oriental fruit moth. Canad. Ent. 64: 121-126. PUTMAN, W. L. (1942). Notes on the predaccous thrips Haplothrips subtilissimus Hal. and Aeolothrips melaleucus Hal. Canad. Ent. 64: 37-43. QUAINTANCE, A. L, (1916). Laspeyresia molesta, an important new insect enemy of the peach. J. agr. Res. 7: 373-377. RINGS, R. W. and WEAVER, C. R. (1948). Effects of benzene hexa- chloride and DDT upon parasitism of the oriental fruit moth. J. econ. Ent. 41: 566-569. | Ross, W. A., ARMSTRONG, T. and PATTERSON, D. F. (1929). Some oriental peach moth control studies with special reference to the use of lime and talc sprays. Rep. ent. Soc. Ont. 60: 116-124. Ross, W. A., HALL, J. A. and ARMSTRONG, T. (1929). Experiments with larvicides directed against overwintering codling moth and oriental peach moth caterpillars. Rep. ent. Soc. Ont. 60: 40-48. SMITH, C. W. (1929). Parasitism of the oriental peach month in Ontario with special reference to biological control experiments with Trichogramma minutum Riley. Rep. ent. Soc. Ont. 59: 72-80. SMITH, C. L. and Driccrers, B. F. (1944). Toxicity of DDT to Marcrocentrus ancylivorus Rohwer, J. econ. Ent. 37: 538. STEENBURGH, W. E. van (19380). Notes on the natural and introduced parasite of the oriental peach moth (Laspeyresia molesta Busck) in Ontario. Rep. ent. Soc. Ont. 60: 124-130. STEENBURGH, W. E. van and Boyce, H. R. (1938). Biological control of the oriental fruit moth in Ontario: A review of ten years’ work. Rep. ent. Soc. Ont. 69: 65-74. (Accepted for publication: March 1, 1961) O 227 a iy | : ATTLE GRUBS (DIPTERA: HYPODERMATIDAE) IN ONTARIO’ f H, J. TESKEY’ INTRODUCTION The cattle grubs, Hypoderma lineatum de Villers and Hypoderma bovis (Linnaeus), are considered among the more injurious insect pests of cattle throughout much of the north temperate regions of the world. They are particularly injurious in parts of Europe and North America. — Hypoderma lineatum is the more widely distributed of the two species in North America, occurring in most areas where cattle are raised. Hypo- derma bovis is restricted to Canada and the northern half of the United States. | Although not as abundant in Ontario as elsewhere, cattle grubs have been of importance because of the intensive type of animal husbandry practised, the density of the cattle population and the high value of the anima! products obtained. The losses to the animal industry in the province attributed to cattle grubs has long worried the more progressive owners and processors of cattle. The interest and actions of these people have culminated in the province having one of the largest cattle grub control programs in North America. Thus, it is fitting that the cattle grubs be chosen as one of the subjects of review for the re-initiation of this section on destructive and useful insects of Ontario. _ It is not known how long cattle grubs have been present in the prov- ince. Stevenson (25) states that H. lineatuwm was responsible for all or the greater part of the injury to Ontario cattle as early as the 1830's. Hypo- derma bovis was not known to be present in Canada before 1912 (6). The paucity of information on cattle grubs in the 19th century liter- ature from Ontario would indicate their possible minor importance. How- ever, cattle grubs were numerous about 1912 since tanners in Ontario reported that 44 per cent of the hides were damaged during the season when the larvae were in the backs of cattle (6). The increased importance of damage appeared to have coincided with the increase of H. bovis. Loch- head (16) reported an outbreak of this species in cattle of two southern counties of Quebec, adjacent to Ontario. He attributed this outbreak to large importations of cattle from Scotland during the two or three years prior to 1915. In the discussion of the above paper, A. F. Winn stated “Tt is apparent that warble flies are becoming more frequent” and, “In the old days the only species recognized in this country was Hypoderma lineata which was considered the truly native species’. Stevenson (25) also refers to the increased importance of H. bovis as beginning about 1912 and infers that the species was abundant in Ontario in 1934. The species change continued for Baker et al (1) reported that almost all of the 11,104 larvae extracted from cattle in two southern Ontario counties in 1949 were H. bovis. This observation was subsequently confirmed by the writer (28). Although H. lineatum has not been found in native cattle in recent years and would appear not to breed normally in the province, many are introduced every year in feeder cattle originating from western Canada. iThis paper was prepared at the invitation of the Publications Committee, Entomological Society of | Ontario. 2Entomology Laboratory, Research Branch, Canada Department of Agriculture, P.O. Box 248, Guelph, Ontario. Proc. ent. Soc. Ont. 91 (1960) 1961 228 6 The species is thus still of considerable importance to some cattlemen in i — the province, in that they are purchasing “built-in” damage. DESCRIPTIONS The corresponding stages in the growth and development of both species of Hypoderma are very similar. With the exception of the third stage larvae, which is the only stage commonly observed, the following descriptions will be very brief and will not serve to distinguish between the two species. Accurate identification of all stages of both species can be made by referring to James (10). : Fig. 1. Adult female of Hypoderma bovis. Fig. 2 Eggs of Hypoderma bovis, left, and Hypoderma lineatum, right. Figs. 3-6 First, second, and third stage larvae, and a puparium of Hypoderma bovis, respectively. Fig. 7 Posterior stigmatal plates of third stage larvae of Hypoderma bovis, left, and Hypoderma lineatum, right. 229. fs The adults of the cattle grubs are dark, hairy flies with bands of yellow or orange that give them a superficial resemblance to small bumble- bees. Functional mouthparts are absent. Hypoderma bovis (L.) (Fig. 1) is the larger of the two species; slightly over one-half inch in length. The eggs of cattle grubs are dull yellowish-white with an oval clasp at one end by means of which they are attached to the hairs of cattle. The eggs of H. bovis are always laid singly on the hairs, while those of H. lineatum are normally attached in rows (Fig. 2). Cattle grub larvae pass through three stages of growth, each very much different from the others. The first stage is of the longest duration requiring approximately eight months. Larvae of this stage, as typified by those found in the sub-mucosa of the oesophagus or in the spinal canal, range in size from about one to 13 mm., are elongate, cylindrical, tapered slightly from the centre in both directions and bluntly rounded at both ends (Fig. 3). They are white or cream colored and partly trans- parent. No cuticular markings such as spines or pubescence is evident on casual observation. The second stage larva is the first of two stages that occur in the backs of cattle. The larvae are now about 15 mm. in length, light in color, and their skins are closely set with patches of dark spines (Fig. 4). The greatest size increase to about 30 mm. in length and 12 mm. in diameter occurs during the last stage. The skin is rugose and the seg- ments are encircled by armatures of blunt spines (Fig. 5). The color gradually darkens from yellow to almost black during this final stage. Although the two species are very similar in the third stage, they can be readily differentiated by the character of the posterior stigmatal plates which are deeply excavated and funnel-like in H. bovis and flattened in H. lineatum (Fig. 7), and the absence of ventral spines on the tenth segment of H. bovis. The pupae, which are rarely found in nature, are enclosed in the outer skin of the last larval stage. This skin hardens and darkens to form a protective case or puparium in which the change to the adult fly occurs (Fig. 6). LIFE HISTORY The first observations of a scientific nature on the biology of cattle grubs were published in 1710 by Vallisnieri, an Italian naturalist (3). Since that time many erroneous conclusions have arisen regarding the life history of cattle grubs. Such conclusions have involved the site of ovi- position, mode of entrance of larvae to the animal body, and the route of larval migration to the back. One of the earliest views was that the backs of animals were pierced by the ovipositor, the pain produced being the cause of gadding. This view was held until the late 1890’s despite the earlier demonstration of the unsuitability of the ovipositor for such a task. The piercing theory was then abandoned for cne in which the eggs were laid on the skin of the back. Following the nearly concurrent discoveries of cattle grub larvae in the walls of the gullet and the correct oviposition site on the hairs of the lower extremities of the animal, theories of the mode of entrance of the larvae to the body were changed to one whereby eggs were licked off the hairs, hatched in the mouth, and the young larvae penetrated the gullet wall. Due in large part to the studies of Carpenter et al (4) in Ireland, and Hadwen (6, 7) in British Columbia, the correct site of entry of larvae into the body was made known. These findings put an end to the myths surrounding the life history of cattle grubs and can be said to have ushered in a new era in our understanding of these pests. Subsequent studies, based on this firm foundation, have elucidated the life 230 history with the exception of the exact route followed by larvae through the host. These studies have been ably reviewed by Bishopp et al (3) and Scharff (24). The life history of the two species of cattle grubs are essentially similar. They differ in oviposition habits, migration routes, and seasonal occurrence. The seasonal occurrence differs not only between the two Species but also between various areas of the continent. The seasonal de- velopment of the hypodermal stages of the larvae in Ontario has been studied by Kingscote (13) and the writer (27). These, plus unpublished observations of the writer on the time of the year that larvae are present in the spinal canal give a fairly complete seasonal history of H. bovis for Ontario and shall be used in the following discussion. The seasonal develop- ment of H. lineatuwm preceeds H. bovis by about six weeks. Oviposition takes place most commonly on warm, sunny, quiet days from June to September. The eggs are placed on the hairs of the legs and lower portions of the body of cattle. Hypoderma lineatum frequently de- posits her eggs on recumbent stock without their being aware of her presence. Hypoderma bovis attacks cattle viciously and persistently, gener- ally causing a considerably greater amount of terror in herds. The larvae hatch from the eggs in two to six days, depending on the temperature, crawl down the hairs and penetrate the hide. A period of about eight months follows during which the movements of the larvae are not well known. Evidence indicates that they migrate only in connective tissue. Although a few may possibly migrate in such tissue directly to the back, most larvae of H. lineatum go first to the sub-mucosa of the cesophagus and H. bovis larvae enter the spinal canal where they move about in the epidural fat before continuing their journey. Why the two species end up after their long migrations in these localities, and what stimuli are in- volved in directing their movements is not known. Hypoderma bovis larvae have been found in the epineural connective tissue along nerves and pre- sumably by following this tissue with the aid of geotaxis could consistently reach the spinal canal. The mechanisms directing the movements of H. lineatum to the oesophagus are more difficult to explain. Larvae of the two Species are most. commonly found in the sub-mucosa of the oesophagus and in the spinal canal during December and January. However, it is not known how long individual larvae may stay in these locations before con- tinuing their migrations to the subdermal tissues of the back. The first act of the larvae on reaching the back of the host is to make breathing apertures through the hide. While in the back the larvae moult twice, the first moult occurring from one to five days after reaching the back and the second about 30 days later. Synchronous with the first moult, walls of dense connective tissue are formed rapidly about the larvae to produce the characteristic warbles. During the entire period in the back the larvae lie with the two spiracles on their posterior ends applied closely to the openings in the skin, feed on the pus and bacteria that accumulate within the warbles, and grow rapidly. While growth proceeds the holes in the skin gradually enlarge. At the completion of the develop- mental period the mature larvae work their way out of the enlarged openings and drop to the ground. Emergence from the back generally occurs on bright sunny mornings. The first larvae of H. bovis puncture the skin early in February, although records in January have been reported. Arrival of larvae in the backs of cattle follows a normal curve with maximum arrivals being near the middle of March and ending as late as June 1. Developmental 231 time for the hypodermal stage of the larvae was found to vary from about 50 to 120 days with a mean of 80 days. Emergences of larvae occurred from about May 1 to August with a peak about June 1. On reaching the ground the larvae seek sheltered spots under grass or debris, or, may burrow into soft soil a short distance. Within 12 hours to several days the puparia are formed within which pupations occur. The length of the pupal stage varies considerably depending on temperature but averages about 30 days. Sexually mature flies emerge from the puparia again on bright sunny mornings. Mating may occur within an hour of emergence and fertile eggs may be laid 20 minutes after copulation. Because the adults are without functional mouthparts and must depend on the nutrients stored during the larval stages, their life is relatively short. ECONOMIC IMPORTANCE Estimates of the losses attributable to the injuries caused by cattle grubs have been proposed at various times for parts of North America and Europe. All run into the millions of dollars. Loss estimates of $7,000,000 to $14,000,000 for Canada and $5,000,000 for Ontario were quoted in 1932 and 1934 (9, 25). Losses in damaged hides constituted about one- tenth of these estimates. The injuries produced by cattle grubs may be divided into two groups, 1) those caused by flies during the deposition of eggs, and 2) injury caused by larvae within the body of the host animal. The first group of injuries occur as a result of the terror-stricken running, or gadding, of cattle being chased by cattle grub flies. In this connection, H. bovis is known to cause a greater degree of fright in cattle and thus would presumably be more injurious. The losses resulting from gadding may be expressed in terms of productivity losses (reduced milk yield and failure to put on flesh normally) and various mechanically incured losses such as broken legs from stepping in holes, lacerations from entanglement in fences and brush, and others. The only documentation available on these losses have been made by farmers. Bishopp et al (3) stated that the dairymen, in areas where gadding was severe, estimated that milk production was reduced 10 to 25 per cent during the fly season. Many Ontario farmers have attributed decreased milk production and slower weight gain in their cattle to gadding. The second group of injuries begin with the penetration through the skin of newly hatched larvae, That cattle are irritated by these larvae is obvious from their licking the affected parts and kicking and stamping the feet. Host reaction to the penetration of these larvae causes a condition known as hypodermal rash. Little is known of the annoyance caused by the larvae migrating through the tissues of the host. Presumably it may influence the productivity of cattle. Occasional instances of paralysis in the posterior parts of cattle have been attributed to larvae injuring a nerve while burrowing along the spinal canal. The most evident. injury is produced in the hides and carcasses after the larvae have reached the back. The breathing holes are cut in the most valuable portions of the hide. Injury to hides is not restricted to the warble Season, since blemishes remain in the leather and the new tissues are weaker. Although hide damage was heavily stressed in the early literature on the economic importance of cattle grubs (3, 8, 19) more attention is now being given to carcass damage. Host reactions to hypodermal larvae results in the accumulation of masses of yellow, gelatinous tissue in the fat and flesh. This unsightly tissue must be trimmed from the carcass. 232 Frequently the trimming must be so extensive as to result not only in the loss of the trimmed tissue but also the devaluation of the carcasses or individual cuts of meat. The losses resulting from damaged hides and carcasses are the eastiest to estimate because they are so evident. In 1912, Hadwen (6) re- ported that an average of 44 per cent of the hides received by Ontario tanners during the warble season were damaged to the extent of 50 cents to one dollar a hide. Stevenson (25) stated that 30 per cent of the hides marketed in Ontario in 1934 were damaged by cattle grub larvae which resulted in a loss in excess of $500,000. The most recent attempt to evaluate the damage done by the larvae to hides and carcasses was re- ported by the Meat Packers Council of Canada (18). Trim and devaluation of carcasses, and hide losses were assessed between February 17 and April 26, 1958 by fifteen member plants of the Council in Alberta, Saskatchewan, Manitoba and Ontario. Some of the results of the survey, as summarized in Table I, show the great variation in, and extent of the losses in the four provinces. Of particular interest is that carcass losses, through trimming and devaluation, exceed the hide losses during the warble season, TABLE I Trim, carcass devaluation, and hide loss caused by cattle grubs as determined in meat packing plants of four Canadian provinces between February 17 and April 26, 1958 Average Loss per Animal in dollars Infested Cattle All Cattle Devalu- Devalu- imm:))-abpion. tides »Total=>, brim > ation Hides - Total Alberta 1.86 1.38 Mo Pot 46 .65 sok AZ Saskatchewan .51 Boe e684 .08 07 al 0.26 Manitoba aL 1.11 9S. 1.50 .06 55 18 0.79 Ontario 16 2.81 Oe one .02 7b) 18 0.35 Four Provinces .65 1.40 .63 2.68 16 40 il 0.77 Because the data in Table I was based on the province of slaughter rather than the province of origin of cattle, the figures for Ontario do not represent losses to Ontario bred cattle alone. Cattle from other areas, mainly western Canada, are transported into Ontario for slaughter each year. The fact that cattle from western Canada are known to be infested with a higher average number of larvae than native cattle serves to ex- plain the relatively high losses in infested cattle listed for Ontario. Decreased productivity of cattle resulting from infestations with cattle grubs have frequently been claimed as being of major economic im- portance. Accurate information on this subject is very scanty and con- troversial. Scharff (24) has reviewed the earlier literature that favors the hypothesis. The value of much of this information is restricted by the numbers of cattle on which it was based and by various other conditions that existed during the experiments. The development of effective systemic insecticides has facilitated the accumulation of more information on productivity losses. With systemic insecticides it is possible to assess productivity losses caused by migrating larvae as well a hypodermal larvae. Most of this new data shows no significant retarded weight gains caused by cattle grubs (11, 12, 15, 20, 21, 22, 23, 29). Some of this information 235 was obtained using cattle in which the controls were infested with an average of more than 30 larvae per animal. Although productivity losses did not occur under the conditions of these experiments, they may actually have existed but were masked by other factors. The possibility of systemic insecticides themselves retarding the weight gain of cattle needs further study. Turner and Gaines (30) found that reduced weight gains of beef cattle caused by cattle grubs were related to the ration that the cattle were fed. Systemic insecticide treated cattle on full feed rations gained significantly more weight than similarly fed controls, where as weight gains did not differ between treated and control cattle fed only a sub- sistence ration. CONTROL All stages in the development of cattle grubs have been investigated for avenues to their control (24). The control of adults appears virtually impossible because of their elusive habits and the fact that they do not feed. Attempts at preventing oviposition, destroying eggs or newly hatched larvae, and immunization were unsuccessful. Until recently, the only effective control of cattle grubs involved the extraction from, or killing larvae in the backs of cattle. Of the many chemicals tested for this purpose, rotenone as found in ground derris and cube root, has been the most effective and practical material. Solutions of rotenone, alone or mixed with soap or sulphur and applied to the backs of cattle by scrub brush or high pressure spray were the only accepted methods of controlling cattle grubs. Within the last decade the development of the organophosphorus in- secticides, Ronnel (O, O-dimethyl O -(2, 4, 5-trichlorophenyl) phosphoro- thioate) and Co-Ral (O- (38-chloro-4-methylumbelliferone) O, O-diethyl phosphorothioate), have revolutionized the control of cattle grubs. Not only are they highly effective but because of their systemic action they are capable of killing larvae in the early migratory phases before much damage to cattle has occurred. These compounds have also proven effective in kill- ing other livestock parasites, notably cattle lice. Thus, an added advantage to their use is that a properly timed treatment can effectively control more than one pest insect. The effectiveness of both of these compounds has been demonstrated in Ontario (14; W. P. Watson, Ontario Livestock Commissioner, personal communication). Certain disadvantages limit the use of Ronnel and Co-Ral for the control of cattle grubs. Because the residues of these compounds deposited in the milk and tissues of animals may have deleterious effects on humans consuming such contaminated products, they cannot be used on milking cows or cows likely to be in milk within 60 days, or on animals to be slaughtered within 60 days. These are not serious disadvantages. For various reasons milking cows usually have fewer larvae that can be readily removed by conventional methods. The timing of treatment for beef cattle can frequently be altered to conform with the 60 day limit imposed. The greatest factor against the general use of systemic insecticides for cattle grub control is their cost. Because treatments are made before larvae reach the back, all cattle, whether infested or not, must be treated. It is questionable if the cost of treatment is refunded in increased product value, in areas such as Ontario, where the average number of larvae per animal is low and many cattle are uninfested. However, in many herds perennially infested with cattle lice, the combined control of lice and cattle grubs would probably realize economic benefit. For these reasons, penne will continue to be widely used to kill hypodermal stages of cattle grubs, 234 Control practises aimed at killing hypodermal larvae have presented many difficulties. Because most of the damage caused by cattle grubs occurs before control can be initiated, the success of the control must be measured by the reduced larval infestation and injury to cattle in sub- sequent years. Although the adults of cattle grubs probably do not fly very far, experience has shown that an individual cattleman can expect only moderate success in controlling cattle grubs if others in the vicinity fail to do so. The level of control is thus related not only to the percentage kill but also the area over which it is achieved. Any value to be derived from killing hypodermal larvae is dependent, therefore, on the co-operation that can be obtained between livestock owners in a district; the larger the district the more effective and lasting will be the control. This principle of co-operation has and will continue to govern attempts at controlling cattle grubs as long as destruction of the hypodermal stages of larvae prevails. Many programs of control by systematic destruction of larvae in the cattle in districts both large and small have occurred (24). All showed benefits in reduced damage as long as the co-operation of all cattle owners was maintained. Control programs in Ontario are excellent examples (5, 25, 26). The first such program began in 1932 in Barrie Island Township, Manitoulin District. In the following four years the population of larvae was reduced from an average of 23 to 0.7 per animal. Benefits were received in improved hide and carcass quality. Gadding was not reported after the second year’s work. Similar benefits were obtained from the treatment on Manitoulin Island of 20,000 cattle in 1933 and 1934 and in demonstrations on Scugog and Thorah Islands, Ontario township in 1933. The interest thus aroused spread rapidly. In Oxford and Elgin counties, two of the more progressive dairy farming areas in the province, approxi- mately 110,000 cattle were treated in 1934. The numbers of larvae were greatly reduced by treating ail of the cattle twice and some a third and fourth time. The cost of the treatments averaged three cents a head and was paid for by the county councils. The program was repeated in 1935 and 1936. Cattle in the counties of Middlesex, Lambton, Bruce, Wellington, and other smaller units throughout the province were also treated with satisfactory results. Reports that came from all over Ontario showed that over 1,000,000 cattle, approximately one-third of the cattle population in the province, were treated in 1935 and 1936. Despite this promising start, interest and co-operation in the control of cattle grubs began to wane. The better farmers continued the work while others neglected to do their part. World War II then prevented the easy procurement of derris and cube root and the control of cattle grubs came almost to a standstill. Following the war, interest was again aroused in cattle grub control and some power spraying of cattle was done in townships in Huron and Bruce counties. Because of this interest, a committee was formed to in- vestigate all aspects of control by power spraying and to present recom- mendations. As a result of the work of this committee a control program was again initiated in the province in 1948. Enabling legislation was provided for the program under a revised Warble Fly Control Act to ensure against a possible revival on the part of some farmers of the apathy that had contributed toward the demise of the earlier ventures. The organization of the control campaign can briefly be stated as follows. On a petition of two-thirds of the cattle owners in a township a by-law must be passed bringing the Warble Fly Control Act into force. Under the Act all larvae in the backs of cattle in the township must be killed. If rotenone is used as the killing agent, the concentrations to be 235 applied by the spray or brush method and the time of application are specified. The Act is administered by the Ontario Livestock Commissioner and enforced by one or more inspectors appointed in each township. The townships are subsidized by the province to the extent of half the salary and expenses of the inspectors and half of the cost of the rotenone used. Although systemic insecticides may be used to kill cattle grubs, the costs of such treatment are not included in the subsidy. The control campaign has been well received by Ontario farmers as evidenced by the steady increase in the number of townships carrying on control programs under the Act. From 59 townships in 1950 (1), the program expanded to include 247 townships in 1955 (2) and 291 townships in 1960 (W. P. Watson, Ontario Livestock Commissioner, personal com- munication). Of the two million cattle in these townships eligible for treat- ment (two-thirds of the cattle population in Ontario,) approximately cne million head were infested and treated for the control of cattle grubs in 1960. Surveys have been conducted in some of the townships since 1948, the first year of the campaign, to measure the numbers of larvae in immature cattle. Table Il summarizes the report of the Ontario Warble Fly Com- mittee on the results of these surveys. With the exception of 1952 and 1954 there has been a steady decline in the numbers of larvae per animal. The period of 1952 to 1954 was one of rapid expansion of the control campaign and the survey. As a result, many townships were included in the survey for the first time in which high populations of larvae existed. TABLE II Numbers of cattle grubs in immature cattle of some Ontario townships from 1948 to 1958 Year No.townships AverageNo. Year No.townships Average No. surveyed larvae/animal surveyed larvae/animal 1948 12 1A 1953 66 3.3 1949 iL? 10.0 1954 90 3.6 1950 21 5.5 1955 101 2.0 1951 25 3.9 1956 — — 1952 A8 4.9 1957 97 0.8 1958 (03 , me) Although the control campaign has achieved considerable success in reducing the cattle grub population, the averaging of the numbers of larvae per animal in all of the townships hides a situation that has pre- vented the ultimate success of the campaign. In most of the townships involved in the control campaign, reduction in the numbers of larvae occurred after two or three years’ treatment. Subsequent control measures have been unable to lower the numbers further or to lower them at a greatly reduced rate. The surveys in several townships have shown slight increases after the initial rapid fall. The inability of control operations to further reduce the number of cattle grubs or to eradicate them in some areas may have several causes, the more likely being inefficient insecticide application techniques and faulty timing of insecticide treatments. The latter possibility was investigated by the writer (27). Based on the results of this study, it was suggested that the timing of insecticide treatments as stated in the Warble Fly Control Act were two to three weeks early for 236 maximum effectiveness. A subsequent modification has been made in the Act that partially conforms with the recommendations. It is still too early to assess the value of this modification. ~ DISCUSSION The reason for the apparent absence of a breeding population of H. lineatum in Ontario is rather surprising considering that the species was abundant in the province at one time. Large numbers of H. lineatum are known to be introduced into Ontario every year in feeder cattle originating from western Canada. Why the species cannot establish itself again is not known. Its absence is undoubtedly a great boon to cattle grub control in the province since additional rotenone treatments would have to be applied to control this earlier maturing species. Relatively accurate estimates of the losses attributable to cattle grubs and other insects are important. Their importance rests primarily in evaluating the pest as an economic force and thus determining the potential value that may be obtained by its control. The acquisition of such informa- tion has been very difficult. The only measurable injuries have been to hides and carcasses. Losses from other injuries produced by cattle grubs are largely unknown. Presumably earlier writers believed they were high, for much of their total estimated loss was a result of such injuries. The estimated loss of $5,000,000 proposed in Ontario in 1934 may be used as an example. The hide loss at this time was placed at $500,000. Carcass losses, based on the hide to carcass loss ratio in Table I, would not have ~ exceeded $1,000,000. It was probably much lower since attractive cuts of meat were of less importance then. In any case, at least $3,500,000 was attributable to other damage, primarily losses in productivity sustained as a result of gadding and the irritation caused by the larvae. On the basis of present knowledge of productivity losses, $3,500,000 was prob- ably far in excess of the actual loss sustained. Comparison of the estimated hide and carcass losses sustained in 1934 with those of 1958 affords an opportunity to assess the value of the control campaign in Ontario. Approximately 60,000 Ontario cattle poten- tially injured by cattle grubs were slaughtered each month, 50,000 in inspected establishments (2) and possibly 10,000 elsewhere. Again basing calculations on the data in Table I plus the monthly estimates of the per- centages of hides damaged (1), the hide and carcass losses from cattle grubs were about $150,000 in 1958. Thus, hide and carcass losses were reduced ten times between 1930 and 1958. It is probable that most, if not all, of this reduction was due to the control of cattle grubs in the province. Reports from Ontario farmers indicate that injury resulting from cattle gadding has almost ceased in the past several years. Low infestations of larvae in native cattle are probably causing negligible productivity losses. Thus, the total losses caused by cattle grubs in Ontario are probably not much in excess of the hide and carcass losses. The situation is rapidly approaching where the control of cattle grubs costs as much as the losses realized from these insects. The Ontario Live- stock Commissioner (mimeographed report) gave $70,000 as the prov- ince’s share of the costs of cattle grub treatment in 1959. Since costs are shared equally by the province and the townships involved, the total cost of eattle grub control in Ontario was $140,000. However, these costs could be greatly reduced. Cattle grub populations in many townships are now at such a low level that further reductions would result in large increases in the number of uninfested cattle that could be excluded from treatment. 237 Two possible reasons were advanced for the control campaigns’ in- ability to eradicate or reduce the number of larvae below a certain level in many townships. One of these was the timing of insecticide treatments which were shown to be in error. However, because of the low magnitude of the timing errors it is unlikely that their correction would fully solve the initial problem. The second reason, inefficient insecticide application, appears to afford a more valid explanation. It has been demonstrated repeatedly that success in the control of cattle grubs with solutions of rotenone applied either by a scrub brush or in a high pressure spray is related to the thoroughness of treatment. The efficiency of the spray method of application, by which the majority of infested cattle in Ontario are treated, is particularly vulnerable in this regard. In any case, the solution to the problem is greater precision in killing the larvae. The eradi- cation of cattle grubs from much of Ontario is potentially within our power. A big step toward this goal has already been taken and it would be unfortunate if the advantage were missed because of the lack of a little extra effort. ACKNOWLEDGEMENTS The author is indebted to W. P. Watson, Ontario Livestock Commis- sioner, Toronto, and W. C. Allan, Ontario Agricultural College, Guelph, for contributing information on the progress of the Ontario Warble Fly Control Campaign, and to the latter person, A. A. Kingscote and J. K. McGregor, Ontario Veterinary College, Guelph, eos gia reviewing the manuscript. REFERENCES , (1) BAKER, A. W., KINGSCOTE, A. A. and ALLAN, W. C. (1951). Warble fly control in Ontario. Rep. ent, Soc. Ont. 81: 76-80. 1950. (2) BAKER, A. W., KINGSCOTE, A. A. and ALLAN, W. C. (1956). Five years progress in the control of warble fly in Ontario. Rep. ent. Soc. Ont. 86: 41-45. 1955. (3) BIsHoPP, F. C., LAAKE, E, W., BRUNDRETT, H. M. and WELLS, R. W. (1926). The cattle grubs or ox warbles, their biologies and sugges- tions for control. Bull. U.S. Dept. Agr. 1369: 1-119. (4) CARPENTER, G. H., HEWITT, T. R. and KERRY REDDIN, T. (1914). The warble flies: Fourth report on experiments and observations as to life-history and treatment. 1. New facts in the life-history. Jour. Dept. Agr. Tech. Instruct. for Ireland, 15: 105-132. (5) GIBSON, A. and TWINN, C. R. (1936). Warble fly control in Canada. pel. Agr 172) 179-198: (6) HADWEN, S. (1912). Warble flies; the economic aspect and a con- tribution on the biology. Bull. Canada Dept. Agr. 16: 3-20. (7) HADWEN, S. (1915). Warble flies, a further contribution on the biology of Aypoderma lineatum and Hypoderma bovis. Foray 12,39 1-aoo) (8) HADWEN, S. (1919). Warble flies, Hypoderma lineatum Villers and Hypoderma bovis De Geer. Canada Dept. Agr. Sci. Ser. 27; 1-24. (9) HEARLE, E. (1932). Warble flies and their control in Canada. Pamph. Canada Dept. Agr. 147: 1-11, new series. (10) JAMES, M. T. (1947). The flies that cause myiasis in man. Mise. Publ: U:S) Dept; Agr. 6322 1-195," (11) JONES, C. M. (1959). Effects of Ronnel on control of cattle grubs and weight gains of beef cattle. J. econ. Ent. 52: 488-490. 238 (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) C3) (24) (25) (26) (27) (28) (29) (30) JONES, C. M. (1959). Cattle grub control with Ronnel. J. econ. Ent. G2 BZA ZO 2 KINGSCOTE, A. A. (1932). Local variations in the habits of the warble flies, Hypoderma bovis De Geer and Hypoderma lineatum Villers, together with notes upon experiments to produce artificial immunity and upon salt solutions as a larvicide. Rep. Ontario Vet. Coll., 1931, pp. 60-71. Ontario Dept. Agr. KINGSCOTE, A. A. (1957). Preliminary report on the use of systemic insecticide (Dow ET 57) in the control of warbles in cattle. (un- published). KNAPP, F. W., TERHAAR, C. J. and ROAN, C. C. (1958). Field studies with feed and bolus formulations of Dow ET-57 for control of cattle eruos.. hb. econ. Hint. 52%. 119-122: LOCHHEAD, W. (1916). Some notes regarding nose and other bot flies. Rep. ent. Soc. Ont. 46: 102-108. 1915. Market Information Section. (1960). Annual Livestock Market Review for 1959. Production and Marketing Branch, Canada Dept. Agr., Ottawa. Meat Packers Council of Canada. (1959). Lets be serious about warbles. A letter on Canadian Livestock Products, No. 2. Toronto. MorTE, D. C. (1928). The ox warble flies. Bull. Ohio Agr. Expt. Sta. LIS 1-45, NEEL, W. W. (1958). Field tests with systemic insecticides for the control of cattle grubs. J. econ. Ent, 51: 793-795. RICH, G. B. and IRELAND, H. R. (1959). Studies of bolus and feed formulations of two systemic insecticides for reduction of cattle warble infestations, (Oestridae: Diptera), in British Columbia, 1957-1958. Canad. J. Anim. Sci. 39: 170-175. RoGoFF, W. M. and KoHLer, P. H. (1959). Free-choice administra- tion of Ronnel in a mineral mixture for control of cattle grubs. J. econ. Ent. 52: 958-962. RoGoFF, W. M., KOHLER, P. H. and DuxBuRY, R. N. (1960). The im vivo activity of several systemic insecticides against cattle grubs in South Dakota. J. econ. Ent. 53: 183-187. SCHARFF, D. K. (1950). Cattle grubs: their biologies, their dis- tribution and experiments in their control. Tech. Bull. Montana Sta. Colle 277: 1-74. STEVENSON, L. (1934). The warble fhes. Bull. Ontario. Dept. Agr. 3002 1-11. STEVENSON, L. (1935). Warble fly control in Ontario. Rep. ent. Soc. Ont. 65: 81-83. 1934. TESKEY, H. J. (1957). Observations on the seasonal distribution of hypodermal larvae of the northern cattle grub, Hypoderma bovis (L.) (Diptera: Oestridae) at Guelph, Ontario, and their implications in control programs. Canad. J. Anim. Sci. 37: 114-120. TESKEY, H. J. (1960). Survey of insects affecting livestock in south- western Ontario. Canad. Ent. 92: 531-544. THURBER, H. E. and PETERSON, G. D. (1960). Feed lot tests with Ronnel for control of cattle grubs. J. econ. Ent. 53: 339-341. TURNER, E. C. and GAINES, J. A. (1958). Systemic insecticides for control of cattle grubs in Virginia. J. econ. Ent. 51: 582-585. (Accepted for publication: February 10, 1961) 239 THE HISTORY AND DEVELOPMENT OF THE EUROPEAN CORN BORER, OSTRINIA NUBILALIS (HBN.) (LEPIDOPTERA: PYRAUSTIDAE) AS AN ECONOMIC PEST IN ONTARIO’ H. B. WRESSELL The corn borer is still the most important insect pest of corn in Ontario, although today the severity of the damage i is lessened, so that it is no longer regarded as catastrophic, as it was in the decade 1920 to, L9S0: This article seeks to trace the development of the corn borer in Ontario, to show how it adapted itself to changing conditions, and to indicate its present status in the agricultural economy of the province. SYSTEMATIC HISTORY AND SYNONYMY For many years the corn borer was known to entomologists in Canada as Pyrausta nubilalis (Hbn.), a name that is still adhered to in the United States. Caffrey and Worthley (8) have an excellent short review on the synonymy of this insect. Apparently, during the 19th century, there was much confusion concerning its correct classification, but for over 60 years it remained in the genus Pyrausta, and seemed destined to stay there. But in 1957 a French worker, Marion, published a paper dealing with the family Pyraustidae in Europe. In it he set forth reasons why the corn borer should be placed in the genus Ostrinia (14). Dr. E. G. Munroe of the Entomology Research Institute, Ottawa, is in agreement with Marion. He stated (in litt.), “Ostrinia is a much older generic name pro- posed by Hubner on the basis of the Central European species palustralis. Marion considers these two species congeneric. I had independently reached the same conclusion in my own studies of the group, and I have no doubt he is right.” Dr. Munroe has advised research workers in Canada to adopt the name Ostrinia nubilalis (Hbn.) for the corn borer. EARLY HISTORY Vinal (24) first reported the presence of corn borer in North America. He discovered it in the vicinity of Boston, Mass., in 1917. However the borer was well known to corn growers near Port Stanley, Ontario, as early as 1910, but it was not reported officially until 1920 (13). The situation at Boston and in Elgin Country arose, apparently, as a result of importing broom corn from Hungary and Italy. In 1920 the borer was found in two widely-scattered places in southern Ontario. The first official recognition occurred on August 10 when scouts of the Entomological Branch, Ottawa, discovered an infested field at Lorraine Station, Humberstone Township, Welland County. A short while later the Port Stanley infestation was found; it proved to be much larger in extent than at first realized, and covered some 2,500 square miles (18). . During the period 1920 to 1928 the borer spread rapidly throughout southern Ontario, and could be found wherever corn was an important crop. Infestation was greatest in Essex and Kent Counties, where most of the husking or grain corn was grown. By 1927 corn acreage in these two counties was reduced by 75 per cent. According to Caesar (6) “Everyone except a few optimists now felt that the corn industry in these two coun- ties was probably doomed and that it was not wise to plant more than just a few acres per farm on the chance that something might turn up to iContribution No. 8, Entomology Laboratory, Research Branch, Canada Department of Agriculture, Chatham, Ontario, prepared at the invitation of the Publications Committee, Entomological Society of Ontario. Proc. ent. Soc. Ont. 91 (1960) 1961 240 destroy the borers’’, However Stirrett (19) has pointed out that the borer entered the seed-growing area of Ontario at a time when corn acreages were being reduced because of falling prices. At the same time there was a shift to a more intensive agriculture, as shown by increased plantings of tobacco and truck crops. Within the next few years a number of events occurred which did much to dispel the fears of corn growers. The Corn Borer Act came into force in the fall of 1926(7), but it was not adopted on a province-wide basis until 1927. Briefly stated this Act required farmers to suitably dispose of corn stubble before a prescribed date in the spring or suffer a penalty set by law. Farmers complied with the Act in various ways — some raked the stubble into windrows and destroyed the refuse by burning; others ploughed, the stalks under and laboriously handpicked the stubble brought to the surface by cultivation; a few used shredders, and some simply ignored the Act. On the whole co-operation was good, but the Act did mean that inspections were necessary for enforcement. During the first few years after the intro- duction of the Act there was a noticeable reduction in the corn borer population. Officials and growers both felt elated, and much credit was given to this form of control. But now it is evident that, while the clean-up, as it was called, undoubtedly helped in reducing the borer population, other factors were mainly responsible. Stirrett (19) conducted ecological studies from 1927 to 1936 and found that the borer is responsive to many different physical pressures which markedly affect oviposition and establishment. These will be dealt with under the ecology of the borer. Suffice it to state that Stirrett found that high temperature and low precipitation during June and July were associated with low infestation by the borer. Both Flint et al (11) and Davis (9) have written about the great influence exerted by drought in delaying the spread of the borer throughout the American Middle West. Davis stated that the season of 1934 definitely set the borer back several years. It would seem, in retrospect, that the weather was mainly respon- sible for reducing the borer population in the early 1930’s. Following these dry years there occurred another event that probably helped to keep the borer population down. This was the increase in acreage of hybrid corn in Ontario. Before 1938 only open-pollinated varieties were planted (22). To what degree hybrid corn helped reduce borer infestation is not known, but these varieties have a high degree of tolerance against the borer, and stalk breakage, even in a year of severe infestation, is greatly reduced (30). It was about 1938, too, that a noticeable change took place in the number of generations found each season, particularly in southwestern Ontario. The effect of this change and the probable reasons will be dealt with in another section of this review. HCOLOGY As mentioned above Stirrett (loc. cit.) conducted a 10-year environ- mental study of the corn borer with the assistance of many other workers in the field. The all-inclusive title is evidence of the scope of the study. The title reads ‘“‘A field study of the flight, oviposition and establishment periods in the life cycle of the European corn borer, Pyrausta nubilalis Hbn., and the physical factors affecting them.”’ Ecological studies were begun by H. G. Crawford near Union, Ont., in 1921. These were expanded in 1922 by G. J. Spencer and his assistants from the Ontario Agricultural College, while Crawford concerned himself mainly with cultural control (18). Spencer’s report includes many inter- esting details on the effect of external stimuli and physical factors on 241 different phases of borer life history, such as the effect of wind on direction and height of flight. He was concerned with all stages of borer development but dwelt at length on the habits of the larvae, He suggested that since newly-hatched larvae are prone to wander over the leaf a poisoned spray or dust might help to control them, especially in sweet corn — a suggestion that was overlooked for some years but is now part of standard control procedure. Some of his observations were of a casual nature, but they did point the way to Stirrett’s more detailed study at a later date. Stirrett’s ecological study (loc. cit.) is a classic of its kind, but only a brief review of this paper can be given here. One large section deals ex- haustively with the influence of physical factors upon flight. He concluded that the optimum temperature for flight lay between 65° F. and 70° F., and that flight is terminated when the temperature drops below 58° F. There is a positive correlation between temperature and moth flight even on individual nights, and no other weather factor regulates flight so markedly. “Average seasonal temperatures apparently have no regulative action on the duration of the flight season. The flight season was longest in the 2 years with the lowest average temperature, but in all other cases seasonal temperature did not affect the length of flight season. The shortest period did not occur in the hottest and driest season.” Although most moths flew at high humidities no correlation was found between moth flight and humidity on individual nights. During the period of study the highest wind velocity measured was only 17 m.p.h., which had no effect on flight. Heavy rains were found to prohibit flight, but moths flew in light rains. Lunar periodicity, atmospheric pressure, mists, fogs and cloudiness had not effect on flight. Stirrett pointed out that destruc- tion of eggs through dislodgement was caused by a series of alternate hot days and cold nights. This condition is conducive to heavy guttation which might help to loosen the egg masses. Hot, dry periods are not as important a factor in dislodgement of eggs. Stirrett also found that increased mor- tality is caused by sudden heat waves and is independent of humidity. Stirrett studied the quantitative flight of moths from year to year by means of a light trap. He found that “no relationship exists between the magnitude of flight in the corn field and that indicated by light trap catches.” He also found that the light trap is a better measure to determine seasonal limits of flight than in any individual corn field. During a few seasons a few moths were attracted to the light trap very late in the season; thus a fraction of one per cent of the population was thought to belong to a second generation. Earlier Crawford, Spencer and Caesar had found in some seasons a few mid-summer pupae. The general opinion, however, was that, as stated flatly by Stirrett, ‘““The insect as found in the area is of the univoltine type, as in western New York, Ohio, Michigan, Indiana and other midwestern states.’ The statement as it stands is per- fectly correct for that particular date (1938), but even as he wrote a change was taking place in southwestern Ontario, and the borer was developing from a single to a two-generation insect. First, however, a word must be mentioned about physiological ecology. This work was begun by Dr. W. E. Beckel at Chatham, Ontario, in 1956, and continued by J. A. Mutchmor. These workers were mainly interested in the factors affecting diapause in the corn borer (16). This was largely a laboratory study. They found that both temperature and photoperiod are important in inducing diapause, and “suggested that factors influenc- ing the early development of first-generation larvae will determine the proportion of borers completing development and contributing to the production of second flight.” 242 CHANGES IN THE STATUS OF THE BORER Ficht and Hienton (10), working in Indiana between 1935 and 1938, were the first to report that a definite change was taking place in the life history of the corn borer in the Great Lakes region. Shortly after this Vance (23) reported that the borer could be regarded as a two-generation insect in both Indiana and Ohio. Significant changes occurred in the life- history in southwestern Ontario in 1941 (4). These changes became more apparent in 1943 when Wishart (25), studying parasitism in Essex, recorded a definite increase in the number of pupae found during August — 2.5 per cent were found in 1941, as compared with 13.0 per cent in 1943. Wressell (28), working in the Chatham area, studied the flight of corn borer moths to a light trap located in the same place for twenty years. He found that from 1932 to 1951 the number of second-generation moths captured in the trap increased from less than two per cent to over 70 per cent. This change in voltinism manifested itself in other ways, such as a decrease in diapausing larvae at midsummer, and by the marked increase in damage to late canning corn. Formerly processing companies were able to avoid serious losses from borer damage by planting the crop late. The advent of the second generation changed this; as a consequence chemical control was practised on a greater scale than ever before, by both market growers and canning companies, A number of reasons have been given to explain this change in seasonal life history. Arbuthnot (1) has postulated that genetic factors are involved, and that there are two strains of borer. Ultimately the strains best suited to the environment will become predominent, but this may not occur for many years. Mutchmor (15) has proposed that the change from a one to a two-generation habit arose as a result of higher minimum spring temperatures, which in turn influence the number of larvae entering diapause at midsummer. A good review of this question has recently been presented by Beck and Hanec (5). In passing, a further note might be of interest. The writer has ex- posed larvae from three different sources to corn grown under caged conditions at Chatham, Ont. The original eggs came from Poughkeepsie, N.Y., where only multiple generation borers occur; Harrow, where the single and two generations occur; and from Ottawa, which is a single- generation borer. Borers from the Poughkeepsie source pupate seven to 10 days earlier in the spring than do borers from either of the other two sources, and moth emergence is correspondingly earlier. Harrow borers pupate slightly ahead of Ottawa stock. It would seem that environmental factors alone cannot be credited with the change in voltinism. METHODS OF CONTROL Biological Control : According to Baird (2) the first parasite laboratory in Ontario was established in St. Thomas in 1928. The laboratory was transferred to Chatham in 1925 because of the westward march of the corn borer, and stayed there until 1929, when the work was established at Belleville. Wishart (25), writing in 1942, stated that over a twenty-year period nearly 5,000,000 adult parasites of 17 distinct species and two additional races were liberated in an effort to combat the borer. Most of the releases were made in Ontario. Wishart stated that “no evidence appeared until 1940 to indicate a natural build-up of any species.” Although the initial establishment was usually good the parasite population diminished within a few years. By 1940, however, it was found that a species of Lydella was 243 present in large numbers along the Detroit River and near the shores of Lake Erie, particularly where a certain type of marsh existed. It was about this time that the second generation borer was beginning to develop, especially around La Salle where Lydella sp., while not plentiful, could be found. As Wishart points out the establishment of the parasites of the corn borer has been most successful in New England, where only the multiple generation occurs. In Ontario the second generation was first found at La Salle, and it is possible that this species of Lydella has become more common because of the increase of the second generation there. Among the parasites released in extreme southwestern Ontario, by officers of the Belleville laboratory, was Horogenes punctorius (Roman). This Ichneumonid was released in 1930 and in 1935, but no recoveries were made until 1957, when four pupae were found at three scattered locations in Essex County. In 1958 larvae in study plots at the Harrow Experimental Farm showed over 10 per cent parasitism by Hovrogenes. Wressell and Wishart (32) point out that this sudden appearance probably arose as a result of dispersal from Ohio, where this parasite has increased greatly in recent years. Another method of biological control used in Ontario has been the dissemination of fungous spores to plants. Using the fungus Beauveria bassiana Vuill. Stirrett et al (20) in 1936 and Beall et al (8) in 1938 showed that effective control by this means was possible in the field. Time of application was more important than rate, which applies equally to control by insecticides. The present writer has used Bacillus thurin- giensis as a microbial insecticide, but so far the results have not been outstanding. Chemical Control Tests with insecticides for corn borer control were made as early as 1931 in Ontario, but the insecticides then available gave poor results (21). It was not until 1941, when Stirrett and Thompson (loc. cit.) showed that rotenone and cryolite could be used under Ontario conditions, that serious considerations were given to insecticidal control of the borer, For several years rotenone was the recommended insecticide but it was never used extensively in Ontario, mainly because it was not readily obtainable during the war period of 1940-1946. When DDT became available for general use at the end of World War II it proved to be of inestimable value to table corn and canning corn growers. DDT and other insecticides of the hydrocarbon and phosphate groups were tested over a period of several years by Wressell (27), (29). It was found that several are useful against the borer. These include DDT, endrin, heptachlor, Dipterex, toxaphene and parathion. DDT is the standard insecticide because of availability, cheapness and ease of handling. Because of the residue problem, however, the hydrocarbons cannot be recommended if the corn stover is used as livestock feed, while parathion, because of its hazardous nature, should be applied only by a commercial operator. As long ago as 1945 Pepper and Carruth (17) had shown that the botanical insecticide, ryania, was useful in controlling the corn borer. Wressell (loc. cit.) found that it was comparable with DDT; so for many years it was the approved insecticide when the treated corn was used as livestock feed. It has not proved entirely satisfactory for several reasons. Ryania is not easy to obtain, it is relatively expensive and, because of the large amount needed for effective control, it clogs spraying equipment. Recently Sevin (1-naphthyl N-methylcarbamate) has shown promise in borer control. This material has been cleared for use by the U.S. Depart- 244 ment of Agriculture so that corn treated with it can used for fodder. If the claims made for it are substantiated in Canada it will be a useful addi- tion for borer control in Ontario. A number of insecticides are now available as granular formulations, and many of these have given excellent results against the borer, as demon- strated by Wressell and Driscoll (31). A granular insecticide is most use- ful when the young larvae have been overlooked and feeding has com- menced in the whorl! of the plant. This frequently occurs in husking corn grown for seed, where a single application of insecticide is all that is needed. Growers of market corn and canning corn processing companies usually resort to sprays or dusts. Spraying is the preferred method since it allows the toxicant to penetrate to the innermost part of the whorl, where the larvae eventually feed. The timing of insecticidal treatments is very important in corn borer control, and infestations frequently develop because growers overlook the simple but necessary procedure of examining plants for eggs (29). A study of varieties of corn resistant to the borer has been conducted for several years by the author, both at the Harrow Research Station and at the Central Experimental Farm, Ottawa. For the most part inbred varieties and single crosses have been under study, but occasionally the effect of borer infestation on double crosses has been observed. During the early part of this work the plants were exposed to only natural in- festation. Latterly, however, a given number of plants have been infested with a known number of eggs. This has afforded a better comparison of results. This is, of necessity, a long-term study. A Canadian inbred variety, CH., developed at the Harrow Research Station has given excellent promise of resistance to the borer. As a further check this inbred has been under study by U.S.D.A. entomologists at the Ohio Agricultural Experiment Station, Wooster, and at the European Corn Borer Research Station, Ankeny, Iowa. There is universal agreement as to the merit of this variety. Recombination tests are presently under way at Chatham. CONCLUSION During the 40 years that the corn borer has been known in Ontario it has passed through three distinct phases as an economic insect. During the first decade it was regarded as the most destructive pest that had ever invaded Ontario agriculture. Furthermore, it is assumed by Huber, et al (12) the original infestation in the American Corn Belt came from moths flying in from Ontario. The second period was one of quiescence. As a result of the different factors described in this review — climatic, the Corn Borer Act, the appearance of hybrid corn and, above all, the shift to multivoltinism, the corn borer was largely taken for granted during the second decade. By the mid-forties, however, because of the appearance of the second generation, the canning corn industry became more vulner- able to the borer, particularly in southwestern Ontario. As of today (1960) the industry is well equipped with spraying apparatus to cope with this pest, achieved, of course, at great expense. Many people have been engaged in the study of the corn borer in Ontario. Some, indeed, have reached high eminence in entomology and other professions. If I were to try to enumerate these workers it would read like an entomological Who’s Who of Ontario, if not Canada. The borer, however, is still with us, and it is likely to remain here for many years to come. 245 (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (16) (19) LITERATURE CITED ARBUTHNOT, K. D. (1944). Strains of the European corn borer in the United States. Tech. Bull U.S. Dept. Agr. 869. BAIRD, A. B. (1947). The entomological society and biological control of insects in Canada. Rept. ent. Soc. Ont. 77: 5-7. BEALL, G., STIRRETT, G. M. and CONNERS, I. L. (1939). A field ex- periment on the control of the European corn borer, Pyrausta nubilalis Hubn., by Beauveria bassiana Vuill. II. Sci. Aerie 9 - 531-534. BEALL, G. (1944). Multiple generation Pyrausta nubilalis Hubn. on plants other than corn in Ontario. Rep. ent. Soc. Ont. 74: 13-14. BECK, 8S. D. and HANEC, W. (1960). Diapause in the Eurepean corn borer, Pyrausta nubilalis (Hubn.). J. Ins. Physiol. 4: 304-318. CAESAR, L. (1929). The corn borer situation in Oniakina in 1928. Rep. ent. Soc. Ont. 59: 49-52. CAESAR, L. (1931). The European corn borer. Ont. Dept. Agr. Bull. 358. CAFFREY, D. J. and WORTHLEY, L. H. (1927). A progress report on the investigations of the European corn borer. U.S. Dept. Agr. Bull. 1476. DAVIS, J. J. (1935). The European corn borer: past, present and future. J. econ, Ent. 28: 324-333. FICHT, G. A. and HIENTON, T. E. (1939). Studies on the flight of - European corn borer moths to light traps: A progress report. J. econ. Ent. 32: 520-526. FLINT, W. P., HAYES, W..P., DUNCAN; G. H. and YounNGa esa: (1931). Drouth checks corn borer advance in 1930. Ill. Aer. Expt. Sta. Cares s6k: HUBER, L. L., NEISWANDER, C. R. and SALTER, R. M. (1928). The European corn borer and its environment. Ohio Agr. Expt. Sta. Bull. 429. MCLAINE, L. 8S. (1922). The spread of the European corn borer through southern Ontario. Rep. ent. Soc. Ont. 52: 26-28. MARION, H. (1957). Classification et nomenclature des Pyraustidae d’Europe. L’Entomologiste 13: 57-87 (not seen). MUTCHMOR, J. A. (1959). Some factors influencing the occurrence and size of the midsummer flight of the European corn borer, Ostrinia nubilalis (Hbn.) (Lepidoptera: Pyralidae), in southwestern Ontario. Canad. Ent. 91: 798-806. MUTCHMoOR, J. A. and BECKEL, W. E. (1959). Some factors affecting diapause in the European corn borer, Ostrinia nubilalis (Hbn.) (Lepidoptera: Pyralidae). Canad. J. Zool. 37: 161-168. PEPPER, B. P. and CARRUTH, L. A. (1945). A new plant insecticide for control of the European corn borer. J. econ. Ent. 38: 59-66. SPENCER, G. J. and CRAWFORD, H. G. (1923). Further notes on the life history of the European corn borer in Ontario. Rep. ent. Soc. Ont. 55 4 18-25- STIRRETT, G. M. (1938). A field study of the flight, oviposition and establishment periods in the life cycle of the European corn borer, Pyrausta nubilalis, Hbn., and the physical factors affecting them. pcr. Avr, 18? 565-683: 246 (20) STIRRETT, G. M. BEALL, G. and TIMONIN, M. (1937). A field ex (21) (23) (24) (25) (26) (27) (28) (29) (30) (31) (32) periment on the control of the European corn borer, Pyrausta nubilalis Hubn., by Beauveria bassiana Vuill. Sci. Agr. 17: 587-591. STIRRETT, G. M. and THOMPSON, R. W. (1941). Spraying for the control of the European corn borer in sweet corn. Rep. ent. Soc. Ont. 71:' 16-21. VANCE, A. M. (1939). Occurrence and responses of a partial second generation of the European corn borer in the Lake States. J. econ. Ent. 32: 83-90. VINAL, S. C. (1917). The European corn borer, Pyrausta nubilalis (Hbn.), a recently established pest in Massachusetts. Mass. Agr. Hxpuola Bull 178. WISHART, G. (1942). Important developments in the born borer parasite situation. Rep. ent. Soc. Ont. 73: 26-380. WISHART, G. (1947). Further observations on the changes taking place in the corn borer population in Western Ontario. Canad. Ent. 79: 8-838. WRESSELL, H. B., (1948). Further observations on insecticidal con- trol of the European corn borer, Pyrausta nubilalis (Hbn.), in southwestern Ontario in 1947. Rep. ent. Soc. Ont. 78: 10-14. WRESSELL, H. B. (1953). Increase of the multivoltine strain of the European corn borer, Pyrausta nubilalis (Hbn.) (Lepidoptera: Pyralidae), in southwestern Ontario. Rep. ent. Soc. Ont. 83: 43-47. WRESSELL, H. B. (1954). Control of the European corn borer in sweet corn. Canad. Dept. Agr. Publ. 909. WRESSELL, H. B. (1958). The history of the European corn borer, Pyrausta nubilalis (Hbn.) Lepidoptera: Pyralidae), in Canada. Proc. 10th Intern. Congr. Entomol. 3: 389-394. WRESSELL, H. B. and DRISCOLL, G. R. (1959). Granulated insecti- cides for control of the European corn borer in southwestern On- tario. J. econ. Ent. 52: 49-51. WRESSELL, H. B. and WISHART, G. (1959). Note on the occurrence of Horogenes punctorius (Roman) (Hymenoptera: Ichneumonidae), a parasite of the European corn borer, Ostrimia nubilalis (Hbn.) | (Lepidoptera: Pyralidae), in southwestern Ontario, Canad. Ent. 91: 579-580. | (Accepted for publication: March, 1, 1961) O SUMMARY OF IMPORTANT INSECT INFESTATIONS, OCCURRENCES, AND DAMAGE IN AGRICULTURAL AREAS OF CANADA IN 1960! C. GRAHAM MACNAY This summary of insect conditions in Canada in 1960 was prepared from regional reports submitted by officers of the Research Branch, provincial entomologists, and university professors. In general, common names used are from the 1960 revision of the list approved by the Entomological Society of America. To avoid unnecessary duplication, forest insect conditions are not included, this being adequately dealt with in the Annual Report of the Forest Insect and Disease Survey, published by the Forest Insect and Pathology Branch, Department of Forestry. 1Contribution No. 3 Scientific Information Section, Research Branch, Department of Agriculture, Ottawa, Canada. - Proc. ent. Soc. Ont. 91 (1960) 1961 247 GENERAL-FEEDING AND MISCELLANEOUS INSECTS BEET WEBWORM.—In Alberta the beet webworm was of minor importance, being less numerous than in 1959 and much less numerous than in 1958. In northeastern and eastern Saskatchewan, it severely damaged rapeseed crops, and stripped the leaves from flax after devouring the weeds. In Manitoba a severe outbreak occurred in flax fields, but the larvae fed mainly on mustard and weeds, then migrated in search of food and caused much damage to garden crops. CRICKETS. —In Saskatchewan a cricket, Nemobius griseus Wlk., occurred in large numbers on pasture land at Bjorkdale. Both the field cricket and the mormon cricket were more numerous than in many recent years, in western and southern areas of the Province. In Manitoba very large populations of the field cricket were of economic importance mainly in gardens, but they caused home owners great concern, both by their presence and by the emergence of innumerable parasitic mermithids from their dead bodies. In Ontario the field cricket caused considerable damage to ripening canning and garden tomatoes, and in eastern Quebec it became numerous late in the season. : CUTWORMS.—In British Columbia, cutworms were of minor economic impor- tance in the lower Fraser Valley. In the southern Okanagan Valley, the red-backed cutworm and the dark-sided cutworm were generally distributed. They fed on orchard cover crops and caused light to moderate damage to tomato, cucumber, melons, radish, and beets. In some orchards the spotted cutworm caused slight damage to buds and leaves on young apple, cherry, and peach. At Kamloops the red-backed cutworm moderately damaged garden crops and field plantings of asparagus and tomatoes. In the Peace River area it was less injurious than in 1959 and cutworm damage to alsike clover, barley, flax, and grass seed crops was moderate. Most noticeable was the damage to Merion blue grass by the glassy cutworm. Only one adult of the beet army- worm was taken in a light trap. In southern Alberta, damage by the pale western cutworm was considerably increased and occurred in widely separated fields, compared with negligible damage in 1959. A further increase in numbers was forecast for 1961. Damage by the red- backed cutworm was much less than in 1959 when it was extensive in parkland areas of the Province. A few severe infestations of the army cutworm damaged sugar beets at Bow Island and mustard at Warner and Milk River. Minor infestations of the bertha armyworm occurred on sugar beets at Iron Springs and on rapeseed at Strathmore. In Saskatchewan the red-backed cutworm caused light damage in only a few fields in the Saskatoon area, but it was more numerous than usual in city gardens. Elsewhere in northern and eastern areas, where 80,000 acres had been sprayed in 1959, it was not a pest of field crops. The pale western cutworm infested several thousand acres of cereal crops east of Saskatoon, most having been seeded on stubble. A small amount of crop was destroyed, but most was saved by spraying. Scattered, generally light infestations occurred throughout the prairie area of the Province. The armyworm moderately damaged several hundred acres of grain in Neidpath in southwestern Saskatchewan and at Moosomin. Huxoa detersa (Wlk.) caused some damage in sandy soil areas south of Floral. The bertha armyworm was very scarce and neither the army cutworm nor EHuxoa tristicula (Morr.) caused any reported damage. In Manitoba some 6,000 acres of sugar beets were sprayed for cutworm control, but in general no serious outbreaks occurred in the Province, probably because of a cold, wet spring. In southwestern Ontario various species of cutworms, mainly the black cutworm, required control measures to prevent serious damage in tobacco, sugar beets, onions, and various other crops. The variegated cutworm was less numerous than usual in tobacco crops. In western Essex County severe infestations of the fall armyworm on late canning corn required control measures, but other corn-infesting species were not as numerous as in previous years. In eastern Ontario cutworm damage to garden crops was about average and a survey revealed the armyworm to be quite scarce. In southwestern Quebec cutworms were unusually injurious to onions and lettuce. In eastern Quebec damage to garden crops, esecially transplants, was about average. Only a few adults of the armyworm were taken in light traps. In New Brunswick no cutworm damage to field crops was reported and damage in gardens varied from light to severe. The fall armyworm occurred on corn in much larger numbers than in 1959. No larvae of the armyworm were found in surveys, and very few adults were taken in light traps. In Nova Scotia the bronzed cutworm was present in small numbers in hayland in Kings, Lunenberg, and Halifax counties, and the dark-sided cutworm was abundant in Seles of Kings and Annapolis counties. No outbreaks of the armyworm were reported. In Prince Edward Island the variegated cutworm occurred in normal numbers and no reports of damage to grain by the armyworm or the red-backed cutworm were received. 248 In Newfoundland the black cutworm caused extensive damage to cabbage trans- plants in the St. John’s West area. EUROPEAN EARWIG.—In coastal areas of British Columbia the European earwig was very abundant in home gardens, and at Vernon in the interior it was common. In Alberta it had become established in Lethbridge and was spreading. In Ontario, records of establishment at Niagara Falls, Port Colborne, and Carleton Place indicated a notable spread southward and eastward of the main area of infestation. The occurrence at Carleton Place was the first known establishment in eastern Ontario. Earlier infestations at Montreal, Que., Yarmouth, N.S., and St. John’s, Nfld. continued to increase and spread. GRASSHOPPERS.—In British Columbia generally, grasshopper populations were at a low ebb. The little control necessary was carried out in the Nicola Central Zone and involved only about 1200 acres. Camnula pellucida (Scud.) occur in economic infestations in the East Kootenays, but was insignificant elsewhere. This applied in general also to Melanoplus bilituratus (Walk.). Melanoplus bivittatus (Say) was generally present, but light to moderate damage was reported only from the Taylor and Kersley areas. Melanoplus bruneri Scudd. compared with M. bivittatus in status. In increased only in the Chilcotin and Dragon Lake areas, but was not important. In southern Alberta, grasshoppers, especially C. pellucida, increased considerably in numbers. The most severe infestations were between Lethbridge and the foothills, and in the area west of Calgary. Smaller areas of severe infestation were scattered throughout southern Alberta. Must stripping and head cutting of grain occurred late in the season and in some areas hay, pasture, and fall-seeded crops were severely damaged. In Saskatchewan, cool spring weather delayed grasshopper hatching and pre- sumably reduced the outbreak, but fine weather followed hatching and persisted throughout the season. As a result a pronounced increase in the population occurred and it occupied about 50 per cent more territory than in 1959. The total area involved in some category of outbreak expectation for 1961 was about 1250 townships. C. pellucida was prevalent everywhere in the area and predominated west of the Third Meridian and north of the Qu’Appelle Valley. East of the Third Meridian and in the infested area south of the Qu’Appelle Valley M. bilituratus and M. bivittatus were also abundant. Species involved in minor outbreaks included Aeropedellus clavatus (Thos.) and Melanoplus confusus Scudd. Since about 1957 A. clavatus has been an important constituent of the population in native grasslands in widely scattered areas, notably at Lake Alma in the southeast and Tessier in the Saskatoon area. In 1960 a destruc- tive infestation occurred north of Abbey, affecting some 6,000 acres of pasture. Another species, Encoptolophus sordidus (Burm.), has been somewhat conspicuous during the current outbreak, although much less so than A. clavatus. In both 1959 and 1960 it was locally numerous in two separate areas near Abbey. The fungus Empusa grylli occurred fairly commonly, mainly on C. pellucida, but failed to prevent a major increase in the population. In Manitoba cool, wet weather delayed hatching. Infestations ranged from light to severe in the Red River Valley, the Carman-Graysville and Neepawa-Gladstone districts, and in the southwestern part of the Province. Marginal damage was common in the Red River Valley, late-sown crops being most affected. In the extreme south- west and in parts of the Red River Valley, much stripping and head-clipping occurred in flax. In the heavy soil areas of the Red River Valley, infestations were confined mainly to roadsides and alfalfa fields, M. bivittatus being the principal species and C. pellucida secondary. In pastures the order of these species was reversed and M. bilituratus was also present. The forecast for 1961 indicated a marked increase in the area affected and in the severity of infestation. In 1960 the Red River Valley was almost entirely infested. In Eastern Canada, where grasshoppers are normally of minor economic impor- tance, they were less numerous and injurious than usual in Quebec, and continued to be scarce in Prince Edward Island. JUNE BEETLES AND WHITE GRUBS.—In Saskatchewan, white grubs dam- aged potatoes at Meadow Lake, Nut Mountain, and Rosthern. In southwestern Ontario, contrary to expectations, white grubs were less injurious than in any corres- ponding period of their three-year cycle for at least 12 years. In the eastern area of the Province severe outbreaks occurred in a continuous band about 50 miles wide extending from Coboconk to Renfrew. Infestation was materially reduced in the area between Highway No. 7 and Lake Ontario and in the Ottawa Valley. In southwestern Quebec, adults were numerous and injurious to shade trees and ornamentals. In eastern Quebec damage to potatoes was moderate and in Nova Scotia it was negligible. In Prince Edward Island third-year larvae caused only minor damage to potatoes and strawberry transplants, but injury to lawns was severe in some areas, probably partly a result of damage by second-year larvae in 1959. 249 MEADOW SPITTLEBUG.—In coastal areas of British Columbia, spittlebugs were numerous on ornamentals and strawberries. In southwestern Ontario they were somewhat less numerous on alfalfa than in 1959. At Ottawa they occurred in slightly larger numbers on birdsfoot trefoil than on alfalfa or red clover. In eastern Quebec, populations were smaller than in 1959. SIX- SPOTTED LEAFHOPPER.—In Alberta and Saskatchewan, populations of the six-spotted leafhopper were small and damage slight. In Manitoba, spring migrants arrived in normal numbers, but the population failed to build up and the percentage of viruliferous leafhoppers was much lower than in 1958 and 1959. Consequently, there was less yellows than usual. In southwestern Ontario, migrants were few, if any. Both here and in southwestern Quebec, populations remained small and the incidence of aster yellows was low. From eastern Quebec eastward through the Atlantic Provinces, however, large numbers developed by September. In Quebec china asters were 100 per cent infected by yellows and losses in carrots ranged to 15 per cent. In Nova Scotia, damage, especially to carrots and lettuce, was the most severe in years. Most lettuce crops were a total loss and up to 96 per cent of carrots were infected. In Newfoundland the insect was numerous and moderately injurious. The severe outbreak and extensive damage in the Maritime area was believed to have been accentuated by very dry weather. WIREWORMS—In British Columbia, wireworm damage to potatoes was light for the second successive year in the Delta and Richmond areas. In most areas of the Prairie Provinces, too, damage was light to very light. In southern Alberta some thinning occurred in 40 per cent of the cereal stands, but it caused only four per cent reduction in the crop. In Saskatchewan, cereals, flax, and potatoes were injured at scattered points, but populations were smaller than in 1959 in all fields examined. Indications are that soil conditions during the past three years have been detrimental to both Ctenicera aeripennis destructor (Brown) and Hypolithus bicolor Esch. ‘ In the only infestation reported in Ontario, a field of soybeans in Kent County was moderately damaged by Limonius agonus (Say). In organic soil areas of southwestern Quebec, large wireworm populations, in- volving several species, occurred in neglected grassland. Onions and other crops in early stages of growth were also damaged. In the Ste. Martine area, Agriotes mancus (Say) destroyed the germinating seeds of sweet corn and from five to ten per cent of the young plants. In New Brunswick control materials were applied to some fields of potatoes where wireworm injury occurred in 1959. In Nova Scotia, populations of A. mancus and Hypolithus abbreviatus (Say) in the Annapolis Valley, and of Agriotes sputator (L.), A. obscurus (lL.), and A. lineatus (L.) in Cape Breton, Halifax, Lunenburg, Yarmouth, and Digby counties, were normal. In Prince Edward Island Limonius pectoralis Lec. was numerous in potato fields in the extreme western part of the Province, and occurred in two fields near Charlottetown. In Newfoundland A. lineatus extensively damaged lettuce plantings in the Goulds area and rutabagas at Kilbride. FIELD CROP INSECTS APHIDS.—In the lower Fraser Valley, B.C., Macrosiphum avenae (Fab.) and Metapolophium dirhodum (Walk.) occurred on cereal crops in normal numbers, but Rhopalosiphum padi (L.) was present in very small numbers. The pea aphid occurred early on peas, but was generally controlled. In the Prairie Provinces the corn leaf aphid occurred in widely scattered infesta- tions on barley. Losses generally were light except in parts of Manitoba, where damage was accentuated by heat and drought. In Saskatchewan the potato aphid was numerous on flax in some areas; the English grain aphid was abundant on wheat and oats; the turnip aphid occurred on rape; and R. padi was present on oats. How- ever, no crop losses were reported. In southwestern Ontario the pea aphid was numerous on alfalfa in Kent and Essex counties, but the corn leaf aphid infested corn in only a few fields. At Ottawa, specimens of the English grain aphid and the green peach aphid trapped early in May were believed to have been carried to the area by southerly winds. In southwestern Quebec the pea aphid population on canning peas and clovers was generally light. In eastern Quebec, numbers of this species were large on clovers, causing spotty damage, and the corn leaf aphid caused minor damage to barley. In the Atlantic Provinces the English grain aphid was generally numerous, requiring control measures in some grain fields in Nova Scotia, but damage was comparatively light. BARLEY JOINTWORM.—In the infested area of Prince Edward Island, this insect was not a serious pest in 1960. 250 CLOVER-INFESTING WEEVILS.—In the Milk River Valley, Alta., peak larval populations of the alfalfa weevil rose from an average of 156 per net sweep in 1959 to 263 in 1960, and damage was evident for the first time in the Province. In irrigated alfalfa in southwestern Saskatchewan, populations were smaller than in 1959 and much smaller than in 1958. In southern Alberta the sweetclover weevil was less abundant than in 1959, and in eastern Ontario it was common, but not a serious pest. At Ottawa, Ont., the clover head weevil was scarce in red clover. In eastern Quebec the lesser clover leaf weevil, the clover root curculio, and a clover seed weevil, Tychius picirostris (F.), were numerous, and an alfalfa weevil, Sitona scissifrons ‘Say, occur- red in moderate numbers on forage crops. In Newfoundland the lesser clover leaf weevil severely damaged the leaf and flower buds of red clover. CLOVER SEED CHALCIDS.—At Ottawa, Ont., populations of the clover seed chaleid, Bruchophagus gibbus (Boh.), in red: clover, averaged about one per net sweep. A seed chalcid, probably B. kolobovae Fed., was reared from birdsfoot trefoil, the first record of a chalcid in the seed of this host in the Ottawa area. CLOVER SEED MIDGE.—Populations of this midge were about normal in the Ottawa area, but at L’Original, Ont., it caused about 50 per cent loss in one field. In eastern Quebec it was numerous and injurious on red clover. CORN EARWORM.—This insect was not recorded in Saskatchewan for the fifth consecutive year. In southwestern Ontario it was generally abundant and in outbreak numbers in Essex County, severely damaging late canning corn. In southwestern Quebec it was very scarce in sweet corn. In New Brunswick, damage to mid-season and late corn was the most severe since 1947. In Prince Edward Island the insect was not recorded. DIAMONDBACK MOTH.—In southern Alberta the diamondback moth occurred in large numbers on mustard. In Saskatchewan it attacked almost all rape crops, causing an overall loss of 15 to 20 per cent in yield, and a further loss from dockage because of small seed. Approximately 100,000 acres of rape were sprayed. In Manitoba extensive damage was accentuated by hot, dry weather. EUROPEAN CORN BORER.—In the infestation area of southeastern Saskat- chewan, the European corn borer was much more numerous and injurious than in 1959. In southwestern Ontario, infestation was very spotty. Much corn was seeded late and escaped heavy infestation. However, canning corn in Essex County was severely infested, especially by second-generation larvae. Corn in Kent County was less severely attacked. The greatest damage to grain corn occurred in Middlesex County, infestation in one field amounting to 91 per cent of the plants. The average plant infestation in the five southwestern counties was 25 per cent, the same as in 1959, but the total borer population. was much smaller. In eastern Ontario a significant increase in the borer population in garden corn occurred in Prince Edward, Hastings, and Northumberland counties. In southwestern Quebec, infestation of sweet corn in the canning areas was light. A survey at harvest revealed an average of 3.8 per cent ear damage, and an average of 2.7 borers per 100 ears. In the Montreal area a survey at canning factories revealed 18 per cent ear infestation. In New Brunswick, infesta- tion was general but very light. FLAX BOLLWORM.—Although less abundant than in 1959, the flax bollworm caused five per cent loss in the flax yield in western Saskatchewan. Infestation was general, ranging from a trace to 14 per cent. The spraying of several thousand acres of crop prevented more serious losses. FLEA BEETLES.—In southern Alberta Phyllotreta spp. damaged mustard. In Saskatchewan they infested rape at Watson, Yorkton, Canora, and Hudson Bay, and control measures were necessary in some areas. In Manitoba large populations occurred on rape in the Boissevain, Morden, and Hamiota areas, and damage was accentuated by heat and drought. In eastern Quebec the hop flea beetle was abundant on forage crops in May and June. LEGUME-POLLINATING BEES.—In the Wanless area of northern. Manitoba, the leaf-cutter bees Megachile frigida Sm. and M. inermis Prov. were about twice as numerous on alfalfa as in 1959, but the population of the bumble bee Bombus terricola Kby. was about half that of 1959. NORTHERN CORN ROOTWORM:—In recent years the northern corn rootworm has become fairly abundant in parts of Essex County, Ont., where successive crops of corn have been grown, and in 1960 some injury occurred in several areas. PLANT BUGS.—In British Columbia Liocoris spp. were injurious to alfalfa seed crops in the Peace River district. In the Okanagan Valley they were less injurious than in 1959 and no major damage was reported. In northern Saskatchewan, plant bugs, especially Liocoris unctuosus Kelton and L. borealis Kelton, occurred in injurious numbers in every alfalfa field sampled. As in 1959, populations averaged about 10 bugs per net sweep and control measures were necessary in some fields. Much smaller numbers occurred in red clover. Very few major infestations of Adelphocoris lineolatus (Goeze) occurred on alfalfa, mainly because of spring burning, but in a few neglected 251 fields, populations were the largest ever recorded in the Province. Only small popula- tions occurred in old stands of red clover, Plagiognathus medicagus Arrand was not numerous in alfalfa, but record numbers developed in red clover. At Ottawa, Ont., A. lineolatus occurred in normal numbers in alfalfa and birdsfoot trefoil. Normal populations of Plagiognathus chrysanthemi (Wolff) occurred in alfalfa and red clover, but, in 1960 as in 1959, exceedingly severe, local outbreaks caused much damage in seed crops of birdsfoot trefoil. As in 1959, populations of the tarnished plant bug were below normal in most clover fields. In eastern Quebec, both the tarnished plant bug and P. chrysanthemi were very abundant in alfalfa and clover fields. RED TURNIP BEETLE. — This insect fed on cruciferae in the Peace River, B.C., district, and at Fort Vermilion, Alta. In Saskatchewan it damaged rape at Hudson Bay and Wilkie, and cultivated mustard at St. Gregor. ROOT MAGGOTS. — For the third successive year, the root maggot complex, Hylemya cilicrura (Rond.) and H. liturata (Mg.), attacked flue-cured tobacco in southwestern Ontario in greater numbers and in a larger area than in each preceding year. In Norfolk County, corn seed treated with chlorinated hydrocarbons was severely injured. Damage in both cases was attributed to the development of resistance in the root maggots to certain insecticides. A progressive increase has occurred also in the numbers of Euxesta notata (Wied.). A EUROPEAN SKIPPER, Adopaea lineola Ochs. — Although adults of this skipper were abundant in the area of infestation east of Georgian Bay and Lake Huron, grass grew rapidly while the larvae were developing and damage was light. SUGAR BEET INSECTS.—In southern Alberta the sugar-beet root aphid was present in all sugar beet growing districts, but severe damage occurred only locally. Many aphids were destroyed by predators, both in beet fields and in poplar galls before the aphids migrated to beets. Damage by Silpha bituberosa Lec. was negligible. In southern Alberta, damage to beets by flea beetles was light. In Manitoba almost 5,000 acres of sugar beets were treated to control the sugar-beet root maggot. In southwestern Ontario the sugar-beet root aphid was scarce in spite of dry weather. THRIPS.—In the Peace River, B.C. area, Haplothrips leucanthemi (Schrank)’ heavily infested red clover seed crops, but damage of economic imortance was not evident. In Saskatchewan somewhat similar conditions were reported. SUNFLOWER INSECTS.—In Manitoba, insect damage to sunflowers generally was very light. Infestation by the banded sunflower moth was very light, as in 1959, with about 0.5 per cent seed damage reported. No specimens of the sunflower moth were noted. Infestation by the sunflower beetle continued to decline from the high of 1958 to a point where it was sporadic rather than general. The painted lady was present in very small numbers and no larval damage was noted. Isolated cases of severe cutworm damage were reported, but generally there was less damage than in 1959. The weevil Rhynchites aeneus (Boh.) was more abundant than usual with two to three per cent head drop noted in some fields. The six-spotted leafhopper was less abundant than in 1959 and little aster yellows occurred on sunflowers. TOBACCO INSECTS.—In southwestern Ontario, populations of the tomato horn- worm and the tobacco hornworm on tobacco were the largest in five years and parasitism by Apanteles sp. was very light..The green peach aphid occurred in only a few isolated infestations. A stink bug, Huschistus sp., severely infested a field of tobacco in Elgin County, and the three-lined potato beetle, in an unusual infestation, severely injured a planting in Bruce County. Insecticide-resistant strains of root maggots were injurious for the third successive year (see ‘Root Maggots”). In Nova Scotia the tomato hornworm occurred in small numbers on tobacco in Kings County. A WEBWORM, Cnephasia virgaureana Treit. — This recently introduced pest caused considerable defoliation of red clover in Newfoundland. WHEAT INSECTS.—In the Kersley area of central British Columbia, the wheat midge severely damaged wheat in several fields. In Alberta, severe damage by the wheat stem sawfly was found only in a small area southeast of Lethbridge. In southwestern Ontario the European wheat stem sawfly was much less numerous than usual, probably because of extensive winter killing of wheat in 1959. VEGETABLE INSECTS APHIDS.—In the lower Fraser Valley, B.C., the green peach aphid event in large numbers on potato. Leafroll virus spread rapidly and some tuber damage occurred in late potatoes. In the Okanagan Valley, infestation was fairly heavy, but at Kamloops it was much lighter than in 1959. In both districts there was less leafroll than in 1959. In the lower Fraser Valley, Cavariella konot Takahashi (prev. C. 2The thrips in red clover recently called Haplothrips niger (Osb.) was put back to H. leucanthemi (Schrank). L. J. Stannard Jr. 1957. Phylogeny and classification of the North America Genera of the Suborder Tubulifera (Thysanoptera). Illinois Biological Monographs No. 25, p. 52. 252 archangelicae in Canada) was injurious to celery; Myzus ascalonicus Donec. was unimportant on its hosts; and the cabbage aphid was fairly numerous, except in coastal areas, where it was scarce. In Saskatchewan, aphid damage generally was negligible. The potato aphid appeared generally on flax but was not a pest on potatoes, and the turnip aphid caused some damage to turnips at Estevan. In Ontario normal numbers of the pea aphid caused light damage to legumes. In eastern Quebec the potato aphid required control measures on potato in some areas, but other species were unimportant. In New Brunswick the green peach aphid was only one-third as numerous on potato as in 1959. Aphis nasturti KItb., usually spotty in distribution, increased tremendously in numbers and was generally distri- buted; potatoes in check plots were destroyed by the end of August. The pea aphid was numerous in Carleton and Sunbury counties, and the cabbage aphid was scarce on cabbage and broccoli in the Maugerville area. In Nova Scotia, aphids were more numerous than usual on potato, but were eventually controlled by parasites. In the Annapolis Valley the pea aphid heavily infested peas, and the cabbage aphid was more numerous than usual on cabbage and turnip. In Prince Edward Island, potato aphids, mainly Macrosiphum euphorbiae (Thomas), were generally more numerous than usual, but other aphid species were scarce. ASPARAGUS BEETLES. — The asparagus beetle and the spotted asparagus beetle appeared early on asparagus in southwestern Ontario and control measures were necessary. In eastern Ontario the latter species was common and the former scarce. BLACK SWALLOWTAIL.—From Quebec eastward to Nova Scotia, this insect was more numerous than usual on carrot, celery, parsley, and dill. Some damage was caused, notably in the Lincoln, N.B., area, where the loss in one field. of dill amounted to over 30 per cent. CARROT RUST FLY.—In the lower Fraser Valley, B.C., this insect was very scarce. In Ontario, damage was slightly greater than in 1959 in a few areas, but surprisingly decreased generally from that of a few years ago. In eastern Quebec and Nova Scotia, damage was normal, but in New Brunswick it was very light. In Prince Edward Island, damage was moderate to severe in home gardens and light in commer- cial plantings. In Newfoundland the insect was conspicuous by its absence. CARROT WEEVIL.—In the Bradford Marsh, Ont., the carrot weevil remained confined to a small area. CATERPILLARS ON CRUCIFERS.—The diamondback moth occurred in normal abundance in southwestern British Columbia, and in light infestations in central and northern areas of the Province. In Saskatchewan, five to ten per cent of cabbage and cauliflower were damaged in the Saskatoon-North Battleford-Prince Albert area. In Ontario the insect was scarce in the southwest, but about twice as numerous as usual in the Ottawa area, where it caused severe damage to cauliflower, cabbage, and rutabagas. In Quebec early cabbage and cauliflower were severely damaged. In New Brunswick, brussels sprouts was extensively attacked and other crucifers to a lesser degree. In Nova Scotia, populations were normally large on cabbage and turnip. In Prince Edward Island, damage was lighter than in 1959, but was moderate in some crops. In Newfoundland unusually large populations caused moderate to severe damage throughout the Province. The imported cabbageworm was generally distributed and normally injurious in British Columbia. In Saskatchewan it occurred in reduced numbers. In Ontario, populations were generally large, and at Ottawa were larger than in any other year since 1952. In Quebec, too, damage was extensive, although in the vicinity of Quebec City the population was greatly reduced by a virus disease. In New Brunswick, damage was light to moderate. In Nova Scotia, cabbage was heavily infested, and in Prince Edward Island rutabagas and other cole crops were severely attacked. In Newfound- land, populations were larger than in 1959, but well below outbreak proportions. The cabbage looper was numerous and injurious in southwestern Ontario, and slightly below average in the Ottawa area. It occurred generally in the Atlantic Provinces, but caused little damage. The purple-backed cabbageworm was reported from Cape Breton, Richmond, and Guysborough counties in Nova Scotia. In Newfoundland it was more numerous than usual and severely defoliated swede turnips in eastern districts. COLORADO POTATO BEETLE. — In Saskatchewan the Colorado potato beetle occurred in spotty infestations in south-central areas, and in the area bounded by Saskatoon, St. Louis, and Rosthern. In Ontario and Quebec, populations were generally small and damage was light to moderate. In New Brunswick and Nova Scotia, numbers varied from small to normal, but in Prince Edward Island, populations were large in some localized areas. CUCUMBER BEETLES.—tThe striped cucumber beetle occurred only in small numbers in New Brunswick, and in Prince Edward Island it had not been recorded for several years. 253 FLEA BEETLES.—tThe potato flea beetle damaged potatoes slightly at Estevan, Sask. In Ontario and Quebec it was numerous and injurious to potatoes. In some areas tubers were damaged by larvae of the second generation. In New Brunswick the flight of second-generation adults was one of the largest on record. In both Nova Scotia and Prince Edward Island, populations were larger than in 1959 and some tuber damage occurred. Extra control measures were required in most of Eastern Canada. In southwestern British Columbia the tuber flea beetle occurred early and in large numbers and in the southern interior infestation was average. In both areas severe damage occurred where potatoes were inadequately sprayed. In Saskatchewan Phyllo- treta spp. damaged rutabagas slightly at Saskatoon and Estevn. In the Ottawa River Valley, populations of P. cruciferae (Goeze) on crucifers declined for the second successive year, and were the smallest since the species was first recorded in eastern Canada in 1954. In Quebec, Phyllotreta spp. caused severe damage to various hosts. HORNWORMS.—At Westbank in the Okanagan Valley, B.C., populations of the tomato hornworm were the largest in several years, but damage to tomatoes was not serious. Damage by hornworms, probably this species, occurred also at Dawson Creek, B.C. In southwestern Ontario, populations of Phlegethontius spp. were the largest in several years. In the Atlantic Provinces the tomato hornworm was scarce. LEAFHOPPERS.—In southwestern Ontario the potato leafhopper occurred in greatly reduced numbers, probably because of cold, wet weather in early summer. Damage to potatoes was greatly reduced. MEXICAN BEAN BEETLE. — In the Huron-Lambton area of infestation in Ontario, the Mexican bean beetle was more injurious to beans than for several years. In Quebec, 2.3 per cent of 42 fields of beans inspected in the Montreal area were found to be infested, and small numbers of the beetle occurred near St. Chrysostome, Frank- lin, and Ste. Clothilde. In New Brunswick a small infestation occurred in a garden near Fredericton. NUTTALL BLISTER BEETLE.—Within a fairly large area around Saskatoon, this beetle attacked beans, lettuce, spinach, turnips, and caragana. Broad beans especially were damaged. MITES.—At Kelowna, B.C., spotty infestations of the brown wheat mite occurred on spring onions and were severe where irrigation was neglected. The two-spotted ae mite was a problem on vegetables at Prince George, B.C., and on cucumber in uebec. ONION MAGGOT.—In the. southern interior of British Columbia, infestation of onions by the onion maggot was about average. In Saskatchewan, damage was less than in 1959. In Ontario, populations were greatly reduced and damage was negligible. An outbreak of Empusa muscae Cohn in 1959 and 1960, in conjunction with extensive spraying, was considered responsible for the situation. In Quebec, onion plant mortality in the early part of the season amounted to 25 to 95 per cent in untreated plantings, and maggot strains resistant to chlorinated hydrocarbons were common in the Montreal area. However, as in Ontario, the infestation was reduced by EF. muscae, dry weather, and effective control measures, and an excellent crop of late onions was harvested. In the Fredericton, N.B., area, damage was severe in home gardens, but in Prince Edward Island damage during the season was light. PEA MOTH.—In both New Brunswick and Prince Edward Island, infestation by the pea moth was severe in many home gardens, but in commercial plantings the insect was well controlled. PEPPER MAGGOT.—In Essex County, Ont., this maggot again infested sweet peppers and was believed to have damaged eggplant. PLANT BUGS.—An unidentified mirid damaged cabbage noticeably at Kamloops, B.C. The four-lined plant bug caused minor damage to garden crops in eastern Quebec. The tarnished plant bug was abundant on clover, alfalfa, and potatoes in eastern Quebec. It was numerous in New Brunswick, more numerous than usual in Nova Scotia, and present in large numbers in Prince Edward Island. ROOT MAGGOTS IN CRUCIFERS.—In British Columbia the cabbage maggot was the major root maggot pest of turnips at Kamloops and Kelowna, and of rutabagas near Victoria. Other species damaging turnips on the mainland included the seed-corn maggot and the onion bulb fly. At Prince George and Quesnel the turnip maggot and the seed-corn maggot severely damaged turnips. In northern Alberta the cabbage maggot caused damage ranging up to 90 per cent in susceptible garden crops. In Saskatchewan both the turnip maggot and Hylemya planipalpis (Stein) were even less injurious than in 1959. In most of Ontario the cabbage maggot was less injurious than usual. At Ottawa, oviposition on cabbage was only 72 per cent of the long term (12 year) average. In untreated radish only 39 per cent of the roots were unmarket- able, compared with 80 per cent in 1957, 74 per cent in 1958, and 62 per cent in 1959. In Quebec this species was, as usual, a major pest of crucifers. In New Brunswick it was scarce, probably because of dry weather. Cabbage and cauliflower were lightly 254 attacked, but turnips and rutabagas were somewhat more heavily infested. In Prince Edward Island the cabbage maggot appeared early and damage was severe on early crucifers, some fields of rutabagas being unmarketable. In late plantings, infestation was light to moderate, mainly because of hot, dry weather in the growing season. In Newfoundland, populations were unusually large and damage was severe, especially in cabbage and swede turnips along the west coast. RED TURNIP BEETLE.—In Saskatchewan this beetle caused moderate damage to cole crops in an area bounded by Saskatoon, Watson, and Meadow Lake. ~ SEED-CORN MAGGOT.—In Saskatchewan no damage by this insect was reported. In Ontario it fed extensively on potato seed pieces in Elgin County, and damaged tomato transplants and treated cucurbit seed in Norfolk County. In Quebec and Nova Scotia it caused heavy losses in untreated field beans. In Prince Edward Island it was not an important pest. SLUGS.—In the lower Fraser Valley, B.C., Arion circumscriptus (Johns.) damaged clovers, ornamentals, and truck crops, especially lettuce. In the Vernon district the spotted garden slug was injurious to garden crops. At Edmonton, Alta., and Winnipeg, Man., slug damage occurred commonly in gardens. In southwestern Ontario Deroceras sp., possibly agreste (Linné), damaged garden crops, strawberries, and field corn. In the Nicolet, Que., area slugs were troublesome. In Prince Edward Island damage was mainly confined to flower gardens, and in Newfoundland early season damage occurred, but it was less than in 1959. SQUASH BUG.—This pest of curcubits occurred commonly in Hastings and Prince Edward counties in Ontario, where it previously had been scarce. STEM BORERS.—In Quebec the stalk borer commonly damaged rhubarb, and the potato stem borer was a minor pest of potatoes and rhubarb. In Nova Scotia the latter species caused some damage, but was less numerous than usual. A SYMPHLID.—The symphylid first reported in 1959 attacking beets, lettuce, and cabbage on Vancouver Island has been identified as the garden symphylan, Scutigerella immaculata (Newport). During 1960 it occurred as far north as Courtenay, on the southwest coast at Sooke, and in several areas in the Keating district, damaging strawberry and potato crops. In Washington and Oregon, U.S.A., this pest causes extensive damage to vine, cole, strawberry, and many other crops and is difficult to control. THRIPS.—In southwestern Ontario, populations on onions were about normal, and damage to cabbage was minor. FRUIT INSECTS APHIDS.—In the interior of British Columbia Aphis pomi DeG. continued to be a troublesome pest in apple orchards, especially on young trees. In Ontario, aphids were not a serious problem on fruit trees, although in Norfolk County A. pomi persisted later in the season than usual. In Quebec this species was less numerous than in 1958 and 1959, and infestation ranged from light to medium. In New Brunswick it was generally numerous. In Nova Scotia it was present in small numbers in the spring and the dry season kept populations small. The fungus Empusa sp. was a major control factor in some orchards. For the second successive year, in the interior of British Columbia, the rosy apple aphid occurred fairly com- monly in commercial apple orchards. For several years prior to 1959 it was a pest only in abandoned orchards. In New Brunswick a general increase in fruit damage occurred. In Nova Scotia aphid injury to apples was light, but slightly greater than the exceptionally small amount that occurred in 1959. The injury was caused almost entirely by the rosy apple aphid. A fall survey indicated that populations would be small again in 1961. In both British Columbia and Nova Scotia, Hvriosoma lanigerum (Hausm.) remained scarce, and Rhopalosiphum spp. occurred in normal numbers in the latter province. In British Columbia the green peach aphid was numerous on peach early in the season; the black cherry aphid was less injurious than in 1959; and the thistle aphid and mealy plum aphid were easily controlled in many prune and apricot orchards. APPLE (AND BLUEBERRY) MAGGOT.—In Ontario there was a marked general increase in damage to apples by this pest, and it also attacked prunes freely in the Niagara Peninsula. The increase in the percentage of infested fruit was attri- buted to a light crop of apples and an unusually prolonged period of fly emergence. In Quebec, New Brunswick, and Nova Scotia a general increase in damage recorded in 1959 continued in 1960, and losses were extensive where sprays were poorly timed. In Prince Edward Island some severe damage occurred, but populations were reported to be slightly smaller than in 1959. APPLE MEALYBUG.—In both New Brunswick and Nova Scotia small popula- tions of this mealybug caused little damage. APPLE SEED CHALCID.—tThis pest was generally distributed in New Bruns- wick and Nova Scotia, and heavily infested neglected apple trees. 255 APPLE SUCKER.—Nymphs of the apple sucker were moderately abundant in many ochards in Nova Scotia. — BLUEBERRY PESTS.—The blueberry maggot, Rhagoletis pomonella (Walsh), increased generally in New Brunswick, especially in Charlotte County. In Nova Scotia it was well controlled, and in Prince Edward Island damage was light. In both New Brunswick and Nova Scotia, cutworms generally caused little damage, although the black army cutworm was locally numerous in an area in Kent County, N.B., and caused early season damage to blueberry shoots at Sutherland’s Lake, N.S. In Nova Scotia a leaf beetle, Galerucella vaccinu Fall, caused minor foliage injury in northern and eastern areas. Large numbers of the blueberry flea beetle Altica sylvia Mall. caused considerable defoliation in approximately the same area later in the season. (See also “Thrips’’.) BUD MOTHS.—In the interior of British Columbia the eye-spotted bud moth continued to be of minor importance. In Ontario it increased in the Norfolk County, Georgian Bay, and eastern Ontario areas, but few infestations were severe. In Quebec it was difficult to control and injury was more common than usual. In New Brunswick, generally, infestation was light, but at harvest time considerable damage was ob- served in a few orchards. In Nova Scotia, after several years of very light infesta- tion, definite increases in numbers were observed in 1950 and 1960, but control measures were nowhere necessary. In Prince Edward Island moderate damage occurred in neglected orchards. In Nova Scotia the green budworm, Hedia variegana (Hbn.), was a little more numerous than usual. CANKERWORMS.—In Nova Scotia the fall cankerworm caused some damage in Kings County, but was less numerous than in several previous years. The winter moth, in its usual numbers, was more generally distributed and caused more damage than the fall cankerworm. CASEBEARERS.—In Nova Scotia, casebearers decreased in some orchards and increased in others. The pistol casebearer was abundant than the cigar casebearer. CHERRY FRUIT FLIES.—In British Columbia the black cherry fruit fly had not been recorded in the Okanagan Valley since 1953, and was not reported in the Kootenay Valley. A CHERRY MIDGE.—In Quebee a midge, Contarinia virginianae Felt, was injurious to wild and cultivated cherries, and was difficult to control in the Rouge- mont area. In eastern Quebec increased numbers and new infestations were reported. CODLING MOTH.—In the interior of British Columbia, cool weather retarded development and the codling moth was less injurious than in 1959. In Ontario, too, cool weather delayed development of both the first and second generations and no serious infestations occurred in commercial apple orchards. However, in the Niagara Peninsula, Bartlett pears were severely infested in a few orchards. In southwestern Quebec the insect was less abundant than in several previous years, but was still an important pest of apple. In New Brunswick, infestation was heavy only in a few orchards. In Nova Scotia, populations generally compared with those of 1959, when they were the smallest in at least twenty years, but increases occurred in a few orchards. In Prince Edward Island damage was very slight. CRANBERRY PESTS.—In Nova Scotia the cranberry fruitworm caused up to 70 per cent loss of fruit in some bogs. In Prince Edward Island it caused slight damage in localized areas. In Nova Scotia the black-headed fireworm completely defoliated cranberry in some bogs where it was not controlled. In others no treat- ment was required. Adults of the chain-spotted geometer were abundant in some cranberry plantings in the fall. CURCULIONIDS.—In Ontario and Quebec the plum curculio was less injurious ~ than usual on apple and stone fruits, probably because of cool weather. In Quebee the strawberry weevil, Anthonomus signatus Say, caused very little damage. In New Brunswick a general increase in numbers and damage was reported. In Nova Scotia, increased numbers caused the greatest damage in several years in both strawberry and raspberry plantings. In Prince Edward Island, damage generally was not extensive. CURRANT FRUIT FLY.—This pest commonly required control measures in areas west and north of Saskatoon, Sask. EUROPEAN APPLE SAWFLY.—In coastal areas of British Columbia this sawfly severely damaged apples on unsprayed trees. FRUIT TREE BORERS.—In the interior of British (olaminicn both the peach tree borer and the peach twig borer were minor pests. In Ontario, populations of the peach tree borer and the lesser peach tree borer were normal in the Niagara Peninsula, and reduced in numbers in Essex County, as compared with previous years, apparently because of improved control measures. In New Brunswick the roundheaded apple tree borer was less injurious than usual. 256 GRAPE PESTS.—In Ontario the leaf-feeding form of the grape phylloxera was more numerous than in 1959 in commercial vineyards. The root-infesting form, generally present, changed little in numbers, and damage was not serious. In the Niagara Peninsula the grape berry moth was less numerous than usual, and the eight-spotted forester occurred in several commercial vineyards. At Granby, Que., the grape flea beetle occurred in outbreak numbers in one vineyard. GREEN FRUITWORMS.—In Ontario Lithophane spp. were considerably more abundant and destructive than for several years in apple and pear orchards. In Nova Scotia both Lithophane spp. and Xylena were scarce and their damage was slight. IMPORTED CURRANTWORM.—In Saskatchewan this pest was reported only from Saskatoon. At Ottawa, Ont., severe infestations were observed in two gardens. In the Atlantic Provinces the insect caused much severe defoliation of currants and gooseberries. LEAFHOPPERS.—In the interior of British Columbia, leafhoppers continued to be numerous on prune and apple where not controlled. In Nova Scotia the white apple leafhopper was comparatively scarce. LEAF MINERS.—In eastern Quebec the apple leaf miner Lithocolletis mali- malifoliella Braun occurred in many orchards, but was less numerous than in 1959. In Nova Scotia, too, it was not as abundant as in 1959, but comparable numbers developed in the third generation in some orchards. LEAF ROLLERS.—In the interior of British Columbia, the fruit tree leaf roller occurred in small numbers, comparable to those of 1959, in most orchards. In Ontario and southwestern Quebec the red-banded leaf roller was a problem in only a few apple orchards. Also in Quebec, the fruit tree leaf roller was generally dis- tributed in light to medium infestations, and Psewdexentera mali Free. caused light damage to terminal growth in most apple orchards. In Nova Scotia the gray-banded leaf roller, Argyrotaenia mariana (Fern.), remained scarce and other leaf roller species caused only slight injury. MITES.—In the interior of British Columbia the European red mite, more numerous than in 1959, caused severe foliage injury in apple and pear orchards, especially in the Penticton area. In most areas of Ontario, populations of this mite on fruit trees were unusually small until mid-summer, after which they built up very rapidly. Feeding continued much later than usual, and the number of over- wintering eggs laid was the largest in many years. In the Niagara Peninsula this mite has continued to increase in numbers and destructiveness on pear for three consecutive years. In southwestern Quebec it persisted as a major pest, but in eastern Quebec it was of less importance. In New Brunswick large infestations developed in apple orchards toward the end of the season. In Nova Scotia only trace numbers occurred in most orchards, but a few required control measures. In Prince Edward Island the species was generally prevalent in commercial orchards, and damage varied with conditions. In British Columbia the pear leaf blister mite, Eviophyes pyri (Pgst.), was not very injurious to pear, but in some areas damaged apple fruit where control was inadequate. In the Georgian Bay, Ont., area infestations on apple were more common than during the previous three years. In southern Quebec the species commonly caused considerable damage in apple orchards. In Nova Scotia populations were normal and in Prince Edward Island they were smaller than usual. In the Okanagan and Similkameen valleys, B.C., the mite Tetranychus medanieli McG. was the most injurious orchard pest in 1960, mainly because of prolonged hot weather. Also in the interior of the Province, rust mites were more injurious than in 1959, infestations on cherry being much more severe than on apple. The two-spotted spider mite, the yellow spider mite, and the brown mite Bryobia arborea Morgan and Anderson continued to be minor pests. In Nova Scotia B. arborea was common on apple, but not very injurious. In both New Brunswick and Nova Scotia the cyclamen mite infested strawberry, causing considerable in- jury in the latter province. ORIENTAL FRUIT MOTH.—In Ontario damage to early and mid-season varieties of peaches was generally comparatively light, but a serious infestation developed in Elberta peaches in the Niagara Peninsula and parts of Norfolk County as a result of an unusually large brood of third-generation larvae that attacked the fruit in mid-August. In Essex County this and a partial fourth brood remained at a low population level and fruit injury was light. PEAR PSYLLA.—In the interior of British Columbia the pear psylla was numerous early in the season, but was reduced to trace numbers by insecticides and hot, dry weather. In the Annapolis Valley, N.S., it persisted as a major pest, requiring control measures in most orchards. PEAR-SLUG.—In most fruit-growing areas of Canada, the pear-slug was a minor pest. However, it severely damaged cherry in a local area in Prince Edward Island, and both pear and plum at St. John’s, Nfld. At Oliver and Osoyoos, B.C., the California pear-slug persisted in small numbers. 257 oe) PLANT BUGS.—In Nova Scotia Lygus (Neolygus) communis novascotiensis Knight, numerous in 1959, occurred in its usual small numbers. Atractotomus mali (Mey.) caused considerable injury by stinging the apples, especially Red Delicious, and Campylomma verbasci (Mey.) also caused some injury of this nature. RASPBERRY PESTS.—Raspberry cane borers, Oberea spp., were less injurious than usual to raspberry in eastern Ontario, occurred in light to moderate infesta- tions in Quebec, and in small numbers in a few plantings in Nova Scotia. A single larva of the raspberry root borer was found on raspberry at Edmonton, Alta., and in Saskatchewan the species caused moderate to severe damage in an area bounded by Saskatoon, North Battleford, and Hudson Bay. The raspberry sawfly was not reported for the third consecutive year in Saskatchewan, and was moderately common in Ontario. The spider mite T. mcdanieli infested raspberry near Fort St. John, B.C., a new distribution record in the Province. In Saskatchewan spider mites at- tacked raspberry at Francis, near Regina, and in Quebec they were injurious in several plantings. A raspberry fruitworm, Byturus sp., occurred at Bengough, Sask. Nitidulids, probably Glischrochilus quadrisignatus (Say), occurred in considerable numbers on raspberry fruit in Huron and Middlesex counties, Ont., and the rasp- berry cane maggot occurred in small numbers in Nova Scotia. SCALE INSECTS.—In the interior of British Columbia the oystershell scale continued to be numerous in abandoned apple orchards and on many species of native trees. In the Winnipeg, Man., area it damaged cotoneaster. In the Georgian Bay, Ont., area it continued to increase. In New Brunswick and Nova Scotia it was of little eco- nomic importance. In Prince Edward Island it infested fruit and shade trees fairly gen- erally. In coastal areas of British Columbia Lecanium spp. were abundant on stone fruits, pear, and holly. In the interior they were much more numerous than in 1959 on peach and apricot, especially in the Penticton and Summerland districts. In the Georgian Bay, Ont., area, a progressive tendency to increase was observed. Elsewhere in the Province they were generally scarce. At Hemmingford, Que., Lecanium coryli L. heavily infested apples in one orchard, and at Abbotsford it occurred on plum. In Nova Scotia it continued to be injurious in a few orchards. In the interior of British Columbia the European fruit scale occurred in several apple orchards, notably in the Summerland and Penticton areas. The San Jose scale was at a low ebb, and Pulvinaria sp. continued to be of little importance. In Ontario Pulvinaria sp. and the San Jose scale were scarce in most fruit orchards. TENT CATERPILLARS AND WEBWORMS.—In eastern Ontario Malacosoma americanum (F.) was irregularly distributed, but numbers appeared to be increasing. In southwestern Ontario, Malacosoma spp., almost nonexistent since 1956, appeared to be increasing in apple orchards. In New Brunswick the species caused little damage. In Nova Scotia M. americanum was common, but caused only minor injury. M. disstria Hbn. was scarce. In Prince Edward Island M. americanum was scarce. In New Brunswick the ugly-nest caterpillar was numerous in York, Queens, and Sunbury counties. In Nova Scotia the fall webworm was more abundant than in 1959, but damage to fruit was light. THRIPS.—In coastal areas of British Columbia the pear thrips caused some damage to plum and prune at Saanich. In New Brunswick and Nova Scotia, infes- tations of thrips on blueberry were generally light in commercial plantings, but large numbers were present in undeveloped areas. TORTRICIDS.—In coastal British Columbia the orange tortrix was very numerous on loganberry, raspberry, and chrysanthemum in home gardens. In the Saanich district the omnivorous leaf tier was locally numerous on young apple trees, but caused little damage to strawberries. In Prince Edward Island Cnephasia virgaureana Treit was widely distributed. Infestations generally were light, but moderate damage occurred in many new plantings of strawberries. In Newfoundland, too, some damage occurred in strawberries. YELLOW-NECKED CATERPILLAR.—Where this insect appeared, it was only a minor pest. ZEBRA CATERPILLAR.—For the first time in many years, this caterpillar caused appreciable damage in eastern Quebec, light infestations occurring on turnip and strawberry. INSECTS AFFECTING GREENHOUSE AND ORNAMENTAL PLANTS ALFALFA LOOPER.—In coastal British Columbia the alfalfa looper damaged — chrysanthemum in several commercial greenhouses. APHIDS.—In southwestern British Columbia the green peach aphid commonly damaged the blooms of greenhouse chrysanthemums. The rose aphid damaged holly in many plantings. Myzocallis walshii (Monell) was a nuisance on red oak in Van- cauver streets, and unidentified aphids damaged tulip bulbs in storage. In the interior of the Province, from the Okanagan north to the Peace River area, Adelges cooleyi (Gill.) commonly infested spruce. In northern Alberta, too, Adelges sp., 258 \ commonly attacked spruce. At Saskatoon and Big River, Sask., delphinum and sweet peas were commonly infested by aphids. In Winnipeg, Man., elm was heavily infested. In the Chatham, Ont., area, a large aphid, Tuberolachnus salignus (Gm.), was common on willow. In Quebec generally, aphids were numerous on flowers and hedges, and Hriosoma ulmi (L.) was more of a nuisance than usual on elm in and about Quebec City. At Ste-Anne-de-la-Pocatiére Hriosoma sp. was numerous on maple. At Fredericton and Oromocto, N.B., aphids were abundant on dahlias. At St. John’s, Nfld., the balsam twig aphid severely attacked balsam, and in eastern areas of the Province EF. ulmi was abundant on elm. CHINCH BUGS.—The hairy chinch bug caused some severe damage to lawns at New Minas, N.S. CURCULIONIDS.—The weevil Brachyrhinus singularis (L.), first recorded in British Columbia at Victoria in 1937, has since spread extensively in the Province and in 1960 was found for the first time on the Experimental Farm at Saanichton, where it damaged rhododendron. At Saskatoon, Sask., the rose curculio moderately damaged roses. The white-pine weevil was reported from Manitoba, and occurred commonly on white, dwarf, and Scots pine in Hastings County, Ont. CYNIPID WASPS.—These gall-forming wasps moderately infested roses in northern Alberta and at Kindersley and Southey, Sask. EIGHT-SPOTTED FORESTER.—tThis pest of Virginia creeper was abundant in southwestern Quebec. ELM LEAF BEETLE.—The elm leaf beetle occurred very commonly in eastern Ontario. EUROPEAN PINE SHOOT MOTH.—Young pine throughout Prince Edward Island were attacked by this pest. GREENHOUSE WHITEFLY.—In southwestern Ontario this insect was much more abundant than usual on greenhouse vegetables, especially cucumber, during the spring. LACE BUGS.—Corythucha sp. occurred very commonly on elm in eastern Ontario. A POPLAR LEAF BEETLE.—In western Manitoba Chrysomela crotchi Brown caused extensive defoliation of poplar. ~LEAFHOPPERS.—tThe Virginia-creeper leafhopper was abundant at Saskatoon, Sask., and Ribautiana ulmi (L.) damaged elms extensively in eastern Newfoundland. LEAF MINERS.—In eastern Ontario the arborvitae leaf miner was common on white cedar, and the basswood leaf miner was much less numerous than in 1959 on basswood. The birch leaf miner. commonly infested ornamental and native birch in Eastern Canada. The lilac leaf miner heavily infested lilac in coastal British Columbia and occurred generally throughout Eastern Canada. In Quebec a leaf miner, Lithocolletis fragilella F.&B., occurred commonly on honeysuckle. MAPLE LEAF CUTTER.—Infestation of maple by this insect in eastern On- tario was lighter than in 1959 and far below that of the period 1940-1950. MITES.—The eriophyid mite Acaricalus hederae (K.), recorded for the first time in Canada during February, 1959, has become one of the most serious economic pests of holly in the coastal areas of British Columbia. It is present in over 95 per cent of the holly plantings in this area and is not controlled by the present spray program for other pests. The clover mite damaged bedding plants at Kamsack and Saskatoon, Sask. Eriophyid mites damaged many hosts in Manitoba. The two-spotted spider mite was less injurious than in several previous years to ornamentals in eastern Quebec. The maple bladder-gall mite continued to disfigure maple in south- western Quebec, and a bladder- gall mite Phyllocoptes magnificus Hodgk., was numerous on Norway maple in St. John’s, Nfld. POPLAR BORER.—This pest of poplar was common in eastern Ontario. SAWFLIES.—The larch sawfly, though prevalent on larch in Hastings County, Ont., was less numerous than in 1959. In Quebec it was reported to be numerous. The red-headed pine sawfly was very scarce in eastern Ontario. The mountain-ash sawfly severely defoliated mountain ash in both Prince Edward Island and New- foundland. SATIN MOTH.—Infestation of poplar by the satin moth in the St. John’s, Nfld., area was generally very light. SCALE INSECTS.—Holly seale occurred generally on holly in the Chilliwack, B.C., area. The pine needle scale continued to be abundant on ornamental and shelter- belt evergreens in Manitoba. The juniper scale was generally distributd in Ontario. _ SPRUCE BUDWORM.—This budworm attacked ornamental spruce at Okotoks, Gee ee fairly injurious in Ontario, and present in small numbers in Prince Edward slan TENT CATERPILLARS AND WEBWORMS.—Malacosoma spp. were numerous in the lower Fraser Valley, B.C., and M. disstria Hbn. occurred in infestation numbers 259 at Langley, Mission, Vernon, and Hazelton. In Saskatchewan Malacosoma spp. were less abundant than in 1959, but in Ontario and Quebec, although larvae were fairly scarce, adults were numerous, indicating a rising trend in numbers. In the Vernon and Kelowna, B.C., districts the fall webworm was quite numerous. In northern Alberta it was only rarely reported and in eastern Ontario infestation was quite spotty, especially in northern regions. In coastal British Columbia the juniper web- worm caused considerable damage. In Quebec and New Brunswick the ugly pe caterpillar was numerous, but less so than in 1959 in the former province. THRIPS.—In British Columbia, thrips damage occurred commonly on green- house chrysanthemums and outdoor roses. In Eastern Canada, damage by the gladiolus thrips was commonly reported. A VARIEGATED FRITILLARY.—Euptoetia claudia (Cram.), an occasional pest of violet and pansy, caused some damage in northern Alberta and at Saskatoon, Old Wives, and Melfort, Sask. WALNUT CATERPILLAR.—As usual in southwestern Ontario, Bace walnut was commonly defoliated by this pest. WHITE-MARKED TUSSOCK MOTH.—Ornamentals were frequently damaged by larvae of this tussock moth in the Quebec City area. INSECTS ATTACKING MAMMALS AND BIRDS BAT BUG.—One infestation of the bat bug was recorded at Ottawa, Ont., and one at Vernon, B.C. BED BUG.—Reports of the bed bug were few in British Columbia and Alberta, fairly numerous in Saskatchewan, few in Manitoba, Ontario, and Quebec, and fairly numerous in Prince Edward Island. ¢ BLACK FLIES.—In British Columbia and Alberta, black fly populations re- mained about normal. However, in the Medicine Hat, Alta., area, they had freely attacked humans for two successive years. In Saskatchewan they were less abun- dant than in 1959. The usual spring outbreaks of Simulium arcticum Mall. did not occur, although the species caused some annoyance along the South Saskatchewan River in late summer. Also present were S. meridionale Riley, and S. griseuwm Coq. the most abundant species. In Manitoba black flies were abundant and annoying, especially in resort areas, their attacks continuing until October. In eastern Ontario and the Ottawa River Valley they occurred in large numbers in early summer, and in an unusual outbreak in mid-September. In Newfoundland they were a nuisance throughout the season. BLACK WIDOW SPIDER.—This pest continued to be numerous in much of the interior of British Columbia, though inquiries at Kamloops were fewer than in the previous two years. BLOW FLIES AND FLESH FLIES.—In northern Alberta, larvae of Pro- tophormia terraenovae (R.-D.) were removed from a wound on a musk ox ealf, and over 200 larvae of Sarcophaga sp. were removed from a Richardson’s ground squirrel. In Ontario a larva of Cuterebra sp. probably horripilum Clark, was removed from the neck of a rabbit. In the Avalon Peninsula, Nfld., the sheep blow fly Phaenicia sericata (Mg.) severely attacked sheep in many localities. BOT FLIES.—An increase in parsitism of sheep by the sheep bot fly in British Columbia caused some concern. In Alberta this species occurred at Barrhead, and larvae of a deer nose bot, Cephenemyia jellisoni (Tns.), were removed from the nose and throat of a deer at Sheep River. CATTLE WARBLES.—Population studies of Hypoderma bowis (L.) and AH. lineatum (DeVill.) in British Columbia indicated that the population decreased five to ten per cent during the spring as a result of weather conditions adverse to pupation and oviposition. CULICOIDES.—In British Columbia Culicoides spp. continued to be a nuisance, and at Saskatoon, Sask., C. denningi F.&P. was annoying from June to September. Wi ASC renecemialides spp. were reported from British Columbia, and com- monly attacked family pets and humans during the late summer and fall in Ontario and Quebec. In Saskatchewan, the human flea, rarely recorded in Canada, ws identified in one infestation, and a chicken flea, probably Ceratophyllus niger Fox, attacked poultry and humans, in a poultry house. At Duntroon, Ont., the European chicken flea severely attacked humans. A HELOMYZID.—At Fredericton, N.B., Tephrochlamys rufiventris (Mg.) de- veloped in large numbers in poultry manure. HORN FLY.—In Alberta horn fly numbers were about normal in the Leth- bridge area, but in the Edmonton area they had increased in four consecutive years from approximately 50 flies per animal to some 200 flies per animal. The northward spread had reached Grand Prairie to the west and Lesser Slave Lake to the north. In Ontario and Quebec the insect continued to be numerous on eattle. 260 HORSE FLIES AND DEER FLIES.—A biting-fly survey in northern Alberta revealed an unusually large population of tabanids in all parkland and wooded areas examined. In Saskatchewan Chrysops aestuans Wulp was recorded at Regina. In Manitoba, horse flies and deer flies were less numerous than usual, probably because of hot, dry weather which reduced breeding sites. In Eastern Canada Chrysops spp. were very numerous in Ontario and a survey revealed tabanids to be very numerous from Quebec eastward to the Atlantic. LICE.—In British Columbia, unusually heavy infestations of cattle lice occurred late in 1959 and into 1960, especially in the Cariboo and Chilcotin areas, but they were soon reduced to normal numbers. In Alberta and Manitoba infestation con- tinued to be sporadic. MITES.—Chicken mites occurred commonly on poultry, and Dermanyssus gallinae (DeG.) occasionally migrated into buildings from birds’ nests, frequently attacking humans. MOSQUITOES.—In British Columbia, mosquitoes were not unusually numerous, but favourable weather conditions prolonged the emergence season. In southern Al- berta increased use of water for irrigation resulted in increased numbers of the pest. In Saskatchewan favourable breeeding conditions produced unusually large numbers in northern areas. In southen areas mosquitoes were briefly numerous in mid-May and August. In eastern Ontario ideal breeding conditions produced unusually large populations early in the season. In Prince Edward Island, mosquitoes were less numerous than usual, because of dry weather, but in Newfoundland they were a nuisance throughout the season. A MUSCID.—In Ontario Musca autumnalis DeG. was rated one of the major pests of livestock, especially cattle. A survey in Quebec and eastward to the coast indicated that the species was widely distributed, but it was not generally considered a serious pest. SNIPE FLIES.—Several reports were received of snipe fly (Symphoromyia) activity in southwestern and northwestern areas of Alberta. TICKS.—In the interior of British Columbia, populations of Dermacentor ander- soni Stiles were about normal although adult activity commenced at a record early date (Feb. 3) and extended over a record period of 20 weeks. Three cases of paralysis in humans were reported, but none proved fatal. No survey of the ear tick, Otobius megnini (Dugés), was made, but infestations were known to occur in three herds of cattle in the Armstrong-Enderby-Salmon Arm area. Infestation of moose and deer by the winter tick, Dermacentor albipictus (Pack.), was comparatively light. In Alberta this species occurred on caribou on the Alberta Game Farm, and D andersoni was removed from a child at Calgary. In Saskatchewan ticks were more numerous than usual. D. andersoni was recorded five times on humans and once on a calf. Dermacentor variabilis (Say) was recorded three times in southeastern Saskatchewan, and caused much annoyance in resort areas and on livestock in Manitoba. D. andersoni was recorded from Rosetown and Dodsland, Sask. In On- tario few inquiries concerning ticks were received. WASPS, HORNETS, AND BEES.—These annual pests continued to cause an- noyance about dwellings, garages, schools, and picnic grounds. BUILDING PESTS ANTS.—In the Wellington, B.C., district, ant species found in bee colonies included Lasius sitkaensis Perg., Tapinoma sessile (Say) and Myrmica brevinodis Emery. In the Prairie Provinces, ants were apparently considerably less important as household pests than elsewhere in Canada. In Eastern Canada, ants continue to be major pests in buildings and lawns. A severe infestation of Myrmica brevinodis Emery occurred in a house at Vineland, Ont. Indoor infestations of Solenopsis molesta Say were recorded at Oshawa and Midland, Ont., and Granby, Que. Formica fusca L. occurred at Scarborough, Ont. Monomorium pharaonis (L.) was an increasingly common pest in buildings in most eastern provinces, and Camponotus spp. were very numerous in the St. John’s, Nfld., area. BORBORIDS.—Infestations of borborids, especially Leptocera fontinalis (Fall.), occurred in Saskatchewan in schools at Kelliher, Davidson, Batoche, and Wartime; and in homes at Plato and Domremy. At Fredericton, N.B., Leptocera n. sp., near carinata Spuler, heavily infested a poultry house, having developed in the manure. BOXELDER BUG.—This insect was a common pest in and about dwellings in the Kamloops and Okanagan Valley areas of British Columbia. In the Prairie Provinces it was an occasional pest, and in Eastern Canada it continued to be comparatively scarce. CARPET BEETLES.—In coastal areas of British Columbia, Anthrenus verbasci (L.) was the principal pest species. In the lower Fraser Valley, A. verbasci and A. scrophulariae (L.) were both numerous. In the interior A. scrophulariae and 261 Attagenus piceus (Oliv.) were most commonly reported. In the Prairie Provinces A. piceus was one of the principal household pests, but damage to fabrics was not excessive. In Ontario and Quebec, carpet beetles were very commonly reported, in- festations of A. piceus outnumbering A. scrophulariae about four to one. Attagenus pellio L. was recorded from Deep Rock, N.S. The only previous records of this species in Canada were from Nova Scotia in 1871 and 1902. A. piceus and A. scro- phulariae were fairly commonly reported in the Maritime area. CLOTHES MOTHS.—Inquiries concerning clothes moths were not numerous, but control measures are so well known that most infestations are not reported. CLUSTER FLY.—tThis annual pest continued to be numerous in Eastern Canada. COCKROACHES.—In British Columbia the oriental cockroach was recorded from Nelson and the German cockroach was a pest in some institutions. At Edmonton, Alta., the Australian cockroach was found in bananas on four occasions. In Eastern Canada the German cockroach occurred in scattered infestations as usual, and occasional records were received of the oriental, American, and Australian cock- roaches. The brown-banded cockroach, now well established in Ontario, occurred in many urban centres. The woodland cockroach Parcoblatta pennsylvanica (DeG.) infested many cottages and motels in Ontario and Quebec. CRICKETS.—Ceuthophilus spp. occurred fairly commonly in buildings in AlI- berta, Saskatchewan, Ontario, and Quebec. The house cricket was recorded in Ottawa and Oakville, Ont. A severe outbreak of the field cricket in the Winnipeg, Man., area caused much damage in gardens and much inconvenience to householders. The crickets were heavily parasitized by mermithids, which left the hosts in sufficient numbers to add materially to the disturbance. EUROPEAN EARWIG.—In Ontario this pest was recorded for the first time in eastern Ontario and the Niagara Peninsula, being recorded from Carleton Place, Niagara Falls, and Port Colborne. Thornbury, also a new record, was not as far removed from the initial area of infestation. FLIES.—A survey in the Skeena Valley, B.C., revealed an abundance of the little house fly, Fannia canicularis (L.), but apparent absence of the house fly, Musca domestica L. The latter species was more abundant than usual at Saskatoon, Sask., and in eastern Quebec. LARDER BEETLE.—Infestations in dwellings were widespread in Eastern Canada, where the larvae commonly developed on dead cluster flies in attics and wall spaces. In eastern Quebec the species was the most common household pest. MASKED HUNTER.—tThis predator, seldom reported, was found in association with a severe infestation of spider beetles in bone meal and fish meal at Vancouver. MITES.—In the lower Fraser Valley and the interior of British Columbia, and in Alberta, Saskatchewan, Ontario, and Quebec, the clover mite was an important pest of dwellings during spring and early summer. In Manitoba, reports were fewer than usual and in the Atlantic Provinces a dearth of reports suggested light in- festation. SILVERFISH.—Lepismatidae continued to be commonly reported and frequently built up to major infestations in apartment blocks, especially in new buildings. STINK BEETLE.—In British Columbia this beetle was a fairly common pest in buildings at Terrace in the Skeena Valley, and invaded a dwelling at Cranbrook. STRAWBERRY ROOT WEEVIL.—In Alberta and Saskatchewan this weevil was numerous. In Manitoba it invaded dwellings at Hamiota and Boissevain. In Eastern Canada it occurred in normal numbers in most areas, but was somewhat scarce in New Brunswick. TERMITES.—In British Columbia Zootermopsis sp. occurred at Duncan, and unspecified species of termites at Mission, Victoria, and Wellington. Two infesta- tions of Reticulitermes hesperus Banks occurred at Kamloops. WOOD BORERS.—Near Kamloops, B.C., logs in a cabin were damaged by the beetle Phymatodes dimidiatus (Kby.). In Ontario, powder-post beetles were com- monly reported damaging buildings, occasionally furniture, and in one case a bamboo purse. Other borers occasionally damaged log cabins. An ash borer, Leperisinus aculeatus (Say), probably emerging from firewood, infested buildings at Ottawa and Richmond. The wharf borer was reported once at Ottawa. In Prince Edward Island, powder-post beetles continued to cause damage in some areas. STORED PRODUCT INSECTS STORED GRAIN INSECTS.—In British Columbia the brown house moth and the white-shouldered house moth were the two insects most frequently encountered in terminal elevators. Other insects found in smaller numbers were: the granary weevil, the yellow mealworm, Ptinus ocellus Brown, and Pseudeurostus hilleri (Reit.). Psocids and mites were also present. Black carpet beetles were taken in elevators at Creston and Wynndel. In the Prairie Provinces stored grain insects continued to 262 RAR, ADE po Pee ee OP constitute the major stored product problem. Unusually mild fall weather extended insect activity and contributed to outbreaks that normally do not occur. The principal pests included the rusty grain beetle, the red flour beetle, the confused flour beetle, the saw-toothed grain beetle, the foreign grain beetle, the meal moth, the yellow mealworm, the hairy spider beetle, a fungus beetle Lathridius (prev. Enicmus) minutus (L.), and Anthicus floralis (L.). Mite species included Acarus siro L. and Glycy- phagus destructor (Schr.), a cannibal mite Cheyletus eruditis Schr., and a rodent mite Haemolaelaps casalis (Berlese). _ MILL AND WAREHOUSE PESTS.—In British Columbia the Mediterranean flour moth occurred in outbreak numbers in many feed mills; the spider beetle Ptinus ocellus Brown occurred commonly in coastal areas; and the black carpet beetle was generally the most frequently recorded pest. The various pests of mill and warehouse in the order of frequncy of recorded occurrence were as follows: the black carpet beetle, the cadelle, the Mediterranean flour moth, the yellow meal- worm, P. ocellus, the brown house moth, the white-shouldered house moth, the meal moth, the larder beetle, the varied carpet beetle, the confused flour beetle, the Indian- meal moth, the saw-toothed grain beetle, the granary weevil, the drug-store beetle, and Dermestes signatus Lec. In the Prairie Provinces Ptinus villiger (Reit.) oc- curred commonly in flour warehouses. The confused flour beetle was the most common pest in flour mills in Saskatchewan. Other mill pests included the yellow mealworm, the webbing clothes moth, the black carpet beetle, Trogoderma parabile Beal, Tri- bolium madens (Charp.), and Ptinus raptor Sturm. P. raptor also infested a mill at Halifax, N.S., and P. ocellus occurred commonly in warehouses and dwellings in Newfoundland. FOOD-INFESTING INSECTS.—Oryzaephilus spp. and Tribolium spp., es- pecially T. confuswm Duv., appear to have been generally the most common pantry pests in Canada in 1960. Other species that were commonly reported included the larder beetle, the black carpet beetle, the yellow mealworm, the meal moth, spider Besa the Indian-meal moth, the drug-store beetle, silverfish, and the cigarette eetle. (Accepted for publication: April 4, 1961) 263 IV. NOTES = COLOUR AFFECTS THE LANDING OF BLOODSUCKING BLACK FLIES (DIPTERA: SIMULIIDAE) ON THEIR HOSTS D. M. Davirs' Simulium venustum Say, is a common bloodsucking fly of northeastern North America. In a preliminary study, females of this species were shown to land more frequently on certain coloured cloths than on others, dark blue being the most frequented (1). More recently in Algonquin Park, Ontario, a more thorough study of the effect of colour on the frequency of landing of simuliids was made, while the writer was working for the Ontario Research Foundation, Toronto, Ontario. The colours used, were carefully chosen to fit certain values of wavelength, intensity and purity according to the Munsell Color System. ATTRACTANCY OF MUNSELL COLOURS (hue) (lightness value) / (chroma or purity) 30 25 20 [5 10 RELATIVE ATTRACTANCY POPS. 6 BG G GY Y YR R. RP oP MUNSELL HUES (COLOUR) Fig. 1. The relative “attractancy” of coloured cloths to female black flies (mainly S. venustum) based on the number landing on each cloth in unit time. The total number landing was 5,700. The lightness value of the cloths was 3 and the chroma 8. Note: P=purple, B=blue, G=green, Y=—yellow and R=red. iMcMaster University, Hamilton, Ontario. Proc. ent. Soc. Ont. 91 (1960) 1961 267 The observer, acting as the host, sat in the shade with a large black cloth wrapped around his outstretched legs. On this black flat surface, two 6-inch square cloths of different colours were placed side by side and the number of black flies, mainly S. venustwm females, landing on each was counted simultaneously during a two-minute interval. In each experiment three cloths were used so that each pair was tested three times, i.e, AB, AC, BC, CA, CB, BA, BC, CA, AB.In this way bias due to changing environmental conditions was reduced. Squares of coloured papers were obtained from: the Munsell Color Company in Baltimore, U.S.A. and cloths were-dyed by the Ontario Research Foundation to match Munsell standard colours(2). These colours can be divided into three components: hue (wavelength), intensity (lightness) and chroma (purity). The first component to be studied was intensity. To keep the hue and chroma constant, four neutral colours were used: black, dark grey, light grey and white. Flies landed most frequently on dark grey and then on black, light grey and white in order of decreasing frequency. Using three blue cloths of the same hue and chroma in another experiment, the frequency of landing was found to decrease with an increase in the intensity of the light reflected from the cloth. This was also shown by experiments with two chartreuse cloths and two purple-blue cloths. The hue was also studied to find its effect on the frequency of landing, while intensity and chroma were constant. Red-purple (maroon) was found to be the most frequented (Fig. 1) with purple and purple-blue next, and red and blue about equally selected by the flies. Blue-green, chartreuse and yellow-red (orange) were less attractive than white. This general trend was manifest at the three levels of intensity tried. Tests for the importance of chroma were less extensive but black flies landed less frequently on cloths of high chroma than on duller colours of the same wave- length and intensity. The reflectances of all these materials have been measured throughout the visible and the longer ultraviolet wavelengths. A fuller analysis and a discussion of the response of black flies to reflected light will be presented elsewhere. Grateful acknowledgement is made to Dr. A. M. Fallis for his encouragement and guidance, and to him and Dr. G. F. Bennett for acting as observers in certain experiments. Summer facilities were provided by the Department of Lands and Forests of Ontario. LITERATURE CITED 1. Davies, D. M. (1951) Some observations of the number of black flies (Diptera, Simuliidae) landing on coloured cloths. Canad. J. Zool. 29: 65-70. 2. NICKERSON, D. (1948) Color and its description. Bull. Amer. ceram. Soc. 27: 47-55. (Accepted for publication: March 1, 1961) O AN INFESTATION OF COMSTOCK MEALYBUG, PSEUDOCOCCUS COMSTOCKI (KUW.) (HOMOPTERA: COCCOIDEA) ON PEACH IN ONTARIO.’ J. H. H. PHILLIPS The Comstock mealybug, Pseudococcus comstocki (Kuw.), was first reported in Ontario in 1945 by Shepherd (3) as seriously infesting Catalpa spp. in the Niagara Falls area. Boyce (1) introduced three parasite species, Allotropa convexifrons Mues., A. burreli Mues., and Pseudaphycus malinus Gahan from Virginia in 1946 and 1947 to combat this infestation. Since 1945 the mealybug has been observed as isolated infestations on catalpa in the eastern part of the Niagara Peninsula, and in 1953 it was found attacking Japanese plum near Queenston, Ontario. It has been reported as a serious pest of apple (4) (5) in Virginia, and in New Jersey as a pest of both apple and peach (2). In October, 1959, serious outbreaks of this mealybug were discovered in two adjacent orchards in the vicinity of Niagara-on-the-Lake. One was in a small Elberta peach orchard with an adjoining block of mixed fruit; the other was in a large peach orchard, only part of which was affected. The owners stated that they had iPublication No. 6, Research Laboratory, Research Branch, Canada Department of Agriculture, Vineland Station, Ontario. Proc. ent. Soc. Ont. 91 (1960) 1961 268 never used DDT or any phosphate insecticides in their peach orchards and had used only lead arsenate to control the plum curculio. Both stated that they had difficulty in selling their Elberta peaches in 1959 because of the large amount of sooty fungi growing on the fruit. Though the peach trees had a considerable number of cottony egg masses on the rough bark, in pruning scars, and in cankers, they did not appear to be seriously injured by the mealybug. Japanese plum in the same orchard was much more heavily infested and a few trees were seriously injured with most of the tops of the trees dead (Fig. 1 & 2). Quince, pear, sweet and sour cherry, and European plum in the same orchard were not infested. Fig. 1. Egg masses of Pseudococcus comstocki (Kuw.) on the trunk and branches of a Japanese plum tree. The source of infestation appeared to be seven large catalpa trees that were growing along the road between the two orchards. Two of these were dead and all showed signs of having been heavily infested, though no live eggs were found on them. Egg masses collected from the peach trees contained a large number of viable eggs of the mealybug and many cocoons of a parasite. The parasite was identified by C. D. F. Miller ofthe Entomology Research Institute, Research Branch, Canada Department of Agriculture, as Pseudaphycus malinus Gahan. Since the orchards are about nine miles from the site where parasites were liberated by Boyce in 1946 and 1947, it appears that at least one of the parasite species is well established in the area. Eggs of the mealybug began to hatch in mid-May soon after the petals had ee from Elberta peach and many crawlers were found on the infested trees at that time. 269 A spray of parathion, 15 per cent w.p., 14% Ib. per 100 gal. of water, aoe by the growers just after the eggs started to hatch and again about 12 days later, controlled the infestation. These sprays corresponded with the recommended sprays for control of the plum curculio. Fig. 2. Japanese plum tree showing dead branches as the result of attack by Pseudococcus comstocki (Kuw.). ey LITERATURE CITED (1) Boyce, H. R. (1948). Parasites of the Comstock mealybug in Ontario. Rep. ent. Soc. Ont. 78: 1947: 68-70. (2) Driccrrs, B. F. and HANSENS, E. J. (1948). The Comstock mealybug on apples and peaches in New Jersey. J. econ. Ent. 36: 222-226. (3) SHEPPARD, R. W. (1945). Notes on the occurrence of the Comstock mealybug, Pseudococcus comstocki (Kuw.), at Niagara Falls, Ontario. Canad. Ent. 77: 217. (4) SCHOENE, W. J. (1941). Plant food and mealybug injury. J. econ. Ent. 34: 271-274. (5) Ene ee M. (19386). Comstock’s mealybug as an apple pest. J. econ. Ent. (Accepted for publication: March 1, 1961) 0 RESULTS OF REARING SOME COCCINELLID (COLEOPTERA: COCCINELLIDAE) LARVAE ON VARIOUS POLLENS B. C. SMITH? Previous studies (1) showed that the predaceous ¢occinellid beetle Coleomegilla maculata lengi Timb. can be reared in the laboratory on the pollen of gray birch, corn, hemp, and hornbeam. At least one of these, corn pollen, is part of the natural diet of this predator and may be important for survival, particularly when prey ig~ntomology Research Institute for Biological Control, Research Branch, Canada Department of Agriculture, Belleville, Ontario. Proc. ent. Soc. Ont. 91 (1960) 1961 270 ) are scarce. The results of further feeding tials with C. maculata and new trials with Cycloneda sanguinea (L.), and Coccinella trifasciata L. are given here. At least 10 first-instar larvae of each species were confined individually in cells with each pollen tested. The plant species and dates of collection were: gray birch, Betula populifolia Marsh., May 5; common cat-tail, Typha latifolia L., June 20; corn, Zea mays L., August 9; hemp, Cannabis sativa L., July 11; hemlock, Tsuga canadensis (L.) Carr., May 25; shagbark-hickory, Carya ovata (Mill.) K. Koch., June 1; horn- beam, Carpinus caroliniana Walt, May 6; red oak, Quercus rubra L., May 17; and butternut, Juglans cinerea L., May 17. The pollens were dried at about 20°C., cleaned by sieving, and stored in darkness at 4°C. until used. C. maculata developed from the first-instar larva to the adult stage on the pollens of cat-tail and butternut. The develepment times were: 28.0+1.2 and 30.7+0.9 days respectively. Survival to the adult stage was 30 per cent on cat-tail pollen and 40 per cent on butternut pollen. There was no development beyond the pupal stage, on hickory pollen, and on the pollens of hemlock and oak the larvae developed only to the third instar. C. sanguinea completed three instars when fed on hemp pollen, two on corn, and one on the pollens of birch, hemlock, hickory, hornbeam, and oak. C. trifasciata completed the first instar when fed on the pollens of corn and butternut but failed to develop on the other pollens listed. The results indicate that larvae of C. maculata are the most generalized feeders of the species tested. C. maculata can be reared from the first-instar larva to the adult stage on the pollens of butternut, cat-tail, birch, corn, hemp, and hornbeam. Several pollens, particularly those produced after May 15, may be part of the natural diet of certain coccinellid larvae. LITERATURE CITED (1) SmitTH, B. C. (1960). A technique for rearing coccinellid beetles on dry foods, and influence of various pollens on the development of Coleomegilla maculata lengi Timb. (Coleoptera: Coccinellidae). Canad. J. Zool. 38: 1047-1049. (Accepted for publication: March 1, 1961) O COMMON NAMES OF INSECTS’ C. G. MacNay’ This note, written on request, explains why some insects need common names, the importance of officially approved lists of such names, the principles involved in the choice of a common name, and the procedural steps pertinent to its submission for approval and subsequent handling by the various common names committees. Both man and many insect species persist in wanting the same things at the same time. This has resulted in a struggle that began long before the dawn of civilization and doubtless will continue as long as the human race endures. To earry on a struggle with any degree of success, one should study and know his enemy. To do this one must work at it and for this purpose, if no other, it is essential that the enemy have a convenient name. It does not follow, however, that all insects are enemies. Many are useful to man and it is correspondingly important that these, too, have convenient names. On the other hand, the great majority of insects are of such minor economic importance as to require nothing more than a scientific name. The basic name of each insect is its scientific name, recognized on a world basis. Common names are intended mainly for use in dealing with the public, either directly, or indirectly in the form of extension literature, farm periodicals, news- casts, and the like. Scientific names are inadequate and in many ways unsuitable for this purpose. Common names are the outgrowth of usage in all phases of entomological activity from farm to university. They are not international, many having quite local usage, and as a result some insects have acquired several common names. This, of course, causes confusion and points up the importance of an official list. The most important recommendation for a common name is that it is being used freely and sensibly and that it is thoroughly popular. iContribution No. 4, Scientific Information Section, Research Branch, Department of Agriculture, Ottawa, Canada, prepared at the request of the Board of Directors, Entomological Society of Canada. 2Chairman, Committee on Common Names, Entomological Society of Ontario. Proc. ent. Soc. Ont. 91 (1960) 1961 201 In 1903 the American Association of Economic Entomologists selected a Com- mittee on Nomenclature for the purpose of securing the adoption of uniform names for the more common insects in the U.S.A. In 1908 the first list, consisting of 142 names, was published. Since that time five revisions have been published, the latest appearing in the Bulletin of the Entomological Society of America Vol. 6 (4), December, 1960. In 1952 a list of French common names was published by the Quebec Society for the Protection of Plants. This list developed from one published by Abbé Provancher in 1871. Also in 1952, the Entomological Society of Canada set up a Committee on Common Names of Insects. This committee now is composed of the chairmen of the seven regional common names committees in Canada, and two additional members, one of whom must be a taxonomist. It recognizes the names published in both official lists and supports them by periodically proposing additional names for incorporation in the lists. Currently, the Common Names Committee of the Entomological Society of Ontario consists of four members, namely, W. W. Judd, L. A. Miller, W. Y. Watson, and C. G. MacNay (chairman). It is the duty of each committee member to encourage the members of regional societies to propose names when and where they are needed. Specific forms for this purpose are available from your regional committee mmbers. Each proposal is first considered by the local committee and, if approved, is forwarded to the chairman of the national committee, who will have the members of his committee vote on it. If it survives this vote it is forwarded to the Committee on Common Names of Insects of the Entomological Society of America for final consideration. If approved it is published in the Bulletin of the Entomological Society of America. If no objections are recorded within thirty days following publication, the name becomes official. In recent years an appreciable number of common name proposals, sent forward by the Entomological Society of America, have been added to the official names list. If the proposed name is rejected by any of the three committees, it is returned to the proposer through the chairman of the regional committee with reasons for its rejection and, in some cases, suggestions for changes that would permit resub- mission, if it is considered that the insect really needs a common name. Before proposing a common name, it is strongly suggested that you read an article entitled “An Appeal for a Clearer Understanding of Principles Concerning the Use of Common Names”. This appeared in the Journal of Economic Entomology 46: 207-211, 19538. In it the following principles are supplied as guides in the process of choosing additions to the Common Names List. 1. Included species will in most cases inhabit the United States, Canada, or their possessions and territories. In special cases, other species may be added. 2. The list is intended for those insects and related invertebrates which com- monly are of concern to applied entomologists because of their economic im- portance, striking appearance, abundant occurrence, or for any other suffi- cient reason. 3. Where possible, more than three words should be avoided in a common name, but four are permissible if reasons are sufficient. 4. In the case of names having two parts, one of them a group name, it is desirable that a single word be used for the group name if it is used in a sense that is systematically correct. Example: ‘house fly’, as contrasted with “citrus whitefly”. 5. The use of parts of the scientific name in the common name is undesirable unless the words involved are thoroughly established by usage as a common name. 6. Only in special cases should an insect have more than one common name. 7. In the case of insects of concern to entomologists in both the larval and adult stages, the name preferably should apply to the most important or best known stage, or to the one for which usage has established the better name. 8. In all cases involving the adoption of new common names or changes in those previously established, the fullest consideration should be given to past usage and the probable future usage. Members who wish to recommend new names or changes in existing one should accept the responsibility of making the necessary investigation. In so far as possible, the considered opinions of ento- mologists experienced with the insects concerned should be obtained before names are proposed, and all of the available evidence, both for and against, should accompany the proposal when it is submitted to the Committee. O 272 V. THE SOCIETY ¥ ie, Se = wate e PROCEEDINGS OF THE NINETY-SEVENTH ANNUAL MEETING ENTOMOLOGICAL SOCIETY OF ONTARIO November 23-24, 1960 The 97th Annual Meeting of the Entomological Society of Ontario was held in War Memorial Hall, Ontario Agricultural College, Guelph, Ontario on the 23rd and 24th of November, 1960. The meeting was opened by the President, Mr. D. G. Peterson, at 10:15 a.m., Wednesday, 23rd November, 1960. © The president introduced Dr. J. D. MacLachlan, President of the College who welcomed the Society. Dr. MacLachlan’s address of welcome was followed by some short announcements by Mr. Peterson who then introduced the guest speaker, Dr. T. W. M. Cameron, Director, Institute of Parasitology, Macdonald College, Quebec. The meeting then proceeded as per programme. The annual business meeting was held at 11:45 am. Thursday, November 4th, 1960 in the Lounge, War Memorial Hall, O. A. College. On a motion by Messrs. Dustan and Heming the minutes of the last meeting were accepted as published in Vol. 90 — “Proceedings of the Entomological Society of Ontario.” Business Arising: The President informed the members that a revision of the constitution had been approved by the Minister of Agriculture and suggested that we work with this new edition for some time before suggesting any changes. He pointed out that the constitution now permitted us to honour individuals by appointing them as fellows. He asked that names be forwarded to the Secretary. Report on Directors’ Meeting: The President reported on the matters discussed at the Directors’ Meeting which was held on the 23rd November, 1960. a. Agreement with Entomological Society of Canada. There now exists a new agreement between the two societies which includes procedure for the levying of fees and setting of library exchanges. b. ae poy had contributed $100.00 towards the cost of publishing the Zoological ecord. ce. The transfer of the library from Massey Hall to the New Biology building was under consideration. : d. The Society owned some very ancient insect cases which were at present in the Department of Entomology and Zoology, O.A. College. As new cases were provided in the new building, the Board of Directors had instructed the Secretary- Treasurer to dispose of these cabinets in the best interests of the Society. Reports: The highlights of reports prepared by the Common Names, Library, and Pub- lications Committee chairman were given by the President. The Secretary-Treasurer gave an interim statement and explained that under the revised constitution, the annual financial statement would not be available until early in January, 1961. Directors for 1961: The Secretary read the list resulting from the mail ballot conducted during the past year. As no further nominations were forthcoming the following were declared elected to the Board of Directors for the season 1961: W. E. Beckel, Toronto D. M. Davies, Hamilton E. C. Becker, Ottawa M. L. Prebble, Ottawa Joan F. Bronskill, Belleville H. B. Wressell, Chatham J. MacB. Cameron, S. S. Marie Annual Meeting 1961: An invitation by D. M. Davies, that the next Annual Meeting be held at McMaster University, Hamilton, Ontario in the late fall of 1961 was unanimously accepted. New Business: Centennial 1963: It was moved and seconded by Messrs. Manson and West that the 1963 meeting be held in Guelph and that the Entomological Society of Ontario invite the Entomo- logical Society of Canada to meet with us and celebrate the anniversary of one hundred years of entomology in Canada. This motion was unanimously approved. 275 The President suggested that the incoming board be asked to consider the in- vitations. Prof. A. W. Baker explained that the original collections of the Society had many unusual varieties and these had been placed in the National Collection at Ottawa many years ago. Prof. Baker then expressed a vote of thanks to the out- going board of directors. This was heartily endorsed by Mr. L. A. Miller who remarked on the fine quality of the papers presented and in the interesting panel on Wildlife. While commenting on the lack of papers on insect control he thanked the programme committee for its efforts. Auditors: On a motion by Messrs. Beckel and Dixon, C. Payton and B. Clarkson were appointed as auditors for the coming year. The President then expressed appreciation for the accommodation provided by the Ontario Agricultural College and as no further business was brought up declared the meeting adjourned at 12:28 p.m. W. C. Allan, December 30, 1960. Secretary, Treasurer, ENTOMOLOGICAL SOCIETY OF ONTARIO Guelph, Ontario, Canada FINANCIAL STATEMENT 1959 - 1960 RECEIPTS EXPENDITURES HD) eS ee dun ek eae $1,745.42 1.: Dues: to Can: Ent. 3372 $1,318.00 2) Proceedings)... fsa 6.95 2.) Hxchange \o.\.4....2 11.34 CSU) Be 0) tl OTC SURNAM ak SS ed oO 209.38 8. Bank charges: 2)... ose 1.57 As IN Cerest ists eens nee yee One 15.80 4, Library—Honorarium ........ 100.00 Be | Gramusy! wiles HW OS as 300.00 5, Bindine: 00 eee 4.05 6. ‘Bank< Credit. 202) 2 eee 7.53 6. Postage and Express ........ 195.51 7. Miscellaneous _....................... 8.00 4..- Printinge—FEorms) =e Lie10 (payment on N.S.F. cheque) 8. Printing—Reprints ............ 127.50 9: Ballots?) 0.0.42... 3 39.55 10. Envelopes and Wrappers .. 138.48 11. Clerical Assistance ............ 52.00 12: Auditors) 34550 ee 5.00 13." Stamp “Pads.*7) 37323 5.50 14. Grant to Ent. Soe. Gan? 7.77 425.00 15. Grant to Zool. Record ........ 100.00 16; Banquet Permit 7 10.00 17. Committee Badges ............ oil 18. Library Insurance ............ 25.00 $2,293.08 $2,287.83 Bank Balance 1 November 1959 811.19 Bank Balance 31 December 1960 816.44 $3,104.27 $3,104.27 Bonds 1 November 1959 ............. $ 400.00 Bonds 31 December 1960 .......... $ 400.00 Auditors W. C. Allan, C. J. Payton Secretary-Treasurer, B. D. Clarkson 31 December, 1960. REPORT OF THE COMMITTEE ON COMMON NAMES OF INSECTS This report covers the Committee’s activities during both 1959 and 1960 as no report was submitted last year. Neither was the committee able to get together as the chairman was the only member present at the joint meetings held in Detroit. During the two-year period the committee continued to be active in the submission of common name proposals. proposed: Myzocallidium riehmi Borner Altica ulmi Woods In 1959 the following two names were sweetclover aphid elm flea beetle It was later discovered that the name sweetclover aphid had already been proposed in the United States and that proposal was therefore withdrawn. During the past year the following five names were submitted for consideration: Musca autumnalis L. — cattle face fly Ixodes cookei (Pack.) — northeastern woods tick Franklhiniella vacciniu Morgan -— blueberry thrips Cnephasia virgaureana Treit. — omnivorous webworm Pegomya betae (Curtis) _— beet leaf miner Correspondence on common names committee business amounted to some twenty letters. Considerable time was spent searching entomological literature for supporting data relative to name proposals; and officers of systematic entomology kindly sup- plied pertinent information on several occasions. November 20, 1960. N.* W. Y. Watson, Sault Ste. Marie W. W. Judd, London L. A. Miller, Toronto C. G. MacNay, Ottawa, Chairman REPORT OF THE LIBRARY COMMITTEE In 1960 this Committee did not enact any new business as it was not considered advisable to increase the responsibilities of the Library in view of the proposed move from its present location. All exchanges were kept up to date and requests for new exchanges were postponed until a more appropriate time. During the past year many publications were sent out on Library Loan Requests and it is obvious that the Library has a very valuable place in this respect. Preliminary plans for a move have been discussed but nothing definite can be done until a final agreement has been drawn up between the Society and the Ontario Agricultural College. November 20, 1960. A. A. Kingscote, Guelph B. V. Peterson, Guelph J. H. H. Phillips, Vineland Station W. C. Allan, Guelph, Chairman REPORT OF THE PUBLICATIONS COMMITTEE The Committee was responsible, constitutionally, for two publications, that is, the Society’s annual report to the Minister of Agriculture for Ontario, and The Canadian Entomologist. The Committee devoted its entire attention to the report to the Minister. Although the Society and the Entomological Society of Canada have been joint publishers of The Canadian Entomologist since 1950, our Society has not participated in the preparation of this journal in recent years. The Society’s responsibility for the journal was abrogated in 1960 in the revision of the agree- ment between the two Societies, whereby, the Entomological Society of Canada became sole publisher. The Society is required to submit to the Minister an annual report of its pro- ceedings and “such general information on matters of special interest to the Society as the Society has been able to obtain”. This submission has been published, since its inception, as the “Annual Report of the Entomological Society of Ontario”. By direction of the Board of Directors, the report for 1959 was entitled “Proceedings of the Entomological Society of Ontario’. The Committee recommends that the use of the new title be continued. Volume 90 of the Proceedings contained eight submitted papers, four scientific notes, a review of important insect infestations and occurrences, the proceedings of the 96th annual meeting, and the financial statement for 1958-1959. A statement of publication policy, as well as rules for the preparation of manuscripts was pre- pared by the Committee and included in the Proceedings for the guidance of mem- bers and authors. The Proceedings were published by authority of the Minister in September, 1960, two months in advance of the publication dates of recent years. The Committee acted as an Editorial Board for the Proceedings, with the Chairman as Editor, as required by the Constitution. It considered all papers that were submitted for publication in the Proceedings, as well as the comments of reviewers to whom the majority of the papers were referred. A few manuscripts were accepted as received; the majority were accepted after revision by the authors; and one manuscript was rejected. 277 The Committee, with the approval of the Board of Directors, initiated a policy of inviting four members of the Society to submit papers on insects or related groups of insects of economic importance in Ontario, or of general entomological interest. These papers are to be submitted for publication in Volume 91 of the Proceedings. The Committee recommends that the policy should be a continuing one, since reviews of this type will provide valuable information for the membership, and contribute to the practise of agriculture and forestry in Ontario. It is the opinion of the Committee that the recent establishment of higher standards for manuscripts accepted for publication in the Proceedings, as well as the appointment of an Editorial Board, have led to a significant improvement in the Proceedings. Continued and additional efforts in this direction will be required by future committees to develop a scientific publication of the highest repute. November 22, 1960. D. M. Davies, Hamilton G. R. Manson, Chatham D. G. Peterson, Guelph, Chairman THE PRESIDENT’S PRIZE The Executive Committee of the Entomological Society of Ontario wishes to announce that an award of fifty dollars will be given to a graduate or undergraduate student in Ontario presenting the best paper, of high standard, at the next, and each subsequent, annual meeting of the Society. It is hoped that in this way more students will be encouraged into an active study of insects and a closer associa- tion with the Society. January 12, 1961. Douglas M. Davies, President NOMINATION OF FELLOWS The new 1960 constitution enables the Entomological Society of Ontario to honour persons, who have made an outstanding contribution to the advancement of ento- mology, by electing them as fellows of the Society. This note is to encourage members to nominate persons whom they consider worthy of this honour. The method of nomination and election is clearly stated in section 14 of the By-Laws of the new Constitution as follows: “Fellows shall be elected by two-thirds of the votes cast in a secret mail vote by the members of the Society. (1) A person may be nominated as a fellow by not less than three members of the Society in good standing. (2) Nominations shall be delivered in writing to the Secretary at the annual meeting. (3) Nominations received by the secretary and approved by two-thirds of the votes at a meeting of the board of directors shall be placed on a ballot prepared by the secretary and mailed to the members with the ballot for the election of directors. (4) The ballots shall be returned to the Secretary not later than the fifteenth day of July and shall be opened and counted at the same time and under the same scrutiny as the ballots for the election of directors. (5) The Secretary shall announce at the annual meeting the names of the persons elected as fellows.” It might be mentioned at this time that Honorary Memberships and Life Member- ships accepted prior to the 1960 Constitution still stand but that ‘no person shall be accepted into honorary life membership in the Society after the coming into force of these by-laws’’. There are several persons worthy of being fellows of this Society and it is hoped that a number of nominations will be submitted to the secretary, Dr. C. C. Steward. February 28, 1961. Douglas M. Davies, President 278 ALFRED BRIGGS BAIRD, 1891-1960 Alfred Briggs Baird, a pioneer entomologist and earnest architect of biological control in Canada, who was born in Lake Stream, N.B., on October 11, 1891, died in Ottawa on September 17, 1960. Mr. Baird’s primary education began at Lloyd’s schoolhouse near Chipman, N.B. He later attended the Chipman High School, matriculating to the Nova Scotia Agricultural College at Truro, where he com- pleted the two-year course in 1910. After spending several seasons scouting for insect pests for the Division of Entomology, though most of the scouting was done on foot, he entered the Ontario Agricultural College at Guelph to study entomology, graduating with a B.S.A. in 1916. In the autumn of 1920 he enrolled in graduate studies at Cornell University on a Carnegie scholarship and received the M.S. degree the following spring. Mr. Baird’s entomological career began in 1911 with his appointment as a seasonal assistant to Mr. G. Sanders on the brown-tail moth survey and eradication program in the Maritimes. During the summer, from 1912 until he entered the Ontario Agricultural College, he worked under Dr. J. D. Tothill in the first entomological laboratory in New Brunswick, on the campus of the University of New Brunswick at Fredericton. This later became the first biological control investigation centre in Canada. After graduation from university in 1916 he was appointed field officer at Fredericton, where he continued working with Dr. Tothill on parasite intro- ductions and the natural control of native pest insects. These studies were extended to the Western Provinces in 1917, and in 1918 Mr. Baird was transferred to British Columbia with headquarters at Agassiz. During this period he did extensive research on the natural control of the spruce budworm, the fall webworm, tent caterpillars, and the oak looper, all under rather primitive conditions and many with harrowing experiences. On his first trip to the budworm-infested area at Lillooet, B.C., he was mistaken for a revenue officer and for protection had to spend most of the night hidden behind the counter of the general store. May this have engendered his great love of the outdoors, especially the higher elevations of the mountains of British Columbia? In 1921, after attending Cornell University, he was transferred to Fredericton to study the parasites of the larch sawfly and the larch casebearer, preparatory to the introduction of natural enemies from England. With the reorganization of the Fredericton laboratory in 1923, Mr. Baird was transferred to Ottawa to work on parasitic Hymenoptera in the Canadian National Collection of Insects. Soon he was 279 transferred again, this time to the Division of Foreign Pests Suppression to arrange for the introduction of parasites of the European corn borer, with headquarters in two rooms of his home at St. Thomas, Ont. In 1925 the work was transferred to Chatham, Ont., where, during the next few years, the program was expanded to include studies on the oriental fruit moth, the European earwig, the greenhouse whitefly, and certain other pest insects. A permanent laboratory and headquarters for biological control work, with Mr. Baird in charge, were established at Belleville, Ont., in 1929. Under his direction the activities of the laboratory expanded rapidly, and with the discovery of the European sawfly in Quebec in 1930 many more species of beneficial insects were brought to Canada from abroad. Through Mr. Baird’s foresight and ingenuity the first air-conditioned laboratory in the Division was built at Belleville in 1934 for rearing and handling insects in quarantine. In this building some 100 million parasites have been propagated for distribution throughout Canada. In 1948, other biological control laboratories were established in Quebec and British Columbia and Mr. Baird was transferred to Ottawa -as head of the Biological Control Unit, where he remained until his retirement in 1956. As a pioneer, and as a leader for over 40 years in the biological method of insect control in Canada, Mr. Baird never lost sight of the applied interests of his profession and to this end he maintained and greatly expanded the work started by Dr. Tothill. He had the great distinction of organizing and directing biological control work in Canada during its period of greatest growth, and most of it through the economic depression of the ’30’s and the period of difficult staff problems of the Second World War. He had a great influence on the development of applied entomology in the Division and contributed much to its recognition abroad. He represented the Division at the Commonwealth Conference on Entomology in 1948 and 1954, and was twice an official delegate at the Pacific. Science Congress. He was president of the Entomological Society of Ontario in 1945-1947, a charter member of the Agricultural Institute of Canada and the Professional Institute of the Civil Service, and treasurer of the Entomological Society of Canada from 1951 to 1954. He served as treasurer and member of the executive committee for the Tenth International Congress of Entomology at Montreal in 1956. While at the Ontario Agricultural College, Mr. Baird met Hazel A. Black of Guelph, Ont. They were married in April, 1926, and had three children: a daughter, Barbara (Mrs. D. H. Buchanan) now in Ottawa, and two sons, Ronald in Belleville, and Haddow, an officer lost with H.M.C.S. Shawinigan during the Second World War. —A. Wilkes JAMES HERBERT FOLLWELL, 1914-1960 Jim Follwell was born in Belleville, Ontario, on September 23, 1914. He died on June 16, 1960, after a prolonged illness. He attended public and high school in Belleville and received his B.S.A. degree from Ontario Agricultural College in 1940. In 1943 he received the degree of M.S.A. from the University of Toronto. Mr. Follwell served as a Flight Lieutenant in the R.C.A.F. in Canada and Iceland for a period of three years. Following demobilization, he was Supervisor of aches from 1945 to 1949 at the University of Toronto, at both Toronto and jax. Mr. Follwell was employed in the Entomology Division at the Belleville laboratory as a Student Assistant during the summers of 1940 to 1942. In May, 1949, he joined the staff of the Stored Product Insect Investigations at Ottawa. In October of the same year he was transferred to Vancouver, B.C., to open the stored product insect laboratory there. While in Vancouver much of his time was devoted to a study of the life-history and biology of the spider beetles of that area. He pub- lished a paper “Notes on Some Ptinidae of British Columbia (Coleoptera)” in the Proceedings of the Entomological Society of British Columbia (1951) Vol. 48. August 15, 1952. Mr. Follwell returned to Ottawa in January, 1952 to pursue full-time research on insect pests of stored grain. Early in 1952 he completed a publication in co-operation with the Department of Agriculture of the Province of British Columbia, entitled “Stored Product Insects and Their Control in British Columbia”. Jim was an excellent athlete. He played football for O.A.C. and for the Toronto Argos, later serving as an assistant coach for the Varsity Blues. While in Van- couver he coached the Meralomas to a junior provincial championship. After his return to Ottawa he assisted in the coaching of football at Ashbury College. He was also very much interested in choir and choral music. For a number of years he was also a member of the Belleville Municipal Band. 280 His cheery disposition and even temperament made him an admirable travelling companion. All who knew him well have experienced a real loss in his passing. Jim is survived by his wife, Lois; one daughter, Janet Lee; four brothers and one sister. —H. EH. Gray HUGH MacINTOSH THOMSON, 1926-1960 Hugh Thomson died on September 10 at Ottawa. He had Hodgkin’s disease for five years, and during his illness he gained the admiration of his colleagues for his unfailing courage and his determination to carry on with his work. Hugh was born at Perth, Ont., on January 28, 1926. He entered McGIll Uni- versity in 1944, served in the Army from June to September, 1945, and then com- pleted his undergraduate work, receiving his B.Sc. degree in bacteriology and zoology in 1948. Also at McGill, he obtained his M.Se. in 1951 and his PhD., majoring in parasitology, in 1957. He joined the staff of the Forest Insect Laboratory, Sault Ste. Marie, as a Student Assistant in 1947, and on full time after graduation in 1948. He began studies on the pathology of the spruce budworm in 1949, and later special- ized on the protozoa associated with this and other insects. In 1954 he was trans- ferred to the Laboratory of Insect Pathology, and in 1960 to the Entomology Research Institute in Ottawa. In these few years Hugh gained an international reputation as an insect protozoologist, and only a few weeks ago he had a com- prehensive check list of the microsporidia affecting insects accepted for publica- tion in the Journal of Insect Pathology. Hugh was a member of the Entomological Society of Canada, the Entomo- logical Society of Ontario, the Society of American Parasitologists, the Canadian Society of Microbiology, Sigma Xi (McGill Chapter), and the Professional Institute of the Public Service of Canada. He was an enthusiastic and skilled photographer, was an active’skier before his illness, and was very fond of music. His other inter- ests included gardening and coin collecting. He is survived by his wife, formerly Mary MacLeod of New Glasgow, N-.S., and Macdonald College, and one son, Bruce, age 5. —J. M. Cameron 281 ENTOMOLOGICAL SOCIETY OF ONTARIO MEMBERSHIP LIST 1961 Members are requested to check their addresses on this list. The Secretary- Treasurer will be grateful for all errors and omissions brought to his attention. HONORARY MEMBERS The Minister of Agriculture for Ontario. W. R. Thompson, Commonwealth Institute for Biological Control, K. W. Neatby Building, Carling Avenue, Ottawa. E. M. Walker, Royal Ontario Museum, Toronto, Ont. MEMBERS W. C. Allan, Dept. of Zoology, O.A.C., Guelph, Ont. D. C. Anderson, Forest Insect Laboratory, Box 490, Sault Ste. Marie, Ont. T. A. Angus, Forest Biology Laboratory, Box 490, Sault Ste. Marie, Ont. T. Armstrong, Research Laboratory, Research Branch, Vineland Station, Ont. A. P. Arnason, Program Directorate, Research Branch, Canadian Agriculture, Ottawa. J. W. Anold, Entomology Research Institute, Canada Agriculture, Ottawa. A. P. Arthur, Entomology Research Institute, Box 367, Belleville, Ont. C. E. Atwood, Dept. of Zoology, University of Toronto, Toronto 5, Ont. A. D. Baker, Entomology Research Institute, Canada Agriculture, Ottawa. A. W. Baker, Cedarhurst, Beaverton, Ont. W. F. Baldwin, Atomic Energy of Canada, Chalk River, Ont. C. A. Barlow, Entomology Laboratory, Box 488, Chatham, Ont. W. E. Beckel, Dept. of Zoology, University of Toronto, Toronto 5, Ont. E. C. Becker, Entomology Research Institute, Canada Agriculture, Ottawa. A. Begg, Entomology Laboratory, Box 488, Chatham, Ont. . P. Beirne, Entomology Research Institute, Box 367, Belleville, Ont. D: Bennett, Imperial College of Tropical Agriculture, St. Augustine, panes B.W.I. A. Berlin, Dept. of Entomology, Purdue University, Lafayette, Ind., A. A.. CG. Berube, Entomology Research Institute, Box 367, Belleville, Ont. . T. Bird, Insect Pathology Research Institute, Box 490, Sault Ste. Marie, Ont. ae Bond, Pesticide Research Institute, University Sub Post Office, London, Ont. ee Borgatti, Entomology Dept., Michigan State University, East Lansing, Mich., U.S.A H. R. Boyce, Research Station, Research Branch, Harrow, Ont. J. F. Brimley, Wellington, Ont. Miss Joan F. Bronskill, Entomology Research Institute, Box 367, Belleville, Ont. A. W. A. Brown, Dept. of Zoology, University of Western Ontario, London, Ont. W. J. Brown, Entomology Research Institute, Canada Agriculture, Ottawa. P. I. Bryce, Box 210, Vineland, Ont. G. E. Bucher, Entomology Research Institute, Box 367, Belleville, Ont. L. Burgess, Dept. of Biology, University of Saskatchewan, Saskatoon, Sask. T. Burnett, Entomology Research Institute, Box 367, Belleville, Ont. C. S. Burton, 86 Nelson Street, Kingston, Ont. J. W. Busch, Niagara Brand Chemicals, Burlington, Ont. 1. ee Cameron, Insect Pathology Research Institute, Box 490, Sault Ste. Marie, t 3 He) a lreale3 lee) oo nt. I. M. Campbell, Forest Insect Laboratory, Box 490, Sault Ste. Marie, Ont. L. M. Cass, Entomology Research Institute, Canada Agriculture, Ottawa. D. A. Chant, Research Laboratory, Research Branch, Vineland Station, Ont. J. G. Chilleott, Entomology Research Institute, Canada Agriculture, Ottawa. L. N. Chiykowski, Plant Research Institute, Canada Agriculture, Ottawa. G. S. Cooper, 482 Atwater Avenue, Port Credit, Ont. C. Copeland, Plant Protection Office, Room 21, 98 Fleet St. E., Toronto, Ont. H. C. Coppel, College of Agriculture, University ‘of Wisconsin, Madison 6, Wis., U.S.A. J. F. Coyne, Box 151, Gulfport, Miss., U.S.A. Miss. I: S. Creelman, Scientific Information Section, Research Branch, Canada Agriculture, Ottawa. D. M. Davies, Dept. of Zoology, McMaster University, Hamilton, Ont. L. Davies, Dept. of Zoology, Science Laboratories, South Road, Durham, England. 282 er ee > Sy Ob Ha aun . F. Davis, Stored Product Insect Laboratory, U.S.D.A., Box 3034, Station A, Savannah, Georgia, U.S.A. . D. Dever, Box 230, Medina, N.Y., U.S.A. E. Dixon, Dept. of Zoology, O.A.C., Guelph, Ont A. Downes, Entomology Research Institute, Canada Agriculture, Ottawa. . G. Dustan, Research Laboratory, Research Branch, Vineland Station, Ont. . C. Eickwort, Entomology Dept., Michigan State University, East Lansing, Mich. R. Elliott, Forest Entomology Laboratory, Box 6300, Winnipeg, Man. . Murray Fallis, Ontario Research Foundation, 43-47 Queen’s Park, Toronto 5, Ont. W. Farstad, Production and Marketing Branch, Plant Protection Division, Canada Agriculture, Ottawa. G. Fast, R.R. 3, Ilderton, Ont. J. Fettes, Forest Entomology and Pathology Branch, 238 Sparks St., Ottawa. Mrs. L. R. Finlayson, Entomology Research Institute, Box 367, Belleville, Ont. R. W. Fisher, Research Laboratory, Research Branch, Vineland Station, Ont. E. W. Fletcher, Dow Chemical Co., Midland, Mich., U.S.A. W. H. Foott, Research Station, Canada Dept. of Agriculture, Harrow, Ont. W. A. Fowler, Production and Marketing Branch, Plant Protection Division, Canada Agriculture, Ottawa. T. N. Freeman, Entomology Research Institute, Canada Agriculture, Ottawa. W. G. Friend, Dept. of Zoology, University of Toronto, Toronto 5, Ont. B. Furgala, Entomology Research Institute, Canada Agriculture, Ottawa. L. Gardiner, Forest Insect Laboratory, Box 490, Sault Ste. Marie, Ont. J. J. R. Gates, 149 Sunnyside, Chatham, Ont. A. George, Research Laboratory, Box 596, St. Catharines, Ont. Robert Glen, Director General, Research Branch, Canada Agriculture, Ottawa. H A D H . W. Goble, Dept. of Zoology, O.A.C., Guelph, Ont. . R. Graham, Entomology Research Institute, Box 367, Belleville, Ont. . E. Gray, Forest Entomology and Pathology Branch, 238 Sparks St., Ottawa. . E. Gray, Entomology Research Institute, Canada Agriculture, Ottawa. G. W. Green, Forest Insect Laboratory, Box 490, Sault Ste. Marie, Ont. *F. W. Gregory, Box 34, Niagara Falls, Ont. K J. . J. Griffiths, Forest Biology Laboratory, Box 490, Sault Ste. Marie, Ont. C. Guppy, Entomology Research Institute, Canada Agriculture, Ottawa. Miss J. M. Gustafson, Entomology Research Institute, Canada Agriculture, Ottawa. C. Guyer, Dept. of Entomology, Michigan State University, East Lansing, Mich. W. O. Haberman, Ralston Purina Co., Checkerboard Sq., St. Louis 2, Miss., U.S.A. W. Haliburton, Forest Entomology and Pathology Branch, 238 Sparks St., Ottawa. *A. R. Hall, The House that Jack Built, R.R. 4, Oshawa, Ont. SPASWOOOA 4 . R. Hall, Dept. National Health and Welfare, Laboratory of Hygiene, Ottawa. . G. Harcourt, Entomology Research Institute, Canada Agriculture, Ottawa. . F. Hardwick, Entomology Research Institute, Canada Agriculture, Ottawa. . R. Harris, Entomology Laboratory, Box 488, Chatham, Ont. . Harris, Entomology Research Institute, Box 367, Belleville, Ont. B. Hartley, 1199 Woodside Drive, Ottawa 3. . T. Harvey, Forest Insect Laboratory, Box 490, Sault Ste. Marie, Ont. . M. Heimpel, Insect Pathology Laboratory, Entomology Bldg. A, ARC, Beltsville, Md., U.S.A. . E. Heming, Dept. of Zoology, O.A.C., Guelph, Ont. V. E. Henderson, Entomology Research Institute, Canada Agriculture, Ottawa. W. R. Henson, Osborn Zoological Laboratory, Yale University, New Haven, Conn. H. Herdy, Forest Insect Laboratory, Box 490, Sault Ste. Marie, Ont. D . C. Herne, Research Laboratory, Research Branch, Vineland Station, Ont. A. Hikichi, Entomology Substation, Box 458, Simcoe, Ont. G. P. Holland, Entomology Research Institute, Canada Agriculture, Ottawa. C . 8. Holling, Forest Insect Laboratory, Box 490, Sault Ste. Marie, Ont. H. L. House, Entomology Research Institute, Box 367, Belleville, Ont. C . Y. Hovey, 2151 Skinner Street, Niagara Falls, Ont. H. F. Howden, Entomology Research Institute, Canada Agriculture, Ottawa. A. J. Howitt, Dept. of Entomology, Michigan State University, East Lansing, Mich. Miss Anne Hudson, Entomology Research Institute, Canada Agriculture, Ottawa. F . J. Hudson, Dept. of Agriculture, Box 325, London, Ont. *H. F. Hudson, 93 Oxford St., London, Ont. H. Hurtig, Program Directorate, Research Branch, Canada Agriculture, Ottawa. F. P. Ide, Dept. of Zoology, University of Toronto, Toronto 5, Ont. C. Jackson, Entomology Research Institute, Canada Agriculture, Ottawa. H. G. James, Entomology Research Institute, Box 367, Belleville, Ont. 283 A. C. Jones, Room 3539, “A” Building, Dept. of National Defence, Ottawa. W. W. Judd, Dept. of Zoology, University of Western Ontario, London, ‘Ont. J. Juillet, Entomology Research Institute, Box 367, Belleville, Ont. H. Katz, 2039 Fifth Avenue, Pittsburgh 19, Pa., U.S.A. L. A. Kelton, Entomology Research Institute, Canada Agriculture, Ottane C. S. Kirby, Laboratory of Forest Pathology, Southern Research Station, Maple, Ont. A. Kune, Gunnar Uranium Mines, Uranium City, Sask. Ray Lapp, Room 507, Canada Bldg., Windsor, Ont. K. Leius, Entomology Research Institute, Box 367, Belleville, Ont. O. H. Lindquist, Forest Insect Laboratory, Box 490, Sault Ste. Marie, Ont. I. Lindsay, Defence Research Board, N.D.H.A., Ottawa. L. A. Lyons, Forest Insect Laboratory, Box 490, Sault Ste. Marie, Ont. — G. F. Manson, Entomology Laboratory, Box 488, Chatham, Ont. Jj. Ki. Hi. Martin, Entomology Research Institute, Canada Agriculture, Ot J. L. Martin, Forest Insect Laboratory, Box 490, Sault Ste. Marie, Ont. ibe ae Martin, c/o Dow Chemical Co., Sarnia, Ont. . M. Mason, Entomology Research Institute, Canada Agriculture, Ottawa. Matthewman, Entomology Research Institute, Canada Agriculture, Ottawa. — Maw, Entomology Research Institute, Box 367, Belleville, Ont. F. Miller, Entomology Research Institute, Canada Agriculture, Ottawa. A. Miller, Shell Oil Co. of Canada, 505 University Avenue, Toronto, Ont. eee anGr. . G. aD. oyd - Milliron, Entomology Research Institute, Canada Agriculture, Ottawa. 12 G. E. Le rs U. Monro, Pesticide Research Institute, Research Branch, University Sub ost Office, London, Ont. Monteith, Entomology Research Institute, Box 367, Belleville, Ont. Morrison, 341 Metcalfe St., Guelph, Ont. ugene Munroe, Entomology Research Institute, Canada Agriculture, Ottawa. . J. Musgrave, Dept. of Zoology, O.A.C., Guelph, Ont. F. McAlpine, Entomology Research institute, Canada Agriculture, Ottawa. ‘C. a McNay, Scientific Information Section, Research Branch, Canada Agriculture, ttawa. R. McClanahan, 6 Detroit Drive, Chatham, Ont. B. M. McGugan, Forest Entomology and Pathology Branch, Dept. of Forestry, - 238 Sparks St., Ottawa. Miss M. MacKay, Entomology Research Institute, Canada Agriculture, Ottawa. W. S. McLeod, Supervisor, Pesticide Unit, Room 730, Confederation Bldg., Ottawa. J. J. R. McLintock, Entomology Research Institute, Canada Agriculture, Ottawa. P. W. McMullen, Fisons (Canada) Ltd., 18983 Davenport Road, Toronto, Ont. A. G. McNally, Dept. of Zoology, O.A.C., Guelph, Ont. H. H. J. Nesbitt, Carleton College, Ottawa. J. A. Oakley, 267 Weldon Avenue, Oakville, Ont. *R. H. Ozburn, Dept. of Zoology, O.A.C., Guelph, Ont. V. Paxton, 40 Chopin Avenue, Scarborough, Ont. F. S. Pearse, AgroSpray Chemicals, 560 Exmouth St., Sarnia, Ont. L. L. Pechuman, 7 Davison Rd., Lockport, N.Y., U.S.A. O. Peck, Entomology Research Institute, Canada Agriculture, Ottawa. D. H. Pengelly, Dept. of Zoology, O.A.C., Guelph, Ont. B. V. Peterson, Entomology Laboratory, Box 248, Guelph, Ont. DEG: Peterson, Entomology Laboratory, Box 248, Guelph, Ont. J. H. H. Phillips, Research Laboratory, Research Branch, Vineland Station, (Ont P. J. Pointing, Forest Insect Laboratory, Box 490, Sault Ste. Marie, Ont. M. i Prebble, Entomology and Pathology Branch, Dept. of Forestry, 238 Sparks St., ttawa. W. L. Putman, Research Laboratory, Research Branch, Vance’ Station, Ont. A. a Randall, Entomology and Pathology Branch, Dept. of Forestry, 238 Sparks St., ttawa. L. L. Reed, Plant Protection Division, Canada Agriculture, Ottawa. W. A. Reeks, Forest Insect Laboratory, Box 490, Sault Ste. Marie, Ont. H. M. meces Jr., c/o Union Carbide Canada Ltd., P.O. Box 700, Point aux ‘Trembles, alas | Heewe eae Rice, Dept. of Mines, Ottawa. W. R. Richards, Entomology Research Institute, Canada Agriculture, Ouanen Rev. Jules C. Riotte, Director, Diocesan Church Cong., 278 Bathurst St., Toronto, Ont. I. Rivard, Entomology Research Institute, Box 367, Belleville, Ont. ecA. iO: Roadhouse, Scientific Information Section, Research Branch, Canada Agriculture, Ottawa. 284 J. G. Robertson, Entomology Research Institute, Canada Agriculture, Ottawa. J. G. Rodriguez, Entomology Dept., University of Kentucky, Lexington, Ky. A. H. Rose, Forest Insect Laboratory, Box 490, Sault Ste. Marie, Ont. H. E. Ryder, 149 James St. N., Hamilton, Ont. Miss Helen Salkeld, Entomology Research Institute, Canada Agriculture, Ottawa. pie K SCoL, 29 Lumar Road, Trenton 8, N.J., U.S.A M. Semel, L. I. Vegetable Research Farm, Riverhead, NoYes US AS ITs Sharp, Entomology Research Institute, Canada Agriculture, Ottawa. G. E. Shewell, Entomology Research Institute, Canada Agriculture, Ottawa. F. J. Simonds, Entomology Research Institute, Canada Agriculture, Ottawa. W. L. Sippell, Forest Insect Laboratory, Box 490, Sault Ste. Marie, Ont.: B. N. Smallman, Program Directorate, Research Branch, Canada Agriculture, Ottawa. E. P. Smereka, Forest Insect Laboratory, Box 490, Sault Ste. Marie, Ont. B. C. Smith, Entomology Research ae Box 367, Belleville, Ont. H. J. Smith, Box 310, Sackville, N.B J. Morris Smith, Entomology Research Institute, Box 367, Belleville, Ont. Miss L. K. Smith, Entomology Research Institute, Canada Agriculture, Ottawa. R. W. Smith, Entomology Research Institute, Box 367, Belleville, Ont. S. G. Smith, Forest Insect Laboratory, Box 490, Sault Ste. Marie, Ont. R. Snetsinger, Dept. of Zoology and Entomology, Pennsylvania State University, University Park, Penna. G. R. Stairs, Forest Insect Laboratory, Box 490, Sault Ste. Marie, Ont. A. W. Steffan, Max-Planck Institut fiir Meeresbiologie, Wilhelmshaven, Germany. Miss June M. Stephens, Dept. of Bacteriology, London School of Hygiene and Tropical Medicine, Keppel St., London W.C.1., England. . B. Stevenson, Research Laboratory, Research Branch, ay Station, Ont. C. Steward, Entomology Laboratory, Box 248, Guelph, R. Sullivan, Forest Insect Laboratory, Box 490, Sault oe Pees Ont. A. Swan, 530 Mt. Vernon Blvd., Royal Oak, Mich., U.S.A. D. Syme, Dept of Zoology, University of Toronto, Toronto 5, Ont H. J. Teskey, Entomology Laboratory, Box 248, Guelph, Ont. J. B. Thomas, Forest Insect Laboratory, Box 490, Sault Ste. Marie, Ont. *M. G. Thomson, 2226 West 35th Avenue, Vancouver, B.C. F. Townsend, Apiculture Department, O.A.C., Guelph, Ont. Troyer, Troyer Natural Science Service, Oakridges, Ont. . Upitis, Pesticide Research Institute, University Sub Post Office, London, Ont. A. Urquhart, 1389 Military Trail, West Hill, Ont. R. Vockeroth, Entomology .Research Institute, Canada Agriculture, Ottawa. . Wagner, 5 Victoria St., Elmira, Ont. . R. Wallace, Forest Insect Laboratory, Box 490, Sault Ste. Marie, Ont. S. Walley, Entomology Research Institute, Canada Agriculture, Ottawa. . W. Walsh, Box 68, Harrow, Ont. B. Watson, Entomology Research Institute, Canada Agriculture, Ottawa. . Y. Watson, Dept. of Biology, Laurentian University, Elgin St., Sudbury, Ont. EK. Welch, Entomology Research Institute, Box 367, Belleville, One. G. Wellington, 409 Federal Building, Victoria, B.C. S. West, Dept. of Zoology, Queen’s University, Kingston, Ont. B. Wiggins, Royal Ontario Museum, Toronto 5, Ont. ee Scientific Information Section, Research Branch, Canada Agriculture, tawa Wilkes, Entomology Research Institute, Canada Agriculture, Ottawa. C. Wilkinson, Agricultural Experimental Station, University of Florida, Gainsville, Fla. E. Winmill, 1262 Erindale Dr., Ottawa 3. Wishart, Entomology Research Institute, Box 367, Belleville, Ont. M. Wood, 7 Dale Ave., Toronto, Ont. B. Wressell, Entomology Laboratory, Box 488, Chatham, Ont. G. Wylie, Entomology Research Institute, Box 367, Belleville, Ont. E. Yunker, c/o M.A.R.W., Box 2011, Balboa Hts., Canal Zone. WHOOp QHEUQ> Bb WObdRSEROD RY ae me ASSOCIATE MEMBERS B. Hocking, Dept. of Entomology, University of Alberta, Edmonton, Alta. W.N. ene Plant Prot. Div., Prod. and Marketing Branch, Canada Agriculture, Ottaw RW aisso sedi 1805 Mouland Avenue, Niagara Falls, Ont. *Life Member Guelph, 14th August, 1961. 285 INDEX (The summary by C. G. MacNay, pp. 247-263, is not included in this Index.) A (4 AP LEO RIAS BIR D9 IS SSE a reg ce Rice A EN aR CI OP ee 26 woodi, cause of Isle of Wight GTSCASE Pee hn ea ee, ae Gy eae Meee: oe 25 Acyrthosiphon pisum, nutritional disease and control .............. eee etcetera 18 Adopaea lineola (see Thymelicus lineola) ie CONG GOic © Wibe EI OT SP ECIOS) force eS) ics scest oa es Sat odes tenes cdehc bak sede erates ngs Meaedeoabovestsseonaauene 137 Reena AN et TC EAE Yc DE OQUCHIG. 55.5. cae sda eee aa TE Rua Jack ocean essere Rik 15 RIVE RCIRE A WALI ENS tia er rae en Ct aaa sae aes Do een otk 17 SUED CPG SCAG CL GLO N eee Ne hs hk EN Sa oat ace as he testing 14 Agria affinis, and chemically-defined iether ea es ee tee en a acl 14 ANd eatehanvecGarDOnVGEALES 1 e0ee.ctsk,. oe me ee eee sc PRES eee ee 15 SILC LAT pe LNDNGS na seek has eekce Sa NG, Mae PL as Erg acer e a so Sat 16 2 PETES. GIRRE GTS CAD Aaa C0 TI eee a ee Soe = rk Nm gee sgt Man eR Eon ae 42 Pama nae, HUT. PALAasitIsM Of Mealy DUG? ..in 0e8) ee ea Ee ee 43 starvation, ‘and disease 223. 0040).. o eee a eee 14 SLone _Drood t4).. Lee ee Se ee a ee 23 stonemywa, keys to Ontario Species: .2.0..0..0.. so...) eine Van 84 Streptococcus :fecalis, and ftoulbrood::. eo ee. ae eee 25 pluton,.and: Toulbrood., |....2..422 5.30. 552 2 eee 25 T Pabanidae, in Ontario See oes ee ae ee Cer 20 nr ee ie (eel te 11 keys to Ontario senera’. 0.040. ea ee eee 82 Tabanus, keys to Ontario species i: .5........-20.0) Bowe ee eee 111 Tenebrio molitor, and dietary lipids ..45....0. a eee 16 and dietary™~ vitamins ..2..8 000.5 ae a eee 16 fhymelicus lineola, description and biology... a ee 189 TEPER, effect .on--wildlife. (32 a ee 43 inhibition ‘of -GhB: 666.2. se ee ee ot toxaphene, ‘control: of :caterpillars on, cabbage -...2.:.)..00 5.5. nike 50 control! of.corn: boreric2.22. ie. ee See pen ieen te Sc eee 244 effect on wildlife .............. I See Re he Bg ok a ak i -Sbs ete Lfribolhum. confusum, and.dietary Vitamins 2.2.5 04.400.1. ee 16 Trichogramma,. parasitism of fruit. moth ege |... 100.64. 223 richoplusia ni control. hu. ee oem." 49 U Uranotacnia sapphirina, description :...40.......os ee a ee eee 130 V Viris,’ diseases in Insects: 2 i 2 vitamins, dietary, effect cof. 6 22 eo eee eee ee 16 Ww wildlife, effect. of insect control ono 3. ee 34 Wycomyia smth, ‘description. 00.52.24 Ss oe he ee 130 af AUTHOR’S GUIDE Volume 90, page (Qs. tio manuscript rules. spondence concerning, and orders for reprints should be addressed to the Md . PROCELLTHNGS LN. Vk OM Wh 0 Gl CAL Volume Ninety-Tue SOCIETY Dea ONVTARK (Published August, 1962) { : i; VAS A PUBLISHED BY AUTHORITY OF Ne THE HONOURABLE WILLIAM A. STEWART, MINISTER OF AGRICULTURE FOR ONTARIO 1 ee AP ; fee) WR ae het, had sty — PROCEELHINGS of the ENTOMOLOGICAL SOCLLTY OF ONTARIO Velume Ninety-TJue $9 67 Published August, 1962 by authority of THE HONOURABLE WILLIAM A. STEWART Minister of Agriculture for Ontario EDITOR D. G. PETERSON, P.O. Box 248, Guelph, Ontario EDITORIAL BOARD D. M. DAVIES, Department of Biology, McMaster University, Hamilton W. G. FRIEND, Department of Zoology, University of Toronto, Toronto ENTOMOLOGICAL SOCIETY OF ONTARIO OFFICERS 1960 - 1961 President: D. M. DAVIES, Hamilton Vice-President : H. B. WRESSELL, Chatham Past President: _. DD. G. PETERSON, Guelph Directors: W. E. BECKEL, Toronto E. C. BECKER, Ottawa JOAN F. BRONSKILL, Belleville J. MAcB. CAMERON, Sault Ste. Marie M. L. PREBBLE, Ottawa Secretary-Treasurer: C. C. STEWARD, Guelph Correspondence about membership in the Society or exchange of publications should be addressed to the Secretary-Treasurer, Dr. C. C. Steward, P.O. Box 248, Guelph, Ontario. CONTENTS VOLUME 92 I. SYMPOSIUM Unconventional Approaches to Insect Control ............. 5 PROVERBS, M. D. Progress on the use of induced sexual sterility for the control of the codling moth, Carpocapsa pomonella (L.) (Lepidoptera ORCC Te MCI Ae) pers te kas me ae ine NIE ct ia Gyn tate Mio ca eee air Ue Ci ies 5 WELCH, H. E. Nematodes as agents for insect control.......................... 11 BELTON, PETER. The physiology of sound reception in insects ......................... 20 a F. L. Control of insects in foodstuffs by high frequency electric UES oe cee Mune Since nce Cena n iiek EGRIE san NR Mea Wom TA iy gaat Cen Lots Panta Cay ts eT 26 Maw, M. G. Some biological effects of atmospheric Plectalcibys ee eae 33 Il. REVIEWS Brcc, J. A. The eastern field wireworm, Limonius agonus (Say) (Coleop- ena swiloteridae). im. southwestern Ontario (1. 2 oe 2 ee 38 Boyce, H. R. Peach tree borers (Lepidoptera : Aegeriidae) in Ontario 45 Il. SUBMITTED PAPERS DAVIES, D. M., B. V. PETERSON and D. M. Woop. The black flies (Diptera : Simuliidae) of Ontario. Part I. Adult identification and distribution with GESCEIP IONS! Ob = Sik, MEW SPeCleSsco 5. oie Oe er a ae ig 70 HANSELL, RoceEr I. C. Prey-capturing methods of spider families as a possible Explonabiony tor. cacin. distributions in Ontario (“hers 2) fe. 2 Se 155 KNERER, G. and C. E. Atwoop. An annotated check list of the non-parasitic Pine ne Ole OnLoad oe pea ae 160 LOUGHTON, B. G. and A. S. WEsT. Serological assessment of spider predation on the spruce budworm, Choristoneura fumiferana (Clem.) (Lepidop- eae mm MO TU IGNCUOLVEN IN Ah Ale rete NC ware ore ig ARE US eS Was Seto gy te A ee HIKICHI, A. Notes on mortality factors affecting the red-banded leaf roller, Argyrotaenia velutinana (Wlkr.), (Lepidoptera : Tortricidae) in an un- Ppkavew apple oreiand in, Ontario ¢ oe em ee ake 180 Hikicu1, A. Some factors influencing the control of the red-banded leaf roller, Argyrotaenia velutinana (Wlkr.), (Lepidoptera : Tortricidae) on pole an. Nortolike County. Ontariog i) ve Se en sa 182 PETERSON, B. V. Observations on mating swarms of Simuliwm venustum (Say) and Simulium vittatum Zetterstedt (Diptera : Simuliidae) ....... 188 ARTHUR, A. P. Adults of the European skipper, Thymelicus lineola (Ochs.) (Lepidoptera : Hesperiidae) trapped in flowers of the showy lady’s slipper ORCAS Las) SAN BE Os Ratan Ae ER a a aa Pa a Irene ne oi aca aaa Wem VO ait aA okie 190 Becec, J. A. Observations on the relationship between tobacco culture and cyclodiene-resistant root maggots, Hylemya spp. (Diptera : Antho- MmynMaae). atcvackine /tlue-cured tobacco.in Ontario o...0.8 2 8 191 Boyce, H. R. Insecticidal activity of maneb formulations against the green- house whitefly, Trialeuwrodes vaporariorum (Westw.) (Hemiptera PHleyrOdLdae) — 24M es, EG NIC aU tae phe care CTA Sana EN Saar sae eg so Cate a 197 Harris, C. R., J. H. MAZUREK and C. V. WHITE. Bioassay of organic insecti- cides, in terms of contact toxicity, to the variegated cutworm, Peridroma sauver, (Hubner), (uepideptera: < Noctuidae) 4 os. ke ee S209 Mazurek, J. H., G. V. WHITE and C. R. Harris. Laboratory tests on the toxicity of some organic insecticides to the boxelder bug, Leptocoris trivit- tats (Say,) (Hemiptera: :Coreidae). en ee ry ek ee AU”: TESKEY, H. J. A method and apparatus for collecting larvae of Tabanidae (Diptera) and other invertebrate inhabitants of wetlands ...........0.00000000... 204 IV. THE SOCIETY Proceedings of the ninety-elehth. annual meeting). ie ee 207 TANCES GCA GI cr UR A SSO Olas a ee i EAA Se REIR Ae Fa 8 Coie nienen nd 207 BUSINESS: IMeebINIG ee re ae TiN Stee Ae Ne ae Cl enetC ey ME ryeah ear ec ahe ore Nal 209 Amendment of thesConstitution and By-laws. .9 026s see eee 210 CoOmMmIMibseen MenObise coe et ee eae Nae ei ee CoN ames eg Seis ee act 211 EZ Tra OS ee oe ees ce aaa ee Ne ONY Wie A Fre eee ue eee a te hela Zale RETO e iy aiter are eee ee one Li ema ts: uc CM nae Np OCA Pale Common: NAMES “Or INSECUS cote a Te I ee ee 2 eS 5 ee DA, RR GCG ent ROL rer tur mie Ae SRM Ac A PST A ale ies Ras er nee DAZ, WunlcuMetal te TODOLUS Se ol beng sein mes Ug y Cie iinet he UA aie 2138 SSO UMEN OTIS sc ei the ONES Reet Rae tay ron eas ASN hi ee eigen ZAGy Report of centennial committee .................. DD st sok Ural ae ot 300 Uae eNOS see ee ag 214 recigentisy (PGIZG eet eg ielea ok ie, a Mite Mecca Se. 215 Dba Gye Wi NG ROSS ate es NE ee ee Cis, we leet ee Ne CY ads 216 STINET SHU SUNS ys eh ge) Klin area ics asta baegegu Ne PS ced s eeleal casa 217 rR URE ee ae Ae ee) ec NUE I Mae iol cays aniad vos se iN ces suahisadnasG cnmoadecanar tte> 223 ee A et) “ Page Line 6 ih 22 29 27 47 28 43 33 26 36 47 36 1 6 26 46 46 47 7 49 2 23 27 56 Hf bo wen AS 64 35 72 2. 5 74 15 18 24 75 21 78 23 81 ie 82 4 83 49 84 5T- 86 14 29 87 1B 94 29 43 95 42 97 43 98 29 100 16 43 102 30 39 105 6 106 23 189 20 111 on 112 24 113 11 114 39 1a = 116 49 122 36 124 32 129 6 132 iy 26 47 160 ig 161 30 179 9 182 24 187 6 198 36 43 204 9 211 19 ERRATA Volume 92 Proceedings of the Entomological Society of Ontario Delete line For For For For For For For For For For For ‘For “csee ps)? read ‘“(see py 21) “Charcteristics” read ‘‘Characteristics” “charcteris-” read ‘“‘characteris-” “recenty” read “recently” charcterized” read “characterized” byt read Sehtit “proprties” read “properties” “higher the net” read “higher net” “aparticular” read “a particular” “fron” read “from” “S. exitiosa” read “S. exitiosa” “ellopsoidal” read “ellipsoidal” Insert period after “Hy” For For For For For For For For For For For For For For For For For For For For For For For “Heeex” read “Essex” “‘mulsions” read ‘‘emulsions” “find” read “wind” “Wisconsi” read “Wisconsin” (oreo ECA ClO2a) a. “1950” read “1850” “invariablly” read “invariably” “overposit” read “oviposit” “longistylum” read “longistylatum’”’ “cannabalize” read ‘‘cannibalize” “ventation” read ‘‘venation” “nedisculus” read “pedisulcus” “pedisculus” read “pedisulcus” “‘almoss” read ‘almost’ “retorse”’ read “retrorse” “retorse” read “‘retrorse”’ “nedisculus” read ‘“‘pedisulcus”’ “quebescense” read “‘quebecense” “earl” read “early” “galae”’ read ‘“‘galeae” “attentuated” read “attenuated” now mm. read. “3.0. mm: 377 “ynedisculus” read ‘“pedisulcus” Insert a period after “Prosimulium” For “at” read “as” For ‘attentuated” read ‘“attenuated”’ For “5.5 mm.,” read: “5.5-mm.;” For “‘“pedisculus” read “pedisulcus” For “males” read “male” Delete ‘‘is’’ For “greyish” read “grayish” For ‘Colection” read ‘‘Collection”’ For “grey” read “gray” For “sub-district” read “subdistrict” For “pupae” read “pupa” For “pedisculus” read “pedisulcus” For “infilling. Terminal” read “infilling; terminal” For “generation” read “generations” Insert period after ‘‘animals” For “euryadminimulum” read “euryadminiculum” For “sprucs” read “spruce” For “linyphids” read “linyphiids” For “Ontario, Canad.” read “Ontario, Canada.” For “Gray” read “Grey” For “perdation” read “predation” Bor. striut’’s read “fruit” For “valume” read “volume” For ‘“overposit” read “‘oviposit” For “aplied” read ‘‘applied”’ For “vicinty” read “vicinity” For ‘one dollar for regular membership” read one “dollar for membership” associate Ae tx Same eS + a Oe oe | ko Levine t 1. SYMPOSIUM UNCONVENTIONAL APPROACHES TO INSECT CONTROL PROGRESS ON THE USE OF INDUCED SEXUAL STERILITY FOR THE CONTROL OF THE CODLING MOTH, CARPOCAPSA POMONELLA (L,) (LEPIDOPTERA: OLETHREUTIDAE)’ M. D. PROVERBS Research Station, Research Branch, Canada Department of Agriculture ; Summerland, B.C. The codling moth, Carpocapsa pomonella (L.), is found in almost all apple-growing areas in the world, and frequently it is the most destruc- tive pest in the orchard. In most areas, the only satisfactory method of control is by chemical sprays. Unfortunately, the constant application of chemicals has created many problems. The use of DDT and Sevin against the codling moth causes, in some manner not fully understood, a pheno- menal build-up of certain species of phytophagous mites. Also, these per- sistent organic insecticides are very destructive to most insects that are parasitic or predacious on aphids, scale insects, and other potentially dangerous insects. Furthermore, the introduction of beneficial insects from other countries is seriously handicapped because of the large amounts of codling moth insecticides that are present on apple trees throughout the growing season. Insecticide resistance is another formidable problem in the chemical control of the codling moth; the insect first became resis- tant to lead arsenate, has more recently developed resistance to DDT, and probably will become resistant to Sevin. Also, the use of persistent chemi- cals may result in soil poisoning. Another important consideration is that of meeting residue tolerances at harvest. It is very evident that some method of controlling the codling moth, other than by the use of chemicals, would be of great value. Control, or possibly localized eradication, by the release of sexually sterile male moths could be the answer. Work was initiated in 1956 at Summerland, British Columbia, to examine the feasibility of using the sterile male technique against the codling moth. This paper outlines the principal results of the investigations up to 1961. Mating With the sterile male technique it is advantageous to know whether or not the female of the species mates more than once. If the female only 1Contribution No. 99, Research Station, Canada Agriculture, Summerland, B.C.; presented as part of a symposium on unconventional approaches to insect control to the 98th annual meeting of the Entomological Society of Ontario, Hamilton, Ontario, November 16 and 17, 1961. Proc. Entomol. Soc. Ont. 92 (1961) 1962 mates once it might be quite satisfactory to release males in which the sperms are inactive or completely dead (von Borstel, 1960). However, if the female mates more than once, every effort should be made to release males in which dominant lethal mutations have been induced in the sperms without affecting the activity of the sperms, for these sperms will have to compete with sperms from normal males. | Experiments showed that, unlike some other species of moths (Wig- glesworth, 1939), the male codling moth deposits one spermatophore only during each copulation. The number of spermatophores found in the bursa copulatrix of the female moth was consequently used as a means of deter- mates once, it might be quite satisfactory to release males in which the mining how many times the female had mated. Dissections of female cod- ling moths collected in British Columbia orchards showed that the female may mate more than once; the average is evidently about twice. Labora- tory work showed that the male moth may also mate more than once. Influence of Heat on Fertility It is well known that reproduction is suppressed when the codling moth is reared at high temperatures (Isely, 1938, 1939; Isely and Schwardt, 1936; Lekic, 1950). Consequently, there was the possibility that sterility— used in the broad sense—could be induced by subjecting the insect to ab- normally high temperatures. Mature larvae, pupae at four stages of de- velopment, and adults were exposed to various high temperatures for dif- ferent lengths of time. Some of the heat treatments induced complete or almost complete sterility, but they also caused prohibitively high larval or pupal mortality, or they reduced the frequency of mating (Proverbs and Newton, 1962). | Influence of Gamma Radiation on Development and Fertility Development The female codling moth was more easily killed by gamma radiation than the male. Furthermore, the difference in suscevtibility between the sexes varied according to the stage of the insect radiated. For example, when 3-to 4-day-old pupae (pupae complete their development in 10-11 days at 80°F.) were exposed to 7,500 rads, 35 per cent of the male and 43 per cent of the female pupae were killed; whereas when mature larvae were exposed to 13,950 rads, 45 per cent of the male and 87 per cent of the female insects died before they reached the moth stage. There was indirect evidence that the female embryo was more easily killed by gamma radiation than the male embryo. For example, when 3- to 4-day-old eggs (eggs complete their development in 6-7 days at 80°F.) were subjected to 9,300 rads and the resulting larvae were reared to adult moths, the sex ratio of the moths, instead of being a normal 1:1, was now 16:1 in favor of the male. It may be concluded that the difference in susceptibility between the sexes was most pronounced when eggs were irradiated, appreciably less pronounced when mature larvae were irradiated, and possibly only just measurable when pupae were irradiated. Work was not done with a suf- ficiently high dosage of radiation to determine if there was any sexual difference in susceptibility when the adult moth itself was irradiated. Generally speaking, susceptibility to radiation injury decreased as development proceeded from the egg to the adult moth. For example, when eggs, less than one day old, were exposed to 9,300 rads, none of the eggs hatched, whereas when mature male larvae were exposed to 13,950 rads, 45 per cent of the insects died before adult moth emergence. When 8- to 6 9-day-old male pupae were subjected to a much higher dosage (46,900 rads) only 14 per cent of the pupae were killed. No immediate mortality was observed when 1-day-old male moths were subjected to 50,000 rads, and the average longevity of the irradiated moths was similar to that of non- irradiated adults. Within at least some stages of the insect, susceptibility to radiation injury decreased with advancement of development. Young pupae were more radiosensitive than old pupae. For example, when 2- to 3-day-old male pupae were exposed to 6,975 rads, 45 per cent of the pupae were killed; whereas when 9- to 10-day-old male pupae were exposed to a much higher dosage (50,000 rads) the pupal mortality was similar to that of non-irradiated pupae. The same relationship held true for the egg; early in embryonic develoment the insect was killed much more easily than in late embryonic development. For example, when eggs that were less than one day old were exposed to 5,000 rads, only 5 per cent of the eggs hatched, whereas when 3- to 4-day-old eggs were subjected to the same dosage, the egg hatch was similar to that of non-irradiated eggs. Fertility 3 At any one dosage of gamma radiation, the degree of sterility in- duced in the female was greater than that induced in the male. This was true whether the insect was irradiated as an egg, mature larva, pupa, or adult moth. For example, when the insects were exposed to the following doses of radiation and the resulting adults were mated with non-irradiated adults (hereinafter called normal adults), the perceitages of eggs that hatched were as follows: Stage irradiated Dosage, vads Type of Mating ee O Adult, 1 day old 40,000 LP SxN’9 3 N¢xI? 0 Pupa, 8-9 days old 10,230 I¢xN? 52 N¢xI? 0 Larva, mature 4,650 I¢xN? 57 : | N7xI¢ 18 Egg, 3-4 days old 4,650 IGxNQ 20 | NoxI9 13 Control 0 Ng¢xN? 76 2T—irradiated insects; N—normal insects. The difference in degree of sterilization between the sexes was evi- dently, then, greatest for pupae, considerably less for larvae, and possibly only just measurable for eggs. Where adult moths were irradiated, the percentage of eggs that hatched was too low to permit an accurate evalu- ation of sexual differences in radiosensitivity. Experiments to determine which stage of the insect should be ir- radiated in order to induce sterility without undesirable side effects showed that the egg stage was not satisfactory; dosages that were high enough to cause sterility or near sterility resulted in prohibitively high mortality during post embryonic development. For example, almost com- 7 plete sterility was induced in the male moth after subjecting eggs during ~ ak late embryonic development to 9,300 rads, but 69 per cent of the larvae died before reaching the mature larval stage, and only 54 per cent of the ‘mature larvae developed into adult moths. Furthermore, when the male moths were caged with normal females, only 18 per cent of the females mated as compared with 85 per cent of the females in control cages. When mature larvae were irradiated, dosages that were sufficiently high to cause complete, or almost complete sterility, adversely affected the mating behaviour and general activity of the adult moths that even- tually developed from these larvae. For example, when mature male larvae were subjected to 9,300 rads, and the resulting moths were caged with normal females, only 2 per cent of the eggs hatched. However, at this dosage the male moths mated approximately one-half as frequently as normal males in the control. Furthermore, approximately 15 per cent of the moths that developed from the irradiated larvae appeared subnormal in activity. When young male pupae were irradiated, dosages that were high enough to induce an appreciable degree of sterility also caused prohibit- ively high pupal mortality. However, when “mature” male pupae (pupae from which the adults would emerge within 24 hours) were irradiated, a high degree of sterility was achieved without causing noticeable pupal mortality or other undesirable effects. When mature male pupae were subjected to 40,000 rads, adult emergence and longevity were not af- fected. The irradiated insects mated satisfactorily with normal females, and, what is most important, only 2 per cent of the eggs hatched. When the dosage was increased to 50,000 rads, 0.5 per cent of tne eggs hatched, but the irradiated males only mated one-half as often as normal male moths in the control. When the dosage was further increased to 65,000 rads, none of the eggs hatched, but this high dosage of radiation killed two-thirds of the pupae, and the moths that did emerge only mated one- third as often as normal male moths. When 1-day-old male moths were irradiated, the degree of sterility induced at any one dosage of radiation was approximately the same as if the insects had been irradiated as mature pupae. A dosage of 50,000 rads or higher affected the mating behaviour of irradiated male adults. Development and Fertility of Offspring of Irradiated Males x Normal Females When moths from irradiated male pupae were mated with normal females, the eggs that were laid did not die immediately, The embryo frequently continued developing for several days, and, as a rule, died at what is known as the “‘red ring” stage. Many of the larvae that did emerge appeared weak and inactive. Consequently, the question that arose was: will the offspring of irradiated males x normal females develop normally? This question was investigated by exposing mature male pupae to 40,000 rads, and mating the emerged adults with normal female moths. Approximately 200 first instar larvae were obtained from these matings. Each larva was placed on an apple to preclude the possibility of cannibal- ism during rearing. Despite this, 92 per cent of the larvae died before reaching maturity. The adults that developed from the surviving larvae were all males. The question that now arose was: are these moths sterile? — There were two few moths to investigate this question adequately, so the dosage was reduced from 40,000 to 30,000 rads in order to get a larger number of offspring to work with. At the reduced dosage 92 per cent (average of two experiments) of the F,; adults were males. When the F, male adults were caged with normal female moths, the moths mated satis- 8 factorily but less than one per cent of the eggs hatched. When the F, fe- male adults were caged with normal male moths, the female moths were receptive to their mates, but they laid relatively few eggs and none of the eggs hatched. From the practical point of view this experiment had special signifi- cance. Perhaps control could be achieved more rapidly if the insects to be released were irradiated, not with a high dosage of 40,000 rads which - would give almost complete sterility, but with a reduced dosage of 30,000 rads. For with the lower dosage the F: offspring that survived would be _ very largely composed of sterile males. It would be a method of obtaining what might be called a “ready made” supply of sterile male moths to help in the control program. Competition of Sperms from Irradiated and Normal Males Since the female codling moth may mate more than once, the next step was to determine whether sperms from irradiated male moths could compete with sperms from normal males. Normal virgin females were mated (a) first with an irradiated male moth (exposed as a mature pupa to 40,000 rads) and then with a normal male, or (b) first with a normal male moth and then with an irradiated male. Most of the eggs that were laid were viable, both in (a) and in (b). Despite the fact that sperms from irradiated moths were not fer- tilizing as many eggs as sperms from normal males, there is one repro- ductive characteristic of the codling moth that might outweigh this dis- advantage of inefficient sperm competition so that control might still be achieved by the sterility technique. Shortly after a female codling moth mates it commences egg-laying; and, if the temperature is favorable, most of the eggs are deposited within 5 or 6 days following copulation (Isely, 1939). Consequently, if sterile males are liberated in sufficiently large numbers to dominate the natural male population, the chances are that the first male a female encounters will be sterile. Following mating, the female will start ovipositing sterile eggs, and may have deposited much if not most of her complement of eggs before she has had a chance to mate with a fertile male. To test this hypothesis, mature male pupae were subjected to 40,000 rads, and the resulting adults caged with normal male and female moths at the ratio of 10 irradiated males to 1 normal male to 1 normal female moth. Larval production was reduced to approximately 20 per cent of that in control cages in which irradiated males were omitted. Thus the hypo- thesis evidently held true, at least for the laboratory. It was decided to carry the experiment a little further. The F, larvae were reared to the moth stage. The sex ratio of these F; moths was ap- proximately 1:1, a ratio that is normally found in laboratory-reared codling moths. On mating these moths with normal ones, it was found that they were about as fertile as normal moths. This was rather disap- pointing, for although it was known that the sperms from irradiated moths were not competing too efficiently, it had been hoped that definite signs of sterility would have been observed in a few of the F, adults. Evidently all the F; moths examined had been derived from the union of eggs with sperms from normal male moths. The question that now arose was: would similar results be obtained if the insects were subjected to 30,000 instead of 40,000 rads? As was mentioned previously, when males that had been irradiated as pupae with 30,000 rads were mated with normal females, the offspring were very at predominantly male, and these males were almost completely sterile. If normal males were introduced into cages containing 30,000 rad males and normal females, would it be found as was found with 40,000 rad males, that the offspring were now fertile? This is exactly what was observed. Neither the F; males nor females showed any appreciable sign of reduced fertility. Possibly, if the experiment had been conducted with a larger number of F,; moths, an occasional sterile individual might have been found. However, from a practical standpoint, we were forced to admit that our original idea of getting sterile F; male moths to help in the control program was not a feasible approach to the problem. Addition of Irradiated Moths to Populations of Normal Moths When the project advances to the stage where sterile moths are being liberated, considerable time and expense would be saved if both male and female moths were released. Consequently, the following experiments were conducted primarily to determine whether such a procedure might influence the rapidity of control or eradication. In a laboratory experiment in which (a) 50 irradiated males or (b) 50 irradiated males and 50 irradiated females (both sexes exposed as mature pupae to 30,000 rads), were added to cages containing 5 normal male and 5 normal female moths, the deposition of viable eggs was re- duced 98 per cent in (a), and 66 per cent in (b). There was considerable variation in numbers of viable eggs from cage to cage within each treat- ment. Neverthless, the results do suggest that the release of sterile fe- males should be avoided. As was shown in the above experiment. an appreciable reduction in biotic potential was achieved when irradiated male moths were caged with normal males and females in the proportion of 10:1:1. To determine whether similar results were likely to occur in the field, a somewhat simi- lar experiment was conducted in cages erected over dwarf apple trees growing in an orchard. Mature pupae were subjected to 40,000 rads, and the emerged adults were caged with normal moths in the following pro- portion: (a) 10 irradiated males plus 1 normal male plus 1 normal female, and (b) 10 irradiated males plus 10 irradiated females plus 1 normal male plus 1 normal female. The number of F, offspring that reached the moth stage in (b) remained about the same as the number of normal moths present in the parent generation; however in (a) the number of F, moths was reduced to about one-third of the number of normal moths in the parent generation. This experiment was repeated and expanded during 1961. The most recent results still must be tabulated and analyzed. However, the data, particularly where the ratio of irradiated to normal males was increased to 20:1, appear so promising that we plan to test the sterility technique in an isolated apple orchard in 1962. Summary Heat treatments induced sterility or near-sterility but caused con- siderable mortality. Gamma irradiation was more successful. Exposure of mature male pupae or newly emerged male moths to 40,000 rads in- duced about 98 per cent sterility without affecting adult emergence, mat- ing, or adult longevity. Higher dosages decreased mating. Irradiation of eggs, mature larvae, or young pupae also resulted in a high degree of sterility, but caused undesirable effects. The female was more radio- sensitive than the male. Sensitivity generally decreased as development 10 progressed from the egg to the adult stage. Mating of a normal female with an irradiated male (40,000 rads), either before or after a mating with a normal male, did not prevent the laying of mostly viable eggs. When irradiated males (mature pupae exposed to 30,000 rads) were caged with an equal number of normal females, the adult offspring were mostly sterile males. However, when irradiated males were caged with normal males and females, in the proportion of 10:1:1, the sex ratio of the offspring was 1 : 1 and both sexes were mostly fertile. In laboratory experiments in which (a) irradiated males, or (b) irradiated males and females were added to cages containing normal male and female moths, in the proportion of ten irradiated moths of each sex to one normal male and one normal female, the deposition of viable eggs was reduced 98 per cent in (a) and 66 per cent in (b). In an orchard experiment (cages over dwarf trees) in which irradiated males (mature pupae exposed to 40,000 rads) were caged with normal males and females, in the proportion of 10:1:1, the number of moths in the F, generation was reduced to about one-third of the number of normal moths in the parent generation. Literature Cited IsELy, D. (1938). Codling moth oviposition and temperature. J. econ. Ent. 31: 356-359. IsELy, D. (1939). Timing seasonal occurrence and abundance of the codling moth. Bull. Arkansas Univ. Agr. Exp. Sta. 382. _ Isety, D. and ScHwaroptT, H. H. (1936). Variations in codling moth injury in northwest- ern Arkansas. J. econ. Ent. 29: 473-476. LEKIc, M. B. (1950). The biology of the codling moth on the Territory of the Serbian People’s Republic and measure for its control. In Serbian, English summary; Plant Prot. 1: 32-65. (Rep. appl. Ent. A, 41: 104. 1953). PROVERBS, M. D. and NEwTon, J. R. (1962). Effect of heat on the fertility of the cod- ling poy Carpocapsa pomonella (L.) (Lepidoptera : Olethreutidae). Canad. Ent. 94: 225-2388. VON BoRSTEL, R. C. (1960). Population control by release of irradiated males. Science 131: 878, 880-882. WIGGLESWorRTH, V. B. (1939). The principles of insect physiology. E. P. Dutton and Co. Inc., New York. (Accepted for publication: February 8, 1962) O NEMATODES AS AGENTS FOR INSECT CONTROL’ H. E. WELCH Entomology Research Institute for Biological Control, Research Branch, Canada Department of Agriculture, Belleville, Ontario Insect parasitic nematodes were known before the turn of this century, but their potential for the control of pests were realized only in the last decade. This developed not only from the renewed interest in biological means of pest control; but also from successful control tests with nematodes in North America, and from the greater knowledge of their taxonomy and bionomics. Ecological knowledge and field experience gained in the utilization of nematodes will be summarized and comments made on the present and future development of the field. A review of the taxonomy, bionomics, and host relations of insect parasitic nematodes is presented elsewhere (Welch, 1962). IPresented as part of a symposium on unconventional approaches to insect control at the 98th annual meeting of the Entomological Society of Ontario, Hamilton, Ontario, November 16 and 17, 1961. Proc. Entomol. Soc. Ont. 92 (1961) 1962 BI Range and Nature of Nematode Parasitism Fourteen families of nematodes are known to be associates of 16 insect orders. This should not be surprising in view of the abundance and variety of the species of the two phyla and the successful exploitation of the parasitic habit by nematodes. The records in Table I are from only a partial review of world literature, but summarize at least 3,300 indi- vidual nematode-insect occurrences and show the main trends. Records of insects as vectors of nematodes of medical and veterinary importance are not included in this table; if they were, then the Mallophaga, Anoplura, and Siphonaptera would also be included. The preponderance of records for the larger orders probably reflects the greater study that these insects have received, as many are pests. Yet each of these orders has insects of many habits and habitats, and where these are favourable to nematodes, then association can be expected. In the Mallophaga, Anoplura, and Siphonaptera, whose specialized species occur in one kind of habitat, the absence of primary parasitic nematodes is not surprising, especially when that habitat is unsuitable for nematodes. The few nematodes for the Heteroptera probably result from the greater attention that is given to the plant species as compared to the soil and aquatic species. TABLE I. Nematode Associations by Insect Orders 3 3 S S R a x a Bs es gt ee ae s § 3 ° 3) ns = om ~ RY = > ‘4 2 > 2.3 9B SB 8 Ose 8. SS SB Be ee E a 3 a S = S 2, = 5 ° ° ms Qa 7 3 Oa SB eee ee Lae in ee SS eer = » = = o 68 =| > oo = simeace ee s E Oy ho eae! Sc OF Re) ea eR ee Sc ae aes ro eee c| O (OQ) S2-80 -8 B 8 4 ae Ae Bea oes Rhabditoidea Rhabditidae ica eee Ae x x x x Se x Diplogasteridae x x x x x Cephalobidae x Xo 7a Neoaplectanidae Xx. EX See Oxyuroidea Oxyuridae Thelastomatidae x Xi See Tylenchoidea Tylenchidae x x Nee Neotylenchidae x Allantonematidae x Mes ae peas Aphelenchoidea Aphelenchoididae x x Aphelenchidae — Sphaerulariidae K 7 ay x Mermithoidea Mermithidae >, fe Te. erage enti nels et? Ck Xo XxX SS eee Tetradonematidae x" 2x No nematode associates of the Protura, "Thysanura, Plecoptera, Mallophaga, Anoplura, Corrodentia, Mecoptera, and Siphonaptera are known. 12 There is a greater frequency of nematode occurrence in those insect orders that are associated with the soil, This tendency is difficult to demonstrate because of the diversity of insect habits. Table II is an ‘attempt to illustrate the tendency for the Coleoptera by assigning the families to arbitrarily designated habitats. The tendency of the nematodes to occur more frequently in insects associated with the soil is apparent in a comparison of the number of nematodes for the ‘Soil’ and ‘Vegetation’ divisions. Actually this table is arranged so that the habitats are in descending order of moisture content and illustrates the great importance of moisture in nematode distribution. Nematodes are aquatic animals, which accounts for their presence in soils as most soils contain moisture. ‘Wood’ habitats are tunnels or galleries produced by the insects and usually also are moist. : TABLE 2. Nematode Distribution Among Families of Coleoptera Predominant Family and number of records Total habitat habitat | of parasitism records Aquatic Dryopidae (3), Dytiscidae (23) Hydrophilidae (31) 57 Moist soil Helmidae (2), Heteroceridae (2) 4 Soil Carabidae (65), Scarabaeidae (282) Silphidae (16), Staphylinidae (37) 400 Dead vegetation Colydiidae (1), Cryptophagidae (3) and fungi Histeridae (3), Lucanidae (20) Mycetophagidae (1), Passalidae (48) Pyrochroidae (1), Rhizophagidae (3) 80 Wood Buprestidae (3), Cerambycidae (40) Scolytidae (434) AT Vegetation Cetoniidae (2), Chrysomelidae (44) Coceinellidae (4), Curculionidae (52) Elateridae (8), Galerucidae (6) Meloidae (2), Trixagidae (1) 114 Dry soil 5 Byrrhidae (1), Nosodendridae (1) 2 Dry media Anobiidae (3), Ptinidae (1) Tenebrionidae (3) re These records inadvertently contain duplicates, particularly in the Scarabaeidae and Scolytidae, where name changes of host and nematode are difficult to trace. Associations of nematodes with insects range from accidental to fatal parasitism. Infected insects may be unharmed, injured, or killed. Most Rhabditoidea are commensals of insects, often utilizing them merely for transportation. The Neoaplectanidae are a notable exception in that its members appear to have an associated bacterium which is pathogenic to insects. The bacteria kill the insect and the nematodes feed on the cadaver following the saprophytic habit of most species of the superfamily. The Oxyuroidea pass most of their life cycle in the insect gut where they feed and breed in the gut contents. Usually their effect on the host is benign but occasionally gut blockage kills the host. Members of the Tylenchoidea and Aphelenchoidea use stylets to pierce the cuticle and enter the host body cavity. These parasites have complex life cycles. Host injury or reduced reproductive capacity results when they emerge via the digestive or genital tract. The Mermithoidea are parasites that because of their 13 large size, 0.5-20 cms. in length, invariably kill their hosts when emerging. Neoaplectanids, tylenchoids, aphelenchoids and mermithids are the groups of most interest to those concerned with insect control. Nematodes in the Natural Regulation of Insects An important question for entomologists is the role and importance of nematodes in regulating natural populations of insects. Most data on nematodes are observational, as few attempts have been made at experi- mental manipulation. , | The literature contains many statements of the percentage parasitism of insects by nematodes. Caution must be exercised in the use of these indices aS measures of interaction. Percentages range from 0 to 100 with most between 10 and 40. Similar rates are given for insect parasites, though few studies permit direct comparisons. Smith (1958) gave percentages for mermithids which were only slightly less than those for dipterous and hymenopterous parasites of grasshoppers. Jourdheuil (1960) investigated flea beetles of crucifers and found similar percentages for allantonematid and hymenopterous parasites, but concluded that the latter were more effective because of their more even distribution and regular occurrence. In habitats unsuited to insect parasites, such as bark _ beetle galleries and black fly streams, nematodes are the dominant form of parasitic regulation. : Rates of percentage parasitism in the literature are usually correlated with environmental characteristics such as temperature and moisture or with the season to show parasite accumulation. Rihm (1954) showed that per cent parasitism ranged from 1 to 32 for bark beetles parasitized by nematodes and was correlated with gallery moisture, and this in turn was correlated with location in the tree. Few workers attempted correlations of percentage parasitism with host abundance. Welch (1959) found that the percentage parasitism of the fruit fly, Drosophila subobscura Coll., by the allantonematid, Parasit- ylenchus diplogenus Welch, 1959, was correlated with fruit fly abundance as measured by weekly trappings over an 18-month period. Rihm (1956) did not find any correlation between percentage parasitism and_ host density, but his investigations were at irregular intervals and with un- related populations. Multiple parasitism is a common feature of nematode parasitism. Frequency distributions of the number of parasites were presented and analysed for allantonematids by Welch (1959), and Jourdheuil (1960), and for mermithids by Sugiyama (1956), Welch (1960) and Wilker (1961). Departures from a Poisson distribution were found which suggest that exposure or susceptibility to parasitism is uneven within an insect population. | Such discontinuous parasite distributions are apparent not only within, but also between populations of the same host. Gendre’s observa- tion (1909) of high but localized parasitism of mosquito larvae by mermithids was duplicated at Churchill where I found neighbouring pools to have infected and non-infected populations of larvae (Welch, 1960). Smith’s observations (1958) confirm this for the terrestrial mermithids of grasshoppers. Rithm (1956) and others found discontinuous distribu- tions for tylenchoid nematodes. | Saunders and Norris (1961) recently illustrated the host density dependence of nematodes. They limited the amount of brood wood for caged populations of the bark beetle Scolytus multistriatus (Marsham), and observed an increase in the percentage parasitism by Parasitaphelen- 14 chus oldhami Rithm, 1956. The authors suggested that this may explain why nematode parasitism reaches high levels in bark beetle outbreaks. While these approaches suggest the role of nematodes in the regula- tion of insect populations, its actual magnitude, in both general and specific cases, remains unknown. The same conflict arises when one consults the informed opinion of those who worked on particular groups for some time. Wachek (1955) and Rthm (1956), who studied the tylenchoid and aphelenchoid parasites of Coleoptera and Scolytidae, re- spectively, considered these nematodes to be of little importance, whereas Niklas (1960) in his study of Melolontha spp., and Rubtsov (1950) on the simuliids considered nematodes important. Perhaps, truth lies in this conflict of opinions: Wachek and Rthm, nematologists, reached their opinion through their general approach, and Niklas and Rubtsov, entom- ologists, reached theirs through work on particular pest groups. In general nematodes are unimportant, but in particular cases they may be significant regulatory factors. Biological Techniques of Pest Control Four techniques of biological manipulation may be defined for pest control. The first is biological control, sensu stricto: the introduction of parasites or predators from the endemic range of the pest. The second technique involves the regular release of large quantities of macro- or microorganisms in much the same manner as chemical insecticides. The third, environmental manipulation, involves the alteration of the environ- ment in such a way as to increase the level of parasite or predator attack. The ae involves the integration of chemicals and organisms in pest control. Mermithids have the greatest potential as agents of biological control. They are relatively large, and with habits akin to those of insect parasites. Neoaplectanids should be of greatest use as biological insecticides because of their high rate of reproduction. Welch (1960) discussed these two groups and their utilization in the control of biting flies. Allantonematids and aphelenchoids are probably best suited to environmental manipulation ; increased moisture through additional humus or cover would increase their effectiveness. Ritthm (1957) considered both tylenchoid and aphelen- choid nematodes unsuited for biological control because of their complex life cycles. Nematode resistance to chemical insecticides should permit their use in conjunction with these chemicals. Control Attempts With Nematodes Oldham (1933) was the first to formally propose the use of nema- todes for biologial control, though Bodenheimer (1928) and Cobb (1927) described the interactions of nematodes and insects. Sweetman (1936), Steinhaus (1949), Théodoridés (1950), and Welch (1958) analysed cur- rent research and its possible application to control. Applied research was with the Necaplectanidae, and was aimed at biological control and more recently at biological insecticide programmes. Four series of studies have been conducted. Glaser and his associates initiated the first series in United States. It resulted from the discovery by Glaser and Fox (1930) of a nematode, Neoaplectana glaseri Steiner, 1929, parasitic in the Japanese beetle, Popillia japonica Newm. Glaser (1931) succeeded in culturing the nema- tode on artificial media, and later in mass culture (McCoy and Glaser, 1936). Establishment in new localities and a resultant mortality of Japanese beetles was obtained by Glaser and Farrell (1935). Glaser, 15 McCoy, and Girth (1940) described the establishment of the nematode in 72 of 73 locales, and found ideal conditions to be soil temperatures of 60-70° F., soil moisture of 20 per cent, high host density, and turf cover. An extensive programme was organized and nematodes introduced into infested areas at, 3!4-mile intervals throughout New Jersey. At the same time Glaser introduced a bacterial disease known as milky disease that proved more effective than the nematode, and consequently the nematode programme was curtailed. Several authorities stated that the nematode did give evidence of a high potential for control, especially as it survived for long pericds at low host densities. : In 1945 this nematode was sent to New Zealand for trials against soil-inhabiting pasture grubs. Dumbleton (1945) tested the nematode for infection of these grubs and recommended field trials. Hoy (1955) carried out these trials, following in general the techniques of Glaser, but though he recovered infected grass grubs, their abundance was not significantly reduced compared to the controls. Hoy considered that this failure was caused by too low soil moisture, and suggested that further tests should be made in soils of greater moisture. He also sent two consignments of N. glasert to the South Pacific for tests against the Rhinoceros beetle, Oryctes rhinoceros L. As this beetle inhabits decaying vegetable matter that has a high moisture content, the results of these trials will be interesting. Hoy (1954) described Neoaplectana leucaniae Hoy, 1954, from the tussock moth, Crambus simplex Butl., but found that it could not survive in soil as distinct from its natural habitat of the base of grass tussocks, and was therefore unsuited for biological manipulation. | The discovery in codling moth larvae, Carpocapsa pomonella (L.) of another neoaplectanid nematode, named DD136, and its associated bacteria by Dutky and Hough (1955) was the basis of the third and fourth series of trials. Dutky worked out the life history and a rearing technique, and discovered the remarkable properties of this nematode (Anonymous, 1956). Nematodes are consumed by the insect, penetrate the gut wall, and enter the body cavity. A bacterium is released that quickly kills the host. The nematodes feed on the cadaver, multiply, and leave after several generations carrying the bacteria with them. In the free-living state the nematodes do not feed but retain the ‘bacteria in their guts. They also enter a resting stage and can be stored for long intervals at reduced temperatures, The nematode is sturdy; it can be sprayed at pressures as high as 100 psi, and will withstand the toxic action of chemical insecticides. Dutky (1959) infected more than 100 insect species in the laboratory, and tested the nematode as a biological insecticide with success against many pests in the field. Chamberlin and Dutky (1958) for example, showed that at high humidities the nematode reduced larval numbers of the tobacco budworm, Heliothis virescens (F.) in the field by 80-85 per cent. Dutky obtained mortalities of 60 per cent or more of codling moth larvae in.treatments of the trunks and main branches of apple trees. Nematodes applied against one brood remained effective against the second that appeared three months later. ) In addition to these studies, Dutky sent material to entomologists for tests in Germany, Netherlands (see appendix of Rithm, 1957), Egypt, Japan, and Chile. Tang (1958) reported successful trials in Peru against crop and vegetable pests. | The fourth series of trials have been made at Belleville. Our objective was to test the nematode as both a biological control agent and a biological Insecticide, and to define the factors that determine its success or failure. Specific pests on various types of plants were therefore selected to give as wide a range of experience as possible. | 16 In field tests cabbages and rutabagas were treated with the nematode for the control of the cabbage root maggot, Hylemya brassicae (Bouché). Root damage was intermediate to that of the checks and chemically treated plants over a range of maggot densities. Nematodes can be used as a biological insecticide by inoculation into the soil or by addition at the time of cabbage transplanting. Their use as a biological control agent will depend on their survival in the soil and agricultural practice. Tests still in progress revealed that nematodes survived at least a year in light sandy soil. Where rotation planting occurs, reinoculation will be necessary. Soil insects obviously offer the greatest possibility for the use of nema- todes as a biological control agent. Another possibility for the use of the nematode as a biological control agent exists in mosquito pools, Laboratory tests revealed that the yellow fever mosquito, Aedes aegypti (L.), and local woodland species of Aedes could be infected at a reasonable dosage for field use. Field trials were conducted and larval populations and adult emergence reduced. To date the nematodes have not been established but have operated only as an insecticide. Where no possibility exists for the transition of the nematodes from the insect population of one year to that of the next, then the nematode can only be used as an insecticide. This was the approach to the nematode trials against the Colorado potato beetle, Leptinotarsa decemlineata (Say), the imported cabbage worm, Pieris rapae (L.), and the corn borer, Ostrinia nubilalis (Hbn.). The dry microclimate of potato plants quickly desiccated the nematodes when they were applied in droplets. Times, dosages, and methods of application were tested to determine if nematode survival could be increased, but to no avail (Welch and Briand, 1961la). Cabbages with more compact foliage should retain more moisture, thus permitting nema- tode survival. The nematode gave caterpillar mortality comparable to chemical insecticides when the cabbages were in head, but no mortality of the caterpillars when the cabbages had only a few leaves (Welch and Briand, 1961b). Chemical insecticide treatment early in the season fol- lowed by late season nematode application might overcome this problem. Corn has a tightly leafed stock that protects the nematode. In trials in 1960 and 1961 the nematode gave protection from corn borer attack equal to that of chemical treatment. Several conclusions may be drawn from these trials. Neoaplectanids can be manipulated as either control agents or insecticides. Their success as the former will depend on survival from one year to another and as the latter on the amount of moisture, and to a lesser degree on host abundance and temperature. _ Future Prospects Recently more research has been directed to the taxonomy, bionomics, and host relations of entomophilic nematcdes, Not only increased know- ledge of insect and nematode symbioses will accrue from continued re- search but also valuable leads for pest control. At the same time those engaged in applied work should search for pest situations suitable to nematodes and for nematodes suitable for pest control. Mermithids have promise as biological control agents, but this needs to be demonstrated in field tests. At Belleville we have undertaken a study the possibility of using mermithids for the biological control of black ies. Nine other known neoaplectanids are available for biclogical control and insecticide tests. Some of these are under study and will probably be found useful. The resistance of neoaplectanids to chemicals is significant Li and needs more study for greater exploitation in the integration of bio- logical and chemical means of control. One is reminded of a statement by Nathan A. Cobb, who in 1927 concluded an article with the remark that “‘control of insects will be most effective if all possible agencies and factors are utilized ; among these agencies nematodes are by no means negligible.” Summary Fourteen families of nematodes are associates of insects of 16 orders. Their distribution is determined by the habitats of the insects; those insects that frequent moist environments are more liable to nematode association. Four nematode groups, the Neoaplectanidae, Tylenchoidea (particularly the Allantonematidae), Aphelenchoidea, and Mermithidae seriously injure or kill their hosts and are of most potential to economic entomology. Nematodes generally play an insignificant role in the natural regulation of insects, but with certain groups of insects their regulation is significant. They may be manipulated as both biclogica!l control agents and biological insecticides, and by altering the environment so as to increase parasitism, or may be used in conjunction with chemical pesti- cides. From trials to date it is obvious that the Neoaplectanidae can be manipulated successfully as biological control agents against soil or aquatic insects. Their role as biological insecticides depends on protection from desiccation. Three main factors are essential to their function in either capacity: moisture, moderate temperatures, and high host density though survival at low host densities is possible. 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Notas generales sobre nematodes portadores de bacterias como un método de control biologico. Rev. peru. Ent. agric. 1: 19-22. THEODORIDES, J. (1950). Les nématodes dans la lutte biologique contre les insectes nuisibles. Bull. anal. Cent. nat. Rech. sci. 9: 73-82. WACHEK, F. (1955). Die entoparasitischen Tylenchiden. Parasitol. SchrReihe (3), 119 pp. WELCH, H. E. (1958). A review of recent work on nematodes associated with insects with regard to their utilization as biological control agents. Proc. 10th Intern. Congr. Ent. 4: 863-868. WELCH, H. E. (1959). Taxonomy, life cycle, development, and habits of two new species of Allantonematidae (Nematoda) parasitic in drosophilid flies. Parasitology 49: 83-103. WELCH, H. E. (1960a). Hydromermis churchillensis n.sp. (Nematoda: Mermithidae) a parasite of Aedes communis (DeG.) from Churchill, Manitoba, with observations of its incidence and bionomics. Canad. J. Zool. 38: 465-474. WELCH, H. E. (1960b). Potentialities of nematodes in the biological control of insects of medical importance. Conf. biol. Control Insects med. Importance, Wash. D.C.: WELCH, H. E. and BRIAND, L. J. (1961a). Tests of the nematode DD136 and an associated bacterium for control of the Colorado potato beetle, Leptinotarsa decemlineata (Say). Canad. Ent. 93: 759-763. WELCH, H. E. and BRIAND, L. J. (1961b). Field experiment on the use of a nematode for the control of vegetable crop insects. Proc. ent. Soc. Ont. 91: 197-202. WELCH, H. E. (1962). Nematode infection of insects. Jn Insect Pathology, An Advanced Treatise, ed. by E. A. Steinhaus. Academic Press, Inc., N. Y. In press. WULKER, W. (1961). Untersuchungen tiber die Intersexualitat der Chironomiden eerpe) nach Paramermis-Infektion. Arch. Hydrob. (English summary), Suppl. 25: 127-181. (Accepted for publication: January 26, 1962) 19 THE PHYSIOLOGY OF SOUND RECEPTION IN INSECTS’ PETER BELTON Entomology Research Institute for Biological Control, Research Branch, Canada Department of Agriculture, Belleville, Ontario Any attempt to use sounds in the control of insects will be aided by a precise knowledge of the physiological processes that are involved. The word sound is used here to describe any mechanical vibrations of the external medium and will therefore include vibrations transmitted through both solid and fluid substrates, as well as airborne vibrations that are inaudible to us because of their high frequency (above about 20,000 cycles/sec.). If the response of an insect to a particular sound is stereotyped then it is possible to draw a ‘reflex arc’ that shows the physiological pathway between stimulus and response. An example of such a pathway is shown | in Fig. 1 which represents the response—a positive phonotaxis—of a Receptor potentials Impulses in sensory nerve Computation inCNS Impulses inmotor nerve Change of wing movement Fic. 1. Diagram showing the physiological mechanism of the response of a male mosquito to sound. The sequence of events reads from top to bottom. male mosquito to the flight sound of a female. The series of events that results from the sound reads from top to bottom of the figure: the sound activates biclogical transducers which are probably the distal processes ‘Presented as part of a symposium on unconventional approaches to insect control at the 98th annual meeting of the Entomological Society of Ontario, Hamilton, Ontario, November 16 and 17, 1961. Proc. Entomol. Soc. Ont. 92 (1961) 1962 20 of sense cells in the second antennal segment (Johnston’s organ) ; these convert the mechanical energy of sounds into electrical changes, the re- ceptor potentials, which in turn give rise to electrical impulses in the auditory nerve. The microphonic potentials that can be recorded in the Johnston’s organ of many dipterous insects (Tischner, 1953; Burkhardt, 1960; Wishart et al., 1962) are probably a complex mixture of the receptor potentials of many cells, together with the impulses that they generate in the auditory nerve fibres. Auditory nerve impulses then undergo energy conversions in the central nervous system, where spatial and temporal patterns of nerve impulses are ‘assessed’ and an output is fed to the motor nerves that activate the direct wing muscles so as to steer the insect towards the source of the sound. The physiological events cannct be described in such a simple way in night flying moths that respond to high frequency sounds by changing direction apparently at random (Roeder & Treat, 1961). The activity of other sensory cells or of cells in the central nervous system of the moths probably causes a variable pattern of impulses to be sent to the several direct wing muscles. Electrophysiological investigations of sense organs give objective information about the type of stimulus that can be converted into nerve impulses; they also reveal the pattern of nerve impulses that are produced by the sounds that evoke responses in the insect. In this review some attempt will be made to collate the results of such experiments. Electrical Responses to Sound In some circumstances the conventional methods of extracellular re- cording can demonstrate receptor potentials and nerve impulses at the same time and with different polarities. A clear distinction between the two types of response is important in order to avoid confusing inter- pretations. In general, the regions of ceil membrane that are thought to convert mechanical into electrical changes, do so in a graded fashion, that is, a gradually increasing deformation of the membrane gives rise to a gradual- ly changing potential difference across the cell membrane. These poten- tials have all the characteristics of those recorded from electrically inex- citable membrane (Grundfest, 1961). The other type of response can be recorded from the nerve fibres running to the central nervous system. These consist of all-or-nothing nerve impulese (action potentials), pre- sumably evoked by the graded electrical changes occurring in the receptor membrane, but which can also be elicited by externally applied potentials. Perhaps the most useful distinction between the two types of response is that the latter (electrically excitable) exhibits refractoriness and has a definite threshold, whereas the former (graded, electrically inexcitable) does not. Thus the frequency of sounds that can be coded directly by means of nerve impulses is limited by the refractory period of the nerve membrane and in insects and vertebrates alike, the auditory nerve ceases to ‘follow’ the stimulus exactly at frequencies higher than about 300 cps. The fre- quency response of the receptor membrane is presumably only limited by the time taken for electrically charged particles to cross it. Even so the graded electrical responses would be, and in fact are in the guinea pig cochlea (Tasaki et al., 1952), considerably reduced at frequencies higher than 10,000 cps. The human ear detects sounds an octave higher than this 21 and impulses have been recorded in the auditory nerve of moths in response 3 to sounds of 200,000 cps (Roeder & Treat 1957), so that the sound waves must be rectified before they can produce impulses in the sensory nerve. The insect sense organs that have been shown to respond to sounds can be grouped into four main categories. Hair Sensilla Hair sensilla are probably the simplest hearing organ, often consist- ing of a single, apparently unspecialized, sensory cell] and a few accessory structures. They can be subdivided according to their size and electrical response into long and short hair sensilla. Impulses recorded from the nerve fibres of the former tend to follow the frequency of the stimulus whereas those recorded from the latter bear no relation to the frequency of the stimulus. Graphs showing the sensitivity of representative sense organs to sounds of various frequencies are plotted to the same scale in Fig. 2. The points represent the minimum sound pressure that elicits a response (hereafter called the threshold response) from the sense organ at a par- ticular frequency. The zero of the vertical scale represents a sound pres- sure of 0.0002 dyn/cm?. An increase of 20 decibels (logarithmic units) represents a tenfold increase of the sound pressure. The threshold response of the hair sensilla of several insects is shown in Fig. 2a. Long hair sensilla occur on the cerci of most orthopteroid insects and results were taken from the family Gryllidae. Responses from short hair sensilla were recorded by Pumphrey (1940) in the Acridiidae although Haskell (1956) was the first to identify them physiologically. Pumphrey (1940) has provided good evidence that these receptors respond to displacement of the air rather than changes in its pressure. One would expect the sensitivity of such receptors to be reduced with an increase of frequency (see p. ), provided that they were not resonant at a particular frequency and did not become adapted to low frequency vibrations. Pumphrey calculated the expected reduction—the straight line in Fig. 2a—to fit the experimental points obtained from the long hair sensilla of Gryllus. Similar long hair sensilla of Homoeogryllus japonicus (Haan) and Xenogryllus marmoratus Haan, studied by Katsuki and Suga (1960) did not behave in this way, and further work is needed to resolve the discrepancy. Wolbarsht (1960) has recently used the ingenious method of electrical recording introduced by Hodgson et al. (1955) to study hair sensilla. By placing a tubular glass microelectrode over the tip of a hair, he demonstra- ted receptor potentials and nerve impulses in response to a variety of mechanical stimuli. Owing to the unusual arrangement of the conducting tissues lying between the glass electrode and the neutral probe, the recep- tor potential is opposite in polarity to the nerve impulse. Wolbarsht ex- ploited this to show that deformation of the receptor membrane reduced its electrical resistance. The characteristics of the receptor potentials and the nerve impulses conform respectively with the criteria given earlier for the responses of electrically inexcitable and excitable membranes. From a study of the hairs in various positions on several insects, Wolbarsht recognized two different types: one produced impulses for as long as the hair was displaced, the other, and more common, produced impulses only while the hair was being displaced and not when its displacement was maintained. If it proves to be possible to vibrate the recording electrode without introducing artifacts, this method will provide useful information 22 on the physiological differences between long and short hair sensilla and yield general information on the phys.cal mechanism of sound reception. Subgenual Organs The remaining hearing organs to be dealt with are supplied by more complex sense cells, chordotonal sensilla, whose anatomy was described from light microscope investigations (Eggers, 1924) and electron micro- scope studies (Gray, 1960). The sense cells usually occur in association with three supporting or structural cells; however, as recordings have not yet been made from single cells it is not known whether there are physiological differences between this type of sensillum and that supply- ing hair cells. Chordotonal organs are distributed throughout the body of many insects, where presumably they act as proprioceptors (Pumphrey, 1940). In many orders of insects they are especially elaborate when they occur distal to the femero-tibial joint (Deba.seux, 1935, 1938). It was suggested (Pumphrey, 1940) that the tibial tympanal organs of gryllids and tet- tigoniids have evolved from part of the subgenual organ, and a comparison of the physiology of these two organs may provide evidence of a link between proprioceptive and hearing mechanisms. 2 Sound pressure in decibels relative toO OOO2dyn/cm Frequency in cycles/sec Fic. 2. Threshold frequency response of various insect hearing organs. The dashed line represents the threshold of the human ear. a. Long hair: Gryllus O——-O (Pumphrey), Homeogryllus ®@ @, Xenogryllus © © (Katsuki and Suga). Short hair: Locusta (%) (Pumphrey). 6. Subgenual organs: Periplaneta O O (Autrum and Schneider), Tettigonia © © (Autrum). Tympanal organ: Tettigonia © @ (Autrum). c. Tympanal organs: Locusta © o, Xenogryllus [e] [=], Gampsocleis & (X), Graptopsaltria ® @ (Kat- suki and Suga), Prodenia O O (Roeder and Treat). d. Johnston’s organs: Anopheles subpictus @ @ (Tischner); Aedes aegypti O O (Original). 23 Autrum and Schneider (1948) have published figures showing the threshold response of the subgenual organs of several insects. It is clear from these figures that extremely small vibrations can be translated — into flexion of the femero-tibial joint, which will stimulate the sensilla. The sensitivity of these organs to airborne sounds will depend on the difference in inertia between the substrate and the bedy of the insect. Whichever has the smaller inertia will act as a sounding board. Subgenual organs will also be sensitive to sounds transmitted in the substrate to an extent that depends on the inertia of the body of the insect. The sensitivity of the receptors of airborne sounds is usually expressed in terms of a response to a certain sound pressure, whereas the response of the sub- genual organ has hitherto been plotted against disviacement. In Fig. 2b the threshold response is plotted in terms of pressure. Pres- sure and displacement were related by the equation p—Kod where p= pressure amplitude, K—a constant depending on the density of the medium and the wave velocity in it, » angular frequency (27f) and d—the dis- placement amplitude. The position of the curves along the ordinate was selected to agree with the threshold power input of the organ in Pertplan- eta (5.9 x 10-" watts) given by Autrum (1943). When they are used to receive pressure changes, the subgenual organs are therefore less sensitive at high frequencies and, comparing the subgenual organ with the tympanal organ of Tettigonia cantans (Sauss.) (Fig. 2b) the former is seen to be relatively inefficient as a receptor of the high frequency sounds produced by stridulation in this group. Tympanal Organs Tympanal organs occur in pairs on the body and range from the simplest thoracic type found in noctuid moths, which have two chordo- tonal sensilla, to the most complex abdominal form of the cicadas with about 1500 sense cells. Some examples of their threshold responses are shown in Fig. 2c. The results of investigations on the following insects were plotted: Homoeogryllus japonicus (Gryllidae), Locusta migratioria (L.) (Acridiidae), Gampsocleis buergeri (Haan) (Tettigoniidae) and Graptopsaltria nigrofuscata (Cicadidae). The fifth curve is based on re- sults obtained from several noctuid moths, Prodenia eridania (Cram.) being typical. There are great differences in the morphological connections between sensilla and tympanum in the various tympanal organs. In the Acridiidae and Lepidoptera the distal processes of the sense cells are attached directly to a point near the centre of the tympanum. In the cicadas they are at- tached to the side of the tympanum, while in the tettigoniids and gryllids the sensilla are attached to the tracheal wall that joins the two tympanal membranes. The comparative studies of Katsuki and Suga (1960) indicate that the acridiid tympanal organ is about as sensitive to sound as that of the cicadas and tettigoniids; although, other things being equal, the sensilla in contact with the centre of the tympanum would be displaced far more. Becht (1958) showed that proprioceptive chordotonal sensilla gener- ate nerve impulses when they are stretched. If the transducer mechanism of tympanal sensilla is similar, then for maximum efficiency the sensilla should be arranged at right angles to the tympanum. This is not so, even in the cases where the sensilla are connected to the central region of the tympanum (Roeder & Treat, 1957; Gray, 1960). Experiments using scale models of various hearing organs may answer some of these questions; 24 it seems unlikely that the design of these transducers, which are in some cases more sensitive than man-made devices, could be as inefficient as they appear at first sight. Johnston's Organ Although the experiments of Roth (1948) showed fairly conclusively | that the Johnston’s organs of male mosquitos were the receptors involved in their behaviour to sounds, Tischner (1953) provided the first electro- physiological evidence of this function. He measured the saturation re- sponse characteristics (the electrical response does not increase above this level despite an increase in sound pressure) and from this extrapolated a curve of the threshold response. It can be seen from his figures for Anopheles subpictus Grassi (Fig. 2d) that the sensitivity of this organ is greater than that of the average human ear. Wishart and Belton made direct measurements of the threshold frequency response of male Aedes aegypti (L.); a typical curve is shown in Fig. 2d. The agreement between the two species is remarkably close. As the antennal nerve is extremely short, recordings have so far been made from the conducting tissue of Johnson’s organ itself, with the result that the potentials are probably a mixture of receptor potentials and nerve impulses. However, it is clear that the response of individual sense cells in Johnston’s organ is related to the frequency of the stimulus and is in this respect different from the asynchronous response of the other chordotonal sensilla that have been examined. Another unusual feature of the antennal hearing organ that it is capable of responding to sounds from any direction except directly in front or behind, that is, along the axis of the antenna. Conclusions A study of the physiology of insect hearing organs is only a part of the large programme of research needed before the control of insects by sound becomes practicable. This discussion is intended to emphasize the importance of sound in the insect world, as shown by the wide distribution of sense organs that respond to sounds over a total range of about 13 octaves, many of them completely inaudible to man. As more information on the phonotactic and phonokinetic behavioural responses of insects be- comes available, the imaginative insect controller will be able to use synthetic and recorded sounds to his advantage. Information on the phy- siology of sense organs will be a useful guide to the ethologist in planning his experiments. It has already been possible to attract male mosquitces (Kahn et al., 1945), male and female cicadas (Alexander & Moore, 1958), to influence the behaviour of locust swarms under certain conditions (Haskell, 1957) and to reduce the number of moths attracted by light traps (Treat, 1962, personal communication; Wishart, 1962, unpublished results) by means of natural or recorded sounds, or, as in the last example by synthetic stimuli. Acknowledgments It is a pleasure to acknowledge the helpful discussions I have had with Asher Treat of the Department of Biology, the City College of New York and George Wishart of this Institute. Literature Cited ALEXANDER, R. D. and Moors, T. E. (1958). Studies on the acoustical behaviour of seventeen-year cicadas. Ohio J. Sci. 58(2): 107-127. AUTRUM, H. (1943). Uber kleinste Reize bei Sinnesorganen. Biol. Zbl. 63: 209-236. 25 AUTRUM, H. and SCHNEIDER, W. (1948). Vergleichende Untersuchungen iiber den Erschiitterungssin der Insekten. Z. vergl. Physiol. 31: 77-88. BECHT, G. (1958). Influence of DDT and lindane on chordotonai organs in the cock- roach. Nature, Lond. 181: 777-779. BURKHARDT, D. (1960). Action potentials in the antennae of the blowfly (Calliphora erythrocephala) during mechanical stimulation. J. Ins. Physiol. 4: 138-145. DEBAISEUX, P. (1935). Organes scolopidiaux des pattes d’insectes. La Cellule 44: 273-314. DEBAISEUX, P. (1938). Ibid. 47: 79-202. Eccers, F. (1924). Zur Kenntnis der sntennalen stiftfiihrenden Sinnesorgane der Insekten. Z. Morph Okol. Tiere 2: 259-349. GRAY, E. G. (1960). The fine structure of the insect ear. Phil. trans. Roy. Soe. B Qiss Ep-94- GRUNDFEST, H. (1961). Functional specifications for membranes in excitable cells. In The Regional Chemistry, Physiology and Pharmacology of the Nervous System. Pergamon Press, London. HASKELL, P. T. (1956). Hearing in certain Orthoptera. 1 Physiology of sound re- ceptors. J. exp. Biol. 33: 756-766. HASKELL, P. T. (1957). The influence of flight noise on behaviour in the desert locust, Schistocerca gregaria. J. Ins. Physiol. 1: 52-57. Hopeson, E. 8., LETTVIN, J. Y. and ROEDER, K. D. (1955). Physiology of a primary chemoreceptor unit. Science 122: 417-418. - KAHN, M. C., CELESTIN, W. and OFFENHAUSER, W. (1945). Recording of sounds pro- duced by certain disease-carrying mosquitoes. Science 101: 335-336. KATSUKI, Y. and SuaGa, N. (1960). Neural mechanism of hearing in insects. J. exp. Biol. 37: 279-290. PUMPHREY, R. J. (1940). Hearing in insects. Biol. Rev. 15: 107-132. ROEDER, K. D. and TREAT, A. E. (1957). Ultrasonic reception by the tympanic organ of noctuid moths. J. exp. Zool. 134: 127-157. ROEDER, K. T. and TREAT, A. E. (1961). The detection and evasion =e bats by moths. Amer. Scient. £49: 135- 148. Rory, L. M. (1948). A study of mosquito behaviour. Amer. Midl. Nat. 40: 265-352. TASAKI, L., DAvis, H. and LEGourx, J. P. (1952). Space-time pattern of cochlear mi- crophonies (guinea pig) as recorded by differential electrodes. J. acoust. Soc. Amer. 24: 502-519. TISCHNER, H. (1953). Uber den Gehorsinn von Steckmucken. Acustica Suisse 32: 335-343. ; WISHART, G., van SICKLE, G. R. and RIORDAN, D. F’.. (1962). Orientation of the males of Aedes aegypti (L). to sound. Canad. Ent., in press. Wo.parsut, M. L. (1960). Electrical characteristics of insect mechanorecptors. J. gen. Physiol. 44: 105-122. Accepted for publication January 26, 1962 ——— CONTROL OF INSECTS IN FOODSTUFFS BY HIGH-FREQUENCY. ELECTRIC FIELDS! F. L. WATTERS Research Station, Research Branch, Canada Department of Agriculture, Winnipeg, Manitoba Physical methods are sometimes used in place of insecticides to control insects in stored products. Foodstuffs that become infested may be heated by conduction or convection to the lethal temperatures of the insects. How- iContribution No. 104, Research Station, Research Branch, Canada Department of Agriculture, Win- nipeg, Manitoba; presented as part of a symposium on unconventional approaches to insect control to the 98th annual meeting of the Etomological Society of Ontario, McMster University, Hamilton, Ontario, November 16, 17, 1961. : Proc. Entomol. Soc. Ont. 92 (1961) 1962 26 ever, this is often a slow procedure, heating is non-uniform, and pre- cautions must be taken to prevent heat damage to the product. A more promising approach is to heat the foodstuff indirectly by exposing it in a high-frequency (H.F.) electric field. The electrical energy produced wi- thin the foodstuff degenerates rapidly as heat, Heating may be controlled by regulating the field strength and the frequency. The unique feature of H.F. heating is that electrical energy is imparted uniformly to the commodity. Thus, all parts tend to be heated simultaneously. Since most biological materials are composites we may expect that in an H.F. electric field, each component will have a character- istic heating rate. Furthermore, since insects contain fluids of high elec- trical conductivities, we may expect that the insects will be capable of absorbing more electrical energy in an H.F. electric field than dry food- stuffs that they infest; if this is so, the insects may heat more rapidly. The possibility that insects may be selectively heated within a foodstuff | indicates that economies may be achieved in this field of insect control that have not been fully exploited. This paper deals mainly with selective heating of insects in H.F. electric fields with reference to possible applications in the agricultural and food industries. The first worker to observe the heating of animals exposed in a high-frequency electric field was d’Arsonval (1893). The next published work in this field was by Schereschewsky (1926) who reported that mice were killed more readily between 18 and 66 megacycles per second (mcs) than at other frequencies tested (8.3 to 135 mes). The implication was that maximum heating occurred at a certain frequency. Thomas (1952) in a comprehensive review of the literature stated that the existence of a frequency at which maximum heating might occur is not compatible with electrical theory. He attributed decreased effectiveness at 66 to 135 mes to higher power losses than he thought was likely to occur at the lower frequencies used. Headlee (1931, 1932, 1933, 1936), who pioneered the work with in- sects in this field, suggested that adults of holometabolous insects were more susceptible to heat injury than the larvae. He attributed this to the higher degree of differentiation of the nervous system of adults. He noted that both nymphs and adults of hemimetabolcus insects required approximately the same exposure period in an H.F. electric field to kill them. Headlee speculated that each insect may have its own resonant fre- quency at which it may be killed in an H.F. electric field. However, his later work and that of others have not confirmed this. There is little evidence that factors other than heat are involved in the death of insects in an H.F. electric field. However, Hartzell’s (1934) results with larvae of Tenebrio molitor indicate that H.F, heating causes solution of certain cells in the ganglia whereas these cells in larvae killed by external heating showed no evidence of solution but rather of coagu-. lation. Electrical Charcteristics of Biological Materials Dielectrics have certain characteristic that distinguish them from metallic conductors. First, since they can be “charged’’ or polarized when subjected to a high voltage, they can store electrical energy; charging the condenser so formed, places an electric stress on the dielectric, the extent of which depends on its physical and chemical vroperties. Second, dielec-. trics are characterized by the presence of ions which exhibit translatory 27 motion along the lines of force. Such movement is associated with ionic or electrolytic conduction which produces heat. The rate of heat production in a dielectric is expressed by: dT = KE?FL dt SC where T is temperature in °C. t is time in sec. EK?—average voltage gradient in volts per cm. F—frequency in megacycles L—dielectric loss factor S—density, gm. per cm.? C=specific heat cals per °C per gm. The dielectric loss factor, which is the term cften used to chaveletarine a dielectric represents the product of the permittivity and the loss tangent or dissipation factor. Permittivity represents the amount of electrical energy that can be stored in a dielectric. Water content greatly influences the magnitude of permittivity of solid dielectrics. Since the permittivity of water is 80, biological materials that have a high proportion of water may be expected to have relatively high permittivities. Loss tangent is the other variable used to calculate dielectric loss factor. It represents the fraction of electrical energy transferred to the dielectric that is absorbed as heat (Hartshorn, 1949). Thus, the amount of heating that occurs in a dielectric in an H.F. electric field is a function of permittivity or amount of energy stored x loss tangent or amount of energy absorbed. Measurements of the dielectric characteristics of insects and cereal products carried out at our laboratory showed that the values of dielectric loss factor were higher for insects than cereal products. Typical values for cereal products such as flour, bran and wheat. ranged from 0.25 to 0.60 depending on moisture content and the degree of compaction. The values showed a slight increase as the frequency was increased from 15 to 55 mes. The dielectric loss factor for adults of Tribolium confusum Duv. and Sitophilus granarius (L.) ranged from 2.0 to 2.5. Tribolium larvae, freshly removed from cultures, gave values of 4.0 but these values decreased when the larvae became desiccated. The results indicate that insects are capable of absorbing more elec- trical energy than cereals that they often infest. Thus, there is basis for infering that insects may be selectively heated when they are present in dry cereal products exposed in an H.F. electric field. Selective Heating As has been already mentioned, most biological! materials are com- posites, each part having its individual electrical and thermal charcteris- tics which govern the production of heat within it, However, the individual contributions of particular components may be swamped by the overall averages. For instance, although cholesterol, a characteristic component of nerve tissue, has a high heating rate in an H. F. electric field, this apparent advantage, insofar as causing the death of organisms is concerned, may be nullified by the electrical and thermal characteristics of surrounding tissues, which may tend to suppress the higher heating rate. If the heating rates of certain tissues are modified by adjacent tis- sues then we may expect that the heating rates of insects in the presence of a surrounding medium are similarly changed. Certainly, the most at- 28 tractive feature of controlling pests by the use of H.F. electric fields is the possibility that the pest may be heated at a faster rate than the pro- duct it infests. If this should occur, the pest would reach a high lethal temperature while the product would be heated only to temperatures well below the limits at which it might be damaged. Thus, not only would the insects be killed without risk of thermal damage to the product but, also, much less electrical energy would be needed to kill the insects than if the entire product were heated to the lethal temperature of the insect. This intriguing possibility has interested various workers in this field and several have reported instances of apparent selective heating where insects in products exposed in an H.F. electric field were killed at tempera- tures well below those previously reported as fatal (Hartzell, 1934; Weber et al, 1946). Headlee (1931) reported that frequencies of 2 to 3 mes at a field strength of 4000 volts per inch were more conducive to heating honeybees selectively in an H.F. electric field than frequencies of 12 to 15 mcs at the same field intensity. However, Headlee’s methods of calculating the field intensity are questionable (Thomas, 1952) and it is possible that the more favorable results at the lowest frequencies may be attributed to higher field intensities rather than to selective heating. Hartshorn (1949) in reference to selective heating effects has pointed out that the heat generated in composite dielectrics depends on the orienta- tion of the components in the field. Those components that are parallel with the field will absorb more electrical energy than those that are ver- tical to the field. Frings (1952) and Thomas (1952), also, stress the importance of the orientation of objects in an H.F. electric field for the development of heating effects. In fact, Frings has attributed apparent instances of se- lective heating to the disposition of specimens parallel to the field. Since insects, in a porous medium, are likely to become active as the product — begins to heat, those that orient themselves parallel with the field will heat at a faster rate than those that remain vertical to the field. Frings (1952) referred to the work of Hosmer (1928) in explaining why adult flies are killed more readily than grubs. Hosmer exposed tubes of simple salt solutions in an H.F. electric field at various angles. Those that were parallel to the field boiled instantly and the heat was immedia- tely conveyed to connecting tubes. Frings exposed in an H.F. electric field normal flies and flies with the legs and wings removed, so that they occu- pied 10 per cent of the vertical field. At a field intensity of 1000 volts per em at 25 mes, the normal flies were knocked down in less than 1 second, and extended the proboscis rigidly in 9 seconds. Wingless flies acted simi- larly. But it took legless flies 23 seconds to show symptoms of death. In more recent work, Whitney et al (1961) have reported that many adults of Sitophilus granarius, Tribolium castaneum, T. confusum and Rhyzoper- tha dominica were injured after exposure to an H.F. electric field. The injuries consisted of appendages that were broken at the femur or tibia. If Frings’ hypothesis of the action of H.F. electric fields on insects is correct, then injuries of this nature may be expected. Thomas (1952) has developed formulae that give the limits for se- lective heating of insects in a medium exposed to an H.F. electric field. Basing his predictions on fundamental principles of electromagnetic theory he has derived equations for determining a differential heating factor which can be used to estimate the relative heating rate of one component (insects) imbedded in another. His basic assumption was that the insect 29 may be considered as a spherical object imbedded in an infinite medium. If both the insect and the medium are subjected to an electric field, then the field intensities developed in each component will depend on their electrical properties and the orientation of the insect in the field. Thomas’ caleula- tions have shown that for substances having similar H.F. conductivities, the value of the differential heating factor is not influenced by shape, i.e., according to theory the object may be either spherical or tubular. The applied frequency must be high enough to heat both the object and the medium. In recent work, Whitney et al (1961) have attempted to correlate an extensive series of practical treatments with electromagnetic theory. The frequencies used were 5, 10 and 38.6 mes. Field intensities were ad- justable from 1.2 to 7.3 KV/in. They calculated values for the differential heating factor of insects in either wheat or wheat shorts, from the ratic of the average heating rate of insects to the average heating rate of the product. Close agreement was obtained between the differential heating factor obtained from basic equations and that obtained in practice. How- ever, since the electrical characteristics of all components in the H.F. electric field are temperature-dependent, the differential heating factor, also, is temperature-dependent and was shown to decrease in value as the grain temperature increased. Thus, it appears that differential heating is more pronounced at temperatures much lower that those usually con- sidered to be the lethal temperatures of the insect. At high temperatures (150° to 170° F.), selective heating effects are not so obvious because the heat generated within the insect is maintained by the high temperature of the medium. Baker et al. (1956) maintained that there was no selective heating of adult Tribolium confusum and Sitophilus granarius exposed in flour in a cavity resonator operating in pulses at a frequency of 2.45 x 10° mes (12.25 cm wavelength). They stated that it was necessary to heat the flour or wheat to the lethal temperatures of the insects to obtain a com- plete kill. However, since temperature measurements were made after exposure of the product to the H.F. electric field, it is likely that the pro- duct actually attained a much higher temperature than that indicated. Also, at conditions where selective heating may be expected, it is possible that heat losses from the resonant cavity resulted in survival of insects near the sides. Van den Bruel et al. (1960) have shown that heat losses from the periphery of bagged flour treated in H.F. electric fields at 40 and 80 mcs may enable a high proportion of insects to survive. H.F. heating for the disinfestation of products other than cereals has also been investigated. Thomas and White (1959) have reported that woodworm beetles (Lyctus brunneus) in oak sapwood were controlled at a frequency of 76 mcs at a field strength of 2400 volts per inch. How- ever, they pointed out that although some selective heating of insects may have occurred, this was not relied on to control the insects. Wood tempera- tures of at least 65° C. were necessary to obtain a complete kill at an ex- posure period of about one minute. The apparent absence of pronounced selective heating effects might have been due to the insects con*acting the _ wood. This would provide for greater heat losses in the insect than would be the case if the insect was in intimate contact with a granular material of low heat conductivity. Lowrey et al. (1954) have used H.F. electric fields to kill the pink bollworm in cotton seeds. There was no evidence that the insects were selectively heated under the experimental conditions used, However, this 30 possibility apparently was not specifically investigated by the authors. No further reference to H.F. treatment of bollworm infestations in cotton seed has been found in the literature. Frings (1952) investigated the use of H.F. electric fields to disinfest fruits and vegetables. He concluded that there was little prospect of selectively heating the insects inside their hosts. Thomas (1952) has noted that theoretical considerations preclude selective heating occurring in products that have electrical characteristics of the same order as the insects themselves. Stored Product Applications Of all the applications for controlling insects by H.F. electric fields, the disinfestation of cereal products probably offers the greatest oppor- tunity for exploitation. However, although practical tests and mathemati- cal theory show that selective heating occurs in some cases, it cannot always be relied upon to kill the insects. This is due partly to the fact that insects may be oriented in different planes to the H.F. electric field and, also, stages that are imbedded in grain kernels absorb !ess electrical energy than those that are between the kernels. Whitney et al. (1961) have shown that selective heating ratios of insects in wheat decreased with an increase in temperature. As the temperature of the wheat increased, selective heat- ing of the insect became less\ pronounced because the wheat temperature then approached the lethal temperature of the insect, When the lethal temperature is reached, it must be maintained long enough to kill the in- sect. Critics of the H.F. method of heating will say that this can be done equally as well and possibly cheaper by conventional heating methods. However, the heating of infested products by H.F. electric fields offers three important advantages over conventional methods: First, high tem- peratures can be induced rapidly and uniformly in the product to be treated. Premature cooling of the outer layers may be prevented by pass- ing the product through a heated oven in order to maintain an adequate time-temperature product to ensure destruction of the pest; second, the method can be adapted to conveyor systems that are already well estab- lished in the grain handling and food processing industry. Thus, the pro- duct can probably be heated as part of normal food handling procedures; third, the insects themselves tend to be heated, initially, at a faster rate than the surrounding cereal. The extent of this action may be modified by the electrical and thermal properties of the surrounding cereal. Thus, heat losses from the insect to the surroundings would tend to be high in media having high thermal conductivities. Probably the most important factor militating against the use of H.F. electric fields for the control of insects in cereal products is the widespread use of safe chemical controls. Insecticides and fumigants are highly ef- fective for preventing as well as for controlling infestations. Thomas (1952) has estimated the cost of H.F. treatment of grain in Great Britain at about 1.5 cents per bushel, This included amortization, maintenance and operating expenses. More recently, Whitney et al. (1961) estimated the cost at 3.5 cents per bushel in the U.S. These costs were calculated on the basis of raising the grain temperature from about 70° F. to 150° F. The costs would, of course, be higher with lower initial grain temperatures. In Canada, fumigation of large grain bulks can be carried out for 1.5 to 2 cents per bushel depending on the fumigant and the equip- ment that is used. Webber et al. (1946) found that H.F. electric fields could be effec- tively used to control insects in specialty packaged products. However, excessive field strengths on the electrodes during certain of the treatments ol resulted in arcing and subsequent burning of the outside covering. It is doubtful whether package treatments would be approved by food inspec- tors since they might be inclined to regard a dead insect in a sterilized food package as objectionable as a live one in an unsterilized food pack- age. The most hopeful application of H.F, electric fields in the food in- dustry is for the treatment of processed foods before they are packaged. Such foods would have to be aspirated and screened to remove the dead insects before the food was packaged. At present, the use of H.F. electric fields to control insect pests ap- pears to be limited. The lethal effect is considered by most workers to be due entirely to the induction of high temperatures within the insects. Although there is evidence that, under certain conditions, insects are heat- ed selectively in an H.F. electric field, the higher heating rates of the in- sect cannot be relied upon solely to achieve complete control. Until new information on the effectiveness of the H.F. method of controlling insects comes to light, it is unlikely that this unconventional approach to the control of insects will become conventional. Literature Cited D’ARSONVAL, A. (1893). Influence de la fréquence sur les effects physiologiques des courants alternatifs. Compt. Rend. Acad. Sci. (Paris) 116 : 630. BAKER, V. H., WIANT, D. E. and TaBoaDA, O. (1956). Some effects of microwaves on certain insects which infest wheat and flour. Jour. econ. Ent. LD” 238 van den BRUEL, W. E., BOLLAERTS, D., PIETERMAAT, F. and van DisicK, W. (1960). Etude des facteurs déterminant les possibilités d’utilisation du chauffage diélec- trique a haute fréquence pour la destruction des insects et des acariens dissimulés en profondeur dans les denrées alimentaires empaquetées. Parasitica 16 : 29. FRINGS, H. (1952). Factors determining the effects of radio- frequency electromagnetic fields on insects and the materials they infest. Jour. econ. Ent. 45 : 396. HARTSHORN, L. (1949). Radio-frequency heating. George Allen & Unwin Ltd., Ruskin House, London. HARTZELL, A. (19384). Histopathology of insect and nerve lesions caused by insecti- cides. Contr. from Boyce Thompson Inst. 6 : 211 HEADLEE, T. J. (19381). The differential between the effect of radio waves on insects and on plants. Jour econ. Ent. 24 : 427 HEADLEE, T. J. (1932). Further studies on the effects of electro-magnetic waves on insects. Jour. econ. Ent. 25 : 276. HEADLEE, T. J. (1933). The effect of radio waves on internal temperatures of certain insects. Jour econ. Ent.-26—-+ 313. HEADLEE, T. J. and JopBINs, M. D. (1936). Further studies of the use of radio waves in insect control. Jour. econ. Ent. 29 : 181. Hosmer, H. R. (1928). Heating effects observed in a high frequency static field. Sci- ence 68 : 825. Lowry, W. L. and CHAPMAN, A. J. (1954). Tests of the dielectric treatment of cotton seed for destroying pink bollworms. Jour econ. Ent. 47 : 1022. SCHERESCHEWSKY, J. W. (1926). The physiological effects of currents of very high frequency (135,000,000 to 8,300,000 cycles per second). Public Health Rpts. (Uni- ted States) 41 : 19389. THomas, A. M. (1952). Pest control by high-frequency le erie fields—Critical Résumé. Technical Report W/T23. British Electrical and Allied Industries Research Association, Leatherhead, Surrey. THoMAS, A. M. and WuitTs, M. G. ey The sterilization of insect-infested wood by high- frequency heating. Wood 24 : 407. WEBBER, H. H., WAGNER, R. P. and PEarRson, A. G. (1946). High-frequency electric fields as lethal agents for insects. Jour. econ. Ent. 39 : 487. WHITNEY, W. K., NELSON, S. O. and WALKDEN, H. H. (1961). Effects of high- frequency electric fields on certain species of stored-grain insects. U.S.D.A. Marketing Research Report No. 455 Accepted for publication January 29, 1962 o2 SOME BIOLOGICAL EFFECTS OF ATMOSPHERIC ELECTRICITY’ M. G. MAW Entomology. Research Institute for Biological Control, Research Branch, Canada Department of Agriculture, Belleville, Ontario The idea that electricity exists in the air was recognized when light- ning and thunder were shown to be large-scale manifestations of effects that can be obtained with static electricity in the laberatory. The earliest reference to this suggestion was by Wall in 1708, who observed crack- lings and a flash when he held charged amber a small distance from his finger, and remarked that “it seems in some degree to represent thunder and lightning’? (Chalmers, 1957). With the growth of aviation and space travel the physics of the at- mosphere has become increasingly important, The possible effects that the various radiation bands might have upon living matter and the possibili- ties of weather control have created new disciplines or at least new aven- ues in the conventional disciplines. Before 1950 investigations of the biological effects of atmospheric electricity were subjective and speculative and in the absence of precise data are questionable. The late W. Wesley Hicks perhaps helped most to revive interest in air electrification and its possible biological effects. His work and sponsorship attracted several men who produced a variety of valuable technical and medical data (Kornblueh and Speicher, 1957). By 1956 more than 50 controlled investigations had been conducted (Hicks, 1956). The immediate goal of this research was to establish beyond ques- tion that air ions can have an effect on biological activities. Until recenty little interest has been shown in the effect of atmos- pheric electricity on insects. Circumstantial evidence shows that variables more subtle than the conventional ones may influence insect activity. For example, caged adult spruce budworm, Choristoneura fumiferana (Clem.) kept in an illuminated, air-conditioned room sometimes rouse from near torpor as a cold front approaches (Wellington, 1957). Haine (1957) re- ported that. activity and moulting rates in aphids increased at certain times even under the constant temperature and light conditions of a cel- lar. The intensified activity could not be correlated with changes in rela- tive humidity, barometric pressure, hours of sunshine or with any hour before or after sunrise or sunset. The weather was, however, charcterized by rapid changes between sunny periods and passing heavy showers. Steiner et al (1961) reported that unusually high trap catches of various insects were often associated with approaching storms: of all the fruit flies caught by them at Miami in a 30-day period, 37.7 per cent were caught two days before the predicted arrival of a particular hur- ricane. At another site 44.6 per cent of the catch was obtained during the same period. They suggested that factors preceding this storm front in- creased catches by stimulating greater flight activity, by increasing the attractivity of the lure, or the sensitivity of the fly. Entomologists have often noted the increased activity of insects prior to storms by Schuia (1952) was the first to experiment with atmos- pheric electricity and insect behaviour. The lack of records on atmospheric pressure fluctuations partly invalidates his studies on the influence of fluctuating electrical fields on honey bees, but he did show that worker 1Presented as part of a symposium on unconventional approaches to insect control at the 98th annual meeting of the Entomological Society of Ontario, Hamilton, Ontario, November 16 and 17, 1961. Proc. Entomol. Soc. Ont. 92 (1961) 1962. bees increased their foraging and food uptake during periods of electri- cal disturbance and guard bees became hostile when electrodes with al- ternating potentials were placed at either side of the hive entrance. Effects of Air Ions Levengood and Shinkle (1960) found that Drosophila melanogaster Meig. yielded more progeny than control groups with rising barometric pressure occurring during the mating period and less with decreasing pressures. When the cultures were subjected to an electrical field the average progeny yield increased by 34.4 per cent over the average for the controls and variations in the yields attributable to pressure were damp- ened (Levengood and Shinkle, 1961). They believed that because ionization levels increase with decreasing pressures, the increased ionization inhibi- ted in some way the yield in the control groups. That is, the electrical field was shielding the insects in some way from the effects of the ions. Perhaps differences in ionization levels might account for some of the conflicting reports in the literature of the effects of pressure under natural vs. artificial changes affected in the laboratory. Edwards (1960b) subjected the blowfly Calliphora, vicina R. D. to different densities of artificially-produced unipolar air ions. With moder- ately high positive-ion density flight activity increased with the peak occurring approximately three-quarters of an hour after the first expos- ure to the ions. Following the peak activity returned to the original level while the insects were still exposed to the ions. This infers a type of adaptation to the ionic content of the air. No effect on activity was noted with similar density of negative ions. Effects of Potential Gradients The ionic content of the air and potential gradients are closely related In nature as an increase in the ionization level leads to greater conductivi- ty of the air and thus the potential gradients become smaller. When Edwards (1960a) subjected D. melanogaster and C. vicina to potential gradients he found that activity in the former was temporarily reduced. The period of reduced activity was prolonged by reversing the field polarity at five minute intervals. In C. vicina a much stronger field than that used with D. melanogaster had to be employed to produce even a transient reduction of activity. Maw (196la, 1961b) showed similar re- ductions in the activity of the hymenopterous parasites Itoplectis conquist- tor (Say) and Scambus buolianae (Htg.). The former moved over a po- tential gradient on a charged surface toward a light until they encountered a particular potential. Here they remained until they became “acclima- tized” or had acquired a charge like that of the surface upon which they rested. Complete cessation of locomotion could only be realized by applying voltages much greater than would be found under natural circumstances. With S. buolianae the effect of a fluctuating field was manifest in re- duced egg production in a given period. Edwards (1961) subjected the pupae of the phantom hemlock looper, Nepytia phantasmasia Stkr., to potential gradients and found that adult emergence was retarded by as much as a day over that of the controls. Adults in the control groups deposited more eggs than did those in the elec- trical fields, with the fewest being deposited in a constant electric field. Maw (1961b), however, found that more eggs were deposited by S. buolia- nae when the adults were subjected to a steady electrical field, and also when they were in an environment which was shielded from ambient fields, as compared to those in normal rearing situations and in fluctua- 34 ting fields. One reason for the differences may be that the field strengths used by Edwards was much greater than those used by Maw. It is felt that the voltages used by Maw were more closely related to normal fair weather and to weak weather systems than to the active storm situation used by Edwards, Maw considered the reduction in oviposition rate to be of a physical nature, that is, the insects were temporarily arrested by a change in potential and did not oviposit until they had adapted to the new environment. A jolt of the cage, a change of light intensity, a blast of air, or a moving object will produce a similar temporary stoppage of activity. Insects in a shielded environment or in a constant field do not have to contend with an ever-fluctuating factor, and so are able to oviposit more eggs undisturbed in a given period. The constant field and the shielded environment were in effect protecting the insects from outside electrical disturbances. This contention tends to support the findings of Levengood and Shinkle (1961). Recent Work at Belleville The more recent work at Belleville concerns the flights of insects in general, and the mosquito, Aedes trichurus Dyar, in particular. Trees and shrubs are surrounded by electrical gradients that result from normal point discharge phenomena and induction processes which are common under favourable conditions of charge and potential difference. A study was made to determine whether such gradients affected insect flight ac- tivity in the field. Observations were made in a small glade in a planta- tion of red, white and jack pine and a few white spruce. The electrostatic fields were determined by a probe and a vacuum tube electrometer and mapped as isopotential lines. Plots of the mosquito flight tracks revealed well defined and concentrated areas of flight. These flight areas coincided with the relatively more electrically positive centre of the glade, or in pockets of either positive or negative polarity. The following observations were made on three occasions in May, 1960 and two in May, 1961. Separate and confined groups of A. trichurus were seen in the glade. The insects did not hover but flew continuously in a clockwise direction. After approximately 15 minutes the groups began to merge and within an hour they formed a swarm, 2 m. wide, 13 m. long, and 1 m, deep and about 0.5 m. above the ground. The flights were from end to end of the swarm but not always in a clockwise direction. More males than females were present but only two matings were seen in the two years of observation. The existence of the swarm or flyaway invariably coincided with a steep potential gradient along the sides of the plot. When the gradients were small, males could be found throughout the plot in limited numbers -when conditions where conducive to mosquito flight. It appears that when _the gradients are steep, the mosquito’s flight patterns are channeled into areas of relatively positive polarity by gradients of negative polarity. When there was a flyway, the presence of swarm markers as described by Downes (1958) did not induce swarms or concentrations either in the large swarm area or outside of it. It was also noted that these particular Swarms occurred on days when there was a decided drop in pressure. This drop was followed first by a period of fluctuating pressure for up- wards of eight hours and then by a steep rise in pressure indicating a passage of a weather system. In recent years the use of synthetic fibre materials in the construc- tion of insect traps and nets has increased with little attention given to the 35 possibility that the electrical proprties of these materials might affect the efficiency of the traps. At Belleville it was found that with a rotary trap (Nicholls, 1960) one net consistently collected more hymenopterous parasites than did its counterpart. Inspection revealed that one net was a little higher than the other and as the arms of the trap revolved the higher the net struck a leaf of a nearby tree. The leaf transferred a charge to the net and this net had the smaller catch. When one net was artificially charged and the other one left uncharged as a control, the charged net collected only 39 per cent of all insects caught. This experiment showed that if a net should become charged accidentally, and it may become charged quite easily, it may have its efficiency lowered by about one-third. This factor could affect any data used in population studies. paeou Gace on the Application of Atmospheric Electricity to Biological Problems It is apparent that air ions and electropotential fields can cause bio- logical effects in insects. Inter- and intraspecific differences will be en- countered, but it is felt that some response to atmospheric electricity will be found in all biological activities. _ With our limited knowledge of the subject we can only speculate about its future in biology, but some intriguing questions come to mind. Is diapause influenced to some degree by the ion content of the air? The greatest ion level is in the summer and the level fails off in the winter months, The curve of the ion level plotted against time is similar in form to that of the annual photoperiod. There may be a ciose relationship be- tween the two factors in influencing the duration and onset of diapause. Does long-term exposure to aparticular level affect fecundity or longevity, and what is the mode of action? Are the biological effects of barometric pressure really due to the pressure changes per se, or is it a trigger me- chanism which permits the ion level to alter or initiate the response of the organism through physiological changes? Do insects respond to air ion density or electropotential in the space around them when they are at rest? Can the normal ionization level under most conditions play a sig- nificant role in competition or combination with other environmental fac- tors? If these questions are considered with a prejudiced viewpoint, con- vincing arguments to support the ion theory can certainly be developed. In the field of applied entomology the manipulation of the environ- ment might be considered. The site of charges on plants may determine where the eggs will be placed by the adults of pest species and by applying electrical fields the insects might be induced to place their eggs so that they are exposed to the attacks by parasites and predators. This type of environment manipulation may be possible only on a limited scale. Some interesting techniques in the modification of space charges re- sulted from the work of Vonnegut and Moore (1959) and Vonnegut et al. (1961). They were successful with a modest expenditure of energy in re- » versing the normal fair-weather electrical field for a distance of 10 km. or more down wind. The question arises: is it possible to set up a system of small wires at a height of 3-4 m. to produce an electrical field around a plot and so give a measure of protection to plants from insect attack wi- thin that field? Only the surface of this interesting subject has been touched and only hints have been revealed of the physiological importance of air ions and electropotentials. It may be that in the future insect population predic- tions might be compiled with greater accuracy by sampling the ion con- tent of the air at appropriate times. 36 Summary The effect of atmospheric electricity on insects has only recently been studied quantitatively. It has been suggested that the activity of foraging bees and the hostility of guard bees is increased by fiuctuations of atmos- pheric electricity. Rates of moulting and other activities in aphids have been correlated with increased ionic content of the air and changes in the activity of calliphorids and drosophilids with changes in the electrical field have been found. Oviposition rates and oviposition sites, progeny yields and developmental rates of Hymenoptera, Diptera, and Lepidoptera are apparently influenced by electrical fields. Observations during the past two years indicate that local potential gradients surrounding trees influence the flight of insects in general, and mosquitos in particular. Aedes trichurus Dyar seem to swarm in precise flyways bounded by steep gradients of electropotential in a forest glade, Markers do not induce swarming in less intense potential gradients though other factors are favourable. Though further work is needed, evidence indicates that charges accumulated by synthetic fabrics used in some insect traps may interfere with trap efficiency. Possible applications to insect control and theoretical investigations are discussed. Literature Cited CHALMERS, A. J. (1957). Atmospheric Electricity. Pergamon Press, London. DowngEs, J. A. (1958). Assembly and mating in the biting nematocera. Proc. 10th Int. Congr. Ent. 2 : 425-434. EDWARDS, D. K. (1960a). Effects of artificially produced atmospheric electrical fields upon the activity of some adult Diptera. Canad. J. Zool. 38 : 899-912. EDWARDS, D. K. (1960b). Effects of experimentally altered unipolar air ion density upon the amount of activity of the blowfly, Calliphora vicina R.D. Canad. J. Zool. $8 = 1079-1091. EDWARDS, D. K. (1961). Influence cf electrical field on pupation and oviposition in Nepytia phantasmasia Stkr. (Lepidoptera: Geometridae). Nature 191 : 976-998. HAINE, E. (1957). Periodicity in aphid moulting and reproduction in constant tem- perature and light. Z. angew. Ent. 40 : 99-124. Hicks, W. W. (1956). Air ion generation, separation, metering and physiological effects. J. Franklin Inst. 261 : 209-217. KORNBLUEH, I. H. and SpreIcHER, F. P. (1957). The difficulties encountered in evalu- ation of artificial ionization of the air. Intern. J. Bioclimatol. Biometeorol J, Part IV; Sec. C4 : 1-8. LEVENGOoD, W. C. and SHINKLE, W. P. (1960). Environmental factors influencing progeny yields in Drosophila. Science 132 : 34-35. LEVENGOoD, W. C. and SHINKLE, W. P. (1961). Progeny yields in Drosophila. Letters, Science 133 : 68, 115-116. Maw, M. G. (1961a). Behaviour of an insect on an electrically charged surface. Canad. Ent. 93 : 391-398. Maw, M. G. (1961b). Suppression of oviposition rate of Scambus buolianae (Htg.) (Hymenoptera: Ichneumonidae), in fluctuating electrical fields. Canad. Ent. 93 : 602-604. NICHOLLS, C. F. (1960). A portable mechanical insect trap. Canad. Ent. 92 : 48-51. Scuua, L. (1952). Untersuchungen tiber den einfluss meteorologischer elemente auf das verhalten der honigbienen (Apis mellifica). Z. Vergl. Physiol. 34 : 258-277. STEINER, L. F., RoHWER, G. G., AYERS, E. L. and CHRISTENSON, L. D. (1961). The role of attractants in the recent Mediterranean fruit fly eradication progress in Florida. J. econ. Ent. 54 : 30-35. VoNNEGUT, B. and Moors, C. B. (1959). Preliminary atempts to influence convective electrification in cumulus clouds by the introduction of space charge into the lower atmosphere. In Recent Advances in Atmospheric Electricity, pp. 317-331. Perga- mon Press, London. VoNNEGUT, B., MAYNARD, K., SYKES, W. G. and Moore, C. B. (1961). Technique for introducing low-density space charge into the atmosphere. J. Geophys. Research 66 : 823-830. Accepted for publication January 15, 1962 37 ll. REVIEWS THE EASTERN FIELD WIREWORM, LIMONIUS AGONUS (SAY) (COLEOPTERA : ELATERIDAE), IN SOUTHWESTERN ONTARIO’ J. A. BEGG Entomology Laboratory, Research Branch, Canada Department of Agriculture, Chatham, Ontario The eastern field wireworm, Limonius agonus { Sa the principal pest species of wireworm in southwestern Ontario, infests the light sandy soils in the counties near Lake Erie. Since these soils are most suitable for growing row crops, the greatest crop loss has been sustained by potatoes, tobacco, tomatoes, corn, sugar beets, and various vegetables. In some districts, heavy infestations of this wireworm greatly reduced the value of farm land. Cultural practices offered, for many years, the only practical means of reducing crop loss caused by wireworms. Short crop rotations generally controlled the wheat wireworm, Agriotes mancus (Say), the corn wire- worm, Melanotus spp., the flat wireworm, Aeolus mellillus (Say), and Ctenicera spp. The intensive cultivation practiced in southwestern On- tario, however, gradually increased infestation of L. agonus, because the female usually oviposits in loose soil. No progress was made in controlling this species until introduction of the new, synthetic, organic insecticides about 1947. Continued use of these materials as seed, planting-water, and broadcast soil treatments has now reduced most infestations to non- economic levels. The eastern field wireworm has caused little or no damage to any agricultural crop since about 1956. This article reviews the life history of L. agonus, and development of the control measures which have practically eliminated the species as an agricultural pest in southwestern Ontario. Taxonomic Position The eastern field wireworm has been placed in the family Elateridae, subfamily Pyrophorinae, tribe Lepturoidini, and, on the basis of larval characteristics (Glen et al., 1943; Glen, 1950), in the canus group of the genus Limonius Eschscholtz. Since first described as Hlater agonus by Say (1836) it has been placed in the following genera: Limonius Esch. ; Pheletes Kiesenwetter; and Nothodes LeConte. Van Dyke (1932) conten- ded that Pheletes Kies. should be considered a subgenus of Limonius Esch. and that Nothodes Lec. was a synonym for Limonius. Fall (1934) accept- ed Van Dyke’s nomenclature. 1Contribution No. 22, Entomology Laboratory, Canada Department of Agriculture, Chatham, Ontario; prepared at the invitation of the Publications Committee, Entomological Society of Ontario. Proc. Entomol. Soc. Ont. 92 (1961) 1962. 38 Say (1936) described a species closely related to the eastern field wireworm as LHlater ectypus. Horn (1879) made agonus a synonym of ectypus, as did Leng (1920) and Van Dyke (1932). Fall (1934) pointed out the error, listing four distinct characteristics for separating the two species. The eastern field wireworm, however, was known as Limonius ectypus (Say) until 1948 at the Chatham laboratory. It is very probable that references to Limonius (Pheletes, Nothodes) ectypus are really to L. agonus, since the former is a relatively rare in- sect. The eastern field wireworm has also been mistaken for Limonius (Nothodes) dubitans Lec. Thus, some papers referring to the eastern field wireworm may actually concern any one of three species. General Description Adults of the eastern field wireworm show the typical form of Ela- terid beetles and vary in length from 8 to 12 mm. The head and thorax are black, the latter often with a bronze lustre. The iegs and elytra vary from light to piceous brown. Long, dense pubescence on the dorsal surface tend to give the beetles a dull appearance. Dietrich (1945) gives a detailed description of the adult, and a key to the genus, Limonius Esch. The eggs are elliptical in shape, averaging 651, in length and 517 » in width. They are pearly white and glossy when laid; later the develop- ing embryo can be seen through the thin, flexible, nearly transparent shell. The larvae, which are elongate and subcylindrical in shape, and yel- low-brown in color, attain a maximum length of about 22 mm. Small larvae are usually lighter in color than when mature. Lancaster (1946) has prepared a key to larvae of the genus Limonius Esch. belonging to the canus group of Glen (1950). Pupae resemble the adult in size and shape, and are shiny white in color, with a waxy appearance. Distribution The eastern*field wireworm is found east of the 105th meridian in the United States (Lancaster, 1946), from northern Maine to southern Pennsylvania (Olson, 1946). Southern Ontario appears to be near the northern limits of the species. Van Dyke (1932) stated that with one exception the genus, Limonius Esch., is holarctic in distribution, and is found more frequently in valleys and open spaces. Rawlins (1940) found that the eastern field wireworm inhabits sandy soils almost exclusively, as was noted in fields with zones of heavy and light soils. In Ontario, a survey of the Elaterid fauna in the County of Middlesex showed that L. agonus predominates only in sand-type soils (Table 1). Observations made in many other localities in southwestern Ontario also demonstrated that suitable soils are usually infested with destructive popu- lations of the eastern field wireworm. The survey disclosed no difference in the numbers of L. agonus be- tween sod and cultivated fields in the sand soils. The cultivated fields sampled had not been continuously cultivated for any period of time. Fields which had been continuously cultivated had been treated for con- trel of wireworms, and therefore were not examined. The numbers of L. agonus were greater in cultivated than in sod fields in loam soils. The populations of other species of Elateridae generally decreased when sod fields were cultivated, as was noted by Fox (1961). The wireworm fauna was extremely low in numbers in the clay soils in Middlesex County, even in fields which had been cleared but not plowed. 39 Disappearance of native grasses in rundown pasture farms obviously could not be attributed to wireworms. TABLE 1—Species of Elateridae recovered in 20 sod and 20 cultivated fields in the sand-, loam-, and clay-type soils in Middlesex County, 1955-1960. Species Populations per Acre@ Sand Loam Clay Sod Cult. Sod Cult. Sod Cult. Limonius agonus (Say) 39,134 37,037 ike) eo Agriotes mancus (Say) aS yya tubs) SL 19,967 12,779 2,396 1,597 Aeolus mellillus (Say) 9,583 2,396 3,195 1,597 2,396 2,396 Melanotus spp. 5,591 5,591 1,597 799 Ctenicera spp. 3,195 Oestodes tenwicollis Rand 1,597 799 Unidentified 1,597 1,597 Totals 71,498 55,109 27,9538 21,564 5,591 3,993 aBased on 5 samples, 5 inches in diameter and at least 9 inches deep, dug at ran- dom in each quarter of a field. Life History and Habiis in Ontario The biology of the eastern field wireworm has been studied by Lacroix (1931-19386), Morrill and Lacroix (1937-1939), Greenwood (1945-1946), Beard (1946) and Kring (1955, 1957, 1959) in Connecticut; Kulash (1943) in Massachusetts; Rawlins (1940) and Olson (1946) in New York; and Begg (1956b, 1957) in Ontario. The following is based on the work of Begg (loc. cit.) unless noted otherwise. Adults remain in the pupal cell, 3 to 6 inches deep in the soil, until they emerge the following spring. From 1950 to 1955, the earliest emergence was April 20, 1955, and the latest May 10, 1953. Females emerge one to three days later than the first males. The beetles fly during the hottest part of the day, only when the sun is shining and the air temperature is 60° F. or higher. They immediately seek cover whenever the sun is obscured. Virgin females may be located by male activity; females are near when males circle on the ground waving the antennae. Females are usually found in crevices in the soil at this time, with only the abdomen protruding. Females fly only short distances until depositing most of their com- plement of eggs in the field in which they developed. The greatest spread of the species occurs in late May and early June, at which time females still contain numbers of eggs. Eggs are deposited 1 to 3 inches deep in the soil on either side of a tunnel made by the burrowing female, prefer- ably in loose soil. The rows of eggs are about one-half inch apart, and the eggs are approximately one-quarter inch apart in the row. The occurrence of the eastern field wireworm almost exclusively in light, sandy soils has been explained in part by Kring (1957). L. agonus beetles respond positively to maximum contact with sand, a thigmotatic response, and females choose for oviposition sands more easily manipu- lated with the mandibles. Vertical distribution of the eastern field wireworm was studied from 1950 to 1954 in a sandy-loam soil. Larvae overwinter 7 to 9 inches beneath the surface, usually near the junction of the top soil and pure sand sub- soil. There was no indication that below freezing temperatures adversely affected the larvae. Vertical movement toward the surface commences AO when the temperature at the overwintering depth approximates 50° F., usually the first to third weeks in April. They remain near the soil sur- face until late May and early June, when they slowly descend to the sum- mer depth of about 5 inches. The larvae often approach the soil surface ae in September, and return to the overwintering depth by late Octo- er. A further downward movement which occasionally occurred in August indicated that soil moistures of less than 12 per cent by weight are avoided by the eastern field wireworm. Larvae, however, have been found close to the soil surface during the summer months. Evidently, they had been attracted by the moisture in cabbage, cucumber and red beets. The horizontal movement of the eastern field wireworm in the soil has not been studied in detail. That this movement is considerable is indicated by the finding of 72 larvae under one potato plant, 47 at one cabbage plant, and 42 at one cucumber plant. As many as 142 wireworms have been recovered from one whole-wheat flour bait. Mature larvae pupate in the field in late July and early August, at a depth of about 6 inches. The mean pupal period is 15 to 16 days, under field conditions when temperatures at this time average 77°F. at the 3 to 6 inch depth in the soil. Adults remain in the pupal cell until emerging the following spring. In the laboratory, L. agonius adults can be stored in moist soil at 35° I’. for a considerable period of time. Those collected the previous summer usually survive until the following spring. Optimum temperature for mating is 70° to 80° F. Adults mate only when exposed to direct sunlight or artificial light, and survive longer when fed on honey. Few females deposit more than 50 eggs during a 24- hour period. Incubation period of eggs hatched in distilled water at 65° and 73° F. is 48 days and 24 days, respectively. Eggs generally can be stored in distilled water at 35° F. for about two months without adversely affect- ing viability. ) No progress was made in rearing larvae hatched in the laboratory until 1954, when larvae reared collectively on timothy seedlings for the first six weeks survived. Kring (1959) showed that the eastern field wire- worm requires a single feed of animal protein for survival. The species apparently is cannibalistic, because the nearest animal meal is probably another wireworm or egg in the oviposition tunnel. Although the normal larval stage of the eastern field wireworm apparently is three to five years, larvae have been reared to maturity in one year under laboratory conditions. Larvae which pupated in one year had six instars. The growth increment was linear rather than exponen- tial. As larvae which did not pupate within one year continued to moult, more than six instars can be expected. Larvae collected in the field and reared at temperatures approximat- ing those at the 3 to 6-inch level in the soil had two annual peaks of moulting, one in June and one in late July and early August. Since wire- worms cease feeding for short periods before and after ecdysis, these peaks might account for periods of inactivity noted in the field by Beard (1946). If the larvae moult a minimum of six times and an average of twice a year under field conditions, the minimum larval stage is three years. Some larvae, however, moult several times during a year without showing any increase in size. Doubtless this occurs in the field under adverse conditions, and results in extended larval periods. Al Estimating Wireworm Populations Begg (1959) reported that baits of whole-wheat flour dough about 1.5 inches in diameter placed 3 inches deep in the soil in experimental plots offers a simple method of estimating wireworm densities. When 95 per cent of the potatoes in treated plots were marketable, the numbers of larvae per bait generally averaged no more than one. Counts made by the baiting technique in different years or at dif- ferent times in the same year, however, are not directly comparable. Numbers of wireworms coming to a bait depend, in part, on larval ac- tivity, which, in turn, depends on soil and weather conditions, natural food supply and size of the larvae. Time of year also is important, be- cause the eastern field wireworm is attracted to baits only in the spring and early summer. Control Introduction of the new, synthetic, organic insecticides, which kill by contact action, offered for the first time positive means of controlling the eastern field wireworm. From 1948 to 1955, investigations at the Chatham laboratory showed that these materials, applied as seed, planting- water and broadcast soil treatments, were very effective in protecting agricultural crops from wireworms in southwestern Ontario. Seed Treatments Treating the seed of corn, sugar beets, cereals, beans and cucurbits with wettable powders of various chlorinated hydrocarbon insecticides practically eliminates feeding injury by the eastern field wireworm. The insecticide apparently protects the seed by both repelling and killing the larvae. Although the reduction in wireworm numbers in treated plots has never been greater than 25 per cent, the continued use of seed treatments since about 1950 has now reduced many infestations of the eastern field wireworm to non-economic levels. Aldrin’, dieldrin’, heptachlor* or lindane’ was recommended at the rate of 1 ounce of toxicant per bushel of corn or cereal seed until 1958 (Begg, 1955), when the dosage was reduced by one-half. This rate of application is adequate against the reduced populations of the eastern field wireworm now present in southwestern Ontario. Planting-water Treatments Transplanted crops are very susceptible to attack by the eastern field wireworm. One larvae per square foot of soil, a light population, can result in 6 or 16 wireworms attacking one tobacco or tomato plant, res- pectively. In the past, entire fields were often replanted three times be- fore a satisfactory stand could be obtained. Treating the planting-water with an insecticide for the control of wireworms was first tested at the Chatham laboratory in 1947. Armand (1948) used BHC® and chlordane’ for the protection of tomatoes with some success. Begg (1953, 1956b), continuing this study with still newer insecticides, found that planting-water treatments were highly effective against the eastern field wireworm. 21, 2, 3, 4, 10, 10-hexachloro-1, 4, 4a, 5, 8, 8a-hexahydro-1, 4-endo, exo-5, 8-dimethanonaphthalene. 31, 2, 3, 4, 10, 10-hexachloro-exo-6, 7-epoxy-1, 4, 4a, 5, 6, 7, 8, 8a-octahydro-1, 4-endo, exo-5, 8- dimethanonaphthalene. 41 (or 3a) 4, 5, 6, 7, 8, 8-heptachloro-3a, 4, 7, 7a-tetrahydro-4, 7-methanoindene. 5Gamma isomer of 1, 2, 3, 4, 5, 6-hexachlorocyclohexane (minimum purity, 99 per cent). . ®Mixed isomers of 1, 2, 3, 4, 5, 6-hexachlorocyclohexane. 1, 2, 4, 5, 6, 7, 8, 8-octachloro-3a, 4, 7, 7a-tetrahydro-4, 7-methanoiadan. ae Begg (loc. cit.) showed that lindane wettable powder at 0.25 ounce of toxicant per 45 gallons of planting water applied at the rate of 180 gallons per acre prevented wireworms from attacking tobacco, tomatoes and cabbage with no adverse effect on growth or flavor. Wettable pow- ders of aldrin, dieldrin and heptachlor were inferior to lindane when tested against heavy infestations of the eastern field wireworm. The use of emulsible formulations of insecticides in the planting water has been precluded by phytotoxicity of the solvents commonly in use. Planting-water treatments must be repeated each year a transplanted crop is grown in infested soil. The insecticide apparently protects the sus- ceptible underground stem, in part, by repelling the wireworms, since the ae of protection has always been greater than the kill of larvae would indicate. Broadcast Treatments The very high degree of control required to vrotect potatoes and other highly susceptible crops can be obtained only by killing wireworms. Potatoes, in contrast to seeded and transplanted crops, are subject to injury throughout the growing season. Larvae feed on the seed pieces and later tunnel the tubers, rendering them unmarketable. In 1947, Armand (1948) and Marshall (unpublished data) obtained good control of the eastern field wireworm attacking potatoes and other crops by treating the soil with BHC. This insecticide, however, was not suitable for general use, because it is disagreeable to apply and taints root crops for at least two years after application. Begg (1955, 1956b, 1959) developed soil treatments that may be used in potato land with no adverse effect on tuber quality. Chemical analyses, insect bioassays, and mammalian feeding trials made on potatoes grown in treated soil, indi- cated that insecticidal residues should not constitute a threat to the health of the consumer (Begg et al., 1960). The chemical analyses used for aldrin and heptachlor may not have detected ali the insecticide residues. Gannon and Biggar (1958) report that aldrin epoxidizes in the soil to dieldrin and heptachlor to heptachlor epoxide. When applied at 5.0 pounds of toxicant per acre for control of an exceedingly heavy population of the eastern field wireworm attacking early potatoes, dieldrin, heptachlor and aldrin prevented reinfestation for at least three years; chlordane gave protection for two years. Only diel- drin and heptachlor satisfactorily protected the tukers in the year of application. BHC containing 12, 90, and 99 per cent of the gamma isomer at 0.75 pounds of the gamma isomer, parathion® at 5.0 pounds, DDT” at 10 pounds, D-D mixture” at 17.0 gallons and ethylene dibromide at 3.0 gallons per acre gave inadequate control or were effective for only one to two years in small experimental plots. Of the insecticides tested, only BHC preparations produced an off-flavor in potatoes grown in treated soil (Begg, 1959). The off-flavour produced by high-gamma BHC was not as pronounced as with BHC containing 12 per cent of the gamma isomer. The data, Begg (loc. cit.), indicated that less insecticide is required and better control may be expected when broadcast soil treatments are applied in the year preceding a tuber crop. Apparently, some period of time is required for wireworms to contact a lethal concentration, since insecticides are not mixed evenly in the soil by standard cultural prac- 80, Q0-diethyl 0-p-nitrophenyl phosphorothionate. ®A complex mixture, mainly of 1, 1, 1-trichloro-2, 2-bis (p-chlorophenyl) ethane. Mixture of 1, 2-dichloropropane and 1,3-dichloropropene 43 tices. It was also observed that less insecticide is required to control light infestations of the eastern field wireworm. Broadcast soil treatments may be applied with crop sprayers, broad- cast equipment, or fertilizer drills as sprays, granulated formulations and insecticide-fertilizer mixtures. Surface treatments should be worked into the soil to a depth of 4 to 6 inches as soon as possible after application. No further cultural operation is required when a treatment is drilled be- neath the soil surface. Begg (1956a) found that, as an emergency measure, good control of the eastern field wireworm attacking potatoes can be obtained by ap- plying heptachlor as a band treatment after planting, on both sides and as close as possible to the seed pieces. Discussion of Control Measures Seed and planting-water treatments are particularly effective against the eastern field wireworm, because the larvae seldom attack stems of plants above the treated seed or area in the so:l. These measures have, on occasion, failed to control Aeolus mellillus (Say) and Melanotus spp. in southwestern Ontario. These wireworms, in contrast to the eastern field wireworm, react very quickly to changes in soil moisture and temper- ature, and attack plants very close to the soil surface. The eastern field wireworm is also very susceptible to broadcast treatments of insecticides. Reinfestation of treated fields is adversely affected by the long larval stage and the habit of the females in flying only short distances until depositing most of their complement of eggs in the field in which they were developed. It has been very noticeable that reinfestation of large fields has been much slower than in small, experi- mental plots. The wireworm population in one field treated with BHC in 1948 was practically nil six years later (Begg, 1954). There has been no evidence of population increases in any field treated for eradication of the eastern field wireworm. This suggests that, to date, no resistance has developed to the insecticides in current use. Literature Cited ARMAND, J. E. (1948). The control of wireworms in southwestern Ontario. Rep. ent. Soc. Ont. 78: 15-24. 1947. BEARD, R. L. (1946). Notes on feeding of wireworms. Jn Connecticut Agr. Expt. Sta. Bull. 501: 98-99. BrecG, J. A. (1953). Planting-water treatment for control of wireworms in tobacco. Rep. ent. Soc. Ont. 83: 54-57. 1952. BecG, J. A. (1954). Residual control of wireworms in flue-cured tobacco. Rep. ent. Soc. Ont. 84: 79-82. 1953. Becc, J. A. (1955). Control of wireworms in Ontario. Canad. Dept. Agr. Publ. 978. Becc, J. A. (1956a) Control of wireworms in early potatoes with heptachlor applied to the soil after planting. Rep. ent. Soc. Ont. 86: 45-48. 1955. Becc, J. A. (1956b). Biology and control of the eastern field wireworm, Limonius agonus (Say), in southwestern Ontario. M.Sc. thesis, Univ. Western Ontario, Lon- don. Brce, J. A. (1957). Observations on the life-history of the eastern field wireworm, Limonius agonus (Say) (Coleoptera: Elateridae), under laboratory conditions. Rep. ent. Soc. Ont. 87: 7-11. 1956. BeceG, J. A. (1959). Control of the eastern field wireworm, Limonius agonus (Say), in early potatoes in Ontario by application of insecticides to the soil. Canad. J. Plant. Sci. 39: 342-349. | Brecc, J. A., PLUMMER, P. J. G. and Konst, H. (1960). Insecticide residues in potatoes after soil treatments for control of wireworms. Canad. J. Plant Sci. 40: 680-689. Dietricu, H. (1945). The Elateridae of New York State. Cornell Univ. Agr. Expt. Sta. Memoir 267. 44 FALL, H. C. (1934). On certain North American Elateridae, old and new. J. New York ent. Soc. 42: 17-36. Fox, C. J. S. (1961). The distribution and abundance of wireworms in the Annapolis valley of Nova Scotia. Canad. Ent. 93: 276-279. GANNON, N. and Bicear, J. H. (1958). The conversion of aldrin and heptachlor to their epoxides in soil. J. econ. Ent. 51: 1-2. GLEN, R., KinG, K. M. and ARNASON, A. P. (1948). The identification of wireworms of economic importance in Canada. Canad. J. Res. 21, sect. D: 358-387. GLEN, R. (1950). Larvae of the Elaterid beetles of the tribe Lepturoidini (Coleoptera: Elateridae). Smithsonian Misc. Coll. Publ. 3987. GREENWOOD, D. E. (1945-1946). Wireworm investigations. In Connecticut Agr. Expt. Sta. Bull. 488: 344-347; Bull. 512: 56-59. Horn, G. H. (1879). Proc. Acad. Nat. Sci. 9: 14. KRING, pear oe A chamber for studies of site selection of Elateridae. Ent. News. 64: - : KRING, J. B. (1957). Oviposition response of Limonius agonus (Say) (Coleoptera: Elateridae) to sand particle size. Ann. ent. Soc. Amer. 50: 392-394. KRING, J. B. (1959). Predation and survival of Limonius agonus (Say) (Coleoptera: Elateridae). Ann. ent. Soc. Amer. 52: 534-537. KuLaAsH, W. M. (19438). The ecology and control of wireworms in the Connecticut river valley. J. econ. Ent. 36: 689-693. Lacrorx, D. S. (1931-1936). Tobacco insect studies. Im Connecticut Agr. Expt. Bull. 326: 419; Bull. 335: 261; Bull. 350: 494; Bull. 359: 380-383; Bull. 367: 140-147; Bull. 379: 104-109. LANCASTER, H. P. (1946). Larval determination of six economic species of Limonius (Coleoptera: Elateridae). Ann. ent. Soc. Amer. 39: 619-629. LENG, C. W. (1920). Catalogue of the Coleoptera of America, north of Mexico. John D. Sherman Jr., Mt. Vernon, N.Y. MorrELu, S. W. Jr. and Lacroix, D. S. (1937-1939). Tobacco insect studies. In Con- necticut Agr. Expt. Sta. Bull. 391: 96; Bull. 470: 466; Bull. 442: 46: OLSON, R. E. (1946). The biology of the eastern field wireworm, Limonius agonus (Say), in western New York State. M.Sc. thesis, Cornell Univ., Ithaca. RAWLINS, W. A. (1940). Biology and control of the wheat wireworm. Cornell Univ. Agr. Expt. Sta. Bull. 738. © SAY, T. (1836). Descriptions of new North American Insects. Trans. Amer. Phil. BoGz ns 62 167,171: VAN Dyke, E. C. (1982). Miscellaneous studies in the Elateridae and related families of Coleoptera. Proc. Calif. Acad. Sci., 4th series 20: 291-465. (Accepted for publication: January 19, 1962) O PEACH TREE BORERS (LEPIDOPTERA: AEGERIIDAE) IN ONTARIO’ H. R. BOYCE Research Station, Research Branch, Canada Department of Agriculture Harrow, Ontario Introduction The peach tree borer, Sanninoidea exitiosa (Say), and the lesser peach tree borer, Synanthedon pictipes (Grote and Robinson) , both indigenous to Ontario, are members of the family Aegeriidae. The hosts of the two Species appear to be limited to native and introduced representatives of the Rosaceae. Both species are major pests of the peach in Ontario. 1Publication No. 37, Research Station, Research Branch, Canada Department of Agriculture, Harrow, Ontario;prepared at the invitation of the Publications Committee, Entomological Society of Ontario. Proc. Entomol. Soc. Ont. 92 (1961) 1962 45 This review is based not only on relevant publications of the writer and others, but also on unpublished notes and observations by the writer. Its purpose is to familiarize the entomologist at large with broad aspects of the distribution, development and control of the two species. Snapp (1948) reported that the peach tree borer was described in 1823 by Say who placed it in the genus Aegeria. Since then the insect has had several designations and it is now assigned to the genus Sanninoidea. According to King (1917), the lesser peach tree borer was first re- corded from Pennsylvania in 1868 by Grote and Robinson as Aegeria pictipes. Since then it has been renamed several times and is now placed in the genus Synanthedon. Distribution and Hosts S. exitiosa.—In Canada, the insect has been mentioned in entomologi- cal literature for many years. Fyles (1898) reported that he collected adults from Spiraea salicifolia L. at Levis, Quebec and Fletcher (1902) reported the capture of a specimen at St. John, New Brunswick. Criddle (1925) reported that an adult was taken at Douglas Lake, Manitoba, and Swaine (1913) noted its presence at Isle Perrot, Quebec. It is evident therefore, that the species occurs from Manitoba to the Maritimes in eastern Canada. In British Columbia, Lyne (1913) reported that S. exitiosa Was injurious to peach and other stone fruits. Snapp (1943) reported that the peach tree borer occurs in most of the peach-growing areas of North America, but mainly east of the Rocky Mountains from the New England States to the Gulf of Mexico. Only one record of native hosts of the peach tree borer in Canada has been found, namely, Swaine (1913) reported that larvae probably of Aegeria exitiosa, had destroyed many trees in a grove of wild cherry at Isle Perrot, Quebec. In the United States, Snapp (1943) reported that the native hosts were thought to be wild cherry and wild plum. In addition he noted that the species was reared from Prunus hortulana Bailey and Prunus serrulata sachalinensis Makino. Chamberlain and Dustan (1954) reported that the peach tree borer is an important pest of peach in Canada, and that occasional infestation of plum, cherry and apricot occurs. Stone fruits attacked in the United States were reported by Snapp (1943) as peach, plum, prune, cherry, nectarine, apricot and almond. S. pictipes.—The lesser peach tree borer, unlike the peach tree borer, does not occur in British Columbia, and the former is of economic signi- ficance only in Ontario. Undoubtedly, the incidence of S. pictipes on na- tive hosts in Canada may be expected to extend beyend Ontario. Fletcher and Gibson (1909) reported that S. pictipes was collected at Levis, Que- bec in 1908 and King (1917) that the species was well distributed over the eastern half of the United States. Canadian literature contains no reference to native hosts of the lesser peach tree borer. The writer (unpublished) reared the species from knots caused by the black-knot fungus, Dibotryon morbosum (Schw.) Th. & Syd. which was obtained fron an unidentified species of wild plum in the vicinity of St. Catharines, Ontario. King (1917) listed as native hosts: wild black cherry, Prunus serotina Ehrh.; bird cherry, P. vensylvanica L. ; wild plum, P. americana Marsh.; beach plum, P. maritima Marsh.; and juneberry, Amelanchier canadensis (L.) Medic. No doubt some of the above plants are attacked in Ontario. King (1917) reported cultivated hosts in the United States to be peach, plum and cherry, the first mentioned being a favoured host. There have been numerous reports of injury to peach in Ontario, but none re- AG garding cherry and plum. On one occasion, the writer (unpublished) reared large numbers of adults from cultivated plum trees, the trunks of which had been severely damaged by winter injury. The orchard is lo- cated near Harrow, Ontario. Descriptions The several stages of Sanninoidea exitiosa and Synanthedon pictipes are not always easy to relate. It is unlikely that the female of S. exitiosa (Fig. 1) will be wrongly identified because the blue-black forewings and orange band on the abdomen make it so distinctively different. The male of S. exitiosa (Fig. 2) closely resembles both sexes of S. pictipes, but ex- Fic. 1. Adult female of S. ewxitiosa. Fic. 2. Adult male of S. exitiosa. Fic. 3. Eggs of S. exitiosa on peach leaf. Fic. 4. Mature larvae of S. exitiosa exposed in burrow. Fic. 5. Pupa of S. exitiosa. Fic. 6. Cocoon of S. exitiosa with soil particles incorporated. AT cept in rubbed or greasy specimens can usually be distinguished from the latter by the narrow yellow bands on the posterior margin of each abdominal segment. The adult female of S. pictipes (Fig. 7) has light yellow bands on the distal margins of the second and fourth abdominal segments as does the male (Fig. 8), but the yellow band frequently is absent on the dorsal surface of the fourth abdominal segment of the fe- male. Males of S. pictipes can be distinguished readily from the females by the presence of finely tufted antennae. Fic. 7. Adult females of S. pictipes.. Fic. 8. Adult male of S. pictipes. Fic. 9. Eggs of S. pictipes on cankered area. Fic. 10. Mature larva of S. pictipes. Fig. 11. Pupa of S. pictipes. 48 The eggs of S. exitiosa and S. pictipes are very similar in colour and appearance. They are reddish-brown to brown in colour, ellopsoidal in shape when seen from above, and have slightly depressed centres. Arm- strong (1940 and 1943) reported measurements of eggs of both species in Ontario, (Figs. 3 and 9) which indicate that those of S. exitiosa average 0.035 mm. longer and 0.03 mm. wider than those of S. pictipes. The larvae of S. exitiosa and S. pictipes (Figs. 4 and 10) are readily distinguishable only in the late instars. The diagnostic characters for separation of mature larvae have been reported by Peterson (1951). King (1917), reported measurements of the head widths of the larvae of S. pictipes in each of the six instars, but apparently no comparable informa- tion has been published for S. exitiosa. Smith (1951) separated the six instars of the two species on the basis of head capsule measurements and morphological characters, the details of which were to be reported later. It appears that a detailed investigation to determine reliable diagnostic characters for separating all larval instars of the two species is still re- quired. Pupae of S. exitiosa and S. pictipes (Figs. 5 and 11) may be separated readily by the generic descriptions of Mosher reported by King (1917). Good descriptions of the developmental stages of the lesser peach tree borer and of diagnostic characters distinguishing it from the peach tree borer and the western peach tree borer, Sanninoidea opalescens=(exitiosa graefi (Hy Edwards) ), were reported by King (1917). Less complete, but valuable data on certain stages of the peach tree borer, were reported by Gossard and King (1918) for northern Ohio, by Snapp (1948) for the southeastern United States, and by Armstrong (1940) for Ontario. Life-Histories and Habits Armstrong (1940) investigated the life history and habits of S. exitiosa in the Niagara peninsula from 1935 to 1939, and reported (1943) similar, less extensive studies of S. pictipes at Vineland Station, Ontario, from 1937 to 1941. S. exitiosa overwinters in the second to sixth instars as apparently does S. pictipes. King (1917) reported that S. pictipes in the second to sixth instars passed the winter in northern Ohio in deep areas of their burrows, or in loose cells of frass and silk. For hibernation, larvae of S. exitiosa construct a rough cocoon which may be located on the trunk in gummy exudations, or in the burrows. In Ontario, pupation of S. pictipes occurs from late April until the middle of August. The mature larva constructs a cocoon of bark and silk just underneath the surface of the feeding area. The peach tree borer larvae construct similar cocoons (Fig. 6) composed of wood, bark and earth which are usually located in the soil within three inches of the trunk of the tree. Larvae of this species mature from the middle of June until early August. Some, however, require two years to reach maturity. Armstrong (1940) reported that adults of S. exitiosa begin to emerge during the second week of July at Vineland Station, Ontario. In south- western Ontario, Boyce (1960) reported that adults have emerged as early as June 29. In the southermost portion of Essex County, adults of S. exitiosa usually begin to emerge about one week earlier (Fig. 12) than in- dicated for Vineland Station by Armstrong (1940). Emergence of adults of the lesser peach tree borer has been noted as early as May 20 in Essex County, but more frequently they begin to emerge (Fig. 13) during the last week of May. Data reported by Arm- strong (1943) show that the time of emergence of the adults of S. pictipes at Vineland Station approximates that of Essex County. 49 Rig. 12. PAG. AS. 60 on Oo fS oO NO.OF MOTHS EMERGING Dw) Oo O O fe) 8 IS JULY 22-29 be) le 9 AUG SEPT Emergence of peach tree borer adults from 50 trees in 1956, Harrow, Ontario. iS 26 2 IS 60 N OW bh @)) O .@) oO .@) NO.OF MOTHS EMERGING fe) 2| 28 4 MAY AB eee JUNE 10. 167235 430 6 JULY Fo eyrd Sree ie RS AUG SERE Ig Emergence of lesser peach tree borer adults from 50 trees in 1957, Harrow, Ontario Adults of both species usually copulate during the morning of the day that they emerge from the pupae. However, Armstrong (1940) reported that in cool weather males of S. exitiosa do not fly and copulation may be delayed as long as three days. Similarly, it has been reported by King 50 (1917) that when weather is unfavourable S. pictipes females have re- mained unmated for two and one-half days. Males of both species are strongly attracted to the females by an emission from scent glands. Armstrong (1943) reported that since isolated females of S pictipes would not oviposit he was unable to estimate accurately the reproductive capacity of the female. Dissection of six females showed an average of 332 fully developed eggs in the ovaries. Similar dissections reported by King (1917) showed an average of 223 fully developed eggs in the ovaries of 10 females, and many undeveloped eggs which were not counted. Armstrong (1940) reported that both fed and unfed females of S. exitiosa oviposited readily when confined individually. Unfed moths laid an average of 478 eggs but those fed with a weak cane sugar solution, laid an average of 653 eggs. The eggs of the peach tree borer may be laid singly or in groups on the ground, or on the trunk and foliage of the peach. King (1917) and Armstrong (1948) reported that eggs of the lesser peach tree borer were deposited singly in cracks and crevices of wounds and cankers in the bark of the trunk and branches, and that females were strongly attracted to gummy, damaged areas on the trees. Armstrong (1940) reported that eggs of S. exiticsa always hatch dur- ing the night, and Snapp (1943) reported that eggs usually hatch during the night or in the early morning, although he had observed some hatching between 8 a.m. and 5 p.m. The newly hatched larvae of the peach tree borer were reported to be negatively heliotactic and positively geotactic by both Armstrong (1940) and Snapp (1943). These tactic responses cause the larvae to concentrate at the base of the tree, usually near the soil surface, where they burrow directly into the bark. It appears that the newly hatched larvae of the lesser peach tree borer though negatively heliotactic, are positively stereotactic; they concentrate, therefore, in protective cracks and crevices all over the tree, where they penetrate to the inner bark, particularly where callus tissue is present. In Ontario, no evidence shows that S. exitiosa or S. pictipes develops more than one brood of moths per year. In some seasons in Essex County adults of S. pictipes tend to increase after a decrease during the latter half of July. Since King (1917) and Rings (1956) have reported the occurrence of a partial second brood in northern Ohio, it is possible that this may also occur in the southernmost portion of Ontario. Damage and Infestation The lesser peach tree borer injures the tree by extensive tunnelling in the inner bark, at any point where larvae can become established. Their feeding on living callus tissues at the edges of suitable wounded areas, and in those areas infested in successive seasons causes rapid destruction of large areas of bark. After several years of such attack limbs become completely girdled and die. When the main crotch is severely attacked (Fig. 14) the entire tree may soon die. It has been reported (Chamber- lain and Dustan, 1954) that cankers caused by the fungus, Valsa cincta Fr., are favorite points of attack by this insect. Although the borers do not cause peach canker, they may help to spread the disease by injuring tissues, thereby providing an infection court for the entry of the fungus. Rings (1960) reported on the number of lesser peach tree borers occurring in various types of wounds and indicated that the edges of old borer feed- ing sites were attacked very heavily. 51 The peach tree borer larvae mainly attack the basal area of the trunk — just at or slightly above ground level. They feed in irregular tunnels in the inner bark and outer wood of both the trunk and the main roots (Fig. 16). Large quantities of gum, in which frass is usually embedded, are exuded Fic. 14. Extensive feeding area of S. pictipes larvae in badly cankered crotch. in the injured areas. Armstrong (1940) reported that peach trees older than about eight years can withstand the attack of several borers without any apparent detrimental effect on growth or yielding capacity. Newly planted trees and those less than three years old are often killed by the extensive feeding of the larvae (Fig. 15). Trees less than three or four years old are seldom attacked by the lesser peach tree borer but, as they grow older, greater numbers of them become infested by both species. The result is an increasing rate of de- bility and death unless adequate control measures are applied. | Estimates of loss caused by larvae of the two Aegeriid borers ap- parently have not been expressed in other than descriptive terms. Ac- — cordingly, no valid dollar values may be allotted to various degrees of in- festation. This situation is understandable because of difficulties of evalu- ating the contributions to tree mortality of the complex of factors in- volved. In any particular situation, winter injury, faulty cultural and pruning practices, borer damage, and canker-causing fungi each alone or interacting with others, may cause weakening or death of the trees. The following abbreviated history of borer infestations in Ontario is excerpted from reports published since 1902. Lochhead (1903) reported that peach tree borers (Sannina exitiosa) were very numerous, especially in the Niagara district, and that many young trees nianted in 1902 were injured. Lochhead (1905) reported that orchardists at Leamington and several other locations experienced trouble with peach borers. Treherne (1912) reported that the peach tree borers (S. exitiosw) was again attract- ing the attention of growers; that 80 per cent of four-year old trees were atacked in one orchard; and that this insect had been considered a serious 52 pest ten years previously when a part of the general control routine was to excavate larvae from the crown of the trees. The increase was as- cribed to the discontinuance of removing borers, because of the increase in the cost of labor. BENS Sir Re ORR . BGs iglie Paoe of ee of S . exitiosa larvae on a young peach tree. Caesar (1914) reported that Aegeria pictipes occurred in cankers, caused by “Gummosis’”’ disease, on the branches of many peach trees in the Niagara district and that injury by S. exitiosa occurred in the new peach districts of Elgin and Norfolk Counties. This report appears to be the earliest recognition in Ontar.o of the lesser borer as a pest of economic importance. Ross (1916) and Caesar (1916) reported that Aegeria pic- tipes, in association with cankers on peach in the Niagara district, was causing extensive increases in the size of the damaged areas. Caesar (1916) also mentioned that the insect had become very prevalent in that district while the peach tree borer was causing much damage in Norfolk County. Then, Noble (1917 and 1918) reported that the lesser peach tree borer had ruined some orchards in Essex County in 1916, and that the peach tree borer was increasing in abundance in 1917, in the same area. Ross and Caesar (1922) reported that in 1921 S. exitiosa was much more injurious in Lambton County, than in other Ontario peach growing sec- tions. The above reports indicate that both species of borers were recog- nized as pests of economic importance in the major peach-growing sections Dd of the province. In general, it appears that S. exitiosa was considered to be the more important of the two. For some years after 1921, little or no mention was made of the Aegeriid borers as pests of peach in Ontario. Ross and Putnam (1934) re- ported that the peach tree borer occurs in all parts of the Niagara district, but that it was destructive only occasionally in relatively few orchards. In addition, they reported that the lesser peach tree borer may be found working in cankers, and that the most that can be said of it as a pest of peach is that it is a factor in aggravating and increasing the size of cank- kers. However, Twinn (1936 and 1937) reported that the peach borer, S. exitiosa, had become more prevalent and injurious in the peach-growing sections of southern Ontario This increase stimulated research by Arm- strong at Vineland Station and Grimsby on the life history and control _of the peach borer. From 19357 to 1948 infestations by both species were net particularly serious, but after 1948, Boyce (1959) reported that the lesser peach tree borer was particularly troublesome in Essex County. Then, following widespread adcption of chemical control recommended by Armstrong and Boyce (1958), infestation by the lesser peach tree borer steadily decreased to such a po.nt that by 1961 severely infested orchards couldn not be found, in which to continue chemical control experiments. Fic. 16. External evidence of injury by S. ewitiosa larvae at the base of a peach tree. Natural Limiting Faciors Armstrong (1940) reported that a high natural mortality of immature stages of the peach tree borer must exist. In a field experiment, in which 51 females were distributed in wire cone cages around the bases of 12 trees, approximately 15,500 eggs were laid, and during the next two years 66 adults emerged, that is one moth per 235 eggs. Thus, mortality was 99.6 per cent. 54 Armstrong (1943) reported that in 1941 and 1942, no adults of S. pictipes were obtained from totals of 762 and 610 eggs placed on the un- injured bark of clean limbs but that when eggs were placed on natural cankers adults were recovered to the extent of 5.4 per cent. Further, if eges were placed on the surface of artificial wounds, or under the edges of the bark of such wounds, mortality, as indicated by recovery of adults was 98.5 and 97.0 per cent, respectively. He did not indicate what. inhibit- ing factors were operating against the lesser peach tree borer, but sug- gested that newly hatched larvae died in the absence of shaded, protected areas where they could penetrate rapidly beneath the bark surface. Parasites of the peach tree borer and of the lesser peach tree borer have received practically no attention in Ontario. Armstrong (1940) re- ported that Microbracon sanninoidae Gahan was reared from cocoons and Phaeogenes ater Cress. from borer larvae. Parasitism by these two species was 2.5 per cent in 1937, but nil in 1935, 1986 and 1938. Such data sug- gest that parasitism of the insect is of little importance. Snapp (1943) reported that Telenomous quaintance: Girault, Micrebracon sannioideae Gahan, and Anthrax lateralis Say were common parasites of the peach tree borer in central Georgia, also that field mice and rats are the most important predators of the peach tree borer in central Georgia. Other predators were two species of ants, an Attid spider, chrysopid larvae, pigs, moles and skunks. Doubtiess a more complete study would reveal a degree of predation in Ontario. No information appears to be available on parasites or predators of the lesser peach tree borer in Ontario. The writer (unpublished) has occasionally noted evidence of attack by wocdpeckers. King (1917) report- ed the parasite Microbracon dorsator Say as attacking larvae in cocoons in Ohio. He also reported that ants attacked larvae and recently emerged adults, and that the wood pewee caught female moths when they were flying near the trees. Control Early attempts to control S. exitiosa largely consisted of digging the larvae out of their burrows in the spring and fall. Lougheed (1906) report- ed additional measures such as mounding the trunks in early summer with earth to compel moths to deposit eggs some distance up the trunk. The idea was to increase the opportunity for birds and predaceous insects to devour young larvae before they could bore into the trunk. Wrapping the trunk with tarred paper in July, or making two applications of a thick wash composed of two quarts of strong soap, a half pint of crude carbolic acid and enough lime and clay to make a thin paste, were reported as methods that were partly successful, especially if used in addition to “worming”’. Caesar and Howitt (1916) reported similar control methods, which included the use of special tree protectors made in the United States. Although Caesar (1930) reported that the usual method of control was to cut out the borers in late May or early June and again in October, he in- dicated that a simpler, more effective method was to apply paradichloro- benzene crystals in a narrow ring around the tree, avoiding contact with the bark and mounding with soil during the first two weeks of September. Caesar (1930) reported that some control of S. pictzpes could be attained by removing cankered branches where possible, by cleaning out the re- maining cankers before the middle of May, with a drawknife and jack- knife, and then by painting with white lead. Armstrong (1945) reported that in tests since 1938 ethylene di- chloride emulsions had shown promise in controlling the peach tree borer. 55 = In Norfolk County and Niagara Peninsula in 1942 to 1944 five to 10 per cent emulsions of the chemical reduced borers by 90 to 100 per cent, with no injury to the trees. Severe injury to trees occurred, however, in western Ontario, when 15 to 25 per cent emulsions were applied. Armstrong noted that trees treated with standard rates of paradichlorobenzene in Norfolk County in September 1943, were severely injured whereas those treated with the correct ethylene dichloride mulsions were not. A consistent advan- tage of ethylene dichloride over paradichlorobenzene, is that it is volatile at lower temperatures than ,is the latter chemical, and therefore, unlike paradichlorobenzene, can be applied with good effect after harvest. Arm- strong (1949) reported revised recommendations for the use of ethylene dichloride emulsions, with particular reference to dosages for trees in re- lation to their age, and to correct placement of the chemical. After the general adoption of ethylene dichloride emulsions, good fruit growers experienced little damage by the peach tree borer. Mostly because the lesser peach tree borer was considered to be a problem secondary to peach canker, no attention was paid to chemical control of the pest in Ontario until several years after such investigations were under way in the United States. Smith (1951) showed that DDT was less effective against the lesser peach tree borer than against the peach tree borer, and that parathion was more effective than DDT against both borers. Smith (1952) reported that three applications of 2 lb. of 15 per cent parathion wettable powder were equally effective in controlling both species of borer in commercial orchards. Rings (1952) reported results closely confirming those of Smith (1952). Because of the marked increase in infestation and damage done by the lesser peach tree borer, particularly in Eeeex County, Ontario, research on chemical control of the pest was begun at Harrow in 1954. Boyce (1959) reported on experiments with endrin’, dieldrin’, parathion, or 15 per cent parathion wettable powder plus 50 per cent malathion emulsifiable liquid, from 1955 to 1957. The treatments, except those with dieldrin, were equal- ly effective in reducing the numbers of lesser peach tree borer larvae in infested areas. Also, they reduced infestation and promoted rapid healing of badly-injured areas. It was concluded that the combination of actual parathion at 0.27 to 0.31 Ib. with actual malathion at 1.20 to 1.32 lb., per acre was a preferred treatment because of less hazard to spray operators and least dangerous residues on peach fruits. Armstrong and Boyce (1958) reported control of the lesser peach tree borer with 15 per cent parathion wettable powder 1 lb. together with 50 per cent emulsible malathion, 1 pint in 100 gallons of water. Three applications were advised, the first 5 to 10 days after the second curculio spray, the second three weeks later and the third three weeks after the second. In addition, 20 per cent emulsi- ble endrin at 1 quart per 100 gallons of water was recommended for use only on young, non-bearing trees. Since mixed populations of S. exitiosa and S. pictipes frequently oc- cur in the same trees, it would be of considerable advantage if spray materials suitable for control of the lesser peach tree borer would also control the peach tree borer. In the event that such were found, a separate control measure with ethylene dichloride could be discontinued. Boyce (1960) reported on experiments conducted in 1958 and 1959 at Harrow, Ontario, which showed that actual endrin 4.0 ounces, or malathion 5.5 21, 2, 3, 4, 10, 10 - hexachloro-exo-6, 7-epoxy-1, 4, 4a, 5, 6, 7, 8, 8a-octahydro-1, 4, 5, 8-endo-endo- dimethanonaphthalene. 31, 2, 3, 4, 10, 10-hexachloro-exo-6, 7-epoxy-1, 4, 4a, 5, 6, 7, 8, 8a-octahydro-1l, 4, -endo-exo-4, 8-. dimethanonaphthalene. 56 ounces plus parathion 1.2 ounces, or Thiodan‘ 4.0 ounces per acre, for each of three applications, were equally effective in reducing populations of larvae of the two species, but that the low incidence of the peach tree borer in both years left some doubt of the value of the treatments in the event of higher levels of infestation. Although peach growers in Ontario now have effective measures for the control of the peach tree borers, research must continue with new materials and new methods as they become available. Past experience in the chemical control of many pests has shown that resistance may arise. More work on the ecology, and on diagnostic characters of the younger larvae of both species obviously is needed. Acknowledgements The author is indebted to G. G. Dustan, Canada Department of Agriculture, Research Branch, Research Laboratory, Vineland, for the loan of negatives for Figs. 1-5, 7, 9, 14, 15 and 16. Literature Cited ARMSTRONG, T. (1940). The life history of the peach borer, Synanthedon ewitiosa Say, in Ontario. Sci. Agr. 20: 557-565. ARMSTRONG, T. (1943). Notes on the lesser peach borer, Synanthedon pictipes G. & R., in Ontario. Rep. ent. Soc. Ont. 63: 52-57. ARMSTRONG, T. (1945). Ethylene dichloride for the control of the peach tree borer. Canada Dept. Agr. Sci. Ser., Div. Ent., Proc. Pub. 34: 1-2. ARMSTRONG, T. (1949). Control of borers attacking peach trees. Canada Dept. Agr. Sel oecrv. Pmt. Divy.,-e roc. Pub: 172: 1-8: ARMSTRONG, T. and Boycn, H. R. (1958). Control of borers attacking peach trees in Ontario. Canada Dept. Agr. Sci. Ser., Ent. Div., Pub. 1039: 1-6 Boyce, H. R. (1959) Chemical control of the lesser peach tree borer, Synanthedon pictipes (G. & R.) (Lepidoptera. Aegeriidae), in Essex County, Ontario. Canad. J: Plant Sci. 39: 75-79. Boycr, H. R. (1960). Insecticidal control of Aegeriid borers attacking peach. Proc. North Central Branch Ent. Soc. Amer. 15: 45-47. CHAMBERLAIN, G. C. and DusTAN, G. G. (1954). IN Diseases and insect pests of stone fruits in Canada. Canada Dept. Agr., Pub. 915: 23-26. CAESAR, L. (1914). Insects of the season in Ontario. Rep. ent. Soc. Ont. 44: 52. CAESAR, L. (1916). Insects of the season in Ontario. Rep. ent. Soc. Ont. 46: 30. Camsar, L. (1930) IN Insects attacking fruit trees. Ont. Dept. Agr. Bull. 356: 62-66. CAESAR, L. and Howitt, J. E. (1916). IN Peach growing in Ontario. Ont. Dept. Agr. Bulkegir: A143. CRIDDLE, N. (1925). The entomological record, 1924. Rep. ent. Soc. Ont. 55: 90. FLETCHER, J. (1902). Entomological record, 1901. Rep. ent. Soc. Ont. 32: 109. eae and GIBSON, A. (1909). Entomological record, 1908. Rep. ent. Soc. Ont. a ; FYLEs, Rev. T. W. (1898) Notes on the season 1897. Rep. ent. Soc. Ont. 28: 72. GOSSARD, H. A. and KiNG, J. L. (1918). The peach tree borer. Ohio Agr. Exp. Sta. Bulle329 O7-8 7. Kine, J. L. (1917). The lesser peach tree borer. Ohio Agr. Exp. Sta. Bull 307: 399-448. LOCHHEAD, W. (1903). The insects of the season. Rep. ent. Soc. Ont. 33: 67. PoE, W. (1905). Injurious insects of the season 1904. Rep. ent. Soc. Ont. 35: LOCHHEAD, W. (1906). Injurious insects of 1905 in Ontario. Rep. ent. Soc. Ont. 36: 134. NOBLE, J. W. (1917). Reports on insects of the year. Rep. ent. Soc. Ont. 47: 24. NOBLE, J. W. (1918). Report on insects of the year Rep. ent. Soc. Ont. 48: 28. PETERSON, A. (1951). Larvae of insects, Pt. J: 128-129. 46 7, 8, 9, 10, 10 hexachloro-1, 5, 5a, 6, 9, 9a-hexahydro-6, 9-methano-2, 4, 3-benzo-dioxathiepin 3-oxide. Niagara Brand Chemicals, Burlington, Ont. a7 RINGS, R. W. (1953). Life history and control of borers attacking peach trees. Proc. Ohio Hort. Soc. 106: 68-79. Rines, R. W. (1956). Insect and mite pests of peaches in Ohio. Ohio Agr. Exp. Sta., Res. Bull. 768: 38-42. Rincs, W. A. (1960). The biology and control of ine lesser peach tree borer. Proc. Ohio State Hort. Soc. 113: 71-80. Ross, W. A. (1916). Reports on insects of the year. Rep. ent. Soc. Ont. 46: 22. Ross, W. A. and CAESAR, L. (1922). Insects of the season in Ontario. Rep. ent. Soc. Ont: 57 Ab: Ross, W. A. and PUTMAN, W. (1934). The economic insect fauna of Niagara peach orchards. Rep. Soc. Ont. 64: 36-41. SmITH, E. H. (1951). Control of peach tree borer and lesser peach tree borer. J. econ. Ent. 44: 685-690. SMITH, E. H. (1952). Control of peach tree borer and lesser peach tree borer. J. econ. Ent. 45: 611-690. SNAPP, O. I. and THompson, J. R. (1948). Life history and habits of the peach tree borer in the southeastern United States. United States Dept. Tech. Agr. Bull. 854: 1-24. cs SWAINE, J. M. (1913). Notes on some forest insects of 1912. Rep. ent. Soc. Ont. 43: 88. TREHERNE, R. C. (1912). Reports on insects of the year. Rep. ent. Soc. Ont. 42: 23. TWINN, C. R. (1936). A summary of insect conditions in Canada in 1935. Rep. ent. soc. Ont. 66 89. TWINN, C. R. (1987). a summary of the insect pest situation in Canada in 1936. Rep. efits 50.7 Ont. 675. ol Accepted for publication J anuary 16, 1962 8) A REVIEW OF THE HISTORY AND BIOLOGY OF THE EUROPEAN PINE SHOOT MOTH, RHYACIONIA BUOLIANA (SCHIFF.) (LEPIDOPTERA : OLETHREUTIDAE) IN ONTARIO’ P. J. POINTING AND G. W. GREEN Forest Insect Laboratory, Department of Forestry, Sault Ste. Marie, Ontario Introduction The European pine shoot moth is the most destructive insect affecting hard pine plantations in southern Ontario (Watson, 1947), and ranks as one of the most destructive of the introduced forest insect pests. Its attack on red pine, Pinus resinosa Ait., the most desirable, and until re- cently the most frequently planted timber tree, is so severe that planting of this species can no longer be recommended within the pest’s range. History and Distribution The shoot moth was first reported in North America in 1914 (Busck, 1914), when it was reared from severely infested Scots pine, P. sylvestris L., growing on Long Island, New York. Thirty-two infested nurseries or plantations in nine states from Pennsylvania to Illinois were found dur- in an intensive survey in 1915 (Busck, 1915). It was generally concluded that the infestations had resulted from separate, repeated, recent impor- tations from Europe. Votite (1957) reported two periods of widespread shoot moth damage in Holland from 1897 to 1901, and again from 1904 to 1910; the original introduction into the United States was probably 1Contribution No. 829 Forest Entomology and Pathology Branch, Department of Forestry, Ottawa, Canada; prepared at the invitation of the Publications Committee, Entomological Society of Ontario. Proc. Entomol. Soc. Ont. 92 (1961) 1962 58 made when nursery stock attacked during these periods was subsequently shipped to North America. For almost two decades little reference was made to the shoot moth in the United States, then as its importance as a pest of the native red pine, was recognized, extensive biological and control studies were undertaken (Hamilton, 1931; Friend and West, 1933, 1934; Friend and Plumb, 1938; Stearns, 1953; Connola et al., 1954; Miller and Neiswander, 1955; Butcher and Haynes, 1958, 1959, 1960). By 1950 the shoot moth was severely damaging pine plantations as far west as Wis- consin. The shoot moth was first reported in Ontario in 1925 at Windsor, where the Division of Foreign Pest Suppression intercepted and quaran- tined a shipment of infested nursery stock from Holland (McLaine, 1926). Later the same year, specimens of the pest, which was virtually to ring the death knell on red pine plantations in southern Ontario, were observed first, rather appropriately, in Prospect Cemetery, Toronto, and later at eight additional points in the Toronto area. The inauguration_of the per- mit system of importation on September 1, 1923, made possible the re- inspection of all subsequent imports (94 in all) that revealed the pest in nurseries and private grounds at Bowmanville, Fonthill, Ridgeville, Guelph, and St. Catharines by October, 1925, and at 45 localities by 1926 (McLaine, 1927). Hutchings (1926) believed that the shoot moth had already been established in Ontario for 12 years or more, and hence its probable date of introduction into Canada would correspond to that in the United States. sie) Z ee 52102) oreo, © TA V 30 ~~, ° -10 MEDINA @ LEGEND Wyn NORTHERN EXTENT OF CONTINUOUS SHOOT MOTH DISTRIBUTION @@@G@O@O@G®@ PERMANENT SHOOT MOTH COLLECTION POINTS OOOOOCOO ISOLATED SHOOT MOTH COLLECTION POINTS LAKE ERI : ; MEAN EXTREME MINIMUM ISOTHERMS (°F) Fic. 1. The distribution of the European pine shoot moth in Ontario In conjunction with the inspections of pine plantations, eradication measures met with indifferent success. Despite a drop in infestation from 2.6 per cent of the trees inspected in 1926 to 0.4 per cent in 1929 (Shep- 59 pard, 1929), by 1931. infestations were general in planted trees along the north shore of Lake Erie in Welland County. Increased efforts failed to stop the extension of infestations in the Niagara Peninsula, and re- coveries at many points in southwestern Ontario were traceable to the transfer of infested nursery stock (Sheppard, 1933). The cold winter of 1933-34 forced the shoot moth infestations to recede from northern areas, but subsequent re-infestations extended the northern limit to Lon- don, Ontario, by 1939 (Brown, 1940). Since 1939, the Forest Insect and Disease Survey, has recorded the annual distribution of the shoot moth in Ontario. The pest continued to spread to the north and east in the for- ties, reaching its current, rather static boundary, a line from the south end of Georgian Bay to just east of Lake Ontario (Fig. 1). South and west of this boundary, continuous but widely fluctuating infestations occur, whereas to the north, a few persistent isolated infestations have been reported, e.g., Ottawa, 1940; Sault Ste. Marie, 1953; and Blind River, 1938.1 4s generally conceded that the major extensions in the range of the shoot moth have resulted primarily from the transfer of infested nursery stock, which occurred on a large scale, particularly in the late forties, through extensive reforestation programs and the widespread planting of Scots pine for the Christmas tree market. These primary in- festations have become loci from which the natural dispersal of adult populations has probably occurred (Green and Pointing, 1962). Today within the pest’s range, most red pine plantations from two to 30 feet or more in height, are, or have been, infested and badly deformed; some may recover and produce merchantable trees whereas others are of no commercial value. Description of Stages The rusty-brown moths, marked with irregular bands of silver, closely resemble dried and damaged buds (Fig. 2). The female, some- what larger than the male, ranges in weight from about 11 to 50 milli- grams, and has a forewing length of 7 to 11 millimetres. It may be dis- tinguished from the male by a ring of rufous hairs surrounding the gen- ital opening, and by its swollen abdomen; the abdomen of the male is — uniformly grey, more or less cylindrical in form, and terminates in clas- pers. The egg is broadly oval in outline, approximately one millimetre in length. convex on the upper surface, flattened on the lower surface, and opaque and cream-coloured when freshly laid (Fig. 3). During embryonal development the egg darkens and resembles the orange-obrown tint of a bud scale or needle base. Immediately before eclosion the egg develops a greyish cast, which approximmates that of the needle sheath. Because of their size, changing colour, and relative scarcity, the eggs are difficult to locate in the field. The first instar is somewhat less than two millimetres long, pale yellow-brown in colour, and has a black head capsule and thor- acic shield (Fig. 4). From the second to the fifth instar, the body colour darkens but becomes lighter again in the sixth and last instar (Figs. 5, 6). The pupa, about 10 millimetres long, is yellow-brown when first formed, becoming black in the thoracic region as pupal development progresses and exhibiting a greyish cast about one day before the moth emerges (Fig. 7). The dorsal side of the abdominal segments is characterized by a double Figs. 2-7. Life history stages of Rhyacionia buoliana. 2. Adult female. 3. Eggs on needle base. 4. First instar inside needle sheath and larval web. 5. Third instar and overwintering chamber. 6. Sixth instar peceanine pupal chamber. 7. Pupa in chamber at bud base. 60 re Le _— row of spines on segments two to seven, inclusive, and a single row on the other segments. ae ; Life History and Habits Moth activity usually lasts about four weeks (Friend and West, 1933; Miller and Neiswander, 1955) beginning in Ontario as early as the first week in June during a warm season, and ending as late as the end of July during a cold one (Pointing, 1961b). Cumulative male emergence in the field precedes that of the female by several days. Most moths emerge about sunrise and remain hidden among the buds throughout the day. Shortly before or after sunset on the day of emergence, females crawl to exposed conditions where they release a scent that attracts strongly flying males, occasionally in large numbers, and frequently from consider- able distances. The following evening, mated females start depositing eggs singly or in groups of two or three on the bark of new shoots, buds, or needle sheaths, and occasionally on the flat surface of the needles. - Where new shoots are scarce, old foliage is acceptable. Although females in captivity are capable of laying more than 100 eggs, apparently fewer than one-half this number are laid in the field. As egg deposition con- tinues, the moths tend to make longer flights between successive attempts at oviposition. Under usual field conditions, eclosion occurs about two weeks after the eggs are laid. de Gryse (1932) was the first to observe the first instars wandering on the shoots and spinning silken webs between the needle sheaths and the bark on current shoots. Protected by the web, they bore into the needles, feeding on needle tissue within the sheaths. After moulting, a second web, larger than the first is spun, usually closer to the bud cluster. Early in August, after the second moult, larvae frequent- ly bore into the buds, again protected by a web, and they may destroy entire bud clusters before spending the winter inside or on buds under encrustations of crystallized resin, which accumulates in the webs. As tree growth starts in the spring, the larvae vacate the overwintering site, moult, spin new webs against developing shoots, and resume feeding. If all the buds in a cluster have been damaged, migration occurs, larvae usual- ly moving from the clusters of smaller buds on the lower branches to the bigger ones on the upper whorls, and frequently to the tree leader (Point- ing, 1962). Attack on rapidly growing shoots by migrating larvae in the late spring often results in damage to only one side of the shoot, which continues to grow and forms a crook or posthorn. Late in May, before pupation, fully-developed larvae cut circular exits in the buds from wi- thin the prepared pupal chamber; these holes are capped with a mixture of silk and resin (Pointing, 1962). About three weeks later the pupae wriggle through the chambers, burst the brittle covering and become wedged in the openings; then the moths emerge leaving the empty pupal cases pro- truding from the buds. | Ecology As the temperature rises in the spring, shoot moth larvae begin feed- ing, Drooz and Waters (1958) suggesting that several days with tem- peratures above 60°F. are required to initiate spring feeding in larvae in Pennsylvania. These conditions are generally satisfied by about the middle of April throughout much of the zone of continuous distribution (Fig. 1) in Ontario. Work now in progress in this province is designed to clarify the little known effects of temperature on larval development during this period (Green, unpublished data). Estimates of the pupal period, which generally begins in late May, range from 10 days (Green- 62 f field, 1914) to four weeks (Omerod, 1895). Laboratory and field experi- ments recently completed in Ontario (Green, unpublished data) indicate: a threshold of pupal development of approximately 10°C.; an optimum de- velopmental temperature of 30°C.; pupal development falling off at higher temperatures; and emergence of both sexes directly related to the speed of pupal development. Adult emergence in Ontario has been described in detail (Pointing, 1961b) and compared with data presented by American and European authors. Pointing (1961b) describes a diurnal emergence pattern with the peak in emergence occurring between 0400 and 0900 hr. E.S.T. This emergence pattern is not directly related to diurnal changes in temperature and humidity, but is controlled by the dark: light cycle. Not only does the typical rhythm disappear under constant light or dark- ness, but it can also be reversed by changing the light:dark cycle. (Green, - unpublished data). | With few exceptions, e.g. (Brooks and Brown, 1936), adults of the European pine shoot moth have been considered weak fliers, and their rate of dispersal has been thought to be slow (Friend and West, 1933; Benjamin et al., 1959). Investigations recently completed in Ontario, however (Pointing 1961b; Green, 1962a; Green and Pointing, 1962), have shown that the adults are relatively strong fliers. Adults usually fly during the evening under well-defined limits of overhead light intensity and air temperature. Flight begins at an overhead light intensity of approximately 1000 ft.-c., reaches a peak of about 125 ft-c., and contrary to Hamilton (1931) and Benjamin et al. (1959) ,ceases in darkness. Moths fly at temperatures above 12°C., and maximum flight activity is reached at ap- proximately 22°C. In Ontario, warm, overcast evenings associated with the presence of air masses arising in the Gulf of Mexico, the Great Basin region, or parts of the Pacific Ocean are the most favourable for flight, copulation, and oviposition. On the other hand, polar continental or Arctic air masses with clear skies and relatively low evening temperatures limit flight and reduce chances of copulation and oviposition. Flight by females is the main factor contributing to the natural dispersal of shoot moth populations, little if any population dispersal oc- curring by larvae dropping on silk and being dispersed by air currents (cf. Wellington and Henson, 1947). Under the conditions of overhead light intensity and air temperature noted above, females fly and oviposit on successive evenings. For the most part, tree to tree flights occur when the egg complement is high, but after the females have deposited some of their eggs, they fly farther and may venture beyond the borders of the plantation. Flight mill studies in the laboratory (Green, 1962a) indicate that females are capable of non-stop flights up to 4.5 miles in still air and flights to exhaustion up to eight miles. In the field, flights of oviposi- ting females are directed into the find at wind velocities below 3.5 m.p.h. across the wind at wind velocities between 3.5 and 6 m.p.h. and downwind at higher wind speeds. Release and recovery experiments with radioac- tively tagged females (Green et al., 1957; Green and Pointing, 1962) indi- cate that a substantial portion of the female population may disperse beyond the borders of a plantation. In addition, population dispersal could undoubtedly be assisted by ascending air currents and wind ac- companying convective thunderstorms in the afternoon, such storms cre- ating conditions of light intensity and air temperature conducive to flight well before the normal evening period. Under such conditions, moths may be carried much farther than the distances suggested for flights in still air. 63 \ The incubation period of the eggs has been described by different authors as from 9 to 18 days (de Gryse, 1932; Friend and West, 1933), and is obviously strongly affected by temperature. In Ontario (Green, unpublished data), laboratory experiments have shown that the optimum temperature for egg development is 30°C. Below 15°C., both developmental rate and hatching success are low. In moist air, hatching success remains above 90 per cent until temperatures beyond 30°C. are encountered, dropping rapidly to about 40 per cent at 34°C. In dry air hatching success is greatest at 17.5°C., dropping to 68 per cent at 30°C., and to less than’ 10 per cent at 34°C. Desiccation apparently reduces hatching success. Upon hatching from the egg, the first-instar larva wanders on the stem and needle sheaths until a suitable site for entry into a needle is found (de Gryse, 1932; Pointing, 1962). A wandering period of several hours has been reported (Friend and West, 1933; Miller and Neiswander, 1955) but recent investigations at Elmira, Ontario (Green, unpublished data) indicate that the wandering phase seldom exceeds one-half hour, larvae soon finding a suitable site for the constructon of the initial web — prior to entry into the needle. The speed of larval movement increases with temperature, and although the location of an entry point into a needle may be accomplished in a matter minutes after hatching, actual penetra- tion into the needle tissue requires several hours even under the most favourable conditions. On hot or dry days, newly-hatched larvae, which had begun forming the initial web by mid-morning. often ceased their establishment activities and rested in the shade of the needle sheath until conditions moderated in the evening. Then, they either completed the feeding tunnels started earlier, or moved to new sites starting the whole process over again. These delays in establishment may increase larval mor- tality through increased predation, desiccation, or other environmental stress. The northern limit of the shoot moth distribution in Ontario corres- ponds closely to a minimum winter isotherm of —20°F. (Fig. 1), which West (1936) considered as limiting on the basis of laboratory experiments with the insect in Connecticut, and which Rudolf (1951) and Benjamin et al. (1959) have employed in forecasting potential danger zones for plantations in Michigan and Wisconsi, respectively. This method of fore- casting potential danger zones on the basis of minimum winter tempera- tures has met with only limited success since little consideration was given to the insulating qualities of snow cover, or the possibility that larvae may be capable of cold-hardening (cf. Batzer and Benjamin, 1954). Therefore, when the insect became the subject of intensive investigation in Ontario (Pointing, 1961b), the problem of overwintering mortality due to low winter temperatures was re-examined (Green, 1962b). Green (1962b) found that populations occurring in different tem- perature zones in Ontario and Michigan possessed the same inherent ability to supercool, with no evidence that more cold-hardy races are evolving. On the other hand, it was found that overwintering larvae were capable of cold-hardening upon exposure to low temperatures with the overall effect that more northerly situated populations were better able to survive a given temperature within the lethal range than were those in the south. Regardless of the level of conditioning, however, no larvae were able to withstand exposure to temperatures below ca. —20°F. When the insulating qualities of snow cover were examined, it was found that the European pine shoot moth could exist with no mortality due to freez- ing anywhere within the North American distribution of red pine if snow 64 cover is sufficient to cover infested buds to a depth of eight inches when air temperatures are within the lethal range. In general, isolated occur- rences of the shoot moth in Ontario and Quebec north of the —20°F. mini- mum winter isotherm are dependent upon snow protection, which has also been instrumental in maintaining populations within the zone of continu- ous distribution during very severe winters (Béique, 1960; Pointing, 1961a; Green, 1962b). It has been suggested (Benjamin et al., 1959) that larvae surviving beneath the snow cover on the lower branches of host trees would have little effect on the form or shape of the tree the following spring because, upon resumption of activity, they do not move far, and generally enter adjacent buds on the lateral shoots. Pointing (1962), how- ever, has shown that larvae resuming activity in the spring show a strong tendency to ascend the tree and it is common to find the leading shoot in- fested by a migrating spring or summer larva. In Ontario, mortality due to freezing is one of the most important natural controls of European pine shoot moth populations, the degree of control depending upon the severity of the winter temperatures and the timing and depth of snow cover. Damage Although the European pine shoot moth attacks most pines (Neuge- bauer, 1952), some species are more susceptible than others; red pine is the most susceptible species; Scots, Austrian, and ponderosa pine are moderately susceptible; and pitch, Virginia, jack, and eastern white pine are relatively resistant (Miller and Heikkenen, 1959). Damage to individual trees caused by young larvae feeding in needles results in conspicuous browning and drooping of the needles, particularly those surrounding the buds, and occasionally in severe infestations, par- tial defoliation of the new shoots results. This damage is of little conse- quence, but destruction of the buds may cause major stem deformaties or only minor reductions in the complement of lateral branches. The latter arise when one or more lateral buds are destroyed, whereas the destruction of the terminal bud or bud cluster gives rise to the former. After the third- instar larvae destroy an entire bud cluster, up to 70 adventitious buds are Fics. 8-10. Typical summer damage by third instar. 8. Well-developed witch’s broom. 9. Top killed by repeated attacks on witch’s broom. 10. Recovery six years after single, severe witch’s broom-forming attack. 65 produced during the summer and become a witch’s broom the following spring (Fig. 8). Reinfestation of the brooms may kill the tops but if the infestation subsides, the tree may recover with little deformity (Figs. 9, 10). Damage caused by spring feeding is usually permanent. Minor crooks form when lateral branches replace dead terminals. Major crooks develop from the spring feeding of larvae on developing terminal shoots, which tilt and continue to grow, forming permanent posthorns (Figs. 11, HA tot3 ).. Damaged shoot showing early stages of posthorn development. 13. Crook seven years after initial attack. Repeated attack of the leading shoot renders the tree virtually useless as timber but still of some value as pulp or cellulose. It is possible for a tree to grow out of minor deformities after several years. However, struc- tural weaknesses at the site of the old deformity greatly increase the chances of wind shearing and breaking. Whereas the losses in value of in- dividual trees in a plantation may be high, a sufficiently large number may recover and provide an economically valuable crop. Control If we agree that ‘“‘an insect is controlled when it does not cause econ- omically intolerable damage” (Turnbull and Chant, 1961), then shoot moth control must result in the eliminat.on of virtually all larvae since one larva may seriously deform a tree by causing a crook or posthorn. Conspicuous, infested shoots on lightly-infested ornamental trees may be removed in the fall or spring but the procedure is not practicable in large plantations where timber is the final crop. However, the shearing and shaping of Scots pine Christmas trees can be done in August (Larsson, 1960) when the larvae are in the buds and this should provide better shoot moth control than would earlier pruning. The removal of the lower bran- ches of trees in plantations where temperatures of —20°F. occasionally occur, eliminates the chance of residual populations surviving beneath the snow (Pointing, 1961a). By and large, however, plantations grown for timber crops cannot be protected adequately by pruning. The combined effect of native and introduced parasites is negligible. Since 1928, over 111,000 individuals of 13 species: have been introduced. Four species, Orgilus obscurator (Nees), Temelucha interruptor (Grav.), Pimpla turionellae (L.), and Tetrastichus turionum Htg. have become established (McGugan, 1962). Of the 21 introduced and native species, which account for the circa 10 per cent parasitism of the shoot moth in 66 Ontario (Watson and Arthur, 1959), O. obscurator may account for as much as 75 per cent of the parasitism (McGugan, 1962). In Quebec, over a five-year period, 60 per cent of the larvae on Mugho pine were parasi- tized, the most important species again being O. obscurator (Béique, 1960). The biology of a number of the introduced species has been investi- gated (Juillet, 1959, 1960a, b) but an adequate explanation of their ap- parent inefficiency is yet to be obtained. An effort to assess the parasite species critically has been made (Arthur and Juillet, 1961), and further test introductions are planned, but the past introductions must be regard- ed as failures (Turnbull and Chant, 1961). Because of the cryptic habits of the larvae, chemical insecticides have not been wholly effective. Satisfactory control in nurseries has been ef- fected in the spring by methyl bromide fumigation of dormant seedlings (Flink and Brigham, 1959) and in the fall by a phosdrin dip or spray (Butcher and Haynes, 1958). Despite the recent development of numerous chlorinated hydrocarbon and organic phosphate insecticidal formulations, DDT has remained the best insecticide for plantation spraying over the past decade because of its low cost, low mammaliun toxicity, and its relatively high efficiency (Stearns, 1953; Miller and Neiswander, 1955; Butcher and Haynes, 1959, 1960). Effective control has been obtained only on experimental trees or plots where high dosages are practical. Bacillus thuringiensis Berl. is less effective against shoot moth than other lepidopterous larvae (Butcher and Haynes, 1959) possibly because the former, when boring into needles or buds, deposit chips of surface ma- terial, e.g., bud scales, bearing spores, in their webs, and ingest only the inner tissue (Pointing and Angus, unpublished data). This behaviour may influence the effectiveness of insecticides and suggests that systematic insecticides may offer a solution. Thimet, used as a soli drench, shows con- siderable promise (Butcher and Haynes, 1958), although its mammalian toxicity is high. Concluding Remarks Over the past 35 to 40 years, the European pine shoot moth has be- come firmly established as an important element of the insect fauna of southwestern Ontario, where it is likely to persist indefinitely. No effect- ive and practical means of control over its range are known, but it would be extremely pessimistic to assume that this condition will persist. In- tensive population studies now in progress in Ontario are providing us with the basic knowledge of the insect essential to the development of sil- vicultural, biological, and chemical control methods. In addition, tree breed- in experiments for resistant strains (Holst and Heimburger, 1955) are continuing with interesting possibilities. To date, the effects of predation on shoot moth populations have been little studied (Juillet, 1961) but it is . possible that investigations along this avenue will prove rewarding. As more knowledge of tree reactions and recovery from attack is obtained, methods of reclaiming severely infested plantations and stands may be developed (cf. Cline and MacAloney, 1931). Literature Cited ARTHUR, A. P. and JUILLET, J. A. (1961). 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(1933). The present status of the European pine shoot moth in southern Ontario. Rep. ent, Soc. Ont. 62: 58-61. STEARNS, L. A. (1953). The biology and control of the Nantuckett pine moth and the European pine shoot moth. J. econ. Ent. 46: 690-692. TURNBULL, A. L. and CHANT, D. A. (1961). The practice and theory of biological control of insects in Canada. Canad. J. Zool. 39: 697-758. Voutr, A. D. (1957). Regulierung der Bevolkerungsdichte von schadlichen Insekten auf geringer Hohe durch Nahrpflanze (Myelophilus piniperda L., Retinia buoliana Schiff., Diprion sertifer (Geoffr.) Z. angew. Ent. 41: 172-178. Watson, E. B. (1947). Forest Insect Survey. Can. Dep. Agr. Bi-Mon. Prog. Rep. Div. For. Biol 2. WATSON, W. Y. and A. P. ARTHUR. (1959). Parasites of the European pine shoot moth, Rhyacionia buoliana (Schiff,), in Ontario. Canad. Ent. 91: 478-484. WELLINGTON, W. G. and W. R. HENSON. (1947). Notes on the effects of physical fac- tors on the spruce budworm, Choristoneura fumiferana (Clem.). Canad. Ent. 79: 168-170. WEstT, A. S. (1985). The biology of the European pine shoot moth Rhyacionia buoli- ana, Schiffermiiller, with special reference to its relation to red pine. Ph.D. thesis, School of For., Yale Univ., New Haven Conn. West, A. S. (19386). Winter mortality of larvae of the European pine shoot moth, Rhyacionia buoliana (Schiff.), in Connecticut. Ann ent. Soc. Amer. 29: 488-448. Accepted for publication February 14, 1962 69 Ill. SUBMITTED PAPERS THE BLACK FLIES (DIPTERA: SIMULIIDAE) OF ONTARIO. PART I. ADULT IDENTIFICATION AND DISTRIBUTION WITH DESCRIPTIONS OF SIX NEW SPECIES’ D. M. DAVIES | Department of Biology, McMaster University, Hamilton, Ontario B. V. PETERSON Entomology Laboratory, Research Branch, Canada Department of Agriculture, Guelph, Ontario D. M. Woop Department of Biology, McMaster University, Hamilton, Ontario Contents ; Tn tro GuUehlOniy thee eee ee ee 71 Genus Crephia it coe eee 96 Hcl oye ys eee eons ae oieey OMe hee ie sa Mae ond? i teas a ns Genera liit se ye Pee teal al ae te GCOCENSIS, 6.00 ee ee Owiposition: 2655 bo Gane eee 74 deNOTUE. NO SPi a. a ee oT TEGO! Roe) he eka Wits htar ee Un ae eur: 74 CMET TENS 100 AEN AC te ee ee eee 74 INVENUSED {oes ee 101 pupae cone setae center acaceatatnttenentteees i MUtOtO 2 id 101 (BSG DR ia SRG SSE Ue sca degsh Sete er oreo ornithophilia Nn. SP. ...cccccccccceeees 102 Morphological Characters , ‘ Used in the Study of Adult oe Se oct ee i Black: Mlies kh ares we MN ade 77 pee ea The SD snes Sis Fe 106 Taxonomic Problems and 5 baffinense is Salita Procedure ee hug ree eee quart ae % CONGUVECNATUM oe cccs cceesecseesseee 107 Keys to the: Genera. frm eee 81 Corbis (Ae a 108 Bouts Dente e tees eee e sees ee eee eect tees einer ees eS CLOLEOND LG ee eee ae OY OEMS se Sa Ame aps selene Esra ge oad acer e COCOTUMY 2 SI Ae ee Keys'to Prosimuleinies i ye 82 EMATGINATUM. Ne SP. oo. ees 110 MemMales Gee ciceiel heen aaaeaes 82 CUTYAAMINICULUM oo ee tae MES See eens cs ie Oa ees Neer 83 EXCISUM Ne SPe oh eee J E401) OF: Ke Minne MMR ACRE een een jy ci 84 fibrinflatum 2. 114 Keys to Cnephia WATE muon com TRU Minit 84 furculatum BA Oe ee 2 ae 3 a a 115 Females 84 Goulding. i. hea ee 115 ARG CE De ans inpar nesp) | 116 Pupae POR NGPA bon aba Och ier wily 8 85 mMmNOCeENS (EDs ee eter arene eneeer eens Kays to Sumulinm 12 os eee 86 JOUNING SO o.. rs Ioet toes sea ee 118 F 1 86 latines 0k AO Ne eee ee 118 Males PSE ae aretha haute hay Wee nang 88 lonoistylatwm: 7) 2 ee ek ee ion Spa Len ty aN e ERG he hae Miron Rae ae parhaseunt 2 Hae Deets ea eterna he EL Tira tend 20 Pictipes® 0 RE ee 120 Genus Twimnig seo e, 92 PUGELENSE 7) ck a toe 121 BUD DLE Stre yik| 9 ‘| cr ) = t) 3 | Q | 3° Fic. 1. Map of Ontario showing the counties and districts 80 ples from the authors’ collections were corroborated b y cytological methods by K. Rothfels and his students who were the first to recognize many of these species complexes (Rothfels, 1956; Basrur, 1959; Dunbar, 1958, 1959). In preparation for this paper, collecting trips to many parts of Ontario were made. One of the most notable was a trip in 1961, to Big Trout Lake, in the Patricia portion of the Kenora District, a region where little col- lecting of simuliids has been done for the past one hundred years. Collec- tions of immature stages and flying adults, as well as a large series of reared adults, were made. The adult specimens were frozen dried on pins (by the method of D. M. Wocd as reported in Syme and Davies, 1958). Additional specimens were preserved in eighty per cent ethyl! alcohol. In this way, with many specimens, the extent of the variation of the morpho- logical features of existing species was determined and new species estab- lished. Included in this paper are descriptions of six species new to science, and records of several species not previously reported or confirmed from Ontario (preceded in the text by a +). Also breeding sites of other Ontario species, previously known only from net collections, are reported. In addition to the species discussed herein, the authors have collected, in small numbers, immature stages of six other species, three related to Prosimuluum fuscum and P. mixtum, one belonging tc the Cnephia sailerr Stone group, one close to C. dacotensis, and the other resembling Simulium luggert Nicholson and Mickel. We have tried to use characters in our keys which we believe will pro- vide the least difficulty to the user and yet be sufficient to distinguish the majority of the specimens of the Ontario black-fly fauna. Wherever possible, the keys have been arranged to reflect natural relationships be- tween the species. In this paper we have adopted a rather conservative view in recognizing the occurrence of only four genera in the province. We recognize certain subgenera, but refrain from their use because of the uncertain subgeneric assignment of a number of species. The distribution records of the species of Simuliidae are listed across the Province, from west to east, by counties or districts having approxi- mately the same latitude (these are delineated on the map by heavy, dark lines) (Fig. 1). They are followed by the earliest and latest dates of col- lection for each area. All drawings were made, with the aid of a microprojector, from cleared material suspended in glycerin in order to retain, as much as pos- sible, the natural shape of the specimens which can be distorted by flat- tening when permanently mounted. Keys to the Genera of Ontario Simuliidae Adults 1. Costa with fine hair only, not interspersed with spinules; radial sector distinctly forked apically; with or without a bulla behind eye laterally; calcipala absent ......... Costa usually with spinules interspersed among the fine hair; radial sector simple (occasionally obscurely forked at. extreme apical portion) ; no bulla behind eye later- iverealcipars usually DPEeESCNtMi kk tee ee cota a Weeba iean Sorrad ay 2. A bulla behind eye laterally; antenna 9-segmented; ovipositor of female short, not reaching anal lobes; dististyle of male with a single APIGAlLESPING hae ees: En eee alas apres Caen . Twinnia tibblesi Stone and Jamnback No bulla behind eye; antenna 10- or 1l-segmented (9-segmented in P. gibsoni) ; Ovipositor of female usually extending to or beyond anal lobes; dististyle of male often, with. more than one-apieal spine 0.02) Prosimulium Roubaud 3. Length of vein R not less than one-third the remaining distance to apex of wing, with hair dorsally; second basal cell of wing usually distinguishable; second hind tarsal segment without pedisculus or this represented by a shallow depression 81 Lee) OM yeh ee Coe cee SR EY RTOS 60M ERC a Ae RUD ce sltemae a en ee Cnephia Enderlein Length of vein R usually much less than one-third the remaining distance to apex of wing, with or without hair dorsally; second basal cell of wing incomplete or absent; second hind tarsal segment with a distinct, usually deep pedisculus ............................ RM Ian SCORE. peor ME aN ee tc gun se WNL a ee yee Sg Simulium Latreille Pupae . Cocoon irregular, shapeless, without a well defined anterior margin; terminal ab- dominal-segment with two lone spines) = . 3 420302 4 Cocoon usually well developed, variously shaped, usually with a well defined an- terior margin; terminal abdominal segment with two short spines or none ................ 9 . Tergites 6-8 without an anterior row of fine, spine-like hooks ..................0.0.. 3 Tergites, 6-8, at least, each with an anterior row of fine, spine-like hooks ............ A . Pupa small, 2.0-3.0 mm. in length; respiratory organ with two, short, main trunks that give rise to 15-23 (av. 19) pale, slender filaments | ............... Cnephia abdita Pupa larger, 4.0 mm. in length; respiratory organ with three, stout, longer, main trunks that give rise to 16, usually darkened, filaments... _......... Twinnia tibblesi o Respiratory filaments: Ou. eee ee eas ea Prosimulium decemarticulatum Respiratory: filaments 12 or more ..400 Se ee ee 5 « Respiratory. filaments 47 or less). eh eo ee ee 6 Respiratory: filaments 20: .or:more 20) ae eee i . Respiratory filaments 12 (rarely 14) arising from two or three main trunks ....... Re SIRS NCSU 2 OREN Aa AOS oa Se oes Chet tie vo ine ee) ee ae Cnephia Respiratory filaments 14-16 arising from three main trunks ................... Prosimulium . Respiratory filaments 22, arising from three main trunks that branch into 10, 4, 8 (dorsal, lateral, ventral) filaments respectively; most branching of filaments oc- curring at a considerable distance from base .........._......... Cnephia denaria n.sp. Respiratory filaments 23 or more, not arranged as above; most branching of fila- 8 “ments: occurring. close ‘to: base fo. 8 ee . Respiratory filaments arising from a rounded knob on a short petiole —.............. PAE een Tine ee er ee Gi er Re ee RO LIZ MIT: Sicko SIGS Respiratory filaments not arising from a rounded knob on a short petiole............ Prosimulium . Cocoon stalked, and anterior margin not well defined; or, if not so, lateral margins of terminal segment with short, curved, double or treble pronged, or single hooks eee el Mea oirpren in nee ON RN OMe SERRA TR LCs Cocoon not stalked, and anterior margin well defined; lateral margins of terminal segment without short, curved hooks although setae may be present ............ Simulium Keys to the Ontario Species of Prosimulium Females . Claws each with a large, basal, thumb-like projection (Fig. 7); apex of abdomen rounded; ovipositor flaps short, not projecting posteriorly as two slender, pointed PROCESSES hea eee ai Dig ae a Se ee 2 Claws simple or with a small, sub-basal tooth; apex of abdomen pointed; ovipositor flaps longer, projecting posteriorly as two slender, pointed processes ...................... 4 . Antenna 11-segmented; frons narrow, at narrowest part less than one-fourth as wide as long; arms of genital fork slender at base, greatly expanded from about the middle where a slender, spatulate, apically denticulate process arises on the inner margin of each (Fig. 15); hair on stem vein dark; large species (4.0 mm.) ............ wide as long; genital fork not as above; hair on stem vein pale; smaller species (25043825 nm ye OS De ak gu a 3 . Antenna 9-segmented; antenna and legs dark brown, concolorous with remainder of body; galea of maxilla reduced, with fine hair apically; anal lobe subquadrate, in- dented posteriorly; terminal plates of genital fork wrinkled, posterior margins dentate: (Mie), Si a acta soe, en eine ce cee ene Ne aU os NG A gibsoni Antenna 10-segmented; antenna and legs orangish-yellow, contrasting with dark brown body; galea of maxilla with retrorse teeth; anal lobe broadly L-shaped; ter- minal plates of genital fork not wrinkled or dentate ..... .................. decemarticulatum . Anteroventral margin of anal lobe evenly rounded, without a distinct anterior pro- jection or “heel”, so that anterior margin is straight and anal lobe is broadly L- shaped, posteroventral margin extending noticeably beyond posterior margin of cercus; ovipositor flaps relatively long and slender, reaching tips of anal lobes ..... Antroventral margin of anal lobe with a distinct anterior projection or “heel” so that anal lobe is boot-shaped, postroventral margin reaching but not extending beyond posterior margin of cercus; ovipositor flaps relatively short and broad, BeaeRye FeGeninyg (tips Ol alia! “lOpese sec tone te swe Se i cas A 6 . Sensory vesicle of third palpal segment opening to the exterior by means of an enlarged, elliptical mouth, the connecting tube very short and indistinct or absent; median space of buccopharyngeal apparatus deep, broad and squared; mandible with forty or more serrations; claws viewed from the side, strongly curved, curving from the base so they often appear nearly semi-circular 2.0.0.0... magnum Sensory vesicle of third palpal segment opening to the exterior by means of a smaller, circular mouth, with a short but distinct connecting tube; median space of buccopharyngeal apparatus shallow, narrowly U-shaped; mandible with thirty- eight or less serrations; claws viewed from the side straighter, with a slighter degree of curvature, greatest ‘curvature near tip, the curving beginning at about one-half er RCPS RLM Sot en aa enon ie Ney cane, SE ee un at abr) aa multidentatum . Sensory vesicle of third palpal segment opening directly to the exterior by means of a wide mouth, the connecting tube very short or absent; two basal segments of an- tenna orangish-brown, contrastingly lighter than segments of flagellum, antennal hair all black; humeral angles of thorax lighter than scutum; thoracic pilosity gol- den; ovipositor flaps broadly rounded along entire outside margins, sclerotization PpRRPRIS EM ONO MNS. ALLOW 1 ccs ek ed oat eS Bar eae MORE a Pa) fontanum Sensory vesicle of third palpal segment opening to the exterior by a conspicuous tube which does not expand to form a wide mouth; two basal segments of antenna concolorous or only slightly lighter than segments of flagellum, fine antennal hair pale yellow to white, coarse hair black; humeral angles of thorax usually not lighter than scutum; thoracic pilosity yellow; ovipositor flaps not broadly rounded along entire outside margins but distinctly tapering apically; sclerotization of inner mar- SELLS PRESET GS eee ge era ae ee ie a I A ee ae en a Ney Core it . Selerotization pattern along inner margins of ovipositor flaps broadly expanding laterally into a shoulder at the proximal end of each flap, inner margins of flaps not conspicuously concave basally; median space of buccopharyngeal apparatus SIDS STS E ENG OPS a SCS ge le Ma eM tcl ne a i _ fuscum Sclerotization pattern along inner margins of ovipositor flaps narrow, not expand- ing into a lateral shoulder at the proximal end of each flap, inner margins of flaps: conspicuously concave basally; median “space of buccopharyngeal apparatus shal- Pamnacmrrenvwhy eG) Or VoSiha Ped es ce eS Ss ee ede oe ead sate eee miatum Males . Antenna 9- or 10-segmented; dististyle with a single apical spine .............0........ 2 Antenna 11-segmented; number of apical spines on dististyle variable ......... .... 3 . Antenna 9-segmented; setae on basistyle concentrated mostly on distal margin; dististyle, in lateral view, rounded apically; ventral plate, in ventral view, spatula- shaped, rounded apically, basal arms moderately long, slender, bluntly pointed; me- dian sclerite narrow, heavily sclerotized, pointed apically (Fig. 56) 0.0.0.0... mn ee sk Se I MS Ee re I i cle ena eS Cte gibsoni Antenna 10-segmented; setae on basistyle more numerous and generally distributed, not noticeably concentrated on distal margin; dististyle, in lateral view, conspicuously ~ pointed; ventral plate with conspicuous, median notch on apical margin, basal arms short, sharply pointed; median sclerite long, narrow, heavily sclerotized, with only minute apical arms so that it appears almoss square at apex (Fig. 55) eR SP Se KE i RUE A a ee CS Aare ae waul Teas dls oe feedesos feat decemarticulatum . Apex of dististyle pointed, with a single terminal spine; ventral plate with a long, median, basal process, apical margin with a median notch, basal arms short, pointed; median sclerite trough-like, bearing two small prongs apicolaterally (Fig. 57) ec SET REESE ay CES eas AU eI a La 0 Re eel ee ea Oe _ wvernale Apex of dististyle obliquely rounded or truncate, with 2 or more apical spines; wenuth plate and: median, SClerite Not as’ above... 22.) ei A . First flagellar segment of antenna conspicuously longer than pedicel; basal fringe of abdominal scale dark basally and pale apically; ventral plate, viewed ventrally, long, broad, conical in outline, bluntly pointed apically; dististyle conspicuously triangular BHPCEL ENC WIER oe PICA USDINGSs Scent eA Sn See yee Fe) clk aie ac 5 First flagellar segment of antenna about equal to, or only slightly longer than pedicel; basal fringe or abdominal scale entirely dark; ventral plate, viewed ven- trally, much shorter, thinner, and usually more sharply pointed apically; dististyle not as conspicuously triangular in outline, with 2-3 apical spines ...........000000000000...... 6 . First abdominal sternite triangular in shape, rounded poster 1Ony dististyle with 4-5 SEPM Ce Ue SENTING 8 a0: fare a trey vara ui seas Soto evsghe hokoan ap See sthine ine sesae Sea ck ey multidentatum First abdominal sternite trapezoidal in shape, with a straight hind margin; disti- style with 2:3;‘rarely 4, apical ‘spines; = 4 a ee a ee magnum . Sensory vesicle of third palpal segment without, or with only a very short tube connecting it to the exterior; pleural membrane usually sandy coloured; first abdom- inal sternite trapezoidal in shape, with a straight hind margin; ventral plate, viewed ventrally, long, slender, and acutely rounded apically .0.0000.000...0.0..0000..0.... fontanum Sensory vesicle of third palpal segment with a distinct tube connecting it to the exterior; pleural membrane light brown to dark brown; first abdominal sternite | trapezoidal or triangular in shape; ventral plate, viewed ventrally, either short, relatively broad, and bluntly pointed, or long, narrow and sharply pointed apically me . First abdominal sternite triangular in shape, broadly rounded posteriorly; ventral plate, viewed ventrally, short, relatively broad, and bluntly rounded apically ............ Te a CEE No ei el RUE BS a pes BI asc ace a ca eee er fuscum First abdominal sternite trapezoidal in shape, with a straight hind margin; ventral plate, viewed ventrally, long, narrow, and sharply pointed apically 0... 0... uBR pu Ve ope gaceicibs Gal seal EERIE Chay Oe) Re coe Ot Re Neat claire) ee Mim «Len ee ee ee miaxtum Pupae . Respiratory filaments 9, nearly as long as pupa ........ 0... decemarticulatum Respiratory filaments more than 9, and generally shorter ©... uae eee 2: . Respiratory filaments 14, their bases thickened and divaricate, rather abruptly taperine. to: long; Fine branches i ae. ee gibsoni Respiratory filaments 16 or more, their bases may be divaricate but filaments more’ evenly ‘tapering oe as he ek ge og ee ee 3 5. RESPITALOT YA LAMENESS IG Fe: fn hae Rak oc a eeeete ales alr ats ia Pc eee Oe ee eh A Respiratory. filaments about: 23-30...0 ee 5 . Abdominal sternites 3 and 8 each with two small hooks on posterior margin (the hooks of sternite 8 sometimes absent) ; the dorsal primary trunk of the respiratory organ divides into an inner branch with five filaments and an outer branch with three filaments; filaments of the other two primary trunks not generally occurring in pairs but are given off singly at regular intervals from the base of each eae piietrct eee een aed tenn ae eee Ce IN aie NCR Ut MAAR NCE ge ONE eR MEME te io vernale Abdominal sternites 3 and 8 bare, at most with scattered setae; the dorsal primary ~ trunk of the respiratory organ divides into an inner branch with three filaments and an outer branch with five filaments; filaments of the other two primary trunks generally arranged im: pairs 0. 22. ee Ree i ee eee fontanum fuscum mixtum . Respiratory filaments short, entire clump of filaments, viewed laterally, as wide or wider than long, rather densely clumped, arising in three distinct groups, brown- ish in colour; spine-like setae on tergite 2 and those on lateral regions of segments 2-4, coarse, dark, more numerous; spine-like hooks on anterior margins of tergites 5-9 coarse and dark; spine-like setae on sternite 3 coarse and dark; large species (5:5=6.0> Ms) oe ee ee EE ec Chae Ng magnum Respiratory filaments longer, entire clump of filaments, viewed laterally, distinctly longer than wide, less densely clumped, arising in two main groups, the anteroventral group with the fewer filaments, pale yellow in colour; spine- -like setae on tergite 2 and those on lateral regions of segments 2-4, finer, more pale and less numerous; spine-like hooks on anterior margins of tergites 5-9 finer and more pale; spine-like setae of sternite 3 finer and more pale; smaller species (5.0 mm.) ...... multidentatum Keys to the Ontario Species of Cnephia Females » Claws simple 0020 ek ee ee i ee Se Sec) 6 een ee oe Claws each with a small, sub-basal tooth or a large, basal, thumb-like Brian CRI OTD oi SONS ce ee BA SO er ey ah ON en) ee . Galea of maxilla with retrorse teeth, mandible serrate; calcipala large and broadly FOUNGEO 50 AT ie oe Ee ORG ie aman eA Ane tee mutata Galea of maxilla without retorse teeth; mandible not serrate: calcipala shorter and Somewhatipormbed i). Me ay Rae a a eae eee eee ee ee ee rh a emergens . Antenna 10-segmented; claws each with a large, basal, thumb-like projection and a shorter basal projection so that claw appears trifid; precoxal bridge complete, slender Di AUR pee Red A NAMA Re ANC oN Wits PERL EC ME REDS 5 a EN GTM a a NRCS OMG LS Uh ko denaria Nn.sp. Antenna 11-segmented; claws each with a small, sub-basal tooth or a large, basal, thumb-like projection; pre-coxal bridge variable ...,. sibs) a 1 SS ee A 84 — . Ninth tergite produced posteriorly, snout-like (Fig. 24); sternites 2-7 sclerotized; claws long, slender, each with a small, sub-basal tooth; frons wide; precoxal bridge POMC EON TS IOTIORE! (ate esa ah ar hs hala ia Ree ee ae Oe EN eee TN cde | dacotensis Ninth tergite normal, not produced snout-like; sternites 2-7 membranous, not sclerotized; claws shorter, each with a strong, basal, thumb-like projection; frons aeubta Ble 7) PECCOMA lh DIIO@e Variable, 90... Sas ee) oe eta sae 5 . Anterior wing veins with fine hair only, not interspersed with well-developed spi- nules; frons moderately broad; sensory vesicle of third palpal segment small, glob- ular, about one-fifth as long as the segment; precoxal bridge complete, slender; small species (2.0-3.0 d99 0195) aN eee tine gh ee Demian ie aa na SP JL pte he Ae oe ee abdita Anterior wing veins with well-developed spinules interspersed among the fine hair; frons narrow; sensory vesicle of third palpal segment larger, elongate 2, at least one- third as long as the segment; precoxal bridge absent; large species, over 4.0 mm pe ne Oe ngs re ee re ele ha Roe ela hy at We ea ria co Rey oR Tu be ae, 6 . Body, legs and antenna dark grayish-black to black; neck of sensory vesicle, arising from the distal tip of vesicle, of nearly uniform width, not expanding to form an enlarged opening to the exterior; arms of genital fork short, abruptly ex- panding distally into large, irregular, triangular to square, strongly sclerotized CES RS DEN a) Se TOR Ec eater weep Vi a dace ga Mi a oe invenusta Body and antenna dark brown, legs yellowish-brown to orangish-brown; neck of sensory vesicle arising near middle of vesicle, expanding distally to form an enlarged opening to the exterior; arms of genital fork longer, expanding into lightly sclero- tized, L-shaped plates, each with a strongly sclerotized, narrow ridge on internal SieceraRRECEEO UN. «COREE: 2a) (ok a OM eee ee el vad S ornithophilia n.sp. Males* . Antenna 10-segmented; dististyle, at about distal one-third of its length, abruptly tapering into a long, slender point with a single apical spine .............. denaria n.sp. Antenna 11-segmented; dististyle variable, if pointed apically not abruptly tapering from distal one-third into a long, slender point; number of apical spines variable oe ee Ne es ee IE eg ES OR ee ee a Pees. win one Cermimial. Spine =2..6. fl... 2 ee ee ee dacotensis 3 Pirsnicayler with: voor LORMEMal SPmnes = 29) ao kits ' iL R ie a ee yal . Anterior wing veins with fine hair. only, not interspersed with well-developed spin- pateee BLE ISPCCICS C20 ITY a eee agg riety Sige Pnee Bice eer este abdita Anterior wing veins with well-developed spinules interspersed among the fine hair; SUE SUES. AUEEA SLT VST OS ae eee cs a ad ae me Se eee ee ean ee evn Oo a eee 4 . Dististyle tapering toward apex, slightly curved, apex laterally compressed; ventral plate with a rather long, ventral lip (Fig. 58) ; ‘calcipala minute; large species (4.0 SERED Te Ee er TE Nera ach ol ae ek ame RE ae Oe mvenusta Dististyle nearly parallel-sided to near the apex, not curved, apex not laterally compressed; ventral plate with a short, ventral lip (Figs. 61, 62); calcipala larger; eC LCS Ce) ORIN errr cis ea fede enh Noe feu SST Te Ge Sakueg es 5 . Galea of maxilla of normal size, nearly as long as labrum-epipharynx ........................ . Respiratory filaments 12 or less. ................... ORE REARS COR ea ee earn Sah ec: 2 Pe IEAOEy PTamMeitse Ho sOFccIMOne (oi Os ged ot ke RL ee 4 . Respiratory filaments 8, short, stout, all arising from the base and curving toward a common point; cocoon with a definite shape, situated upon a stalk os. ee Fe ah ie, EE A et Be Ra ae OBO ANE lar A aA Pag eo aha an a OO WOE SEE Respiratory filaments 12, long, slender, not curving toward a common point; cocoon irresular, shapeless; not situated upon a ‘stalk~ .....2).22 0k. 3 . Respiratory filaments arising from three main trunks of 4, 3 and 5 filaments re- spectively (dorsal, lateral, VEMERAI SOR ve ere eg | he nes yen Geen ete et Oe emergens Respiratory filaments arising from two main trunks which diverge from each other, the ventral trunk with 5 filaments, the dorsal trunk dividing into two branches Wn fos canes 7 el aMenas. FES pecbively .0) ee we RE ee mutata . Tergites without strong hooks, tergites 6-8 without an anterior row of fine, spine- like hooks; respiratory organ with two short, main trunks that give rise to a total ier tye bo) tle Slen@ers aMmentse: | snot) ie es ek ca as Wise ene abdita 2The male of C. ornithophilia n.sp. is not known. 8The pupa of C. ornithophilia n.sp. is not known. 85 10. Sai Tergites with some strong hooks, and, at least, tergites 6-8 with an anterior row of fine, spine-like hooks; respiratory organ with about 22-40 filaments arising in three..or more Main™ @roups! os. ek ee es ee 5 . Respiratory filaments 22, arising from three main trunks that branch into 10, 4, 8 (dorsal, lateral, ventral) filaments respectively 000... denaria n.sp. Respiratory filaments 30-40, arising in six or seven main groups that in turn arise from a- short, bulbous base 2255 ee ee eae dacotensis — Keys to the Ontario Species of Simulium Females Vein: Rwith, hair-dorsallyes os a ee pntvhads eee; nn bee 2 Vein R without hair dorsally: 2.05.2 ee eee eee 18 = Claws sunple. 5 10 ae ot ee ee ee ey ree 3 Claws each with a large, thumb-like basal projection (Fig. 7) ...............22.000cceeeeeseeeeess A . Mandible serrate; galea of maxilla with retorse teeth ..........0...0 0... furculatum Mandible and galea of maxilla reduced, with only fine hair apically ... baffinense . Basal two-thirds of tibiae (integument and vestiture) yellow, contrasting with the distal black portion (integument and vestiture); postscutellum with two patches of gold hair (usually 20 or more hairs in each patch) ......0..0..0000c aureum* Tibiae not as above, the integument darker basally as well as distally, these dark areas usually connected by a dark strip along the dorsal edge (in teneral specimens), or tibiae brown, gray or black (in rivuli and some specimens of con- gareenarum, the tibiae may be rather pale basally, but the vestiture is entirely pale); postscutellum bare (about 10 or fewer hairs rarely present in latipes) .... . Pedisulecus long and shallow, its depth less than one-third the width of the seg- ment (Fig. 7a); sensory vesicle of third palpal segment small (Fig. 3b), about one-fourth the length of the segment; second segment of antenna longer and wi- der*than. third serment<. 32 icin at ee 6 Pedisculus short and deep (Fig. 7b), its depth usually one-half or more the width of the segment; sensory vesicle of third palpal segment large, over one-half the length of the segment (Fig. 3a) (except in gouldingi, which has an extensive patch of hair on the katepisternum); second segment of antenna shorter than third. segoment> 2s a es eel ee 10 . Frons narrow, at its narrowest point about one-tenth or less the width of the head RPh ene are hee RTE ey let dereah er Meee Dene Ree Ee anda irk Re Cd eM innocens . Integument of fore coxa (at least distal half) and basal seven-eighths of femur yellow, contrasting with the adjacent gray of the thorax ...........00.0 ee 8 Integument of fore coxa gray, not contrasting with the adjacent thorax; integu- ment of femur gray or brown: and gray 02). ee ee 9 . Length of claw about two-thirds the length of the last tarsal segment; antenna gray; terminal plates of genital fork lacking well-defined, strongly sclerotized areas (Fig. 31); frons usually with concave margins .2...0..0..000c ccc rivult Length of claw about one-half or less the length of the last tarsal segment; basal two segments of antenna usually paler, contrasting with the flagellum; ter- minal plates of genital fork strongly sclerotized along the anterior edges (Fig. 28) ; frons widening above, with straight margins .................... congareenarum* (in part) . Head relatively small, its width to that of the thorax (at the humeral angles) 1 to 1.2; terminal plates of genital fork strongly sclerotized along their anterior margins; cercus longer than wide ........... CSP heme, Be Sa Se congareenarum* (in part) Head width to that of thorax 1 to 1.1; terminal plates of genital fork strongly sclerotized along their posterior margins (Fig. 29); cercus wider than long ............ se ME aa 0oe 8 We ee ae ov a ac ca oa VE er oa ey oe excisum N.sp. Katepisternum with a patch of hair along the dorsal margin (sockets of these hairs visible in rubbed specimens after clearing) ..2......0....40- 11 Katepistrenum bare '.2).s5.5. 55 ee ed Se 12 Sensory vesicle of third palpal segment over one-half the length of the segment; patch of hair on katepisternum small, centrally placed (usually with 20 or fewer hairs) ; abdomen densely covered with silvery hair, in places obscuring the inte- mument: latevalhy':0 0 oo ee eee, Ge a al Rie en aa ee croxtoni Sensory vesicle of third palpal segment about one-third or less the length of the segment; patch of hair on katepisternum more extensive, extending to the anterior margin; abdomen sparsely covered with golden hair ........0...........0. gouldingt 86 12. 13. 14. 15. 16. JOT 18. Igy 20. 21. Precoxal bridge not complete, with a narrow interruption near proepisternum (Fig. 6a) (rarely with a tenuous connection on one or both sides in old specimens (Fig. 6b)); the silvery or white hair of abdomen dense laterally, obscuring the integument, but absent on the black, dorsolateral areas of segments three and -TEGHUTTOPC Oa EGOR a RAN ie Moe agai lee samen tn aayne Nal) Sieh Al A a tag cla (Cy a ac RENO ILO 13 Precoxal bridge complete, strongly sclerotized, narrow (Fig. 6c); hair of abdomen yellow, sparse, not obscuring the integument, dorsolateral areas of segments fhmeesand four mov usually, contrastinely black and) bare .4)..5. ae. 14 Small species; width of thorax at humeral angles less than 0.9 mm. (0.8 + 0.07) ; posteromedial areas of terminal plates of genital fork strongly sclerotized, as dark as the eighth sternite; hair on scutum with a brassy tinge (similar to quebescense) when viewed under blue-filtered light; hair on stem vein black, or with some white ati Ute not sentinely. whiten ws oe Rie. Brot alee aie ua al emarginatum N.sp. Large species; width of thorax at humeral angles 0.9 mm. or more (1.0+0.1) ; posteromedial areas of terminal plates of genital fork weakly sclerotized, con- trasting with the strongly sclerotized anteromedial angles and lighter than the eighth sternite; hair on scutum white or silvery when viewed under blue-filtered light; hair on stem vein white, or white mixed with black hairs, but rarely all pee eee cee yy Marat, ee Ucn ers Ne nS Pe RE ae ber oe NOL euryadminiculum Posterolateral areas of terminal plates of genital fork, at points of attachment to ninth tergite, widened dorsoventrally to form strongly sclerotized, paddle-shaped structures which are most conspicuous in a terminal or lateral view (Fig. 39); scu- tum with pale brassy hair; a small, common species _................0..0.:::..55. quebecense Posterolateral areas of terminal plates not widened appreciably, not paddle- Shepecdemiale On SCUCUIM “Varia ples:

sparse; median hair of anal lobe produced anteriorly to about twice horizontal length’ of: cereus) 0.202254 eel ABS fos eo oe SR ee ee 28 . Inner margin of ovipositor flaps straight and slightly diverging distally; anterior margin of anal lobe not noticeably more sclerotized than rest of lobe ....................... “pe Sa ea Naas eee Be gs ah BIS Y Dun PS emcee ORO TO ee eRe Re venustum Inner margin of ovipositor lobes concave, with an oval space between them; an- terior margin of anal lobe noticeably more sclerotized than rest of lobe ....... fit ca Fae Be hawt Aas tae a pas he tp tee Ais Me SER Cc es cate a Se ae ne verecundum Anterior projection of anal lobe notched to produce two small rounded lobes; arms of genital fork tapering beyond tooth; hair of stem vein all black; hind femur black only on apieal one-fourth <=)..:-3 =. a eee fibrinflatum Anterior projection of anal lobe coming to a single acute angle; arms of genital fork with apices rounded beyond tooth; hair on stem vein variable in colour; hind femur. black -on-apical ‘three-fourth)<.2 a ee eee jenningsi Males - Vein R with*hair dorsally 2.)< 2.2)... ee ee ee 2 Vein. R ‘without hair ) dorsally <::3-. 30. 22 ee ee 17 . Ventral plate a laterally compressed, median keel that is more than twice as long as broad, basal arms extending laterally (Fig. 79); postscutellum with two patches of gold hair er ne PME MIN oe penis eo PE ca alec rit & Dowie eiage Gen ule ethan eee .. aureum* Ventral plate flattened dorsoventrally, about as broad as long, basal arms sub- parallel, extending anteriorly; postscutellum bare ......................1...cseeeetet ee 3 . Dististyle tapering to a pointed apex. with a small, apical spine (Figs. 64-70, 5) Dististyle not pointed apically but with a flattened, triangular flange eae the small, apical spine directed anteromedially (Fig. 1). ee 11 . Dististyle with a flattened, flange-like structure along the lateral edge, near the mid-point, 24 Fiat: 75) 4 ee ee a PS a ey furculatum Dististyle tapering uniformly, without a flange- like structure along the eater: COPE 52 on ek Re ee rn eee . Body of ventral plate somewhat rectangular in shape, its greatest width ee distal to the point of attachment of. the basal arms’... 2...2..5: 2]. 222 ee 6 Body of ventral plate triangular to somewhat trapezoidal in shape, its ee width being at the point of attachment of the basal arms, narrowing distally to the prominent, ventrally recurved lip (figs. 67-70); 442.23 oS eee 8 . Ventral plate, in terminal view, broadly V-shaped (Fig. 66) ; paramere narrow, strap- bike. four or more times as long as wide, the large terminal spine separated 88 10. ee 12. 13. 14. 15. 16. - between their tips greater than the width of the body of the ventral plate (Fig. WT, 18. 19. REOUbeity Wyycr MEMDTANOUS AREA okies ipl Te aetteled sg tsa baffinense Ventral plate, in termina! view, flattened; paramere rectangular, about one-half as wide as long, with terminal spine attached aS eur aga. CSS iti a Nala Ia eae Vege 7 . Distal margin of ventral plate straight (Fig. 65) 9.0.0. euryadminiculum Distal margin of ventral plate broadly concave (Fig. 64) _........ emarginatum n.sp. . Teeth on parameral arm small, the longest teeth equal to less than one-half the distance from the tip of the basal arm of the ventral plate to the point of attach- ment of the paramere; basal arms usually moderately curved medially (Fig. 68) ; scutum entirely brownish- -gray pollinose, hair brown ... ..............0.00..... excisum N.sp. Teeth on parameral arm large, the longest teeth equal to three- quarters or more of the distance from the tip of the basal arm to the point of attachment of the paramere; basal arms usually parallel or diverging (Fig. 67); central area of seutum a dark, dull brown to black (often ob:cured by hair), contrasting with the lighter pollinose marginal areas, hair yellow to brown ..00....0000......0.0000 0c ccccee eevee. 9 . Hair on scutum entirely gold; pleural tuft pale; abdominal hair, especially basal BEIM e aWiihy pale: UIPS on cg iy ae OV ea ie (ee Ne oe ee .. congareenarum* Hair on scutum entirely brown, or brown centrally with gold hair on the antero- lateral areas; pleural tuft and abdominal hair entirely (brow 4505. a2. 42 enna) Pollinosity, . slender, tightly woven: so) ssu es Op es lr latipes* One pair of respiratory filaments petiolate, the other two filaments sessile or nearly so; the anterodorsal projection of cocoon shorter, broad and loosely woven except at 2X0 Fog: \ Nese gh Re MA CMM MRI I MUO Pap Mi Mee N Lita ae i rivuli - Respiratory’ filaments (6:25) 5 2 ee a a 6 Respiratory filaments "8 or “more <2) 2 Ge 0 fi . Anterodorsal projection of cocoon long, slender, tightly woven. ............ excisum N.sp. Anterodorsal projection of cocoon shorter, broad, loosely woven ................ gouldingi 90 7. Respiratory filaments 8; anterodorsal projection of cocoon short ....... - eroxtoni Respiratory filaments 10 or 12; anterodorsal projection of cocoon very long ...... 8 SEER CSpIPALOny, bilaments sO) esaick aie co ees ets ae a na on cleric imnocens RESpPILACOLVetuamentsed 2. ccc ese eNO a Aen ae congareenarum* 9. Cocoon boot-shaped; respiratory filaments 9 or 10 .....00000.0.00000 00 . Sn isl ee as 10 Cocoon slipper-shaped; number of respiratory filaments variable .........00000.......... 12 10. Respiratory filaments 10; cocoon tightly woven, sides of anterior opening with long, cross-woven loops like a fancy wicker Basket uh eee Ie corbis Respiratory filaments 9; cocoon loosely woven, anterior end high, opening large, MEO LONG CROSS-WOVEN LOODS) as isc ee et ects ke) RRR BNE Eo Slr ai ae ill 11. Respiratory filaments, at most, only slightly swollen basally, rather short in rela- PMOMREOELOLa eNO cN. Ole PUR acti hoe ieee Lek ere aa on ela aaa Un Meche. okt pictipes Respiratory filaments more swollen basally, the swelling being noticeable especially in the filaments arising near the ventral side; filaments longer in relation to total "ETAT Ge COVE SONU CEN SOP Eee se ced lane On cd RSE meta Tce Me EP RSs erie AVN longistylatum Pe TeSMUEALOLVe tilaiments. Aa csk oh ee ee eo ite i Gel toi ea em ecule yy INE 113% PCCM ALO Gy etllAMeMUS, Gi OT, MIO OPI: race Boh hd ee ee ees Aeneas sas chd uch nce htes a aR 17 13. Dorsal respiratory filament strongly divergent at base from the other three; dor- sal pair of filaments on a short petiole, the ventral pair with almost no petiole RII een re re i Tale COU Ae eS ae hehe enn neice 2 canta > ee Shbhe aureum* Dorsal respiratory filament not strongly divergent at base from the other three; mimes: line EWO- peuolate palrs. 6225 aN a ee aa Als eandh Sagsdee so de ks Cue ne 14 14. Annuli along basal portion of respiratory filaments, just beyond petiole, numerous and narrow, giving a gray, roughened appearance; ‘ventral filaments with 5-6 an- ene Came LET cols, telleyMMeniby 26g. ee 2 eae Ih ar ERE ON aon yt 15 Annuli along basal portion of respiratory filaments, just beyond petiole, less nu- merous and wider, giving a shiny appearance; ventral filaments with 2-3. annuli MemGloMmeberror tllamenb , ves ee ee es emarginatum n.sp. euryadminiculum 15. Petiole of ventral pair of respiratory filaments at least 4-7 times as long as petiole GmeeOuSals Palm, ote MUlAMeNbS, (oi hi ee Ake i Nl es Tn umpar N.Sp. Petiole of ventral pair of respiratory filaments at mest twice as long as petiole Onsale Ol tl IRIMNGMES) ose os en eee ee oe RGAE col lpn a ee or 16 16. Respiratory filaments diverging dorsoventrally, petiole of dorsal pair at most one and one-half times as thick as petiole of ventral pair; tubercles on head and thorax sina rerularly spaced, not:‘strongly grouped... et. quebecense Respiratory filaments not diverging, subparallel, petiole of dorsal pair twice as thick as petiole of ventral pair; tubercles on head and thorax larger, placed in BIR CIN Meh Fee VOUS I os ee ee es en EG A ae Tae SE oa Poca aestivum n.sp. pugetense 17. Sides of anterior opening of cocoon with built-up walls, each having 1-3 large windows, the tops of the walls straight or evenly curved; respiratory filaments ROM iomm oem te ee ee srt Cake A cee ies RN, hag Sei Tra yee ie Sa Bids Soe AR 18 Sides of anterior opening of cocoon simple, circular, without windows; number of MesMiGAvOny —EllaMmenes Variable oo i Meo feet pee tute come none cae eet: 19 18. Respiratory filaments 6, swollen, finger-like ................ PO Gcee lbw tevin it, fibrinflatum Respiratory filaments £0, normal, not swollen...) keen ee jenningsi MECC SECO ny oP aIMeNtG xO 4100 oer ees eee Nee en iN bo eek i Oo 20 es pimaLOnVye tllAmentse S. Ol. MOGE ee. iy ye cee Wee he are re atl ee ALR CPR oe ae 21 20. Dorsum of head and thorax with pronounced reticulate rugosity .............. parnassum Dorsam of headvand thorax smooth: 2.45 ae ei eee eee Ne tuberosum* venustum verecundum PePerLeSpInatOby, mlbAIMeNts: S2: Ue Ver (ee Nee ee tt ge Te A, ei Hees pina voye MellamenGsy LANG) neces ee us ices te See ls AES these vittatum 22. Cocoon tightly woven, with thickened anterior rim or a slight mid-dorsal protrusion on anterior rim; respiratory filaments arising from 3 main trunks, branching 2, Dou GOrsal smedialyavemtral) \. e.ccc0: Ae eels cet Te Pe PN yl ae UR furculatum Cocoon, especially anteriorly, very loosely woven; without a thickened anterior rim or mid-dorsal protrusion; respiratory filaments with different branching pattern 1 Scud SES be pst age ges ae UE AEA gn aR OSU rc i eee neo DC aR ge Sees Aa RR ge De 23. Respiratory filaments thickened, in three, short, petiolate pairs, plus two singly ene ee A neat snk, Pace Na Renee inte a Corea ad ed eae eB ubes at cis Te lal decorum Respiratory filaments thin, in four petiolate pairs ......00.)0002..).cGoh ec rugglesi 1 Genus TWINNIA Stone and Jamnback Twinnia tibblesi Stone and Jamnback Twinnia tibblest Stone and Jamnback, 1955, Bull. N.Y. State Mus. 349; 19-21, Plate 5, Fig. 17; Plate 9, Fig. 33; Plate 13; Fic. 55; Plate 19) mice 76, 79; Plate 20, Fig. 81; Plate 21, Fig. 89; Plate 22, Fig. 98; Plate 23, Fig. 115 (female, male, pupa, larva). Holotype. Female, Type No. 6525, Canadian National Collection. Type Locality. Goose Bay, Labrador, August 30, 1950 (J. J. Tibbles). Ontario distribution’. Nipissing Dist., May 23-June 15. Biological notes The overwintering eggs of this univoltine species are found in small numbers scattered randomly on the bottom of cold, spring-fed streams in birch - maple woods. In Algonquin Park, the only locality in Ontario where this species has been collected, the larvae hatch in mid-April at temperatures just above freezing, and they graze in the organic silt of streams with temperatures below 50°F. Stone and Jamnback (1955) reported collecting larvae in New York State, as early as April 8. The immature stages have been found in close association with those of Cnephia abdita, while the immatures of Prosimulium decemarticulatum, Simulium latipes and S. rwuli usually occurred more than 20 feet from the spring source of the same stream. Pupation begins at the end of May and the pupae usually are almost completely enclosed in a thick bag of silk on the underside of leaves or pieces of wood. Adults presumably mate and oviposit a few hours after emergence, always remaining close to the stream. Females have reduced mouthparts and they possess a few, large, mature eggs at the time of emergence. Genus PROSIMULIUM Roubaud Prosimulium decemarticulatum (Twinn) Simulium (Prosimulium) decemarticulatum Twinn, 1936, Gael ae Res., D, 14: 110, 112, Fig. 1D, 1-3 (female, male, pupa). Holotype. Female, Type No. 4122, Canadian National Collection. Type locality. Small stream near Carleton Place, Ontario, emerged from pupa May 10, 1985 (C. R. Twinn). Ontario distribution. Kenora Dist. (Patricia Subdist.), June 21; Cochrane Dist., June 29; Nipissing Dist., May 10-July 1; Renfrew Co., May 3; Muskoka Dist., May 10-20; Frontenac Co., May 6; Lanark Co., May 8-10; Carleton Co., April 15-June 17. Biological notes The oviposition behaviour of this species has not been observed but the authors suspect that the females dispense their eggs by tapping their ab- domens to the water surface while in flight. Oviposition of this univoltine species probably occurs in mid- to late June in Algonquin Park, and the overwintering eggs appear to hatch in early spring. Larvae reach ‘maturity in southern and central Ontario in early to mid-May at a water temperature of about 50°F (authors’ data; Twinn, 1936), but not until mid-June in northern Ontario (i.e., Big Trout Lake). Larvae occur mainly in small streams, averaging 2-4 feet in width, and are often found in association with P. gibsoni, Simulium rivuli, S. excisum n.sp., S. congareenarum (sensu 4The dates included in the distribution refer only to pupae and adults. 92 lato) and S. latipes. The females have well-developed piercing mouthparts and bifid claws. They feed on the blood of birds from May 20 to mid- June, but mostly in trees at a height of 5-20 feet above the ground (Ben- nett, 1960). Prosimulium fontanum Syme and Davies Prosimulium fontanum Syme and Davies, 1958, Canad. Ent. 90: 708, 710-711, Figs. 7, 9a-b, 10a-b, 13, 16, 18-19, 23 (female, male, pupa, larva). Holotype. Female, Type No. 6984, Canadian National Collection. Type Locality. First small stream on the Tote Road on the east side of Lake Sasajewun, a mile from the Wildlife Research Station, Algonquin Park, Ontario. Pupa collected June 22; adult emerged June 26, 1956 (P.D. Syme and D. M. Davies). Ontario distribution. Thunder Bay Dist., July 7; Nipissing Dist., May 20-Aug. 8; Renfrew Co., May 25-June 25; Carleton Co., Aug. 29; Welling- ton Co., May 30. Biological notes | Larvae hatch from overwintering eggs in early spring. The immature stages are restricted to small, cold, stenothermal streams, arising from a spring or bog. These streams warm up slowly so that larval growth is gradual. (The date of April 23, 1958, for mature larvae as previously re- ported by Davies and Syme (1958, p. 756 and Table V) should apply to P. fuscum). Larvae often pupate among the leaves of moss; their cocoons usually consist of but a few threads of silk, and naked pupae have been found in the bottom of micropools. Adults may emerge as early as May 25, and as late as August 8, in Algonquin Park, depending on the water tem- perature; there is only one generation annually (Davies and Syme, 1958). The females have well-developed mouthparts, and contain immature eggs and little stored nutrient on emergence. Females have been observed crawl- ing on humans and it appears that they require a blood meal for oogenesis. Prosimulium fuseum Syme and Davies Prosimulium fuscum Syme and Davies, 1958, Canad. Ent. 90: 702, 704, 706, Figs. la-c, 3, 11, 14, 21, 24-25 (female, male, pupa, larva). Holotype. Female, Type No. 6982, Canadian National Collection. Type locality. Kahshe River where it crosses Highway 11 south of Gravenhurst, Ontario. Pupa. collected April 27; adult emerged May 3, 1956 (P. D. Syme). Ontario distribution. Cochrane Dist., May 30-31; Nipissing Dist., April 23-May 31; Muskoka Dist., April 27-May 28; Haliburton Co., May 26; Simcoe Co., April; Hastings Co., April 29; Carleton Co., April 25-May 18; Wellington Co., April 4; Halton Co., April-May 18; Peel Co., April 1- 12; Wentworth Co., April 12-May 8. Biological notes The females oviposit in late May and early June, by tapping the tips of their abdomens to the water surface while in flight (Davies and Peter- son, 1956; Davies and Syme, 1958). Most of the eggs hatch from early October to early November and the larvae grow slowly throughout the winter, the majority reaching maturity by late winter (Davies and Syme, 1958; L. Davies, 1961). Larvae are found in a wide variety of streams, but occur most frequently in those over five feet wide, and especially at the outlets of lakes. L. Davies (1961) suggested that the thermal threshold 93 for pupation is higher than that for larval growth, resulting in an ac- cumulation of last stage larvae and an ultimate synchronization of emer- gence. The pupa is encased in a thick, but loosely woven covering of threads. Often the pupae are matted in groups on rocks, old logs and less often on vegetation. Emergence occurs from early April to early May in extreme southern Ontario, and from early May until the end of June in Algonquin Park (Davies and Syme, 1958). Males form mating swarms. Most females emerge with immature eggs but have large fat bodies and are thus autogenous for the first gonotrophic cycle. The peak of oviposi- tion occurs six to seven days after the peak of emergence (L. Davies, 1961). Shortly after the first oviposition, the females are attracted to mammals to obtain a blood meal for the second gonotrophic cycle, but only about 10 per cent of them lay a second batch of eggs (L. Davies, 1961). Larvae, pupae and adults of this species often show a high incidence of parasitism by mermithid nematodes. Prosimulium gibsont (Twinn) Simulium (Prosimulium) gibsonit Twinn, 1936, Canad. J. Res., Daas 108, 110° Fig. 1C, 1-3 (female, male, pupa). Holotype. Female, Type No. 4121, Canadian National Collection. Type Locality. Small stream near Carleton Place, Ontario. Pupa col- lected May 8; adult emerged May 10, 1935 (C. R. Twinn). Ontario Distribution. Parry Sound Dist., April 21; Nipissing Dist., May 18; Muskoka Dist., May 2-12; Frontenac Co., May 6-12; Lanark Co., May 10; Carleton Co., April 24-May 28; Wentworth Co., April 25- May 8. Biological notes Our studies indicate that the larvae of P. gibsoni probably hatch in late winter and early spring, and Anderson and Dicke (1960) reported that the eggs apparently resist desiccation and are in dormancy from early June until earl April of the next year. However, Hocking and Pickering (1954) stated that this species apparently overwinters in the larval stage at Churchill, Manitoba. In Ontario, larvae grow rapidly in the spring in clear, shallow, often temporary, streams that are 2-4 feet wide. The early larval stages are usually found on submerged trailing grass and reeds, or on objects exposed on the bottom. However, the last stage larva crawls to the bottom to pupate in protected crevices. The shapeless cocoon is com- posed of loosely woven silk to which particles of sand adhere; sometimes the cocoon consists of only a few strands (authors’ data; Twinn, 1936). Adults emerge in late April or early May, at water temperatures of about 55°F’, in south and central Ontario, but emergence is delayed until toward the end of June in extreme northwestern Ontario. There is one generation annually (authors’ data; Twinn, 1936; Anderson and Dicke, 1960). In fe- males, the mandibles are thin with weak teeth and the galae of the maxillae possess hair instead of teeth, so that it is unlikely that this species sucks blood. The eggs are usually mature in newly emerged females. {Prosimulium magnum Dyar and Shannon Prosimulium magnum Dyar and Shannon, 1927, Proc. U.S. Nat. Mus. 69 (10): 6, Plate 2, Figs. 1-2; Plate 3, Figs. 22-23 (female, male, pupa). Holotype. Male, Cat. No. 28326, U.S. National Museum. Type locality. Dead Run, Fairfax Co., Virginia (R.C. Shannon). Ontario distribution. Wellington Co., April 29; Wentworth Co., April 20-May 13. 94 Biological notes This univoltine species appears to be restricted to southern Ontario, and is particularly abundant in streams along the Niagara escarpment. It is also common in the Adirondack Mountains of eastern United States (Stone and Jamnback, 1955). In May, the female scatters her eggs (250 or more) freely into the water by tapping her abdomen to the water surface while in flight (Davies and Peterson, 1956, under the name of P. multidentatum). The larvae hatch in late winter, grow rapidly, and reach maturity in mid-April. The larvae attach to submerged rocks, sticks or trailing vegetation in streams that are 10-20 feet wide. They spin a thick, irregular mass of silk, the cocoon, which is somewhat thicker than that of P. fuscum. Often many pupae are massed together on rocks, wood, or other objects in the stream. Adults begin to emerge in late April, and the males form mating swarms (Davies and Peterson, 1956, under the name of P. multidentatum). The females, on emergence, have much stored nutrient and sometimes almost mature eggs. They have well-developed mouthparts, and one female feeding in a horse’s ear near Hamilton on May 20, was collected. Prosimulium mixtuwm Syme and Davies Prosimulium mixtum Syme and Davies, 1958, Canad. Ent. 90: 706- 708, Figs. 2, 4-5, 12, 15, 20, 22a-b (female, male, pupa, larva). Holotype. Female, Type No. 6983, Canadian National Collection. Type locality. Stream crossing 13th sideroad at Concession 6, Chingua- cousy Township, Peel Co., Ontaric, 2 miles N.W. of Terra Cotta. Pupa col- lected May 1; adult emerged May 6, 1956 (P. D. Syme). Ontario distribution. Nipissing Dist., May 4-27; Muskoka Dist., May 11-29; Grey Co., May 22-July 28; Simcoe Co., May 22; Victoria Co., May 12; Carleton Co.; Wellington Co., May 21; Halton Co. May 18-28; Peel Co., March 27-May 6; Wentworth Co., April 25-May 8. Biological notes Oviposition is performed by the female tapping her abdomen to the water surface while flying, at which time one to several eggs are released which sink into the water (Davies and Peterson, 1956; Davies and Syme, 1958). Most larvae hatch in early autumn but, in certain streams, some do not hatch until late winter (L. Davies, 1961). The early hatching lar- vae grow during the winter and reach maturity in early spring (Davies and Syme, 1958). Prosimulium mixtum is generally found in smaller, slow- er streams than P. fuscum. Pupae are frequently found buried in moss or other trailing vegetation, and are less strongly grouned and are covered with less silk than those of P. fuscum. Adult emergence begins in mid- April and continues into late June in some streams in Algonquin Park. The long, attentuated emergence in some streams may be explained by late hatching larvae (L. Davies, 1961) because there appears to be but one generation annually (Davies and Syme, 1958). Emergence is usually a few days later than that of P. fuscwm when the two species occur in the same stream. The females are anautogenous (L. Davies, 1961), feeding on the blood of mammals and occasionally birds to provide nourishment for the first gonotrophic cycle. L. Davies (1961) estimated that 20 per cent of the parous flies survived to complete a second ovarian cycle. Prosimulium multidentatum (Twinn) Simulium (Prosimulium) multidentatum Twinn, 1936, Canad. J. Res., D, 14: 106, 108, Fig. 1B, 1-8 (female, male, pupa). 95 Holotype. Male, Type No. 4120, Canadian National Collection. Type locality. Near Hull, Quebec, emerged from pupa May 3, 1935 CCAR Ewinn) : Ontario distribution. Nipissing Dist., May 17; Renfrew Co., May 5; Muskoka Dist., May 1-12; Carleton Co., April 12-May 21; Leeds Co., May 1-9; Halton Co., May 3-6; Wellington Co., May 6. Biological notes Larvae, whether they hatch in the autumn or late winter, pupate in late April or early May (authors’ records; Twinn, 1936), and adults emerge a few days later. The peak of emergence is about a week later than that of P. fuscum in a river with a temperature of 51°F. There is one generation per year. Females have strong, serrated mouthparts, and although having large fat bodies, and partly developed eggs on emergence, probably feed on mammalian blood. Mermithid nematodes often heavily parasitize this species (Twinn, 1936, 1939). Prosimulium vernale Shewell | Prosimulium vernale Shewell, 1952, Canad. Ent. 84: 33-36, Fig. 1A-H (female, male, pupa). Holotype. Female, Type No. 5987, Canadian National Collection. Type locality. Small, shallow stream draining an extensive Swamp and wooded area in flat farmland, Bell’s Corners, Ontario, May 9, 1950 (G. E. Shewell). - Ontario distribution. Carleton Co., March 21-May 19; Wellington Co., ay 6. Biological notes Most eggs probably hatch in the autumn and the larvae grow during the winter, often under a cover of ice (Shewell, 1961, pers. com.). The lar- vae concentrate at the base of submerged vegetation in streams only a few feet in width. Pupation occurs in April on bottom debris and stones. The cocoon is ‘‘a short, thinly woven sock covered with fine silt particles, enclosing only the abdomen” (Shewell, 1952). Adults emerge in the first half of May and the females possess immature eggs. Females have well- developed mouthparts and bifid claws which suggest that*they feed on birds. The eggs are laid in the spring and they remain in diapause until the autumn. There is one generation annually. Genus CNEPHIA Enderlein Cnephia abdita Peterson Cnephia abdita Peterson, 1962, Canad. Ent. 94: 96-102, Figs. 1-23 (female, male, pupa, larva). Holotype. Female, Type No. 7525, Canadian National Collection. Type locality. Small stream crossing Lake of Two Rivers Nature Trail approximately 14, mile north of Highway 60 at mile 20.0 from the west gate, Algonquin Park, Ontario, emerged from pupa collected June 3, 1959 (B. V. Peterson). Ontario distribution. Nipissing Dist., May 1-June 15; Renfrew Co., May 3-9; Muskoka Dist., May 2-June 6; Frontenac Co., May 6. Biological notes The overwintering eggs of this univoltine species hatch in late April at a temperature of about 35°F. The larvae usually are found near the 96 source of stenothermal, spring-fed streams, and in one stream were found in association with the larvae of T’winnia tibblest. A few larvae of Cnephia abdita have been found in small, warmer streams (50-60°F) which were 1-2 feet wide and flowed through open, grassy fields. In these warmer streams it was outnumbered by C. denaria n.sp. and even more so by other species (see those listed under C. denaria). Last stage larvae usually occur in these streams at the beginning of May, and adult emergence takes place in mid-May, a little after C. denaria. At 40°F, however, pupation occurs from mid-May to after mid-June, with adult emergence beginning by late May. The well-developed mouthparts and bifid claws of the females, and the undeveloped state of the eggs in newly emerged flies, indicates that this species probably feeds on the blood of b.rds. Cnephia dacotensis (Dyar and Shannon) Eusimulium dacotense Dyar and Shannon, 1927, Proc. U.S. Nat. Mus. 69 (10): 20-21, Plate 4, Figs. 48-51 (female, male). Cotypes. Two males, Cat. No. 28334, U.S. National Museum. Type locality. Brookings, South Dakota (J. M. Aldrich). Ontario distribution. Thunder Bay Dist., June 13; Nipissing Dist., May 25-June 2; Hastings Co., April 31-May 30; Lanark Co., May 27; Car- leton Co., May 13-June 14; Peel Co., June 23; Wellington Co., May 6-21. Biological notes Eggs of this univoltine species are laid in late May to mid-June. Most of the eggs hatch in early to mid-April of the following spring (Twinn, _ 1936; Davies, 1950), although a few may hatch in late autumn (Fredeen, 1961, pers. com.). In Wisconsin, first instar larvae are found in April shortly after the water temperature reaches 41°F (Anderson and Dicke, 1960). Larvae grow rapidly and are found mainly in streams over ten feet in width, and often near the outlets of lakes. Adult emergence is usually concentrated within a few davs in late May or early June (Davies, 1950). Females have reduced mouthparts (Krafchick, 1942; Nicholson, 1945), and on emergence have mature eggs (Davies and Peterson, 1956). Unlike most species, in which there are about equal numbers of the sexes, the males of C. dacotensis outnumber the females by about three to one (Davies, 1950). Mating takes place on objects near the stream within min- utes after emergence. Males and females often concentrate into masses, or balls, that fall into the water and this results in a high mortality (Davies and Peterson, 1956). Oviposition occurs within a few hours after emer- gence, the females making short flights to tap their abdomens to the water surface for the release of their eggs. This species is highly parasitized by mermithid nematodes. Ce denaria, new species Female. General body colour dark brown to blackish-brown, legs nearly concolorous with body, only slightly lighter brown. Length: body, 3.0 mm., wing, 3.5 mm. Head dark brown to blackish-brown, posterior and undersurfaces densely covered with long, whit:sh to pale yellow hair, lateral and medial margins of eyes with a row of coarse, erect, dark hair. Frons moderately broad, widening above, at narrowest part about one-half as wide as long, moderately covered with decumbent, whitish to pale yellow hair. Clypeus broader than long, moderately covered with semi-erect and decumbent, whitish to pale yellow hair. Antenna 10-segmented, entirely dark, with pale 97 pubescence but coarse hair dark; first flagellar segment the largest, distal segments tapering. Palpus dark blackish-brown, third segment enlarged, densely covered with dark hair; sensory vesicle somewhat less than one- half as long as segment, tube leading to exterior arising from distal tip of vesicle, of uniform width except at apex where it enlarges to form a mouth slightly wider than neck itself. Edges of mandible with about 50 fine ser- rations; galea of maxilla with about 28 large, retrorse teeth. Median space of buccopharyngeal apparatus shallow, broadly squared; dorsolateral arms moderately long, curving posteromedially, moderately sclerotized. Pronotum and prescutum concolorous or only faintly lighter than scutum, with moderately long, whitish to pale yellow hair. Scutum dark blackish-brown without anterolatera! spots or vittae, densely covered with short, fine, recumbent, pale yellow hair; hair on lateral margins longer and white; posterior region with long, coarse, dark hair interspersed among the pale hair. Scutellum concolorous with scutum, densely covered with shorter, pale hair mixed with long, coarse dark hair. Postscutellum concolorous with scutum, bare, shining. Pleuron concolourous with rest of thorax except for pleural membrane which is a lighter grayish-yellow colour; pleural tuft pale yellow; basisternum connected to proepisternum by a slender, precoxal bridge. Wing veins yellowish-brown, with fine hairs only, not interspersed with the usual wel!-developed spinules; hair on stem vein pale yellow, base of costa with mixed pale and dark hair; subcosta bare dorsally, hirsute ventrally; radial sector bare dorsally except for a short portion apically, ventral surface densely haired, fork of radial sector short and inconspicuous; basal cell present. Halter yellowish- to grayish- white, stem with pale hair. Legs nearly uniformly dark brown, only faintly lighter than thorax, covered with short, pale yellow hair and with a few longer, coarse, dark hairs present on hind margins of tibiae; tarsus with mixed pale and dark hair. Calcipala minute; pedisculus absent; hind basi- tarsus about five times as long as wide; claw long and slender, gently curved, with a prominent sub-basal, thumb-like projection that is about one-half as long as claw, and a shorter basal projection so that claw appears trifid. Dorsum of abdominal segments dark blackish-brown, remainder of abdomen lighter yellowish-to grayish-brown; tergites 3-5 reduced, 6 less so, all moderately covered with short. pale yellow hair, the last two with some long, coarse, dark hair on posterior margins; rest of abdomen rather sparsely covered with short, pale yellow hair; sternite 1 short, postero- lateral margins rounded, anterior and posterior margins straight; sternites 7-8 heavily sclerotized. Fringe of basal scale pale yellow, short dorsally, long laterally. Anal lobe lightly setose, L-shaped, very narrow dorsally, broadening ventrally at about the level of the ventral margin of cercus, with a slight anteroventral projection, posteroventral region produced only a short distance under cercus (Fig. 19). Cercus large, about twice as wide as long, densely setose. Ovipositor flaps very short, pale white, medial and hind margins straight, flaps situated close together. Genital fork Y-shaped, with infilling at point of bifurcation of arms; stem narrow, heavily sclero- tized; arms broader, lightly sclerotized, apical portion of each arm some- what rounded with a short, irregular, internal, sclerotized ridge or tooth. Male. Similar in size to female; general body colour darker blackish- brown. Posterior and undersurfaces of head, frons and clypeus densely covered with long to moderately long, dark hair. Antenna dark with dark pu- bescence; first segment of flagellum slender, conspicuously longer than other segments. Palpus dark, with dark hair. 98 Thorax uniformly dark blackish-brown except for pleural membrane which is light yellowish- to grayish-brown; anterior one-third of scutum with moderately long, fine, semi-erect to erect, dark hair; central one-third with short, recumbent, dark hair; posterior one-third of scutum, and scu- tellum densely covered with long, coarse, erect, dark hair; postscutellum bare, shining; pleural tuft dark. Hair on wing veins entirely dark, subcosta bare both above and below. Legs slightly lighter than thorax, with dark hair, posterior margins of femora and tibiae with long, dark hair; hind basitarsus about four times as long as wide. Dorsum of abdominal segments dark brown, sub-shining, rather densely covered with moderately long, dark hair; sternum 2 membranous, other sterna with sclerotized sternites ; sternites 3-7 bearing moderately long, dark hair; lateral margins of sternite 1 rounded, the anterior and posterior margins straight, the posterior mar- gin shorter. Fringe of basal scale dark, the hair short dorsally, long lateral- ly. Basistyle (Fig. 60) large, conic-quadrate, lightly setose on distal one- half; attached to the inner ventral margin is a slender, triangular plate with a long, slender, heavily sclerot:zed, bluntly pointed rod that is di- rected posteroventrally and terminates near arms of median sclerite. Dististyle four-fifths the length of basistyle, triangular in cross-section, broad basally, at about distal one-third cf its length it abruptly tapers distally into a long, slender point with a single apical spine. Ventral plate with a short, pointed, ventrally recurving lip; ventral plate, in ventral view, exclusive of basal arms, slightly wider than long; basal arms short, bluntly pointed. Median sclerite Y-shaped, stem relatively broad, arms short, each with a sclerotized ridge apically. Pupa. Length about 4.0 mm. Respiratory organ about 2.0 mm. long, composed of 22 filaments arising from three main trurks, the dorsal trunk with 10 filaments, lateral trunk with four filaments, and ventral trunk with 8 filaments; the filaments branching regularly some distance from the base, diverging outwards and upwards. Tergites 2-5 with eight fine, pale hooks on their posterior margins; tergites 5-8 usually with an anterior row of very fine, pale, spine-like hooks, these may be absent on some segments; sternites 6-7 each with four fine, pale hooks. Terminal spines pale, gently curved so they project dorsally and slightly anteriorly, tips diverging; about three stout setae on each side just behind and below terminal spines. Holotype. Female (mounted on slide), reared from a pupa collected May 3, 1961, from a small stream one mile west of Renfrew, Renfrew Co., Ontario, B. V. Peterson and E. Bond. Allotype. Male, reared from pupa collected May 6, 1961, from a stream 9.2 miles east of Kaladar, Frontenac Co., Ontario, B. V. Peterson and E. Bond. Paratypes. One male, same data as allotype; one female same data as allotype except collected by D..M. Davies and D. M. Wood. One male (pin- ned), reared from a pupa collected May 4, 1959, from a small stream three miles south of Huntsville, Muskoka Dist., Ontario, D. M. Davies and D. M. Wood; one male and one female (pinned), same data excepted collected May 2, 1960. Types (No. 7995) and paratypes deposited in the Canadian National Collection. Paratypes deposited in the U.S. National Museum. Comparison with related species This species, like C. abdita, possesses a combination of characters which does not allow its easy assignment to genus. The absence of spinules on the anterior wing veins, and the fork of the apical portion of the radial sector, though short and inconspicuous, are features common to the genus Prosimulium (Stone and Jamnback, 1955). However, the indistinctness of 99 this fork and the fact that such a fork is evident in specimens of C. daco- tensis and C. invenusta, and the presence of a minute calcipala, the com- plete precoxal bridge, and the structure of the genitalia, are features typi- eal of the genus Cnephia. The larva (which is described in Part 2 of this paper) is quite different from all Prosimulium larvae, and closely re- sembles the larva of Cnephia abdita. The hypostemia! teeth of both these species are similar to those of C. mutata. Also, the basal two antennal seg- ments which are coloured, and the larval abdomen with its two, large, ven- tral papillae, strongly suggest that this species is more closely related to the Cnephia and Simulium (Husimulium) than it is to the Prosimulium. Thus, we place this species in the genus Cnephia. Adults of both sexes of C. denaria are readily distinguished from all other North American species of Cnephia on the basis of their 10-seg- mented antennae and their genitalia. The pupa is also sufficiently distinct to present no difficulty in its determination. Adults of C. denaria are easily separated from North American species of Prosimulium However, this species might be confused with Prosimulium unicum (Twinn), and P. decemarticulatum, both of which have 10-segmented antennae. Prosimulium unicum, which was described from a single female from Utah, has simple claws and elongated ovipositor flaps. Prosimulitum decemarticulatum fe- males have conspicuously yellow to orangish antennae and legs, while those of Cnephia denaria are dark brown. In addition, the basisternum of the female of C. denaria is connected to the proepisternum, on each side, by a slender, precoxal bridge. The precoxal bridge is present in all males of Ontario Prosimulium, but it is not present in any of the females. Biological notes Little is known of the biology of C. denaria. The pupa from which the female holotype was reared, was collected near Renfrew, cn May 38, 1961, in a small, shallow, muddy bottomed, drainage stream that flowed through open pasture land. The stream contained considerable trailing grass, other vegetation, and various kinds of debris. The water temperature was 51°F. Immature stages were also collected three miles south of Huntsville, and 9.2 miles east of Kaladar in streams 1-2 feet wide with sandy or pebbly bottoms, flowing through, or at the edge of, open cultivated fields. The water temperature was about 50°F at the first site during late April, and about 60°F at the second in early May. Pupae were usually taken from the underside of pebbles. Associated species, at about the same stage of development, were C. abdita, and in greater numbers Prosimulium gibsont, Simulium congareenarum, S. excisum n.sp., S. rivuli, as well as younger stages of several other species. Cnephia denaria appears to be an early spring species because mature larvae were collected on April 18, and adults were reared on May 1, but some pupae were also collected as late at May 11. Newly emerged females have well-developed mouthparts, 1m- mature eggs and much stored nutrient. These facts, together with the presence of bifid claws, indicate that this species probably feeds on avian blood. {Cnephia emergens Stone Cnephia emergens Stone, 1952, Proc. ent. Soc. Wash. 54: 80-81 (fe- male, male). Holotype. Female, Cat. No. 61189, U.S. National Museum. Type locality. Fairbanks, Alaska, June 19, 1948. Ontario distribution. Kenora Dist. (Patricia Subdist.), June 22; Thunder Bay Dist., June 13. 100 Biological notes In north and central Ontario, larvae appear to hatch in the spring, which agrees with observations made in Alaska by Sommerman et al. (1955). Immature larvae, probably of this species, were collected May 30- 31, in the Moosonee area of Ontario. At Big Trout Lake, Patricia Subdis- trict, a pupa and three exuviae were collected on June 22. A little farther north, at Churchill, Manitoba, adults emerged from June 23 to July 15 (Ide et al., unpublished manuscript), which is slightly later than reported by Hocking and Pickering (1954) for the same locality. Cnephia invenusta (Walker) Simulium invenustum Walker, 1848, List Diptera, Brit. Mus. 1: 112 (female, male). Holotype. ? Male, British Museum, London, England. Type locality. St. Martin’s Falls, Albany River, Ontario, 1844 (G. Barnston). Ontario distribution. Kenora Dist. (Patricia Subdist.), June 20; Nip- issing Dist., April 2-June 13. Biological notes Eggs, which are laid in the spring, presumably hatch in late summer or early autumn and the larvae develop to maturity by late winter. The im- mature stages are found in swiftly flowing, usually unbroken waters of permanent streams over ten feet wide. The young larvae may be near the bottom sediment and when nearing maturity, crawl up on rocks or, more often, on logs or alder trunks which are at a somewhat oblique angle 2-4 feet under water. The mature larva spins, possibly around detri- tus, a thin cylindrical tube, which is less than 0.5 mm. in diameter and 10- 15 mm. in length, and is attached to the substrate by a holdfast (authors’ data; Wolfe and D. G. Peterson, 1959). The larva spins a pocket-shaped cocoon on this stalk. Larvae are easily dislodged from their stalks, and 0c- casionally this-results in bare stalks or two pupae occurring on one stalk. Under certain conditions, adult emergence begins before April 22, and may continue a few days beyond May 4. This species has one generation annually, and is the earliest species to emerge in Algonquin Park. The females have well-developed mouthparts and bifid claws, and on emergence their ovaries contain immature eggs. These features indicate that it feeds on avian blood, a fact which has been confirmed by Bennett (1960). Cnephia mutata (Malloch) Prosimulium mutatum Malloch, 1914, U.S. Dep. Agric., Bur. Ent., Tech. Ser. 26: 20-21, Plate 2, Fig. 18 (female). Holotype. Female, Cat. No. 15404, U.S. National Museum. © Type locality. Glassboro, New Jersey, March 28, 1910 (C. T. Greene). * Ontario distribution. Kenora Dist., June 15; Thunder Bay Dist., June 13 (exuviae) ; Cochrane Dist., May 30; Algoma Dist., June 13 (exuviae) ; Nipissing Dist., April 19-Aug. 4; Muskoka Dist., May 1-28; Bruce Co., May 13; Hastings Co., April 29-May 26; Lanark Co., June 23; Carleton Co., May 4-23; Wellington Co., April 4-June 18; Peel Co., April 12-May 27; Middlesex Co., May 4; Wentworth Co., April 28-May 3; Welland Co., June Zo. Biological notes _ In this species both diploid and triploid forms occur, both forms often living in the same streams (Basrur and Rothfels, 1959). Most of the in- dividuals (90-100%) collected are triploid and these are parthenogenetic 101 (Davies, 1950; Davies and Peterson, 1956). The diploid ferm, at least, is univoltine (Basrur and Rothfels, 1959). Females lay their eggs by tap- ping their abdomens to the water surface while in flight (Davies and Pe- terson, 1956). These authors found oviposition to occur in the spring (late May and early June) although a female with mature eggs was netted on August 4. Basrur and Rothfels (1959) reported that the eggs are in dia- pause until late fall or early winter in Peel County, and that young larvae appear in January or early February. They found that in some streams the early larvae, which matured in late March and early April, were almost all of the diploid form. Thereafter, the triploid form began to in- crease, and by mid-April the mature larvae were almost entirely triploid, but diploid larvae continued into early May. Anderson and Dicke (1960) reported that in temporary streams of southern Wiscensin, larvae hatched from overwintering eggs in early April, but in small streams of the nor- thern forest the larval stage overwinters. Larvae occur on the undersides of submerged rocks and trailing foliage, and pupate in crevices of, and under, objects on the stream bottom, and sometimes between the blades of submerged grass. The cocoon consists of a loose, fibrous bag which covers about three-fourths of the pupa, and often has a few grains of sand ad- hering to it. This species outnumbers other species early in the year in smaller streams, but often in larger, faster streams is itself outnumbered by Prosimulium fuscum, P. mixtum and Simulium vittatum. In Algonquin Park, Davies (1950, p. 138) collected adult males and females of the diploid form emerging in mid-May from Smiths’ Lake Inlet, a cold, bog-fed stream, at the same time as Prosimulium fuscum but earlier than P. mixtum and P. fontanum (Davies and Syme, 1958). The small peak of females of Cnephia mutata emerging here in late May, may have been the triploid form. In Costello Creek, only females (presumably triploid) emerged from early May to the end of June, with one in early August (Davies, 1950). This attentuated emergence may result from overwintering eggs rather than a second generation as suggested by Basrur and Rothfels (1959). Emerging females contain much stored nutrient and half-grown eggs. However, they have well-developed mouthparts and have been taken while feeding in the ears of deer (Davies and Peterson, 1956) and of horses. Cnephia ornithophilia, new species Cnephia (Cnephia) “U’ Bennett, 1960, Canad. J. Zool. 38: 380 (fe- male bloodsucking habits). Female. General body colour dark brown to blackish-brown, pruinose ; legs lighter, yellowish-brown to orangish-brown. Length: body, 4.2-5.5 mm., wing, 4.2-5.0 mm. Head dark brown to blackish-brown, posterior and undersurfaces sparsely covered with moderately long, yellow hair. Frons narrow, widen- ing above, at narrowest part one-third or less its length; sparsely covered with short, decumbent, yellow hair. Clypeus as broad as long, sparsely covered with decumbent, yellow hair. Antenna long, 11-segmented, with pale pubescence, coarse hair dark; segments all subequal in size, bead-like, scape and pedicel orangish-brown, contrasting with dark flagellum. Palpus dark blackish-brown, with mixed yellow and dark hair; third segment swollen, sensory vesicle large, about one-half as long as segment, neck of sensory vesicle arising near middle of vesicle, expanding distally to form an enlarged opening to the exterior. Edges of mandible with about 50 ser- rations; galea of maxilla with about 30 large, retrorse teeth. Median space of buccopharyngeal apparatus shallow, narrowly U-shaped; dorsolateral arms very short, flaring outwardly, heavily sclerotized. 102 Pronotum and prescutum yellowish-brown, lighter than scutum, with moderately long, yellow hair. Scutum dark brown to blackish-brown, prui- ‘nose, with sparse, recumbent, yellow hair, about posterior one-fourth with longer, yellow and black, coarse hair; scutum with three pale vittae, median one linear, the two submedian vittae slightly curved outwardly, all three fading both anteriorly and posteriorly. Scutellum lighter than scutum, w:th long, semi-erect,dark hair. Postscutellum shining brown, only slightly darker than scutellum. Pleuron concolorous, or slightly lighter than scutum especially on pleural membrane and area around pleural tuft; pleural tuft yellow. Wing veins light brown; all hair on veins dark; subcosta bare dor- sally, but with a single row of about 20 hairs ventrally; radial sector bare dorsally except for a few hairs on distal tip, ventral surface with numerous hairs; basal cell present. Fringe of calypter and alar lobe yellow. Halter yellowish-white, stem light brown with yellow hair. Legs nearly uniformly yellowish- to orangish-brown, with short, yellow hair, tarsi with mixed yellow and dark hair; calcipala short, rounded; pedisulcus absent; hind basitarsus about 6.5 times as long as wide; claws moderately long, gently curved, with a thumb-like, basal projection extending about one-half length of claw. 3 Abdomen light brown, pruinose, paler on anterolateral and ventral surfaces, tergites 2-5 somewhat reduced, nearly square in shape, sparsely covered with short, yellow hair, terminal segment and lateral regions of abdomen with long, dark hair, ventral surface with short, dark hair; ster- nite 1 sclerotized, evenly and broadly rounded on posterior margin, an- terior margin straight; sternite 8, and occasionally 7, lightly sclerotized. Fringe of basal scale pale yellow. Anal lobe narrow dorsally, broadening ventrally to about twice width of cercus, anterior margin nearly straight or with a slight anteroventral projection, posterior margin concave, extending only slightly under cercus, ventral marg:n broadly rounded with an inter- nal notch or fold so that it is bilobed, the anterior lcbe extending below posterior lobe; moderately setose on posteroventral region (Fig. 23). Cer- cus twice as wide as long, posterior margin slightly concave, moderately setose. Ovipositor flaps triangular in outline, somewhat separated and apices diverging, medial margins of flaps slightly concave, slightly sclero- tized, with scattered short setae. Stem of genital fcrk slender, heavily sclerotized, arms broader, L-shaped, lightly sclerotized except for a heavily sclerotized ridge on posterior margin. Spermatheca a iarge, rounded, thin- walled sac with a reticulate pattern. Holotype. Female (mounted on slide), Wildlife Research Station, Al- gonquin Park, Nipissing District, Ontario, May 27, 1959 (ex Blue Jay), G. F. Bennett. Paratypes. One female (pinned) (from emergence cage), May 20, 1949, D. M. Davies. One female (pinned), May 28, 1956; one female (pinned), May 31, 1956; two females (pinned), June 13, 1956; one female (pinned), May 24, 1957, all D. M. Wood. Three females (ex Blue Jay), one female (ex Ruffed Grouse), one female (ex Sharpshinned Hawk). June 3, 1958; one female (ex Ruffed Grouse), June 11, 1958,-all G. F. Bennett. Sixteen females (ex Blue Jay), May 27, 1959; two females, May 27, 1959; fourteen females (ex Pekin Duck), May 27-28, 1959; three females (ex Pekin Duck), May 30, 1959; two females (ex Robin), June 2, 1959; three females, June 2, 1959; all G. F. Bennett. Three females, June 4, 1959, B. V. Peterson. All the above records are from the type locality. One female, Lake of Two Rivers Nature Trail, Algonquin Park, Ontario, June 2, 1959, B. V. Peter- son. Holotype (No. 7996) and paratypes deposited in the Canadian National 103 Collection. Paratypes deposited in the U.S. National Museum, McMaster University, and the British Museum. Comparison with related species Cnephia ornithophilia females closely resemble the females of C. pecu- aria (Riley), C. invenusta and C. taeniatifrons (Hnderlein). Differences in the genital rod, color variations, and the shape of the buccopharyngeal apparatus and of the sensory vesicle of the third palpal segment easily dis- tinguish C. ornithophilia and C. invenusta. The shape of the genital rod, color variations, and the narrow, inverted V-shaped structure of the first abdominal sternite readily separate C. taeniatifrons from C. ornithophilia. Cnephia ornithophilia is evidently more closely related to C. pecuaria than to the other two species, and are difficult to separate. The most reliable characters for distinguishing these two species are the shape and size of the first abdominal sternite, and of the buccopharyngeal apparatus. In C. ornithophilia the first abdominal sternite is large and broadly triangular in shape, the anterior margin being straight and the posterior margin narrowed and rounded. This sternite in C. pecuaria is more slender and trapezoidal in shape; the lateral margins may be rounded but the anterior and posterior margins are straight or slightly sinuous. The median space of the buccopharyngeal apparatus of C. ornithophilia is shallow and nar- rowly U-shaped; the ventral sclerotization of the two dorsolateral arms rather closely approach each other at the median space. In C. pecuaria the median space of the buccopharyngeal apparatus is shallow, but it is broadly squared; the ventral sclerotization of the dorsolaterai arms does not ex- tend into the median space. Cnephia ornithophilia is also generally larger than C. pecuaria. Biological notes The first specimen of C. ornithophilia was collected by D. M. Davies from an emergence cage placed ina series of rapids just below Lake Sasa- jewun Dam in Algonquin Park, on May 20, 1949. This single female was, at that time, tentatively identified as C. dacotensis and was collected in association with large numbers of the latter species. Females were taken by D. M. Wood in 1956, and subsequently by G. F. Bennett, feeding on various birds in the Lake Sasajewun region. Little is known about the biology of C. ornithophilia except for the data on the feeding habits of the female, published by Bennett (1960) under the name of Cnephia (Cnephia) “UVU”’. Genus SIMULIUM Latreille Simulium aestivum, new species Female. A small, brown and gray pollinose species with pale yellow hair, sparsely haired abdomen and narrow frons. Length: body, 2.0-2.5 mm.; wing, 2.5-3.0 mm. Posterior surface of head, frons and clypeus gray pollinose; ventral half of clypeus and dorsal half of frons with decumbent, yellow hair. Frons narrow, about one-ninth the width of head. Antenna and palpus uniformly dark grayish-brown pollinose. Flagellum of antenna with pale pubescence, and longer, pale hairs basally. Hair of palpus nearly all brown; sensory vesicle of third segment about one-half the length of the segment. Scutum gray pollinose, covered with recumbent, uniformly pale, yellow hair. Scutellum with long, erect, yellow hair, interspersed with a few darker ~ ones. Postscutellum bare, lightly pollinose, brown, shining. Pleuron gray- ish-brown pollinose; pleural membrane and subalar area dull brown. Pleu- ral tuft and hair on pronotum and proepisternum long, erect, pale yellow. 104 4 ee Hair on stem vein pale yellow, interspersed with a few dark hairs; hair on dorsal surface of radius black; ventral surface of subcosta and radial sec- tor with dark hair. Legs brown, tars: darker brown; basal segments with pale yellow hair, hair darker on the distal tips of the tibiae, mostly dark brown on the tarsi. Claw with a large, basal, thumb-like projection. Calci- pala and pedisculus well-developed. Abdomen brown, tinged with a grayish-brown pollinosity, more pro- nounced on second tergite. Basal fringe pale yellow, hair on second and third tergites short, pale yellow; hair on remaining segments short, sparse, recumbent, entirely brown apically. Genitalia as in Fig. 36. Arms of genital fork moderately broad at point _ of bifurcation; posteromedial areas of terminal plates large ‘and rounded, or bluntly angulate. Male. Similar in size to female. General body colour dark brown, with gold hair on scutum. Posterior surface of head, frons and clypeus dark grayish-brown pol- linose, with erect, brown hair. Antenna dark, with pale pubescence on flagellum, scape and pedicel with dark hair. Palpus with dark hair, third segment dark brown, distal segments paler; sensory vesicle of third seg- ment minute, less than one-sixth the length of the segment. Central portion of scutum dull blackish-brown, margins of scutum, pleuron, scutellum and postscutellum paler grayish-brown pollinose. Hair of pronotum and proepisternum gold, long, erect. Scutum covered with short, fine, recumbent gold hair. Scutellum with black, long, erect hair laterally, interspersed with shorter gold hair. Postscutellum and katepi- sternum bare. Pleural tuft brown, with pale tips. Legs brown, concolorous with thorax (paler in teneral specimens). Hair on fore coxa gold, inter- spersed with a few darker hairs; hair on femora and tibiae, and mid- and hind coxae dark brown, interspersed with a few gold hairs; tarsi with dark hair. Calcipala present; pedisulcus well-developed. Abdominal tergites dull brown in both lateral and terminal views, gray pollinose only on second tergite; lateral regions and sternites paler, gray pollinose. Tergites 2-6 with long, erect, brown hair, this paler, shorter and recumbent posteriorly; sternites with brown, erect, sparse hair. Genitalia as in Fig. 71. Clasper dark brown with black hair; dististyle enlarged and rounded terminally, with a flattened, triangular flange medi- ally, the small spine at its apex directed anteromedially. Paramere broadest at base with a concave ventral margin, the apex produced ventrally and bearing a long, dorsally recurved spine. Median sclerite weakly forked, often with infilling between the arms. Dorsal sclerite clavate, three or more times as long as wide. Pupa. Respiratory organ about 3.0 mm. long, composed of 4 filaments in two, petiolate pairs; the peticle of the ventral pair slightly longer and thinner than petiole of dorsal pair. All four filaments closely subparallel, rugose, gray and subshining. Cocoon sl.pper-shaped, with a thickened an- terior margin. Holotype. Female, reared from a pupa collected June 25, 1959, from a small stream flowing into the Ottawa River at the North Star Lodge, Point Alexander, Rolph Twp., Renfrew Co., Ontario, D. M. Davies and D. M. Wood. Allotype. Male, same data as holotype. Paratypes. Fourteen males, eight females, same data as holotype. Three males, four females, from a small stream crossing the Laurentian Point Road, three miles west of Point Alexander, Rolph Twp., Renfrew Co., 105 Ontario, June 25, 1959, D. M. Davies and D. M. Wood. Types (No. 7992) and paratypes deposited in the Canad.an National Collection. Paratypes deposited in the U.S. National Museum, and McMaster University. Ontario distribution. Thunder Bay Dist., June 13; Nipissing Dist., June 8-21; Renfrew Co., June 22-25. Comparison with related species This species appears to be intermediate between Simulium pugetense and S. latipes, the male and larva closely resembling the latter. The lip of the ventral plate is narrower than that of S. latepes, and is more weakly developed than the lip of S. pugetense. The median sclerite is not deeply forked, often with infilling between the arms making it appear unforked. Biological notes This species is univoltine. The eggs are laid in early summer, and the larvae hatch the following spring. In one stream near Deep River, no larvae were found on April 21, although they were present on May 28. Adult emergence begins in early June and continues into late June at least. The larvae are found in small, clear, cool, stenothermal streams which usually arise from a bog or spring source and pass through moderately dense woods. The females have well-developed, piercing mouthparts, and on emergence have immature eggs and little stored nutrient. Simulium aureum Fries Simulia aurea Fries, 1824, Observationes Entomologicae 1 : 16 (fe- males, male). Cotypes. ? Two females, Zoological Institute, University of Lund, Lund, Sweden. Type locality. The types were collected by Zetterstedt in Scania, Swe- den from Esperod and Bjornstorp. Ontario distribution. Kenora Dist. (Patricia Subdist.), June 21-25; Kenora Dist., June 16-29; Cochrane Dist., June 26-27; Manitoulin Dist., Aug. 4-5; Nipissing Dist., May 24-Oct. 9; Muskoka Dist., May 20-July 4; Bruce Co., June 12-Sept. 1; Simcoe Co., May 28-Oct. 9; Ontario Co., May 25; Hastings Co., July 3-Oct. 14; Lanark Co., May 18; Carleton Co., May 25-Oct. 23; Prescott Co., July 25; Wellington Co., May 20; Peel Co., May 14- Oct. 5; York Co., June 22-July 1; Northumberland Co., Sept. 17; Went- worth Co., Oct: 4-22. : Biological notes Simulium aureum consists of seven cytological forms (five in North America) of which at least three occur in Ontario (Dunbar, 1958, 1959). It is highly probable that none of the forms occurring in Ontario are con- specific with the form originally described under this name. Although the seven forms can be distinguished by inversions in their salivary gland chromosomes, their separation on a morphological basis has yet to be accomplished with any degree of certainty. Simulium aureum form “A” is found in many parts of southern and central Ontario (Dunbar, 1958), and is the only form that has been con- firmed cytologically to occur in Algonquin Park. Here it has at least two generations annually (Davies, 1950). The overwintering eggs hatch in the spring and larvae can be found from May 4-October 30 (Dunbar, 1958), in slow, clear, small to medium sized, usually permanent streams and are attached to submerged vegetation or other objects. Adult emergence begins in early to late June and continues into October. However, one female, 106 collected dead after presumed oviposition, was found as early as May 22 (Davies and Peterson, 1956). Females of form ‘‘A”’ feed on birds, with most feeding occurring in trees about 20 feet above the ground (authors’ data; Bennett, 1960). Bloodsucking continues at least until September 16. Females with immature eggs and nectar-filled crops were netted over the middle of Lake Sasajewun on June 14 and August 5 (Davies and Peterson, 1957). Females may oviposit while in flight (Davies and Peterson, 1956) but prefer to lay their eggs on grass or leaves trailing in the water in pro- tected sites. Oviposition continues at least until September 22. Simulium aureum form “B” occurs in southern Ontario, often in the same stream and at the same time as form “‘A’’. Little is known of the biology of form “B’’, but larvae have been found in various streams from May 4-October 30 (Dunbar, 1958), and last stage larvae occurred on May 16 in a stream having a temperature of 72°F. This indicates that it may have two or more generations annually. Simulium aureum form “C” has been found at Churchill, Manitoba (Dunbar, 1959), and although it may occur in the extreme northern part of Ontario, it has not yet been found. Simulium aureum form “D” is found in small streams draining mus- keg meadows, and larger streams draining shallow lakes of the Patricia portion of the Kenora District. Although larvae were still present on June 25, adult emergence had begun prior to June 22. At Churchill, Manitoba, larvae were found from June 7 to July 15 (Dunbar, 1959). {Simulium baffinense Twinn Simulium (Husimulium) baffinense Twinn, 1936, Canad. J. Res., D, 14; 121-123, Fig. 8A, 1-5 (female, male). Holotype. Female Type No. 4126, Canadian National Collection. Type locality. Lake Harbour, Baffin Island, August 10, 1935 (W. J. Brown). Ontario distribution. Kenora Dist. (Patricia Subdist.), June 18-27 (larvae only). Biological notes This species is reported for the first time from Ontario, where it occurs in the northwest, at Big Trout Lake, in the Patricia Subdistrict. It may overwinter in the egg stage as it is thought to do in Alaska (Sommer- man et al., 1955) and in Utah (Peterson, 1959b). Third to fourth stage larvae were found from June 18 to 27, 1961, in two streams draining the muskeg on the north shore of the lake. Larvae were found on July 12, in the head waters of Goose creek, near Churchill, Manitoba (Dunbar, un- published notes), and pupae were present until July 20 (Hocking and Pick- ering, 1954). The female has reduced mouthparts, and on emergence con- tains immature eggs and much stored nutrient. tSimulium congareenarum (Dyar and Shannon) Eusimulium congareenarum Dyar and Shannon, i927, Proc. U.S. nat. Mus. 69(10): 20, Plate 4, Fig. 45 (female). Holotype. Female, Cat. No. 28333, U.S. National Museum. Type locality. Congaree, Richland Co., South Carolina. Ontario distribution. Kenora Dist. (Patricia Subdist.), June 18-27; Kenora Dist., June 15; Cochrane Dist., June 28-29; Algoma Dist., July 1 (exuviae) ; Nipissing Dist., May 13-June 21; Muskoka Dist., May 12-18; Bruce Co., June 8-July 10; Frontenac Co., May 6. 107 Biological notes Morphological and cytological evidence indicates that this species is a complex (authors’ data; Dunbar, pers. com.). This species probably - overwinters in the egg stage with hatching beginning early in April. Lar- vae are about half-grown by the end of the month in streams having tem- ~ peratures of 55-65°F'. Pupation starts in the first week of May and adults begin to emerge during the second week. Under cooler conditions, these events may be delayed two to three weeks. In the Patricia Subdistrict, lar- vae and pupae were found from mid- to late June. Simuliwm congareenarum may have two generations in some streams of southern Ontario; a pre- sumed second generation occurred on the Bruce Peninsula with July 10, being the midpoint of pupation. Females of this species have been obtain- ed in mid-June over the middle of Lake Sasajewun, especially in the even- ing, with other species of Simulium (Eusimulium) (Davies and Peterson, 1957). They fed on birds, especially domestic ducks (authors’ data; Ben- nett, 1960), from mid-May to mid-June, but are more commonly found feeding in late May. A female with mature eggs was coliected around a Pekin duck on May 26. Simulaum corbis Twinn Simulium (Simulium) corbis Twinn, 1936, Canad. J. Res., D, 14: 147- 148, Fig. 15B, 1-5 (female, male, pupa). Holotype. Female, Type No. 41381, Canadian National Collection. Type locality. Blanche River, about five miles south of Perkins Mills, Quebec. Pupa collected May 22; adult emerged May 26, 1935 (C. R. Twinn). Ontario distribution. Thunder Bay Dist., June 13-July 1; Cochrane Dist., June 2 (exuviae) ; Nipissing Dist., May 25-July 8. Biological notes This species is seldom collected in southern Ontario, has been report- ed as rare in New York State (Stone and Jamnback, 1955), and is restricted to the northern forested regions of Wisconsin (Anderson and Dicke, 1960). In many seasons of collecting in Algonquin Park, the authors have ob- tained only two adult females. One female was reared from a pupa collect- ed on May 21, at a water temperature of 65°F, at a time close to the emer- gence date reported by Twinn (1936), and the other was netted on July 8. However, collections in seven streams and rivers along the north shore of Lake Superior yielded larvae, pupae and a few exuviae in mid-June, at a water temperature of 55°F, and larvae were still present in this area on July 1, although exuviae were predominant. At Moosonee, larvae, as well as exuviae, were found on June 27. Whether this species is multivoltine in Ontario is not known. In Wisconsin it is univoltine and eggs overwinter (Anderson and Dicke, 1960), but in Alaska it may have two generations (Sommerman et al., 1955). This species occurs more abundantly in rivers over 20 feet in width and appears to be more common on the northern edge of southern Ontario. It is found in association with S. quebecense, S. tuberosum (sensu lato), S. venustum and sometimes with S. longistylatum. The pupal cocoons are unusually firmly attached to rocks and sticks. On emergence, females have undeveloped ovaries, a moderate to large sized fat body, and also possess well-developed mouthparts for sucking blood. Eggs are laid singly by the females as they fly over rapids (Wolfe and D. G. Peterson, 1959). Overwintering probably occurs in the egg stage, as is thought to be the case in Alaska (Sommerman et al., 1985)... 108 Simulium croxtont Nicholson and Mickel Simulium croxtoni Nicholson and Mickel, 1950, Tech. Bull. Univ. Minn. agric. Exp. Sta. 192: 41-42, Fig. 20A-B (female. pupa). Holotype. Female, University of Minnesota. Type locality. West of International Falls, Koochiching Co., Minnesota, June 2, 1941 (reared). . ‘ Male. General body colour blackish-brown with gold hair on the scu- tellum. Scutum dull black, gray pollinose on margins; hair on central portion short, recumbent, golden; hair along lateral margins paler and slightly longer, anterior margin and humeri with still paler yeilow hair. Pronotum, proepisternum and fore coxa with almost white hair. Pleu- ron pale gray pollinose. Pleural tuft with mixed pale and dark hair. Kate- pisternum bare. Legs brown; hair mostly brown, mixed with pale yellow hair on front femur and tibia and on anteroventral surfaces near the junc- tions of mid- and hind femora and tibiae. Abdominal tergites grayish-brown pollinose in lateral view, becoming dull brown in posterior view except on the second tergite which remains pollinose. Genitalia as is in Fig. 34. Dististyle rather long. Body of ventral plate narrowing posteriorly, the small, central, hirsute lip projecting as a small tubercle beyond the distal margin. Ontario distribution. Kenora Dist. (Patricia Subdist.), June 23-27; Kenora Dist., June 15-29; Cochrane Dist., June 26-29; Manitoulin Dist., June 12; Nipissing Dist., May 21-June 20; Muskoka Dist., May 20-July 4; Bruce Co., June 8-July 10; Ontario Co., May 25-June 6; Hastings Co., June 12; Lanark Co., May 18; Carleton Co., May 25-June 12; York Co., June 8; Wentworth Co., May 24. Biological notes Larvae hatch in the spring from overwintering eggs, and develop. in both temporary and permanent streams from 2-15 feet in width. Pupation occurs in the second half of May and adults emerge from May 20-June 12. In some streams of southern Ontario there appears to be a second genera- tion as mature pupae were found on July 10. In central Ontario first pupa- tion is delayed until late June where there may be only one generation as is reported for central and northern Wisconsin (Anderson and Dicke, 1960). Females have well-developed mouthparts and bifid claws. When newly emerged, they have immature eggs and much stored nutrient. They have been taken sucking avian blood in late June (Bennett, 1960), but this may be for a second gonotrophic cycle. Simulium decorum Walker Simulitum decorum Walker, 1848, List Diptera, Brit. Mus. 1: 112 (female). Holotype. Female, British Museum, London, England. Type locality. St. Martin’s Falls, Albany River, Ontario, 1844 (G. Barnston). Ontario distribution. Kenora Dist. (Patricia Subdist.), June 20-26; Kenora Dist., June 16-29; Cochrane Dist., June 29; Timiskaming Dist., June 30; Nipissing Dist., May 20-Nov. 4; Renfrew Co., Aug. 25; Bruce Co., July 9-10; Muskoka Dist., May 20-July 27; Dufferin Co., July 30; Hasting Co., May 25-Aug. 3; Lanark Co., May 18-Aug. 8; Carleton Co., July 9-Oct. 5; Huron Co., Aug. 3-10; Middlesex Co., Aug. 8. 109 Biological notes Females of this multivoltine species usually ovipesit while settled on vegetation, wood, cement or rocks at the outlets of lakes or ponds, where the surface has a thin sheet of water flowing slowly over it, or is lightly sprayed or lapped by water (Davies and Peterson, 1956). In protected parts of the stream, eggs are often laid while the flying female taps her abdomen to the water surface. In southern Ontario, overwintering eggs hatch in late April. Larvae develop in streams ranging in width from less than 1 foot to more than 15 feet. Pupation occurs about mid-May with emergence occurring in the last half of May in warm years. Mating may occur a few minutes after emergence, while adults crawl about at the water’s edge, but gravid females may also mate with newly emerged males, just prior to oviposition (Davies and Peterson, 1956). Females of the first generation which emerge in late May, contain much stored nutrient, and eggs that are a third- to half-grown, but in mid-July the eggs in newly emerged females are more immature. Females have well-developed mouth- parts, but whether they require blood for the first gonotrophic cycle in Ontario is as yet unknown. However, females feed on humans, deer and horses as early as May 21, and on birds, when in vials inverted over the skin (Davies and Peterson, 1956). Wolfe and D. G. Peterson (1959) indi- cated that in Quebec, females of the first generation were gravid on emer- gence and oviposited within 48 hours without requiring a blood meal. There are two or more generations annually (Davies, 1950), and oviposi- tion may occur from May 20, into early October as judged by eggs col- lected on October 9 (Davies and Peterson, 1956). Simulium emarginatum, new species Female. A small, gray pollinose species, with almost entirely whitish hair. Length: body, 2.5-3.0 mm.; wing, 2.5-2.8 mm. Posterior surface of head, frons and clypeus gray pollinose. Hair on frons sparse, restricted to the dorsal one-half. Clypeus with sparse, recum- bent hair. Antenna dark, relatively long, with pale pubescence. Third seg- ment of maxillary palpus darker than remaining segments; sensory vesicle about one-half the length of the segment. Scutum gray pollinose, slightly paler at the margins; sparsely covered with short, recumbent white hair with a yellowish tinge. Scutellum with erect, white and brown hair. Postscutellum and pleuron gray pollinose, pleural membrane lighter. Postscutellum and katepisternum bare. Pleural tuft, and hair on the pronotum and proepisternum whitish. Precoxal bridge incomplete, with a small gap near proepisternum (some older individuals may show a tenuously complete bridge on one or, rarely, both sides). Legs brown, slightly darker distally; basal portion of leg with white hair, that on the basitarsus interspersed with some dark hair, remainder of the tar- sus with nearly all brown hair. Claw with a large, basal, thumb-like pro- jection. Hair on stem vein black, sometimes mixed with white; hair on base of costa white, remainder of costa, dorsal surface of radius and ven- tral surface of subcosta and radial sector with dark hair. Abdominal ter- gites grayish-brown, lightly pollinose; tergites rather snarsely covered with recumbent, white hair that is mixed with darker, longer hair on the last two tergites. Pleural membranes pale gray except for a darker spot at the base of each segment laterally (often obscured in the intersegmental folds) ; this spot is absent on segment one, smallest on segment two, but higher and extending to the tergite on the third and fourth segments, and is more obscure on distal segments. Lateral margins of segments 2-7 each with a patch of rather long, dense, white hair which is separated from the 110 sparser hair of tergites 2-4 by a bare, or nearly bare, membranous area, but is continuous with the sparsely haired regions of the remaining ter- gites. Venter of abdomen pale gray, each segment with a row of widely scat- tered small, white hairs. Genitalia as in Fig. 32. Terminal plate of genital fork densely sclero- tized, the posteromedial areas dark brown, the anteromedial angles, or tu- bercles, well-developed. Anal lobe with mixed white and dark hair; the membranous, ventral nipple located near the posterior margin. Male. General body colour blackish-brown with grayish-brown polli- nosity and brown hair. Posterior surface of head and clypeus dark brown, with grayish-brown pollinosity and brown hair. Antenna dark, with pale pubescence on the flagellum; scape and pedicel with dark hair. Palpus grayish pollinose, third segment darker; segments with brown hair, a few paler hairs pre- sent on last two segments; sensory vesicle of third segment small, about one-fourth the length of the segment. Scutum dull blackish-brown, margins faintly grayish-brown pollinose; with recumbent, shining brown hair. Humerus slightly lighter than scutum. Pleuron pale grayish-brown pollinose, paler and more shining than scu- tum; pleural tuft brown. Katepisternum bare. Legs brown; hair brown, rather long and dense, especially along dorsal edge of femur. Abdominal tergites greyish-brown pollinose in lateral view, duller and darker in posterior view; hair brown, long on basal scale, shorter and more erect on tergites 2-6, and recumbent on remaining tergites. Pleural mem- branes and sternites paler, gray pollinose, the latter with sparse, short, erect, brown hair. Genitalia as in Fig. 64. Basistyle brown. Dististyle darker brown, with black hair, moderately curved, uniformly tapering and terminating in a small spine. Body of ventral plate thin and flat, unusually wide and with a broadly concave, distal margin and a subparallel, convex, proximal mar- gin; most of central portion ventrally covered with pale, recumbent hair; basal arms short, slightly convergent. Paramere rectangular, about twice as long as broad, with a ventrally directed spine at the junction of para- meral arm; parameral arm lightly sclerotized at junction with paramere appearing as a separate, spine-like structure; parameral teeth numerous and well-developed. Median sclerite unforked, with concave lateral mar- gins. Dorsal sclerite wide and short, strap-like. Pupa. Respiratory organ about 2.5 mm. long, shorter than pupa; composed of four filaments in two petiolate pairs, the ventral petiole slightly longer and narrower than the dorsal petiole; filaments moderately divergent in a dorsoventral plane; the integument grayish-white, paler basally, rather smooth and shining. Holotype. Female, reared from a pupa collected May 5, 1959, from Sharpes Creek (also called Sparks Creek), where it crosses Highway No. 17, about one-half mile west of Rutherglen, Bonfield Twp., Nipissing Dis- trict, Ontaria, D. M. Davies and D. M. Wood. Allotype. Male, same data as holotype. Paratypes. Fifteen males and 45 females, same data as holotype. Types (No. 7994) and paratypes deposited in the Canadian National Col- lection. Paratypes deposited in the U.S. National Museum, McMaster Uni- versity, and British Museum. Ontario distribution. Nipissing Dist., May 2-June 28; Wellington Co., April 22-25; Wentworth Co., April 26-28. lil Comparison with related species. | This species is very similar to S. euwryadminiculum, from which the male is easily separated by the shape of the ventral plate, the posterior margin being broadly concave instead of straight. The female is almost indistinguishable from the female of S. euryadminiculum but is consis- tently smaller, and the terminal plates of the genital fork are more strongly sclerotized. The hair of the scutum also is yellowish in S. emargi- natum and white in S. euryadminiculum. Biological notes Females appear to oviposit in micro-bays of the stream, over fine sand kept moist by a thin sheet of water (Davies and Peterson, 1956, under the name S. euryadminiculum). Eggs laid in late May are in diapause at least until autumn, and possibly until early spring. Pupae collected near Fergus produced adults by April 22. Pupation occurred, at least, by the end of April in Algonquin Park (water temperature 40-50°F), with adults emer- ging by the first week of May and continuing into June. One female was netted on June 28, over the water, 20 feet from the shore of Lake Sasaje- wun, Algonquin Park. Newly emerged females have immature eggs and much stored nutrient. They also have well-developed mouthparts and bifid claws which suggests that they feed on the blood of birds. Simulium euryadminiculum Davies Simulium euryadminiculum Davies, 1949, Canad. Ent. 81: 45-49, Figs. 1-3, 4A-B, 5A-C, 6 (female, male, pupa). Holotype. Male, Type No. 5867, Canadian National Colection. Type locality. Costello Creek, Algonquin Park, Ontario, May 20, 1940 GRP. Tde):. Ontario distribution. Cochrane Dist., May 31; Nipissing Dist., April 19-June 21; Renfrew Co., April 22-May 5; Hastings Co., May 14; Carleton Co., May 18. Biological notes This species may lay its eggs freely into the water while in flight. The eggs which are laid in the spring, remain in diapause at least until autumn, but possibly until early spring. In the Baie Comeau region of Quebec, they are reported to overwinter as larvae (Wolfe and D. G. Peterson, 1959). Pupae are found in mid-April in Algonquin Park, and adult emergence begins in late April and continues until the end of May when water tem- peratures are between 50-60°F (Davies, 1950). Females with immature eggs and nectar-filled diverticula fly over the middle of lakes from the end of May until the end of June, or possibly until early August, but few — are netted over land (Davies and Peterson, 1957). Females have immature eggs and much stored nutrient on emergence, and with their well-develop- ed mouthparts and bifid claws are adapted to feed on avian blood. Al- though records of females feeding on birds have been reported (Davies and Peterson, 1956; Anderson, 1956), these reccrds are open to question because subsequent collections of flies commonly found feeding on white Pekin ducks at the same lake shore, proved to be S. congareenarum. How- ever, many females of S. ewryadminiculum engorged with blood were taken from a recently killed common loon (Gavia immer) on May 15, and more females were attracted to it sometime later after death. On the other hand, only engorged S. congareenarum females were taken from a white Pekin duck which was placed at the same site on the lakeshore. 112 Simulium excisum, new species Simulium (Husimulium) subexcisum Edwards, Twinn, 1936, Canad. Je ives... D, 14: 118-120. Female. A small, gray to grayish-brown species, with whitish hair. Length: body, 2.0-2.5 mm.; wing, 2.5-2.8 mm. Posterior surface of head, frons and clypeus gray pollinose, with whitish hair, that on frons and clypeus recumbent. Antenna dark gray, with pale pubescence: scape and pedicel with pale hair. Palpus grayish- brown; length of sensory vesicle of third segment about one-fourth the length of the segment. Scutum grey pollinose, paler on the humeri, with recumbent, white hair. Scutellum with long, erect, white hair mixed with a few darker hairs. Pleuron and postscutellum gray pollinose, concclorous with scutum. Pleural tuft and hair on pronotum and proepisternum white, erect. Basi- sternum connected to proepisternum by a precoxal bridge. Postscutellum and katepisternum bare. Costa, stem vein, dorsal surface of radius and ventral surface of subcosta and radial sector with dark hair. Legs brown, paler than thorax (especially in teneral specimens), with white hair basal- ly, and brown hair on the apex of the tibiae and tarsi. Abdomen with relatively dense, long, white hair (especially long on basal fringe) covering top and sides, and sparser aud shorter ventrally. Last two segments with a few dark hairs in addition to the white hair. Ground colour of tergites gray, paler on pleura and even paler on venter. Genitalia as in Fig. 29. Arms of genital fork slender; terminal plates triangular, strongly sclerotized along distal margin. Male. General body colour blackish-brown to grayish-brown pollinose, with brown hair. Posterior ‘surface of head, and clypeus dark brown with scant, grayish pollinosity and brown hair. Antenna uniformly dark; flagellum with recumbent, whitish pubescence; scape and pedicel with dark hair. Palpus grayish-brown pollinose, paler on fourth and fifth segments, with brown hair; sensory vesicle of third segment small, its length about one- fifth the length of the segment. Thorax uniformly grayish-brown pollinose. Hairy on pronotum and proepisternum brown. Scutum grayish-brown pollinose with a slight bluish cast, which is usually visible on the central portion even in direct view; with a wide, paler marginal band. Hair brown, short, recumbent and rather sparse. Scutellum dark, with long, erect, brown hair. Postscutellum bare, grayish-brown pollinose, subshining. Pleuron slightly paler than scutum; pleural tuft brown. Katepisternum bare. Legs uniformly brown, concolor- - ous with thorax (paler in teneral specimens); hair brown, with a few paler ones. Calcipala small; pedisulcus shallow. Abdominal tergites grayish-brown pollinose with a bluish cast in lateral view, dull dark brown in posterior view; hair brown, dense and long, shorter and sparser on the last three segments. Pleural membranes and sternites paler, gray pollinose, the latter with sparse, moderately long, erect dark hair. Genitalia as in Fig. 68. Basistyle and dististyle grayish-brown polli- nose, with dark hair. Dististyle moderately curved, uniformly tapering, with a small,apical spine. Body of ventral plate triangular, covered with pale, recumbent hair; ventrally recurved lip relatively weak; basal arms rather short, slightly curved inwardly. Paramere broadest at base, tapering dis- tally te the slender parameral arm, which bears 5-6 relatively small and weakly sclerotized teeth. Median sclerite weak, broadest at the base, with a small, forked tip. Dorsal sclerite short, wide, strap-like. 113 Pupa. Respiratory organ about 3.0 mm. long, slightly longer than pupa; consisting of six slender filaments in three pairs; petiole of dorsal pair directed dorsally at right angles to the other two pairs, its point of attachment constricted and flexible; petioles of remaining filaments di- verging in a horizontal plane. Cocoon slipper-shaped, with a long anterior process that has thickened margins and a more transnarent, central strip. Holotype. Female, reared from a pupa collected May 5, 1961, from a roadside ditch one and one-half miles west of Stanley Corners (C.P.H. #1 of Twinn, 1936), Goulbourn Twp., Carleton Co., Ontario, D. M. Wood and E. Bond. 7 Allotype. Male, same data as holotype. | Paratypes. Twenty-five males and 40 females, same data as holotype. Types (No. 7993) and paratypes deposited in the Canadian National Col- lection. Paratypes deposited in the U.S. National Museum, British Mu- seum and McMaster University. Ontario distribution. Kenora Dist. (Patricia Subdist.). June 18; Ren- frew Co., May 3-20; Muskoka Dist., May 2-10; Ontario Co., May 1-25; Frontenac Co., May 6; Lanark Co., May 18; Carleton Co., May 5-25; Wel- lington Co., April 26; Wentworth Co., April 25-May 8. Comparison with related species This species appears to be closely related to S. rivuli, S. innocens and S. congareenarum. The males of S. excisum are most readily distinguished from the males of the other species by the small size of the teeth on the parameral arms and by the more abundant pollinosity of the scutum. The female most closely resembles some specimens of S. congareenarum but may be most reliably distinguished by differences of the terminal plates of the genital fork. The above four species approach rather closely the genus Cnephia, but in this genus the second basal cell is complete and distinct. Biological notes | Twinn (1936) collected pupae of this species (under the name S. (Eusimulium) subexcisum Edwards) on May 8, 1935, at the type locality of S. excisum, near Stanley Corners (C.P.H. #1 of Twinn) from which he reared two males and one female. | This species probably overwinters in the egg stage. Young larvae occur in mid-April at water temperatures of about 45°F. Adult emergence begins in late April (water temperature 50-55°F) and continues into late May in southern Ontario. Three exuviae were found on June 18, at Big Trout Lake, in the Patricia sub-district (water temperature 58°F). The records of this species (under the name of S. subexcisum) feeding on birds (Bennett, 1960) need further confirmation. Females have well-developed mouthparts and bifid claws, but at emergence they have moderate to large amounts of stored nutrient, and eggs a third- to a half-grown. They may be autogenous for the first gonotrophic cycle. Simulium fibrinflatum Twinn Simulium (Simulium) fibrinflatum Twinn, 1936, Canad. J. Res., D, 14: 141-142, Fig. 138A, 1-5 (female, male, pupa). Holotype. Male, Type No. 4128, Canadian National Collection. Type locality. Remic Rapids of the Ottawa River, at Cunningham Island, Ottawa, Ontario, emerged from pupa August 17, 1936 (C. R. Twinn). Ontario distribution. Carleton Co., July 24-Aug. 17. 114 Biological notes In the Remic Rapids of the Ottawa River at OHeee Wine (1936) found no pupae on July 3, but some pupae and many exuviae were present on July 22 (water temperature 76°F). On August 16, he found this spe- cies in large numbers, with only an occasional pupae of S. jenningsi and S. venustum. Many larvae were present on August 29, but by September 13 (water temperature 64°F) only a rare pupa was found, and by September 30 (water temperature 56°F) none at all. Twinn (1936) described the location as “a narrow channel dividing the east end of the [Cunningham] island from a tiny islet through which the shallow water was rushing at a speed of about five feet per second, over a shale-rock bottom’. Pupae and exuviae were mainly attached to the submerged branches and leaves of sweet gale, an abundant shrub along the margins of the channel. There are probably two or more generations annually. Pupae have been collected as early as the end of May in Virginia (Stone and Jamnback, 1955). tSimulium furculatum (Shewell) Kusimulium furculatum Shewell, 1952, Canad. Ent. 84: 40-42, Fig. 4 A-G (female, male, pupa). Holotype. Male, Type No. 5990, Canadian National Collection. Type locality. Goose River, Churchill, Manitoba, July 9, 1947 (reared) (C. R. Twinn). Ontario distribution. Kenora Dist. (Patricia Subdist.), June 22-27; Hastings Co., May 22-June 38. Biological notes This species was first found i in Ontario in the Crow River, near Mar- mora by J. R. Vockeroth and G. E. Shewell who reared adults from May 22 to June 3, 1952. Our records show larvae, pupae and reared adults in late May of 1959 and 1960, from a fast chute at the dam on the Crow River. At Big Trout lake, Patricia Subdistrict, larvae were collected on June 22, 1961, and adults were reared, and one netted, from June 22-26. At Churchill, Manitoba, larvae were taken on June 14, and pupae from June 18 to August 6 (Hocking and Pickering, 1954), and adults were reared from June 26 until July 22 (Shewell, 1952). Collections of adults from emergence cages were made from late June to the end of July, with a few individuals being trapped in mid-August (Ide et al., unpublished manuscript). Mating swarms, composed largely of males, occurred at Churchill from June 25-July 23, from which mating pairs were collected (Hocking and Pickering, 1954). Simulium goulding: Stone Simulium (Eusimulium) gouldingi Stone, 1952, Proc. ent. Soc. Wash. 54: 90-91 (female, male, pupa). Holotype. Female, Cat. No. 61192, U.S. National Museum. Type locality. Route 115, 14.5 miles west of Wiikes Barre, Pennsyl- vania, June 5, 1948 (reared) CA Stone). Ontario distribution. Nipissing Dist., June 2-Aug. 4; Muskoka Dist., May 19-28; Ontario Co., June 6. Biological notes This uninivoltine species appears to overwinter as ezgs which begin to hatch in early May. Larvae are found from May until! the latter part of July in | shallow streams, 1-4 feet wide, just at the edge of woods. Pu- Ih) a pation begins about mid-May (water temperature 50-60°F) and adults are on the wing at least until August 4. Females have well-developed mouthparts and bifid claws, and on emergence have undeveloped eggs and only a little stored nutrient. They are presumably ornithophilic. Simulium impar, new species Female. A minute, gray to grayish- brown species, with whitish hair. Length: body, about 2. 0 mm.; wing, 2.2-2.5 mm. Posterior surface of head, clypeus and frons gray pollinose. Hair on frons and ventral portion of clypeus whitish, recumbent. Flagellum of antenna dark grayish-brown; scape and pedicel pale yellowish-brown; segments all with whitish pubescence. Palpus dark gray pollinose, third segment almost black, hair brown; length of sensory vesicle of third seg- ment about one-half the length of the segment. Scutum gray pollinose with recumbent, white hair with a yellowish tinge. Humeri yellowish-brown, with a central spot of gray pollen and whitish hair. Scutellum with long, erect, brown and white hair mixed. Pleuron and scutellum brown to yellowish-brown, ligntly brown pollinese. Pleural tuft and hair on pronotum and proepisternum concolorous with that of scutum. Scutellum and katepisternum bare. Hair of costa brown except for a few longer, paler ones basal to the humeral cross-vein; hair of stem vein, dorsal surface of radius and ventral surfaces of subcosta and radial sector brown. Legs paler than thorax (all the available speci- mens appear teneral and the integument probably darkens with age) ex- cept for the coxae, distal ends of femora and tibiae, and all of the tarsi which are gray. Hair on legs whitish except mixed brown and white on basitarsi and brown on other tarsal segments. Claw with a large, basal, thumb-like projection. Abdominal tergites pale grayish-brown, slightly darker than the re- mainder of abdomen. Basal fringe white, relatively short. Hair on remain- der of abdomen short, mostly brown and scattered, leaving most of the integument exposed. Genitalia as in Fig. 40. Arms of genital fork narrow at point of bi- furcation, with little infilling; arms long, the terminal plates rather wide- ly separated. Anteromedial corners of anal lobes concave when viewed ventrally, the median margins in this region relatively well defined. Male. Similar in size to female. General body colour brown to pale grayish-brown pollinose, with pale gold hair on scutum. Posterior surface of head and clypeus gray-brown pollinose with mixed dark and pale hairs. Antenna grayish-brown with pale pubescence. Palpus uniformly pale grayish-brown pollinose, with light and dark hair; sensory vesicle of third segment minute, about one-sixth the length of the segment. Thorax dull brown on scutum, pollinose on margins. Pleuron, scu- tellum and postscutellum pale grayish-brown pollinose. Hair of scutum pale gold, short and recumbent; hair on pronotum and proepisternum longer, golden in colour. Pleural tuft pale. Postscutellum and katepisternum bare. Legs rather pale (all available specimens appear teneral) ; coxae of all legs with mixed pale and dark hair anteriorly, and darker hair laterally; hair on remainder of legs brown with interspersed paler ones. Calcipala and pedisculus well developed. Abdominal tergites dull brown, somewhat grayish pollinose in lateral view, second tergite more pollinose than others; hair brown, erect, with a few recumbent, paler hairs distally. Pleural ‘membranes and sternites paler, grayish- brown pollinose. Hair on sternites brown, erect and sparse. 116 Genitalia as in Fig. 76. Basistyle and dististyle brown, with dark hair. Dististyle enlarged apically, with a flattened, triangular, medially directed flange bearing a small spine at its apex. Body of ventral plate broadly V- shaped in terminal view, the lip moderately prominent; basal arms curved medially. Paramere broad basally, narrowing distally and bearing a long, dorsally recurved spine at its distal end. Median sclerite forked distally to one-half its length. Dorsal sclerite about as broad at base as long, taper- ing distally to a blunt point. Pupa. Respiratory organ about 2.0 mm. long, nearly as long as pupa, consisting of four filaments in two petiolate pairs; petiole of ventral pair narrower and five or more times as long as the short petiole of the dorsal pair. Filaments moderately divergent in vertical plane; integument pale gray, rugose, sub-shining. Cocoon slipper-shaped, with thickened anterior margin. Holotype. Female, reared from a pupa collected June 25, 1959, from a small stream crossing the Laurentian Point Road and flowing into the Ottawa River about three miles west of Point Alexander, Rolph Twp., Renfrew Co., Ontario, D. M. Davies and D. M. Wood. Allotype. Male, same data as holotype. Paratypes. Fifteen males and 35 females, same data as holotype. Types (No. 8012) and paratypes deposited in the Canadian National Collection. Paratypes deposited in the U.S. National Museum, British Museum and McMaster University. Comparison with related species This species is similar to and probably closely related to S. quebecense. The male is similar to this species but differences in the ventral plate appear to be constant. The genital fork of the female, however, is unlike that in the female of S. quebecense. The respiratory filaments of the pupa are distinctive. Biological notes This species was found in a small stream, 2-4 feet wide, whereas S. quebecense usually occurs in rivers over 10 feet wide. This species is pre- sumed to be univoltine. The larvae hatch in May. On June 25, larvae, pupae and exuviae were found in a stream near Point Alexander. Females have well-developed mouthparts and bifid claws, and on emergence have im- mature eggs and only a small amount of stored nutrient. This suggests that S. impar. is ornithophilic. Simulium innocens (Shewell) Husimulium innocens Shewell, 1952, Canad. Ent. 84: 38-39, Fig. 3A-G (female, male, pupa). Holotype. Female, Type No. 5989, Canadian National Collection. Type locality. Bell’s Corners, Ontario. Pupa collected June 2; adult emerged June 6, 1950 (G. E. Shewell). Ontario distribution. Renfrew Co., May 20-21; Muskoka Dist., May 12-31; Bruce Co., June 8; Frontenac Co., May 25-June 9; Carleton Co., May 10-June 10. Biological notes Present evidence indicates that this species in univoltine. The eggs are probably laid in late spring and remain in diapause until late April or early May of the following year. Larvae are often found on submerged, trailing grass and reeds in small, shallow, often temporary streams (au- 117 thors’ data; Shewell, 1952). Pupation occurs most frequently on vegetation, near the stream bottom, sometimes on Fontinalis moss (Shewell, 1952). Pupation may begin in early May (water temperature 55-65°F) and con- tinue into June. Females have mouthparts developed for bloodsucking and have immature eggs and some stored nutrient just after emergence. These features and the presence of bifid claws suggests that they feed on avian blood. Simulium jenningsi Malloch Simulium jenningsi Malloch, 1914, U.S. Dep. Agric., Bur. Ent., Tech. Ser. 26: 41-48, Plate 3, Fig. 1; Plate 5, Fig. 12 (female, male, pupa, larva). Holotype. Female, Cat. No. 15412, U.S. National Museum. Type locality. Plummers Island, Maryland, July 8, 1904. Ontario distribution. Thunder Bay Dist., June 14-30; Algoma Dist., June 26-July 23; Parry Sound Dist., June 7-23; Nipissing Dist., April 22- Sept.; Bruce Co., Aug. 17-Sept. 7; Simcoe Co., June 28; Hastings Co., May 30- Sept. 8; Lanark Co., June 13; Carleton Co., June 8-Oct. 23; Pres- cott Co., July 25; Perth Co., Aug. 17. Biological notes Jobbins-Pomeroy (1916) reported that females oviposit along the moist edge of a partly submerged grass blade trailing in the water, but that the egg masses were smaller than those of S. venustum. However, Under- hill (1944), during a careful study in Virginia, was unable to find any ege masses of S. jenningsi which suggests that this multivoltine species may possibly deposit its eggs into the water while in flight. Underhill, and Anderson and Dicke (1960) considered the egg to be the overwintering stage. Eggs probably hatch in late April or early May in southern Ontario, because pupae and exuviae were found at the end of May (water tempera- ture 69°F). Larvae are found in clear rivers over 20 feet in width (authors’ data; Twinn, 1936; Underhill, 1944—the last two authors using the name S. nigroparvum). Twinn (1936) visited the Remic rapids of the Ottawa River two or three times a month from iate April until the end of September and found fresh pupae first on June 6 (water tempera- ture 63°F), which appears to substantiate the hypothesis that the winter is passed in the egg stage. Pupae appeared here again in early July, and by July 22 (water temperature 76°F) exuviae predominated suggesting the end of the second generation. Although further generations may have occurred, there were only few pupae present from August 2-29, and, after a 40 minute search, only one was found on September 13. Another year, however, Twinn (1936) found numerous pupae here on September 16. The female has well-developed mouthparts and on emergence contains undevel- oped eggs and much stored nutrient. In Virginia, females of this species attacked turkeys, but only around the sparsely feathered head and neck (Underhill, 1944) presumably because the flies lack the bifid claws which Shewell (1955) suggested facilitate crawling through the feathers. A few females were collected from horses, cattle and rarely from man (Underhill, 1944), but Malloch (1914) reported that in both North and South Carolina they severely bit horses, especially in the ears. This species is, at times, a local pest of man in parts of Ontario and central Quebec. Simulium latipes (Meigen) Atractocera latipes Meigen, 1804, Klassif, Beschr. Europaischen Zweiflig. Insekten 1: 96 (male). Holotype. Male (location not known to the authors). 118 Type locality. Not known to the authors. Ontario distribution. Kenora Dist. (Patricia Subdist.), June 18-27; Kenora Dist., June 15-29; Thunder Bay Dist., June 13-July 1; Cochrane Dist., June 26-29; Algoma Dist., June 13-July 1; Manitoulin Dist., June 12; Nipissing Dist., May 13-Aug. 3; Renfrew Co., May 20-June 25; Mus- koka Dist., May 10-July 4; Bruce Co., June 8-July 10; Ontario Co., May 18-31; Hasting Co., May 30-June 19; Frontenac Co., May 22; Carleton Co., May 14-June 1; Wellington Co., May 17; Peel Co., May 18-30; Wentworth Co., May 18. Biological notes One or more members of this species complex may be univoltine but, at the moment, the complex as a whole has two or more generations an- nually. Eggs appear to overwinter (authors’ data; Stone and Jamnback, 1955) and probably hatch in mid-April in southern_Outario because small larvae were collected in early May (water temperature 60°F). These pro- duced adults in mid- to late May. At lower water temperatures, 45-50°F, larvae may not reach maturity until early June. This species occurs in a variety of habitats; from the slower, more shallow parts of rivers to nar- row, shallow, temporary streams. Pupation usually occurs under leaves, wood chips, pebbles and stones, sheltered from strong currents. Larvae and pupae occur through June and July into early August, suggesting that at least three generations occur in southern Ontario. In northern Ontario, at water temperatures of 54-58°F, larvae were found on June 18. In streams with a water temperature of 52°F larvae were found as late as June 25, but in those with a temperature of 58-60°F, pupae appeared by June 22. Females have bifid claws and mouthparts well adapted for suck- ing blood. On emergence the females contain undeveloped eggs and various amounts of stored nutrient. They have been collected feeding on birds from late May to early July (authcrs’ data; Davies and Peterson, 1956; Bennett, 1960). Simulium longistylatum Shewell Simulium (Hagenomyia) longistylatum Shewell, 1959, Canad. Ent. 91: 84, 86-87, Figs. 1-7 (female, male, pupa, larva). Holotype. Male No. 6695, Canadian National Collection. . Type locality. Outardes River, Baie Comeau, Quebec, July 21, 1955 (L. S. Wolfe). | Ontario distribution. Kenora Dist. (Patricia Subdist.), June 21; Thun- der Bay Dist., June 14; Algoma Dist., Aug. 29; Parry Sound Dist., Oct. 28; Nipissing Dist., July 8; Muskoka Dist., June 6-Oct. 10; Simcoe Co., Aug. Ze2A Biological notes This multivoltine species appears to overwinter in the egg stage. Sub- mature larvae, presumably of the first generation, were collected on May 20, and adults on June 15. In other years, adults were netted as early as June 6, and larvae and pupae were still present on Qctober 9, in the Ox- tongue River and Muskoka River in the Muskoka District. This species inhabits the fastest water of waterfalls where larvae and pupae are present in dense masses having a moss-like appearance. S. pictipes shares the same habitats but in much lower numbers, and S. tuberosum occurs in moderate numbers just below these falls. Larvae of S. longistylatum have unusually strong salivary ‘gum’ and they have been observed crawling up a rock 119 face against strong current. Males form large swarms over, or just below, the lip of the falls (Davies and Peterson, 1956, as S. pictipes) and females are usually netted close to the face of the falls. Mating may occur as males flying upstream meet females above the falls. Females on emergence, have undeveloped eggs and a large amount of stored nutrient. Whether they are autogenous for the first ovarian cycle is unknown, but they are known to bite humans (Davies and Peterson, 1956, under the name of S. pictipes), although this is a rare occurrence. Females land and oviposit on water- lapped rocks at the lip of the falls, and form rings of 8-16 eggs (Davies and Peterson, 1956, as S. pictipes). Oviposition, presumably of this species, occurred from June 26 to early October. Simulium parnassum Malloch Simulium parnassum Malloch, 1914, U.S. Dep. Agric., Bur. Ent., Tech. Ser. 26: 36-37, Plate 2, Fig. 8; Plate 5, Fig. 11 (female). Holotype. Female, Cat. No. 15409, U.S. National Museum. Type locality. Red Hill, Moultonburgh, New Hampshire, Aug. 5, (H. G. Dyar). Ontario distribution. Nipissing Dist., June 21-Aug. 15: Muskoka Dist., June 23-July 6; Hastings Co., Aug. 2. Biological notes This species is univoltine. The somewhat bean-shaped eggs are laid from late June to mid-August and overwinter. One breeding site has been found in Ontario, at Cedar Lake on the northern side of Algonquin Park. This stream, although coming from a warm beaver pond, is cooled by springs and seepages in passing through dense hemlock - yellow birch - beech - maple woods. It is 2-3 feet wide, and flows over large, angular rocks, rotting sticks, and vegetation. Larvae and pupae were found on August 4-6, in the swiftest microfalls at 65°F. Newly emerged females have undeveloped eggs and moderate to large amounts of stored nutrient. Fe- males are troublesome to humans in northern and southern Algonquin Park. They appear in mid- to late June, reaching their peak after the peak of S. venustum and may continue to attack humans in some moist years to mid-, or even late August. About seven days after a blood meal, they have mature eggs (Davies and Peterson, 1956). Simulium pictipes Hagen Simulium pictipes Hagen, 1879, Proc. Bost. Soc. nat. Hist. 20: 305- 307 (female, male, pupa, larva). Cotypes. ? Four females, one male, type No. 12532, Museum of Com- parative Zoology, Harvard College. Type locality. Ausable River, Adirondack Mountains, New York, August (R. P. Edes and H. P. Bowditch). Ontario distribution. Kenora Dist., July 25; Nipissing Dist., June 15- 29; Renfrew Co., July 25; Muskoka Dist., June 19-Julv 8; Haliburton Dist., July 1-Sept. 21; Lanark Co., Aug. 7-27; Carleton Co., June 21-Aus. 7; Haldimand Co., May 31. é Biological notes This species has four, or possibly five generations in New York, and the winter is passed in the larval stage (Smart, 1934). In the Muskoka District of Ontario, it breeds in the fastest parts of waterfalls, but is great- 120 ly outnumbered by S. longistylatum. Adults were reared from pupae col- lected at Marshs Falls, Oxtongue River, from June 26 to July 8, and fresh exuviae were collected on August 7. One reared female had undeveloped eggs and less stored nutrient than reared females cf S. longistylatwm. Twinn (1936) reared adults from pupae on August 2, at Carleton Place. There are records of it feeding on horses (Malloch, 1914) and a mule (Jobbins-Pomeroy, 1916) and even on a human (Smart, 1934). tSimulium pugetense. (Dyar and Shannon) Eusimulium pugetense Dyar and Shannon, 1927, Proc. U.S. nat. Mus. 69(10) : 23, Plate 7, Figs. 121-123 (male). Holotype. Male, Cat. No. 28338, U.S. National Museum. Type locality. Seattle, Washington (C. V. Piper). Ontario distribution. Peel Co., March 28-April 16. Biological notes The first authentic Ontario records of this species were collected by K. H. Rothfels from the outlet of a spring-fed pond which flowed over angular rocks and stones interspersed with decaying sticks, near Cataract. The first reared adults were obtained from pupae collected here by the authors on April 6, 1957 and April 7, 1958. Immatures of this univoltine Species were completely gone from the stream by late July. The eggs, which presumably are laid in the spring, are in diapause during the summer. The species overwinters as larvae, and third stage larvae are present in the stream in late December. Pupation begins in late March, at a water temperature of about 40°F, and reaches a maximum in the second week of April. Females have bifid claws and mouthparts suitabie for bloodsucking ; when newly emerged, they contain immature eggs and some stored nu- trient. {Simulium quebecense Twinn Simuhum (Husimulium). quebecense Twinn, 1936, Canad. J. Res., D, 14: 117-118, Fig. 6B, 1-5 (female, male, pupa). 7 Holotype. Female, Type No. 4124, Canadian National Collection. Type locality. Blanche River, about five miles south of Perkins Mills, Quebec. Pupa collected May 22; adult emerged May 26, 1935 (C. R. Twinn). Ontario distribution. We Bay Dist., June 13-July 1; Nipissing Dist., May 17-June 10. Biological notes Simulium quebecense probably cviposits while in flight because on June 10, a female, with mature eggs, was observed flying close to, and oc- casionally landing on, silt that was lapped by a thin sheet of water in a microbay of the North Madawaska River (Davies and Peterson, 1956, under the name of S. croxtoni). This species appears to be univoltine with the overwintering eggs probably hatching in May in southern Ontario. Larvae are found in rivers over 15 feet wide, attached to logs and sticks held at an angle in the stream, or to partly submerged twigs or trunks of small and large shrubs. The North Madawaska River, near Lake Sasaje- wun, Algonquin Park, is the only site where this species has been found in numbers in southern Ontario. Pupae, from which adults were reared, occurred on May 17, and in another year pupae were collected here on June 8 (water temperature 64°F). This agrees with records from the Blanche River, Quebec, just north of Ottawa, in which submature larvae were found by the authors on May 11 (water temperature 52°F), and 121 pupae on May 22 (authors’ data; Twinn, 1936). On the other hand, two males emerged on June 10, from a cool, shallow, bog-ied stream, four feet w.de, in Algonquin Park. In Stillwater Creek, two miles west of Nipigon, in central Ontario, larvae and pupae were collected on June 13 (water tem- perature 56°F), but on July 1, mainly pupae were collected (water tem- perature averaging 60°F). Newly emerged females have undeveloped eggs and little stored nutrient and their well-developed mouthparts and bifid claws adapt them for feeding on avian blood. Females were collected feed- ing on ruffed grouse and probably attack other birds as well. Simulium rivult Twinn Simulium (Husimulium) rivuli Twinn, 1936, Canad. J. Res., D. 14: 120-121, Fig. 6D, 1-3 (male, pupa). Holotype. Male, Type No. 4125, Canadian National Collection. Type locality. Small stream near Carleton Place [at eee ee Ontario. Pupa collected May 8; adult emerged May 13, 1935 (C. R. Twinn). Female. A small to minute, gray species, with pale vellow hair and yellow legs. Length: body, 1.8-2.0 mm.; wing, 2.0-2.3 mm. Head gray pollinose, with pale yellow hair covering frons and most of clypeus. Antenna dark gray, with pale pubescence. Paipus dark gray, with pale hair; length of sensory vesicle about one-fourth the length of the seoment. Scutum gray pollinose, paler on humeri, with recumbent, pale yellow hair. Pleuron gray pollinose. Scutellum and katepisternum bare. Fore coxa yellow, lightly gray pollincse basally, but as a whole contrasting with the dark gray of the pleuron. Mid- and hind coxae gray pollinose; trochanters, basal five-sixths of femora and central portion of tibiae pale yellow to. orangish-yellow, remaining portions gray to dark gray on last three seg- ments of tarsi. Hair on legs pale yellow basally, mixed with brown hair on basitarsus and entirely brown on remainder of tarsi. Calcipala small; pedisulcus shallow. Claw with a large, thumb-like basal projection. Abdominal tergites grayish-brown, lightly pollinose, remainder of ab- domen yellowish-brown; hair pale yellow, relatively long, moderately dense and evenly distributed on dorsal side, sparser ventrally, with a few longer, brown hairs on last two segments. Genitalia as in Fig. 31. Arms of genital fork narrow at point of bifur- cation, without infilling. Terminal plates lacking extensive, or deeply sclero- tized areas. Ontario distribution. Nipissing Dist., May 2-June 15; Renfrew Co., May 8; Muskoka Dist., May 1-18; Frontenac Co., May 6; Carletong@o- May 8. Biological notes Half-grown larvae were collected in mid- April in southern Ontario (water temperature 47-49°F). Pupation occurs in late April or early May, with emergence continuing until early June. Twinn (1936) first collected a pupa of this species on May 8, at Stanley Corners (CPH-1 of Twinn, | 1936). Females contain immature eggs and some stored nutrient on emer- gence. Their well-developed mouthparts and bifid claws suggest that they are ornithophilic. Simulium rugglesi Nicholson and Mickel Simulium rugglesi Nicholson and Mickel, 1950, Tech. Bull. Univ. Minn. agric. Exp. Sta. 192: 60-61, Fig. 23A-B (female). 122 Holotype. Female, University of Minnesota. Type locality. Todd Co., Minnesota, June 24, 1937 (on geese). Ontario distribution. Kenora Dist. (Patricia Subdist.), July 14; Coch- rane Dist.; Nipissing Dist., June 1-July 6; Muskoka Dist., June 15; Carleton Co., July 9. Biological notes The overwintering eggs hatch in the spring. The first Ontario breeding site of this species was found in 1961, in the North Madawaska River, below Lake Sasajewun, Algonquin Park. The larvae were scattered in re- gions of moderate current in the river which is 10-30 feet wide. They were attached to submerged, trailing grass, or on submerged logs which were positioned above a silty bottom. They were outnumbered by S. venustum larvae by a ratio of 9 : 1. Pupation began at the end of May, 1961. Females begin to feed on ducks at the edge of Lake Sasajewun, on about May 26 (Davies and Peterson, 1956), but are usually more abundant from June 11- 238, and may continue to feed into July (Bennett, 1960). They feed earlier in the evening than other ornithophilic species, i.e., from 6-8 p.m. (E.S.T.) (Bennett, 1960). Mating and oviposition have yet to be observed, although J. W. Leonard (1955, pers. com.) saw them swarming in June just at dark, 6-10 feet above the Pere Marquette River, Michigan; they emitted an audi- ble hum. Females, with immature eggs and nectar-filled crops, were collect- ed from a swarm over the lip of Marshs Falls, Oxtongue River, in mid- afternoon of June 15, 1955 (Davies and Peterson, 1956). Simulium tuberosum (Lundstrom) Melusina tuberosa Lundstrom, 1911, Acta Soc. Fauna Flora fenn. 34: 14-15, Fig. 10 (male). Holotype. Male (location not known to the authors). Type locality. Probably Enontekis (Enontekio), Finnish Lapland, Finland. Ontario distribution. Kenora Dist. (Patricia Subdist.), June 20-27; Kenora Dist., June 29; Thunder Bay Dist., June 13-July 1; Cochrane Dist., June 27-29; Algoma Dist., July 1; Timiskaming Dist., June 30; Nipissing Dist., May 21-Aug. 5; Renfrew Co., May 28-June 25; Muskoka Dist., May 26-Oct. 9; Bruce Co., July 9-10; Grey Co., June 18; Hastings Co., May 23- - Sept. 8; Lanark Co., May 18; Carleton Co., May 14-Oct. 18; Leeds Co., Sept. 13; Grenville Co., May 9; Halton Co., Oct. 18; York Co., June 21; Wentworth Co., May 18-Oct. 22; Norfolk Co., May 18-July 5. Biological notes This species is a complex of two or more undescribed forms in On- tario, which are probably distinct from the Palaearctic form. Wolfe and D. G. Peterson (1959) observed that oviposition occurred near the shore of a lake just above its outlet. Females alighted on the surface of calm water between stones and, at once, each deposited 10-20 eggs which slowly sank to the bottom. The flies then flew around close to the water surface before settling to oviposit again. Females did not lay eggs while in flight. This species has at least three generations annually and overwinters in the egg stage (authors’ data; Stone and Jamnback, 1955). Eggs of the first gen- eration hatch in May, but later than those of S. venustum in the same stream. The larvae, although sharing the same habitat as those of S. venustum, are more common in permanent streams that are a little cooler and swifter. Adult. emergence begins in late May to early June and con- tinues in some streams throughout the summer. Adults were reared from pupae collected as late as October 9. Newly emerged females contain a mod- 123 erate amount of stored nutrient and undeveloped egg's, and their mouth- parts are well-adapted for bloodsucking. Simulium tuberosum attacks hu- mans, horses and domestic animals (DeFoliart, 1951; Jamnback, 1952; Hocking and Richards, 1952; Wolfe and D. G. Peterson, 1959), but Stone and Jamnback (1955) suggest that only the first generation attacks hu- mans. Simulium venustum Say Simulium venustum Say, 1823, J. Acad. nat. Sci. Phila. 3: 28-29 (fe- male, male). Holotype. Female, type probably lost. Type locality. Shippingsport, Ohio, collection date was between May 5 and June 9. Ontario distribution. Kenora Dist. (Patricia Subdist.), June 18-29; Kenora Dist., June 15-29; Thunder Bay Dist., June 13-July 1; Cochrane Dist., May-Oct.; Algoma Dist., June 13-July 1; Timiskaming Dist., June 30; Manitoulin Dist., June 12-Aug. 5; Parry Sound Dist., June 19; Nipissing Dist., May 13-Oct. 15; Renfrew Co., May 28-June 25; Muskoka Dist., May 12-Aug. 3; Bruce Co., June 8-Sept. 7; Grey Co., June 18-Aug. 22; Dufferin Co., May 14-24; Simcoe Co., May 28-Aug. 21; Ontario Co., May 18-Aug. 18; Hastings Co., May 16-July 30; Frontenac Co., May 22-June 15; Lanark Co., May 7-18; Carleton Co., May 2-Sept. 18; Grenville Co., May 19; Huron Co., Aug. 3; Waterloo Co., Sept. 9; Wellington Co., May 3-June 24; Halton Co., July 29; Peel Co., May 14-81; York Co., May 4-Aug.16; Wentworth Co., May 3- June 24e Norfolk Co., May 18-June 6; Haldimand Co., May 31 (exuviae). Biological notes Females lay eggs in mats, often several layers deep, on vegetation at, or just below, the water surface. They appear to oviposit on green, glab- rous surfaces, such as the trailing leaves of cattails, reeds and grasses (Davies and Peterson, 1956). At no time were females observed to deposit eggs on wood or stone, but they may lay eggs by tapping the water surface while in flight, if trailing vegetation is lacking. Although generation con- tinue as long as the season permits, overwintering, in Algonquin Park at least, occurs in the egg stage (Davies, 1950). Larvae hatch in mid- to late April in extreme southern Ontario with adults emerging in early May. In the region of Algonquin Park (water temperatures 40-45°F) larvae hatch in early May and adult emergence occurs in late May or early June (au- thors’ data; Davies, 1950). In the latter part of July in northern Ontario only small larvae occurred in small streams, but pupae and exuviae oc- curred in larger streams with a higher average temperature. Larvae in- habit a wide variety of streams but are more common in large, permanent streams with shallow rapids, especially near the outlets of lakes. They may be found on any surface to which they can firmly attach themselves. Newly emerged females contain undeveloped eggs and little stored nutrient. About two days after emergence, they feed avidly on the blcod of mammals, in- cluding cattle (Teskey, 1960), and to a lesser extent they attack the sparsely feathered heads of adult birds or their semi-naked nestlings (Davies and Peterson, 1956). This species, because of its numbers and its persistence in attacking humans, is the most serious simuliid pest in Ontario. Females begin bloodsucking on about May 1, in extreme southern Ontario, but not until the latter part of May in Algonquin Park. In the Park, bloodsucking may continue throughout June and even to mid-July. Thereafter the dry 124 summer conditions reduce the numbers markedly. In early autumn another period of bloodsucking may occur (Davies and Peterson, 1956). At Moos- onee this species attacked persistently in late June. Simulium verecundum Stone and Jamnback Simultum (Simulium) verecundum Stone and Jamnback, 1955, Bull. N.Y. State Mus. 349: 83-84, Plate 7, Fig. 25; Plate 10, Fig. 41 (female, male, pupa, larva). Holotype. Male, Cat. No. 62361, U.S. National Museum. Type locality. Monroe Co., Pennsylvania, June 4, 1948 (reared) (A. Stone). Ontario distribution. Kenora Dist. (Patricia Subdist.), June 20-29; Thunder Bay Dist., June 13; Cochrane Dist., June 26-29; Nipissing Dist., June 24-July 16; Muskoka Dist., May 26; Hasting Co., June 19-July 3; Lanark Co., May 18; Carleton Co., June 13; Grenville Co., May 12; Nor- folk Co., May 18. Biological notes This species probably overwinters in the egg stage. The larvae may hatch in late April or early May in southern Ontario because adults have been taken a little after the middle of May. When compared to S. venus- tum, this species appears to be restricted generally to larger streams, those over ten feet wide, although it has been taken from a narrower stream that drained a pond in Algonquin Park. In central and northern Ontario, all stages, except eggs, have been collected during June. Stone and Jamn- back (1955) suggested that there were two or three generations annually and that it does not annoy humans. 3 Simulium vittatum Zetterstedt ? Simulia vittata Zetterstedt, 1838. Insecta Lapponica Descripta, page 803 (female). Holotype. A single female from Greenland, presumably the holotype, is in the Zetterstedt collection at the University of Lund, Lund, Sweden. Type locality. Greenland. Ontario distribution. Kenora Dist. (Patricia Subdist.), June 28; Ken- ora Dist., June 16-29; Thunder Bay Dist., June 30-July 1; Algoma Dist., July 9; Manitoulin Dist., Aug. 4-5; Nipissing Dist., April 19-Oct. 9; Ren- frew Co., May 5-8; Muskoka Dist., May 4-Oct. 9; Bruce Co., July 18-Aug. 22; Grey Co., July 28; Dufferin Co., July 28; Simcoe Co., Aug. 21-Oct. 9; Ontario Co., Aug. 18; Victoria Co., April 27; Peterborough Co., June 20; Hasting Co., April 26-Aug. 7; Frontenac Co., May 22: Lanark Co., June 7- Aug. 28; Carleton Co., April 24-Nov. 26; Leeds Co., Oct. 20-25; Huron Co., Aug. 3-10; Perth Co., Aug. 8-17; Waterloo Co., May 4; Wellington Co., April 8-Dec. 19; Halton Co., July 29-Aug. 15; Peel Co., March 28-June 17; York Co., May 5-Aug. 16; Northumberland Co., Aug. 22; Middlesex Co., June 11-Nov. 15; Oxford Co., March 28-April 14; Brant Co., July 27- Aug. 5; Wentworth Co., April 13-Oct. 27; Norfolk Co., April 1-Dec. 3; Haldimand Co., May 31; Lincoln Co., Aug. 11. Biological notes Simulium vittatum is multivoltine, and is one of the most abundant and widely distributed species in the province. It may possibly be a com- plex of two species in Ontario. The eggs of the last generation hatch in late autumn and the larvae develop slowly until late winter or early spring. 125 Larvae are found on a wide range of submerged objects in streams of — widely varying widths and the summer generation of larvae can withstand water temperatures in excess of 80°F. Adults begin to emerge from over- wintering larvae in mid-April in extreme southern Ontario, and in early May in Algonquin Park (Davies, 1950). The early emerging females are autogenous and have eggs almost mature (Wu, 1931; Davies and Peterson, 1956). In one stream in Algonquin Park it appeared that a separate popu- lation of adults, from overwintering eggs, emerged in late June and early July (Davies, 1950, p. 189), and thereafter it was difficult to distinguish between populations from overwintering larvae or eggs, or from new eggs introduced by immigrant females. In extreme southern Ontario, females that emerged in the summer were only about one percent autogenous. This species forms mating swarms (Peterson, 1962b). Oviposition may occur on trailing vegetation, water-lapped rocks and other cbjects, cement walls of sluiceways, and on logs. They have been observed ovipositing while set- tled and by tapping their abdomens to the water while in flight (Davies and Peterson, 1956). Near Hamilton, oviposition continues until early September. Only twice have the authors observed females of S. vittatuwm feeding on humans, although flies have been collected crawling on humans many times. This species, at times, may be a pest of cattle (authors’ data; Teskey, 1960), and especially of horses in the southwest portion of the Province. Acknowledgments The authors appreciate the ready help of Mr. G. E. Shewell, Ento- mology Research Institute, Ottawa, and Dr. Alan Stone, Insect Identifica- tion and Parasite Introduction Research Branch, U.S. Department of Agriculture, Washington, D.C., for information and advice, and for per- mitting us to examine specimens under their direction. We are grateful also for specimens sent to us by Mr. R. W. Dunbar, Department of Botany, University of Toronto; Dr. J. R. Anderson, Department of Parasitology, University of California, Berkeley, and Dr. K. M. Sommerman, Arctic Health Research Centre, Anchorage, Alaska. The technical assistance of Mrs. H. Gyorkos, Mrs. T. Goodman and Miss G. C. Taylor, McMaster University, and of Messrs E. F. Bond, J. W. McWade, and R. D. 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V. and Daviks, D. M. (1960). Observations on some insect predators of black flies (Diptera: Simuliidae) of Algonquin Park, Ontario. Canad. J. Zool. 38: 9-18. Puri, I. M. (1925a). On the life-history and structure of the early stages of Simuliidae (Diptera, Nematocera). Part I. Parasitology 17: 295-3384. Puri, I. M. (1925b). On the life history and structure of the early stages of Simuliidae (Diptera, Nematocera). Part II. Parasitology 17: 335-369. REMPEL, J. G. and ARNASON, A. P. (1947). An account of three successive outbreaks of the black fly, Simulium arcticum, a serious livestock pest in Saskatchewan. Sci. Agric. 27: 428-445. RILEY, C. V. (1887). Simuliidae. In Report of the entomologist. Rep. Comm. Agric. for 1886: 492-517. ROTHFELS, K. H. (1956). Black flies: siblings, sex and species grouping. J. Hered. ee AAS 1 2oe Rustzov, I. A. (1936). A new species of black fly.(Simulium oligocenicum, sp.n.) from amber [in Russian]. Rep. Acad. Sci. U.S.S.R. 2, 8(94) : 347-349. Rustzov, I. 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(1905). Simuliidae. In The Diptera of Minnesota. Tenth Ann. Rep. State Ent. Minn., agric. Exp. Sta., St. Anthony Park: 70-76. WILLISTON, S. W. (1908). Manual of the families and genera of North American Dip- tera. 3rd ed. James T. Hathaway, New Haven, Conn. WOLFE, L. S. and PETERSON, D. G. (1959). Black flies (Diptera: Simuliidae) of the forests of Quebec. Canad. J. Zool. 37: 137-159. Wo re, L. S. and PeTerson, D. G. (1960). Diurnal behaviour and biting habits of black flies (Diptera: Simuliidae) in the forests of Quebec. Canad. J. Zool. 38: 489-497. Wu, Y. F. (1931). A contribution to the biology of Simulium (Diptera). Mich. Acad. Sci., Arts and Letters (1930) 13: 543-599. (Accepted for publication: April 19, 1962) 130 flagellum. clypeus eye sensory vesicle labrum galea of maxilla ~ mandible maxillary palpus hypopharynx ~ labellum sensory vesicle opening. SG Sib Fig. 2. Anterior view of head of Simuliuwm venustum female. Fic. 3. Third segment of maxillary palp of female, showing sensory vesicle. FIG. 3a, Simulium aestivum. FG. 3b, Simulium excisum. 131 pleural membrane pleural tuft scutellum scutum postscutellum pronotum ee proepisternum basal fringe katepisternum A Fic. 4. Side view of thorax of Simuliwm euryadminimulum female. Fic. 5. Right wing of Prosimulium fuscum male. 132 ; ee nt Sey 4 lateral cervicale proepisternum basisternum calcipala Fic. 6. Anteroventral view of the basisternum and precoxal bridge of the female. FiG. 6a-b, Simulium emarginatum. FIG. 6c, Simulium quebecense. Fic. 7. Right metathoracic leg of the female. Fig. Ta, Simulium excisum. Fic. Tb. Simuliwm latipes. Fic. 8. Furcasternum of female metasternum showing internal dorsal arms. FIG. 8a, Simulium quebecense. Fic. 8b, Simuliwm pugetense. Fic. 8c, Simuliwm latipes. 133 0.1 mm. | T. tibblesi (in iu stem oS enital fork og | -arm terminal plate ovipositor lobe =anal lobe cercus P magnum : B multidentatum Fig. 9. Female genitalia of Twinnia tibblesi. Fics. 10-11. Female genitalia of Prosimulium spp. 134 P. fontanum P fuscum Di etin P vernale Fics. 12-15. Female genitalia of Prosimulium spp. 135 P. decemarticulatum —————} Fics. 16-17. Female genitalia of Prosimulium spp. Fics. 18-19. Female genitalia of Cnephia spp. 136 at -C.emergens : C. mutata Ry NH WV tse ht NS AS Mitt Mos Al al ————} C. ornithophilia ————____——_ C. invenusta ae Fics. 20-23. Female genitalia of Cnephia spp. 137 Sl S. qureum C.dacotensis ©0002 cecc00er}2 S yok nense : S. furculatum ZS Fic. 24. Female genitalia of Cnephia dacotensis Fics. 25-27. Female genitalia of Simulium spp. 138 ene | S. congareenarum 2! 90000 0c00f008 ° 2609600 980000000 28 S. innocens 310 Fics. 28-31. Female genitalia of Simulium spp. 139 S. excisum 2g S, rivuli S| S. emarginatum Pt hes YS. euryadminiculum —— — : q on) i : 2 =: Ly Gf jj: Pj Yt fe! Dos / AAS 53 : 3 : | °2Se eroxtonl S. gouldingi Fics. 32-35. Female genitalia of Simuliwm spp. 140 S. latipes S. aestivum Sif S. pugetense S. quebecense Figs. 36-39. Female genitalia of Simulium spp. 141 3 S. impar nnn 00000 — S.vittatum - S. pictipes 43 142 S. parnassum S. tuberosum Fics. 44-47. Female genitalia of Simuliwm spp. 143 oo SHCORDIS S. venustum ——) S. decorum S. verecundum Fics. 48-51. Female genitalia of Simulium spp. 144 Sl T. tibblesi basistyle dististyle -yentral plate P. multidentatum “Ny vi = WM) NI, Wi vy! | i re WAN: ed = truicyl XG) ( So WS OS Fic. 52. Male genitalia of Twinnia tibblesi. Fics. 53-54, Male genitalia of Prosimulium spp. 145 P. gibsoni P. decemarticulatum I ee CLG) Ay) 4 SSSS QQ ny SVS qy~w wo: te C. invenusta DD oY, 146 P. vernale Fic. 58. Male genitalia of Cnephia invenusta. Fics. 55-57. Male genitalia of Prosimuliwm spp 7 C.abdita C.denaria SS ——! S77 SS S SWS —~~ << ~~ Se C. emergens a C.mutata Fics. 59-62. Male genitalia of Cnephia spp. 147 C.dacotensis S. euryadminiculum —_——— S. baffinense VIE oe ss d,/, jill Lh TE CA yd Wy) We 65 66 Fic. 63. Male genitalia of Cnephia dacotensis. Fics. 64-66. Male genitalia of Simuliwm spp. 148 S. congareenarum S. excisum % Y/, parameral teeth ies 68 a eae SS. innocens S. rivuli ¥ Figs. 67-70. Male genitalia of Simulium spp. 4 149 S. aestivum eae Joe S. latipes paramere dorsal sclerite a it ———— S. croxtoni ae are S. gouldingi Figs. 71-74. Male genitalia of Simuliwm spp. 150 5. impar S. furculatum Soon S. pugetense S. quebecense E pea ee Fics. 75-78. Male genitalia of Simuliwm spp. a ee, : 151 San Tee seCe S. aureum | . S. jenningsi form A ijn VRE Lyd}, Ue / i) } Wh Wai [= ( Pas 80 S. longistylatum S. pictipes tess) : ees : tees ic t Brest Soka | teat 7 ‘o zA-_y \ oY — van ' nee t : ‘vs Df, ip H we yin N YEN lv rey 82 Fics. 79-82. Male genitalia of Simuliuwm spp. 152 ee. S. parnassum Oi care cea S. rugglesi S. tuberosum ee Gees S. vittatum Figs. 83-86. Male genitalia of Simauliwm spp. 153 Rass s Sas S. corbis - §. decorum S. venustum S. verecundum 89 3 90 Fics. 87-90. Male genitalia of Simulium spp. 154 PREY-CAPTURING METHODS OF SPIDER FAMILIES AS A POSSIBLE EXPLANATION FOR THEIR DISTRIBUTION IN ONTARIO ROGER I. C. HANSELL Research Laboratory, Research Branch, Canada Department of Agriculture, Vineland Station, Ontario At present there is no general work on the distribution of spiders in Ontario. Emerton (1917, 1920) discussed the distribution of some common species in Ontario and later (1928) published a list of spider species of the Lake Abitibi region. Kurata published lists of spiders of the Sault Ste. Marie district (1942), Prince Edward County (1941), York County (1939), and the Lake Nipissing and Temagami regions (1943). However, these papers were lists of species in localized areas and seldom included any further biological data. The ecological studies of the Mumas (1949) and of Lowrie (1942) indicated that different plant communities support pop- ulations of spiders of different familial composition. Moreover, Lowrie (1948) found “an ecological succession of spiders corresponding to plant succession’. This evidence suggested that the distribution of spiders is affected by the flora of an area and accordingly it might be expected that differences in the distribution of families in different forest zones would be noted. An examination of the distribution of the more than 25,000 spiders in the collection of the Royal Ontario Museum gave an opportunity to test this hypothesis. Spiders capture their prey in various ways and a consideration of their preying habits indicates that certain physical char- acteristics of the environment are required by each preying method. In the following pages it is shown that each of the different forest zones in Ontario provides physical characters more suitable for one than for others of these preying methods. The distribution of the families of spiders in Ontario is at least partly explained herein by the correlation between method of obtaining prey and the type of vegetation in the environment. Materials and Methods The spiders examined in this study were part of the collection of the Royal Ontario Museum, Toronto, Ontario. This collection contains over 25,000 specimens, of which over 85 per cent were collected by the Mu- seum staff. Material from northern Ontario was collected on special Museum trips. The specimens were identified by T. B. Kurata, Weed. Gertsch, and others. However, owing to recent changes in generic and Specific nomenclature, identifications at the species level are questionable in many cases. Identifications at the family level were found to be reliable. As there was no uniformity in methods and intensity of collection, absolute numbers of specimens in the various families could not be used to indicate distribution. Relative abundance was determined as the number of specimens of a given family divided by the total number of specimens of all families collected in a given vegetational zone, expressed as a percentage. It is assumed that ‘the locations at which spiders were col- lected are randomly distributed in each zone. To eliminate as many of the non-quantitative collections as possible, the file card records of the col- lection were analysed. The records for locations with fewer than five species collected, regardless of number of specimens, were discarded arbitrarily. The records of the Clubionidae were absent from the file cards of the collection. It is estimated, on the basis of Kurata’s papers (1939, 1941, 1942, 1943), that this family represents about 5 per cent of the total spiders in the collection. Proc. Entomol. Soc. Ont. 92 (1961) 1962. 155 The zones of vegetation used are the forest regions of Rowe (1959). Rowe considered a forest region to be ‘“‘a major geographic belt or zone, characterized vegetationally by a broad uniformity both in physiognomy and the composition of the dominant tree species”. MANITOBA QUEBEC ONTARIO Fic. 1. Rowe’s forest regions in Ontario: Area 1—Southern Deciduous; Area 2— Great Lakes-St. Lawrence; Area 3—Boreal Forest; Area 4—Boreal Forest and Barrens. Results For the purposes of this paper spiders are considered to have four primary ways of capturing their prey :— 1. Hunting on the ground: Lycosidae, Gnaphosidae, and Pisauridae. These spiders pursue and seize their prey, and would be expected to be found most commonly in open areas with little ground cover. 156 2. Hunting on foliage: Salticidae, Thomisidae, and Mimetidae. The jumping spiders (Salticidae) attach themselves to vegetation by a dragline of silk before leaping on the.r prey. The crab spiders tend to ambush their victims in flower heads and leaves. The mimetids prey ex- clusively on other spiders on foliage. Obviously these spiders require abundant foliage. 3. Trapping with orb webs: Argiopidae, Tetragnathidae, and Ulo- boridae. The argiopids are the common orb weavers. The tetragnathids build orb webs in vegetation in damp area. The Uloboridae are common spiders which build webs shaped like a sector of a circle. Orb webs need an aerial support such as tall grass, bushes, or trees. _ 4, Trapping with irregular webs in various sites: Linyphiidae, Theridiidae and Agelenidae. These spiders build irregular, dome-shaped, or sheet webs supported by a variety of subtrates, from dead leaves and grass to trees. Rowe’s forest regions of Ontario are (Fig. 1): Area 1. Southern Deciduous Region, characterized by a _ broad-leaved flora having a close relationship with the forests of the east-central United States. Most of the land is setled, and the natural vegetation reduced to wocdlots. Area 2. Great Lakes-St. Lawrence Forest Region, characterized by a mixed flora of coniferous and deciduous types: pine, hemlock, birch, maple, and oak predominate. The land is widely settled in the southern part of this region. Area 3. Boreal Forest Region, characterized by a coniferous flora dom- inated by sprucs. Area 4. Boreal Forest and Barrens Region, characterized by a flat topo- graphy, poor drainage, and a subarctic ‘muskeg’ flora with coniferous forests growing on drained alluvial river banks. White spruce pre- dominates on the maritime tree line that extends along the line of Hudson’s Bay. Black spruce and tamarack are found in the muskeg. Figure 2 compares the families as percentages of total numbers of specimens collected in each area. The total number of specimens and the number of collection points in each area are:— Area 1, 4,930 at 24 points; Area 2, 12,815 at 121 points; Area 3, 1,296 at 14 points; Area 4, 596 at 4 points. The small sample from Area 4 makes the percentages in that area less reliable. In the Southern Deciduous Region (Area 1, Fig. 2) the lycosids were only 6 per cent. The argiopids were 20 per cent and the most numerous family. The salticids comprised 16 per cent of the total, making them the third most numerous family. In the Great Lakes-St. Lawrence Region (Area 2, Fig. 2), the lycosids increased to 9 per cent, the argiopids dropped to 12 per cent, and the theridiids were 19 per cent. In the Boreal Forest Region (Area 3, Fig. 2), the lycosids further increased to 25 per cent, the tetragnathids were 6 per cent, and the agriopids rose to 20 per cent. The linyphids were 17 per cent and the thomicids 12 per cent. In the Forest and Barrens Region (Aten 4, Fig. 2), the lycosids made up 87 per cent of the total, the tetragnathids 22 per cent, and the argiopids 17 per cent. The linyphiids made up 12 per cent, the salticids 5 per cent and the dictynids 4 per cent. The tetragnathids and agriopids 157 are sometimes grouped in the family Araneidae, which would then contain 89 per cent of the spiders collected. The large number of tetragnathids makes this percentage surprisingly high. The two most intensively col- lected locations in the Forest and Barrens Region were Fort Severn, PERCENTAGE OF TOTAL NUMBERS COLLECTED AREA #1 Tod Sd 6. Feo. TOTS AREA #2 LEGEND 1 LYCOSIDAE 2 TETRAGNATHIDAE : 3 ARGIOPIDAE See Sn a9 0 1112 13 | OCRY Cee 40 ee + (NESTICIDAE) 5 SALTICIDAE 30 6 DICTYNIDAE AREA #3 +(AMAUROBIIDAE) 20 7 THOMISIDAE 8 GNAPHOSIDAE 9 THERIDIIDAE Posh os o | 10 PISAURIDAE 123045 6 27 89. 10 112 13 | PAGEL ENE + (HAHNIIDAE) 12 MIMETIDAE 13 ULOBORIDAE AREA #4 We 2 Sian Bi Oe eer a ON delle ate FAMILIES OF SPIDERS Fic. 2. The relative percentage abundance of major families of spiders in the four forest zones of Ontario. 158 which is on the marine tree limit of Hudson’s Bay, and Fort Albany, which is further south on James Bay. At Fort Severn, 189 lycosids, 48 argiopids and 13 tetragnathids were collected in a total of 305 specimens. At Fort Albany, there were only 13 lycosids, with 51 argiopids and 120 teragna- thids in 265 specimens. This wide variation was to be expected in the region of the tree line. In the province as a whole, ground hunters comprised 21 per cent of the 19,637 specimens collected (Table 1), foliage hunters 19 per cent, orb web builders 28 per cent, and other web builders 32 per cent. As expected, ground hunters were numerous in the Forest and Bar- rens Region, they continued numerous in the Boreal Forest Region, and then dropped sharply in the Great Lakes-St. Lawrence Region. This may be explained by the increased ground cover in deciduous forests compared to spruce-dominated coniferous forests. Foliage hunters were scarce in the Forest and Barrens Region, increased greatly in the Boreal Forest Region, and were most numerous in the Southern Deciduous Region. The orb web builders were surprisingly high in the Forest and Barrens Region and low in the Great Lakes-St. Lawrence Region. The great number in the Forest and Barrens Region seems largely to have been due to the predominance of tetragnathids at one collecting point that was be- low the marine tree limit, i.e., where there was more tall vegetation than farther north. The low relative numbers of orb weavers in the Great Lakes-St. Lawrence Region may have been due to the great increase in other web-spinning spiders, which were scarce in the Forest and Barrens Region, increased in the Boreal Forest Region, and formed 51 per cent of the spiders collected in the Great Lakes-St. Lawrence Region. The in- creased amount of ground cover and the broad-leaved character of the litter in the region may explain this as many of these spiders build small webs needing very little substrate. In conclusion, this analysis suggests that the amount and type of vegetation in the various forest zones affects the distribution of spider families in Ontario. Web-spinning and foliage- hunting spiders tended to have greatest relative abundance in forested regions whereas ground- hunting spiders tended to have greatest relative abundance in the mixed barren and forest region. a 1. Relative percentage abundance of four types of spiders in the four forest zones of Ontario. pan Ground Foliage Orb web Other web hunter hunter weaver weaver 1 8 26 28 38 2 12 17 20 51 3 of 17 26 16 4 aire 7 40 16 Totals a 19 28 Se Acknowledgments I would like to thank Dr. G. Wiggins of the Royal Ontario Museum for his assistance and advice in using the museum collection, and Dr. D. A. Chant, Research Laboratory, Vineland Station, Ontario, and Dr. A. L. Turnbull, Entomology Research Institute for Biological Control, Belleville, Ontario, for their helpful criticisms and suggestions. 159 Literature Cited EMERTON, J. H. (1917). Recent studies of Canadian spiders. Canad. Ent. 49: 13-16. EMERTON, J. H. (1920). Catalogue of the spiders of Canada known to the year 1919. Trans. Roy. Canad. Inst. 12: 309-338. EMERTON, J. H. (1928). A faunal investigation of the Lake Abitibi region, Ontario: Spiders from the Lake Abitibi region. Univ. Toronto Studies: Biol. Ser. 32. Kurata, T. B. (1939). A list of the spiders of York County, Ontario, Canad. Canad. Fld. Nat. 53: 80-83. Kurata, T. B. (1941). A list of the spiders of Prince Edward County, Ontario. Univ. Toronto Studies: Biol. Ser. 48: 107-115. KuraTA, T. B. (1942). A list of spiders collected in the Sault Ste. Marie region, On- tario. Contrib. Roy. Ont. Mus. 21: 164-165. KouraTA, T. B. (1948). The spiders of the Lake Nipissing and Lake Temagami regions, Ontario. Canad. Fld. Nat. 57: 9-13. Lowrig, D. C. (1942). The ecology of the spiders of the xeric dunelands in the Chicago area. Bull. Chicago Acad. Sci. 6: 161-189. Lowrig, D. C. (1948). The ecological succession of spiders of the Chicago area dunes. Ecology 29: 334-351. Muma, M. H. and K. E. Muma. (1949). Studies on a population of prairie spiders. Ecology 80: 485-508. Rowe, J. S. (1959). Forest regions of Canada. Canad. Dept. Northern Affairs Nat. Res., Forestry Branch. Bull. 122. Accepted for publication February 1, 1962 AN ANNOTATED CHECK LIST OF THE NON-PARASITIC HALICTIDAE (HYMENOPTERA) OF ONTARIO GERHARD KNERER and C. E. ATWOOD Department of Zoology, University of Toronto, Toronto, Canada The family Halictidae is a very large one which has iong been of in- terest to entomologists because it contains some species which show a primitive grade of social organization. It is also a family in which separa- tion and identification of species is very difficult. Since studies of distri- bution, behaviour, social habits etc. are impossible until the species can be identified, we have become involved in an effort to clarify the taxonomic position of the Ontario species as a prelude to other studies. This led to the compilation of this check list which we have found so useful that we feel it may be of interest to other hymenopterists. Dr. T. B. Mitchell’s recent book (Mitchell, 1960) has done a great deal to bring order in the halictid chaos of eastern North America. However, collecting of bees in Ontario has been in general very haphazard and no hymenopterist has really worked on the Halictidae of Ontario in recent times. Therefore the Ontario fauna is not well represented in collections and indeed Dr. Mit- chell’s book really deals with the bees of the ‘eastern United States’ so that an adequate treatment of Ontario bees is not to be expected from it. We hope that this paper, together with several others now in prepar- ation, will do something to bring more order to this present confused situation. At the same time we realize that it cannot be considered as in any way final but that it is a working tool which will in time ce re- designed. Proc. Entomol. Soc. Ont. 92 (1961) 1962. 160 Genus HALICTUS Latreille Black or dull greenish bees from 7-14 mm. long. with well defined apical abdominal fasciae. Wing venation is strongly developed including the outermost veins. Four species are commonly found in Ontario, Halictus ligatus Say being probably the most common halictine bee in eastern North America. : Halictus confusus Smith 9J Distribution by counties: Carleton, Cochrane, Dufferin, Durham, Elgin, Essex, Frontenac, Glengarry, Grenville, Haliburton, Halton, Hastings, Kent, Lanark, Leeds, Muskoka, Nipissing, Ontario, Peel, Simcoe, Stormont, Sudbury, Timiska- ming, Victoria, Wellington, York. Flower records: Amelanchier, Anaphalis, Antennaria, Apocynum, Barbarea, Brassica, Chrysanthemum, Crataegus, Epilobium, Huphorbia, Fragaria, Hieracium, Lepidium, Malva, Melilotus, Prunus, Ranunculus, Rhus, Rubus, Salix, Solidago, Taraxacum, Trifolium. Flight period based on our collections: April to September. Smallest (7 mm.) bee in this genus, dull metallic with conspicuous apical abdominal fasciae. Apparently very adaptable, occurs in numbers from the Lake Erie region to the Cochrane district. Utilizes almost any type of soil for nesting sites. Semi-social tendencies apparent where two or more females share common burrows. Cells horizontal, almost sessile on vertical main shafts. Atwood (1933) observed nesting sites in light, dry soil in Nova Scotia. The burrows were concealed by debris or opened into dense tufts of grass. Cells were few and heavily parasitized. Halictus ligatus Say °° Distribution by counties: Bruce, Carleton, Dufferin, Durham, Dundas, Elgin. Essex, Gray, Haldimand, Haliburton, Halton, Hastings, Kent, Lambton, Lanark, Leeds, Middlesex, Muskoka, Nipissing, Ontario, Oxford, Peel, Perth, Simcoe, Stormont, Victoria, Wellington, York. Flower records: Antennaria, Barbarea, Bre assicd, Corde Chrysanthemum, Cichori- um, Cirsium, Cornus, Crataegus, Epilobium, Eriger on, Huphorbia, Frag- aria, A elianthus, Hieracium, Inula, Lepidium, Malus, Medicago, Melilotus, Onopordum, Potentilla, Prunus, Ranunculus, Raphanus, Rhus, Rosa, Ru- bus,Rudbeckia, Salix, Sisyrinchium, Solidago, Sonchus, Taraxacum, Trag- opogon, Trifolium. Flight period based on our collections: April to aber: This abundant black bee shows great variation in size and color of pubescence. It becomes uncommon toward the 49th parallel. Nests occur in a variety of habitats but dry and firm so:l often supports a numerous population. Marking experiments of nesting populations in spring and summer showed. that several females will share a common burrow and give rise to more than two dozen females in the summer brood. Smaller size and short life indicate that the latter belong to an incipient worker caste. During the hours of foraging activities, nest openings are manned by “guards” which allow passage to inmates of the burrow but block the shaft with their abdomen if threatened by intruders. This duty is shared by males during fall. 161 Halictus parallelus Say 9% Distribution by counties: Dufferin, Durham, Muskoka. Flower records. Melilotus, Potentilla, Rhus, Rubus, Solidago. Flight period based on our collections: June to September. The largest of Canadian halictine bees. Black with infumate wings. Exhibits almost no variation in our area. A powerful flier and very alert. This is probably the reason for its scant representation in collections. It seems to be the counterpart of Halictus farinosus Smith which is common on the Pacific coast. Packard (1868) ocbserved a small colony in a footpath and a gravel road in Massachusetts. Halictus rubicundus (Christ) 2° Distribution by counties: Algoma, Brant, Bruce, Carleton, Cochrane, Dufferin, Durham, Essex, Frontenac, Haliburton, Hastings, Kenora, Kent, Lanark, Leeds, Lincoln, Muskoka, Nipissing, Ontario, Peel, Perth, Simcoe, Sudbury, Timiskaming, Victoria, Wellington, York. Flower records: Amelanchier, Anaphalis, Barbarea, Brassica, Chrysanthemum, Cutr- sium, Cornus, Crataegus, E'pilobium, Erigeron, Euphorbia, Fragaria, Malus, Medicago, Melilotus, Nepeta, Potentilla, Prunus, Ranunculus, Rhus, Rubus, Rudbeckia, Salix, Solidago, Sonchus, Taraxacum, Tragopogon, Trifolium. Flight period based on our coilections: April to September. A large black bee of holarctic distribution. It has been described under different specific and subspecific names on account of minor variations. Atwood (1933) suggested their synonymy after comparing them with a European series of H. rubicundus (Christ). Nests occur in a variety of habitats from sand banks to gravelly soil. Large nesting colonies were observed at Dyers Bay, Bruce County (personal communication Profes- sor Pengelly, Guelph, Ontario). Atwood (1933) found colonies nesting in a silt dyke in Nova Scotia. Genus LASIOGLOSSUM Curtis Black bees with the outermost veins of forewings fainter than the basal venation. Their size ranges from 8-10 mm. There are six species known from Ontario, of which the first four below look almost alike and can only be separated by microscopic criteria. The last two species are holarctic and attain a wide range in our province but hardly extend south of its border. Lasioglossum athabascense (Sandhouse) 9¢ Distribution by counties: Algoma, Lincoln, Muskoka, Sudbury, Wellington, York. Flower records: Cornus, Rubus, Ranunculus. Flight period based on our collections: April to July. Large and black, very similar to L. coriacewm, L. forbesu, and L. fuscipenne. Records are very scanty in Ontario with the exception of Sud- bury. According to collections it seems to be one of the predominant halic- tine bees in Nova Scotia. 162 Lasioglossum coriaceum (Smith) °¢ Distribution by counties: Bruce, Carleton, Dufferin, Durham, Essex, Frontenac, Grenville, Halton, Hastings, Kent, Muskoka, Oxford, Peel, Wellington, York. Flower records: Aster, Barbarea, Cornus, Crataegus, Fragaria, Malva, Melilotus, Potentilla, Rhus, Rubus, Salix, Taraxacum. Flight period based on our collections: May to September. Holarctic, more frequent in the southern and central part of the province. No nesting sites were observed. Lasioglossum forbesti. (Robertson) 9 Distribution by counties: Algoma, Carleton, Dufferin, Durham, Frontenac, Grenville, Hastings, Leeds, Muskoka, Nipissing, Oxford, Peel, Peterborough, Simcoe, Sud- bury, Wellington, York. 3 Flower records: Barbarea, Chrysanthemum, Crataegus, EHrigeron, Melilotus, Poten- tilla, Prunus, Rubus, Salix, Solidago, Taraxacum, Tragopogon, Trifolium. Flight period based on our collect:ons: April to September. Common in moraine and sandy country. Nesting colonies were ob- served on sandy slopes in meadows. Construction of burrows began early in June; nests were in close proximity to each other and conspicuous through mounds of loose material around entrance of the burrows. Males were present from August to late September on Solidago. Lasioglossum fuscipenne (Smith) 9° Distribution by counties: Essex, Kent. Flower records: Geranium, Salix, Smilacina, Taraxacum. Flight period based on our collections: June to July. Limited to the southern counties. No details of life history known. Lasioglossum leucozonium (Schrank) °° Distribution by counties: Algoma, Bruce, Dufferin, Dundas, Durham, Elgin, Frontenac, Hali- burton, Hastings, Kent, Lanark, Leeds, Lennox, Muskoka, Ontario, Peel, Simcoe, Victoria, Wellington, York. Flower records: Anaphalis, Apocynum, Barbarea, Cornus, Crataegus, Fragaria, Hier- acum, Ranunculus, Rubus, Salix, Solidago, Taraxacum, Tragopogon. Flight period based on our collections: May to September. Holarctic and very common in Ontario, more so in the northern parts than in the south. Nests occur in great numbers in a variety of habitats and resemble those of Halictus ligatus. Males appear in late July and vanish with the first frosts. Lasioglossum zonulum (Smith) 93 Distribution by counties: Algoma, Bruce, Carleton, Cochrane, Dufferin, Dundas, Essex, Gren- ville, Grey ,Haliburton, Hastings, Huron, Kenora, Lennox, Manitoulin, Muskoka, Nipissing, Peel, Perth, Simcoe, Sudbury, Wellington, York. Flower records: } Asparagus, Barbarea, Carduus, Chrysanthemum, Cichorium, Cornus, 163 Crataegus, Epilobium, Fragaria, Hieracium, Malva, Medicago, Melilotus, Potentilla, Prunus, Ranunculus, Rhus, Rosa, Rubus, Salix, Solidago, Son- chus, Taraxacum, Tragopogon, Trifolium. Flight period based on our collections: May to September. Holarctic; like L. leucozonium, it is more abundant in the northern parts of the province. Nests were found in jack pine stands in the Cochrane area, the burrows consisting of vertical ene with narrower lateral branches leading to horizontal cells. Genus EVYLAEUS Robertson This genus is closely related to Lasioglossum. Main difference: in the females are the smaller size (5-8 mm.) and a reduction of the second inter eubital vein. Both criteria are less pronounced in the males, which may make it advisable to treat both genera in one comprehensive key. Nine recognized species are recorded from Ontaric but further work is needed to clarify the association of sexes in several forms. Evylaeus cinctipes (Provancher) °° (2=arcuatus Robt.) (new synonomy) Distribution by counties: Algoma, Bruce, Dufferin, Durham, Frontenac, Grenville, Haliburton, Hastings, Kent, Lanark, Leeds, Middlesex, Muskoka, Peel, Peterborough, Simcoe, Sudbury, Victoria, York. Flower records: Amelanchier, Barbarea, Crataegus, Malus, Melilotus, Rhus, Rubus, Salix, Solidago, Taraxacum. Flight period based on our collections: April to September. Fairly common throughout southern and central Ontario but becom- ing sparse near the 49th parallel. There is a distinctive smaller summer form which appears in early July and seems to have a food preference for Rhus. Males are present in August and September and definite asso- ciation with females has now been made; the male described in the litera- ture (Mitchell, 1960, p. 349) under this name is actually EF. truncatus (Rob- ertson) q.v. 3 Atwood (1933) gave an account of nesting colonies in Nova Scotia as arcuatus Robt. The spring females did not hibernate in the summer tun- nels and differed in sculpturing and size from the summer brood. Evylaeus divergens (Lovell) 2 Distribution by counties: Carleton, Dufferin, Durham, Essex, Frontenac, Grenville, Halibur- ton, Hastings, Kent, Lanark, Leeds, Muskoka, Peel, Sudbury, Wellington, York. Flower records: Barbarea, Crataegus, Fragaria, Geranium, Malva, Nasturtium, Po- tentilla, Rubus, Salix, Sisyrinchium, Solidago, Taraxacum. Flight periods based on our collections: May to September. Small and black bee, found in southern and central Ontario but never abundantly. The male is not known. Evylaeus fox (Robertson) °J Distribution by counties: Carleton, Dufferin, Frontenac, Grenville, Haliburton, Hastings, Lan- ark, Leeds, Lincoln, Muskoka, Peel, Sudbury, Victoria, Wellington. York. 164 Flower records: Amelanchier, Anaphalis, Apocynum, Barbarea, Brassica, Cornus, Crataegus, Fragaria, Hieracium, Lotus, Melilotus, Raphanus, Rubus, Salix, Solidago, Taraxacum, Vaccinium. Flight period based on our collections: April to September. Black and small, abundant in sandy areas where this species nests gregariously. Males appear rather early in July and August on Melilotus and Solidago. E'vylaeus macoupinensis (Robertson) ~ Distribution by counties: Durham, Muskoka. Flower records: Solidago. Flight period based on our collections: August. There is some doubt as to whether the male and female described under this name (Robertson 1895) really belong to the same species. Only further work can settle this point. Evylaeus nelumbonis (Robertson) 9 Distribution by counties: Muskoka. Flower records: Solidago. Flight period based on our collections: August and September. Medium sized, black. A total of only four bees are in the collection. No details of its life history are known. Evylaeus pectoralis (Smith) 9 Distribution by counties: Carleton, Durham, Essex, Haliburton, Kent, Leeds, Muskoka, Oxford, Sudbury, Victoria, York. Flower records: Chrysanthemum, Crataegus, Erigeron, Fragaria, Geranium, Impati- ens, Potentilla, Ranunculus, Rubus, Salix, Smilacina, Solidago, Taraxacum. Flight period based on our collections: May to September. A holarctic, medium sized black bee. Occurs in considerable numbers sometimes, especially in sandy areas in the Canadian Shield. No informa- tion on its life history. Evylaeus quebecensis (Crawford) 9¢ Distribution by counties: Algoma, Cochrane, Leeds, Peel, Sudbury, Timiskaming, York. Flower records: | Crataegus, Fragaria, Prunus, Rubus, Salix, Solidago, Taraxacum. Flight period based on our collections: May to September. Medium sized black bee, more abundant in northern parts of the pro- vince. Nothing is known of its life history. Evylaeus rufitarsis (Zetterstedt) Distribution by counties: Algoma, Cochrane, Muskoka, Nipissing, Peel, Sudbury, Timiskaming. Flower records: Apocynum, Barbarea, Cornus, Fragaria, Prunus, Rubus, Salix, Soli- —dago, Taraxacum, Trifolium. 165 Flight period based on our collections: May to September. Holarctic, similar in appearance to FE. quebecensis and sharing its range. No work has been done on its life history in North America. Evylaeus truncatus (Robertson) 2 Distribution by counties: Bruce, Carleton, Durham, Frontenac, Grenville, Haliburton, Lanark, Leeds, Muskoka, Nipissing, Simcoe, Sudbury, Thunder Bay, Victoria. Flower records: Amelanchier, Anaphalis, Barbarea, Crataegus, Fragaria, Malus, Medi- cago, Melilotus, Prunus, Salix; Solidago, Taraxacum, Viburnum. Flight period based on our collections: May to September. — Larger than other bees in the genus, most abundant in the sandy areas of the Canadian Shield, but occurs also in moraine country in sou- thern Ontario. The male of this species was formerly associated with the female of FE’. cinctipes Prov. (Knerer and Atwood, unpublished data). No details of its life history. Genus DIALICTUS Robertson This genus includes a great number of species of closely related, small (3.5 to 7 mm.) and abundant bees. They resemble certain species of Hvy- laeus but differ from them by the metallic color of head and thorax which may be greenish, bluish, brassy or golden. The abdomen is rarely con- -colorous but ranges from ferruginous to black. Species in this genus pre- sent great taxonomic difficulties through intraspecific variability and sexual dimorphism. Many described species are only known from one sex or have been matched up incorrectly. Nests are constructed in a variety of soils and some in wood. Records of thirty-four species exist from Ontario, but intensive collecting in the north western part of the province may. in- crease this figure. Dialictus abanci (Crawford) o Distribution by counties: Algoma, Sudbury, Timiskaming. Flower records: Fragaria, Rubus. Flight period based on our collections: June. Small, clive green in color. Fairly common in northern and western counties. The life history and the male of this species is not known at the present. Dialictus admirandus (Sandhouse) 92 Distribution by counties: Dufferin, Durham, Elgin, Essex, Haldimand, Kent, Middlesex, On- tario, Peel, Wellington, York. Flower records: Barbarea, Cirsium, Fragaria, Lepidium, Medicago, Melilotus, Rhus, Salix, Solidago, Taraxacum, Trifolium, Viburnum. Flight period based on our collections: May to September. Small, greenish in color, abundant in southern counties but com- pletely absent from the northern part of the province. Males were not known previously (Knerer and Atwood, unpublished data). 166 Dialictus alternatus Mitchell Distribution by counties: Timiskaming. Flower records: Solidago. Flight period based on our calectiane: August. Only the male is known so far. Further collecting in the northern districts should yield both sexes and allow correct association. Dialictus anomalus (Robertson) °¢ Distribution by counties: Elgin, Essex, Kent. Flower records: Barbarea, Salix, Solidago. Flight period based on our collections: June to September. Small, greenish, differs from other bees in this genus by having two instead of three submarginal cells in its front wing. Confined to the southernmost counties, never abundant. No knowledge of its life history. -Dialictus brunerit (Crawford) 2 Distribution by counties: Essex. Flower records: Taraxacum. Flight period based on our collections. May. Relatively large for the genus, greenish; one record only from Point Pelee. Nothing is known of its life history. Dialictus coeruleus (Robertson) ?7 Distribution by counties: Essex, Kent, Lanark, Leeds. Flower records: ene, Crataegus, Hydrophyllum, Malus, Solidago, Taraxacum, iola. Flight period based on our collections: May to August. Deep blue, abdomen concolorous, medium size. Colonies were observed in deciduous forest on Point Pelee. Tunnels of woodboring beetles were utilized as burrows in fallen logs of maple. Early foraging was done on the spring flowers of the forest floor. Dialictus cressonii (Robertson) °~ Distribution by counties: Algoma, Bruce, Cochrane, Dufferin, Essex, Frontenac, Grenville, Haliburton, Kenora, Kent, Lanark, Leeds, Lennox, Manitoulin, Muskoka, Parry Sound, Sudbury, Timiskaming, Victoria, Wellington. Flower records: Amelanchier, Anaphalis, Barbarea, Cornus, Crataegus, Epilobium, Fragaria, Geranium, Hieractum, Hydrophyllum, Melilotus, Prunus, Ranun- culus, Rosa, Rubus, Salix, Smilacina, Solidago, Taraxacum, Trifolium, Viburnum. Flight period based on our collections: May to September. Fairly large, greenish bee well represented in the collection from nearly all parts of the province. One record of a nest in wood is reported by Mitchell (1960). 167 Dialictus delectatus Mitchell ¢ Only the male of this species is known at the present. No specimen was taken by the authors. One record exists from the Kenora district of Ontario. (Mitchell, 1960). Dialictus genuinus (Sandhouse) ¢ Nothing is known of this species, including the female. One record | exists for “Ontario’”’ (Mitchell, 1960). No specimens are in the authors’ collection. Dialictus heterognathus Mitchell ° Distribution by counties: Hastings. Flower records: Taraxacum. One record only from southeastern Ontario. The male and life history is so far unknown. Dialictus highlandicus Mitchell ° The male is unknown in this species. The paratype bears the label “Ottawa, Canada’ (Mitchell, 1960). No specimens were taken by the authors. Dialictus imitatus (Smith) ¢ Dialictus tmitatus (Smith) 9= D. inconspicuus (Smith) (new synonymy) The female of this species has also been referred to under the specific names stultus Cresson, sparsus Robt.; hortensis Tovell. (Mitchell 1960, p. 400). Distribution by counties: é : Dufferin, Durham, Elgin, Essex, Frontenac, Glengarry, Grenville, Haliburton, Kent, Lanark, Leeds, Muskoka, Peel, Simcoe, Stormont, Vic- toria, Wellington, York. Flower records: Amelanchier, Barbarea, Chrysanthemum, Cornus, Crataegus, Evri- geron, Euphorbia, Fragaria, Impatiens, Malus, Melilotus, Rhus, Rubus, Salix, Solidago, Taraxacum, Vaccinium. Flight period based on our collections: April to September. Small, green. One of the most abundant bees in southern and central Ontario. Nests were observed in clay, sand and the rich loam of city flower boxes. As a typical “sweat bee’’, it will congregate in numbers on perspir- ing human skin in hot weather. Michener and Wille (1961) investigated its biology and found a caste system with fertilized queens overwintering and giving rise to a semi-sterile summer brood of workers which lay occasional eggs. This species has been described under several names of which only two were retained by Mitchell for the two sexes. Observations on nesting sites established the correct associations of the sexes (Knerer and At- wood, unpublished data). Dialictus laevissimus (Smith) 92° Distribution by counties: Bruce, Cochrane, Dufferin, Durham, Haliburton, Kenora, Muskoka, Nipissing, Simcoe, Sudbury, Timiskaming, York. Flower records: Amelanchier, Anaphalis, Apocynum, Barbarea, Cornus, Epilobium, Fragaria, Hieracium, Prunus, Rhus, Rosa, Rubus, Salix, Solidago, Taraxa- cum, Trifolium. 168 Flight period based on our collections: April to September. A medium sized, greenish bee which occurs in great. numbers in the northern districts of Ontario, where it is the predominant halictine bee. Sandy soil seems to be preferred for nesting sites. Nests were observed in a vertical sand bank along the Credit River. Males of this species have been correctly associated only recently (Knerer and Atwood, 1962). Dialictus lineatulus (Crawford) 9°¢ Distribution by counties: Bruce, Carleton, Dufferin, Durham, Elgin, Essex, Frontenac, Gren- ville, Haliburton, Hastings, Kent, Lanark, Leeds, Middlesex, Muskoka, Northumberland, Peel, Simcoe, Timiskaming, Victoria, Wellington, York. Flower records: Amelanchier, Barbarea, Crataegus, Erigeron, Fragaria, Malus, Meltlo- tus, Potentilla, Prunus, Rhus, Salix, Scilla, Smilacinu, Solidago, Taraxa- cum. , Flight period based on our collections: April to September. Medium, dark green. Well represented in Ontario with the exception of the northern districts. Gregarious nesting sites were found in sandy, southern exposed slopes. The shafts often reach a length of ten inches, leading to a series of lined cells. Dialictus nigroviridis (Graenicher) 9° Distribution by counties: Algoma, Durham, Kenora, Lanark, Manitoulin, Muskoka, Peel, Sud- bury, Timiskaming. Flower records: Amelanchier, Cornus, Fragaria, Prunus, Rosa, Rubus, Salix, Solidago, Trifolium. Large dark green bee. More abundant in northern parts of the pro- vince, especially in the Sudbury and Algoma districts where it is the pre- dominant halictine bee. No data on life history. Dialictus novascotiae Mitchell 9 Distribution by counties: Cochrane, Timiskaming. Flower records: Fragaria, Salix. Flight period based on our collections: June. Large, greenish bee. It appears that the distribution of the species is confined to the northern part of the province. Nothing is known of its biology or male. Dialictus nymphaearum (Robertson) 2 Distribution by counties: Dufferin, Durham, Elgin, Essex, Frontenac, Grenville, Haliburton, Hastings, Kent, Lambton, Lanark, Leeds, Lennox, Muskoka, Oxford, Peel, Victoria, Wellington, York. Flower records: Anaphalis, Antennaria, Barbarea, Cornus, Crataegus, Euphorbia, Fragaria, Hieracium, Malus, Melilotus, Potentilla, Prunus, Ranunculus, Rhus, Rubus, Salix, Sisyrinchium, Solidago, Taraxacum. Flight period based on our collections: May to September. Large (8mm.), greenish with white pubescence. Common in southern and central regions. Not collected from northern parts of the province. No work on its biology has been done. 169 Dialictus oblongus (Lovell) 9 Distribution by counties: Essex, Kent. Flower records: Hydrophyllum, Smilacina, Taraxacum. Flight period based on our collections: May. Dark blue, medium sized bee. Apparently confined to the southern counties. Details on its life history are not available. Dialictus obscurus (Robertson) ? Distribution by counties: Essex. Flower records: Hydrophyllum, Melilotus. Flight period based on our collections: May to August. Medium sized, greenish. Confined to the southern tip of Ontario, where it occurs frequently in deciduous forests. Life history and males are not known. Dialictus orbitatus Mitchell J The female of this species has not been described as yet. One record from Kenora exists (Mitchell, 1960). No specimens were taken by the authors. Dialictus perpunctatus (Ellis) °¢ Distribution by counties: Bruce, Dufferin, Durham, Frontenac, Glengarry, Grenville, Hastings, Lanark, Leeds, Manitoulin, Victoria, Wellington, York. Flower records: Barbarea, Cirsium, Crataegus, Erigeron, Euphorbia, Malus, Ra- phanus, Rhus, Rubus, Rudbeckia, Salix, Solidago, Taraxacum, Trifolium. Flight period based on our collections: May to September. Medium sized, brassy green. Abundant in southeastern Ontario, but scarce in the central and northern districts. No knowledge of life history. Dialictus philanthanus Mitchell Distribution by counties: Sudbury. Flower records: Solidago. Flight period based on our collections: August. Large, dark blue or olive. The biology and the females are unknown. Dialictus pictus (Crawford) °¢ Distribution by counties: Essex, Kent. Flower records: Lepidium, Melilotus, Salix, Solidago. Flight period based on our collections: June to September. Small, brassy with conspicuous orange abdomen. Confined to sou- thern counties where colonies nest in sandy open places along the shores of Lake Erie. The males were not previously known (Knerer and Atwood, unpublished data). Dialictus pilosus pilosus (Smith) 22 Distribution by counties: Bruce, Cochrane, Dufferin, Durham, Essex, Frontenac, Grenville, Haliburton, Hastings, Kent, Lanark, Leeds, Lennox, Muskoka, Nipissing, Peel, Renfrew, Simcoe, Timiskaming, Victoria, Wellington, York. Flower records: Amelanchier, Barbarea, Cornus, Crataegus, Euphorbia, Fragaria, Hieractum, Lepidium, Malus, Malva, Melilotus, Nasturtium, Potentilla, Prunus, Rhus, Rubus, Salix, Solidago, Taraxacum. 170 Flight period based on our collections: April to September. Size variable, brassy, abdomen concolorous and densely pubescent. Common almost everywhere with populaticns reaching large numbers around nesting sites in open sandy dunes where they nest gregariously. Males appear from early July to August. Dialictus rohweri (Ellis) 9¢ Distribution by counties: » Bruce, Dufferin, Durham, Elgin, Frontenac, Grenville, Haliburton, Kent, Lanark, Leeds, Lennox, Middlesex, Peel, Simcoe, Timiskaming, Victoria, Wellington, York. Flower records: Amelanchier, Barbarea, Crataegus, Hrigeron, Fragaria, Hieracium, Malus, Melilotus, Potentilla, Prunus, Ranunculus, Raphanus, Rhus, Rubus, Salix, Sisyrinchium, Solidago, Taraxacum. Flight period based on our coilections: May to September. Large, greenish. A common gregarious bee in southern and central Ontario, rare in the northern districts. Nests were found on southern ex- posed slopes hidden among Hieraciwm and grasses. The main shaft is up to ten inches long, lateral branches one to two inches in length termin- ating in lined horizontal cells. Males appear in July and are numerous until September. The description of the previously unknown male is being published soon (Knerer and Atwood, 1962). Dialictus sandhouseae (Michener) 9 Distribution by counties: Cochrane, Timiskaming. Flower records: Anaphalis, Epilobium, Prunus, Salix, Solidago. Flight period based on our collections: May to September. Small greenish with chestnut-coloured abdomen. This species was previously known only from its male (Knerer and Atwood, unpublished data). Its distribution on the continent is characteristically boreal. It is common north of the 47th parallel in Ontario and Minnesota and was ori- ginally described from material collected near Florissant, Colorado. No details on life history. Dialictus solidaginis Mitchell J One record exists for Kenora (Mitchell, 1960). The female and the life history are unknown. No specimens are in the authors’ collection. Dialictus tegularis (Robertson) 9° Distribution by counties: Essex, Kent, Muskoka, Ontario, Wellington, York. Flower records: Allium, Euphorbia, Lepidium, Melilotus, Salix, Smilacina, Solidago. Flight period based on our collections: April to September. Small, greenish with large punctate tegulae. Sparse distribution throughout, absent in northern parts. No details on life history. Dialictus unicus (Sandhouse) @ Distribution by counties: Essex. Flower records: Melilotus. Flight period based on our collections: July and August. Medium, greenish bee confined to Lake Erie region. No data on life history. 171 Dialictus versans (Lovell) 93 Distribution by counties: Algoma, Cochrane, Durham, Haliburten, Leeds, Muskoka, Peel, Sud- bury, Timiskaming, Victoria, York. Flower records: Amelanchier, Anaphalis, Barbarea, Epilobium, PRiGdee Ledum, Prunus, Ranunculus, Rosa, Rubus, Salix, Solidago, Taraxacum, Trifolium. Flight period based on our collections: May to September. Dark green, medium sized bee. More abundant in the northern parts of the province. Nothing known of its life history. Dialictus versatus (Robertson) @ Distribution by counties: Elgin. Flower records: Solidago. Flight period based on our coilections: August. Medium sized, brassy-green. One record only. Michenee (1956) de- scribes small dense groups of nests of this species during a study on the behaviour of subsocial halictine bees. Dialictus vierecki (Crawford) Distribution by counties: Essex, (York). Flower records: Lepidium, Melilotus. Flight period based on our collections: June to August. Perhaps the smallest halictine bee in the province. Brassy-green with an orange abdomen like D. pictus with which it shares its southern habi- tat. A series of females was collected near Torento fifty years ago but we have been unable to find it at the present time. Dialictus viridatus (Crawford) 9 — Dialictus viridatus (Crawford) ¢ (=lepidus Mitchell) new synonymy Distribution by counties: Cochrane, Haliburton, Kenora, Leeds, Muskoka, Nipissing, Sudbury, Victoria. Flower records: Amelanchier, Anaphalis, Apocynum, Salix, Solidago. Flight periods based cn our collections: May to September. Medium sized green bee more abundantly present in northern parts of the province. Atwood (1933) observed large colonies in a railway embank- ment in Nova Scotia and described the nest structure. Dialictus zephyrus (Smith) 9J¢ Distribution by counties: Bruce, Durham, Halton, Kent, Lanark, Leeds. Middlesex, Muskoka, Peel, Renfrew, Simcoe, Wellington, York. . Flower records: Amelanchier, Aster, Barbarea, Malus, Melilotus, Rhus, Salix, Scilla, Solidago, Taraxacum. Flight period based on our collections: April to September. Medium sized, greenish bee abundant along streams and lakes where numerous nests were observed in sand banks. There is great variation in size within the species. Males appear in great numbers late in July and vanish in October. Rau (1922, 1926) described large colonies in the banks of lakes. Bur- rows were oriented horizontally and guards were present at the entrances. He also observed thousands of males flying over nesting areas in fall. 172 ER ae) bere fet eM cer, ate See Fx eats eee > * . Genus AGAPOSTEMON Guerin-Meneville This genus is represented by four species whose heads and thoraces are brilliant green in color; abdomens may be concolorous or dark with pale transverse bars. Size ranges from 9-11 mm. Representatives differ from other related genera by the length of the hind tibia which is equal in length to the entire tarsus. Agapostemon radiatus (Say) 9° Distribution by counties: Brant, Carleton, Dufferin, Durham, Essex, Hastings, Huron, Kent, Lambton, Lincoln, Middlesex, Muskoka, Northumberland, Perth, Simcoe, Victoria, Wellington York. Flower records: : Barbarea, Fragaria, Hypericum, Impatiens, Malva, Melilotus, Ranun- culus, Rhus, Rosa, Rubus, Salix, Solidago, Taraxacum. Flight period based on our collections: April to October. A large, bright green or rarely blue bee common in central and sou- thern Ontario. It resembles A. texanus very closely, differing by the coarse sculpturing of the scutum. Rau (1934) observed nesting activities in a bank of fine sand. Agapostemon splendens (Lepeletier) ?¢ Distribution by counties: Bruce, Durham, Essex, Grey, Kent. Flower records: Fragaria, Malva, Melilotus, Rubus, Salix, Smilacina, Taraxacum. Flight period based on our collections: May to September. Largest bee in this genus; bright green with inftumate wings. There are more records from the southern counties and none from the area of the Canadian Shield. Agapostemon texanus texanus Cresson 9¢ Distribution by counties: Algoma, Brant, Bruce, Carleton, Dufferin, Durham, Essex, Glengarry, Grenville, Lanark, Leeds, Middlesex, Muskoka, Simcoe, Wellington, York. | Flower records: Amelanchier, Antennaria, Barbarea, Cirsium, Crataegus, Erigeron, Fragaria, M elilotus, Potentilla, Rhus, Rosa, Rubus, Solidago, Tragopogon. Flight period based on our collections: May to September. Range somewhat similar to that of A. radiatus. No data on biology. Agapostemon virescens oe) od Distribution by counties: Carleton, Dufferin, Durham, Essex, Frontenac, Glengarry, Hastings, Kent, Lanark, Leeds, Lincoln, Middlesex, Peel, Prince Edward, Victoria, - Wellington, York. Flower records: Aster, Barbarea, Centaurea, Cichorium, Cirsium, Echium, Erigeron, Meracum, Impatiens, Melilotus, Potentilla, Rhus, Rubus, Sisyrinchium, Solidago, Taraxacum. Flight period based on our collections: May to September. Large, differs from all other bees in this genus by its black, fasciate abdomen. Common in southern and central Ontario. Nests were observed in sandy banks, railway embankments and among high grass on a shaded L173 slope. Nests characteristically open into tumuli of loose material, which sometimes reach a height of four inches. Shafts up to two feet long run horizontally, sessile cells are constructed along its course at irregular in- tervals. A food preference for Rhus seems to exist in our area. Genus AUGOCHLORA Smith There is only one species of this neotropical genus in Ontario. The bee is brilliantly green or blue and differs from most other genera by its preference for logs or trees as nesting sites. Augochlora pura pura (Say) 2 Distribution by counties: Essex, Grenville, Haliburton, Kent, Leeds, Lincoln, Middlesex, Mus- koka, Sudbury, York. Flower records: Barbarea, Crataegus, Hydrophyllum, Impatiens, Lepidium, Malva, Melilotus, Rubus, Smilacina, Solidago. ~ Flight period based on our collections: May to September. Medium sized, bright green or blue. Construction of nests was report- ed previously in decaying heart wood of oak and hickory (Say, 1837). Field observations in southern and eastern counties in Ontario showed colonies in three additional trees, Acer, Fraxinus, and Tilia. The utiliza- tion of tunnels of woodboring insects in fallen logs of mavle was observed in Point Pelee National Park. The bee has frequently been confused with Augochlorella striata (Provancher) from which it differs by the shape of its mandibles and details in its venation. The biology of this species has recently been studied by Stockhammer (1961). : Genus AUGOCHLORELLA Sandhouse The genus is represented by one species only which resembles Augo- chlora but differs from it through its smaller size, morphological details mentioned under Augochlora, the use of soil as situation for nest construc- tion rather than decaying wood. The biology of this genus has recently been studied by Ordway (1961). Augochlorella striata (Provancher) 9°¢ Distribution by counties: Bruce, Carleton, Dundas, Dufferin, Durham, Essex, Frontenac, Glen- garry, Grenville, Grey, Haldimand, Haliburton, Halton, Hastings, Kent, Lambton, Lanark, Leeds, Lincoln, Muskoka, Nipissing, Ontario, Peel, Simcoe, Sudbury, Victoria, Wellington, Wentworth, York. Flower records: Antennaria, Barbarea, Carduus, Cornus, Crataegus, E'rigeron, Eu- phorbia, Fragaria, Hieracium, Hypericum, Impatiens, Lepidium, Malus, Malva, Melilotus, Onopordum, Prunus, Ranunculus, Rhus, Rubus, Rudbec- kia, Salix, Smilacina, Solidago, Sonchus, Taraxacum, Tragopogon, Wald- stewmia. : Flight period based on our collections: April to September. ; The smallest of the bright green sweat bees. Abundant especially in southern and central Ontario. Nests are usually constructed on southern exposed slopes among dense vegetation. The shaft has a turret-like ex- tension projecting up to one inch above the soil level. Cell clusters are constructed in the floor of expanded burrows. Males appear in August and September, preceding the fall females by one to two weeks. 174 Genus AUGOCHLOROPSIS Cockerell One species occurs in this province representing the only northern infiltration of a primarily trop.cal genus of brilliantly colored bees, rec- Ts by the large tegulae and paruly green legs. Nests are usually built in the soi Augochloropsis Heretics metallica (Fabricus) 9% Distribution by counties: Carleton, Durham, Essex, Frontenac, Kent, Lanark, Leeds, Middle- sex, Muskoka, Peel, Peterborough, Sudbury, Victoria, Wellington, York. Flower records: Barbarea, Cornus, Crataegus, Erigeron, Fragaria, Hieracium, Im- patiens, Malus, Melilotus, Potentilla, Rhus, Rosa, Rubus, Salix, Sisyrin- chium, Solidago. Flight period based on our collections: May to September. Medium sized bright greenish or bluish bees with enlarged tegulae. Never very abundant. Michener and Lange (1959) give detailed accounts of nest construction behaviour of neotropical representatives of this genus. Acknowledgments The research on which this paper is based has been supported by grants from the National Research Council, Ottawa and the Canadian Na- t.onal Sportsmen’s Show. These grants are gratefully acknowledged; without them it would have been impossible to even start these studies. We also wish to thank Dr. T. B. Mitchell for the loan of material and for taking the time to listen to our problems and to advise us on many un- ‘certain points; the new associations of sexes presented here have been possible only through his help. Material in the Canadian National Collection at Ottawa, the Ontario Agricultural College, the Royal Ontario Museum, Toronto and the United States National Museum at Washington has been examined with the per- mission of the officials of these institutions, to whom we are grateful. Finally, we wish to thank the officers in charge of the National and On- tario Provincial Parks for permission to collect within park boundaries. Literature Cited AtTwoop, C. E. (1933). Studies on the Apoidea of western Nova Scotia with special reference to visitors to apple bloom. Canad. J. Res. 9: 443-459. KNERER, G. and AtTwoop, C. E. (1962). A description of the males of Dialictus laevissimus (Smith) and Dialictus rohweri (Ellis). Canad. Ent. In Press. MICHENER, C. D. Aten The evolution of social behaviour in bees. Proc. tenth Intern Congr. Entomol. 2: 441-447. MICHENER, C. D. op LANGE, R. B. (1959). Observations on the behaviour of Bra- zilian Halictid Bees (Hymenoptera, Apoidea) IV. Augochloropsis. Amer. Museum Novitates 1924. MICHENER, C. D. and WILLE, A. (1961). The bionomics of a primitively social bee, Lasioglossum inconspicuum. Sci. Bull. Univ. Kansas 42: 1123-1202. MITCHELL, T. B. (1960). Bees of the Eastern United States. Tech. Bull. North Carolina agric. Exp. Sta. Vol. 1, No 141 ORDWAY, ELLEN (1961). The biology of Awgochlorella, a green sweat bee in Kansas. Proc. North Central Br., ent. Soc. Amer. 16: 17. PackaArp, A. S. (1868). The home of the bees. Amer. Nat. 1: 364-377. Rav, P. (1922). Ecological and behaviour notes on Missouri insects. Trans. St. Louis Acad. Sci. 24: 1-72 (1926). The ecology of a sheltered clay bank: a study in insect sociology. Trans. St. Louis Acad. Sci. 25: 157-278. 175 Re, | Fat, A Le eS ee ey =F } 3 x (1934). Notes on the behaviour of certain solitary and social bees. Trans. St. Louis Acad. Sci. 28: 219-224. SAY, T. (1837). Description of North American Hymenoptera. Boston J. Nat. Hist. 1: 395. STOCKHAMMER, K. A. (1961). Aspects of the life-history of the sweat bee, Augochlora p. pura (Say), Proc. North Central Br., ent. Soc. Amer. 16: 17 Accepted for publication April 30, 1962 SEROLOGICAL ASSESSMENT OF SPIDER PREDATION ON THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (CLEM.) (LEPIDOPTERA : TORTRICIDAE)’ B. G. LOUGHTON and A. S. WEST Department of Biology, Queen’s University, Kingston, Ontario Introduction The ecology of the spruce budworm, Choristoneura fumiferana (Clem.) has been the subject of intensive study in New Brunswick for a number of years. This work has resulted in the production of life tables by Morris and his co-workers (1954) which analyze the effect of various mortality factors acting on the spruce budworm. One of these factors which has been difficult to assess is predation, largely because there is seldom any record of the predatory event taking place. : Morris (1957) has pointed out that although notable progress in ecological studies has been made with such difficult vroblems as the measurement of mortality caused by avian, mammalian and invertebrate predators, life tables generally show some residual mortality that can’t be attributed to a particular factor. Such is the case for life tables on the spruce budworm. : Studies of spiders were suggested when it was found that they con- stitute approximately 90 per cent of the total invertebrate predator popu- lation. From our studies it appears that in the spruce-fir forests of New Brunswick, spider populations may be as high as 250,000 per acre. We have been able to make some contribution to the knowledge of spider predation on the budworm by the use of serological techniques. Essentially, by means of the precipitin test, we have examined the contents of the predator’s gut to determine whether or not it has fed on the bud- worm. The advantage of the serological technique lies in the fact that the environment is not manipulated prior to the sampling, as is the case in radio-active tagging, and that the collected predators can be killed and stored until it is convenient to test them for the presence of the host. The value and reliability of the serological method have been established previously in our laboratory (Downe and West, 1954; Hall et al, 1953). This paper is a brief summary of our studies. A more detailed re- port has been submitted as a contribution to a monograph on the spruce budworm (In Preparation). Serological details not pertinent to this sum- mary are to be published in a separate paper. 1From a thesis by the senior author presented to the Faculty of Arts and Science, Queen’s University, in partial fulfillment of the requirements for the degree of M.Sc., October, 1961. These studies were supported by a Canada Department of Agriculture Extra-mural Research Grant (EMR-97). Proc. Entomol. Soc. Ont. 92 (1961) 1962. 176 Methods and Results Antisera Antisera to several larval stages and to eggs of the spruce budworm were prepared in rabbits |by standard procedures. The collection of first and second instar larvae and of eggs in sufficient quantity was a difficult task. The anti-larval sera produced were found to cross-react with ex- tracts of larvae of the closely related black-headed budworm (Acleris variana Fern.) and Zeiraphera spp. Although these cross-reactions could be eliminated by absorption with the appropriate antigens, the resulting antisera were less powerful in detecting the presence of the budworm in - spider specimens. In those areas where spider collections were made during the present study, the black-headed budworm and Zeiwraphera larvae oc- curred in very low numbers as compared with spruce budworm popula- tions. The possibility of an occasional cross-reacticn was ignored in favour of having more powerful antisera. Collection of spiders Initially, spiders were collected by using a pole pruner to clip indi- vidual branches which were then beaten over a mat in order to dislodge the spiders (Morris, 1955). Subsequently it was found that felling entire trees provided an adequate sample of the spider fauna and was less time- consuming. Collections were made throughout the season at semi-weekly intervals whenever possible. Spiders were placed individually in vials and transported to the laboratory where they were identified (at least to the family level) and used in laboratory studies or killed by cyanide, dried and stored for serological examination. Serological tests The standard precipitin test was used to detect the presence of bud- worm antigens in spiders. Spiders were extracted individually in saline and tested against appropriate antisera. Spiders collected early in May were tested with an antiserum prepared against Ist- and 2nd- instar bud- worm larvae. When the later instars were present in the field an anti- Ath-and 5th-instar serum was used. An anti-egg serum was used only to test mites, since spiders will not attack immobile prey and in laboratory tests never ate eggs. Spiders collected laie in the summer, when the newly hatched larvae were present, were tested with an anti Ist- and 2nd- instar serum. Laboratory studies In the laboratory, spiders were fed on budworm larvae and starved for recorded periods of time before being killed and tested. These stu- dies (“known-feedings’’) provided information on the rate of. digestion of the budworm meal by the spider and the limits of detection by the precipitin test. When spiders fed on a 4th- instar larva, the budworm proteins could be detected regularly for four or five days and for a maximum of eight days. A meal of a 1st- or 2nd- instar larva could be detected regularly for one day and a maximum of three days. In feeding capacity tests it was found that a spider commonly fed daily on a budworm larva, but occasionally periods of as much as six days elapsed between feeds. Feeding was related to size of larva offered. Most spiders would feed on a 4th- instar larve every third day, while 1st- instar larvae were consumed at one cr two day intervals. When more than one larve was present in the test vial, feeding capacity was greater, par- 177 ticularly for the small larvae. As might be expected considerable variation in feeding capacity was recorded among individual spiders even of the Same species and size class. | i It is realized that results of laboratory tests do not necessarily indi- cate field activity. However, it appears that during the period when 4th- instar or older larvae are present in the field, and under conditions of high budworm populations, if a spider has fed on a budworm larva this feeding would be detected in most cas2s. When younger larvae are present, the detection is much less certain, although the shorter detection time may be offset partially by the probable tendency to feed more frequently. “Known-feeding”’ and feeding capacity tests were also made with mites and budworm eggs. Budworm egg material could be detected in a mite for only 24 hours after feeding. Mites consumed an average of 0.7 eggs per day and a maximum of five eggs in one day. Commonly two to three eggs were eaten at one feeding and feedings occurred at two or three day intervals. It was concluded that the efficiency of the precipitin test in detecting mite predation on ergs was of the same category as for spider predation on small larvae. Abundance of host material and fre- quency of feeding will strongly condition the probability of obtaining a positive precipitin test. Tests on field-collected spiders and mites Assessment was made primarily on collect.ons of spiders and mites from the Fredericton, New Brunswick area, at Taymouth in 1959 and Doak in 1960. Collections made at Green River in 1960 did not provide any positive information because of the very low level of budworm popula- tions. Results of precipitin tests indicated: (1) a functional response of spider predation to budworm populations, (2) a seasonal pattern of pre- dation, (8) the relative importance of various spider families and (4) gave a probable explanation of previously unknown mortality. | (1) One positive test was obtained on 600 spiders collected at Green River in 1960 when the budworm population was recorded as 0.08 larvae/ 10 sq. ft. of foliage. Twenty per cent of 1107 spiders collected in 1959 gave positive tests. The budworm population was shown by a record of 433 egg masses/100 sq. ft. of foliage in 1958. 965 tests were made on spiders col- lected in 1960. Only eight per cent of the tests detected budworm material in the spiders. This level of predation was correlated with a 1959 egg mass population of 156/100 sq. ft. of foliage. (2) The seasonal pattern of predation was well marked during the 1959 season, but less evident during the 1960 season when the budworm population was lower. In 1959, during the period when larvae were emerg- ing from their hibernaculae, 20% of the spiders had fed on budworm. This figure dropped to 4% during the period of bud and needle mining, but rose to 20% again as the larvae emerged from mines at the end of May. The proportion of positive tests for individual collections varied greatly, ranging as high as 59%. These variations are explained in part by the small size of some of the samples and also by the effects of weather on spider activity. During damp weather spiders are relatively inactive. A steady predation level of about 20% was maintained during the last half of June in spite of the decreas:ng numbers of larvae. This event is probably explained by increased activity of the larvae, thus attracting spiders more readily, and by increased predation by the dominant species, Grammonota pictilis (O. P. Cambridge) (Micryphantidae). Most spiders 178 overwinter as eggs or immature stages. In the laboratory immature G. pictilis would not attack 4th- stage and larger budworm larvae. With the aproach of maturity in the field, it appears that larger larvae were preyed on. As indicated earlier, spiders attack only moving prey and therefore did not feed on eggs. Red mites were, however, very abundant. In 1959, 22% of a sample of 390 mites were found to have fed on budworm eggs; in 1960, for a smaller sample of 109 mites, the figure was 24%. In 1959, following egg hatch (late July), spider perdation returned to about the previous level. 26% positive tests were recorded. However, the pattern of predation was altered, reflecting a change which began during the latter part of June. During the first half of June significant levels of predation were recorded for only a few spider families; later in the season significant predation by most spider families was recorded. (3) Two broad categories of spiders commonly recognized are the web-spinners and the hunting spiders. In the former group the following families were recorded: Agelenidae, Amaurobiidae, Araneidae, Dictynidae, Linyphiidae, Micryphantidae, Tetragnathidae, Theridiidae and Ther:do- somatidae. Families of the latter group were: Clubionidae, Gnaphosidae, Lycosidae, Salticidae and Thomisidae. Comments on the relative impor- tance of a few of these families, as deduced from relative abundance and results of precipitin tests, follow: The Micryphantids (particularly mature forms) are perhaps most important as a result of their preponderance in the forest environment. In the Fredericton area, the Micryphantid G. pictilis might be said to characterize the spider fauna; in contrast, in the Green River area of northern New Brunswick, another Micryphantid, Ceraticelus atriceps (O. P. Cambridge), is the dominant species. The importance of the Micryphan- tidae may be related to the fact that in addition to spinning webs they sometimes search for prey. The Theridiidae were the most efficient predators, based on the per- centage of individuals which gave positive tests. Laboratory studies sub- stantiated this conclusion. Immature Theridiids can attack large budworm larvae successfully, an exception to the general rule. The Salticidae (particularly Metaphidippus spp.) appear to be impor- tant predators of all stages of budworm larval develoment. The Thomisi- dae (Philodromus spp.) occur in large numbers, but are not as effective predators as the Micryphantidae. Dictynids are relatively common but attack only Ist- and 2nd- instar budworm larvae. Linyphiids appear to be found more frequently in old-field spruce areas and are possibly more successful predators on the younger larvae. (4) The studies reported can only be considered as preliminary, but the groundwork has been laid for more extended work in the future. It is established that spiders may exert a significant infiuence on budworm populations. This predation is regarded by R. F. Morris and his co-workers as at least helping to explain mortality which was previously unaccounted for. Future studies will establish more exactly the role of spiders as pre- dators of the spruce budworm. Acknowledgments We are indebted to Dr. R. F. Morris and other members of staff of the Forest Biology Laboratory, Fredericton, N.B. for assistance through- out these studies, to Mr. C. C. Derry who conducted preliminary studies in 1958 and to Mr. Robert DeBoo who served capably as a student assistant 79 during three summers. Dr. J. C. B. Choudhuri, at the time a National Re- © search Council of Canada post-doctorate fellow, did much of the prelimin- ary preparation of a spider species list. Dr. Choudhuri’s identifications were checked by Dr. W. J. Gertsch of the American Museum of Natural History. Literature Cited Downs, A. E. R. and WEsT, A. S. (1954). Progress in the use of the precipitin test in entomological studies. Canad. Ent. 86: 181-184. HALL, R. R., DOWNE, A. E. R., MCLELLAN, C. R. and WEsT, A. S. (1953). Evaluation of insect predator-prey relationships by precipitin test studies. Mosquito News, 18: 199-204. Morris, R. F. (1955). The development of sampling techniques for forest insect defoliators, with particular reference to the spruce budworm. Canad. J. Zool. 33: 225-294. Morris, R. F. (1957). The interpretation of mortality data in studies on population dynamics. Canad. Ent. 89: 49-69. Morris, R. F. and MILLER, C. A. (1954). The development of life tables for the spruce budworm. Canad. J. Zool. 32: 283-301. (Accepted for publication March 16, 1962) NOTES ON MORTALITY FACTORS AFFECTING THE RED-BANDED LEAF ROLLER, ARGYROTAENIA VELUTINANA (WLKR.), (LEPIDOPTERA : TORTICIDAE) IN AN UNSPRAYED APPLE ORCHARD IN ONTARIO‘ A. HIKICHI Entomology Sub-Laboratory, Research Brand, Canada Department of Agriculture, Simcoe, Ontario Probable causes of population changes of the red-banded leaf is Argyrotaema velutinana (Wlkr.) over the past fifteen years in apple or- chards of Quebec (Paradis, 1956), and northeastern North America (Clancy and Pollard, 1948; Glass and Chapman, 1949; Gould and Ham- stead, 1948; Harman, 1948) have been advanced but none completely ex- plain the phenomenon in Ontario. To investigate further the causes of outbreaks of this pest on apple in Ontario, observations on A. velutinana were carried out in 1960 in an untreated apple orchard in Norfolk County. The orchard, abandoned in May of that year following an early season spray of lime sulfur, was heavily infested with red-banded leaf roller in 1959, when spray applications were made to control insect pests and apple scab, Venturia inaequalis (Che.) Wint. This paper reports results of this study. ) Observational Data Observations on A. velutinana in the study orchard were started on May 25, 1960, when the species was in the egg stage. Egg masses were plentiful on the larger limbs of the trees following oviposition by adults of the overwintered generation in early May. About two per cent of the 100 egg masses examined were parasitized by Trichogramma minutum Riley ; the remainder were viable. The foliage on the trees was heavily infected 1Publication No. 30, Research Laboratory, Research Branch, Canada Department of Agriculture, Vineland Station, Ontario: Entomology Sub-laboratory, Simcoe, Ontario. Proc. Entomol. Soc. Ont. 92 (1961) 1962. 180 with ‘primary’ apple scab at this time. By June 8, when the eggs were hatching, the foliage was almost completely covered with ‘secondary’ scab lesions that made the leaves unsuitable for larval feeding. As a result, more than 90 per cent of first-generation larvae present on the foliage from June 8 to July 6 were estimated to have migrated to herbaceous plants of the orchard undercover, where they fed principally on curled dock, Rumex crispus L. By July 6, more than 60 larvae could be collected per man-hour from the ground vegetation. Shortly thereafter, many of the larvae, particularly those on the ground, were found to be infected with a disease, later identified as a virus disease of the granulosis type. In early August second-generation larvae of A. velutinana were very scarce on the foliage of the trees and on ground vegetation and the latter was in poor condition following prolonged drought. Larvae were difficult to find during late summer and early fall and by October only 212 had been collected at a rate of about seven per man-hour from both tree foliage and ground vegetation. Of the 212 collected, 93 showed the typical symp- toms of granulosis disease and 23 were parasitized by Phytodietus an- nulatus (Prov.). The remaining 96 larvae were placed on scarlet runner bean plants growing under fluorescent lights in the laboratory. Sixty- eight eventually showed symptoms of the granulosis disease, 45 before and 23 after pupating. Twenty-eight larvae pupated without showing disease symptoms and yielded four undersized moths and four parasites. Observations made in the study orchard in the spring of 1961 showed moths to be rare and meticulous examination of tree limbs yielded only one egg mass. : Conclusions These observations suggest that the combined effects of deterioration of host plant foliage, disease, drought, and parasitism were largely re- sponsible for decreases of A. velutinana populations from epidemic to endemic levels during the period of study. Of the factors observed, disease and drought appeared to have been the most important. The incidence of disease was higher in the abandoned study orchard than at any time pre- viously observed in commercial orchards of Norfolk County. The symptoms of the disease on larvae and pupae of the red-banded leaf roller were simi- lar to those reported by Schoene and Sibold (1952). These observations further suggest that increases in populations of the pest in recent years may be due mainly to the improved foliage of apple trees that resulted from better scab control and from improved cultural practises. Of the mortality factors observed, probably only disease and drought might be significant in reducing populations of A. velutinana in well-tended commercial apple orchards of Norfolk County. Acknowledgments I am grateful to staff of the Entomology Research Institute, Research Branch, Canada Department of Agriculture, Ottawa, for identifying the parasites and to Dr. R. D. Bird of Insect Pathology Research Institute, Canada Department of Forestry, Sault Ste. Marie, Ontario for identifying the disease. I am also indebted to Mr. H. R. Boyce, Research Station, Re- search Branch, Canada Department of Agriculture, Harrow, Ontario, and Dr. E. J. LeRoux, Research Laboratory, Research Branch, Canada De- partment of Agriculture, St. Jean, Quebec, for critically reviewing the manuscript. 181 Literature Cited CLANCY, D. W., and H. W. POLLARD. (1948). Effect of DDT on several apple pests and their natural enemies. J. econ. Ent. 41: 507-508. Guass, E. H., and P. J. CHAPMAN. (1949). Red-banded leaf roller. J. econ. Ent. 42 = 29-371. GOULD, E., and E. O. Hamstead. (1948). Red-banded leaf roller control in Western New York in 1947. J. econ. Ent. 41: 887-890. HARMAN, S. W. (1948). Red-banded leaf roller control ft Western New York in 1947. J. econ. Ent. 41: 210-213. PARADIS, R. O. (1956). Factors in the recent importance of the red-banded leaf roller, Argyrotaenia velutinana (Wlkr.) (Lepidoptera: Tortricidae) in Quebec apple orchards. Que. Soc. for Protec. of Plant. 45-48. SCHOENE, W. J., and N. O. SIBOLD. (1952). A virus disease of the red-banded leaf roller. J. econ. Ent. 4b: LO8t: (Accepted for publication February 1, 1962) SOME FACTORS INFLUENCING THE CONTROL OF THE RED-BANDED LEAF ROLLER, ARGYROTAENIA VELUTINANA (WLKR.), (LEPIDOPTERA: TORTRICIDAE) ON APPLE IN NORFOLK COUNTY, ONTARIO? A. HIKICHI Entomology Sub-laboratory, Research Branch, Canada Department of Agriculture, Simcoe, Ontario An increase in the infestation of apple by the red-banded leaf roller, Argyrotaenia velutinana (Wlkr.), particularly from 1956 to the present, has caused considerable trouble to a number of friut growers in Norfolk County, Ontario. Prior to 1956, this pest was controlled with only one application of DDD (TDE) (dichloro diphenyl dichloroethane) used in alternate years against the first generation larvae. After 1956, applica- tions had to be increased to five in some orchards. The problem was alle- viated in 1959 by adding parathion (O,O-diethyl O-p-nitrophenyl thio- phosphate) or malathion (O,O-dimethyl dithiophosphate) to DDD, or by using Guthion (O,O-dimethy]l S (4-0xo-1,2,3 benzotriazinyl-3-methyl) phos- phorothiote, alone. Despite these changes, in 1960 control was not always satisfactory. Some of the first generation larvae survived and adults from these caused further infestations in late July and August. Many theories have been advanced to explain the general increase of the red-banded leaf roller that has occurred in apple orchards in the last two decades, but meagre attention has been given to determining causes of the increases from 1956 to 1960. The work of Glass (1957) on the re- sistance of the pest to DDD offers one explanation, but failure to achieve control with Guthion treatments in 1960 in one orchard in Norfolk County 1Publication No. 31, Research Laboratory, Research Branch, Canada Department of Agriculture, Vineland Station, Ontario; Entomology Sub-laboratory, Simcoe, Ontario. Proc. Entomol. Soc. Ont. 92 (1961) 1962 182 suggested that other factors might be involved. According to Rock (1961), the possibility of DDD-resistant strains developing cross resistance to organo-phosphates cannot be neglected. In the present study, however, no investigation was made of the relation between susceptibility to DDD and to organo-phosphate insecticides. This paper deals with behavioural responses and resistance of larvae to several materials and some factors that may have contributed to fail- ures to obtain control with DDD. u Responses of Larvae to Various Spray Materials Laboratory experiments were designed to test the effect of several commonly used insecticides and the fungicide captan as irritants, causes of mortality, or as agents selecting for resistance. The experiments were conducted at a room temperature of 76° + 4°F. The sources of leaf roller larvae varied according to the technique of Hikichi and Wagner (1958), except that the Scarlet Runner bean plants were pruned to allow only the two primary leaves to remain on each plant. The area of each leaf was standardized by trimming it to a rectangle two inches by three inches. Spray suspensions were applied to all leaves to the point of “run-off” with a paint sprayer and the leaves were dried at room temperature. Two per cent orvis was added to each 1000 milliliters of spray suspension to give uniform wetting of the leaves. In the first experiment, two pounds per one hundred gallons of water of 50 per cent captan, (N-Trichloromethymercapto-4-cyclohexene-l, 2-dicarboximide) lead arsenate, 50 per cent DDT, (dicloro diphenyl! tri- chloroethane) per 50 per cent DDD, and 25 per cent sevin (1-naphthyl N- methylearbamate) wettable powders were applied to the bean leaves. Two unsprayed, untrimmed bean leaves were placed beneath each of the treated leaves. Four replicates of 20 first instar larvae from an orchard where control had been poor were placed on leaves with the dried spray residues of each treatment. Each replicate consisted of five larvae per leaf on each of the two primary leaves on two plants, a total of 20 larvae. TABLE 1. Effects of exposure of newly hatched red-banded leaf roller larvae obtained from a “problem” orchard to deposits of various spray materials on bean leaves in the laboratory. Average number established@ Treated Untreated Moved Treatment leaves leaves Dead off Captan 25 wp. 2 lb. 1975 Zp 0 0 Lead arsenate 2 lbs. 14.00 LOAD 1.00 4.75 DDT 50 wp. 2 lb. 2250 4.50 9.75 3.25 DDD 50 wp. 2 lb. #705) 1.75 2.00 15.50 Sevin 50 wp. 2 lb. .50 1.50 12.50 5.50 None 18.25 50 50 15 eS CP 0.01) 4.66 1.97 3.00 4.84 ES.) (P= 0.05) 3.66 1.42 DeAtl By! aTotals of four replicates of 5 larvae each. Table 1 shows that captan did not interfere with the establishment of larvae; Sevin caused high mortality and about 25 per cent migration; but DDD caused 75 per cent of the larvae to leave the treated surface for uncontaminated leaves. 183. In the second experiment, first instar larvae that established on leaves treated with 25 per cent captan wettable at two pounds, and 50 per cent DDT wettable powder at two pounds, and on leaves without sprays were confined singly on leaves in porous cellophane bags. Triplicate tests of 40 larvae per treatment were used. Durations of the larval Se were as follows: Materials per 100 gal. Average no. of days in larval stage Test 1 Test 2 - aT est: 3 DDT wp: 2 1b: 37.4 32.6 3500 Captan wp. 2 lb. 27.6 27.9 27.75 None 24.5 26.7 | 25.6 | EoD: (p05) — 6-5 The data shows that DDT caused a significantly greater duration of larval development than captan or no treatment. In the third experiment, records were obtained of the development of two groups of larvae, those that had become established on leaves treated with DDD at rate of one pound per 100 gallons of water and those that left treated leaves within 24 hours to establish on untreated leaves. Each larva was confined to the site of establishment by enclosing the leaf in a porous cellophane bag. No replication was made. Results were as follows: No. No. No. Duration of Per cent Larvae source used dead lost larval stage pupated (days) | Established ee 10 5 26.8 62.5 Migrated | AO S 1 25.4 85 The records show that 62.5 per cent of the larvae under continual ex- posure to DDD and 85 per cent of those with brief exposure were able to - complete development. In the fourth experiment, 100 first instar larvae from parents reared from larvae that became established on sprayed and unsprayed were used. When the larvae were exposed to leaf surfaces treated with one half pound of 50 per cent DDD wettable powder, four per cent more larvae from a population that had been reared to maturity on a DDD-treated surface became established than the larval descendants which were not previously treated with DDD. Scarcity of larvae precluded any replica- tions and it is doubtful if this difference is significant. As resistance was suspected, larvae from parental strains from DDD- treated orchards were compared with larvae from parental strains with no previous history of DDD treatment. Larvae suspected of being resistant to DDD were obtained from Winchester, Virginia, and from an orchard in which control was unsatisfactory in Norfolk County, Ontario. Check larvae were obtained from an orchard in Norfolk County where DDD had never been used. Five hundred larvae from each of the three sources were placed on DDD-treated bean leaves. 184 TABLE 2. Establishment on bean leaves treated with 50 per cent DDD @ 1 lb. of newly hatched red-banded leaf roller larvae from ‘‘problem” and ‘“non-problem” orchards. Mean percentage Source establishment@ Problem orchard (Virginia, U.S.A.) 47.8 Problem orchard (Ontario) 40.6 Non-problem orchard (Ontario) 11.0 to, (P— 0.05) = 27.28 aFive replicates of 100 larvae per treatment. Table 2 shows that establishment on the DDD-treated bean leaves of larvae from the “‘problem” orchards was significantly greater than that of larvae from the check orchard. 6000 5000 | 4000 | 3000 2000 AVERAGE NUMBER OF BUSHELS 1000 + ~ 1940 1944 1948 1952 1956 YEAR OF PRODUCTION Fic. 1. Average number of bushels of clean apples produced per grower from 1939 to 1960. Data based on the records of 80 growers with 2000 acres of apple orchards. 185 Influence of Orchard Practices A survey of a number of problem orchards in Norfolk County indi- cated that many orchard practices remained unchanged in the last decade. However, two changes were detected that possibly influenced the control of this pest. Changes in total production of apples The first change was an increase in production in the last ten years. Calculations based on the annual numbers of bushels of clean apples pro- duced by 80 growers on two thousand acres showed that the yield of good fruit in the last three years was from two to three times as great as that of 1939. The increase began shortly after the initial use of DDT in 1948, probably because superior control of orchard pests resulted. An accelerated increase began in 1955 following the widespread use of captan, possibly due to superior scab control. Increased infestation by the red-banded leaf roller coincided with the second increase in production. Table 3 shows production records and changes in the fungicide program in a seven acre orchard of Rhode Island Greening apples in Norfolk County. TABLE 3. Changes in yield of apples on seven acres of Rhode Island Greening trees from 1949 to 1960 with coincident changes in fungicides. Year Main fungicide used - No. of bushels 1949 Sulfur 3540 1950 Sulfur 710 1951 Sulfur 4735 1952 Sulfur 197 1953 Sulfur 3592 1954 Sulfur 539 1955 Sulfur 2770 1956 Captan 207 1957 Captan 3242 1958 Captan ; 4885 1959 Captan 1110 1960 Captan 3572 The data show that after 1956 the trees made a striking change from biennial to annual bearing which may have provided more constantly pours conditions for the increase of late broods of red-banded leaf roller. Changes in spray application methods The second change was that from 1950 to the present: an increased number of air blast machines came into use. Field observations indicated that heavy infestations were not confined to either low or high-volume sprayed orchards, but they were more frequent in low-volume sprayed or- chards. Accordingly, an experiment was designed to test the hypothesis that low valume spraying increased survival of red-banded leaf roller on the ground cover. Duplicate plots of 25 mature Greening trees were spray- ed as follows: with a low volume air blast machine with an additional bottom nozzle orifice to concentrate the spray on the ground; with a low volume air blast machine suplemented by a high vclume ground spray applied with a conventional spray gun; and with a low volume air blast 186 machine only. The effects of the treatments were evaluated by recording the number of living larvae and of empty webs on 200 curled dock per treatment 10 days after spraying. Results were as follows: DDD treatment No. of live No. of empty Per cent larvae webs survival Low valume with additional bottom 8 19 30 nozzle Low volume with high volume ground {é 18 28 spray Low volume Zo 40 37 The data show that more larvae survived on the ground cover where the low volume air blast sprayer was used without supplementary ground cover. Discussion The above data suggests several factors that may have been respon- sible for the general increase in the abundance of the red-banded leaf roller despite a change to more toxic insecticides and more frequent applications of sprays. The use of DDT and captan paralleled closely and may actually have caused an increased fruit and foliage production and a change from bien- nial to annual bearing in some varieties of apples. The coincident increase in red-banded leaf roller populations in spite of the use of DDT, DDD, and organo-phosphates may be due to a variety of things: increased foliage reduces penetration by sprays to the interior of the tree; the use of DDT, as shown in Table 3, increases the length of the larval stage so that spray deposits become progressively less effective unless repeated appli- cations are made. Sprays of DDD were the normal control practice but, as Shown in Table 1, probably caused many larvae to migrate from the sprayed trees to complete development on curled dock or other herbaceous plants under the trees. Table 2 shows that larvae from problem orchards were better able to establish themselves on DDD sprayed leaves than were those from non-sprayed leaves. Therefore, it appears that besides a type of behavioral resistance, manifested in the escape of larvae from sprayed leaves, there was also a true resistance that caused larvae to establish more easily on the sprayed leaves. Compounding the difficulty of control has been the inability of the air blast sprayers adequately to cover the ground foliage so as to destroy larvae that had migrated from the trees. Seemingly, the red-banded leaf roller has become a more serious threat because of changes in orchard practices, with resultant increases in tree density and cropping that have made it more difficut to obtain good spray coverage, because the use of DDD caused larvae to leave the trees to develop on unsprayed weeds beneath the trees, and because the use of DDT extended the larval stage, the consequent production of a second generation from migrating and surviving larvae varied and lengthened the period of damage. And, finally, the use of air blast machines of inade- quate covering power permitted larvae to survive on weeds under the trees and the second generation to re-infest the trees. 187 Acknowledgments I am grateful to Mr. H. R. Boyce, Research Station, Research Branch, Canada Department of Agriculture, Harrow, Ontario, for critically re- viewing the manuscript. Literature Cited GLASS, E. H. (1957). The occurrence of resistance to TDE (DDD) in the red-banded — leaf roller. J. econ. Ent. 50:5, 674. HIKICcHI, A. and H. WAGNER. (1958). A technique for rearing the red-banded leaf - roller, Argyrotaenia velutinana (Wlkr.) during the winter. Canad. Ent. 90:732. - Rock, G. C., C. H. HILt, and J. M. Grayson. (1961). Toxicity of different instars and strains of red-banded leaf roller and response of TDE-resistant strains to parathion and Endrin. J. econ. Ent. 54:1, 88-91. (Accepted for publication March 15, 1962) O OBSERVATIONS ON MATING SWARMS OF SIMULIUM VENUSTUM SAY AND SIMULIUM VITTATUM ZETIERSTEDT (DIPTERA : SIMULIIDAE) B. V. PETERSON Entomology Laboratory, Research Branch, Canada Department of Agriculture, Guelph, Ontario oe Many simullid species aggregate in flying swarms, some of which are presumed to be mating swarms. Reports of swarms of black-fly males of several species have been published by a number of North American au- thors (Bradley, 1935; Cameron, 1922; Davies and Peterson, 1956; Hocking and Pickering, 1954; Nicholson and Mickel, 1950; Peterson, 1959; Wu, 1931), but in only a few cases has actual coupling in flight been observed (Bradley, 1935; Downes, 1958; Hocking and Pickering, 1954; Peterson, 1959; Smart, 19384; Snow, Pickard and Moore, 1958). The author was fortunate in making a few observations of Simulium venustum Say and Simulium vittatum Zetterstedt mating in flight and these observations are presented below. On May 31, 1959, at 6:00 p.m. (E.D.S.T.), several small swarms of S. venustum were observed over the roadway leading into the Wildlife Research Station in Algonquin Park, Ontario. It was presumed that these were mating swarms because of the large percentage of males and because flies were seen to come together a number of times; however, mating was not actually confirmed. Intermittent light rains fell throughout the day and some biting by females occurred. By 7:00 p.m. the same evening, numerous swarms of S. venustum males had formed along the roadway at a place where it approached the North Madawaska River. The swarms were 6-15 feet above the road, and were looser and somewhat larger than those observed earlier in the even- ing, although the flies in each swarm were not numerous. The swarms were scattered along the edges or at the center of the road. No obvious swarm markers were evident unless the road itself, contrasting with the surround- ing vegetation, served this purpose as it does for certain species of Aedes mosquitoes (Downes, 1958). Observations continued until shortly after 8:00 p.m. when darkness hindered close scrutiny. The air temperature during this period was 62°F. Proc. Entomol. Soc. Ont. 92 (1961) 1962 188 The flight of the males occurred in a triple-motioned pattern. The ‘main mction of each male was an up-down “bounce” in which each fly ascended and descended 4-6 inches or more, in the manner of a bouncing ball (Fig. 1,A). As the flies ascended and descended they did so in a secon- dary, jerky, up-down fashion (Fig. 1,B). At the same time, the entire swarm freely moved to-and-fro across the road or parallel with it (Fig. 1,C). Flies were observed to pair after which they would quickly dart up and out of the swarm and disappear from view. Coupling was very evident on a number of occasions. The females apparently entered the male swarm from below and as they passed up through it were noticed and their sex explored by the males. The triple-motioned flight pattern of the males may represent a type of mating dance to elicit nearby females into the swarm for mating. Recognition of the female by the male apparently takes place in the swarm at close range by visual means and is probably cor- related to the structure of the male eye as pointed out by Davies and Peterson (1956) and Downes (1958). Also, this recognition is probably unspecific because males were observed to continually explore the sex of other males with which they came in close contact. OE IN ae = Fic. 1. Diagrammatic representation (not drawn to scale) of the triple-motioned flight pattern occurring in a S. venustum male swarm: A — the main, up-down, “bouncing” motion of each male in the swarm. B—one phase of the secondary, jerky, up-down motion of each male executed during movement A. C—the to-and-fro move- ment of the entire male swarm over a defined area. Mating swarms of S. venustwm were observed at 2:00 p.m. the next day over the roadway near the waterfall of the South Madawaska River. The sky was overcast and the air temperature was 65°F. The same triple- motioned flight pattern occurred, as was noted the day before. Swarms of S. vittatum males were observed hovering 6-8 feet above the lip of the waterfall at the outlet of Lac de la Montagne Tremblante, Quebec, on July 14, 1959. Other swarms were observed at the edge of the lake about 50 yards above the waterfall. The triple-motioned flight pattern Was again observed. From 8:00 p.m. to 9:30 p.m., many hundreds of S. vittatum females were ovipositing by dipping their abdomens to the water suriace of the lake, about 50 feet behind the lip of the waterfall. Numerous males were flying in loose swarms just above the lip of the waterfall and extending lake-ward for about 20 feet. It was observed that these males constantly explored the sex of every other male with which they came in close contact. These males would come together for a brief instant and then depart from each other at an angle of almost 180 degrees. This sex testing continued until a male would come in contact with a female enter- ing the swarm. Several very clear cases of males and females in copula 189 were seen; after the flies had paired, they left the swarm by flying almost vertically up and out of the swarm. This observation suggests that S. vittatum can mate just prior to oviposition since all the females collected from the male swarms were gravid. This occurs in both S. decorum Walk- er (Davies and Peterson, 1956) and S. arcticum Malloch (Peterson, 1959). The oviposition and male swarms both continued well into the darkness of night and could be seen when a bright light was shone on them. Literature Cited | BRADLEY, G. H. (1935). Notes on the southern buffalo gnat, Husimulium pecuarum (Riley) (Diptera: Simuliidae). Proc. ent. Soc. Wash. 37: 60-64. CAMERON, A. E. (1922). The morphology and biology of a Canadian cattle-infesting black fly, Simulium simile Mall. (Diptera, Simuliidae). Bull. Canad. Dep. Agric. 5, N.s.,. ent.- Bull2202 1-26: Davies, D. M. and PETERSON, B. V. (1956). Observations on the mating, feeding, ovarian development, and oviposition of adult black flies (Simuliidae, Diptera). Canad. J. Zool. 34: 615-655. | DowngEs, J. A. (1958). Assembly and mating in the biting Nematocera. Proc. tenth Int. Congr. Ent. (1956). 2: 425-434. HockING, B. and PICKERING, L. R. (1954). Observations on the bionomics of some northern species of Simuliidae (Diptera). Canad. J. Zool. 32: 99-119. NICHOLSON, H. P. and MICKEL, C. E. (1950). The black flies of Minnesota (Simuliidae). Tech. Bull. Univ. Minn. agric. Exp. Sta. 192: 1-64. PETERSON, B. V. (1959). Observations on mating, feeding, and oviposition of some Utah species of black flies (Diptera: Simuliidae). Canad. Ent. 91: 147-155. fe es eee Notes on the biology of Simuliwm pictipes Hagen. Canad. Ent. Snow, W. E., PickarpD, E. and Moorg, J. B. (1958). Observations on_blackflies (Simuliidae) in the Tennessee River basin. J. Tenn. Acad. Sci. 33: 5-23. Wu, Y. F. (1981). A contribution to the biology of Simulium (Diptera). Papers Mich. Acad. Sci., Arts and Letters 13: 543-599. (Accepted for publication January 31, 1962) O ADULTS OF THE EUROPEAN SKIPPER, THYMELICUS LINEOLA (OCHS.) (LEPIDOPTERA : HESPERIIDAE) TRAPPED IN FLOWERS OF THE SHOWY LADY'S SLIPPER ORCHID A. P. ARTHUR Entomology Research Institute for Biological Control, Research Branch, Canada Department of Agriculture, Belleville, Ontario Specimens of the European skipper butterfly, Thymelicus lineola Ochs., were found in the cavity of the expanded lip, or labellum, of the showy lady’s slipper orchid, Cypripedium reginae Walt., at Priceville, Ontario, where this butterfly is abundant. Three out of ten flowers ex- amined contained a total of six specimens. Four of the butterflies were dead, aparently killed by starvation, or drowned by the rainwater that partly filled some of the blooms. Evidently the butterflies crawled into the flowers but were unable to escape. The dimensions of the lip opening (Fig. 1) averaged 16 by 11 mm. whereas the wing expanse of the butterflies averaged 26 mm. and the body length 11 mm. Obviously, once inside the trapped butterflies could not fly out, and they were prevented from walking out by the downward Proc. Entomol. Soc. Ont. 92 (1961) 1962 190 fold at the edge of the lip opening and the position of the column of the flower. No other insects were found in the orchid; presumably those lar- ger than the skipper could not enter, and those smaller could escape readily. There was no indication that the plant had any toxic effect on the butterflies as some remained alive for three days when they were killed by drowning in rainwater or by starvation. Because of the relative scar- city of the plant, as compared with the vast numbers of the skipper, the effect of this control factor in reducing the butterfly population must be negligible. Fic. 1. Drawings to show relative size of skipper butterfly and showy lady’s slipper bloom: A. orchid with front of lip removed (a = column of the bloom) ; B. saggital section through flower. (Accepted for publication September 18, 1961) 0 OBSERVATIONS ON THE RELATIONSHIP BETWEEN TOBACCO CULTURE AND CYCLODIENE-RESISTANT ROOT MAGGOTS, HYLEMYA SPP. (DIPTERA : ANTHOMYIIDAE), ATTACKING FLUE-CURED TOBACCO IN ONTARIO! J. A. BEGG Entomology Laboratory, Research Branch, Canada Department of Agriculture, Chatham, Ontario Introduction Root maggots, Hylemya spp., attacked flue-cured tobacco in Ontario in increasing numbers from 1958 to 1961. The outbreaks apparently coin- cided with decreased susceptibility to cyclodiene insecticides (Begg, 1961). From 1958 to 1960, it was assumed that the usual ratio of 9 H. cilicrura (Rond.) to 1 H. liturata (Meig.) (Miller and McClanahan, 1960) was 1Contribution No. 21, Entomology Laboratory, Research Branch, Canada Agriculture, Chatham, On- tario. Proc. Entomol. Soc. Ont. 92 (1961) 1962 191 present in the tobacco soils. In 1961, all male flies collected in both tobacco- and non-tobacco-growing areas were identif.ed as H. liturata (Meig.). The absence of the seed-corn maggot, H. cilicrura (Rend.), in 1961 cannot be explained at the present time. This is a report on observations made of injury to flue-cured tobacco and the effect of tobacco culture as presently practiced in Ontario on in- festations of maggots. Although not entirely applicable, the complex usually referred to as seed maggots will be called root maggots in this article. The biology of the Hylemya spp. complex has been wee in Ontario by Miller and McClanahan (1960). Nature and Extent of Feeding Damage to Flue-Cured Tobacco in Ontario Root maggots attack flue-cured tobacco soon after planting, entering the underground stem generally near the primary root system or buried axils of leaves. Succulent transplants may be hollowed out, with the feeding tunnel extending above the soil surface. Injury is usuaily confined to surface feeding when the plants are conditioned for transplanting. Plant survival is dependent on the size and vigor of the plant in relation to the severity of attack. Sturdy plants usually overcome the feeding injury wi- thin weeks, with little external evidence of the internal injury. This sug- gests a difference in the mode of feeding between maggots and wireworms, because tobacco seldom completely recovers from the feeding injury caused by even a small wireworm. It is possible that the extraoral digestion re- ported by Hidt (1959), in Ctenicera aeripennis CENCE (Brown), is 1961 se : ALLISTON PORT HOPE -=- a . ‘ aN woopstocks '9°? __ ‘s BRANTFORD sa NG i vos 1959. LENBON is Ga Sane nae tgs iP NORFOLK 1960 COUNTY \ 1958 “—™ - CHATHAM ; 33 s Fic. 1. Flue-cured tobacco-growing districts infested with cyclodiene-resistant root maggots, Hylemya spp., in Ontario, 1958-1961 192 common to all species of Elateridae, and that the regurgitated fluid con- taining enzymes is phytotoxic to tobacco. Many tobacco plants rotted in certain infested fields in 1960 and 1961, indicating that stem rot organisms probably attack plants injured by root maggots. The combined attack by maggots and stem rots reduced stands of early-planted tobacco by 50 per cent and more in many fields. Tobacco does not ripen evenly in infested fields or in those in which the obviously injured plants have been replaced by hand. Replanting entire fields delays maturity and increases the probability of frost injury in Sep- tember. TABLE 1. Root maggot injury in flue-cured tobacco, 1958 to 1960 Number of fields Dates of planting Per cent injury? examined@ 1958 18 Before May 28 40.3 8 After May 27 Ais 1959 iS: Before May 30 63.0 5 After May 29 3.6 1960 13 Before June 1 70.8 7 After May 31 5.2 aAll fields examined had been treated with aldrin or heptachlor at 1 to 3 pounds per acre for control of cutworms and wireworms. bBased on 33 plants per field. Figure 1 shows that the tobacco-growing areas infested with root maggots increased in extent from 1958 to 1961. Increases in the degree of injury from 1958 to 1961 indicate that numbers. of larvae also increased each year (Table 1). In 1961, general observations showed that maggot numbers were probably as great as in the preceding year. Resistant strains of Hylemya spp. apparently are now well-established in most flue-cured tobacco-growing districts in Ontario. Outbreaks in four successive years suggest that continuance of the present level of cyclodiene resistance will probably result in similar infestations most years in the future. Strong and Apple (1958) stated that no satisfactory method is available for predicting when severe crop injury can be expected with a normal strain of H. cilicrura. (Rond.). Cultural Practices as Related to Damage Methods of Study The emergence traps, described by Miller and McClanahan (1960), and standard net sweeps were used to study the relationship between the alternate year, tobacco-rye rotation (Elliot and Vickery, 1959) and the Overwintered generation of adults. These observations were made in fields of first- and second-crop rye on three farms in Norfolk County. Ob- servations were also made on the habits of the flies during preparation of fields of second-crop rye for planting tobacco. The effect of plowing at different dates on the subsequent numbers of root maggots was investigated in 1960, in blocks of plots replicated four times. The plots were plowed and cultipacked in the usual man- ner on April 27, May 2, 6 and 10, and were not reworked until prepared for planting tobacco on May 24. The numbers of plants injured by maggots, and puparia recovered in wheat flour baits (Miller and McClanahan, 193 1960), were used as the criterion of effectiveness of the treatments. Seven days after planting, 10 consecutive tobacco plants in each plot were dis- sected to assess the maggot feeding injury. Immediately after planting, 10 balls of whole wheat flour dough, each about 1.5 inches in diameter, were placed about 2 inches deep in the soil near tobacco plants, in a second area, in each plot. The baits were removed after seven days and, after the larvae had pupated, the puparia were removed by washing. The baiting technique was also used to determine the effect of cul- tural operations on the subsequent numbers of maggots. In 1960, 25 baits were placed in the soil near tobacco plants in two areas of field which had been plowed and rototilled, respectively. In May 1961, the oviposition period of Hylemya spp. females was in- vestigated. Whole wheat flour baits were placed in uninfested soil, ex- posed to females for about 48 hours, and then covered with an inverted pail to exclude further oviposition. In 1960 and 1961, observations on the magnitude of the second, third and fourth generations of root maggots were attempted using the baiting technique. At about two-week intervals, from June until October, 25 baits were placed in the soil, in planted tobacco and in fall rye. Observations a. Overwintered Generation Tables 2 and 8 show that the spring flight of Hylemya spp. adults originated in fields of first-crop fall rye, sown the previous fall after harvesting tobacco. Females of the parent generations evidently oviposited in cultivated soil in preference to undisturbed soil in fields of growing rye. Adults emerged over a period of 27 days from April 27 to May 23, 1960. Cool, wet weather in 1961 delayed first emergence until May 4, and pro- longed emergence until June 5, a period of 33 days. TABLE 2. Numbers of Hylemya spp. flies collected in emergence trap pails, Norfolk County, 1960 and 1961 Total adults in 50 emergence traps Lynedock Waterford Delhi Crop of fall rye in tobacco-rye rotation Date first second2 first second? first second@ collected 1960 1961 1960 1961 1960 1961 1960 1961 1960 1961 1961 May 2 3 14 37 6 25 4 91 57 8 1 iL i 10 1 32 4 1 3 Ki, 6 48 25 6 41 15 74 44 34 16 1 4 25 2 19 5 4A 7 23 2 9 1 1 26 25 31 10 1 8 June 2 6 4 5 3 1 Totals B20 AO 14 Peedi Wot etewen a 4016) ip Of 103) F090 if aTraps were replaced on cultivated soil when rye was plowed for current crop of tobacco. 194 TABLE 3. Numbers of Hylemya spp. flies per 100 net sweeps. Norfolk County, 1960 and 1961 Flies per 100 net sweeps Date . First crop rye Second crop rye Rye Plowed 1960 1961 1960 1961 1960 1961 April 27 50 5 MAY 23 70 600 100 4 1800 15 350 5 3050 6 300 200 8 75 15 25 10 450 25 50 12 100 150 100 50 300 16 150 150 50 1 50 300 18 als 50 19 50 400 24 20 50 10 50 Preparation of fields of second-crop rye during the first two weeks in May, for planting tobacco, clearly demonstrated the attractiveness of freshly-worked soil to Hylemya spp. adults (Miller and McClanahan, 1960). Flies from fields of first-crop rye soon appeared on the cultivated soil and followed tractor-drawn equipment in swarms. Broadcast treatments of aldrin or heptachlor, applied during this period for control of cutworms and wireworms, caused no apparent mortality of the flies. Root maggot flies were also attracted to feed on exposed stalks of rye, especially in fields which had been rototilled. In 1960, on three farms, maggot injury to flue-cured tobacco was noticeably heavier in fields which had been rototilled than in those which had been plowed in the usual man- ner. On one farm, whole-wheat flour baits averaged 13.1 and 2.1 puparia after rototilling and plowing, respectively. b. First Generation In 1961, as shown in Table 4, peak oviposition occurred May 12 to 15, 8 to 11 days after first emergence of the overwintered generation of adults. This indicates that the greater number of eggs probably were laid between May 4 and 7 in 1960. In both years, cool, wet weather during the oviposition periods apparently favored survival of newly-hatched larvae from eggs deposited on or near the soil surface. Plowing tobacco land before and after peak adult emergence in 1960 had no effect on numbers of maggots or injury to flue-cured tobacco (Table 5). Survival of larvae evidently was assured by frequent rains which fell between May 6 and 24. TABLE 4. Oviposition period of Hylemya liturata (Meig.), Delhi, Ontario, 1961 Date baits exposed to females Puparia per bait@ May 5-7 0.25 May 7-10 0.30 May 10-12 0.90 May 12-15 41.95 May 15-17 10.40 May 17-19 4.40 4Based on 25 baits 195 TABLE 5. Percentages of damaged flue-cured tobacco plants and ‘numbers of puparia per 10 baits after plowing on various dates for control of root maggots, Hylemya spp., Delhi, Ontario, 1960 Date plowed — Per cent damage? Puparia per 10 baits? April 27 85.0 98.8 May 2 65.0 . 17.5 May 6 45.0 63.8 May 10 70.0 ADD, aDifferences were not significant by analysis of variance In 1958 to 1960, dates of planting the tobacco had a definite effect on the degree of maggot injury (Table 1). Tobacco planted after about June 1 was relatively free of damage. In 1961, maggots continued to hea- vily injure tobacco until about June 10. Maturity of the maggots evidently had been retarded by cool, wet weather and periodic frosts which continued until May 30, 1961. These observations show that, in certain years, root maggots can be controlled in flue-cured tobacco by adjusting the date of first planting. Early planting, however, is desirable because it decreases the probability of frost injury in September. c. Subsequent Generations No information was obtained on the magnitude of the second, third, or fourth generations of root maggots in tobacco soils in Norfolk County in either 1960 or 1961. In both years, all puparia recovered from baits placed in tobacco or rye fields were identified as the spotted root fly, Euxesta notata (Wied.). In August, 1960, baits averaged 108 puparia of this species. As far as can be determined, larvae of the spotted root fly did not attack newly-transplanted tobacco in either 1960 or 1961. Adults did not emerge in numbers until early June, and larvae were not present in to- bacco soils until the critical growth period was past. Conclusions It is very evident that tobacco culture, as presently practiced in On- tario, is conducive to heavy infestations of the injurious first generation of maggots and injury to flue-cured tobacco. Since these agronomic practices are presently considered to be largely unchangeable, it can only be con- cluded that it is impractical to control root maggots in tobacco soils by the cultural means now known. Chemical control experiments have shown that Diazinon applied as a planting-water treatment provides a high degree of protection to flue-cured tobacco from attack by resistant root maggots (Begg, 1962). Summary In Ontario, cyclodiene-resistant root maggots, Hylemya spp., attacked flue-cured tobacco in increasing numbers from 1958 to 1961. A complex of H. cilicrura (Rond.) and H. liturata (Meig.) probably occurred in 1958 to 1960. In 1961, only H. liturata was recovered in both tobacco- and non- tobacco-growing districts. The injurious first-generation larvae tunnel into the underground stems of large succulent transplants, retarding early growth. Injury is largely confined to surface scarring when plants are conditioned for planting. Plant survival is dependent on size and har- diness of transplants in relation to severity of the attack. The incidence of stem rot appeared to be high in certain infested fields. 196 Tobacco culture, as presently practiced, is conducive to heavy infes- tations of maggots and injury to flue-cured tobacco. Injury can be greatly reduced by delaying planting until after peak larval activity, but this practice would increase the probability of frost injury in September. Acknowledgements The assistance of N. N. LeBlanc and J. N. Telford, student assistants in 1960 and 1961, respectively, and the cooperation of L. 8. Vickery, Superintendent, Experimental Farm, Research Branch, Canada Depart- ment of Agriculture, Delhi, Ontario, is gratefully acknowledged. Literature Cited Brae, J. A. (1961). A note on resistant root maggots, Hylemya spp., as pests of flue- cured tobacco in southwestern Ontario. Canad. Ent. 93: 1022. Bscc, J. A. (1962). Chemical control of cyclodiene-resistant root maggots, Hylemya spp. (Diptera: Anthomyiidae), attacking flue-cured tobacco in Ontario. Tobacco Science 6: 58-61. Ent, D. C. (1959). Mode of feeding of the larva of Cteniceru aeripennis destructor (Brown) (Coleoptera : Elateridae). Canad. Ent. 97: 97-101. ELuiotT, J. M. and Vickery, L. S. (1959). Ontario flue-cured tobacco soils and their fertilizer requirements. Canada Dept. Agr. Publ. 987. MILuer, L. A. and McCLANAHAN, R. J. (1960). Life-history of the seed-corn maggot, Hylemya cilicrura (Rond.) and of H. liturata (Mg.) (Diptera: Anthomyiidae), in southwestern Ontario. Canad. Ent. 92: 210-221. STRONG, F. E. and APPLE, J. W. (1958). Studies on the thermal constants and seasonal ocurrence of the seed-corn tnaggot in Wisconsin. J. econ. Ent. 51: 704-707. (Accepted for publication March 27, 1962) -INSECTICIDAL ACTIVITY OF MANEB FORMULATIONS AGAINST THE GREENHOUSE WHITEFLY, TRIALEURODES VAPORARIORUM (WESTW.) (HEMIPTERA : ALEYRODIDAE)* Heh bOYeE Entomology Laboratory, Research Branch, Canada Department of Agriculture, Harrow, Ontario The greenhouse whitefly, Trialeurodes vaporariorum (Westw.), causes considerable economic damage in Ontario to fall and spring crops of greenhouse tomatoes, and to spring crops of greenhouse cucumbers each 1Contribution No. 38, Research Station, Research Branch, Canada Agriculture, Harrow, Ontario. Proc. Entomol. Soc. Ont. 92 (1961) 1962 ~ 197 year. In addition to the stress placed on plants by the removal of sap by large populations of the insect, sooty mold fungi grow on the honey te excreted by the nymphs and the fruits have to be washed. McMullen (1959) reported insecticidal properties of maneb* against larvae and adults of the greenhouse whitefly. As maneb is recommended for the control of several diseases of greenhouse vegetables, further ex- ploration was undertaken to determine the effectiveness of wettable pow- der and dust formulations of the material against the insect. If they were effective, the addition of insecticides to the fungicide might be eliminated and thereby simplify and reduce the cost of control. . Methods and Materials Sprays of 80 per cent maneb wettable powder (Dithane M-22, Rohm & Haas Company of Canada, Ltd., West Hill, Ont.) were applied in 1960 to a fall crop of greenhouse tomato, variety Vinequeen. For comparison, sprays of 65 per cent Zineb* wettable powder (Dithane Z-78, Rohm & Haas Company of Canada, Ltd., West Hill, Ont.) were also tested. The sprays were applied with a Sparton greenhouse sprayer (John Bean Division, Food Chemistry and Chemical Corp., Lansing, Mich.), operated at a pump pressure of 135 psi. A Trigger Tee Jet spray gun with adjustable Cone Jet nozzle (Spraying Systems Co., Bellwood, Illinois). adjusted to deliver 300 gallons per acre, was used to distribute the spray. The experimental plots, comprising three randomized blocks, in a greenhouse at the Research Station, Harrow, Ont., each had 6 rows with seven plants per row. Condi- tions of growth were similar to those in commercial greenhouses. Because of the prolonged spray schedule and the uncertainty that dead larvae and nymphs would remain on the leaves, effectiveness was adjudged on the basis of relative numbers of surviving nymphs and pupae per composite sample per plot. The sample for each plot comprised the ter- minal seven inches of six leaves taken, one per plant, from the end and centre plants of the two middle rows of each plot. The sample leaves were taken at a height of 3.5 feet from the soil surface, to coincide with the location of the most heavily infested leaves in the check plots. In experiments during 1961, pot-grown Black Valentine bean plants, reduced to one primary leaf, were placed for 24 hours in a greenhouse compartment beside Samsun tobacco plants heavily infested with green- house whitefly to permit the latter to overposit on the bean plants. Then the bean plants were removed to a different compartment and maintained at an average temperature of 74°F. For each test. eight plants were dusted with 7.2 per cent maneb dust (King Calcium Products Company Ltd., Campbellville, Ont.) and eight were left untreated te serve as checks. The dust was applied at the rate of 40 lb. per acre, with a rotary Midget Duster (Plant Products Company Ltd., Port Credit, Ont.). The dust was aplied to eggs and nymphs of several ages. Treated and untreated plants were randomized on the greenhouse bench. The effectiveness of the dust treatment was evaluated by recording the total numbers of hatched and unhatched eggs, or of living and dead nymphs, 10 days after treatment. The criterion of mortality among eggs was failure to hatch, and among the nymphs, a collapsed and discolored appearance. A correction, as re- Te by Abbott (1925), was applied to compensate for mortality in the checks. *manganese ethylenebisdithiocarbamate zinc ethylenebisdithiocarbonate 198 Results and Discussion TABLE 1. Survival of greenhouse whitefly after four applications of maneb or zineb to greenhouse tomato, variety Vinequeen in 19604 Number living nymyhs and pupae? Material and dosage of formulation per acre Per plot Mean and standard deviation 80% maneb wettable powder, 6 lb. 4 5 3 As 08 65% zineb wettable powder, 6 lb. ee oF DAZ TAD ste 50 Check 1260 1530 636° AZ = 374 aSprays applied Sept. 6, 16, 26 and Oct. 7. bRecorded October 26. Table I shows that in 1960 maneb and zineb reduced populations of greenhouse whitefly nymphs and pupae on the test plants. Maneb was markedly more effective and its use as a spray for the control of fungus diseases of the greenhouse tomato can be expected to control the insect. TABLE 2. Mortality of greenhouse whitefly eggs treated with 7.2 per cent maneb dust 40 lb. per acre Number of eggs on Average age eight bean leaves Percentage Treatment of eggs in days Alive Dead Total mortality2 Dusted 0.5 58 4216 4274 98.4 Check 0.5 3413 14 3427 — Dusted : Sed) 14 1331 1345 99.0 Check 4 2059 2 2061 — aCorrected mortality, Abbott’s method. Table 2 shows that the maneb dust caused high mortality of eggs of the greenhouse whitefly. The ovicidal action of the formulation was as effective against eggs that had developed to within 12 hours of hatching as against those that were approximately 12 hours old. TABLE 3. Mortality of greenhouse whitefly nymphs treated wih 7.2 per cent maneb dust at 40 lb. per acre Number of eggs on Average age of eight bean leaves Percentage Treatment nymphs in days Alive Dead Total mortality® Dusted 1.5» 1 2752 2753 99.9 Check 1S 1871 46 1917 = Dusted 5.5¢ 0 1699 1699 100.0 Check 5.5 1743 105 1848 = Dusted 9.54 1738 336 2095 9.1 Check 9.5 1968 MLPA 2074 — aCorrected mortality, Abbott’s method. bFirst instar nymphs. cSecond instar nymphs. dThird and fourth instar nymphs. 199 The data in Table 3 indicate that the maneb dust was very much more effective against the first and second nymphal instars of the insect than against the later ones. The pronounced effectiveness of the maneb dust against the eggs and first two nymphal instars suggest that its application in commer- cial greenhouses may give control of the pest. Repeated observations have shown moreover that spray and dust applications of maneb also kill adults to a degree that probably contributes an appreciable reduction of whitefly populations. Summary In 1960, four applications of 80 per cent maneb, or of 65 per cent zineb wettable powders as a spray, almost eliminated the greenhouse whitefly as a pest of greenhouse-grown tomatoes variety Vinequeen. In 1961, laboratory experiments showed that single applications of a 7.2 per cent maneb dust at 40 lb. per acre to primary leaves of Black Val- entine bean caused very high mortalities to eggs of several ages and to first and second stage nymphs of the whitefly, but not to later nymphal instars. Both formulations were observed repeatedly to kill rather large por- tions of adult populations. Literature Cited ABBOTT, W. S. (1925). A method of computing the effectiveness of an insecticide. J. econ. Ent. 18: 265-267. McMULLEN, R. D. (1959). Insecticidal action of ethylene bisdithiocarbamates. Nature 184: 1388. (Accepted for publication February 1, 1962) 10) BIOASSAY OF ORGANIC INSECTICIDES, IN TERMS OF CONTACT TOXICITY, TO THE VARIEGATED CUTWORM, PERIDROMA SAUCIA (HUBNER) (LEPIDOPTERA : NOCTUIDAE)’ C. R. Harris, J. H. MAZUREK and G. V. WHITE? Entomology Laboratory, Research Branch, Canada Department of Agriculture, Chatham, Ontario The variegated cutworm, Peridroma saucia (Hibner), periodically causes severe damage in tobacco fields in southwestern Ontario. Present control recommendations are based primarily on the results of field ex- periments. These results, however, are often inconclusive, because cut- worm outbreaks are difficult to predict and usually unevenly distributed. To assist in the development of control recommendations, the contact toxicity of five chlorinated hydrocarbon insecticides to fourth-instar lar- vae of P. saucia (Hbn.) was determined by bioassay. Methods and Materials The insects were reared under controlled conditions according to the procedure described by Harris et al. (1958). Bioassays were conducted using the spray tower technique described by Harris and Mazurek (1961). iContribution No. 17, Entomology Laboratory, Canada Agriculture, Chatham, Ontario. 2Deceased October 7, 1961. Proc. Entomol. Soc. Ont. 92 (1961) 1962 200 Four to six insecticide molar concentrations were used for each bioassay. These concentrations were known to cause from 20 to 85 per cent mortality of the test insects. Duplicate groups, each containing 10-fourth-instar cutworms, were used with each insecticide concentration. Tests with the “standard” insecticide, dieldrin, were included with assays on each insecti- cide tested. Test insecticides included endrin, aldrin, heptachlor, and DDT. Two solvent controls (9:1 acetone-olive oil) were included with each bio- assay. After being sprayed the larvae were placed, for observation, in waxed paper cups 21% inches in diameter and 214 inches high, containing a two-inch layer of moist, sandy loam. Half-inch cubes of Beck’s diet (Beck et al., 1949) were supplied as food. The observation containers were placed in an incubator at 80+1° F. and 75+5 per cent relative humidity. Mortality counts were made 48 hours later according to the method de- scribed by Harris and Mazurek (1961). Corrections for natural mortality were made using Abbott’s formula (Abbott, 1925) and modified weighting coefficients (Finney, 1952). The dosage-mortality data were analyzed according to the procedure outlined by Finney (1952). Toxicities of the test insecticides relative to the “standard” insecticide, dieldrin, were cal- culated as described by Harris and Mazurek (1961), arbitrarily assigning dieldrin a value of 1.00. Results and Discussion Analysis of the data indicated that the slopes of the regression lines for endrin’, aldrin’, heptachlor*, and DDT” were not significantly different from the slopes obtained with the dieldrin’ “standard”. If the slopes of the regression lines had not been parallel it would have been necessary to estimate the relative toxicities of the test materials, as compared to the dieldrin “‘standard”’, at both the 50 and 95 per cent mortality levels (Harris and Mazurek, 1961). With parallel slopes, however, it was possible to obtain an accurate estimate of the relative toxicity at the 50 per cent mor- tality level (Table I). TABLE 1. Summary of-dosage-mortality data obtained from bioassay of organic in- secticides against fourth-instar larvae of the variegated cutworm, Peridroma saucia (Hubner) . : . ‘ Relative Fiducial face chicide Equation of Tegression line LD50 (x10-5 M.) toxicity limite os Test Standard Test Standard at relative Insecticide Insecticide Insecticide Insecticide LD502 toxicity Endrin 2.687-+2.049x 1.634+2.049x 13 44 3.26 5.59 & 2.20 Aldrin -0.434+3.410x -0.496+3.410x 39 41 1.05 135.& 0:83 Heptachlor OOK a2 ea lox. 22a 2 oer 55 43 0.78 1.13 & 0.49 DDT» =1.950=22.954x 0.3812--2°954x 225 39 0.17 0.25 & 0.13 aToxicities relative to “standard” insecticide dieldrin, which was arbitrarily as- signed a value of 1.00 b1,1,1-trichloro-2,2-bis (ychloropheny]l) ethane. In terms of relative toxicity, endrin»aldrin—dieldrin—heptachlor »DDT. These results were very similar to the data obtained in tests with the black cutworm, Agrotis ipsilon (Hufnagel) (Harris and Mazurek, 8Shell Chemical Company, New York, N.Y. 4Veliscol Chemical Corporation, Chicago, Ill. 5Geigy Chemical Corporation, Yonkers, N.Y. 1961). However, endrin appeared to be more toxic to the variegated cut- worm than to the black cutworm, while the reverse was true in the case of aldrin. In tests with heptachlor the regression line was not parallel to the “standard” insecticide when tested against the black cutworm, while with the variegated cutworm the regression curve was parallel to the di- eldrin standard. It would be expected, therefore, that heptachlor would be more effective for control of the variegated cutworm than for the black cutworm, since materials yielding a low slope in bioassays give less effec- tive control in the field (Begg et al., in preparation). Literature Cited AppoTT, W. S. (1925). A method of computing the effectiveness of an insecticide. J. econ. Ent. 18: 265-267. Beck, S. D., J. H. LILLy and J. F. STAUFFER (1949). Nutrition of the European corn borer, Pyrausta nubilalis (Hbn.). I. Development of a satisfactory purified diet for larval growth. Ann ent. Soc. Amer. £2: 483-496. Bece, J. A., C. R. HARRIS and G. F. MANSON. Chemical control of artificial infestations of the black cutworm, Agrotis ipsilon (Hufnagel), in flue-cured tobacco. In pre- paration. FINNEY, D. J. (1952). Probit Analysis. A statistical treatment of the sigmoid response curve. Camb. Univ. Press. 318 pp. Harris, C. R., J. A. BEGG and J. H. MAzurEK (1958). A laboratory method of mass rearing the black cutworm, Agrotis ypsilon (Rott.), for insecticide tests. Canad. Ent. 90: 328-331. Harris, C. R. and J. H. MazurEK (1961). Bioassay of organic insecticides, in terms of contact toxicity, to the black cutworm, Agrotis ypsilon (Rott.). Canad. Ent. 93: 812-819. (Accepted for publication February 12, 1962) O LABORATORY TESTS ON THE TOX'C?TY OF SOME ORGANIC INSECTI- CIDES TO THE BOXELDER BUG, LEPTOCORIS TRIVITTATUS (SAY) (HEMIPTERA : COREIDAE)’ J. H. MAZUREK, G. V. WHITE? and C. R. HARRIS Entomology Laboratory, Research Branch, Canada Department of Agriculture Chatham, Ontario Outbreaks of the boxelder bug, Leptocoris trivittatus (Say), periodi- cally bring complaints from householders in southwestern Ontario. Pre- sent control recommendations usually involve the use of chlordan, which often proves to be inadequate. Therefore, laboratory screening tests were conducted to assess the toxicity of a number of insecticides to field-collect- ed boxelder bugs. Eight insecticides were tested: aldrin’, dieldrin’, methoxychlor’, Sevin’, Diazinon*, endrin’, Dylox’, and chlordan’. Insecticide solutions containing 1Contribution No. 18, Entomology Laboratory, Canada Agriculture, Chatham, Ontario. 2Deceased October 7, 1961. 3Shell Chemical Company, New York, N.Y. 4Geigy Chemical Corporation, Yonkers, N.Y. 5Union Carbide Chemicals Company, New York, N.Y. 6Chemagro Corporation, New York, N.Y. 7Velsicol Chemical Corporation, Chicago, Ill. Proc. Entomol. Soc. Ont. 92 (1961) 1962 202 0.001, 0.010, 0.100, and 1.000 per cent analytical grade insecticide were made up in a 9:1 acetone-olive oil solvent mixture. The boxelder bugs were placed in a cold room and replications of 10 insects each (adults, unsexed) were counted into petri dishes, nine centimeters in diameter. Duplicate groups of the test insects in the petri d.shes were placed in a Potter tower (Potter, 1952) and sprayed with five-milliliter aliquots of each insecticide concentration. A 15-second spray period was allowed, using an air pressure of 15 centimeters of mercury. A settling period of 15 seconds was also allowed. After treatment, the insects were placed in waxed paper cups 214 inches in diameter and 214 inches high, which were covered with petri dish tops nine centimeters in diameter. Mortality counts were made 24 hours after the insects had been sprayed. Results of the tests are given in Table 1. TABLE 1. Contact toxicity of eight insecticides to the boxelder bug Leptocoris trivittatus (Say): Average per cent mortality a Per cent eS rs G solution i= Pe S 5 f= my S) xe iS Js i ac) i U KS & as a 5 5 Sy Ao o B S = is ire 8.x. oe aes s ose ee elie hae a 5 @AMERON, J. W. MacB. (An historical-approach) ............00.c...cccceesesececeeseeeentens q WEASON Wik: Mi (A “philosophical approach) (2:02). 00 ..i4sceetteics tastier eteedes 16 WiiSiweAn os. Moderators comments, 274.5). A ciks Sacee lee ei ieee Rac ab is Sevedaee 20 II. REVIEWS PUTMAN, WM. L. The codling moth, Carpocapsa pomonella (L.) (Lepidoptera: Tortricidae): A review with special reference to Ontario ................0.0...: 22 Harcourt, D. G. Biology of cabbage caterpillars in Eastern Ontario ............ 61 Foott, W. H. The biology and control of the pepper maggot, Zonosemata electa (Say) (Diptera: Trypetidae) in southwestern Ontario ..................... 75 II. SUBMITTED PAPERS BENEDICT, W. G. Mosquitoes in and about Windsor, Ontario ........................... 82 Cass, L. M. Control of caterpillars on late cabbage in the Ottawa Valley, WOOT ee eile OM ame eR A ae ae aC AA ALR oN RA re eee Oe Bt 85 Foott, W. H. A note on insect hallucinations affecting an elderly couple ........ 88 LAING, J. and WELCH, H. E. A dolichopodid predacious on larvae of Culex POSE OUT TE GEO) OME Prater She A aR A Sele MAR arta tn a OO eR eM een AE 89 McCLANAHAN, R. J. Food preferences of the six-spotted leafhopper, PE CROSLELESLSCU TOMS Oba) ie eae ee hens ec sth cea os Once CU OORe Aes Cone t ledger ne 90 PETERSON, B. V. Additional records of some American bat flies (Diptera: Nycteribiidae) .............., ee ANE sac RRR TI ah OD Fess Dt ean a SCCM ROAR A OE ea MRM LTR 93 Woop, D. M. Two new species of Ontario black flies (Diptera: Simuliidae).... 94 Woop, D. M., PETERSON, B. V., DAviIES, D. M., and GyorkKos, HELEN. The black flies (Diptera: Simuliidae) of Ontario. Part II. Larval identification, WitmedescEiptions: and -aillustrabions 9.0) 0s..<-. chen.) ee ks ee 99 IV. THE SOCIETY. Proceedings of the ninety-ninth annual meeting 9.0... 130 Papers read) ¢22.2.0:.5 git RA Ra i er tS so na RAEN Ve ead a eR ICR Nek BR ME ON 130 PUISHIMESS HAITI CO GICs ec Me a eet a as Pee ee in A ee aed Dice Many = a asa alae ae 133 SonmitteeTepoctsyerc.: hc ices eee EMail oles ee Ty eds A 135 FRU ICAGIOMS tee cats acre, ee eae ae ee con ein el mene See Re NNER ESR Anu fats Oe Mk eee 135 TES OT EEE IR aon ies oc teolee Ree ane DANY A cies i An THEA 1 (0A ae TLR aie SEES Nm mR RRR LL ORM GC 135 COMMOMMAMECS sents kel ere. Geena rye Tee it key. A Nit a) ciel Oh Reel 136 | ENECOYSAT EEN 0 ae kA coe is Eg 3 a UTD rene A ee eI Ae en 2 eGR ed GC 136 Ein cial re posites ti Nee he mae es e ankie Noth aa Weta ce sit ees Saar ee, nut, kar MN capa 137 FVESOLUGTONS UE. Crs er eae Sik GU Me ol ema UE. Site irn ste Rt Sag i, fea Dhaai 137 IBGOST@eMGste Pe TIZOl. been e Bian Cee Bee EEE hel de MEE ah sere RN Mio 5.9 na ea Pee lets) La) TRGSHTAG TEE WG gma a wees aE EULA EG Ay hed Ite si lls SNe avin A eM, See eae CO sn Me aise Nate Lan a OE 139 Wi, SLO 8D) OD, Gallas Maia Me a ae a Wee Re tapes Ales HA Se ake OW acs AMD SER derietee hur dE) See 142 I. SYMPOSIUM How Useful is the Basic Research Program to Economic Entomology’ BRYAN P. BEIRNE Entomology Research Institute for Biclogical Control, Research Branch, Canada Department of Agriculture, Belleville, Ontario As the other contributors to this seminar deal with the subject broadly, I will take a different viewpoint based on the example of the Belleville Institute. In effect I am rewording the seminar title as: how useful is the Belleville research programme to economic entomology? I do not feel that I have to be on the defensive in answering this question, as the pri- mary function of the Research Institutes is research on principles. Never- theless it is not difficult to demonstrate the practical value of the work at Belleville, even omitting our service responsibility to obtain biological control material and information required from abroad for application by economic entomologists against specific pest problems in Canada and which has been instrumental in reducing more than a dozen species that formerly were pests to relative insignificance from the economic viewpoint. In a university department basic research need not have an applied relationship. But in the Research Branch, which exists to improve Canadian agriculture, it usually has. The theoretical, and commonly also the actual, sequence of events is: problems arise in applied projects in the field; they are solved by basic research in the laboratory; and the results of this basic research are then applied to the field projects. With two exceptions, all the present Belleville research projects developed from problems encountered in applied control work against individual pest species. However, most, if not all, were recognized by Belleville staff rather than brought to our attention by the economic entomologists. The organization of our research programme indicates its ultimate practical bias. Three groups of research officers are each engaged in re- search on or related to one of the three main ways of applying biological control: by establishment of introduced agents; by conservation, to increase existing agents; and by augmentation, mainly with nematodes and microbial pathogens. A fourth group, that in part overlaps these, is con- cerned with the control of biting flies by means other than chemical pesticides. Then there are three further groups each engaged in research basic to that of the other four: two on population ecology and one on internal reactions of and to parasitic organisms. Summary of a paper presented at the 99th annual meeting of the Entomological Society of Ontario, Belleville, Ontario, November 14-16, 1962, as part of a seminar on how useful the basic research program is to economic entomology. Proc. Entomol. Soc. Ont. 93 (1962) 1963 It is apparent that the programme is organized to produce results of | ultimate practical application. But in fact the results have not been applied widely. There are several possible reasons for this. One is that the basic research programme at Belleville is relatively new: most of the projects were started in their present form only within the past six years, most of them within the past three or four years. Consequently some or many of them have not yet reached the stage where practical application is demonstrably feasible. Another reason is that hitherto economic entomolo- gists were too concerned with using chemical pesticides and tended to ignore the potential of biological control. However, it is hoped that the current swing of the pendulum away from over-emphasis on chemical control may rectify this. A third reason is, I suspect, that economic ento- mologists as a whole may not read basic research papers or, if they do, it may not occur to them that the results are potentially applicable to their control projects on individual pest species. Part of the blame for this may rest with the basic research men, whose publications sometimes tend to be so abstruse as to be esoteric. Despite these reasons, it is nevertheless a fact that the results of basic research in biological control have not been applied te the extent that they should by economic entomologists in Canada. I mention this because one of the Belleville research discoveries that is of much practical value was ignored in this country but widely and successfully applied in the U.S.S.R. to reduce a number of important pests. It is evident that there is a weakness in communications between economic entomologists and those engaged in basic research. We are initi- ating action to overcome this. First, when appropriate, basic research projects at Belleville will not stop when the problem is solved but will when feasible go one stage further: field tests to demonstrate that the results have a potential practical application. It is not our job to control a pest species, but to demonstrate that it could be controlled by use of new methods or approaches that we develop. Second, we are planning a series of technical bulletins that, we hope, will bridge the gap between the basic researcher and the economic entomologists by assisting and informing the latter on the feasibility, value and potential of biological control. For example, we are compiling all available information on the natural enemies of crop pests in Canada. Third, we are encouraging more frequent visits by Belleville staff to other establishments. _ The fact that we extend our official function, research on principles, one step further to demonstrate potential practical applications does not mean that we will extend further into the field of economic entomology and do research that should be done by economic entomologists. For ex- ample, while we provide information, and if necessary material from abroad, to assist in studies on the biological control of individual species of insect pests we do not normally make such studies in Canada because these fall within the province of the economic entomologists. Nor do we normally investigate the effects of chemical pesticides on specific biological control agents because evaluation of these effects, bad as well as good, is a responsibility of those who study or test those pesticides. In summary, the basic research programme at the Belleville Institute does not have to be directly valuable to economic entomology, but in practice we try to make it so within the limits of the functions and responsibilities of the Institute. My main conclusion is that results of basic research are valuable to economic entomologists if they will apply them. (Accepted for Publication: January 16, 1963) 6 How Useful is the Basic Research Program in Insect Pathology to Economic Entomology’ J. W. MACBAIN CAMERON In order to reduce the possibilities of misunderstandings, it is desirable to begin by defining the two major concepts as I have considered them in this discussion. These concepts are “basic research” and “economic en- tomology’’. Basic research in insect pathology may be regarded as embrac- ing practically all aspects of the study of pathogens affecting insects except the deliberate use of them in an attempt to control pest species. Economic entomology includes the study of any or all factors involved directly or indirectly in reducing or preventing monetary loss due to the activity of insects. | It must be realized that there are broad areas where a particular activity would be included in one or other of these definitions depending on the primary interest of the investigator at the moment. As an example, two people might conduct an experiment with a pathogen, using a par- ticular insect feeding on a particular crop. The first might be concerned to find out whether he could initiate infection by the pathogen in the insect population, and what became of the pathogen in succeeding generations, and the second to determine whether by use of the pathogen the crop could be protected from damage by the insect so that it could be sold for a reasonable profit over production costs. To put it another way, the basic research problem is approached in the spirit expressed by the mountaineer who was asked why he wanted to climb Mt. Everest—‘‘It was there!” The economic research problem of necessity includes the prospect of financial return, “‘economic” being defined in the dictionary as ‘practical’ or “utilitarian”, and we nowadays being accustomed to use these two words as synonyms of “‘profitable’’. The economic entomologist usually divides the insect world into two broad categories, beneficial and injurious. The first includes such species as the honey bee and the silkworm, which produce directly materials of commercial value; the various pollinating insects; and parasites and pre- dators. All these forms are protected and encouraged as much as possible. In this group also we should probably include the great bulk of insects that occur without particularly attracting notice one way or another but that are nevertheless of great importance in the biological system as food for birds, fish, etc.—in one sense even the blackflies and mosquitoes might be in- cluded here! But generally it is the second group, the injurious species, with which the economic entomologist is primarily concerned, because they are the forms that are in direct competition with man for the things he considers desirable or necessary. Although his research attitude is not greatly influenced by them, the insect pathologist also uses these two groupings as a matter of convenience, and therefore he becomes in part an economic entomologist. Any pathogen affecting an insect is a potential subject for investigation, primarily to obtain information about the pathogen and the disease it causes. If the 1Contribution No. 39, Insect Pathology Research Institute, Department of Forestry, Canada. Sault Ste. Marie, Ontario. Proc. Entomol. Soc. Ont. 93 (1962) 1963 insect happens to fall in the specifically beneficial group, his interest is somewhat like that of a doctor to a patient — to learn about the disease in order to suggest a cure and return the patient to usefulness. If the insect is a pest, the pathologist is interested in the possibilities of using the pathogen to reduce the widespread dependence on chemical insecticides. It is very doubtful that the insect pathologist, no matter how pure, ever completely loses sight of the dollar sign on his work. Sometimes the sign may become very blurred and dim, and this is a good thing, because it is the only way that progress can be made. This has been demonstrated in other areas, as for example in military research. It has been stated that in the military field what scientists found by unrestricted research was often of greater military importance than the things the military officers thought they wanted (18). 3 In order to obtain a proper perspective of the subject, a review of some of the highlights of insect pathology seems to be in order. For many years there prevailed a very pessimistic attitude toward the possibilities of any practical application of the discipline to insect problems. A critical look at the attempts that were made shows that this pessimism was due largely or entirely to lack of preparatory fundamental research. It is impossible to say when man first became aware that insects suffered from diseases. The Italian poet Vida in 1527 wrote a poem on the silkworm in which he referred to the ailments afflicting the insect. Probably the first of these diseases to be studied was the muscardine shown by Bassi (3) in 1835 to be caused by a fungus. Then Maestri (15) and Cornalia (5) in 1856 found minute bodies in silkworms suffering from grasserie or juandice. Many different suggestions were made as to the origin and sig- nificance of these bodies, but it was not until 1911 that Escherich and Miyajima (10) suggested that the particles were the carriers of an unknown virus which was the real cause of the disease. During the following years a number of workers engaged in studies of these particles, and between about 1925 and 1945 the evidence was accumulated that confirmed positively that the disease was indeed a virus infection. Between about 1850 and 1865 the producton of silk in France was reduced by about 85 per cent due to the occurrence of an epizootic of pe- brine, of which the cause was completely unknown although the disease had probably been enzootic since very early times. In 1865 Pasteur was commissioned by the French government to undertake a study of silkworm diseases (see Steinhaus (20) pp. 592 et. seq., for an historical account). Several workers had already shown that the occurrence of pebrine was accompanied by the appearance of corpuscles in the bodies of diseased larvae, and these were interpreted in various ways, but it remained for Pasteur to show that they actually were a parasitic organism responsible for the disease. He thought they belonged to a group then known as “osorosperms’’, and it was only in 1882 that Balbianni (1) classified them as Microsporidia in the class Sporozoa. Pasteur also separated the dysenteries or flacherie of silkworm from the other diseases. He showed that they were characterized by the rapid multiplication of bacteria in the digestive tract. Two species of bacteria were particularly important, and they are now known as Streptococcus bombycis and Bacillus bombycis. Paillot (17) has stated that these bacteria are secondary invaders, and that the true cause is an ultravirus. Depending on which bacterium is present following the virus infection, the disease is either “‘gattine” or “‘true flacherie’’. Considering the great economic importance of the silkworm a century ago, it is not surprising that the early studies of the causative organisms of insect diseases were associated with it. Indeed it is a wonder that the potential of these organisms as a means of combatting injurious insects was not recognized much earlier than it was. The first recognition of the possibilities appears to have been in Russia. Metchnikoff (16) in 1878 was able to infect beetle larvae with the fungus Hntomophthora (now Metarrhizium) anisopliae, and in 1884 Krassilstschik (13) established a special laboratory for producing the spores of the fungus on a large scale. Various other fungi were used by different investigators in succeeding years, but no one was able to report unqualified success. Even as late as 1928, it was concluded that entomogenous fungi require special conditions for their development, and that the hope of success lies in finding a very virulent fungus for each particular insect (9). The Russians also appear to have been the first to attempt to use bacteria in controlling insects. Krassilstschik (14) in 1893 isolated two species that caused disease in Melolontha vulgaris, but he could obtain in- fection only by injection into the hemolymph, and the bacteria lost their virulence in artifical culture. This was followed in 1912 by the reported success of d’Herelle (6) using Ceccobacillus acridiorum against locusts in Argentina. However, no one has been able to duplicate d’Herelle’s results. None of the early attempts to use pathogens was very successful. In fact, the first that in my opinion can be said to have produced satisfactory results was Dustan’s (7, 8) work in the Annapolis Valley about 1920. He used the fungus H’xtomophthora sphaerosperma against the European apple sucker, Psyllia malt Schmidb., and Entomophthora erupta against the green applebug Lygus communis var. novascotiensis Knight. These fungi are generally credited with having held their host insects to relatively harmless levels over many years until the balance was upset by the intro- duction of some of the newer pesticides (12). The first major attempt to develop insect pathology on a large scale as a part of biological control was that organized by the International Live Stock Exposition in 1927 to control the European corn borer. This was a truly international effort, involving Canada, the United States, Russia and eight countries of Europe. The annual reports (9) of these investi- gations gave glowing accounts of the success obtained in small experiments, but there is no record that the pathogens studied ever became of any par- ticular significance in the control of the insect although they undoubtedly play a part and at times may cause important reductions in population. As a result of these investigations, and many others that have not been specifically mentioned, together with observations of the occurrence of disease in insect populations, the general concensus was that pathogens of various kinds could, and at times did, cause tremendous reductions in insect outbreaks. But it was thought that the development of disease de- pended almost entirely on physical conditions; if the conditions were favourable, the disease would develop more or less spontaneously, while if conditions were not satisfactory no manipulation of infection would cause any significant improvement in results. This idea contained just enough truth that for many years there were few attempts to utilize or even to study seriously the diseases affecting insects, although observations of their effectiveness continued to be recorded from time to time. I recall working with an outbreak of Neodiprion lecontei on young red pine in the mid-thirties. As an adjunct to a control operation using lead arsenate, I was attempting to gather data 9 relating to the biology, and particularly the parasites, of the sawfly. Al- though mortality did not show up in the plantations, my rearings were repeatedly wiped out by what I now know was a very effective virus disease. Had I recognized it at the time, and tried to spread it around, it is quite possible that N. lecontez instead of Diprion hercyniae might now be quoted as the classic example of effective control of an injurious insect by a virus. In justification it can only be said that at that time very few entomologists thought of viruses as a means of controlling insects — or even as a cause of disease in them. The two were usually thought of in terms of the insect as a vector of plant viruses. It was not until the collapse of the European spruce sawfly outbreak in Gaspé and New Brunswick some years later, and the analysis of the reasons for that collapse by Balch and Bird (2), that the potential importance of the insect viruses was recognized and accepted. I hope that senior entomologists to-day, especially those responsible for instruction of the rising generation, are not conditioning their pupils in the same way. But it must be made abundantly clear that entomologists have not been the only culprits in this regard, as witness the recent an- nouncement of the discovery of a way to make xenon tetrafluoride after decades of teaching in chemistry classes that xenon is an inert gas incapable of reacting with other elements. Abandonment of the usual instruction by dictum, and encouragement of students to investigate anything suggested by a lively imagination, can yield great dividends. Perhaps again one may refer to the story of Pasteur, a chemist by training and profession who did not even know what a silkworm looked like when he undertook the study of the diseases affecting them. Nevertheless out of these investigations, which literally saved the silk industry from destruction, came the modern disci- pline of bacteriology, and indeed perhaps of microbiology in the broadest sense of the term. And this at a time when those who were dependent on the silk industry for a livelihood could suggest as a cure for their troubles nothing more imaginative than a reduction in taxes and a government hand-out in the form of a better strain of eggs — human nature then was very much as it is now! Although it must be said that some among the silk producers also suggested a study — still by the government — of the pathology of the disease and the possibility of controlling it by hygienic measures. Reading the literature on insect pathology in the light of present-day knowledge, one is forced to the conclusion that the chief reason the use of pathogens was not successful in early tests, and therefore did not become widespread, was that not sufficient basic information had been gathered. Consequently either the wrong organism was used — we now know that many of the pathogens are very specific in their host relations — or it was used under the wrong conditions. d’Herelle’s reportedly successful use of a bacterium to control grasshoppers is a case in point. Many investigators attempted to duplicate his work without success. It now appears that most of these people probably were not even using the same organism, it ap- parently having been lost through contamination of the cultures. Moreover, in many cases the tests were against different grasshoppers, some not even in the same genus as those d’Herelle worked with, and it now appears that d’Herelle’s organism may have been quite host specific (4). No wonder, then, that his results could not be repeated. Some time spent on a careful identification of the organism and testing for its host range would have saved a great deal of effort that was not only wasted itself but actually harmful in that it created a pessimistic attitude about the potential of insect pathology. 10 Coming closer to home, the work with the European spruce sawfly polyhedrosis undoubtedly provided the stimulus to organize a program of studies of insect pathology in Canada. The next major forest insect outbreak was the spruce budworm. It was assumed that here was another case where a virus could do a wonderful job. As everyone knows, we have not yet succeeded in controlling this insect by artificial distribution of pathogens. Again, there was in the beginning too much tendency to assume that know- ledge gained about one disease affecting one insect could be applied directly to another disease affecting a very different insect. Fortunately, those in authority at the time decided that, instead of discontinuing the project, an attempt should be made to find out why results similar to those in the sawfly epizootic were not obtained and what fundamental differences were involved; and so modern Canadian insect pathology was born. These prob- lems have not yet been solved, but we are making some progress and hope to have the answers eventually. In the meantime, success has been attained in the introduction of the polyhedrosis of Neodiprion sertifer, not known previously in North America, and in the transfer of the D. hercyniae polyhedrosis to a new population developing in the Thessalon area just east of Sault Ste. Marie and at that time the most westerly recorded occurrence of the insect in Canada. This latter introduction is now being followed to study the effects of disease at first unaccompanied by parasites, in comparison with the New Brunswick situation where parasites were already well established before the disease occurred. The program at the Insect Pathology Research Institute is divided among the disciplines of bacteriology, mycology, and virology, because it is realized that at the level at which we are working it is essential to specialize, and one individual cannot expect to do efficient work by including too broad a field. Until two years ago we also had a proto- zoologist, but since his death we have been unable to find anyone to work in this group. We also have projects in biochemistry, serology, and tissue culture. In these cases the specialists apply their skills to the solution of problems irrespective of whether the organism involved is virus, bacterium or fungus. Thus we have a fairly complete coverage of all aspects of insect pathology, and a flexibility that allows the program to be adjusted as may be required. Although we are in the Department of Forestry, it has been explicitiy stated that we are not obliged to confine our investigations to diseases of forest insects. Our main interest is the pathogen and how it affects the insect, no matter what the insect feeds on. Therefore, as circum- stances dictate, we use such insects as grasshcppers, cabbage worm, wax moth, and silkworms of various kinds, as well as those that attack trees. No control operations as such are undertaken directly. Our primary responsibility in this connection has been discharged when we are able to demonstrate that a pathogen can be used on a practical basis in control. We cooperate as required in any operation involving pathogens, and give such assistance and advice as we can. But responsibility for a control pro- gram lies with the regional organization. Again the N. sertifer virus may be used as an example. After three or four years of testing it was shown that virus could be used in the control of this sawfly at any level of opera- tion from a small hand sprayer to an application by aircraft. The virus is being used every year, and we cooperate by preparing a standardized concentrate from dead insects that are collected under the direction of the Ontario Department of Lands and Forests and shipped to us. We return the concentrate to the Department, and they distribute it as required. It 1] ‘is expected that a similar type of cooperative program will be followed if and when other usable pathogens are discovered. With this background, we can now turn to the task of trying to answer the question posed by the title. If pathogens are to be of any great useful- ness to the economic entomologist, it must be possible to apply them as and when needed in order to initiate an epizootic. Not much is to be gained by waiting until the disease appears naturally and then trying to enhance its effect. To be of maximum value it must be possible to initiate an epizootic before it would normally occur, and in many cases under conditions in which it would not occur at all. Before such a result can be expected it is necessary to know the conditions under which an epizootic can develop — or perhaps even more important the conditions under which it cannot pos- sibly develop — and it is also necessary to have a supply of inoculum avail- able to initiate infection. Consider first the work in bacteriology. Some of the early este tions have already been mentioned. Various organisms, including Bacillus thuringiensis, were tested against different insects, and only inconclusive results were obtained. But now, as a result of information gathered through fundamental studies in a number cf laboratories including ours, at least three firms in the United States are engaged in commercial production of B. thuringiensis for use in insect control. It is entirely possible that the bacterium might have been used, and might even have developed to today’s level of production and use, without any of this research. But certainly it would not have developed nearly as quickly — and quite probably not as cheaply in the long run — had dependence been placed on empirical or trial- and-error methods instead of on planned investigations. It is now known, in this case, not only what insects are killed but in many cases how they are killed, and the mechanism is different in different species. Some are affected by direct germination and growth of the bac- terilum giving rise to a true septicaemia. Others are killed by the toxic action of a proteinaceous material that is produced when the Bacillus — sporulates. And still others are killed by an interaction or succession of the effects of the two components. Recently, ev:dence is accumulating that there is still another factor, a soluble exotoxin, involved where certain insects or groups of insects are concerned, and the particular method of production may have an important bearing on the amount produced and therefore on the effectiveness of the product. Moreover, it is not yet certain that the entire crystal toxin is always necessary or involved in causing mortality, nor is it known whether the toxins produced by different bacteria are the same or different. It may be that only a chemically small fragment of the crystal is the real toxin. If so, this would bring closer the possibility of synthesizing the material, or perhaps of discovering a whole new family of proteinaceous compounds with specific toxic properties, each having its particular application in insect control. As experimentation proceeds, it is evident that there is great variation in the susceptibility of insects. In several cases the reasons are now known, and it is possible that eventually we may be able to measure certain physio- logical characteristics of the insect, or perhaps even to observe its habits, and on that basis to predict whether or not the bacterium can be used with hope of success, thus greatly reducing or eliminating the need for time- consuming and ‘frequently costly field tests. No doubt every entomologist has at one time or another seen a dead fly stuck to a window and surrounded by a small halo. The fly has been killed by a fungus, Entomophthora muscae (Cohn), and the halo consists 12 of discharged condiospores. This is only one of the many different species of fungi that infect insects, sometimes quickly and effectively eliminating tremendous populations. Numerous attempts have been made to use fungi to control injurious insects, but the great majority have been failures, or at best only limited successes. The effective use of most of the fungi is dependent on our ability to obtain pure sporulating cultures on artificial media. The resting spore rather than the conidiospore is of course the stage of choice, because it is highly resistant to unfavourable conditions and therefore can be stored for long periods and still remain viable. Although a large number of fungi are very easy to grow on media, many of the pathogenic forms apparently have very specific requirements and have not been successfully cultured. Species of Entomophthora have been particularly difficult to grow. In an effort to find a suitable medium a wide range of carbohydrates, amino acids, vitamins, minerals, and other nutritive materials has been tested in num- erous combinations and under various physical conditions. It is hoped that a careful analysis of the results will yield a basic medium on which these and other normally obligate parasites will grow. A second difficulty arises after the spores have formed, namely, inducing them to germinate. The conditions causing germination are im- perfectly understood, but there seems to be little doubt that such physical factors as temperature and humidity are of great importance. It is possible that a ripening period is involved, or perhaps that as in the case of some seeds an inhibitor must be leached away. Further research will undoubtedly solve these problems. But this will have to be carefully planned and carried out, rather than depending on ad hoc tests as so often used in the past. The part played by virology in the development of insect pathology as a contribution to economic entomology has already been indicated. Here again no great progress was made until the fundamentals were examined. For instance, the polyhedrosis of the European spruce sawfly was trans- ferred from New Brunswick to various places in Newfoundland, Quebec and Ontario, but it was not known whether or not the disease was already there, and no serious attempt was made to find out just what happened afterwards. The insect has not become a serious pest in any of these areas, but whether this has been due to the virus or to other factors is not known. It was not until the fully-documented introduction into the Thessalon area, referred to earlier, that any conclusive evidence was obtained regarding the effectiveness of this virus in spreading and controlling the sawfly when introduced into a disease-free population. There is still a great deal to be learned about the interaction of disease and parasites in a population. When the habits of the insect are such that natural spread is rather slow, as for instance when the female lays her eggs in one cluster, parasites may be of very great importance in distributing infection, in addition to their direct attack. Thus the value of a disease might be assessed quite differently depending on whether or not parasites are present. Conversely, if the female lays her eggs singly, and moves about actively, this effect of parasites may be much less pronounced. It is ex- pected that the current studies in Thessalon will shed further light on this problem, since parasites have recently become fairly numerous. Early work with insect viruses led to the conclusion that they were very highly, in fact almost completely, host specific. Many attempts were made to induce cross-infection, especially with those that had been found highly virulent in their normal host, but little or no success was achieved. Recently, however, at least one or two viruses have been transmitted to 13 different hosts, and it is now important to know the mechanism involved, and whether it is something that can be caused to occur at will. It is also important to know whether or not such a transfer is apt to occur naturally, because it might conceivably be a serious threat.to beneficial insects. The virus that at the moment seems most adaptable is TIV, the Tipula irides- cent virus, which can infect a dozen or more different species from at least three or four different orders (19). It is being examined very carefully using electron microscopy to follow its development, in an effort to deter- mine what parts of the cell are affected and what is peculiar to either the eell or the virus, or both, that accounts for this host range. A part of the biochemical program is following along the same lines. It is too early yet to say that specific practical applications will be de- veloped, but the possibilities are promising. The significance of the nucleic acids — the “thread of life” of the science reporters — is now accepted by all biologists. The insect pathogens also have nucleic acids, and in the viruses we now know that these differ according to the type of virus, i.e. the cytoplasmic versus the nuclear, the polyhydroses compared with the granuloses or the naked types, and so on. The significance of these dif- ferences is being investigated and the explanation when it comes will undoubtedly help to rationalize future use of viruses in insect control. Serological studies likewise are aiding our understanding of what goes on when insects become infected with pathogens, as well as increasing our knowledge of the pathogens — and of the insects — themselves. It is quite possible that from these studies will come an explanation of the degree of host specificity in a particular virus. Already evidence is accumulating that may help to explain why some insects are affected by crystal toxins of bacteria while others are not. And as a side benefit, some of these sero- logical studies may be adapted to assist taxonomists in arriving at a better understanding of the systematic relationships between insects. The growing of animal tissues in artificial media has long been a tool for studies in medicine and vertebrate physiology. It should be equally valuable in insect pathology and physiclogy. Several attempts have been made to develop a technique for growing insect tissues in culture, but until quite recently little success has been reported. It is now possible to maintain isolated insect tissues in the living state for fairly extended periods, and just recently Grace (11) reported that he has been able to maintain cells actively growing through as many as 29 sub-cultures. We are interested in the potentialities of this technique for at least one very practical reason. All our knowledge of the development of a pathogen in the body cells of an insect is based on observations made at specified times after the infective agent has been appropriately introduced into the insect body. We assume that the differences observed in cells at, for instance, 12 and 24 hours after infection actually represent a difference of 12 hours in development. But this is not necessarily so, because there is no way of knowing the time at which an individual cell was invaded. Development of a technique for growing cells in culture will make it possible to follow the infection process in individual cells, and before long we hope to be able to work with such cells of known age and antecedents, and from them to work back to the generalized system with much more certainty than we have to-day. And finally there are studies in insect physiology. We are concerned with these as they serve to explain the action of the pathogens — actually it is difficult to draw a line between physiology and biochemistry. One example will illustrate the practical importance of such investigations, 14 that is, the relationship between the pH of the insect gut and the toxicity of the bacterial crystal. Until this had been established there was no ex- planation of the fact that one insect species was easily killed by the toxin while another was unaffected. Consequently various investigators reported very different results when tests were based on different insects. It is now known that certain insects are completely unaffected by the toxin, and a simple test of the gut pH, while it will not show with certainty that an insect can be killed, will indicate those that probably cannot. Thus a great deal of trial and error testing may be avoided. “Tt can no longer be stated that ‘‘necessity is the mother of invention”’ but it may be truly said that steady, methodical investigation of natural phenomena is the father of industrial progress.” Leave out the word “ dustrial’ and this statement made by John Brunner in his presidential address to the Society of Chemical Industry in 1889 applies to the field of applied entomology to-day.° I hope the outline of insect pathology presented here will convince at least one or two skeptics that fundamental research really can be of some practical use. In conclusion, for those yet unconvinced, and bearing in mind the relative youth of insect pathology as a branch of entomology, I can only repeat the remark attributed, I believe, to Faraday when he was asked what possible value there could be in electricity : “Of what use is a new-born baby ?” References BALBANNI, E. G. (1882). Sur les microsporidies ou psorospermies des Articules. Compt. Rend. Acad. Sci., Paris, 95: 1168-1171. (cited in Steinhaus, 1949). BALcH, R. E. and Birp, F. T. (1944). A disease of the European spruce sawfly, Gilpinia ‘hercyniae (Htg.), and its place in natural control. Sci. Agr. 25: 65-80. BassI, A. (1835). Del mal del segno calcinaccio 0 moscardino malattia che afflige i bacchi da seta. Parte 1. Teorica Tip. Orcesi, Lodi (cited in Steinhaus, 1949). BucHER, G. E. (1959). The bacterium Coccobacillus acridiorum d’Herelle : Its taxonomic position and status as a pathogen of locusts and grasshoppers. J. Insect Pathol. 1: 331-346. CORNALIA, E. (1856). Monografia del bombice del gelso. Mem. R. Istit. Lombardo Sci. Lett. Arte, 6: 3-387. (cited in Steinhaus, 1949). d’HERELLE, F. (1912). Sur la propagation, dans la République Argentine, de |’4pizootie des sauterelles du Mexique. Compt. Rend. Acad. Sci., Paris, 154: 623-625. DusTAN, A. G. (1923). The control of the European apple sucker by means of parasitic fungus. Fruit Growers’ Ass’n. of Nova Scotia, 59th Ann. Rept., 100-104. DusTAN, A. G. (1924). The natural control of the green apple bug (Lygus communis var. novascotiensis Knight) by a new species of Empusa. Que. Soc. Prot. Plants, Ann. Rept. 1922-1923: 3-8. ELLINGER, TAGE (editor). (1928-1931). International Corn Borer Investigations, Scien- tific Reports, vols. I-!V. International Live Stock Exposition. Union Stock Yards. Chicago. ESCHERICH, K. and MiyaAgIMa, M. (1911). rece uber die Wipfelkrankheit der Nonne. Naturw. z. Forst.-u. Landw. 9: 381-402 GRACE, T. D. C. (1962). Establishment of four strains of cells from insect tissues grown in vitro Nature 195: 788-789. JAQUES, R. P. and PATTERSON, N. A. (1962). Control of the apple sucker, Psyllia malia Schmidb., by the fungus Entomophthora sphaerosperma (Fresenius). Canad. Ent. 94: 818-825. KRASSILSTSCHIK, I. M. (1888). La production industrielle des parasites végétaux pour la destruction des insectes nuisibles. Bul. Sci. France 19: 461-472. (cited in Steinhaus, 1949). a ey I. M. (1893). Sur la graphitose et la septicémie chez les insectes. Mem. Soc. Zool. de France 6: 245-285. “Quoted by Ritchie Calder in ‘‘Speculative Research’’, Discovery, October, 1960, pp. 420-425. 15 Maegstri, A. (1856). Frammenti anatomici fisiologici e patologici sul baco da seta. Fusi, Pavia. 172 pp. (cited in Steinhaus, 1949). METCHNIKOFfF, E. (1879). Zeitschrift der Kaiserlichen Landwirtschafts Gesellschaft fir Neurussland, Odessa. (Quoted by Wallengren and Johanson, Internat. Corn. Borer Invest:, Sci. Rept. 2; 131, 1929). ; PaiLuot, A. (1930). Influence des infections microbiennes secondaires sur le dével- oppement des ultravirus chez le Bombyx du murier. Compt. Rend. Soc. Biol. 104: 585-586. PrIcE, Don K. (1962). The scientific establishment. Science 136: 1099-1106. SMITH, KENNETH M. and Rivers, C. F. (1959). Cross-inoculation studies with Tipula iridescent virus. Virology 9: 140-141. STEINHAUS, E. A. (1949). Principles of Insect Pathology. McGraw-Hill Book Co. Ine. New York. (Accepted for Publication: January 16, 1963) ij How Useful is the Basic Research Program to Economic Entomology Ill. ENTOMOLOGY RESEARCH INSTITUTE, OTTAWA W. R. M. MASON Entomology Research Institute, Canada Department of Agriculture, Ottawa, Ontario Definitions The usual initial reaction upon being asked to expound on a subject such as this is to seek definitions. In this case one naturally is led to define basic and economic research as applied to entomology. Both these terms have rather broad meaning which we all understand fairly well. Every person has a slightly different personal concept; in fact there is an infinite number of differences of opinions about the fringes, but there is broad agreement on the general core of meaning of these terms. Webster’s dic- tionary is an excellent starting place for definitions. It states that basic research seeks ic understand the causes of natural phenomena whereas ecoromic entomology is the adaptation of available entomological and re- lated information to specific gainful purposes. For this discussion I in- terpret the term ‘economic’ entomology broadly, to include medical en- tomology and applied forest entomology as well as the conventional agricul- tural, household and stored products entomology. I also include insect identification service in this category because it is merely a case of specialist consultation on an economic entomology project. A function which looms large in the work of the Entomology Research Institute is taxonomic revisionary work. This type of work does not appear to fit into either basic or economic research very comfortably or only in a fractional way. It is in fact observation, collection, and organization of facts into a useful reference material. Really a third category is needed to include this type of research. Dr. Robert Glen, Canada Department of Agriculture, has given this subject long and serious thought and has published an excellent discussion of research types (Glen, 1958). To suminarize, Dr. Glen has divided kinds of research in two different di- mensions. The first dimension depends upon the reason that the research is carried out. Research which is an end in itself he calls pwre or academic — and that research which is a means to an end he calls economic or applied. In the former type of research, since the goal is either unknown or does not Proc. Entomol. Soc. Ont. 93 (1962) 1963 16 matter, the man doing the research is supported: in the latter the goal is well known and a succession of men may take up the research at different times. Here, therefore, the project is the thing supported while entomolo- gists come and go. The second dimension used by Dr. Glen is that of the kind of research done, regardless of the reason for doing it. Here he makes the breakdown into three categories: basic research which seeks to understand the causes, background research which consists of observation, collection, and organi- zation of facts into useful reference material, and developmental research which is the adaptation of information to specific purposes. Almost all government research is applied whether at the basic, background, or development level and only a small fraction (less than 5%) is pure basic research. When these divisions are applied to research in insect systematics, the only field in which I feel well qualified to comment, one finds that in- vestigations into population dynamics, evolutionary mechanisms, and zoogeographical principles can be classed as basic research; the discovery of geographical distribution, identification characters, life histories, habits, hosts and taxonomic revisions of groups, in other words typical museum morphotaxonomy, is background research; and the writing of keys, develop- ment of rearing techniques, and some of the more difficult types of identi- fications are developmental research. It is common knowledge, of course, that all these categories intergrade extensively. The same published paper may contain several “types” of research and the same man may do two or three kinds simultaneously. There is also a constant evolution of projects from one type of research to another. | Dr. Glen lays stress on the idea that no one kind of research is better than any other kind — in fact good and poor research are measured only by the way in which they are carried out and not by the category into which they fall. The type of research is governed, not by the ability of the research worker, but rather by his personality or the needs of the times and of the particular job. The Needs for Research ~ To return to the original question of this paper, that is “how useful’, we should consider why the different types of research are needed. The need for developmental, or as one might also put it, empirical, research is usually urgent: it is a matter of dollars and cents per minute. At other times it may be an alleviation of human or animal suffering or merely an improvement in comfort. Whatever the reason, the results are wanted immediately and the empirical researcher must use whatever accumulated background information he can discover to develop the most likely control. In the absence of sufficient background information he must fall back on the old watchword of empirical research “try it and see’. Although the need for applied research is obvious to everyone the need for background research is not so well known except to those who them- selves are engaged in research. Anyone who has ever conducted a literature search knows the need for organization of the countless fragments of know- ledge which have been accumulated in scientific journals. This vast pool is completely unusable without organization and synthesis. Catalogues of all types are essential, not only to the applied research worker, but also to the basic worker. One of the greatest worries of those engaged in scientific research nowadays is the rate at which these disorganized fragments of knowledge are outgrowing our ability to organize and catalogue them. This middle ground of research is not nearly so glamorous as basic research nor 17 so strikingly needed as economic research but, lamentably, it is not nearly so well supported. The amount of attention that background research now gets is well illustrated by the title of this symposium. A great increase in the stress upon background research is needed to save research workers from wasting their time by unknowingly duplicating one another’s efforts. I believe the need will increasingly force administrators and granting organizations to see clearly the steadily growing urgency. The need for basic research is obvious, but nevertheless basic research is that type of research most often and most eloquently defended. I need only to say that basic research is essential for any real progress beyond the stage of refinement and polishing of existing techniques. It is essentially exploratory and therefore must be expected often to yield immediately unusable results. Eventually the results will prove to be of use: no one knows where, or when. The supreme practical goal of basic research is the great “breakthrough” discovery. One of the best illustrations I know is the discovery of the medical use of penicillin. For generations of bacteriolo- gists, penicillin existed merely as a well known nuisance phenomenon. When the agar plate of the bacteriologist was contaminated with mold the growth of the bacterial culture was inhibited and the experiment spoiled. Finally came the breakthrough — the flash of genius: “If a mold will inhibit the growth of a bacterial culture on an agar plate maybe it will do the same thing in the body.” The rest of the story of modern development of anti- biotics is just one of hard work, persistence and refinement. A writer, whose name unhappily I have forgotten, left me with the statement that probably only five minutes of real thought has ever occurred in the history of the human race. When one considers the number of microseconds oc- cupied by each flash of genius the statement becomes amazingly believable. The Choice of Research One of the greatest. practical reasons for the choice of carrying out either basic. or economic research by an individual, lies in the personality differences between research workers. Some prefer short-term experiments yielding quick results. They like to feel that they are being of service to their fellow men and enjoy seeing the results of their labors benefit those around them. These men tend to congregate into economic research and are prob- ably happiest there. Others prefer long-range experiments and care little about quick results. Often they are not as much interested in their fellow _ men but are, instead, fascinated by the things about them. These men tend to congregate into basic research. Neither type of research worker should be forced into the other mold. Often good men can be lost to an organization which forces all its men to do exclusively, or almost exclusively, applied work. Probably the converse is equally true but I have not heard of any instances: the tendency seems to be overwhelmingly in the direction of applied work. There seems to be a widespread tendency to look upon basic research as “prestige” work and most research workers like to do at least a small amount of this basic research. There is a natural development in almost any project, however empirically it may start, for the researchers to start asking “why”. This leads eventually into a desire to do basic research. Usually the senior man on the project is the one who, because he has been longest engaged with the problem, first gets this desire, and because of his seniority is allowed to indulge it. Thus the young entomologist often sees the senior men doing basic research while the junior men carry on the applied program. Perhaps this gives rise to the prestige feeling in connection with 18 basic research. Perhaps, also, the student, who during the summer has to wield that symbolic tool of the applied entomologist, the insecticide spray gun, and who, during the winter sees his professor working on a basic academic project, feels that basic research is the goal to be striven for. Whether it is justified or logical or reasonable or not, the attitude undeni- ably exists and a research organization can discourage basic research only at the peril of losing its more ambitious and dedicated workers. An organi- zation can also be stultified by ignoring basic research. As an example of this in the field of insect taxonomy please read the editorial by the com- mittee on insect surveys and losses (Bul. Ent. Soc. America 8: 105. 1962). The Entomology Research Institute I have been asked to apply the question asked in the title to my own organization, The Entomology Research Institute. There are five sections within the Institute: 1. Taxonomy; 2. Physiology, Ecology and Genetics; 3. Crop. Insects; 4. Nematology; 5. Apiculture. The last two sections do not seem to need to be discussed since one deals with nematodes which are not insects and the other with honey bees which are essentially livestock. The Taxonomy section has a staff of 21 research officers, ‘the great bulk of whose publishable work is background research. They spend approxi- mately one-third or more cf their time on applied research, or in other words, identifications of insects for economic entomologists. The other half or two-thirds of their time is divided approximately equally between re- search and non-research duties. Only a small amount of time, perhaps 5% is allotted to basic research and this is spread among a number of research officers. The second section contains the remnants of several units of the former Division of Entomology. Four of the officers are medical entomolo- gists or ecologists with a medical entomology background; three are physi- ologists and two are geneticists. The work cf the medical entomologists is rather equally divided between all three fields of research; that of the physiologists concerns mainly insect blood and saliva and is basic but in a decidedly economic framework ; that of the geneticists is largely basic. The Crop Insects section comprises three officers whose work is largely at the applied level but has been becoming somewhat more basically inclined in recent years. If one should ask, Tey is any of the work in this Institute useful 6 me in my economic fields‘ ?’ T can only answer, “Wait and see.” Today’s economic research lives on the basic research results of yesterday. Today’s. basic research may benefit some economic research in the future but just which projects will be helped is not sure, although forsighted planning and fortunate choice of personnel can greatly reduce the uncertainty. The basic research program in this Institute may be compared to an investment pro- gram. Some investments show only a loss, others make slow but steady gains, and a few are spectacular successes. If the initial investments in either stocks or research are well chosen the entire program will yield pro- fitable results but one cannot predict the unknown element of luck that is inevitably involved. If the question asked in this symposium does nothing else, it will undoubtedly accomplish a good purpose in making people think about the relationships of basic and economic research and in allowing those in either field to hear something of the thoughts of workers engaged in different applications of entomology. I hope that it will remind the basic research entomologist of the basic reasons for the existence of his job and that it 19 will remind the economic entomologist of his basic dependence upon funda- ment l research. References | GLEN, R. (1958). Elements of Entomology—the Program. Bul. Ent. Soc. America 4: 46-49. (Accepted for Publication: January 16, 1963) O Moderator’s Comments’ on the Symposium, How Useful is the Basic Research Program to Economic Entomology A. S. WEST® The four contributors to this symposium did an excellent job. The papers make interesting and thought-provoking reading. The discussion at the conclusion of the formal presentations indicated that the topic had not only aroused interest and led to the display of some differences of opinion, but also furnished a point of departure for a wider discussion. The combination of Dr. Beirne’s specific review of the work of an Institute, Dr. Cameron’s historical approach, Dr. Mason’s philosophical approach and Dr. Chefurka’s challenging departure provided meat for everyone as was evident from the spirited discussion period. No attempt has been made to record the entire proceedings of the question period. The comments which follow are intended to indicate the trend and scope of the questions raised. These questions called on contribu- tors to back up statements with specific information, to provide answers to questions not arising directly from statements made, and in general ranged far wider than the scope of the seminar topic. Largely as the result of Dr. Chefurka’s presentation a number of questions and comments related to the role of the Universities. Dr. Monro pointed out that there had been no real debate on the subject as titled and that pure research has been shown to be of real value. There appeared to be general agreement that the staffs of research Insti- tutes are “economy minded’. Rather than a clear-cut distinction existing between the economic entomologist and the basic researcher, it was sug- gested that these are becoming one. This view was accepted with reservation by some. Dr. Monro also suggested that the debate showed the existence of some uneasiness over some aspects of the subject, and that this is good since it may indicate greater attention to how to divide our resources and or- ganize our effort. The need for keeping a proper balance of field and laboratory studies and for the fostering of a mutual respect between the basic and the economic researcher (if these are distinct) was recognized. The “prestige” value of basic research came in for considerable dis- cussion and there was no unanimity of opinion. An example of a contributor being asked to back up a statement was Dr. Monro’s request for Dr. Beirne to list the 13 species of insect pests which have been controlled by biological means. Dr. Beirne called on Dr. Turnbull who listed: the larch sawfly, the holly leaf-miner, the European 'The moderator is very much indebted to Dr. Belton for his assistance in recording the discussion. © *Queen’s University, Kingston, Ontario. Proc. Entomol. Soc. Ont. 93 (1962) 1963 20 AG # Se Ts a Ee ae ee etter ate nye oi oo Sk ree | Select bibliographies of early papers were given by Slingerland (1898) and Simpson (1908). Citations of Vineland Station staff members followed by “(unpubl.)”’ refer to unpublished data in the Annual Reports of this Laboratory. Injury and Economic Importance _ The codling moth larva is the “apple worm” familiar to an older gen- eration but perhaps not to younger people whose only contact with apples is with graded fruit from supermarkets. The tunnels of the larvae through the fruit leave them quite unfit for any purpose (Fig. 3). Larvae killed by insecticides or dying from natural causes while penetrating the epidermis cause superficial scars or “stings”, which may not seriously affect the edibility of the fruit but which cannot be tolerated under modern grading regulations. The codling moth is the most destructive insect pest of apples in On- tario, aS in most other parts of the world. Apples cannot be grown com- mercially in the Province without extensive insecticide application for its control. Unsprayed trees in Southern Ontario regularly lose 75 to 95 per cent of their crop from its attack. The cost of insecticide application against the moth is a considerable part of the total costs of apple production. Also, much of the expense of controlling the European red mite, Panonychus ulmi (Koch), and other tetranychids and possibly the red-banded leaf roller, Argyrotaenia velutinana (Walk.), is attributable to the side-effects of DDT and other insecticides used against the codling moth. History and Distribution From its original home probably in southeastern Europe the codling mcth has followed the spread of apple culture practically throughout the temperate regions of the world except eastern Asia (Anon., 1951). Slinger- land (1898) related its early history in Kurope and North America and stated that it was probably introduced to New England about 1750. Beau- liei (1937) also treated its early history. The first published record from Canada was by Bethune (1871) who said it was destructive throughout Ontario in 1868. In 1906 Brodie (Anon., 1907), recalling from memory, said it first appeared in the Province about 1858-1860, which seems too late in view of Bethune’s remarks. Fletcher (1886) said it occurred - throughout the Maritime Provinces in 1885. Mr. H. T. Stultz of the Re- search Station, C.D.A., Kentville, N.S., (n litt.) believes it may have been introduced into Nova Scotia from France at a very early date, for apples were growing in the Province by 1635, if not earlier. Its introduction to Quebec also long antedated any published record; it was abundant by 1885 (Fletcher, 1886). Soon after the first discovery of the moth in British Columbia in 1905 near Victoria, it appeared in the interior of the Province and by 1916 it menaced the main apple-growing districts of the Okanagan. Vigorous efforts by the Provincial Government limited its spread and eradicated some localized infestations, but repeated introductions made the task hopeless and in 1925 attempts at eradication were abandoned (Treherne, 1919; Hoy, 1942; Dr. James Marshall, in litt.). According to Mr. H. P. Richardson of the Research Station, C.D.A., Winnipeg, (in litt.) the codling moth has never occurred in Manitoba. As hardy Malus varieties have been grown in the Province for many years the absence of an insect as easily transported as the codling moth is likely due to lower winter temperatures. 23 mn Hosts The adler moth attacks the fruits of apple, pear, quince, apricot, peach, plum, and cherry, from all of which it has been reared in Ontario. As elsewhere, it is most destructive to apple and scarcely less so, though more easily controlled, on pear. It is unimportant on stone fruits in Ontario, as in most other areas, but is destructive to apricots in California (Madsen and Borden, 1954) and South Africa (Pettey, 1925). It is a major pest of walnut, Juglans regia L., in California (Quayle, 1926) and also attacks this host in Europe. It has been reported on such incidental hosts as chestnut _ (Castanea sp.), persimmon, and orange but the authenticity of some of these records is uncertain. In Colombia the moth is commoner on a wild host, Rheedia madruna Planch and Triana (Family Guttiferae) than on apple (Garcés and Gallego, 1947). The writer has noticed heavy infesta- 3 tions on some varieties of ornamental crabs at Vineland Station. Bieberdorf (1956) mentioned haws (Crataegus spp.) as less desirable hosts of the codling moth but neither Wellhouse (1920) in New York nor the present author in Ontario recovered the moth from large quantities of hawthorn fruits. It is well known that the severity of codling moth attack differs among varieties of apple but none appears to be resistant enough to escape serious injury when the general level of infestation is high. Hall (1929) reported that Jonathon was the least susceptible of nine varieties observed and Cutright and Morrison (1935) also found this variety to be relatively resistant. Putman (1949) found that an epidermal grease present on Jonathon apples after storage was toxic to newly hatched larvae but it is not known whether this observation is pertinent to resistance in the orchard. Taxonomy and Descriptions of Stages Heinrich (1926) restricted the genus Carpocapsa Treitschke, 1930, of the family Tortricidae to the single species pomonella (L.), 1758, though — earlier taxonomists included other species. Carpocapsa is closely related to Laspeyresia Hubner, 1826, and Grapholitha Treitschke, 1929, which contain such well-known species as the pea moth, L. nigricana (Steph. ), the oriental fruit moth, G. molesta (Busck), and the lesser appleworm, G. prunivora (Walsh). Species of all three genera are placed in Cydia Hubner by British and some other European writers. Still other modern European writers put pomonella in Laspeyresia, Enarmonia Hibner, 1826, or Argyroploce — Hubner, 1926. The specific synonym pomonana Treitschke, 1830, was used until very recently by some European authors. “La pyrale de la pomme?”’ is the official common name in Quebec Province (Anon., 1947), though “le carpocapse des pommes”’ is most fre- quently used in France. The adult (Fig. 1) has a wing span of 15 to 20 mm. The forewings are gray with fine transverse striations and with a large brown distal patch with two metallic bronze bars. The hindwings are brown. Forbes (1923) gave a technical description of the moth and Heinrich (1926) — figured the male and female genitalia. Busck (1908) described simpsoni as a variety, a form of C. pomonella with colour pale buff. It appears to occur most frequently in the western United States. Some five or six specimens of this or a very similar form were reared at Vineland Station in several hundred thousand normal moths. As Rice (1941) found that the characters of this variety were inherited as a unifactorial recessive it might be useful as a genetic marker in attempts at artificially induced male sterility. 24 ae The ege (Fig. 2) is broadly ovate, thinly lenticular and closely ap- pressed to the substrate; it measures about 0.98 by 1.25 mm. The chorion is very finely reticulate. The egg is at first colourless and translucent; when incubation is about one-third complete a transient red ring appears about the embryo and the black head capsule becomes visible one or two days before hatching. : The early instars of the larva are whitish with head capsules black. There are usually five instars (Hammer, 1912) but if the larvae are poorly nourished there may be as many as eight (Jenne, 1909). The mature larva (Fig. 3) is about 20 mm. long, creamy white tinged with pink above and with head capsule brown and the cervical shield paler brown. In male larvae the dark testes are visible through the dorsal integument (Jones and Davidson, 1913). Peterson (1948) and MacKay (1959) gave technical de- scriptions of the larva. It can be distinguished from the other two apple- infesting caterpillars common in Ontario, the oriental fruit moth and the lesser appleworm, by its larger size when mature and by the absence of an anal fork or comb above the anus. Life-History The terminology used here for the various stages in the life-history is that followed for many years in North America. A brood includes all individuals in a particular stage, e.g., egg, larva, etc., in any one generation. Each brood is numbered according to the generation to which it belongs. The brood of moths from overwintered larvae, really part of the final one or two generations of the previous year, is termed the spring brood. These moths produce the first brocd of eggs, which together with the first broods of larvae, pupae, and adults constitute the first generation. The first brood of moths is therefore actually the second to appear during the season. Later broods and generations, when they occur, are numbered accordingly. The number of generations per year varies with climate. At its nor- thern limits the moth is nearly or quite univoltine; in southern Ontario there are two generations; in Virginia, three (Schoene et al., 1928) ; and in Georgia, four or sometimes five (Van Leeuwen, 1929). The last generation in any locality is only partial; some larvae of one, sometimes two, pre- ceding generations also enter diapause and overwinter. In Colombia the codling moth is said to breed practically throughout the year on the fruit of Rheedia madruna (Garces and Gallego, 1947). Mature larvae in diapause overwinter in cocoons on the trees (Fig. 4) and to some extent in debris on the soil surface. Hall (1929) found that at Vineland Station pupation began from April 19 to May 21 over a six-year period, the average date being April 28. Each year some larvae did not pupate until July. 7 The earliest moths of the spring brood emerged from May 20 to June 14 in different years, usually about two days after full bloom of apples, and continued for nearly two months until late July or early August. The preoviposition period averaged 3.7 days and oviposition continued for an average of 5.3 days. The first-brood larvae began to hatch about June 25, about a week after the calyces closed on the fruit, and hatched in greatest numbers about July 21. The latest hatched on the average on August 10, but in some years as late as August 30. Mature first brood larvae left the fruit a minimum of 12 days after hatching; those hatching late in the season had greatly extended feeding periods of up to 73 days. Some first- brood larvae remained in diapause until the following spring; others pu- pated an average of 6.1 days after leaving the fruit. First-brood moths 25 began to emerge as early as July 19 but usually about August 4, and often continued past the middle of September. They deposited eggs after an average pre-oviposition period of 2.6 days. The second brood of eggs hatched in 6 to 23 days. The larvae began to enter the fruit from August 3 to 27 in different years. In two of six years hatching of the second brood overlapped that of the first and the greatest separation between broods was 13 days. The larvae left the fruit after a minimum feeding period of 14 days. All mature larvae of this brood entered diapause. The proportion of first-brood larvae that pupate the same season in Ontaric varies both geographically and from year to year. Caesar (1914) stated that in colder areas such as Ottawa few or none pupate; at Guelph, Ccllingwood. and Whitby from 2 to possibly 8 per cent do so; and in the Niagara Peninsula and other warm districts a much larger percentage. Hall (1929) found that from 4.5 to 44 per cent with an average of 11.6 pupated during the six years from 1923 to 1928 at Vineland Station in the Niagara Peninsula. Garlick (1948), also at Vineland Station from 1941 to 1945 and using orchard-collected larvae, found that the percentage pupating the same season was over 80 per cent for those maturing in July; after about August 10 the percentage fell rapidly and none of those maturing after August 25 pupated. Entomologists whose experience extended back to the earlier years of the present century generally believed, on rather subjective evidence, that the proportion of larvae giving rise to a second generation had increased during the period, especially in the cooler districts such as Georgian Bay and the northeastern shore of Lake Ontario, and that this increase was one cause of the increasing difficulty of codling moth control. Although Gar- lick’s (1948) figures from collected larvae are not directly comparable with those of Hall (1929) from reared larvae they suggested that the second generations were relatively larger in 1941 to 1945 than in 1923 to 1928. Beaulieu (1940) found that 49, 26, and 18 per cent of the first-brood larvae in 1937, 19388, and 1939, respectively, pupated the same seasons in southern Quebec. LeRoux (1959) gave further evidence of a considerable second generation in the same region, in a climate similar to that of eastern Ontario where Caesar (1914) estimated the percentage of pupating larvae to be very low. Diapausing larvae have a somewhat longer feeding period than non- diapausing ones (Siegler and Simanton, 1915). The stimuli that evoke diapause will be considered later. Although the annual number of generations of the codling moth is largely fixed by environmental factors, Garlick (1938) showed that it may have a partially genetic basis. By selective breeding for three years he produced strains in which the proportions of univoltine and bivoltine in- dividuals were considerably altered from those in unselected strains. Genetic differences have also been demonstrated in the extent of multi- voltinism between moths from different geographic regions. Garlick (unpubl.) obtained hibernating larvae from Nova Scotia and reared their progeny for two years in a screened insectary at Vineland Station together with local moths. The percentages of non-diapausing first-brood larvae for the Nova Scotia and Ontario strains respectively were 6.8 and 27.8 in 1939 and 14.7 and 37.8 in 1940. Natural selection has apparently produced strains in which the time of spring emergence and the number of generations are adapted to survival on a particular host. In South Africa Pettey (1925, 1926) found that the 26 moth in apricot orchards was predominantly univoltine, whereas in pear orchards in a cooler district it was trivoltine. He tentatively concluded that nutrition of the larvae or their ancestors influenced voltinism. An alterna- tive explanation is that a genetically determined univoltine strain had been selected in the apricot orchards through elimination by starvation of later generations hatching after the fruit was harvested. In Oran, North Africa, no overwintered larvae pupated on quince trees at a time when 28.5 per cent pupated and 8.9 per cent emerged as moths on apple and pear trees (Frezal, 1938). Armstrong (1946) found that the spring-brood moths from larvae col- lected from an old, isolated pear orchard in the Niagara Peninsula emerged later than those from apple orchards in the same district. He also found that young larvae suffered very high mortality when entering immature pear fruits and believed that this mortality had gradually selected a late- emerging, one-generation strain of the moth whose larvae hatched when the fruits had begun to soften. Smith (1941) discussed the formation of a strain especially adapted to walnut. Basinger and Smith (1946) found differences between the times of spring emergence of moths from walnut and from apple and pear in some districts of California but not in others. Moths from both apple and pear emerged about the same time. Madsen (1956) suggested that a late spring flight of moths in California pear orchard arose through elimination of early-emerging moths following several years of early-season use of DDT. Fecundity Hall (1929) recorded 48 per cent males and 52 per cent females among 5,525 reared moths. The difference is significant at P<0.005. He obtained an average of 64 and a maximum of 234 eggs from spring-brood moths and an average of 83 and a maximum of 208 from first-brood moths at Vineland Station. These numbers are distinctly greater than most of those reported in various regional life-history studies in the United States (Siegler and Simanton, 1915; Quaintance and Geyer, 1917; Siegler and Plank, 1921; Glenn, 1922; Newcomer and Whitcomb, 1924; List and Yetter, 1927; Selkregg and Siegler, 1928; Van Leeuwen, 1929; Yothers and Van Leeuwen, 1931; Newton, 1935). The greatest reported number laid by one moth was 345 (Isely, 1938). A number of authors, such as List and Yetter (1927), found more than 300 oocytes or eggs in the ovaries of dissected moths. Most workers found that spring-brood moths were less fecund than those of later broods under insectary conditions. List and Yetter (1927) obtained equal numbers of eggs in the ovaries of all broods and concluded, like most other workers, that the lower fecundity of the spring brood was due to the lower temperatures of spring and early summer. The moths usually lay most of their eggs early in their life-span (Isely and Ackerman, 1923; List and Yetter, 1927). Most investigators found that confined moths, especially when caged in pairs, oviposited irregularly and many moths did not do so at all, partly at least because they did not mate. Hence, probably none of the published records of oviposition truly reveal either potential reproductive capacity or actual capacity in the orchard. The rate of multiplication in orchards suggest that estimates of fecundity determined from caged moths are too low. In the Niagara Peninsula a small population of overwintered larvae (admittedly estimated because dependable figures are lacking) can cause a heavy infestation by first-brood larvae, and a relatively few of this brood that escape the effects of sprays can produce a devastating second brood. 27 fe ait oN pe i hr a Diapause Several early workers (e.g. Shelford, 1927; Garlick, 1948) tried to correlate the entry of larvae into diapause with such factors as temperature and moisture, but they found that the time of entry was more related to | calendar date than to the environmental conditions they investigated. The problem was finally solved by the discoverey of the dominant effect of photo-periodism (Dickson, 1949; Dickson et al., 1952), modified by tem- perature. At 75.2°F., 15 hours of light in a 24-hour day, or continuous light, during their feeding period in apples completely inhibited diapause in larvae. Reduction of the photoperiod increased the proportion of larvae — entering diapause and all did so at 12 hours. Increasing the temperature decreased the incidence of diapause under a particular photoperiod; at 86° F. only about 75 per cent of the larvae entered diapause under a 12- hour photoperiod. The previously mentioned ability to select from a single original strain, lines differing in voltinism (Garlick, 1948) indicates that the thresholds of response to diapause-inducing factors are genetically controlled. Inherit- ed characteristics probably account for regional differences in the response to diapause-inducing factors, a rearing temperature of 80°F. completely inhibiting diapause in larvae from the Okanagan Valley of British Columbia (Proverbs and Newton, 1962a). These authors obtained anomalous respon- ses at very high temperatures, many male larvae reared at 75-85°F. under continuous light entering diapause when held at 90° F. after maturity. Nutrition may also be a factor in inducing diapause; Heriot and Waddel (1942) found that larvae reared on immature apple pulp had a considerably higher incidence of diapause than larvae reared under similar conditions on immature apple seeds. Townsend (1926) found that diapause was broken more quickly at 50° F. than at 32° F. and was not broken at 71.6° F. Workers at Vineland Station (unpubl.) found that larvae held in a refrigerator at about 40° F. usually, but not always, pupated sooner than larvae kept out-of-doors until February or March at temperatures that averaged below freezing. Balachowsky (1936) in France broke the diapause of larvae collected in December by exposing them at 75 per cent relative humidity successively to 24.8° F. for eight days, to 14° F. for eight days and then to 77° F. for 16 days, when they pupated and produced adults 10 days later. Townsend (1926) said that soaking the cocoons frequently in water hastened pupa- tion and increased the proportion that transformed successfully. Peterson and Haeussler (1928), Theron (1943), and Andrewartha (1952) could not ~ hasten pupation by soaking, but several workers, including those at Vineland Station (unpubl.) feund that soaking increased survival. Thus inhibition of water, whereas probably not effective in terminating diapause, aided pupation and adult emergence. However, it is not essential for pupa- tion in the codling moth as it is in some other lepidopterous larvae (Lees, 1955). Codling moths may emerge in very large numbers in dry storage rooms but are often considerably later than those emerging in the orchards, probably delayed by the lower temperatures of the storages. Theron (1943) claimed that forcing diapausing larvae to spin new cocoons several times caused them to pupate soon, but this result was not obtained in limited trials at Vineland Station (unpubl.). In a later paper Theron (1947) said the respinning induced pupation only in larvae that had been in diapause for a month or two. Andrewartha (1952) could not ' break diapause by this method. - 28 Vapours of organic fat solvents and other chemicals that break diapause in some other larvae have no effect on the codling moth (Theron, 1943; Hastings and Pepper, 1944). A number of workers, such as Hammer (1912), reported that some larvae remain in diapause until after a second winter but most workers failed to get moths from such larvae. Yothers and Carlson (1941), how- ever, obtained many moths from beinnial larvae in the soil in California. Andison and Evans (1943) felt that these authors had not unequivocally proved their claim, but there seems to be little reason to doubt it. In three successive years Garlick (1948) found that from 0.1 to 1.7 per cent of the larvae overwintered twice in corrugated paper strips in an insectary and obtained moths from them. In Yugoslavia 7 per cent of the diapausing larvae remained for a further year and 32 per cent of these biennial larvae emerged as moths (Lekic, 1950). A female emerging in 1926 from a larva maturing in 1924 laid eggs that ultimately produced adults (Hall, unpubl.). Although Siegler and Brown (1928) failed to get moths two years later from larvae artificially refrigerated at 32° F. during their second summer and winter, Garlick (1948) obtained them with low mortality when the larvae were refrigerated at 38-40° F. during their second summer and stored outside during both winters. | Habits and Behaviour Young Larvae In the laboratory the first-instar larvae are weakly photopositive in bright light but not in direct sunshine (McIndoo, 1928, 1929). When on a flat surface with cubes of apple and cork the larvae wandered aimlessly until within a few millimeters of the cubes, when they often turned and went directly to them. They moved more often toward apple than toward cork. which suggested that odour attracted them. Hall (1934), using newly hatched larvae placed on leaves on the trees or on cut twigs, concluded that the larvae found the fruit through random movements. Garlick (unpubl.) observing larvae hatching naturally from eggs on leaves in the orchard believed that their movements were more oriented. After hatching on a leaf, the larva first explored both sides of it thoroughly, and if the leaf touched a fruit this was entered. If no fruit were encountered the larva descended the peticle to the twig. If it encoun- tered another petiole the larva ascended it a short distance and returned to the twig. If it encountered a fruit peduncle the larva continued to the fruit and attempted to enter it. As most eggs are deposited on leaves near the fruits, most larvae do not need to travel far, but Steiner (1939) found that some larvae entered fruits as far as ten feet from the point of hatching. Many larvae enter the fruit through the calyx end. Others take advan- tage of blemishes such as scab lesions or entry holes of other larvae and still others penetrate unbroken epidermis on the side of the fruit. The proportions entering through the calvx or through the side vary consider- ably ; older references, such as Hall (1929), indicate that more of the first- brood larvae than of the second or later broods entered through the calyx. Garlick (1938) cited figures supporting the general belief that the propor- tion of calyx-entering larvae had decreased in Ontario since early in the century. Before entry into the fruit the larva first spins a thin covering of silk over the site. As noted by Simpson (1903) and many others the larva dis- 29 ecards the bits of epidermis bitten out as it penetrates the apple. The entrance to the burrow is closed with a few strands of silk. The larva may feed for a short time just beneath the epidermis but it usually penetrates toward the core, pushing its excrement back through the entrance. At the core it eats the seeds; Heriot and Waddel (1942) showed that larvae feeding on immature seeds developed considerably faster than larvae feed- ing on the pulp of the fruit. Several days before maturity the larva enlarges the entrance burrow or cuts a new one to the surface, through ‘which it easts out its excrement. Larvae at any stage of growth may leave an apple and enter another, sometimes a considerable distance away. This movement occurs especially when the first apple fails to develop (Garlick, 1940). A number of workers reared larvae on apple leaves for various periods, and Speyer (1932) and Heriot and Waddell (1942) obtained moths from them but the moths did not produce eggs. Marshall (1940) found that larvae matured when feeding on fruit spurs, young shoots, wooly aphid galls, and the bark of older twigs on a caged tree without fruit. Gentner (1940) found that larvae matured under natural conditions in the fruit spurs of Bosc and Anjou pears. At Vineland Station, Putman (unpubl.) found almost mature larvae in the spurs of Bartlett pear, and others reached at least the second instar by feeding externally on the epidermis of pears where the latter touched another fruit or a leaf. The epidermis of immature pears is underlaid with stone cells that newly hatched larvae find difficult to penetrate. Boyce (1935) quoted R. H. Smith, who found that young larvae also have difficulty in entering walnuts. Many workers noticed that more than one larva seldom reached maturity in a single apple, though many might enter it; the average number of larvae maturing per fruit was always less-than two. They attributed the elimination of the surplus larvae to cannabalism. Putman (unpubl.) ob- served direct evidence of cannibalism while dissecting artifically infested apples in insecticide tests. Mature Larvae When fully grown the larva leaves the fruit, usually at night (Garlick and Boyce, 1940), and searches for a cocooning site. In the Niagara Penin- sula a large portion of the first brood and a small portion of the second brood of larvae leave the fruit after it has fallen (Garlick and Boyce, 1940). LeBaron (1873) saw larvae dropping to the ground or lower limbs on strands of silk. Few other workers have observed this habit, but it has been inferred because larvae were found on portions of limbs isolated above and below by adhesive barriers. Other larvae descend by crawling; Van Leeuwen (1929) and Garlick (1948) described extensive wanderings over all parts of the trees. The larvae may spin their cocoons on any part of the tree including very small limbs. Authors have found widely different proportions of the larval population on different parts of the tree; the proportion on the trunks varied from 77 (Sherman, 1933) to 16 per cent (Woodside, 1941). Garlick (1948) examined five trees at Vineland Station and found 46 per cent of the larvae on the tops, 13 per cent about the main crotches, and 41 per cent on the trunks. Obviously the distribution of larvae on the trees cannot be generalized because it will vary with the distribution of rough bark and cavities that depends on the age and care of the trees, and possibly also with frequency of rain as discussed farther on. Garlick (unpubl.) fre- quently collected more than a thousand larvae per tree from trunk bands, 30 yet careful search of interspersed, unbanded trees in the same orchard never yielded more than 200 larvae per tree. Apparently the numbers hiber- nating on the trees were limited by the availability of suitable sites. Larvae may reach the ground by dropping or crawling from the trees or by emerging from fallen apples. If the orchard floor is free of larger debris most of those not eliminated by predators eventually reach the trunks of trees, often travelling a considerable distance. Van Leeuwen (1929), Cutright (1937), Garlick (1948), and others trapped many larvae on trunks isolated above by adhesive barriers or on trees that bore no crop and consequently had few or no indigenous larvae. Few larvae spin cocoons in the soil, fallen leaves, or sod (Chandler, 1928; Headlee, 1929, 1932a; Steiner, 1929; Woodside, 1941; Gould and Geissler, 1941) at least in eastern North America, but Newcomer and Whitcomb (1924) and Yothers and Carlson (1941) reported many cocoons in the soil near the bases of the trees near Yakima in Washington State, Perhaps the drier soil in the West allows more larvae to enter it. Putman (unpubl.) in the Niagara Penin- sula noted that many larvae spun up on the trunks at the soil level in dry seasons but few or none did so when this area was wetted by frequent rains. Also, wet burlap bands on posts trapped many fewer larvae than dry bands (Cutright and Houser, 1929). Larvae may abandon their cocoons if they become very wet (Peterson and Haeussler, 1928). Larvae frequently spin cocoons on the orchard floor on larger objects such as large weed stems, pieces of wood, or dried fruit (Steiner, 1929; Garlick, 1948; Putman, unpubl.). Steiner (1929a) liberated mature larvae on a smooth orchard floor. After moving away from the sun for several yards, they oriented toward the nearest tree and continued to it even if it was toward the sun. In other experiments they moved toward any upright object. Larvae leaving the fruit in bright daylight took shelter under fallen leaves or other debris and later, as light intensity decreased, proceeded toward a tree or some other object suitable for spinning. Larvae released at night appeared to move at random. MacLellan (1960) studied the movements of larvae tagged with radio- phosphorous. Most fully grown larvae released on fruit on the trees spun up on the trunks. Those released on the orchard floor in the open moved at an approximate angle of 135° to the sun, whereas those released in shade under sunny conditions, during cloudy weather, or at night sought the darkest shadows of various objects. Four per cent of larvae released in the sun, 35 per cent of those in the shade, 64 per cent of those in cloudy weather, and 68 per cent of those at night found tree trunks. Siegler and Plank (1921) and others found that more larvae spun up under dark- coloured bands on the trunks than under light ones. Whereas the earlier instars are indifferent or only weakly responsive to light, gravity, and contact, mature larvae about to spin their cocoons are strongly photonegative, geopositive, and thigmopositive (McIndoo, 1928 1929). The geopositive reaction cannot be very strong, for larvae often ascend the trees to spin cocoons. The usual assumption that both diapausing and non-diapausing larvae use Similar sites for cocoons was questioned by Paillot (1986), who believed that the proportion of diapausing larvae among those Spinning up under corrugated cardboard bands was higher than in the bark. If this is generally true, some published figures on the extent of the second generation are erroneous. ol Cocoons of non-diapausing larvae have rather thin walls and an exit tube that leads to the outside and is closed by a thin partition at the inner end. Overwintering cocoons of diapausing larvae lack exit tubes and have thicker walls containing more of the masticated substrate. In the spring before pupating the larva cuts an opening in the end of the cocoon and constructs an exit tube with a partition at the inner end. A few larvae leave their hibernating cocoons in the spring and build new ones elsewhere (Melander and Jenne, 1906). ; Adults There is general agreement that moths emerge from pupae almost entirely during daylight; some authors found peak emergence occurred in the forenoon and others in the afternoon (Quaintance and Geyer, 1917; Siegler and Plank, 1921; Selkregge and Siegler, 1928). No doubt the time is affected by temperature and light intensity. Van Leeuwen (1929) observed that most copulations occur at 7 to 9 p.m. Siegler and Plank (1921) found that captive moths mated during most of the day ; they remained in copulo up to 30 hours and seldom less than one hour. Borden (1931) cbserved moths mating in the orchard during the evening flight period; they remained in copulo for 20 min. to one hour and 20 min. The males appeared to be attracted by the movement of the females. Patterson and Armstrong (unpubl.) at Vineland Station lured males into traps by using virgin females, proving that the females produce a volatile | sex lure or pheromone. Females that had been confined with males were also attractive to other males, but it was not shown that all the females had been inseminated. Trials with benzene or xylene extracts of female abdomens were inconclusive. Both males and females may mate more than once; females from British Columbia orchards had an average of about two spermatophores i in the bursa copulatrix, each representing a successful mating (Proverbs, 1962). Despite early reports to the contrary, codling not are attracted to light (Yothers, 1928) though they are considerably less responsive than many other Lepidoptera, possibly because they are essentially crepuscular rather than nocturnal. Peterson and Haeussler (1928a) found that the shorter wave-lengths from blue to ultraviolet were most attractive. Red was unattractive. Blue of about 43850 a was the most attractive of several colours tested by Herms and Ellsworth (1934). Headlee (1932) reported orchard observations that mercury vapour light rich in ultraviolet appeared to stimulate oviposition whereas red light promoted an abnormal type of moth activity but apparently not oviposition. Marshall and Hienton (1935) found that mercury vapour tubes were more attractive than several types of incandescent bulbs. Marshall and Hienton (1938) concluded that at- tractiveness was influenced by intrinsic brilliance, the size of the luminous area, and colour of light. The relation of movement of retinal pigment to light attraction is reviewed under physiology. Light traps, especially of the electrocuting ee were used by a number of investigators to study the daily and seasonal flight periods. However, they apparently do not give an accurate picture of daily flight. They are less effective during the early part of the flight period which be- gins before dark; Hamilton and Steiner (1939) found lights were ineffec- tive until natural light intensity fell to 0.2 foot candles. Patterson (1937) captured most moths during the second half hour after sunset. Also, Eyer (1934) and Parrot and Collins (1934) compared the moth catches in bait 32 and light traps and concluded that the lights artificially prolonged moth flight by raising the light intensity in the orchards. Most authors, such as Herms and Ellsworth (1934), Marshall and Hienton (1935), Worthley and Nicholas (1937) and Groves (1955) caught more males than females in light traps but Parrot and Collins (1934) caught more females. The latter authors caught marked virgin females in traps the same day they were liberated. Collins and Machado (1943) re- viewed earlier work with light traps and gave additional data. Early investigators found that moths were attracted to fermenting solutions of fruit juices, sugars, and syrups. Bait traps, especially those containing a one-to-nine solution of molasses in water, have been widely used to study the flight periods and for timing spray applications, and experimentally as a means of control. Various essential oils and other compounds were tested as additions or substitutes for the fermenting solutions and some were more attractive (Eyer and Rhodes, 1931; Eyer and Medler, 1940; Eyer, 1945; Eyer and O’Neal, 1949; Van Leeuwen, 1943, 1948; Dethier, 1947). Garlick (unpub!.) tested some of these materials at Vineland Station and concluded that the simple molasses-water solution was sufficiently attractive for determining flight periods. Eyer (1934) caught more males than females in bait traps but most other authors, e.g. Parrot and Collins (1934), Marshall and Hienton (1935), and Worthley and Nicholas (1937) caught more females. Steiner (1929) caught more males in cool weather and more females in warm weather. By comparing the catches with those from rotary nets Alexander and Carlson (1943) showed that bait traps gave an accurate measure of flight activity over the period of their tests. Hamstead and Gould (1950) compared the numbers of oocytes in trapped females with the numbers in caged moths of known ages and concluded that the trapped moths had laid many eggs before capture. However, confined moths, including those of these authors, often do not Oviposit normally so their contention cannot be considered proved. The extent to which food reserves have been depleted, as determined by analyses for fat and nitrogen, might give a more reliable indication of the age of trapped moths. Dethier (1947) concluded that essential oils attract the moths by acting as oviposition stimuli, whereas fermentation products are primarily feeding stimuli. Van Leeuwen’s (1947) finding that the odours both of molasses bait and of apples increased the number of eggs laid by caged © moths suggests that some fermentation products also produce an oviposition response. Although the adults are not known to feed in orchards they may still retain some feeding response that can be aroused by certain odours. Siegler and Plank (1921) believed the moths tended to be sedentary, though they followed some released ones for more than 1000 feet in con- tinuous flight in the orchard. Other authors released moths marked with dyes and recaptured them with bait traps or nicotine-lime dust. Worthley (1982) recaptured 50 per cent within 200 feet of the release point and more than 90 per cent within 500 feet. Van Leeuwen (1940) found that the moths travelled an average of 143 feet before recapture but a few travelled up to one-quarter mile. Very few moths released outside the treated area were captured. Steiner (1940) concluded that the average distance travelled by a moth in his experiments was at least 200 feet and the greatest distance 2,079 feet. The capture of marked moths on the far side of an area filled with bait traps suggested that some made continuous long distance flights on which they by-passed intervening traps. It is of interest that long- 33 distance flights have been demenstrated in another tortricid, the European pine shoot moth, Rhyacionia buoliana (Schiff.) (Green and Pointing, 1962). As some of the authors cited pointed out, their data suffer from the usual deficiencies of the mark-and-recapture technique; in particular the moths may be captured before they disperse to their full extent. The evidence suggests, however, that most moths move only a few trees’ distance but occasionally fly considerably farther. The generally limited dispersion of the moths was confirmed by the work of Wildbolz and Baggiolini (1959) who released large numbers of mature larvae and pupae at one point in a lightly infested orchard in Switzerland. Subsequent fruit infestation was very heavy immediately about the release point but dropped to one-tenth of that rate at about 50 yards and was normal at 150 yards. The rate decreased fastest in the direction of the wind. Recently developed techniques for the study of dispersal such as the use of fluorescent dyes and radio-active tracers have not been applied to the codling moth, nor have data been subjected to modern mathematical treatments developed for the mark-and-recapture method. The dispersal of DDT-resistant moths from the orchard in which they first appeared at Vineland Station is of interest (Dustan, unpubl.). About two years (two or three generations) after resistance became very high in the original orchard it became appreciable in another orchard about 200 yards away, the distance being partly bridged by a pear orchard, and after another generation, in another orchard about 600 yards distant in another direction. Although the greater larval infestation of fruit in the tops of apple trees is usually attributed to inadequate spraying, the greater numbers of eges (Summerland and Steiner, 1943; MacLellan, 1962) and of infested fruits (List and Newton, 1921; Woodside, 1944; Richardson and Du Chanois, 1950) in the tops of unsprayed trees must reflect a similar dis- tribution of ovipositing moths. Borden (1931) observed that the moths tended to fly about the tops of the trees. The moths lay their eggs singly. Hall (1929) and others made the general statement that in the spring most eggs are laid on the upper surface of the leaves, in midsummer on the under surface, and later chiefly on the fruit. Such a distribution is not supported by the detailed counts made by others; Caesar (1914) found that 80 per cent of the first-brood eggs were laid on leaves, mostly on the upper surface, 18 per cent on the fruit, and 2 per cent on the twigs; he did not give figures for later broods. Summerland and Steiner (1948) found only 6 per cent on the fruit over the whole season, the proportion being somewhat greater late in the season. Garlick (unpubl.) recorded the position of from 380 to 840 eggs in each of four years; the percentages on leaves ranged from 85 to 95; on fruit, 5 to 13; and on twigs, 0.2 to 1.3. Over the four years 55.2 per cent of those on the leaves were on the upper surface. McLellan (1962) found 53 per cent on the upper surface of the leaves, 30 per cent on the lower surface, and 17 per cent on the fruit. There is general agreement that most eggs are laid on leaves near fruit, though a few may be laid on distant parts of the tree. Wildbolz (1958) showed that the odour of apples induced the moths to oviposit in their vicinity. Several workers found that the presence of apples increased oviposition by caged moths. Most workers found that captive moths laid most of their eggs during the late afternoon and early evening, for example, 79 per cent from 3 to 9 p.m. (Siegler and Plank, 1921) ; mostly from 3 to 9 or 5 to 8 p.m. according to the brood (Selkregg and Siegler, 1928). Doubt is cast on the details of 34 some of these results by Garlick’s (unpubl.) observation that the numbers of eggs laid by caged moths are seriously reduced by disturbance during the oviposition period, as by periodic changes of the substrate on which the eggs are laid. However, the general conclusion that oviposition is most intense during a short period near sunset is not affected. The time of oviposition in the orchard has usually been investigated through study of flight activity, either visually or by traps, on the assump- tion that the two processes are synchronous. This assumption is supported by the behaviour of caged moths and by rather scanty observation of actual Oviposition in the orchards (Borden, 1931; Headlee, 1932; Collins, 1934), though Wildbolz (1958) found that eggs were laid on a small caged tree throughout the day. As in the cages, moth activity in the orchards was most intense during a short time at dusk. Eyer (1934) found that 15 to 20 per cent of the moths had another flight period at sunrise in New Mexico. Parrot and Collins (1934) in New York also detected a morning flight. Patterson (1937) in Ontario found that morning flight occurred on some days but not on others. The extent of oviposition during morning flights is not known. The environmental conditions that affect flight and oviposition are discussed under ecology. : Biological Control Parasites and Predators The first report of parasites of the codling moth in Ontario was by Brodie (1907) who listed “Pimpla pteralis” (Scambus pterophort Ashm. = Pimpla pterelas Auctt.) as a primary parasite and “Dibrachys boncheanus” (D. cavus (Walk.) =D. boucheanus (Ratz.) as a secondary parasite. Boyce (1941) in the Niagara Peninsula found Trichogramma minutum Riley (—T. emryophagum Htg.) to be the only egg parasite, attacking up to 52 per cent of the eggs but usually a much lower percentage. As other species in this taxonomically difficult genus have been recorded from C. pomonella in America and elsewhere, all will be referred to as Tricho- gramma spp. in this review. Ascogaster quadridentata Wesm. (=A. carpocapsae (Vier.) ), a European species accidentally introduced to North America, was by far the most important parasite of the larvae. Its inci- dence of attack varied greatly from year to year but at times reached 25 per cent. Hyperparasitism on A. quadridentata by Perilampus fulvicornis Ashm., P. tristis Mayr, and Perilampus spp. sometimes reached 72 per cent. Other larval parasites reared in very small numbers were Dibrachys cavus (Wlk.) (also a hyperparasite on A. quadridentata), Macrocentrus delicatus Cress., M. instabilis Mues., M. ancylivorous Roh., and Phanerotoma sp., later identified as P. fasciata Prov. by Walley (1951) who stated that all records of P. tibialis (Hald.) and Phanerotoma sp. from the codling moth are actually of P. fasciata. Pupal parasitism was negligible, the only species reared being D. cavus, Hupelmus cyaniceps Ashm. (also a hyperparasite on Macrocentrus spp.), Pimpla annulipes Brullé (=P. inflata Townes), and EKurytoma sp., later recognized as a hyperparasite (Boyce, 1948). The only insect predator of any importance was Tenebroides corticalis Melsh., which as both larva and adult attacks codling moth larvae and pupae in the bark. Some larvae were destroyed by the ant Solenopsis molesta (Say) and the spider Agelena naevia Walck. The most effective predators were the downy woodpecker, Dendrocopos pubescens (L.), and the hairy wood- pecker, D. villosus (L.), which together destroyed from 67 to 95 per cent of the hibernating larvae on the trunks of some trees. Larvae on the smaller branches did not appear to be attacked. 35 t a ike i Boyce (1943) gave further data on parasitism by A. quadridentata and showed that in some years parasitism by this species was considerably — higher in unsprayed parts of an orchard than in parts sprayed with lead arsenate and other materials. In laboratory tests lead arsenate, especially in combinations with sulphur fungicides, inhibited oviposition by the para- site in the eggs of the host but did not shorten the life of the adult parasties. In the United States Cox and Daniel (1935) and Driggers and O’Neill (1938) found that lead arsenate was detrimental to parasitism by this species. In a subsequent paper Boyce (1948) recorded Mastrus carpocapsae (Cush.) (=Aenoplex carpocapsae Cush.), Temelucha minor (Cush.), Cryptus albitarsis (Cress.), Glypta sp., and Aritranis sp. (—Hoplocryptus sp.) from codling moth larvae and J toplectis conquisitor (Say) and Pimpla annulipes Brule... (= Coccygomimus inflatus (Townes)) from pupae. E. cyaniceps was both a primary parasite on C. pomonella and a secondary on P. annulipes. This paper also listed parasites of the moth in other provinces. Many collections of larvae by Garlick and Putman (unpubl.) confirmed Boyce’s findings. Parasitism of larvae by A. quadridentata ranged up to 32 per cent in some orchards; that by cther species was negligible. Boyce (1943a) showed that the form of A. quadridentata attacking the codling moth in Ontario differed in colour from the form attacking the pea moth in Europe and that the two forms were interbred with difficulty in the laboratory. Specimens from the codling moth in both Ontario and England were identical in colour. Many authors noted that larvae parasitized by A. quadridentata are much smaller and paler than normal ones. The ichneumonids Apistephialtes caudata (Ratz.) and Cryptus sex- annulatus Grav. were introduced from France and after propagation at the Dominion Parasite Laboratory, Belleville, were released in some apple orchards in the Niagara Peninsula, A. caudata from 1940 to 1945 and C. sexannulatus from 1941 to 1945. Both species were recovered after release but they failed to become permanently established (Simmonds, 1944; Boyce 1941, 1948, 1949; Naphtali, 1941). In 1943 and 1944 small numbers of Elodia tragica (Meig.) and Pristomerus vulnerator Panz. from England were released in Ontario but apparently did not become established (Boyee, 1949). A. quadridentata, A. caudata and C. sexannulatus were introduced to British Columbia but only A. quadridentata became established (McLeod, 1954). MacLellan (1958, 1959) found that an average of 52 per cent of the larvae overwintering on the trunks in Nova Scotia were destroyed by the downy and hairy woodpecker over a seven-year period. In many orchards woodpeckers alone reduced the overwintering population to a level where no insecticidal control was necessary. It is exceedingly doubtful whether this ever happens in southern Ontario where a larger second generation allows the moth to multiply much more rapidly. MacLellan also found that woodpeckers destroyed a smaller proportion of larvae parasitized by A. quadridentata than of normal larvae. Birds destroyed more hibernating larvae than any other factor in Quebec (LeRoux, 1959; Mailloux and LeRoux, 1960). MacLellan (1960) found that 94 per cent of larvae fy ced with radiophosphorous that spun cocoons on the ground were destroyed by pre- dators within six weeks. Low survival of larvae on the ground was reported by several workers in the United States, such as Gould and Geissler (1941), presumably due to predation. 36 Garlick (unpubl.) surmised that mice destroyed moth larvae on the orchard floor, either before or after they had made cocoons. This is very probable in view of the weli-known efficiency of mice and shrews in de- stroying cocoons of forest insects, particularly sawflies. However, the mouse population of orchards must be kept to a minimum to prevent them girdling the trees. In the Niagara Peninsula skunks, Mephitis mephitis L., often destroy larvae in cardboard bands on the trees and probably destroy some found wandering or spun up on the ground. Garlick (unpubl.) determined the fate of from 384 to 807 eggs each year from 1951 to 1953 and in 1955 in an unsprayed orchard at Vineland Station. Trichogramma sp. attacked 29, 17, 13, and 10 per cent and pre- dators attacked 4, 8, 9, and 16 per cent in the respective years. Larvae of Chrysopa carnea Steph. (—plorabunda Fitch) and C. rufilabris Burm. were by far the most abundant predators. They were seen feeding on the eggs in the orchard and Putman (unpubl.) found they did so readily in the laboratory. Other predators seen attacking the eggs were Haplothrips fauret Hood and the mite Anystis agilis Banks. It should be noted that this orchard had previously been sprayed with DDT and parathion, which had exterminated most predacious members of the fauna. Predacicus mirids, formerly common in old orchards, had just begun to appear near the end of the experiment. MacLellan (1962) in Nova Scotia found 14.4 per cent of the eggs were destroyed by predators, of which four species of miridS were most abundant. He also obtained circumstantial evidence that the mirids attack newly hatched larvae. Downe and West (1954) reported use of the precipitin test for de- tecting codling moth predators. Many authors in the United States have mentioned parasites and pre- dators, more or less briefly. Trichogramma spp., A. quadridentata, and T. corticalis appear to be more or less ubiquitous throughout the host’s range in eastern North America but nowhere do they exercise an appreciably greater degree of control than they do in Ontario. Lloyd (1944) studied parasites in California and reviewed previous work done elsewhere in the United States. Perhaps the most extensive study of biological control factors affect- ing the codling moth in the United States was that of Jaynes and Marucci (1947) in West Virginia. Trichogramma sp. attacked especially the first- brood eggs and Leptothrips mali (Fitch) those of the second brood. A. quadridentata was the most prevalent parasite of the larvae but parasitism in general was lower than in Ontario. Ants were considerably more effec- tive predators of mature larvae than they are in Ontario, and carabids were also of some importance. Both parasitism and predatism were depressed in orchards sprayed with nicotine and lead arsenate. Summerland and Steiner (1943) reported that 32 to 43 per cent of the eggs were destroyed by Tvichogramma sp. and 19 to 23 per cent by predators, chiefly chrysopid larvae. Contrary to the experience of Vineland Station workers, Jaynes and Marucci (1947) could not induce chrysopid larvae of unstated species to feed on codling moth eggs in the laboratory. Parasitism of the codling moth has been extensively studied in South Africa, Australia, and South America; several indigenous parasites are present and A. quadridentata was successfully established in some areas, but parasites are generally of little importance in these continents. Few intensive studies of natural control of the codling moth have been made in Eurasia. Rosenberg (1934) and Simmonds (1944) carried out - 37 detailed studies in France: Lekic (1950) mentioned parasites of mature larvae in Yugoslavia, and other authors gave brief accounts of parasitism in other parts of Europe. Nevskii (1937) studied parasites in Central Asia. The most effective and generally distributed are Trichogramma spp. and A. quadridentata and other species of Ascogaster, but nowhere do they seem to be particularly effective. The high intensity of infestation by the codling moth in many of the warmer apple-growing regions of Europe and Eastern Asia, even where apples are grown under primitive conditions, is presumptive evidence that effective biotic control factors are lacking. This lack in its original home suggests that the codling moth is a singularly unfavourable subject for biological control in other continents. Only near the northern limits of apple culture, as in Nova Scotia where climate severely restricts its reproduction, can presently known biotic factors hold codling moth attack to commercially acceptable levels. Diseases Boyce (1941) mentioned a disease, apparently bacterial, of larvae in the Niagara Peninsula. Stephens (1952) subsequently isolated several strains of Bacillus cereus Frankland & Frankland from larvae from the Niagara Peninsula and elsewhere in Canada and the United States. They proved to be pathogenic to codling moth larvae by either injection or ingestion. Bacterial diseases do not appear to be an important mortality factor of codling moth larvae. Boyce (1941) also mentioned fungal diseases and Garlick and Putman (unpubl.) frequently noticed diseased mature larvae on the trunks, particu- larly in wet situations, but the importance of these diseases in Ontario was not carefully assessed. Most diseased larvae were found under burlap bands used repeatedly so that inoculum might have built up on them. The fungi were not identified but the well-known Beauveria bassiana (Bals.) Vuill. (=B. globulifera (Speg.) Pickard) was recovered from the codling moth in Nova Scotia (Pickett. and Patterson, 1953; MacLeod, 1954). It has a very wide host range and is widely distributed in Europe and America. In West Virginia Jaynes and Marucci (1947) showed that it could infect codling moth larvae of all ages, and isolated it from larvae that had died while entering the fruit. In California Mickelbacher et al. (1950) found up to 70 per cent of overwintered larvae infected, especially in moist situa- tions on the trunks. Hirsutella subulata Petch infected up to 40 per cent of the mature larvae in some of the United States (Charles, 1941). | No records of natural infection of the codling moth by Protozoa were seen but larvae could be experimentally infected with the microsporidians Nosema destructor Steinhaus and Hughes and Plistophora EE Ss Steinhaus and Hughes (Steinhaus and Hughes, eae Nematodes There are several old records of Mermis sp. parasitizing codling moth larvae in North America. Dutky and Hough (1955) found that another nematode, Neoaplectana n. sp., or DD136, and an associated bacterium caused considerable mortality of larvae in Virginia. This species was later found to have a wide range of insect hosts and has been tested as a control agent for the codling moth (Welch, 1962). Ecology Effect of Meteorological Factors on Rate of Development Most work on the relations between weather factors, particularly temperature, and rate of development of the codling moth was aimed at 38 forecasting the optimal times for application of sprays. Glenn (1922) de- veloped the use of day degrees for calculating the developmental periods of the egg, larva, and pupa under natural, fluctuating temperatures. He summed the daily excess of temperature over the threshold of development, which differed among the stages of the moth, and subtracted twice the excess of temperature over that at which the developmental rate was maximal. In this manner he obtained a ‘‘thermal constant” for each stage of the moth. Headlee (1928, 1931) also advocated the use of the thermal constant, checked by observation of actual moth emergence, for timing spray applications. The day-degree concept has been widely criticized both on theoretical grounds and because actual development often differs con- siderably from predictions based on the “thermal constant’’, as admitted by Glenn and Headlee. Nevertheless it is useful for forecasting the approxi- mate times of some entomological events. | In a monumental work Shelford (1927) extended and modified Glenn’s work by including the effects of humidity and by expressing the stage of development in ‘developmental units”. The method is too complicated to be explained here. Despite the magnitude of this effort the procedure is so complex that it has had little practical use, and because it is largely empirical has had little influence on ecological theory. Proverbs and Newton (1962) expressed the stage of pupal development in developmental units. Honkins (1938) briefly considered the prediction of seasonal events in the moth’s life-history in relation to his theory of bioclimatics. Development of all stages was about seven to eight per cent more rapid at variable outdoor temperatures than at constant temperatures equal to the means of the variable ones (Shelford, 1927). The time of spring emergence of moths varies considerably with the situation of the cocoons, those exposed to the sun on the southern side of tree trunks or other objects emerging first (Peterson and Haeussler, 1928; Hall, 1929; Evenhuis, 1953). By using infra-red radiation in the laboratory to simulate insolation Post and de Jong (1958) obtained marked differences in the times of emergence from pupae placed at different points about a section of trunk. Flight and Oviposition Nearly all authors agree that Oviposition of captive moths is virtually stopped at temperatures below about 60 to 62° F. (Isely and Ackerman, 1923; Hall, 1929; Cutright, 19387; Isely, 1938; and others). Parker (1959) did not obtain oviposition below 65° F.. In Switzerland Klingler et al. (1958) reported the threshold and optimum temperatures for oviposition to be about 53.6 and 68° F. respectively, which are decidedly lower than those given by North American investigators. Isely (1938) found that oviposition increased with temperature to an optimum of about 80° F. A further in- crease in temperature reduced oviposition in many moths but this effect was partly masked by a very high rate among a few. Exposure to high tem- peratures (unspecified) as larvae, pupae, or adults tended to sterilize the moths and many of their eggs were infertile. Proverbs and Newton (1962) likewise found that egg production was reduced in moths exposed to high temperatures at some stages of development. The lower temperature threshold for flight in the orchards is also about 60° F. (Eyer, 1934; Patterson, 1937; and others), though Parker (1959) observed practically no flight below 65° F. Borden (1931) found some differences in threshold temperatures among moths from different districts. Eyer (1934) found that temperatures above 80° F. tended to 39 - abe ngs} ee A inhibit flight. Russ (1961) in Austria said that the optimum temperature for flight was 68° F’., which appears to be remarkably low. Garrett (1923) used late afternoon and evening temperatures to predict when sprays should be applied. Borden (1931) found flight in orchards to be greatest ata light inten- sity of 25 to 52 foot candles, though some flight occurred at intensities considerably above and below these limits. Bright sunlight or complete darkness checked it. Eyer (1934) stated that moth activity was greatest — at 30 to 50 foot candles. Headlee (1932) said that flight and oviposition | began at about 30 foot candles and increased as the intensity fell to less than ~ one foot candle. Dickson et al. (1952) said that a decreasing intensity below 50 foot candles stimulated oviposition. Increasing intensity over a similar — range did not promote moth activity in his cages, though as previously noted a morning flight sometimes occurs in orchards when natural light is increasing. He did not obtain as great a rate of oviposition under decreas- ing artificial light as under natural twilight. Other workers have had a similar experience; perhaps the change in the quality of the light that | occurs at twilight is involved. Borden (1931) observed that moth flight in the orchard was checked by very light wind. Oviposition of confined moths was checked by an air current of four miles per hour (Parker, 1959). However, Russ (1961) found that wind below 13 miles per hour had little effect on flight in an Austrian orchard. He studied moth activity with light traps, which as previously noted are not effective during the early part of the daily flight period. Various authors claimed that rain inhibited flight but few gave sup- porting data. Russ (1961) found that less than one mm. of rain slowed or stopped flight. He also found that relative humidity above 74 per cent accompanied by intermittent rain inhibited flight. He found no correlation between flight intensity and atmospheric pressure. Lethal Effects of Low Temperatures The lowest temperature to which eggs are ordinarily exposed in the orchard are unlikely to kill them. Thirty-five days of storage at 30 to 31° F. did not kill all eggs on apples though few survived beyond 23 days (New- comer, 1936). Young larvae that had just penetrated the epidermis of apples did not survive 28 days at 30 to 31° F. Older larvae that had reached the core were hardier; only 59 per cent were killed by the same exposure (New- comer, 1936). When mature, non-diapausing larvae were held at 40° F., 22 per cent survived 117 days and 1.4 per cent survived 147 days (Carlson, 1942). low temperatures on the diapausing larva in the laboratory. Although some of the concepts they used, as of “bound water’, are no longer considered valid (Salt, 1961) they showed that the larva could not survive freezing of its tissues but had considerable ability to supercool. The exact. supercooling limits are not of great interest because mortality from cold is a function of both intensity and duration of exposure, as shown by Hasemann (1942). He found that the zone of fatal low temperature was from about 10 to —15° Ditman et al. (1942, 1943) and Siegler (1946) studied the effects of F.; at temperatures above these limits most larvae survived long exposure and at lower temperatures all were quickly killed. Some larvae were much more cold-tolerant than most. 40 In Washington Newcomer (1920) found that minimum winter tem- peratures between —20° and —25° F. killed about 80 to 90 per cent of the hibernating larvae on the trunks. None survived —25° F. The “great freeze’ of February, 1934, with prolonged subzero tem- peratures throughout southern Ontario, caused extensive mortality of hibernating larvae. At Vineland Station where the absolute minimum was —14° F., 52 per cent of several hundred larvae in glass vials held in canvas bands wrapped about the trunks of trees were killed (Garlick, unpubl.). Mortality of larvae similarly held in 1932 (minimum 2° F.) was 23 per cent and in 1933 (minimum —2.7° F.), 31 per cent. In Norfolk County, where the absolute minimum in 1934 at Simcoe was —24° and the average minimum for February was —0.5° F., the overall mortality of larvae on the trunks was about 50 per cent and was virtually complete for larvae above the snow line (Hall, unpubl.). Al! of 3000 larvae in cardboard strips in a screened insectary were killed. Large numbers of apple trees were also killed in Norfolk County. Winter temperatures at or below the lethal limits for larvae occur com- monly along the northern edge of apple culture in Canada, which may expiain, together with virtual univoltinism, why the codling moth is much less troublesome in these districts. As already mentioned, low winter tem- peratures probably account for the moth’s absence from Manitoba. Mortality of Eggs Parasitism and predation on eggs have been dealt with under biological ecntrol. Mortality of eggs from other causes is generally low. Infertile eges, though common in the laboratory, are scarce in orchards and none of various estimates approach five per cent of the total. About five per cent of the egys disappear, presumably by scaling off the leaves (Summerland and Steiner, 1943). Wyniger (1956) said that relative humidity below 50 per cent had no effect at 77° F. but prevented hatching at 99.6° F. Lekic (1950) claimed that many eggs died when the relative humidity was below 40 per cent but gave no data on temperature. Eggs hatched when contin- uously submerged in water during incubation (Wyniger, 1956), La . rains should not affect them. Mortality of Newly Hatched Larvae Many young larvae fail to enter fruit. Only 48.6 per cent of larvae placed on leaves two to 12 inches from fruits succeeded in entering them (Hall, 1934). On the other hand Garlick (unpubl.), observed over a four- year period the fate of from 234 to 586 larvae per year that hatched in the orchard and found that from 76 to 90 per cent entered the fruit. Hall (1934) stated that larvae could not enter fruit at temperatures below 50° F. whereas Cutright (1931) fixed this threshold at 59° F. Cutright also found that the proportion of successful entries increased with temperature up to 86° F., the highest tested ; 3.8 per cent of the larvae succeeded at 68° F. and 36 per cent at 86°. There appears to be no information on the effects of atmospheric moisture on this stage of the moth. Some authors stated without supporting data that rains removed young larvae from the trees and hindered their entry into fruits. Such an effect is very likely but its importance is un- known. A film of condensed moisture similar to dew impeded movement of newly hatched larvae in the laboratory (Putman, unpubl.). Relation of Weather and Climate to Intensity of Infestation It is well known that warm, dry climates and seasons generally foster 41 higher infestations of the codling moth than cool, moist ones. As previously shown, high temperatures within certain limits speed the rate of develop- ment and so increase the extent of multivoltinism. They also enhance the rate of oviposition and aid the entry of larvae into the fruit. It is less clear how dryness enhances infestations. Rainfall with high humidity inhibits flight and presumably oviposition and probably hinders entry of larvae. Also, moist conditions may aid the spread of disease. However, some authors suggested that part of the cbserved association between dry conditions and high infestation may be the fortuitous result of the fact that warm seasors and climates are usually dry ones among the main apple-growing districts of the continent. Moreover, the moisture relations of orchards may differ from those generally occurring in a climatic region; Proverbs (1957) found that the relative humidity in irrigated orchards of the semi-arid Okanagan Valley averaged higher than in orchards of the Niagara Pen- insula. Webster (1935, 1936) considered the role of variations in local weather ecnditions in a single locality, the Wenatchee Valley of Washington, in causing great fluctuations in the intensity of infestation over a ten-year period. In a later paper Webster (19387) attempted to correlate temperature and rainfall with the incidence of the codling moth at that time in the United States. Temperature, especially in the spring, had the greatest influence in increasing the infestation. He claimed that in the eastern states control was generally not difficult where mean annual temperatures were below 50° F. (The mean annual temperature at Vineland Station is 47.7° F. and control was very difficult during the 1930’s.) In parts of the western states control was difficult where mean annual temperatures were about cr below 50° but these districts were drier. Some districts in Cali- foriiia with moderately high mean temperatures did not suffer severely because their summer temperatures were low. Population Dynamics No comprehensive study of the population dynamics of the codling moth has ever been made, nor have the required sampling methods been worked out. Methods for determining the percentage of fruit injury in control studies are nearly as numerous as Investigators but the statistical reliability of some is uncertain. LeRoux (1961) found no significant dif- ference in numbers of infested fruits between quadrants of trees and usually none between levels. Geier (1961) briefly considered the factors regulating the population density on unsprayed trees in the Australian Capital Territory. The relation between number of fruits on a tree and the number of larval entries agreed with a formula based on the principle of random search. The result was that many fruits had multiple entries (though only one larva usually ma- tured) while other fruits had none. Competition between larvae in the fruit is therefore a density- dependent factor exerting great pressure against population increase well before all fruits are attacked. There is no doubt that this factor is very important in the Niagara Peninsula where uncon- trolled infestations often reach 80 to 95 per cent. Geier (1961) also believed that the availability of shelter for over- wintering larvae on the trees was a complementary governing factor. This conclusion is supported by Garlick’s (unpubl.) observation, noted previous- ly, that the numbers of overwintering larvae on the trees had an upper limit often several times lower than the numbers of maturing larvae. 42 Nutrition Uspenskaya (1936) found that larvae developed most rapidly when fed on both apple pulp and seeds, and more rapidly on seeds alone than on pulp alone. Fertility of the resulting adults depended directly on the rapidity of larval development. Heriot and Waddel (1942) found that the larvae developed most rapidly when fed on immature apple seeds, more slowly on pulp of immature fruits, and slowest on pulp ef mature fruits. The rate of development would appear to be more or less proportional to the protein content of the food. None reached maturity on mature seeds, which were difficult to penetrate. The limited ability of larvae to develop on leaves and twigs has already been mentioned. Larvae developed more rapidly on picked fruits than in fruits left on the tree (Glenn, 1922; Newcomer and Whitcomb, 1924; and others). With- out measurement of the temperature within the fruit one cannot decide whether this difference is due to temperature or to nutritional factors. Theron (1947) attempted to rear the larvae on artificial media but only a few reached maturity. Redfern (1962) also reported some progress in this field. Captive moths drink water freely and require it for reasonable longevity. Various workers fed the moths on sugar solutions but I could not find any experimental results showing that fecundity or longevity were thereby increased. Many authors have shown that the moths oviposit freely when given water alone. The moths do not appear to frequent flowers and have not been seen to feed in the orchard, but their attraction to fermenting baits suggests that they do so. Analyses of the gut contents of moths would be of interest. Physiology and Biochemistry Only isolated studies, none very recent, have been done on the physi- ology and biochemistry of the codling moth. Collins (1934) and Collins and Machado (1935) described the migra- tion of pigment in the iris cells of the compound eyes of the adult in re- sponse to light. Under bright light the pigment moved to a proximal posi- tion and in darkness it returned to a distal position. Only the shorter wave-lengths from about 3000 to 7000 a stimulated movement. The move- ment did not show any innate rhythm. The moths were attracted to bright light only when the eyes were dark-adapted. They usually remained inactive when the eyes were either light-adapted or dark-adapted, and were spon- taneously active (as distinguished from flight to bright light) only during pigment movement, which required about 30 to 60 minutes. The crepuscular flight habits were thus correlated with pigment movement. The pH of the larval crop and ventriculus averaged 8.7 with little if any difference between instars. It was well buffered and little changed by acid apple pulp. Blood of fourth-instar larvae had a pH of 6.7 to 6.8 (Marshall, 1939). Theron (1947) found the enzymes amylase, invertase, and lactase in the larval gut; he could not detect trypsin or lipase by the methods used, but from their general occurrence in other lepidopterous larvae, proteases and lipase are unlikely to be absent. Hastings and Pepper | (1944) studied the fatty materials in diapausing larvae and Ushatinskaya (1949) investigated the changes in fat and water content at various tem- peratures in such larvae. Spooner (1927) studied the catalase content of larvae. Carlson et al. (1944) found that coccons spun on glass contained 22.6 to 30.8 per cent of wax and fat. These materials would have water- repellant properties. A3 Graham (1946) studied the respiratory enzymes in relation to the action of arsenicals and other inhibitors in diapausing larvae. Three types of carbohydrate catabolism, aerobatic oxidative, aerobatic glycolysis, and anaerobic glycolysis, were present. Oxidation via the cytochrome system was normally dominant. Respiration of living larvae was unaffected by variations in oxygen tension between 10 and 100 per cent and the larvae could endure 24 hours of anaerobiosis. Oxygen debt did not occur under anaerobic conditions. Oxygen consumption, especially by the fat-body, rose considerably when diapause was terminated. The concentration of arsenite causing the greatest depression of respiration of the tissues corresponded with the lethal dose. Diapausing larvae survived 132 days in a controlled atmosphere apple storage containing 3 per cent oxygen and 2 to 5 per cent carbon dioxide at 38°F. (Glass et al., 1961). Morphology and Anatomy Praviel (19387) briefly described the external anatomy of the adult; Lopez (1929), the head and mouth parts of the mature larva; Allman (1930), the female reproductive system; and Weismann (1935), the female genitalia, egg, and embryology. Control The Problem The difficulty of controlling the codling moth is proportional to the number of generations. Where the moth is almost entirely univoltine control is relatively easy, but unfortunately this is the situation in North America only along the northern fringe of apple production. As one proceeds south in Ontario the size of the second generation and the consequent problem of control becomes greater. A small proportion of larva producing a second generation can greatly increase the destructive potential of the moth. If we conservatively assume that each female gives rise to 20 larvae, it follows that only 10 per cent of first-brood larvae transforming the same season can produce a second brood of larvae of the same size as the first. More- over, the injury from a second generation may be considerably greater than from a first of equal size because the second occurs when weather is generally more favourable for oviposition and fruit entry. The codling moth problem is therefore particularly acute in southern- most Ontario, in the Upper Austral or Carolinian faunal zone, roughly south of a line from the western end of Lake Ontario to the southern end of Lake Huron. It was also serious along the northern shore of Lake Ontario west of Toronto before urban development eliminated most orchards. Within this southern district the infestation is especially intense in the Niagara Peninsula and Essex County. As early at 1872 infestations of more than 90 per cent were reported from St. Catharines (Anon., 1873). The mature larvae are protected by thick-walled, water-repellant cocoons spun on all parts of the tree and further protected by bark or decaying wood, so this stage is not a particularly favourable point of attack. The moths emerge over a long period; chemical attack on this stage requires either a volatile toxicant applied very frequently or a residual one on the trees where the moths rest. The eggs are exposed for four days or more on the foliage and fruit but only a limited range of insecticides is effective against them. The newly hatched larva, despite its short free life, has generally been the stage against which insecticides are applied, either 44 | residual contact ones acting on the larvae crawling over the leaves and - fruit, or stomach insecticides acting on larvae as they penetrate the fruit. As with most other insects the larvae are most susceptible to insecticides when newly hatched. Smith (1926) and Heriot (1943) showed that even a stomach insecticide like lead arsenate may be toxic to crawling larvae and that the latter’s habit of discarding the epidermis of the apple does not entirely protect it from this insecticide. Some insecticides such as the organophosphates kill some larvae in the fruit (Hough, 1962) ; this effect may be important in reducing injury from the following brood. In the Niagara Peninsula the first-brood larvae may start to hatch within a week after the calyces close on the fruit and continue for nearly two months. The second brood often overlaps the first and may continue to hatch into September. Bait traps have been widely used in the United States for timing spray application but Garlick (unpubl.) showed they were unreliable in the Niagara district. By making daily counts of new larval entries in an unsprayed orchard where he also operated bait traps he found that the rate of entry was remarkably uniform throughout the season and showed little agreement with the fluctuations of moth catches in the traps. Entries also continued during the interval between spring- and first-brood flights in years when these did not overlap. However, in well-sprayed orchards there is usually an appreciable gap between the attacks of the two broods (Dustan, personal communication). An obser- vant grower could therefore wait for the first sign of second-brood attack before applying the later sprays if they were necessary. The usual practice, however, is to continue spray applications at regular intervals through the early part of second brood attack. Complete control of the first brood will obviously eliminate the second but this ideal is practically never attained. History of Insecticidal Control In 1878 a New York grower discovered that spraying apple trees with paris green to control the spring cankerworm, Paleacrita vernata (Peck), also gave considerable control of the codling moth (Woodward, 1879). This was soon confirmed by others in the United States, and about 1881 paris green was used in Ontario with very promising results (Saunders, 1884). At first only one application, soon after petal-fall, was believed necessary but comment in the Annual Reports of the Entomological Society of Ontario during the 1880’s indicated that this schedule did not give con- sistent control in the southern districts. By 1895 an additional application was recommended 10 to 15 days after the first (Caesar, 1948). Acid lead arsenate began to replace paris green in the United States early in the present century because of its greater persistence, lower phytoxicity, and compatability with lime sulphur. About 1908 it was tested in Ontario and soon became the standard insecticide for codling moth control (Caesar, 1948). The cheaper calcium arsenate came to be used to a limited extent but was more phytotoxic and less effective against the moth than lead arsenate. Even as late as 1934 a petal-fall (“calyx”) spray of lead arsenate gave good control in northern areas of Ontario and two sprays were suf- ficient a little farther south (Ross, 1934). In the warmest districts, how- ever, even three or more applications of lead arsenate could not prevent serious loss in some orchards. In the Niagara Peninsula many apple orchards were removed during the ’30’s because the loss from codling moth injury made them unprofitable. This decline in the effectiveness of lead 45 arsenate appeared during the previous 10 or 15 years in most of the warmer apple-growing districts of North America and stimulated a tremendous amount of effort on codling moth control. The Vineland and Simcoe labora- tories did much original work besides testing most control methods sug- gested elsewhere. Very little of this was formally published but the results in processed form were distributed annually as part of the pool of informa- tion to which all North American codling moth workers contributed. One line of research attempted to increase the efficiency of lead arsenate by more frequent and more thorough application and by the use of other agents to increase the deposit. This culminated in the “dynamite” or inverted spray mixtures (Marshall, 1937; Marshall and Groves, 1938), in which lead arsenate was preferentially wetted with oil so that very heavy deposits built up on the fruit. The natural consequence was dangerously high levels of arsenic and lead residues on the fruit, which had to be removed by washing in dilute acid or alkali. Fortunately this expensive process never became necessary in Ontario because no more than four “cover” (post-calyx) sprays of lead arsenate were applied and the “dynamite” mixtures were not used. Another approach was to increase the palatability of lead arsenate and other insecticides to the larvae by the addition of sugar (Siegler, 1940; Siegler and Jones, 1942; Wingo and Brown, 1942) ; at Vineland Station this mixture was phytotoxic (Patterson, unpubl.). A great range of candidate compounds was screened as possible substitutes for lead arsenate, especially in the United States; only those eventually used by growers can be mentioned here. Cryolite was the best of the inorganic compounds and was recommended for a few years in Ontario for the last (fifth) cover spray. Light, highly refined petroleum oil was a very effective ovicide besides helping to retain other insecticides on the fruit; it was used in many heavily infested Ontario orchards from 1940 onward in combination with lead arsenate and “fixed” nicotine. “Fixed’’ nicotine (nicotine alkaloid adsorbed on bentonite to give a persis- tent, residual insecticide) with oil emulsion was generally used as the last cover spray in problem orchards in Ontario after 1940. The first synthetic - organic insecticide to be used on a considerable scale against the moth, though not in Ontario, was phenothiazine. In August, 1948, the first samples of DDT were received at Vineland Station. They were immediately subject to intensive study in the laboratory (Dustan and Putman, 1947; Dustan et al. 1947; Putman, 1949) and in 1944 some rather crude formulations were tested against the codling moth in the field with outstanding results. Experimentation with different formu- lations in the laboratory and various spray schedules in the orchard was continued and as soon as consistently uniform and effective formulations became available in 1948 DDT was recommended in the Ontario spray calendar. In this first schedule three applications of DDT alternated with two of lead arsenate and oil emulsion. Although this schedule was economi- cal and highly effective against the codling moth and nearly all other apple pests it never became pepular with growers who disliked preparing the oil emulsion and who also objected to the duller fruit finish imparted by the oil. Eventually a schedule of DDT alone was recommended, lead arsenate being added to some of the cover sprays for apple maggot control. Parathion, the first of the persistent organophosphates, is very effec- tive against the codling moth, killing some larvae soon after they enter the fruit, but early applications are phytotoxic to some apple varieties and it was never used primarily for codling moth control in Ontario. Some newer 46 organophosphates such as diazinon and especially Guthion (Fisher, 1960) are very effective. The carbamate Sevin also gives excellent control of the moth but early-season applications cause fruit drop (Burts and Kelly, 1960; Batger and Westwood, 1960). Guthion and Sevin are now (1963) recom- mended for use in Ontario orchards with DDT-resistant strains of the moth. The botanical insecticide ryania attracted considerable attention because it is a more or less selective insecticide usually effective against the codling moth but having little effect on parasites and predators (Patterson and MacLellan, 1955; Clancy and McAlister, 1956; Pickett et al., 1958). In the first trial in Ontario it gave good control (Patterson and McClellan, 1955), but failed in a second (Fisher, 1960). In British Columbia ryania not only gave inferior codling moth control but also affected fruit quality and reduced yield the following year (Morgan and Anderson, 1957; Porritt, 1957). Resistance to Insecticides The codling moth was one of the ripet insects to develop resistance to an insecticide to which it was formerly susceptible. The increasing dif- ficulty of controlling it with lead arsenate in some parts of the United States inspired comparative laboratory tests of the ability of larvae from different areas to enter sprayed apples. Larvae from Colorado entered in much greater numbers than those from Virginia or Washington. Strains of larvae from commercial orchards in Virginia also entered more readily than those from isolated home orchards that had never been sprayed with lead arsenate. Strains selected by rearing larvae from the unsprayed orchards on sprayed apples for one to three generations eventually entered sprayed fruit more readily than the original unselected strains. Strains resistant to lead arsenate were also more resistant to a number of other insecticides. It was concluded that the resistance was due to greater vigour (“vigour tolerance” in modern terminology) rather than to true physiological resistance to the toxicant (Hough, 1929, 1934a, 1943). These conclusions were supported by Haseman and Meffert’s (1933) demonstra- tion that larvae of both resistant and non-resistant strains were equally susceptible to arsenicals injected into the haemocoel or gut. Steiner et al., (1944), however, concluded that differences in behaviour accounted for differing ability to enter lead arsenate - sprayed apples between larvae from two orchards in Ohio. The more “resistant” strain spent less time in crawling over the fruit and in attempting entrance. With the recent failure of lead arsenate fresh in mind it was no wonder that such codling moth authorities as W. G. Garlick and the late W. A. Ross greeted the spectacular efficiency of DDT with the remark “‘How long will it last ?”” Resistance of the codling moth to DDT first appeared about 1952 in Australia (Smith, 1955) and the United States (Cutright, 1954; Hamilton, 1956) and is now widespread in the latter country. In Ontario it appeared in 1957 in one orchard at Vineland Station; a high degree of resistance was confirmed by laboratory tests in 1959 (Fisher, 1960). In 1962 DDT resistance in Ontario was still confined to this and a few nearby orchards, and probably to an orchard near Trenton where DDT gave poor control during the previous two years (Dustan, personal communication). In British Columbia resistance appeared in 1958 (Marshall, 1959). ‘Measures Against Mature Larvae One of the earliest control measures applied against the codling moth was ropes of straw or hay tied about the trunks to trap maturing larvae. AT When arsenical sprays began to fail interest in trapping was renewed. At first, burlap or corrugated cardboard bands abcut the trunks were employed but these had to be removed and the larvae destroyed frequently to prevent emergence of adults. The development of bands treated with betanaphthol, which killed the larvae and which did not need to be renewed during the season, was a considerable advance (see Baker, 1943, for earlier refer- ences). Baker (1944) summarized previous estimates of the proportion of larvae trapped in bands; these ranged from 10 to 97 per cent of the larvae that left the fruit. Whereas some of this variation was undoubtedly real and due to differences in the availability of other cocooning sites, in other cases the method of calculation was likely faulty. Garlick’s (unpubl.) discovery that many more larvae may be trapped in bands than would normally winter on the trees was mentioned previously. If this is generally true the usual method of calculating the efficiency of bands from the numbers of trapped larvae greatly exaggerates their value in reducing the overwintering population. Garlick (unpubl.) used both untreated and chemically treated bands at Vineland Station and concluded that they were not efficient enough to justify the cost. . Another approach was direct spraying of the tree trunks with ma- terials that killed the larvae in situ. Ross et al. (1929) and others tested a range of materials such as pine tar oils and coal tar distillation products but for various reasons none were extensively used. Gnadinger et al. (1940) reported pyrethrins in oil to be very effective. Heriot’s (1942) report that oil sclutions of 3,5-nitro-o-cresol killed larvae in cocoons in the bark led to extensive investigations in British Columbia, Ontario, and the United States. It was soon found that straight oil solutions of dinitrocresol were too hazardous; at Vineland Station many trees were killed and the others badly injured in an orchard where the trunks and larger limbs were sprayed (Garlick, unpubl.). However, a concentrated aqueous emulsion of an oil-dinitrocresol solution and a wetting agent was very effective (Yothers and Carlson, 1945). At Vineland Station an extensive study of solutions and emulsions of dinitrocresol and other - toxicants was carried out in the laboratory and some orchard tests with dinitrocresol-oil emulsions were also conducted (Putman, unpubl.). Results were not promising and all work on trunk sprays was abandoned after DDT was introduced, perhaps fortunately because the high human toxicity of dinitrocresol solutions was not appreciated at that time. DDT in dry form was practically non-toxic to mature codling moth larvae. Yothers (1948) reviewed previous work on sprays to destrey overwintering larvae. More recently, Hamilton and Fahey (1958) showed that larvae were killed when they attempted to spin up in apple bark sprayed with some organophosphates. Ginsberg (1933) tested fumigants on diapausing larvae in the labora- tory ; hydrogen cyanide and ethylene chlorohydrin were most effective. No records of orchard trials have been found. Insecticides Against Adults Karly tests of nicotine vapour or sprays (e.g., Smith et al. 1934; Hough, 1934) and pyrethrum dust (Gnadinger et al. 1940) against the adult moths did not lead to practical application. Dennys (1942) reported that soluble salts of 3,5-dinitro-o-cresol were toxic to adults and gave promising results in early orchard trials in British Columbia. The advent of DDT made further work unnecessary, and the mammalian toxicity hazard from dinitro-cresol would prevent its use in any case. 48 It is likely that most of the synthetic contact larvicides are also toxic to adults. This has been shown by various workers (e.g., Hikichi, 1956; Garlick and Putman, unpubl.) to be true for DDT and others have demon- strated it for parathion. The true value of this effect in reducing fruit injury is unknown but may be appreciable. Other Measures Against Adults The ease of trapping the moths with fermenting solutions and other attractants naturally led to trials of this method for control. Although traps were reported by some authors, such as Yothers (1927) and Bobb et al. (1939), to reduce infestations to some extent they were not generally used for this purpose. Destroying the moths by light traps also reduced injury but the cost was far too great (Marshall and Hienton, 1935; Herms, 1947; Patterson, 1937). Attempts to reduce oviposition by illuminating the orchards were partly successful but not economical (Herms, 1947). Orchard Sanitation During the 1930’s the importance of orchard sanitation in codling moth control was stressed, particularly scraping the trees to remove rough bark, careful pruning to avoid splintered stubs, filling of cavities, and maintenance of a clean orchard floor, to reduce the number of sites for cocoons. With the cooperation of a local manufacturer of spray equipment a high-pressure jet of water was tried for removal of rough bark but. it required too much water to be practical (Putman, unpubl.). Since very efficient larvicides for the protection of the fruit are now available, such other measures do not seem economically justified. It is still advisable to store harvesting boxes in tight buildings and to keep these and packing sheds closed till late August to protect the orchards from moths which usually emerge late in such buildings. Artificial Use of Biotic Agents Under this heading is included the regular release or application of reared or cultured organisms for controlling the moth. This pest was among several against which mass releases of Trichogramma spp. were made (Flanders, 1930; Webb and Alden, 1940) but no appreciable reduc- tion in fruit injury followed and the method was abandoned in North America. It is still pursued in Russia where a number of species or races of Trichogramma differ in effectiveness against the codling moth (Meier, 1941; Kovaleva, 1957). These and other papers, however, do not indicate that Trichogramma produces a degree of control approaching that de- manded in America. Jaynes and Marucci (1947) were able to increase the incidence of the fungus Beauveria bassiana by using cultured spores, but the extent of infection of larvae was dependent on moisture and the use of this pathogen was not pursued further. Artificial dissemination of spores of Bacillus cereus originally isolated from the codling moth failed to control it (Phillips et al. 1953; Stephens, 1957). Spores of B. thuringiensis Berliner gave poor control of the moth (Madsen and Hoyt, 1958; McEwen et al. 1960), probably because the larvae are exposed for a much shorter time than are leaf-feeding lepidopterous larvae. Integrated Control A general increase in the destructiveness of orchard pests despite increase in amounts and kinds of pesticides applied for their control was A9 apparent for many years. This trend was especially intensified after the introduction of the very potent, wide-spectrum organic insecticides. It was theorized, and later proved in some cases, that the pesticides had upset biological balance, to use a much-criticized but still useful term, by destroy- ing parasites and predators. Consequently the balance might be restored by using pesticides with more specific action and restricting their application as much as possible. Entomologists in Nova Scotia have had outstanding success in this development of integrated or harmonized control of orchard pests. The codling moth can be controlled satisfactorily in Nova Scotia with two or three applications of ryania and in some orchards without any insecticides (Pickett et al. 1958; Pickett, 1959). LeRoux (1960) obtained good results in Quebec from a schedule based on the same principle. A similar approach to orchard pest problems is also being followed in England (Massee, 1958). These successes were achieved in areas where climate limited the biotic potential of the moth. In British Columbia integrated control could not be attained (Marshall and Morgan, 1956). Garlick (unpubl.) found that indigenous biological control factors in the Niagara Peninsula were quite unable to prevent very serious injury from the codling moth, a fact apparent from its previous history in this district. He also found that re- peated applications of ryania during a season had drastic effects on some biological agents: the predacious mirid Hyaliodes vitripennis (Say) was eliminated and parasitism by Trichogramma sp. and A. quadridentata was greatly reduced. Reduced parasitism may have been caused by the great reduction in host density, but whatever its cause it showed that chemical and biological control are not always additive. | Clancy and McAllister (1956) reported good results from sprays of ryania in West Virginia but these do not seem to have led to integrated control in that region. Where several applications per year are required ryania is probably too expensive for present use and would likely become still more so if the demand increased greatly, for the supply of ryania wood is limited. Use of Sterile Males The most recent approach to codling moth control is the release of sterile males. The use of heat as the sterilizing agent was unsuccessful (Proverbs and Newton, 1962) but irradiation with gamma rays gave prom- ising results in laboratory and cage experiments (Proverbs, 1962; Proverbs and Newton, 1962a, 1962b, 1962c). Large-scale orchard trials are awaited with great interest. Further Investigation Despite the extent of research outlined in this review, there are still considerable gaps in our knowledge of the codling moth. Some of these were pointed out on previous pages. The reproductive potential of the moth is uncertain, though it is difficult to see how it could be determined more precisely. As captive moths do not mate freely, study of the ecological conditions necessary for copulation might be fruitful. The dispersive ability of the adults needs further study. Dispersion seems to be rather limited within an orchard, where the moths are probably held by odours from the host trees, but nothing is known of the flight range of moths emerging in other locations to which they must often be transported as larvae. Such information is essential for attempts at local eradication, 50 The various effects of temperature on the codling moth have been extensively studied but little is known about the effect of rain on ovipo- sition, establishment of larvae, or other activity. A minor subject is nutrition of the adults. Do they obtain any nutri- ment, such as aphid honey-dew, in the orchards that increases fecundity ? A virtually untouched field is the population dynamics of the moth. It is true that most aspects have received some study, but independently and under diverse conditions. The relative importance of the various biotic and abiotic factors on the population density of the moth in any one locality is therefore unknown. The sampling problems might be formidable and such an investigation could be undertaken only if adequate support was certain. Breeding of apple varieties for resistance to the codling moth would be a long-term project indeed, and no cultivated variety seems to offer a source of high resistance that could be used as breeding stock. One approach is identification of the olfactory or gustatory stimulants that induce oviposition by moths and fruit penetration by larvae. However, these may be the same compounds that give apples their characteristic flavour. If the male-attracting pheromone secreted by the female could be chemically identified and synthesized, it might be useful for detecting very low infestations, or even for preventing copulation by saturating the environment. 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The course of certain processes in the body of insects at low temperatures. (In Russian). Doklady Akad. Nauk S.S.G.R. (N.S.) 68: 1101-1104. Abstr. in Rev. Appl. Entomology, A., 40: 94, 1952. USPENSKAYA, N. (1936). Causes of fluctuation in the number of codling moth popula- tion. (In Russian). In Summary of the scientific research work of the Institute of Plant Protection for the year 1935, pp. 277-280. Lenin Acad. Agr. Sci. U.S.S.R. Abstr. in Rev. Appl. Entomol., A., 25: 150, 1937. VAN LEEUWEN, E. R. (1929). Life history of the codling moth -in northern Georgia. U.S. Dept. Agr. Bull. 90. VAN LEEUWEN, E. R. (1940). The activity of adult codling moths as indicated by captures of marked moths. J. Econ. Entomol. 33: 162-166. : VAN LEEUWEN, E. R. (1943). Chemotropic tests of materials added to standard codling moth bait. J. Econ. Entomol. 36: 480-434. d : VAN LEEUWEN, E. R. (1947). Increasing production of codling moth eggs in an ovi- position chamber. J. Econ. Entomol. 40: 744-745. VAN LEEUWEN, BE. R. (1948). Attractiveness of pine-tar oil in baits for codling moth control. J. Econ. Entomol. 4i: 345-351. : WALLEY, G. S. (1951). Notes on Phanerotoma tibialis (Hald.) and P. fasciata Prov., Bee ci piions of two new species (Hymenoptera: Braconidae). Can. Entomol. So: -308. WEsB, J. E. and ALDEN, C. H. (1940). Biological control of the codling moth and the oriental fruit moth. J. Econ. Entomol. 33: 431-435. . ; ee, R. L. (1935). Codling moth larvae and the weather. J. Econ. Entomol. 28: 56-960. WEepstTER, R. L. (1936). A ten year study of codling moth activity. Wash. State Coll. Agr. Exp. Sta. Bull. 340. WEBSTER, R L. (1937). The relation of codling moth to temperature and rainfall. Proc. Wash. State Hort. Assoc. 1936, 32: 1383-141. WEISMANN, R. (1935). Untersuchen tiber den weiblichen Genitalapparat, das Ei und die Embryonalentwicklung des Apfelwicklers Carpocapsa pomonella. Mitt. schweiz. entomol. Ges. 16: 370-377. WELCH, H. E. (1962). Nematodes as agents for insect control. Proc. Entomol. Soc. Ontario 92: 11-19. WELLHOUSE, W. H. (1920). Wild hawthorns as hosts of apple, pear and quince pests. J. Econ. Entomol. 13: 388-391. WILpBoLz, T. (1958). Uber die Orientierung des Apfelwicklers bei der Eiablage. Mitt. schweiz. entomol. Ges. 31: 25-34. WILpDBOLz, T. and BaAGGIOLINI, M. (1959). Uber das Mass der Ausbreitung des Apfel- wicklers wahrend der Fiablageperiode. Mitt. schweiz. entomol. Ges. 32: 241-257. WINGO, C. W. and Brown, H. E. (1942). Field studies of codling moth larvae attrac- tants. J. Econ. Entomol. 35: 284-285. WoopsipE, A. M. (1941). Studies of codling moth cocooning habits. J. Econ. Entomol. 84: 420-424. WoopsipE, A. M. (1944). Codling moth infestation at different heights in apple trees. Virginia Agr. Expt. Sta. Bull. 360. 5 WOODWARD, J. S. (1879). Paris green and sheep versus the codling moth. Rural New Yorker 38: 87. Cited by Slingerland (1898). WorTHLEY, H. N. (1932). Studies of codling moth flight. J. Econ. Entomol. 25: 559-565. WorTHLEY, H. N. and NICHOLAS, J. E. (1937). Tests with bait and light to trap codling moth. J. Econ. Entomol. 30: 417-422. WYNIGER, R. (1956). Uber die Wirkung von abiotischen Faktoren auf die Enwick- lungsvorgange in Apfelwicklerei. Mitt. schweiz. entomol. Ges. 29: 41-57. YoTHERS, M. A. (1927). Summary of three years’ tests of trap baits for capturing the codling moth. J. Econ. Entomol. 20: 567-575. YoTHErRS, M. A. (1928). Are codling moths attracted to lights? J. Econ. Entomol. 217: 836-842. YotuHeErsS, M. A. (1948). A review of the literature on sprays to destroy overwintering codling moth larvae. U.S. Dept. Agr. Bur. Entomol. Plant Quarantine, E-761. YoTHeErRS, M. A. and CARLSON, F. W. (1941). Orchard observations of the emergence of codling moths from two-year-old larvae. J. Econ. Entomol. 34: 109-110. YoTHERS, M. A. and CARLSON, F. W. (1945). Three years of orchard tests of 4,6-dinitro- o-cresol against overwintering codling moth larvae. J. Econ. Entomol. 38: 723-724. YoTHERS, M. A. and VAN LEEUWEN, E. R. (1931). Life history of the codling moth in the Rouge River Valley of Oregon. U.S. Dept. Agr. Tech. Bull. 255. (Accepted for publication: May 13, 1963) 59 i : { Fics. 1-4. Codling moth. 1. Adult moth, 1.3X. 2. Egg on apple, 10X. 3. External and internal injury to apple, and mature larva, 1X. 4. Cocoons beneath bark scale, 1.3X. 60 Biology of Cabbage Caterpillars in Eastern Ontario’ D. G. HARCOURT Entomology Research Institute otha Research Branch, Canada Department of Agriculture Ottawa, Ontario This review is based on relevant publications by the writer and others, as well as a considerable amount of unpublished data accumulated by the writer during the course of long-term investigations on dynamics and general biology of the species . In these studies, permanent field plots were laid out in 1951 at the Merivale field station, five miles south of the Central Experimental Farm, Ottawa. Although intensive studies were confined to the Merivale locality, extensive observations have been made throughout eastern Ontario during the past twelve years. A complex of species of Lepidoptera attack crucifers in eastern Ortario. The most important of these is the imported cabbageworm, Pieris rapae (L.), which causes considerable economic damage each year. The diamondback moth, Plutella macuitpennis (Curt.), often underrated because of its small size, has been extremely numerous and locally impor- tant during the past decade. The cabbage looper, Trichoplusia nt (Hbn.), is a sporadic pest, but is not sufficiently abundant in most years to consti- tute a commercial problem. There are, in addition, five minor lepidopterous pests of crucifers, not all of which are continually present in eastern Ontario. The eight species are dealt with in decreasing order of importance. THE IMPORTED CABBAGEWORM History and Distribution The imported cabbageworm was first discovered in North America in 1860 when a single adult specimen was captured at Quebec by William Couper (Bowles, 1864; Ritchie, 1869). By 1863 the insect had become sufficiently abundant to cause severe economic damage within a forty-mile radius of Quebec. By 1865 it had spread into the State of Maine (Scudder, 1887) and in the following year was taken in the northern parts of New Hampshire and Vermont (Minot, 1869). By 1867 it had extended as far east as Halifax, Nova Scotia (Jones, 1874), and in 1869 it was taken in Massachusetts and New Jersey (Mead, 1870; Minot, 1869). The insect was first discovered in Ontario by Bethune (1872) who reported it from the eastern part of the Province in 1871. By 1872 it had reached the western end of Lake Ontario (Bethune, 1873; Brodie, 1875), and by 1876 it occupied the whole of southwestern Ontario (Saunders, 1876). By 1886 it had spread as far south as the Gulf of Mexico, as far north as Hudson’s Bay, and west to the Rocky Mountains (Scudder, 1887). It now occurs throughout most of North America. Taxonomic History The imported cabbageworm was first described by Linnaeus (1758) as Papilio rapae. Esper (1777) listed it as Papilio Danaus rapae, using Danaus as a subdivision of Papilio. The genus Pieris was erected by Schrank (1801) and he included rapae in this genus. Since that time it has been variously placed in a number of genera, including Pontia Fabr., Ganoris Dalm., and Synchloe Hbn. tPrepared at the invitation of the Publications Committee, Entomological Society of Ontario. Proc. Entomol. Soc. Ont. 93 (1962) 1963 61 General Descriptions of the Stages Lgg The egg (Fig. 1) is shaped like a short, thick bullet having its greatest diameter about one-third of the distance from the apex. There are 12 longitudinal keels running the length of the chorion; these are linked by a series of transverse ribs. When first laid, the egg is pale white but it darkens with embryonal development and is a straw yellow just before Fics. 1-6. The imported cabbageworm. 1, Egg on a portion of leaf. 2, Feeding damage to head and wrapper leaves of cabbage. 3, Larvae. 4, Pupa, lateral aspect. 5, Adult male, dorsal aspect. 6, Adult female, dorsal aspect. 62 hatching. The egg is about 1 mm. in length, 0.5 mm. in diameter, and it stands erect, being attached to the leaf at its basal end. Larva The caterpillar (Fig. 3) is cylindrical in shape with five pairs of fleshy prolegs. The head and body are pale green, the latter having a solid lemon- coloured stripe down the m.d dorsal surface and a broken lateral band of the same colour formed by pairs of elongated spots near each spiracle. The larva has a velvety appearance due to a profusion of black and white hairs that form a white bloom over the body. The relative sizes of the five larval instars are as follows: Instar Head capsule width Body length, end of instar 1 0.88 mm. 3.2 mm. 2 0.60 mm. 8.8 mm. 3 0.96 mm. 14.0 mm. 4 1.49 mm. 20.2 mm. 5 ZEB Sanne 30.1 mm. Pupa The chrysalid (Fig. 4) is pale green to speckled brown, the colour usualiy harmonizing with its surround:ngs. The head is beaked in front and the thorax strongly angulated by a central dorsal keel that rises acutely at the middle and declines to the abdomen; it then again rises gently and curves to the anal segment, terminating in a long cremaster furnished with hooks. It measures 18 mm. in length. Adult The butterfly (Figs. 5 and 6) has been described by many authors. Frohawk (1914) gives the following: “Male: Glaucous-white, apex of fore wing grey or blackish, a single black spot near the middle, and a black spot on the costa of the hind wing; base of all the wings powdered with black and grey scales, and grey along costa of fore wing. Female: Creamy-white to yellow-buff; grey or black tip to fore wing; two black spots, one as in the male, the other near and sometimes united to the club-shaped dash along the inner margin; hind wing with black costal spot. Base of all wings suffused with grey and black, mostly on fore wings, which frequently have the basal half dusted all over.” “Head and front of thorax ochreous, rest of thorax and abdomen clothed with grey hairs. Antennae with extreme apex ochreous.” _ The average wing expanse is 50 mm., the female being slightly larger in size than the male. Closely Related Species McDunnough (1958) in his catalogue of North American Lepidoptera lists eight species under the genus Pieris. Of these, only P. rapae, P. protodice Bdv. & LeC., P. napi (L.), and P. virginiensis Edw. have been recorded from Ontario. Life History and Habits The following is based on reports by Moss (1933), Richards (1940), Muggeridge (1943) and Twinn (1924) as well as unpublished data of the writer. The eggs are laid singly, as a rule on the outer leaves of the plant. Roughly 70 per cent of them are deposited on the lower leaf epidermis, 63 close to the leaf veins. In hatching, the larva tears an opening in the chorion near the apex of the shell and emerges head foremost. In eastern Ontario, the incubation period varies from four to eight days, averaging five during July and August. The newly-hatched larva immediately devours the chorion, often consuming a few leaf tissues and creating a shallow depression on the leaf where the egg had rested. The larvae feed from the lower leaf surface, remaining on the outer leaves of the plant until just previous to the third moult. At this time they move to the central part of the plant to feed on the edible portions of the crop. Most damage is done to the plants in the final two instars. At this time the larvae feed voraciously, chewing large irregular holes in the wrapper leaves of cabbage and eating into the outer layers of the head itself (Fig. 2). They deposit masses of greenish to brown excrement that stain the heads of cauliflower and broccoli, lessening their market value. The larval period varies from 12 to 33 days, averaging 15 during July and August. Most authors report that the mature larvae migrate in search of suitable pupation sites, transformation taking place on objects in or near the field, such as outbuildings, packing cases, or fence posts. At Merivale, the chrysalids were usually found on the host plant, on the under surface of the lower or ground leaves. Migration of larvae appears to be a density- dependent phenomenon. In pupating, the larva spins a pad of silk to which it attaches its caudal end, then passes a loop of silk around its body in the region of the thorax to keep from hanging head downward. After moulting, the characteristic thoracic and abdominal projections appear. The com- bined duration of the pupal and prepupal stages varies from eight to 20 days, averaging 11 during July and August. The butterflies are active during most of the daylight hours. They alternately feed and oviposit for brief periods, moving to and from the blooms of wild plants in the immediate vicinity of the crop. Thus they tend to lay more eggs in the border rows of the crop than in those nearer the centre. Flight is irregular and slow except when the butterflies are being carried by the wind. To stabilize flight during windy periods of the day, ovipositing females move across the field against the wind, laying their eggs on the leeward side of the plants (Harcourt, 1961a). Mating and oviposition occur within 24 hours of emergence. While in copula, the male flits awkwardly from plant to plant, the female remaining passive with wings folded. In oviposition, the female lands on the edge of a leaf and curves her abdomen downward until the tip of her ovipositor touches the lower surface. At the moment of impact a single egg is glued to the leaf. According to a number of authors the female lays upwards of 300 eges, although studies by the writer indicate a somewhat lower figure. The life span of the adult is approximately three weeks (Norris, 1935). Seasonal History There are three generations a year in eastern Ontario, the winter being passed as a chysalid in or near the overwintered crop. The adults emerge from mid to late May and lay eggs during the next two weeks. Egg-laying of the second generation reaches its peak during the second week of July, and that of the third generation at mid August. The period required for a complete generation, egg to adult, varies from 24 to 61 days, averaging 31 in July and August. Although density of the first generation 64 is largely attributable to overwintered pupae, abundance in succeeding generations is frequently affected by invasion of butterflies from more southerly regions. sea Flight Habits Studies at Merivale on the flight behaviour of P. rapae showed that the adult is on the wing for about 11 hours a day. Flight begins about two hours after sunrise and reaches its peak just before noon. Conditions most favourable for flight, copulation, and oviposition are high temperatures associated with low wind velocities and maximum radiation. On the other hand, low temperatures and high wind velocities limit activity. Contrary to a report by Stephen and Bird (1949) based on laboratory experiments, barometric pressure does not appear to determine the nature of flight activity. Host Relationships According to Twinn (1924), the insect attacks cultivated and wild plants belonging to four families, namely Cruciferae, Resedaceae, Cap- paridaceae, and Tropaeolaceae. The same author reported that cabbage was preferred among the cultivated plants. However, in an experiment by the writer on attractiveness of cultivated hosts, the insect attacked cabbage, cauliflower, Brussels sprouts and broccoli in equal numbers. In eastern Ontario, it is commonly found on the following cruciferous weeds: Thlaspi arvense L., Lepidium densiflorum Schrad., Capsella bursa-pastoris (L.) Medic., Brassica kaber (D.C.) L.C. Wheeler var. pinnatifida (Stokes) L.C. Wheeler, Brassica hirta Moench, Erysimum cheiranthoides L., Barbarea vulgaris R. Br., Corringia orientalis (L.) Dumort., and Nasturtium of- ficinale R. Br. var. microphyllum (Boenn.) Thell. Mortality Factors Natural Enemies. Six species of parasites have been recorded from P. rapae in eastern Ontario. The principal parasite causing death of larvae is the braconid Apanteles glomeratus (L.). The female attacks caterpillars _ in the first two instars, the fully-fed parasites emerging from the mature larva shortly after the host spins its pupal mat. A large but variable number of eggs is laid in each host. The tachinid Phryxe vulgaris (Fall.) attacks larvae in the later instars, attaching a single egg to the skin of the host. The larva hatches and burrows in, developing as an endoparasite. The fully-fed parasite emerges from the host pupa. The chalcidoid Pteromalus puparum (L.) attacks the pupae, ovipositing many times in a single chrysalid. The parasite develops within the host, emerging from an ir- regular number of exit holes cut in the region of the butterfly wing.. Of much less importance than the preceding three species are the polyphagous tachinid Compsilura concinnata (Mg.), the sarcophagid Helocobia rapax Wlk., and the tachinid Madremyia saundersii (Will.). The latter consti- tutes a new host record for the species (Thompson, 1951). It has pre- viously been recorded only from Pieris occidentalis Reak. (Aldrich and Webber, 1924). Invertebrate predators are of little importance in eastern Ontario. Predation of larvae by birds’ has been occasionally observed. a ae ae NO se RiP eno PEO SSE ORES oh PS UCU EOE a eT Sy SBC ein SAN Ses Se MS ee VS Ee a *Chiefly, the brown-headed cowbird, Molothrus ater (Boddaert), the song sparrow, Melospiza melodia (Wilson), and the redwing, Agelaius phoeniceus (L.). 65 __.The caterpillars are killed in large numbers by a highly virulent granulosis disease. In the early stages of infection, larvae are characterized by general sluggishness and a paler than normal body colour. As the infec- tion proceeds the body colour becomes milky-yellow and bloating is evident. After death, the body quickly blackens; the integument ultimately rup- tures and its liquified contents ooze out over the leaves. The symptoms — correspond to those given by Tanada (1953) for disease caused by Ber- goldia virulenta Tan. Mortalities due to the virus at Merivale have ranged as high as 94 per cent. Rainfall. Larvae are frequently drowned by rainfall during the first two instars. At this time they are small, and during periods of rainy weather they are often washed into the leaf bases. Some are forced to the ground where they quickly perish in pockets of surface water. Adult Mortality. During the adult period, numbers of P. rapae are reduced by predation, mating failure, and failure of females to lay their full complement of eggs as a result of inclement weather. In addition, some adult mortality may be attributed to wind transport of unspent females to non-agricultural areas where food plants and oviposition sites are minimal. Estimating Field Populations Harcourt (1962) reported on a sampling method for the immature stages of P. rapae. At moderate population densities, 20-70 plants will provide acceptable limits of precision in estimating population means for five age intervals. The spatial pattern of the insect conforms to the nega- tive binomial series (Harcourt, 1961la). THE DIAMONDBACK MOTH History and Distribution The diamondback moth is a cosmopolitan species, apparently origi- nating from the region of the Mediterranean Sea. It was first reported from North America by Fitch (1855) who observed it during the summer of 1854 in vegetable gardens near Ottawa, Illinois. Further records of the insect did not appear in the literature until 1870 when damage was reported from Massachusetts, Maryland, and Michigan. The following year, it was found in New York and New Jersey. By 1883, the insect had spread as far south as Florida and as far west as the Rocky Mountains (Riley, 1883). In 1885, it was reported from Western Canada (Fletcher, 1891), and in 1895 economic damage was observed for the first time in Ontario (Fletcher, 1896). It is now present in every province of Canada and ap- parently occurs throughout the United States. ; Taxonomic History The diamondback moth was first illustrated by Roesel (1746), who gave a short account of its habits. In the same year, it was described by Linnaeus (1746) and placed in the genus Phalaena. Linnaeus subsequently described it, in part, under the name Phalaena Tinea xylostella (1758; 1761; 1767). Unfortunately, he confused it here with the honeysuckle- feeding species Harpipteryx xylostella L. The proper separation of the species was made by Curtis (1832), who proposed the name maculipennis. Zeller (1843), overlooking Curtis’ work, restricted the names in a like manner and proposed for the crucifer- ous-feeding species the name cruciferarum. The latter name was used for many years, but it was finally pointed out by Walsingham and Durrant (1897) that Curtis had previously described it under the name maculipen- Nis. 66 Fics. 7-13. The diamondback moth. 7, Two eggs on a portion of leaf. 8, Pupa enclosed in cocoon, lateral aspect. 9, First-instar larva, dorsal aspect. 10, Fourth-instar larva, dorsal aspect. 11, Pupa, ventral aspect. 12, Female moth, dorsal aspect. 13, Male moth, dorsal aspect. 67 The genus Plutella was erected by Schrank (1802) for the single species xylostella L. which he cited to Roesel (1746) and Schiffermiller and Denis (1776). The name zylostella has subsequently been placed in the genus Harpipteryx Hbn. General Descriptions of the Stages Ligg The egg (Fig. 7) is oval and somewhat flattened, having a scale-like appearance on the leaf. It is pale green to lemon-yellow and the surface is embossed with a pattern of small, circular, raised areas. Shortly before hatching, the outline of the larva can be distinguished beneath the chorion. The average length is 0.44 mm. and the average width 0.26 mm. Larva The larva is subcylindrical and relatively hairless, with five pairs of prolegs. There are four instars. At the beginning of each stadium, the head is the same width as the body. As growth proceeds, the larva becomes decidedly spindle-shaped, the body being widest about the centre of the abdomen and tapering towards both ends. _ The body of the first-instar larva (Fig. 9) is almost entirely lacking in pigmentation. An irregular brown patch is present on each side of the mid-dorsal line of the phothoracic shield, and: a circle of light-brown pigment surrounds the base of each abdominal seta. Apart from this, the only traces of pigmentation are found on the legs. The head is dark brown. Although the later instars (Fig. 10) superficially resemble the first, a few differences can be readily noted under a hand lens. The prothoracic patches have been replaced by numerous brown spots, marking the setal bases. The head capsule is somewhat lighter, and mottled with dark brown pigment. Also, the pigmented areas surrounding the bases of the abdominal setae are more distinct, being larger and darker than in the first instar. Toward the end of the final instar the body often takes on a greenish hue due to accumulation of food particles in the gut. For a detailed description of the larvae, including setal maps, the reader is referred to Robertson (1939). The relative sizes for the four larval instars are as follows: Instar Head capsule width Body length, end of instar 1 .16 mm. 1.7 mamas 2 25 mm. 3.5 Mmm. 3 37 mm. 7.0 mm. 4 .61 mm. 11.2 namie There is no ecdysis between the last larval instar and the prepupa, the two differing only slightly in general appearance. The latter is more con- tracted in form, especially in the region of the head and thorax, and is pale green. Pupa The pupa (Fig. 11) is of the obtect type, characteristic of most Lepidoptera. The cephalic end is rounded, the body being widest in the thoracic region and tapering gradually toward the slender caudal segment. The mouth parts are clearly defined, and the mesothoracic wings are long, extending posteriorly to the caudal margin of the fifth abdominal seg- ment. When first formed it is pale green, but it gradually becomes light 68 fawn with brownish markings. It measures 7 mm. in length, and is enclosed in a neat, open-network, silken cocoon that is open at both ends (Fig. 8). Adult The adult (Figs. 12 and 13) has been frequently described by Lepidop- terists. It is a small, slender, greyish-brown moth with a wing expanse of slightly more than half an inch. At rest, the forewings lie close to the sides of the body, meeting above and, in profile, presenting a slightly upturned appearance at the posterior end; a creamy-yellow dorsal band extending from the base almost to the tornus, is separated from the rest of the disc by an irregular border of black that has three distinct undulations. The hind wings are dark grey. Although rather distinct colour variations occur, the colours of the female are typically lighter, and the markings less distinct than those of the male. Closely Related Species Twenty-six species are listed in Lepidopterorum Catalogus (Meyrick, 1914) under the genus Plutella, all of which feed on the leaves and flowers of Cruciferae. Although 10 of these occur in North America (McDunnough, 1939), only P. maculipenms and P. porrectella (L.) have been recorded from Ontario. Life History and Habits Harcourt (1957) studied the life history and habits of the insect. The eggs are laid singly or in small groups (two to eight), mainly on the upper surface of the leaf. Just before hatching, the egg darkens and the young larva can be seen coiled within the chorion. The larva gnaws a circular opening through one end of the chorion and emerges head foremost. The incubation period varies from four to eight days, averaging five during July and August. The newly-hatched larva crawls to the lower surface of the leaf and bores through the epidermis. During the first instar it mines the leaf tissues, feeding in the spongy mesophyll. At the end of the first instar it emerges from the mine, spins a few protective threads and moults beneath, selecting a sheltered site such as a depression on the leaf or near an edge that is slightly curled. It does not mine the leaf tissues after the first instar, although larvae in all but the final stadium frequently feed with head and thorax buried in the leaf. The older larva usually feeds from the lower surface, chewing irregular patches in the leaves. All the leaf tissues are consumed except the veins and the upper epidermis. This causes a windowing effect that is distinctive of the species. Most injury is done to the plants in the final instar. In addition to feeding on the leaves, the larvae may then attack other parts of the plant. Mature larvae often feed on the florets of cauliflower and broccoli, and bore into the edible portions of cabbage and Brussels sprouts. The larval period varies from nine to 30 days, averaging 12 during July and August. The mature larva constructs its cocoon on the host plant, typically on the lower leaves, but not infrequently on the wrapper leaves of cabbage, or amongst the florets of cauliflower and broccoli. Spinning of the cocoon is followed by one to two days of quiescence that mark the prepual stage. The cast skin remains within the cocoon at the caudal end of the pupa. The combined duration of the prepual and alc stages varies from five to 15 days, averaging eight in July and ugust. 69 The moths are inactive during the daytime and rest motionless on the lower surface of leaves of the host plant. They are weak fliers and are readily carried by the wind. On a windless evening their flight appears hesitant, the moths seldom rising more than five feet above the ground and typically travelling no more ihan 10 to 12 feet in a horizontal direction. They become active just before dusk when they move to the blossoms of cruciferous weeds to feed. Mating occurs at dusk on the day of emergence and lasts about one hour. Oviposition begins shortly after dusk and reaches its peak about two hours later, few eggs being laid after midnight. The female crawls slowly over the leaf surface and after probing momentarily with the tip of her ovipositor deposits a single egg. She may return to append additional eggs. The eggs are usually laid on the leaves, but occasionally if the plants are small, on the stems and petioles. Typically they are laid in depressions of the leaf along the midrib and larger veins, or on the concave surfaces of the smaller veins. Other favourite sites are yellow patches on the leaf and in feeding ‘windows’ of the larvae. The life span of the female averages 16 days, that of the male, 12. In study cages the number of eggs laid per female ranged from 18 to 356, with a mean of 159. Egg-laying lasted about 10 days, the peak occurring on the first night of oviposition, except when temperatures at sunset were below 66°F. Seasonal History There are four to six generations a year in eastern Ontario, depending upon seasonal temperatures. The period required for a complete generation varies from 18 to 51 days, averaging 25 in July and August. The insect does not overwinter in eastern Ontario. Annual infestations are attributable to adults that overwinter in more southerly regions and migrate north in the spring as the weather moderates. In most years the immigrants begin to arrive at the field station during the latter half of May. Ecology Flight Habits Light trap studies at Merivale have shown that the moth is active for an average of 136 days each year and that the heaviest period of flight is from late July to early September. The peak of flight in the night occurs during the hour beginning 90 minutes after sunset. Conditions most favourable to flight are high temperatures coupled with low wind velocities. On the other hand, low temperatures, high wind velocities, and rainfall limit activity. Host Relationships The moth attacks cultivated crops and wild plants of the family Cruciferae, as well as a number of cruciferous ornamentals including wallflower, candytuft, stocks, and allysum. At Merivale, equal numbers of the insect were found on cabbage, cauliflower, Brussels sprouts, and broccoli. Wild hosts play an important role in maintaining populations of the moth, particularly in years when adults begin to arrive from the south before the planting of cultivated crops. In eastern Ontario, it is commonly found on the following weeds: Thlaspi arvense L., Lepidiwm densiflorum Schrad., Capsella bursa-pastoris (L.) Medic., Brassica kaber (D.C.) L.C. Wheeler var. pinnatifida (Stokes) L. C. Wheeler, Brassica hirta Moench, 70 Erysimum cheiranthoides L., and Barbarea vulgaris R. Br. The latter, which blooms in the early spring, appears to be a favoured host. Mortality Factors Natural Enemies. The role of major mortality factors in the dynamics of the insect has been discussed in a recent paper (Harcourt, 1963). Ten parasites have been recorded from P. maculipennis in eastern Ontario. The most important of these is the ichneumonid Horogenes insularis (Cress.), which causes an average mortality of 33 per cent. The female attacks larvae in the first three instars, the fully-fed parasite emerging from the prepupa shortly after the host has spun its cocoon. The ichneumonid Diadromus plutellae (Ashm.) attacks the prepupae and newly-formed pupae, causing an average mortality of 21 per cent. The braconid Microplitis plutellae (Meus.) destroys about 10 per cent of all host larvae during the final instar. Of lesser significance are the eulophid Tetrastichus sokolowsku Kurdj., the chaleid Spilochalcis albifrons (Walsh), the ichneumonids Gelis tenellus (Say) and Campoletis sp., and the pteromalids Dibrachys cavus (Wlkr.), Habrocytus sp., near phycidis Ashm. and Eupteromalus viridescens (Walsh), the last being a parasite of H. insularis. Invertebrate predators are of little importance in eastern Ontario, although spiders, mites, Chrysopidae, Pentatomidae, and Miridae have occasionally been observed to attack the larvae. Birds are sometimes important late in the season when roving flocks of the redwing descend upon the plants to feed on larvae and cocoons. Deaths due to disease are negligible. Rainfall. The larvae are very susceptible to drowning during periods of rainy weather. Rainfall readily disturbs the small caterpillars and they are washed or wriggle from the plants intc puddles on the ground, or into leaf axils containing water. More than half of all larvae in the first three -instars perish this way. Adult Mortality. The adult period is the most critical stage in the population dynamics of the species. Considerable mortality results from the failure of gravid females to lay their full complement of eggs. The moths rarely fly during cool or windy weather, and any prolonged period of inclement conditions during the adult stage reduces activity, resulting in death of many females before oviposition is completed. In addition, there is some dispersal of moths to non-agricultural areas due to convective activity in the early evening or turbulent wind transport, particularly at high densi- ties. Adult mortality at Merivale has averaged 72 per cent, at times ranging as high as 97 per cent. Estimating Field Populations Harcourt (1961b) reported on a sampling method for the immature stages of P. maculipennis. Except at low population densities, 40-150 plants will provide acceptable limits of precision in estimating population means for five age intervals. The distributional pattern of the insect con- forms to the negative bincminal series (Harcourt, 1960a). THE CABBAGE LOOPER This insect is not sufficiently abundant in most years to cause com- mercial damage in eastern Ontario. During the past decade, outbreaks have occurred only in 1955, when resistance to DDT was observed in the Ottawa Valley, (Harcourt, 1956), and in 1959. 71 The larva (Fig. 14) is similar in size to the imported cabbageworm. It is pale-green with a narrow white stripe along each side of the body just above the spiracles, and two others near the mid-dorsal line. The body tapers towards the head and has three pairs of slender legs near the head, and three pairs of thick prolegs near the posterior end. It crawls by doubling up to form a loop, then projecting the front end of the body for- ward. Hence, the common name. There are typically three generations a year in eastern Ontario, the winter being passed in the pupal stage. The cocoons are attached to the underside of the lower leaves of the host plant. The moths emerge during late May and deposit up to 200 eggs, singly, on either side of the leaves, as a rule near the margins. The larvae pass through five instars. The insect is a more general feeder than P. rapae or P. maculipennis. In addition to wild and cultivated plants of the cabbage family, it attacks a number of vegetables, including lettuce, celery, and spinach. Extensive injury to the latter three crops has been observed in parts of central and southwestern Ontario during the past four years. In eastern Ontario, the species confines its damage to cabbage and cauliflower. SSS a SEES Seoee Fics. 14-15. The cabbage looper. 14, Mature larva on leaf of cabbage. 15, Mature larva killed by polyhedral virus disease. Natural Hnemies Four species of parasites have been recorded from T. ni at Merivale. The most important of these is the polyembryonic encyrtid Copidosoma truncatellum (Dalm.), which lays its egg within that of the host. The parasite develops within the host caterpillar, killing it shortly after it has spun its cocoon. The writer has reared as many as 1124 specimens from a single larva. Less important parasites are the polyphagous ichneumonid Itoplectis conquisitor (Say), the tachinid Compsilura concinnata (Mg.), and the ichneumonid Stenichneumon culpator cincticornis (Cress.). 12 Field populations of the cabbage looper are frequently destroyed by a polyhedral virus disease of the larvae. Infected individuals cease to feed and crawl to the outer leaves of the plant to die. The body colour quickly transforms from a shiny green to a dull yellow, and after death to a grey-black. Dead larvae characteristically hang from the leaves, attached only by the prolegs (Fig. 15). Presence of the virus was first noted in eastern Ontario in 1959 (Harcourt, 1960b). LEPIDOPTERA OF MINOR IMPORTANCE Five species of Lepidoptera may be listed as minor pests of crucifers in eastern Ontario. Taken in decreasing order of abundance at Merivale were the following: the zebra caterpillar, Ceramica picta (Harr.), the clover cutworm, Scotogramma trifolii (Rott.), the red-banded leaf roller, Argyrotaema velutinana (Walk.), the salt-marsh caterpillar, H’stigmene acrea (Drury), and the armyworm, Pseudaletia unipuncta (Haw.). PROBLEMS OF CONTROL IN EASTERN ONTARIO In eastern Ontario, cabbage and cauliflower are transplanted from the seedbed to the field in two periods. The early crop, which matures in July, is planted in late May; the late crop, which matures in October, is planted in late June. The early crop frequently escapes serious feeding injury by caterpillars, and in most years, does not require an insecticide if harvested by the middle of July. If it is harvested during late July a single application of a short residual insecticide is required to control larvae of the imported cabbageworm and the diamondback moth, which increase rapidly in numbers at this time. Populations of the cabbage looper are negligible on the early crop. _ Caterpillars of all three species attack the late crop. Late cabbage and cauliflower are attacked throughout the growing season, but the population of the species complex usually reaches its peak in August. The imported cabbageworm is present in greatest numbers during the latter half of July and August; the diamondback moth, in August and early September; and the cabbage looper, in late August or early September. The imported cabbageworm is the species largely responsible for damage to the late crop, and insecticide applications are primarily directed against it. Control recommendations are presently based on one or two pre-heading applications of a long residual insecticide, plus three or four applications of a less stable chemical after head formation (Ontario Depart- ment of Agriculture, 1963). Literature Cited AuLprRicH, J. M. and R. T. WEBBER (1924). The North American species of parasitic pecwineed sues belonging to the genus Phorocera and allied genera. Proc. U.S. Nat. us. 63: 1-90. BETHUNE, C. J. S. (1872). Insects affecting the cabbage. Ist Ann. Rep. noxious insects Prov. Ontario, pp. 422-428. BETHUNE, C. J. S. (1873). On some of our common insects. Canadian Ent. 5: 41-43. BowL.Les, G. J. (1864). On the occurrence of Pieris rapae in Canada. Canadian Nat. and Geol. (N.S.) 1: 258-262. 2 De (1875). The cabbae-worm (Pieris rapae) and its parasite. Canada Worm: 2: : CurTIS, J. (1832). British entomology. Vol. 9, plate 420. ESPER, E. J. C. (1777). Die Schmetterlinge in Ubbildungen nach der Nature mit Bischreibungen i: 55. Fitcu, A. (1855). First report on the noxious, beneficial and other insects of the State of New York, N.Y. State Agr. Soc. Albany. 73 FLETCHER, J. (1891). Report of the Entomologist and Botanist, 1890. Canada Dept. Agr., Ottawa. ; ; FLETCHER, J. (1896). Insect injuries of the year 1895. 26th Ann. Rep. Ent. Soc. Ontario, 1895: 32. BY FROHAWK, F. W. (1914). Natural history of British butterflies. Hutchinson and Co., London. Harcourt, D. G. (1956). Occurrence of a DDT-resistant strain of the cabbage looper, Trichoplusia ni (Hbn.), in the Ottawa Valley. Canadian J. Agric. Sci. 36: 430-434. Harcourt, D. G. (1957). Biology of the diamondback moth, Plutella maculipennis (Curt.) (Lepidoptera: Plutellidae), in eastern Ontario. II. Life history, behaviour, and host relationships. Canadian Ent. 89: 554-564. Harcourt, D. G. (1960a). Distribution of the immature stages of the diamondback moth, Plutella maculipennis (Curt.) (Lepidoptera: Plutellidae), on cabbage. Canadian Ent. 92: 517-521. Harcourt, D. G. (1960b). Note on a virus disease of the cabbage looper in the Ottawa Valley. Canadian J. Plant Sci. 40: 572-573. Harcourt, D. G. (1961a). Spatial pattern of the imported cabbageworm, Pieris rapae (L.) (Lepidoptera: Pieridae), on cultivated Cruciferae. Canadian Ent. 93: 945-952. Harcourt, D. G. (1961b). Design of a sampling plan for studies on the population dynamics of the diamondback moth, Plutella maculipennis (Curt.) (Lepidoptera: Plutellidae). Canadian Ent. 93: 820-831. Harcourt, D. G. (1962). Design of a sampling plan for studies on the population dynamics of the importea cabbageworm, Pieris rapae (L.) (Lepidoptera: Pieridae). Canadian Ent. 94: 849-859. Harcourt, D. G. (1963). Major mortality factors in the population dynamics of the diamondback moth, Plutella maculipennis (Curt.) (Lepidoptera: Plutellidae). Canadian Ent. Mem. 322. JONES, J. M. (1874). Review of Nova Scotian diurnal Lepidoptera. Proc. and Trans. Nova Scotian Inst. Nat. Sci. 1870: 18-27. LINNAEUS, GC. (1746). Fauna Sueciea. Ed. 1, p. 279. Upsala. LINNAEUS, C. (1758). Systema naturae. Ed. 10, Vol. 1. Holmiae. LINNAEUS, C. (1761). Fauna Suecica. Ed. 2, p. 359. Stockholmiae. LINNAEUS, C. (1767). Systema naturae. Ed. 12, Vol. 1, p. 890. Holmiae. McDuNNouéH, J. H. (1938). Check list of Lepidoptera of Canada and the United States of America. I. Macrolepidoptera. Mem. S. California Acad. Sci. 7. McDunnoucH, J. H. (1939). Check list of Lepidoptera of Canada and the United States of America. II. Microlepidoptera. Mem. S. California Acad. Sci. 2. MEAD, T. L. (1870). Miscellaneous notes. Extension of habitat of Pieris rapae, Linn. Canadian Ent. 2: 36. MEyRIckK, E. (1914). Hyponomeutidae, Plutellidae, Amphitheridae. In Lepidopterorum Catalogus, ed. by H. Wagner, pt. 19. W. Junk, Berlin. MINOT, C. S. (1869). Cabbage butterflies. American Ent. 2: 74-77. Moss, J. E. (1933). The natural control of the cabbage caterpillars, Pieris spp. J. Animal Ecol. 2: 210-231. MUGGERIDGE, J. (1943). The white butterfly (Pieris rapae L.) II. Parasites of the butterfly. New Zealand J. Sci. and Tech. 25A: 1-18. Norris, M. J. (1935). A feeding experiment on the adults of Pieris rapae L. (Lepid. Rhop.). Entomologist 68: 125-127. ONTARIO DEPARTMENT OF AGRICULTURE. (1963). 1963 Ontario Vegetable Production Recommendations. Ontario Dept. Agric. Publ. 363. RICHARDS, O. W. (1940). The biology of the small white butterfly (Pieris rapae), with special reference to the factors controlling its abundance. Animal Ecol. 9: 243-288. RILEY, C. V. (1883). Report of the Entomologist, 1883. U.S. Dept. Agr., Washington. RITCHIE, A. S. (1869). Notes on the small cabbage butterfly, Pieris rapae. Canadian Nat. and Quart. J. Sci. (N.S.) 4: 293-300. ROBERTSON, P. L. (1939). Diamondback moth investigations in New Zealand. New Zealand J. Sci. and Tech. 20A: 330-340. ROESEL, A. J. (1746). Der Monatlich-Herausgegebenen Insecten-Belustingung. Vol. 1, classes 4, plate 10. SAUNDERS, W. (1876). Notes of the year. The English cabbage butterfly (Pieris rapae), 6th Ann. Rep. Ent. Soc. Ontario, 1875: 31-32. 74 SCHIFFERMULLER, I. S. and M. DENIS. (1776). Systematisches Verzeichniss der Schmetterlinge der Weinergegend, p. 187. A. Bernadi, Vienna. SCHRANK, F. (1801). Fauna Boica. Vol. 2, pt. 1: 152. J. W. Krull, Ingolstad. SCHRANK, F. (1802). Fauna Boica. Vol. 2. pt. 2, p. 169. J. W. Krull, Ingolstadt. SCUDDER, S. H. (1887). The introduction and spread of Pieris rapae in North America, 1860-1886. Mem. Boston Soc. Nat. Hist. 4: 53-69. STEPHEN, W. P. and R. D. Birp. (1949). The effect of barometric pressure upon oviposition of the imported cabbageworm, Pieris rapae (L.). Canadian Ent. 81: 1382. TANADA, Y. (1953). Description and characteristics of a granulous virus of the im- ported cabbageworm. Proc. Hawaiian Ent. Soc. 15: 235-260. THOMPSON, W. R. (1951). A catalogue of the parasites and predators of insect pests. Sect. 2. Host parasite catalogue. Pt. 1. Hosts of the Coleoptera and Diptera. Comm. Inst. Biol. Cont. Ottawa. TWINN, C. R. (1924). Studies in the life history, bionomics and control of the imported cabbage- -worm in Ontario. 54th Ann. Rept. Ent. Soc. Ontario, 1923: 82-86. WALSINGHAM, LorpD and J. H. DurRANT. (1897). The diamond-back moth: Plutella cruciferarum, Z. (1843), a synonym of Cerastoma maculipennis, Crt. (1832). Ent. Mon. Mag. 33: 173- 175. ZELLER, O. (1843). Ueber Phalaena Tin. wylostella Lin. Stett. Ent. Zeit. 4: 281-283. (Accepted for Publication: April 10, 1963) O The Biology and Control of the Pepper Maggot, Zonosemata Electa (Say) (Diptera: Trypetidae) in Southwestern Ontario W. H. FooTt Research Station, Research Branch, Canada Department of Agriculture, Harrow, Ontario Introduction The pepper maggot, Zonosemata electa (Say), is a relatively new insect pest in Canada. Prior to 1956 its known distribution was limited to the United States in an area extending from New York and Massachusetts to Indiana and southward to Florida and Texas (Anon., 1959). In 1956, a small infestation occurred in a field of peppers near Harrow in south- western Ontario. Meanwhile there has been a rapid spread and increase in the severity of attack. Host crops of the pepper maggot in southwestern Ontario are peppers and tc a much lesser extent eggplants. Horse nettle (Solanum carolinense L.) is a wild host in Canada and the United States. In addition, several other weeds of the Solanaceae and tomato have been reported as hosts in the United States (Anon., 1959). This paper covers two years of investigation into the biology and control of the insect. Methods and Materials Bison Pupae, collected each spring from fields which had been infested ae previous year, were buried in three inches of soil below a cheesecloth cage. Thus information was provided on pupal mortality, time of adult emergence, sex ratio, and possible parasitism. Proc. Entomol. Soc. Ont. 93 (1962) 1963 75 : Data on copulation, oviposition, and general habits of the adults were obtained by observation of flies in the field and in cages in an insectary. The duration and mortality of egg and larval stages was determined by dissecting infested pepper fruits at frequent intervals throughout the summer. Additional information was derived from experiments in a rearing room with an average temperature of 75.3°F. during 16 hours of artificial illumination and 8 hours of darkness. 3 Soil taken from various depths in infested fields was sifted in the fall _to ascertain the depths at which pupation occurred. In addition to investigations with peppers as the host, observations were made of infestations in the fruits of horse nettle. Control In 1961, two fields of peppers were divided into one-fortieth of an acre plots, and a third into one one-hundredth of an acre plots. Two varie- ties of peppers, Keystone Resistant and a locally grown unnamed variety, were planted. In the two fields with the largest plots 50 per cent Thiodan wettable powder’ at 0.75 pounds actual per acre, 85 per cent Sevin wettable powder’ at 1.7 pounds actual per acre, and Sevin 4 Flowable (4 pounds per gallon) were tested. Materials used in the third field were the two formula- tions of Sevin at the same rates as above and 50 per cent Dylox wettable powder’ at 1.0 pound actual per acre. In 1962, one field was divided into one thirty-sixth of an acre plots and a second into one seventy-seconds of an acre plots. These were sprayed with five materials as follows: 50 per cent Thiodan wettable powder at 0.75 pounds actual per acre; 50 per cent Dylox wettable powder at 1.0 pound actual per acre; 25 per cent malathion wettable powder", 85 per cent Sevin wettable powder, and Sevin 4 Flowable, each at 1.5 pounds actual per acre. All materials were applied with a knapsack sprayer at weekly intervals from early July to late August. Each treatment was replicated three times in randomized blocks. The control obtained in 1961 was measured in percentages of peppers infested and by the total numbers of living larvae per treatment. In 1962, control was measured by the numbers of eggs deposited per plot and by the percentages of peppers subsequently infested with larvae. Differences in infestation were tested for ie by Duncan’s Multiple Range Test (Duncan, 1955). General Biology Adults and Eggs Adult emergence commenced on July 5 in 1961, and on June 28 in 1962. In 1962, the peak number of flies in a severely infested field occurred 18 days after emergence began. Thereafter a rapid decrease 1n numbers occurred and no flies were observed after July 24. There was evidence that very small numbers were present until early August because a few viable eggs were found in mid-August. The ratio of females to males in adults reared from pupae was 1.3:1.0 and of flies captured in the field 1.4:1.0. Caged flies lived an average of 17 days when supplied with strips of absorbent cotton saturated with a seven per cent sucrose solution. However, two females lived for 40 days in an insectary and escaped with vigorous 16,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzc-dioxathiepin-3-oxide. Niagara Brand Chemicals, Burlington, Ont. *1-naphthyl N-methylcarbamate. Union Carbide Chemicals Co., New York, N.Y. 39,0-dimethyl (2,2,2-trichloro-1-hydroxyethyl) phosphonate. Chemagro Corporation, New York, N.Y. Samoa ys (thoaycanpony aad 0,0-dimethyl phosphorodithioate. Niagara Brand Chemicals, Burlington, nt. 76 flight when the cage door was cpened to replenish the food. A male lived for 55 days in a cage in a greenhouse when fed the sucrose solution. In addition, the male fly fed extensively on honeydew from green peach aphids which infested a pepper plant provided for shade. As honeydew is common from aphid infestation the flies possibly utilize it as a source of carbohydrate in nature. The precise flight range of the adults is not known, but a light infesta- tion was found in a planting of peppers which was one- half mile from any known infestation of the insect. In the few instances in which it was observed in the field, copulation always occurred on the lower side of a pepper leaf. In the insectary it occurred on the top and on the sides near the top of cages. Engaged pairs were not easily disturbed in either the field or the insectary. In 1962 ovi- position in nature was underway by July 4, which indicated a maximum preoviposition period of six days. On caged pepper plants in an insectary females made rapid excursions over the surface of a fruit, often in a sideways movement. Frequent stops were made to insert the ovipositor into the wall of the pepper. Later examination showed that over one-half of the holes contained no eggs. Holes without eggs were also observed in peppers in the field. As investigators have been unable to rear this insect it was necessary to dissect adult fe- males captured in the field to estimate their fecundity. The average number of eggs in 18 females was 20.6 and the maximum was 43. The egg, a description of which was published by Peterson (1923), extended through the thin wall of small peppers and projected into the cavity of the fruit. In larger peppers with thick walls eggs were entirely embedded in the flesh. No particular area on the pepper appeared to be preferred for oviposition. Newly hatched larvae were found in nature by July 16 in 1962, which indicated a maximum incubation period of 12 days. Eggs which appeared to be recently laid hatched in 10 days when they were removed from the wall of peppers and placed on moist filter paper in petri dishes in a rearing room at an average temperature of 75.3°F. Mortality of eggs was low. Only 6 of 550 eggs laid in unsprayed peppers failed to hatch. Information on the relationship of size of peppers to the numbers of eggs deposited was obtained by examination of samples of peppers of various sizes on July 9, 16, and 23, 1962. It was found that the number of eggs deposited was positively correlated with the size of the pepper (Table 1). When a small group of field-captured females was placed in a cage in an insectary with a pepper plant bearing two fruits five-eighths of an inch and another one and three-quarters inches in diameter, 49 eggs were laid in the larger pepper and 3 in each of the small peppers. The maximum number of eggs laid per fruit in the field was 18. Seven to 11 eggs per pepper were common in a heavily infested field. Larvae In 1961 the first mature larva was found on August 8 and the last on September 19. In 1962 mature larvae were found from August 3 to Septem- ber 19. A minimum of 18 days was required for development of the larvae. The average developmental period of a small number of larvae in a rearing room at an average temperature of 75.3°F. was 12 days. If the eggs extended into the cavity of a fruit the larvae on hatching commonly crawled over the inner surface of the pepper until they reached 77 the placenta, penetrated the spongy placental tissue and fed there until mature. Full-grown larvae bored through the wall of the pepper, dropped to the ground and entered the soil for pupation. When larvae hatched from eggs embedded in the wall they usually bored through the wall to the inner surface and then moved to the placenta. In a few instances feeding was confined entirely to the wall, in others both the wall and placenta were utilized. Mortality of the larvae was high. In unsprayed peppers 32 per cent of the larvae died before they had done any detectable feeding. Pupae In nature mature larvae usually pupated within the top two inches of soil. Of 96 pupae obtained by sifting soil in an infested field 93 were in the top two inches, two were at a depth of two to four inches, and one was at a depth of four to six inches. In a very few instances pupae were found in the fruit. Soil was not essential for pupation because larvae rapidly changed to pupae in paper bags, boxes, and on a table top. Mortality in the pupal stage was high. Of 97 pupae which were buried in three inches of soil only 28 produced adults. When 30 puparia that produced no flies were dissected 22 were found to contain almost completely developed adults which were dark and soft. Of the remainder, four con- tained dried, shrivelled pupae, and four were empty. No parasitism or predation was observed. Only one generation occurred per season. Development in Horse Nettle Horse nettle is not plentiful in southwestern Ontario. However, four small patches of it were found, two of which were closely observed in 1962. One patch extended along a fence line several hundred yards from a field of peppers severely infested by the pepper maggot. Eggs of the pepper maggot had been deposited in the fruits of the weed but no larvae were found. Dissection of the fruits revealed that the interiors had been consumed by unidentified lepidopterous larvae. Such larvae may have either destroved the eggs or larvae of the pepper maggot while feeding, or had consumed so much of the fruit that there was insufficient food left for the development of the maggot. The second area of horse nettle was in the center of a corn field at least one-half mile from a pepper field. No infestation was detected until late August. By September 14 many fruits contained pepper maggot larvae which ranged from 3 to 10 mm. in length. Pupation began by September 19 but larvae were still present on October 8. Lepidopterous larvae were absent from this patch. Pupae obtained from larvae which developed in horse nettle were con- siderably smaller than those from peppers. The average length and width of 60 pupae from horse nettle was 6.8 and 3.1 mm., and of 100 pupae from peppers was 7.5 and 3.5 mm. Control 1961 Tests Infestation in the untreated plots of the two fields with the larger plots was too low to permit evaluation of the insecticides. Infestation in the third field was light. It was found that Dylox and the two formulations of Sevin each gave control significant at the one per cent level (Table 2). Differences between treatments were not significant. 78 1962 Tests No infestation occurred in the field divided into one seventy-seconds of an acre plots, but infestation was severe in the field of larger plots. The numbers of eggs deposited in peppers in all treated plots were significantly less at the one per cent level than in the untreated plots (Table 3). Reduc- tion of egg deposition by Sevin 4 Flowable was significantly better at the one per cent level than was obtained with Dylox or Thiodan. The flowable formulation of Sevin was significantly better than Sevin wettable powder at the five per cent level. In the malathion plots eggs were significantly fewer at the one per cent level than in the Dylox plots, and at the five per cent level than in the Thiodan plots. Analyses of the percentages of peppers damaged by feeding larvae showed that all materials except malathion gave reductions from the un- treated plots which were significant at the one per cent level (Table 3). The reduction by malathion was almost significant at the one per cent level. Dylox gave control which was significantly better than malathion at the five per cent level. Dissection of some of the peppers sampled from treated and untreated plots showed that many newly hatched larvae apparently died before feed- ing. The percentages of larvae which died were as follows: untreated, 32.1; malathion, 39.5; Sevin 4 Flowable, 51.3; Sevin wettable powder, 51.6; Thiodan, 68.3; and Dylox, 79.2. In one instance 17 eggs were laid in a pepper in a Dylox-treated plot and although all hatched no larvae survived. It was not determined whether the increased mortality of larvae in treated peppers was due to absorption of a lethal dose of insecticide from the egg membranes during hatching, or to a systemic translocation of the ma- terials through the walls of the peppers. Of the materials tested in 1961 and 1962, Thiodan and malathion were the best suited for use in pepper fields. Thiodan was the most efficient because it (1) was second to Dylox in effectiveness against the pepper maggot, (2) gave excellent control of aphids, and (3) could be applied within one day of harvest. Malathion, which is presently recommended for use by growers, gave better control of the adults than Thiodan, but permitted a larger infestation of larvae. Growers who applied the former in early July obtained excellent control, but when applications were delayed severe infestations occurred. Malathion gave only poor to fair control of aphids. Dylox and the two formulations of Sevin encouraged major increases of aphids and could not be used by growers without the addition of an aphicide. In addition, because Dylox cannot be used within 21 days of harvest, it would be of little use to growers who harvest fruits in the green stage. Discussion Literature related to detailed biological studies of the pepper maggot appears to be limited to two bulletins, one by Peterson (1923) and the other by Burdette (1935). Both of these workers conducted their investi- gations in New Jersey where the pepper maggot has been an important pest of peppers since about 1915. A general comparison of their observa- tions with those of the author showed that adults emerged several days later in Ontario and were not in the fields for as long a period as in New Jersey. The minimum developmental periods of the eggs and larvae were slightly longer in Ontario. 19 Whereas there was little difference in the numbers of each sex cap- tured in the field in Ontario, males comprised 88 and 80.5 per cent of adults captured by Peterson and Burdette, respectively. However, when Burdette reared adults from puparia he observed that the numbers of each sex were approximately equal, as was found by the author. Peterson dissected 10 females and found that the numbers of eggs contained therein ranged from 6 to 39. This indicated to him that 40 to 50 might be the maximum number deposited by one female. aa for this assumption was provided in the author’s work. Peterson and Burdette stated that peppers 0.5 to 1.5 inches in diameter were most subject to attack. In the present investigation it was found that more peppers of this size contained eggs but it appeared to be related to the fact that this was the most common size at the time the adults were abundant. The females continued to oviposit in peppers when they grew larger. Also, when peppers of two sizes were initially provided in a cage in an insectary, much larger numbers were laid in the larger pepper. _A high mortality of pupae observed by the author was noted also by Burdette, who found in three successive years only 20.8, 10.0, and 25.8 per cent of the pupae buried in three inches of soil produced adults. Neither Peterson nor Burdette were able to keep caged flies alive for more than three days or to obtain oviposition by females under many dif- ferent environmental! conditions tested. In the present work some flies were kept alive for several weeks and eggs were obtained. No explanation is available for later development in horse nettle than in pepper. As the former host was in a field of corn, a cooler microclimate produced by shade might have caused a longer developmental period for each stage of the insect. The small amount of food available per fruit of horse nettle might also cause a lengthening of the development of larvae. It is possible that development of the insect in horse nettle is normal and that the earlier availability of pepper fruits allowed an expansion in | the population of flies which emerged early. The excellent control provided by Dylox and the two formiuione of Sevin in 1961 was not as evident in 1962. The decreased control obtained in 1962 appeared to be due to (1) the much larger numbers of flies present and (2) the relatively small plots which permitted adults to move from one plot to another in a single flight. This assumption is based on evidence that malathion, which gave the poorest control in small plots, gave excellent control when applied by growers to entire fields of peppers. Summary Zonosemata electa (Say) was first reported in Ontario in 1956 and since then has become an important pest of peppers and to a much lesser extent eggplants. In two years of investigation the adults appeared in late June or early July and reached a peak about mid-July. Eggs were deposited in the walls of pepper fruits and required 10 to 12 days to hatch. Newly hatched larvae moved along the inner wall of the fruit to the placenta where they fed for a minimum of 18 days. Mature larvae left the pepper and entered the soil to pupate. A low mortality of eggs but high mortalities of larvae and pupae were observed. There was only one generation per year. Various degrees of control were obtained with 50 per cent Dylox wettable powder, 50 per cent Thiodan wettable powder, 25 per cent mala- 80 thion wettable powder, Sevin 4 Flowable, and 85 per cent Sevin wettable powder. Of these, Thiodan at 0.75 pounds actual per acre showed the most promise. Literature Cited ANON. (1959). Status of some important insects in the United States. Pepper maggot (Zonosemata electa (Say) ). U.S.D.A. Coop. Econ. Ins. Rep. 9: 721-722. BURDETTE, R. C. (1935). The biology and control of the pepper maggot, Zonosemata electa Say, Trypetidae. N.J. agric. Exp. Sta. Bull. 585. DuNCAN, D. B. (1955). Multiple range and multiple “f” tests. Biometrics 11: 1-42. PETERSON, A. (1923). The pepper maggot, a new pest of peppers and eggplants. N.J. agric. Exp. Stay pull B7oe TABLE 1. Average numbers of eggs deposited by the pepper maggot in peppers of various sizes Diameter oF peppers Number Average number of Date (inches) examined ege’s per pepper duly 9 0.50-0.75 15 13 0.75-1.00 30 DED, POO=25 18 3.6 July 16 0.75-1.00 10 2G 1.00-1.50 44 4.1 1.50-2.00 50 4.8 2.00-2.50 22 5.8 July 23 1.25-1.75 26 13 1.75-2.25 35 DEE 2.25-2.75 47 6.1 TABLE 2. Percentages of fruits damaged and total numbers of pepper maggot larvae in peppers from various treatments in 1961 Per cent Significant differences? Significant differences? Treatment of fruits 5 percent’ 1 per cent Total 5 per cent 1 per cent damaged? level level larvae level level Sevin 85% w.p. 1b a a 133 a a Sevin 4 Flowable 2.2 a a lee a a Dylox 50% w.p. 3.3 a a De a a Untreated 13.3 | b b 15.3 b b aRach figure is the mean n of three - replicates of 60 peppers each. bTf treatment means do not share a common letter they are significantly different (Duncan, 1955). TABLE 3. Egg deposition and percentages of fruits damaged by the pepper maggot in peppers from various treatments in 1962 Number Significant differences» Per cent Significant differences? Treatment of eggs 5 per cent 1 percent of fruits 5 per cent 1 per cent deposited2 level level damaged¢ level level Sevin 4 Flowable 63.7 a a 43.0 ac a Malathion 25% w.p. 69.7 ab aa ATi be ab Sevin 85% w.p. 83.3 be ab 46.3 ac a Thiodan 50% w.p. 92.0 € b ¢ Slat aac a Dylox 50% w.p. 98.0 c b Sonik a a Untreated 156.0 d d 62.7 d b aKach figure is the mean of three replicates of 35 peppers each. bIf treatment means do not share a common letter they are significantly different (Dunean, 1955). cach figure is the mean of three replicates of 115 peppers each. (Accepted for Publication: February 28, 1963) 81 lil. SUBMITTED PAPERS Mosquitoes in and about Windsor, Ontario W. G. BENEDICT Department of Biology Essex College Assumption University of Windsor Abstract A survey of mosquitoes in the city and suburbs of Windsor, Ontario was completed in 1962. The following species were found: Aedes aurifer | (Coquillet), A. dorsalis (Meigen), A. intrudens Dyar, A. stimulans (Walk- er), A. trichurus (Dyar). A. triseriatus (Say), A. trivittatus (Coquillett) , A. vexans (Meigen), Anopheles punctipennis (Say), A. quadrimaculatus (Say), A. walkeri Theobald, Culex pipiens Linnaeus, C. restuans Theobald, C. territans (Walker), Mansonia perturbans (Walker) and Psorophora ciliata (Fabricius). The presence at Windsor of the typically western species, Aedes dorsalis, of salt and alkaline marshes is the first report of this Mosquito in southern Ontario. Culex pipiens, the northern house mos- quito, Aedes stimulans, A. vexans and A. dorsalis were, respectively, by far the most common species in order of abundance in the 20 square mile area investigated. Introduction The Metropolitan Windsor Health Unit on December 7, 1961 extended its public health program into mosquito control at a meeting in City Hall, Windsor. An advisory Committee to consider and report on the problem, methods and costs of mosquito control in the Windsor area was formed with Dr. John Howie, Director of the Metropolitan Windsor Health Unit, as chairman. While the ultimate objective of the Committee was to present alternative plans for mosquito control throughout Essex County, the im- mediate objective was to make a study of mosquito species which could be found, firstly, in the Windsor area and, secondly, throughout Essex County. The purpose of the study was to take this first step in the control program and then to investigate the possibility of mosquito-borne diseases under present conditions and of ridding Windsor and its suburbs of the pestilence of biting mosquitoes. ; Methods and Materials The majority of the mosquitoes were collected as larvae from natural habitats and were brought into the laboratory. Adults that emerged from some of these larvae in the laboratory were also collected for identification. Proc. Entomol. Soc. Ont. 93 (1962) 1963 82 Other adult mosquitoes were obtained in the field while they were flying above small bodies of water, or attracted to the collector’s skin, or caught in light traps. Three times weekly, suitable locations such as animal drink- ing troughs, pools, drainage ditches, rain barrels, wheel ruts, tree stumps, and slowly flowing streams were visited and revisited for mosquito larvae from May 15 to September 15. Suitable habitats for flying or resting adult mosquitoes were found amongst shrubs in gardens, in woodlots and fields, above ponds, and in houses and other buildings. Three light traps were located and relocated throughout the 20 square mile survey area during the summer and were attended daily. For each species collected, larvae and adults were preserved and the terminalia of male mosquitoes were mounted on permanent slides. All mosquitoes were identified by the use of taxonomic keys (Matheson, 1944; Carpenter and LaCasse, 1955; Defence Research Board, 1957; Steward and McWade, 1961) to the species in both the larval and the adult stages wherever both could be found. In add.tion to the collection and identification work, daily lccally-published weather data was recorded, and observations were made of the biology of the mosquitoes of the area. Results The following mosquitoes were found in the Windsor area: Aedes aurifer (Coquiliet), A. dorsalis (Meigen), A. intrudens Dyar, A. stimulans (Walker), A. trichurus (Dyar), A. triseriatus (Say), A. trivittatus (Coquil- lett), A. vewans (Meigen), Anopheles punctipennis (Say), A. quadrimacu- latus (Say), A. walkeri Theobald, Culex pipiens Linnaeus, C. restuans Theo- bald, C. territans (Walker), Mansonia perturbans (Walker) and Psoro- phora ciliata (Fabricius). During the four month period, 636 samples of larvae were taken from rain filled containers and small bodies of water. The species are listed according to the first date on which they were collected. May 14—Aedes vexans, May 17—Culex pipiens and restuans, May 19—Aedes dorsalis, June 9—Culex territans, August 17—Anopheles quadrimaculatus, and August 19—Anopheles punctipennis. In the same period, 658 samples of individual mature females were caught as they were attracted to the collector’s exposed skin. The species are recorded according to the first date on which they were caught. May 19—Aedes stimulans and dorsalis, May 26—Aedes vexans and Culex pi- piens, May 29—Aedes aurifer (near LaSalle), June 2—Aedes trichurus and trivittatus, June 5—Aedes intrudens, June 7—Culex territans, June 14— Culex restuans, July 5—Aedes triseriatus, July 17—Anopheles walkeri, July 19—Anopheles punctipennis, and August 21—Psorophora ciliata (near Maidstone). The light traps attracted many insects but few mosquitoes. One mos- quito species, Mansonia perturbans, however, was caught only by this method. The following mosquitoes were found in light traps during the month and in the numbers indicated. May—Aedes stimulans (8) and vexans (5), and Culex pipiens (1), June—Culex territans (2) and restuans (1) and Aedes vexans (6), July—Aedes vexans (12), Mansonia perturbans (1), Culex territans (1) and pipiens (3), August—Culex pipiens (7) and territans (4), and Aedes vexans (17), September—Aedes dorsalis (1). A quantitative analysis of larvae and adults collected during the survey is summarized in Table 1. 83 TABLE 1. Relative Abundance of Mosquitoes in 1962. LARVA COLLECTIONS Aedes vexans 28.36 Genus Species Percent Aedes dorsalis 4.8 Culex pipiens 74.5 Aedes trivittatus 0.94 Culex restuans G2 Aedes | triseriatus 0.94 Culex territans 13 Aedes trichurus 0.47 Aedes vexans 13.8 Aedes intrudens 0.47 Aedes dorsalis Ze Aedes aurifer 0.47 Anopheles . punctipennis 1.4 Mansonia _ perturbans 0.94 Anopheles quadrimaculatus 0.2 Psorophora Ene ea: 0.47 ADULT COLLECTIONS Anopheles punctipennis 0.47 Genus - Species Percent Anopheles quadrimaculatus 0.47 Aedes stimulans 61.2 Anopheles walkeri 0.47 All the adult members of the genus Culex were taken over ditches containing emerging larvae; thus a true count could not be obtained. It is for this reason, their numbers were not considered in the adult collection percentages. It is obvious, however, that since 80% of the larvae taken were Culex, adult Culex mosquitoes would have out- numbered Aedes in this particular survey by at least two to one. Another two to one ratio may be noted within the genus Aedes, namely, the ratio of adults: larvae in both A. vexans and A. dorsalis. Discussion Although the habitats and the habits of the mosquitoes that were found to be most abundant in the Windsor area were studied, they are well known. This paper may serve only as a useful locality record. As pointed out by a reviewer of the manuscript it is surprising that Aedes canadensis was not found in the Windsor area as this species is reputedly abundant throughout southern Ontario. However, there seems to be no confusion with A. canadensis (Theobald) of the newly reported A. dorsalis in the Windsor area since the identity of the latter species and other samples was checked authoritatively by the Entomology Research Institute. Acknowledgements This study was supported by a grant from the Metropolitan Windsor Health Unit. The writer is grateful to the Director, Dr. John Howie, Medical Officer of Health (Committee Chairman), Mr. H. R. Boyce, Entomologist, Canada Department of Agriculture, Harrow, Mr. Robert T. Bailey, Commissioner of Works, Windsor, Mr. Harry O. Brumpton, Parks and Recreation Commissioner, Windsor, Mr. R. W. Travis, Administrative Assistant to City Manager, Windsor (Committee Secretary), and to Mr. Ralph Gault and Mr. Douglas Copeman whe carried out the field work and assisted in identifying the species. Acknowledgement of the positive identi- fication of specimens of Aedes dorsalis (Meigen) is also due to Dr. J. R. Vockeroth, Entomology Research Institute, Department of Agriculture, Ottawa. Literature Cited CARPENTER, S. and W. LaCasse. (1955). Mosquitoes of North America. Univ. California Press, Berkley and Los Angeles. 360p. DEFENCE RESEARCH BoarbD. (1957). Supplement to Interservice Manual on Pest Control. Dept. Nat. Defence, Ottawa. 95p. MATHESON, R. (1944). Handbook of the Mosquitoes of North America. Comstock Pub. Co., Ithaca. 314p. STEWARD, C. C. and J. W. McWapbkr. (1961). The Mosquitoes of Ontario (Dintaes Culicidae). With keys to the species and notes on distribution. Proc. a Soc. Ont. 91 :121-188. (Accepted for Publication: May 3, 1963) 84 Control of Caterpillars on Late Cabbage in The Ottawa Valley, 1960-1961 L. M. CAss’ In the Ottawa Valley, late plantings of cabbage are attacked every year by caterpillars of three species, namely: the imported cabbageworm, Pieris rapae (L.), the diamondback moth, Plutella maculipennis (Curt.), and the cabbage looper, Trichoplusia ni (Hbn.). Control is based on a single pre-heading application of a residual insecticide, such as endrin, plus three or four applications of a less stable material after head forma- tion. Harcourt and Cass (1959) showed that four post-heading applica- tions of Phosdrin, Guthion, or parathion controlled caterpillars attacking the late crop. Cass (1961), showed that a combination of malathion and Perthane was effective for the same purpose. Two of the preceding four materiais were further appraised in 1960 and 1961, along with some promi- sing new insecticides and a commercial preparation of the bacterium Bacillus thuringiensis Berliner. Methods and Materials The experimental plots were in growers’ fields at Aylmer, Quebec. The plots, which averaged one-fiftieth of an acre in size, were arranged in four randomized blocks. The experimental areas measured three-fifths of an acre in 1960 and two-fifths of an acre in 1961. The variety of cabbage in both years was Penn State Ballhead. Table 1 lists the insecticides and the concentrations at which they were tested. The dusts were applied with rotary hand dusters at 15-25 pounds per acre of the diluted dust. The emulsible concentrates were applied with knapsack sprayers at 60-100 gallons per acre of the diluted spray. Four applications were made at 10 day intervals, beginning on August 4, 1960 and August 7, 1961. A pre-heading application of endrin dust at 0.25 Ib. of toxicant per acre was made to al! plots including the checks during the fourth week of July. Population Records To determine the relative abundance of the Lepidoptera attacking the plants, larval counts were made in the check plots at the end of August. A leaf by leaf examination of 50 plants was carried out, the sample plants being chosen at random from the central rows. The average numbers of larvae per plant were as follows: 1960 1961 Diamondback moth 6.6 Ls Imported cabbageworm 8.2 129 Cabbage looper 15 O02 As the feeding ratio of equal populations of the diamendback moth, the imported cabbageworm, and the cabbage looper is 1: 7.5: 11.6 (Har- eourt et al., 1955), it is apparent that the insecticides were evaluated es- sentially against the imported cabbageworm. Criterion of Effectiveness Effectiveness of the materials was based on caterpillar feeding injury to the plants at the beginning of harvest, September 28, 1960 and Septem- ber 29, 1961. All the plants in each plot except those in the two outside 1fntomology Research Institute, Research Branch, Canada Department of Agriculture, Ottawa, Ontario. Proc. Entomol. Soc. Ont. 93 (1962) 1963 85 ‘QUO “ST[TAYVO ‘pozwMyy] s[vorwmeyH [emnypnoisy oyzICy; 4uQ “eT[AjjeqdureD “peqytuiy AuedwoD sqyonporg umniajeg Surye : 10.0 G29 We} ted se1ods a[qeiaA ,0— x G SULULe}U0d -BIULOFITVD ‘yIVq Buong“ouy ‘sqonpoig 941[14jn Np ‘O96T UL posn snp %Eo ‘qUuQ ‘UOpdUl[Ing ‘s[eoIWeYyO purrig eaieseINg "yuOQ ‘T OJUOIOT, “epeueD so Auedwioy [IQ [Use iv We VOL :[OAST %T 42 6L 69 -[OAR] %G Je OoUVIJIUSIS IOF potinbor sousaATTIG i a ae Ra eee ee eee ee eee ae ae! S°86 6°86 LAE OLE Perce yee (OND) Tél L'08 GL? T6r 696 GLE OG T . OS a org OLL [8 L°GS LLY LVG SEE 6&0 9u09 [NU eUulLtpsoud L6L 0°98 — «60°06 6&1 GG¢ 6GE 0OT + 080 nq 6G + Nd Bp suvyjseg+uo1iyzeley g°66 OSL VL lve LGG &9E sorods .0T X 000‘0F arta PSUSUILOULLNY) * 0°86 OTL 0% T'8¢ 606 IG& GL'0 9 0U09 “NU queporyy, G66 G°96 gO Gg SVG 89E && 0 UCO [RU BU p Ore L96T 0961 T96T 096T T96T 096T ‘q[ “ot08 10d UOTE [NULLO WJ eploljoosuy JO1}U09 ode USDI1Eg Z epearry poulwmexe Jequinn JUBIIXO T, | 038 }U90.10g sjuevid edeqqey ‘T96T-096T ‘On® ‘touyAY ‘seprorqoesul snor1iea JO suoryeorjdde surpvoy ysod anoF YAIM odeqqeod 04R] UO SIe[[Id104¥d Jo [oA{UOD “T aTav L 86 buffer rows and a three-foot buffer strip at the end of each row, were examined for damage to the heads and wrapper leaves and placed in one of two grades. Grade 1 plants showed no apparent injury and corresponded to the Canada No. 1 Grade. Grade 2 plants showed sufficient injury to reduce the market value of the crop. | Differences between treatments were assessed by the multiple range test of Tukey, as given in Federer (1955). Results and Discussion Table 1 shows that malathion - Perthane, and Phosdrin again gave good to excellent control of the caterpillars. Dibrom gave good control in 1960 and moderate control in 1961. Thiodan gave moderate control when used as a dust in 1960, and excellent control when used as an emulsible concentrate in 1961. Partly from these results, the two chemicals were recommended to Ontario growers in 1963 for control of caterpillars attack- ing cole crops after head formation (Ontario Department of Agriculture, 1963). The microbial insecticide Bacillus thuringiensis gave only fair control in 1960 but excellent control in 1961. In view of these differences, further tests should be carried out to more definitely establish its value against cabbage caterpillars. Telodrin gave excellent control of caterpillars in both years. This chemical is long residual in toxicity and may not be applied to the edible portions of the plants. However, it holds considerable promise as a pre- heading treatment. Summary In 1960 and 1961, on the basis of injury to the heads and wrapper leaves at harvest, four post-heading applications of emulsible-concentrate insecticides at 10-day intervals gave the following percentages of control of caterpillars on late cabbage: Telodrin at 0.33 lb. of toxicant per acre, 97 and 99; Phosdrin at 0.33 lb., 82 and 77; and Dibrom at 1.20 lb., 81 and 72: Thiodan at 0.75 lb. per acre gave 72 per cent control as a dust and 98 per cent control as an emulsible concentrate. A combination of malathion and Perthane dusts at 0.80 and 1.00 lb. per acre, respectively, gave 86 and 80 per cent control. A commercial dust preparation of Bacillus thuringiensis Berliner at 40,000 x 10° spores per acre gave 76 and 93 per cent control. Acknowledgements The author is indebted to Dr. D. G. Harcourt, Entomology Research Institute, Ottawa, for helpful advice throughout this investigation. Literature Cited Cass, L. M. (1961). Control of caterpillars on late cabbage in central Ontario and western Quebec, 1958-1959. Proc. Ent. Soc. Ontario. 91: 49-52. FEDERER, W. T. 1955. Experimental design. Theory and application. Macmillan, Toronto. Harcourt, D. G., R. H. BAcKs, and L. M. Cass. (1955). Abundance and relative im- portance of caterpillars attacking cabbage in eastern Ontario. Canadian Ent. 87: 400-406. Harcourt, D. G. and L. M. Cass. (1959). Control of caterpillars on cabbage in the Ottawa Valley of Ontario and Quebec, 1956-1957. J. Econ. Ent. 32: 221-223. ONTARIO DEPARTMENT OF AGRICULTURE, 1963. 1963 Ontario vegetable production recommendations. Ontario Dept. Agric. Publ. 363. (Accepted for Publication: May 1, 1963) 87 K Note on Insect Hallucinations Affecting an Elderly Couple W. H. FooTtT Research Station, Research Branch, Canada Department of Agriculture, Harrow, Ontario In the fall of 1961, an elderly couple brought a sample of clover mites to the author for identification and a control recommendation. They re- turned in 1962 to report another infestation and requested the name of the chemical which had been so efficient in 1961. During a conversation the wife stated they were plagued with other insects which occurred only in their bedroom. She described them as small and white, and embedded in the blankets. They did not move when touched and appeared to be playing “possum”. Also, she was unable to kill them when they were squeezed between her fingers. The husband concurred with her statements and added that it was often necessary to rise during the night to vacuum the room before they could cbtain their proper rest. They were asked to bring a sample of the insects to the Research Station. The following day the husband returned with a bottle containing blanket fibres and several of the ‘‘insects’”. Examination by eye and micro- scope revealed only small pieces of lint enveloped by the fibres, but he could not be convinced of this fact even when he viewed the particles under magnification. He was more convinced than ever that they were very smart creatures because they could make themselves so inconspicuous. He stated further that there was a small, black insect in the bottle which had been in his hair and had bitten him. This object was found to be a small piece of coal or ash which had become lodged in his luxuriant head of hair. He explained that normal washing of the hair had failed to dislodge this “insect’’, but washing with coal oil resulted in five cf them falling out. He was concerned that a reinfestation might occur. Again he could not be convinced of the true nature of his troubles, even when he was allowed to probe the object. with a dissecting needle until it split into several pieces. This case was similar to that experienced by Miller (1954) in that two people shared the hallucinations. Unlike the couple interviewed by Miller, who were despondent and ashamed of their infestation, the couple in the present case were cheerful and spoke freely of their troubles. How- ever, as with Miller, it was considered prudent to sympathize with them, to advise that judicious use of a chemical would eventually solve their problems and to offer any additional help possible. The gentleman departed in a very optimistic mood and has not returned in the intervening months. Literature Cited - Miuuer, L. A. (1954). An account of insect hallucinations affecting an elderly couple. Canad. Ent. 86: 455-457. (Accepted for Publication: February 22, 1963) 88 A Dolichopodid Predacious on Larvae of CULEX RESTUANS Theob. J. HK. LAING' and H. E. WELCH Entomology Research Institute for Biological Control, Research Branch, Canada Department of Agriculture, Belleville, Ontario Larvae of the mosquito Culex restuans Theobald in experimental mosquito ponds were attacked by a dolicnopodid fly. These ponds are near Chatterton, at the Field Station of the Entomology Research Institute for Biological Control, Belleville. The flies were identified by Dr. J. R. Vockeroth of the Entomology Research Institute, Ottawa, as the dolichopo- did, Dolichopus gratus Lw. Observations of the behaviour and effective- ness of the fly were made in July and early August at the height of the breeding season for C. restuans in the Belleville area. The adult flies rest in the sunlight at the edge of the ponds from where they launch out in foraging flights over the water surface. They frequently, and apparently randomly, dip into the water for larvae. On the average only one in ten of these dives resulted in a successful catch of a mosquito larva. When a larva was caught the fly returned to the edge of the pond, holding the larva in its forelegs and mouthparts. It then consumed the larva and left only the hard parts of the body, the siphon and the head capsule. Consumption of the larva usually took less than five minutes, but varied depending on the size of the larva. The fourth instar larva seemed to be taken more often than the other instars, possibly because of their larger size, or of their habit of remaining motionless at the surface of the water for longer periods of time. Following the consumption of the mosquito larva the fly remained for about a half hour at the edge of the pond before it resumed its foray for food. Such feeding occurred only during the daylight hours, and was particularly active at those pools receiving direct sunlight. This predaceous activity lasted from about mid July until mid August when the mosquito larvae were most plentiful in the ponds. At their maximum abundance the flies numbered from one to two hundred at an eight-foot square pond. In this pond there were about 8,000 larvae (esti- mated from egg raft counts), and these disappeared in a five week period, mainly due to the predation of the dolichopodid. As the mosquito larvae disappeared, so did the flies and by August 20th both species had disappeared. These data suggest that one hundred flies could destroy a population of 1,000 mosquito larvae in a natural pool in as little as five days. This report is not unusual, though it is probably the first such report for Canada. Several authors recorded similar predation against tropical and temperate mosquitoes: Howard, Dyar and Knab (1912) recorded the predation of mosquito larvae in Panama by dolichopodids; Bishop and Hart (1931) found that Dolichopus renidescens M. and B., D. nigricauda V.D., D. appendiculatus V.D. and D. walkert V.D. fed on mosquito larvae in Colorado, and also that the flies would attack larvae in laboratory aquaria; Williams (1939) recorded that several species of dolichopodids were effective predators of mosquito larvae and pupae; more recently Travis (1947) observed that the dolichopodid Paracleius germanus Parent captured and fed on larvae of Culex annulirostris Skuse and Culex quin- quefasciatus Say in Guam in the South Pacific; and Darrow (1949) in her study of water levels and their effect on mosquito numbers, recorded that 1Student Assistant. Proc. Entomol. Soc. Ont. 93 (1962) 1963 89 often when mosquito larvae were stranded in shallow pools they were consumed by species of two dolichopodid genera, Thinophilus sp. and Pelastoneurus sp. Literature Cited BISHOP, SHERMAN C., and RICHARD C. HART. (1931). Notes on some natural enemies of the mosquito in Colorado. J.N.Y. Entomol. Soc. 39 (1): 151-157. DARROW, EpITH M. (1949). Factors in the elimination of the immature stages of Anopheles quadrimaculatus Say in a water level fluctuation cycle. Am. J. Hyg. 50 (2): 207-235. Howarp, LELAND O., H. G. Dyar, and F. KNAB. (1912). The mosquitoes of: North and Central America and the West Indies. Carnegie Institution of Washington Publi- cation No. 159, 1 520 pp. TRAVIS, B. V. (1947). Three species of flies predaceous on mosquito larvae. Proc. Entomol. Soc. Wash. 49 (1): 20-21. WILLIAMS, FRANCIS X. (1939). Biological studies in Hawaiian water-loving insects Part 3, Diptera or flies. B. Asteiidae, Syrphidae and Dolichopodidae. Proc. Hawaiian Entomol. Soc. 10 (2): 281-3815. (Accepted for Publication: January 16, 1963) Food Preferences of the Six-Spotted Leafhopper, Macrosteles fascifrons (Stal) R. J. MCCLANAHAN The six-spotted leafhopper has been of major importance on occasion in several recent years in southwestern Ontario. The main damage by this insect is through the transmission of aster yellows virus to such hosts as carrots, lettuce, celery, flax and sunflower. The incidence of virus disease in a certain host is presumably influenced by the host preference of the viruliferous leafhoppers. Kunkel (1931) used groups of viruliferous six-spotted leafhoppers to establish the extensive host range of aster yellows virus, and it can be concluded that these insects will feed on a great many plants if they are given no other choice. Several hosts, including tomatoes and some varieties of potato, proved lethal to the leafhoppers after several days feeding. Lee and Robinson (1958) conducted field studies on the preference of the six- spotted leafhopper for aster, carrot, lettuce, parsley and flax. Populations ~ were highest on lettuce in June and July, and on carrots in August. Wallis (1962) found six-spotted leafhopper populations on 33 cultivated plants (mostly vegetables) and 2 weeds, and the recorded numbers per 100 net sweeps indicated the preferred plants were bindweed, carrot, celeriac, celery and endive. Field studies at the Chatham laboratory indicated that sampling crops by net sweeps gave only a gross estimate of the population. The catches were influenced by the facility with which the crop could be swept; for example, many more leafhoppers were swept from carrots than from lettuce. The maturity of the crop and transient weather conditions in- 1Contribution No. 30, Entomology Laboratory, Research Branch, Canada Department of Agriculture, Chatham, Ontario. Proc. Entomol, Soc. Ont. 93 (1962) 1963 90 fluenced the numbers of leafhoppers. This paper deals with the progress of recent investigations on the host preference of the leafhoppers under controlled conditions. Materials and Methods The cage used for preference studies (Figure 1) was circular, 24 inches in diameter and 12 inches high. The plywood bottom had 9 holes, 3 inches in diameter, near the outside edge, and spaced at equal intervals. The cage top, of 1/8 inch plexiglass, was held in place by a central iron rod and secured with machine nuts. The side was cotton, stapled to the bottom and held over the edge of the top with a drawstring. Several legs held the cage up from the floor and allowed the 3-inch pots to sit in the holes, supported by their rims. Fic. 1. Cage used for leafhopper preference studies. The experiments were conducted in a growth room held at 20 + 1° C. and 45 per cent relative humidity. A light bank provided 700 ft.-candles at the plant level. Plant species used were some of those reported as natural host plants for the six-spotted leafhopper. The cereals were planted in 3- inch pots and thinned to 5 spears per pot. Other plant species were grown in small pots and transplanted, one to a 3-inch pot, a few days before the test. Plants chosen for the feeding test were the same height and had comparatively the same leaf area. This meant that some of the weed and vegetable species were a month old, and the cereals were about a week old, when they were used. Three plant species were tested at a time, with the replicates arranged in the circular cage in the following order: ACh @ i Ba “A iCr Ae This design eliminated adjacent effects since each species was flanked by all possible combinations of the other two. The leafhoppers were swept from untreated carrots and were kept 18 hours in the growth room to acclimatize them. In the morning 100 active leafhoppers were moved into the prepared preference cage. Ten counts were made: the first in 30 minutes, 5 more counts at 30 minute intervals, and the last 4 counts at hourly intervals since the leafhoppers did not feed gt so actively in the afternoons. Immediately after a count the leafhoppers were blown from the plants so they would not remain on the same plant for the next count. shoe Results Table 1 shows the leafhopper preference for various plants, arranged in descending order. Analysis of the data was by Duncan’s multiple range test. The standard error of a mean is 6.54, and the replicates were not significantly different. TABLE 1. Mean number of six-spotted leafhopper adults feeding on various host plants. Mean number Host plant of leafhoppers per plant species? Flax, Redwood 70.3 Wheat, Lee 64.3 | Rye, Tetra Petkus 46.0 Carrot, Nantes Strong Top 35.7 Lettuce, Imperial 456 331 byt Oats, Rodney 26.3 Barley, Vantage 23.0 Dandelion, Taraxacum officinale Weber PAS Flixweed, Descurainia sophia (L.) Webb Z0 7 Prickly lettuce, Lactuca scariola L. 19.3 Curled dock, Rumex crispus L. 19.0 Aster, Improved Grego Giant 14.7 Onion, Improved Autumn Spice Sok aHach of the 3 replicates was the sum of the 10 counts made on that plant. Means paral- leled by the same vertical lines are not significantly different at the 5 per cent level. There was a preference for the cereal crops generally, and within this group are obvious selections between plants which were the same age and the same colour. Cultivated lettuce and prickly lettuce belong to the same plant species, and in a test including them the leafhoppers preferred the cultivated lettuce. In the field there is a preference for spring oats over winter wheat. At the time that migrating leafhoppers arrive in southwestern Ontario the latter crop is maturing. Lee and Robinson (1958) found higher populations of leafhoppers on lettuce than in flax in June, but in August the preference was reversed. The maturity of the crop affected the size of the population on it. The reason for leafhopper preference for certain plant species cannot be explained. It does not seem to be a function of physical characteristics such as leaf form, colour or pubescence. The insects move about for several minutes before starting to feed, and possibly are influenced by a chemo- receptor mechanism. Literature Cited KUNKEL, L. O. (1931). Studies on aster yellows in some new host plants. Contrib. Boyce Thompson Inst. 3: 85-123. Pers bh. sh wand A. G. ROBINSON (1958). Studies on the six-spotted leafhopper, anor ce fascifrons (Stal), and aster yellows in Manitoba. Canad. J. Plant Sci. WALLIS, R. L. (1962). Host plant preference of the six-spotted leafhopper, J. econ. Ent. 55: 998-999. (Accepted for Publication: February 11, 1963) 92 Additional Records of Some American Bat Flies (Diptera: Nycteribiidae) B. V. PETERSON Entomology Laboratory, Research Branch, Canada Department of Agriculture, Guelph, Ontario The following new records of nycteribiid distribution have been glean- ed from a number of bat-fly collections sent to the author since the publica- tion of his brief paper on the North American species of the family (Peter- son, 1960). Published records of Nycteribiidae from the bats occurring in North America are not numerous and these are so widely scattered through- out the literature as to be easily overlooked or not readily available. With an ever-increasing interest in the nycteribiids of North America, especially in regard to their possible role in the transmission of rabies, and with the general paucity of information on this fauna, it seems worthwhile to present these few additional distribution records. I wish to thank Dr. W. L. Jellison and Mr. G: M. Kohls, Rocky Moun- tain Laboratory, U.S. Public Health Service, Hamilton, Montana, and Mr. A. Ross, University of Arizona, Tucson, Arizona, for making their valuable collections available for my use. Basilia antrozoi (Townsend) This is probably the most common nycteribiid species collected from bats of the southwestern regions of the United States. No new state records have come to hand but numerous additional records within the known range of the species have been noted. Of these, the following one should be mentioned: Catlow Valley, Harney County, Oregon, July 19, 1937, Mr. R. L. Post, two males, from Antrozous pallidus cantwellt. Basilia antrozoi has been reported from Arizona, California, Kansas, Louisiana, New Mexico, Oklahoma, Oregon, Texas, Utah, and from Mexico. Basilia corynorhini (Ferris) Recently acquired collections of this rare species have provided two new state records. Seven males and two females were collected by Dr. D. G. Constantine from Higby Cave, 25-30 miles southeast of Boise, Ada County, Idaho, November 30, 1941, from ten bats of the genus Corynorhinus (—Plecotus). This is the third largest collection of males of this species I have seen and the record represents a considerable extension northward of its known range. One male and one female were collected by a Mr. Bordenave from a Corynorhinus bat at Albuquerque, Bernalillo County, New Mexico, February 2, 1946. This species has previously been recorded from Arizona, California, Oklahoma, Texas and Utah. Basilia forcipata Ferris Specimens of Basilia forcipata from Idaho and Nevada apparently provide the first records of the species from these two states. One female was collected from a colony of Myotis yumanensis sociabilis in a building at Hope, Bonner County, Idaho, July 28, 1940, by Dr. C. B. Philip. Several specimens were taken from Myotis yuwmanensis yumanensis at a bat cave on the east shore of Pyramid Lake, Washoe County, Nevada, May 12, 1940. A female labeled ‘““Nevada” is also at hand. The following collections supplement the few records of this species from northwestern United States and British Columbia:— Montana: Hamilton, Ravalli County, August, 1938, Dr. W. L. Jellison, from bat, one Proc. Entomol. Soc. Ont. 93 (1962) 1963 93 female; same locality, June 21, 1948, 10 specimens from 15 bats; bat in- fested cabin, Flathead County, September 3, 19438, Dr. W. L. Jellison, one male. Oregon: Malheur Lake, Harney County, August 22, 1936, Mr. R. L. Post, three specimens from Myotis yumanensis sociabilis. Washington: Lenore Lake, Grant County, August 14, 1940, Mr. H. Broadbrooks, two males and one female, from Myotis lucifugus carissima; Washington, 1950, Dr. M. Johnson, cone male, from Myotis sp.; Thurston County, June 20, 1952, Dr. M. Johnson, one female, from Myotis californicus. British Columbia: Okanagan, August 31, 1951, Dr. M. Johnson, one female from Myotis yumanensis. Published records include localities in Arizona, California, Colorado, Louisiana, Montana, New Mexico, Oregon, Utah, Washington, British Columbia, and Mexico. Basilia rondanii Guimaraes and D’Andretta In the United States Basilia rondaniwi has been known only from one male and one female (paratypes) from Shumla, Texas. A third specimen from the United States has now been identified. This is a female collected from a bat colony in a railroad tunnel, near Shumla, Val Verde County, Texas, on September 18, 1940, by Dr. W. L. Jellison and Mr. G. M. Kohls, and originally determined by Dr. Curran as B. forcipata. Two additional collections of this species were recently received, both of which represent new Mexican state records, and new host records. The collections are as follows:— Eight males and eight females from eight miles east of San Blas, Nayarit, August 23, 1960, Dr. A. Gardner, from Myotis fortidens; and three males and three females from five miles southeast of Armeria, Colima, from Sturnira liltum parvidens. Basilia boardmani Rozeboom This is an eastern species, and to the author’s knowledge, has been reported only from Florida, Georgia and Illinois. Literature Cited PETERSON, B. V. (1960). New distribution and host records for bat flies, and a key | to the North American species ef Basilia Ribeiro (Diptera: Nycteribiidae). Proce. Entomol. Soe. Ont. 90 (1959): 30-37. (Accepted for Publication: May 1, 1963) O Two New Species of Ontario Black Flies (Diptera: Simuliidae)’ D. M. Woop Department of Biology, McMaster University, Hamilton, Ontario The two species described in this paper were discovered during a con- tinuing study of the simuliid fauna of Ontario. The type locality of both species is a small roadside rivulet draining a cedar swamp and flowing through an open field at the Gryffin Sideroad and Highway No. 11, 3 miles south of Huntsville, Ontario. 1The author was the peepee of scholarships from McMaster University and the National Research Council of Canada Proc. Entomol. Soc. Ont. 93 (1962) 1963 94 Cnephia abditoides, new species Female. A small to medium-sized, black species with thin grayish-black pollen and sparse, dull yellowish-brown hair. Posterior surface of head, frons and clypeus grayish-black, subshining with thin, gray pollen. Hair sparse, recumbent, yellowish-brown on frons, somewhat erect and directed medially on clypeus. Clypeus only slightly higher than broad. Frons wide, V-shaped, at its narrowest point one-fifth the width of the head. Antenna black with paler grayish pubescence. Scape and pedicel slightly paler with short, dark hair. Palpus black with dark hair. Sensory vesicle of third segment about one-quarter of the length of the segment. Mouthparts fully developed for bloodsucking. Scutum black with thin grayish pollen and sparse, recumbent yellowish hair. Scutellum relatively bare with a few, erect hairs. Pleuron black, thinly gray pollinose. Precoxal bridge present. Mesepimeral tuft with mixed pale and dark hair. Pronotum and proepisternum with erect pale hair. Costa, stem vein, dorsal surface of radius and ventral surface of subcosta and radial sector with fine dark hair; spinules entirely absent. Radial sector unforked. Legs dark grayish-brown with dull yellow hair darkening to brown on the apices of femora and tibiae, and on the tarsi. Calcipala minute, pedisulcus nearly absent. Claw with small basal tooth (Fig. 2). Abdomen grayish-brown; tergites slightly darker with thin grayish pollen, Hair sparse, short and recumbent, mixed pale and dark. Basal fringe short, pale and relatively sparse. Genitalia as in Fig. 1. Eggs mature in newly emerged females. Male. Clypeus black with long, reclinate black hair. Antenna black with pale pubescence and a few dark hairs on scape and pedicel. Palpus black with dark hair. Scutum black, thinly gray pollinose, subshining, with sparse brown hair. Scutellum with sparse, erect black hair. Pleuron black, thinly gray pollinose. Mesepimeral tuft and hair on pronotum and proepisternum brown. Legs dark grayish-brown with dark hair, somewhat long and shaggy along dorsal edges of femora. Abdomen black, thinly pollinose, with sparse, long dark brown hair. Genitalia as in Fig. 3. Dististyle evenly tapering, with two small, stout, medially directed, apical spines. Ventral plate quadrate with deep, rounded median ventral keel. Paramere small, triangular, without arm or other associated spines. Pupa. Respiratory organ about two-thirds the length of the pupa, consisting of about 25 slender, thread-like filaments arranged in four short-petiolate groups. Ventral group with nine or ten filaments; each remaining group (dorsal, lateral and medial) with four or five (exceptionally three to seven) filaments usually arising together from the apex of their petiole. Posteriorly directed spines absent on anterior border of abdominal tergites. Anteriorly directed hooks on posterior borders of tergites long and slender, present on segments 2 to 8 (4 pairs on tergites 3 and 4, with fewer spines on tergites 2 and 5-8). Terminal segment with a dorsal pair of long, stout hooks. Cocoon reduced to a few loose threads. Holotype. Female, reared from a pupa collected May 9, 1962, from a small, roadside ditch three miles south of Huntsville, Muskoka Dist., Ontario, D. M. Wood. No. 8195 in Canadian National Collection, Ottawa. 95 Allotype. Male, same data as holotype. Paratypes. Five females, same data as holotype. One male, May 12, 1960, otherwise same data. Deposited in Canadian National Collection and U.S. National Museum. Comments. A male of this species (the paratype mentioned above) was unfortunately selected by Davies, Peterson and Wood (1962) for the illustration (Fig. 59) of the genitalia of Cnephia abdita Peterson. Refer- ences made by these authors (page 97) to the occurrence of abdita in small, warm streams flowing through open fields also applies to abditoides. The male genitalia of abditoides are larger and more heavily sclerotized than those of abdita, but diagnostic features have not yet been found, and males may best be separated by the colour of the hair of the scutum, which is brown in abditoides, whitish in abdita. The female of abditoides may be separated by the smaller, rounded (in anterior view) frons and smaller basal tooth on the tarsal claw. The respiratory organ of the pupa of abditoides has a larger number of filaments, the ventral petiole having nine or ten filaments, instead of four or five as in abdita. Simulium anatinum, new species Simulium (Husimulium) ‘H’’, Bennett, 1960, Canad. J. Zool. 38:379 (female bloodsucking habits). Female. A small gray species with white hair and gray legs similar to S. innocens (Shewell) from which it may be separated by the wider frons. Posterior surface of head, frons and clypeus, gray pollinose with whitish hair, that on frons and clypeus proclinate and recumbent. Frons about one-eighth the width of the head. Antenna dark gray with pale pubescence; scape and pedicel paler with pale hair. Palpus gray pollinose with whitish hair; length of sensory vesicle of third segment about one- fourth the length of the segment. Scutum gray pollinose with recumbent white hair. Scutellum with long, somewhat recumbent, medially directed white hair mixed with a few darker hairs. Pleuron and postscutellum gray pollinose, concolorous with scutum. Pleural tuft and hair on pronotum and proepisternum white. Postscutellum and katepisternum bare. Precoxal bridge present. Cesta, stem vein, dorsal surface of radius and ventral surface of subcosta and radial sector with dark hair, a few white hairs at the base of the costa and on the stem vein. Fore coxa gray pollinose, concolorous with pleuron. Legs grayish-brown, paler in teneral specimens. Tibiae and tarsi dark brown; with white hair basally and brown hair on the tarsi. Calcipala:minute, pedisulcus shallow. Claw with large, thumb-like basal lobe. Abdomen gray, paler ventrally with long, dense, white hair on top and sides, sparser and shorter ventrally; last three to four segments with a few long, dark hairs dorsally. Genitalia as in Fig. 4. Arms of genital fork moderately slender; terminal plates with infolded posterior margin, ap- pearing as a sclerotized edge in ventral view, the anteriorly-directed apodeme minute or absent. Male. Clypeus grayish-black, with sparse gray pollen and dark reclinate os elas dark gray with pale pubescence. Palpus grayish-black with ark hair. 96 Scutum dark brown with a slight, grayish pollinosity in anterior view and moderately sparse recumbent hair, brownish medially (yellowish in some specimens) changing to yellow laterally, paler at the humeral angles. Scutellum with erect dark hair. Pleuron grayish-black with gray pollen. Mesepimeral tuft and hair on pronotum and proepisternum brown. Legs dark with brown hair (sometimes with a few pale hairs). _ Abdomen dull, dark brown with sparse brown hair dorsally and longer, denser hair laterally. Genitalia as in Fig. 5. Pupa. Respiratory organ slightly longer than pupa, consisting of twelve long, slender filaments arranged in four groups, two dorsal petiolate groups of three filaments each, branching almost at right angles to the two ventral petiolate groups, also each with 3 filaments. Cocoon fragile, slipper- shaped, with long anterior median process, its edges somewhat thickened. Holotype. Female, reared from a pupa collected May 15, 1962 from a small roadside ditch three miles south of Huntsville, Muskoka Dist., Ontario, D. M. Wood. No. 8196 in the Canadian National Collection, Ottawa. Allotype. Male, May 9, 1962, otherwise same data. Paratypes. Four males, two females, same data as allotype. One female, same data as holotype. One male, ten females, May 12, 1960, same data as holotype. One male, May 13, 1960, small roadside ditch near Mile 30.5, Highway No. 60, Algonquin Park, Ont. Three females, May 22, 1961, roadside ditch 9 miles east of Kaladar, Ont. Deposited in Canadian National Collection, U.S. National Museum and McMaster University. Comments. This species was included under -S. congareenarum-(D. & S.) by Davies, Peterson and Wood (1962) because of the presence of twelve filaments in the pupal respiratory organ, although some differences between the two were realized. Couplet 9 of their key to the females may be amended as follows: 9. Head relatively smali, its width to that of the thorax (at the humeral angles, 1 to 1.2; the U-shaped area enclosed by arms of genital fork - wider than long; cercus longer than high ...............0.....0..000... anatinum Head width to that of thorax 1 to 1.1; the U-shaped area enclosed by arms of genital fork as long as, or longer than wide; cercus higher Pen Tamar TN Ore: hart oes Ci in tye hee Ce een ayer ae excisum D., P. & W. Males run to S. innocens (Shewell) in their key to the males, page 89, from which they may be separated by the longer parameral spines, which are as long as, or longer than, the distance from the tip of the basal arm of the ventral plate to the point of its attachment to the paramere (the parameral spines of innocens are about three-quarters this distance). Acknowledgements The author is indebted to Mr. G. E. Shewell, Canada Department of Agriculture, Ottawa and to Dr. G. F. Bennett, Ontario Research Founda- tion, Toronto, for the loan of specimens and to Dr. D. M. Davies, Mrs. H. Gyork6s and Miss G. C. Taylor, McMaster University, for help and advice. Literature Cited DAviges, D. M., PETERSON, B. V. and Woop, D. M. (1962). The black flies (Diptera: Simuliidae) of Ontario. Part I. Adult identification and distribution with descrip- tions of six new species. Proc. Entomol. Soc. Ont., 92:71-154. Bie ee} O.1 mm. x wr AM \\ zy xn 4) \ Ys) SAIN 4 Sts ANS) Se — es v/ i] 3 -—i 0.0lmm ¢ 4 ne i i : Sen. ee - Sf, ]. i / | Ay h | 7 Uf J é ARN Wi, ( if } / Wudleeeeee Pek ~ vi FR i Fic. 1. Female genitalia of Cnephia abditoides (ventral view) Fic. 2. Metatarsal claw of C. abditoides Fic. 3. Male genitalia of C. abditoides Fic. 4. Female genitalia of Simuliwm anatinum Fig. 5. Male genitalia of S. anatinum (Accepted for Publication: May 8, 1963) 98 The Black Flies (Diptera: Simuliidae) of Ontario. Part II. Larval Identification, With Descriptions and Illustrations’ | D. M. Woop Department of Biology, McMaster University, Hamilton, Ontario B. V. PETERSON Entomology Laboratory, Research Branch, Canada Department of Agriculture, Guelph, Ontario D. M. DAVIES Department of Biology, McMaster University, Hamilton, Ontario HELEN GYORKOS Department of Biology, McMaster University, Hamilton, Ontario Introduction This paper is concerned with the identification of the last stage larvae of the Ontario species of black flies. Part 1 of this study considered the general ecology of the immature and adult stages, the bloodsucking activity of the females and the identification of the adult and pupal stages (Davies, Peterson and Wood, 1962). Since Part I was published, Wood (1963) described two new Ontario species, namely, Cnephia abditoides and Simulium anatinum. Definitive works on the larval stages of North American species are few (Vargas, Palacios and Najera, 1946; Sommerman, 1953; Stone and Jamnback, 1955), although early keys were presented by Johannsen (1903, 1934). A number of authors have described or commented on larval forms but usually in connection with descriptions of new species. Descriptions of the black-fly larvae of Europe and Asia have bese given by Edwards (1920), Puri (1925), Smart (1944), Dorier (1945), Grenier (1953), and Rubtzov (1956, 1959-1962) ; for Africa by Crosskey (1960) ; for the Australian region by Tonnoir (1925) and Mackerras and Mackerras (1948, 1949, 1950, 1952) ; for Java and Sumatra by Edwards (1984) ; and for Guatemala by Dalmat (1955). In many cases, especially when initiating control measures, the larval stage is the one most commonly collected; hence, the importance of provid- ing keys and descriptions of black-fly larvae. In addition, although pupae may also be present in the stream at the same time, some species are much more readily distinguished by their larvae. Moreover, a thorough under- standing of the larvae is proving of great value in appreciating the phylo- geny of the family. Morphological Characters Used in This Study of Black-Fly Larvae Labrum A characteristic feature of most black-fly larvae is the pair of promi- nent mouth fans or head fans, on either side of the anterior end of the head, for straining food particles from the water flowing past. The stalk of the fan is a tubular outgrowth, and is derived from the lateral wall of the labrum (Puri, 1925). The dorsal half of the stalk is a rigid, slightly convex plate; its ventral wall is mostly membranous and flexible, containing mid- 1Grants were supplied to D. M. Davies by the National Research Council of Canada. The senior author was the recipient of scholarships from McMaster University and the National Research Council of Canada. Proc. Entomol. Soc, Ont. 93 (1962) 1963 99 ventrally a longitudinal rod which is probably homologous with the torma of the mosquito larva (Snodgrass, 1959). The torma expands distally into a rounded tip, the connective sclerite (Fig. 14). The long, flattened, slender rays of the head fan are each attached along one edge at their bases to the end of the stalk between the dorsal wall and the ventral connective sclerite, and are directed ventrally. | The head fans are evidently extended by internal fluid pressure (mechanical pressure on the larva will produce this effect) ; there is no evidence of a muscle for this purpose. Folding is accomplished by a longi- tudinal postero-mesad movement of the torma in relation to the dorsal wall, whose distal edge serves as the fulcrum. The torma is moved in this way by a single large muscle inserted on a slender, transparent, tendon-like apodeme attached to the antero-medial corner of the torma (Fig. 14). In one Ontario species, Twinnia tibblest Stone and Jamnback, the head fans are absent in all larval instars. The secondary fan rays of the simuliid head fan are actually a continuation of the primary rays and are separated from them by a few short, blunt, aborted rays. They arise in a nearly straight row along the posterior edge of the connective sclerite, and are not appreciably dif- ferent in structure from the primary fan rays (Figs. 14, 15). Each ray is flattened, and bears a single row of hairs along the edge facing the connective sclerite. These hairs are much longer than those on the primary rays. The arrangement of the secondary rays has been shown to be of two types (Sommerman, 1953). The fundamental difference between the two types is that one contains many more rays in a slightly longer row, and when the entire head fan is extended, these secondary rays open in two different ways, forming two distinct patterns. The simpler pattern is found in Prosimulium spp. in which the flattened secondary rays are - erected to form a small, flat, triangular fan projecting ventrally, perpen- dicular to the primary fan (Fig. 14). The hairs along the morphologically anterior edge of each ray now extend laterally because each ray is oriented with its flattened sides facing antero-posteriorly. Another peculiarity of the head fans of Prosimulium spp. is the presence of many fine hairs attached to and around the edge of the connective sclerite, at the bases of the ~ primary fan rays. The second, more complex type of head fan, found in Cnephia and Simulium, is composed of many more secondary rays, although they are still attached in a straight row, forming a small cupped fan, inside and below the primary fan (Fig. 15). The small fine hairs on the connective sclerite and around the bases of the primary rays are absent. Antenna The antenna of the larva appears to be basically composed of four segments. In nearly every species, the basal two segments are separated by a weak, sometimes incomplete, crease. The second segment is, in some species, further subdivided into two to seven secondary annuli, each separ- ated from one another by a similar weak crease distinguished by a non- pigmented band (Fig. 37). The third, or penultimate, segment is completely sclerotized and is usually narrower than the basal two segments from which it is distinctly separated by a flexible joint which bears two minute, ~ conical papillae. A small, conical tip forms the apical segment. The ratios of the lengths of the various segments and annuli to one another, and the number of annuli are of diagnostic value. 100 Hypostomvum The hypostomium is the antero-medial region of the ventral wall of the head capsule. It is double walled, being a flattened, wedge-shaped anterior extension of the ventral edge of the head capsule. The fold (labio- hypostomial fold—Fig. 16) where the dorsal wall of the hypostomium turns forward to become the membranous connection to the venter of the labium, is visible through the semi-transparent ventral wall of the hypostomium, as a semi-circular line. The position of this line often changes after fixation and is unreliable taxonomically. , The anterior edge of the hypostomium is produced into a row of heavily sclerotized, sharp points, the hypostomial teeth, that are of great value in determining species. Basically these teeth are arranged in three groups. The central group, with one long median tooth and two smaller ones flanking it, is usually slightly inclined dorsally. Each lateral group contains about five teeth of variable length. In Prosimulium all lateral teeth except the outer- most one are here termed sublateral teeth. The lateral teeth are not as strongly tilted dorsally as are the central teeth. In some species groups, the lateral teeth are borne on pointed or rounded lobes flanking and extending well beyond the central teeth (Figs. 25, 30). The size and shape of these lobes are diagnostic. The teeth are generally believed to serve as a scraper for removing food or detritus from the substrate, but may also provide a serrated edge for cutting the secreted ‘silk’ strand. In this respect, the labio-hypo- pharyngeal complex which bears the common opening of the salivary glands, is grooved to slide forward and backward over these teeth. The labio-hypopharyngeal complex may be extended by internal pressure while silk is being expressed, and then retracted, drawing the orifice of the salivary glands over the teeth. Postgenal Cleft On the ventral surface of the head, the point of union of the postgenae is usually partly unsclerotized, leaving a rounded or inverted V-shaped cleft which appears to be a ventral extension of the occipital foramen. This cleft has been variously called the “throat cleft’, “gular cleft’, “epicranial cleft’ and “‘postgenal cleft’? (the last term is here used) and its shape is of the utmost value in characterizing species. Pattern of Head Spots Another feature which is of taxonomic value is the head pattern. It is formed by the differential deposition of pigment, both at the sites of muscle origin and in the surrounding areas. Usually the positions of muscle origin are relatively constant and thus pigment associated with them forms a pattern which differs among different species. The components of this pattern most used are the origins of the labral and pharyngeal muscles on the cephalic apotome (Fig. 16). Nomenclature of the head spots has been modified from Stone and Jamnback (1955) and Crosskey (1960). The labral muscles are of two pairs. One pair, inserted on the epipharyngeal apparatus, originates on the mid-line, the associated pigment forming the antero-median spot. Each muscle of the other pair, which is inserted on the torma of the head fan, is divided into two portions with two origins. The associated pigment forms the postero-median spot and the second postero-lateral spot. The three remaining pairs of spots, the first and second antero-lateral spots and the first postero-lateral spot are formed by the pigmented origins of the 101 dorsal pharyngeal muscles. The first and second antero-lateral spots may be close together appearing as a single spot (Figs. 46, 49), and their positions relative to one another are diagnostic. The first postero-lateral esat may be pale and indistinct, or may be so close to the second that the two appear as one. Lateral to the cephalic apotome are the origins of the mandibular and maxillary muscles and the ventral pharyngeal muscles, while on either side of the postgenal cleft are the crigins of the labial muscles. As diagnos- tic features, the spots formed by these muscles have not been as useful taxonomically as those on the dorsum of the head. In some species, the muscle origins are unpigmented, contrasting with the surrounding pigmented area, forming a reversed head pattern. A spot of pigment antero-ventral to the eye spots (Fig. 1) is also diagnostic for some species. Proleg On each side of the proieg, posterior to the apical ring of hooks, is a small lateral sclerite. Its shape and size is useful in separating some species. Abdomen The abdomen may gradually expand posteriorly (Fig. 3) or segments 5-8 may be abruptly enlarged (Fig. 1, 2). At the posterior end of the larva, ventral to the anal opening, is a ring of many radiating rows of minute hooks, the anal ring; the number of hooks in each row varies from species to species. Antero-ventral to this ring of hooks are, in many species, a pair of cone-shaped ventral tubercles, whose presence and degree of development are diagnostic. In some species, the two tubercles are united medially to form a single mid-ventral bulge, or the tubercles may be situated on a similar bulge. The anal sclerite, lying dorsal to the ring of hooks, is usually X-shaped, but in a few species it may be Y-shaped (Twinnia tibblesz) , subrectangular or absent. The antero-dorsal arms are usually short, extending anteriorly as part of the ventral wall of the rectum. The postero-ventral arms extend laterally along the anterior edge of the ring of hooks (Fig. 13). The com- parative lengths of these arms is useful taxonomically. The width of the sclerite at its midpoint is also diagnostic. The dorsal surface of the abdomen may be ornamented with cuticular hairs. Larval body pigment is associated with chromatophores lying near the surface and usually aggregated into patches. It is often of two colours, one colour, usually reddish, being confined to two longitudinal rows of spots or patches, the other forming a background. This background pigment may be aggregated into bands or patches giving a mottled appearance or may be generally distributed. Preparation of Material for Study To obtain the most satisfactory preservation, larvae were placed in 95% ethanol (without glycerine) immediately after collection. This treat- ment minimized distortion and colour change, and usually resulted in the extension of the head fans. For the preparation of larval drawings the mandibles, maxillae and pharyngeal region were removed in one piece by severing their cuticular attachments around the anterior edge of the head capsule. The capsule, cut from the body, was then cleared for four hours in cold 10% potassium hydroxide and washed in water where the softened contents were removed. 102 sf ue 9) = aaa, It was then transferred to a glass depression slide into a drop of water and glycerine. Study was completed after the water had evaporated. Drawings were made with the aid of a Bausch and Lomb ‘Speed Matic” micro- projector (Cat. No. 42-63-56-48) with a carbon are light source. Stability of orientation in glycerine was obtained by attaching the specimen to a small amount of petroleum jelly. Key to the Larvae of Ontario Simuliidae* 1. Head fans absent (Fig. 21); anal sclerite Y-shaped...............000...... Twinnia tibblesi Head fans present; anal sclerite X-shaped, subrectangular or absent........................ 2 2. Anal sclerite absent (or unsclerotized): lateral margins of abdominal segment 5 projecting ventrally far beyond central portion of same segment and of segment 4 (Fig. 2); anterior margin of hypostomium concave, with small indistinct teeth - PT Se Sy) Wee es Ira) eA a ONO ance ge eR eli eg SOUR Cnephia invenusta Anal sclerite present; lateral margins of abdominal segment 5 not projecting ventrally; hypostomium variable, usually with conspicuous teeth......0.00000.00..0..00.... a 3. Basal two segments of antenna colourless, distal two segments darkly pigmented; postocciput nearly complete dorsally, enclosing cervical sclerites (Fig. 16); secondary fan with few rays, when open forming a flat triangular fan (Fig. 14) MAGUS A OSLTIPULLUOU INO) age cet hos ose ne aCe Res Preheat RE re Ee Ge a WME Mialer caere 4 Basal two segments of antenna at least partly coloured, distal two segments rarely of a contrasting dark colour; postocciput with a wide gap dorsally, not enclosing cervical sclerites (Figs. 27-60) (except C. abdita and C. abditoides); secondary fan with many rays, when open forming a cupped fan (Fig. 15).......00000.00...00000000.. aa 4. Anal sclerite subrectangular (Fig. 12), antero-dorsal and postero-ventral arms at most only weakly developed; rectal scales absent; lateral plate of proleg narrow, Maincompat lelito bases col-apical hooks...) 5.5.0) i asec tes tee dese ea ae ae 5 Anal sclerite X-shaped (Fig. 13), both antero-dorsal and postero-ventral arms well developed; rectal scales present; lateral plate of proleg not as above (except DORE OUTED ak SIRES Se AGE Gt ae eB gt Dean er kt ett SiR cr eR nie Sere Maen de. 5 6 5. Outer lateral teeth of hypostomium agnnen eran longer than other teeth, median tooth slightly longer than sublateral teeth; head fan with about 45, or fewer, TORS CCP TGS 5 TNS ALE) Nak ES ne a ee ae een en neti 1h a a P. decemarticulatum Outer lateral and sublateral hypostomial teeth equal in length, median tooth generally shorter but not exceeding length of lateral or sublateral teeth; head fan abeADOUL, NOLO more, rays (ligs. 10,°23)2 008 eo a Be eae P. gibsont 6. Lateral plate of proleg narrow, lying parallel to bases of apical hooks; median tooth of hypostomium conspicuously shorter than lateral teeth; postgenal cleft short and narrow, extending at most one-sixth the distance to tips of hypostomial teeth, rounded apically with light sclerotization continuing around apical margin (Figs. io. Fane ek iN ABN sts ae RR Se ct Et 2 el ee Oe. a heen SNe P. vernale Lateral plate of proleg broadly L-shaped to almost triangular; median tooth of hypostomium at least as long as the lateral teeth; postgenal cleft longer and wider, extending one-fifth or more the distance to tips of hypostomial teeth, Selerobtvation. not, continuine around apical (mareine: 3 oe.) ks ee 7 The Median tooth of hypostomium the longest (Figs. 7-8), the lateral teeth subequal in length or decreasing in length outwardly; maxillary palp about twice as long as width at base; anal ring with about 14 hooks in 85-95 rows; abdomen gradually expanding posteriorly (CR) is ah: Peete CRUE ee eR Le RAR 0! MM em RNS oT 8 Median tooth of hypostomium, at most, about as long as longest lateral teeth (Figs 4-6), the lateral teeth not decreasing in length outwardly; maxillary palp two and one-half to three times as long as width at base; anal ring with 9- Pe hooks in about 65-75 rows; abdomen abruptly exanding at segment 5 (Fig. 1)...... 8. Tips of secondary projections of median tooth about equal in length to tips = outer lateral teeth but shorter than tips of longest sublateral teeth (Fig. 7); vertical sclerotization of lateral plate of proleg heavy, well developed, extending basally more than one-half the length of apical segment of proleg; head capsule dark brown (Fig. 19); body rather uniformly brownish- -gray with narrow, pale, AML CRSe oMMen bal mDAMGS,. 65 te, ted e, Wes rahn Rote aes cas Odea, ee, sucks Head P. magnum Tips of secondary projections of median tooth at least as long as tips of longest lateral teeth (Fig. 8); vertical sclerotization of lateral plate of proleg light, not well developed, usually extending basally much less than one-half the length of *The larva of Cnephia ornithophilia Davies, Peterson and Wood is not known. 103 10. tf: 12. 13. 14. 15. 16. Li: 18. 19. apical segment of proleg; head capsule pale yellow to brownish-yellow (Fig. 20) ; body pale whitish-gray to gray, darker dorsally, with rather broad, pale, inter- sepmental ‘bandss (28200. S3-5u..) oe aero eee gh eae P. multidentatum Outer lateral teeth of hypostomium distinctly longer than sublateral teeth which are of equal length (Fig. 4); antero-dorsal arms of anal sclerite each with a postero-medially directed apodeme, these arms longer than postero-ventral arms (Fig. 13); head capsule medium brown (Fig. 17) ; body light brown....P. fontanum Lateral teeth of hypostomium of equal length or decreasing in length inwardly; length of arms of anal sclerite variable, but antero-dorsal arms without apodemes; head capsule and body colour variable) o 5 LS eee 10 Lateral teeth of hypostomium decreasing in length inwardly (Fig. 5); antero- dorsal arms of anal sclerite shorter than postero-ventral arms, or arms subequal; A large grayish-brown species with a pale brown head capsule; first postero- lateral head spot usually present; antero-lateral head spots relatively small GRig 1G) eee Pee eC tee berg ge Pe MICE een ere Age P. fuscum Lateral teeth of hypostomium usually of equal length (Fig. 6), occasionally decreasing in length inwardly; antero-dorsal arms of anal sclerite considerably longer than postero-ventral arms; a smaller brown species with dark brown head capsule; first postero-lateral head spot usually absent; antero-lateral head spots relatively large. (Fig: 18)s0 7 c> peo ee ye ee P. mixtum Abdomen with a single ventral transverse bulge on segment 8; postgenal cleft narrow and shallow, of an acutely pointed, inverted V-shape (Genus Cnephia, 14 sg 020 eee ge SR hee: a rriet er Ee MeN MLA MGT e TT ee 12 Abdomen without a ventral transverse bulge on segment 8, but may have two ventral tubercles; postgenal cleft wider and deeper (if small, then squared)........ 13 Head capsule with distinct, brown spots on cephalic apotome and posterior region of gena; entire margin of postgenal cleft narrowly pigmented; hypostomial teeth darkly pigmented; distal two segments of antenna darker than basal two; eye spots of normal. size. (PISS 22 Re ee oe C. mutata Head capsule with indistinct, brown spots on cephalic apotome, gena without spots; postgenal cleft pigmented on lateral margins only; hypostomial teeth pale, weakly sclerotized; antennal segments uniformly pale; eye spots reduced (Fig. 20) eae ora dee ook oeR ASE Gs Gene RE OR GE en oR ai att a he ae C. emergens Hypostomium with minute lateral teeth borne on two large, nearly parallel-sided lobes, these lobes much longer than the median tooth, their length one and one-half or more times their width at base (Fig. 25) (Genus Cnephia, in part).................... 14 Hypostomium with longer lateral teeth, not on large lobes, which are at most only slightly longerthan median tooth (P1g¢s..33-35) 37 eo -16 Third segment of antenna with irregular, sclerotized bands alternating with membranous areas along its entire length, this segment longer than basal two seements combined’. .....0 82.55 s... 2k 2S 2 ee oa ee ee ee 15 Third segment of antenna darkly pigmented, without irregular, sclerotized bands, this segment shorter than basal two segments combined (Fig. 30)........ C. denaria First segment of antenna twice as long as second segment; head capsule almost colourless, head pattern pale and indistinct (Fig. 25) ..........000000ce C. abdita First segment of antenna three times as long as second segment; head capsule darker, head pattern, dark and distinct<(Mic- (26) 2.) 3a C. abditoides Abdomen (segment 8) with two large ventrai tubercles, one-third to one-half the depth of the abdomen below their points of attachment; antenna usually noticeably longer than stalk of head fan; postgenal cleft not pointed apically, may be short, or long and bulbous; suboesophageal ganglion and epidermis in postgenal cleft not distinctly blackish (Genus Simulium, in part) |.) oni. £7, Abdomen without ventral tubercles, or these inconspicuous and reduced to less than one-sixth the depth of the abdomen below their points of attachment; length of antenna variable; postgenal cleft pointed apically, or long and bulbous or sub- quadrate; suboesophageal ganglion and/or epidermis in postgenal cleft often distinctly blackish (Genus Simuliwm, in part)... See 33 Second segment of antenna subdivided into four or more annuli, the divisions usually ‘marked ‘by white 1s”) -2e. ee ee aot her 18 Second segment of antenna not subdivided into annulli............00000000000c ee 23 Second antennal segment subdivided into five or more secondary annuli................ 19 Second antennal segment subdivided into four secondary annuli.............................. 20 Antenna darkly pigmented, contrasting with adjacent stalk of head fan (Fig. 37) scadavacvadearelestunacdeallasicsetes dab PehCbe Wrote. bata aas cs laes, cieUa Rat ie ee Che seen eer mee pA kanee eeae S. baffinense Antenna moderately pigmented, not contrastingly dark with adjacent stalk of head fan (Pig. :34) occ eR a ess ica ce S. anatinum 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. d2. Median hypostomial tooth shorter than longest lateral teeth; postgenal cleft short and narrow, its width one-sixth or less the width of the head a alt shah bas SM nee Ze Median hypostomial tooth longer than lateral teeth; postgenal cleft wider, being one-fifth or more the width of the head 22. Postgenal cleft with a V-shaped anterior margin; dorsal head spots dark brown (Fig. 33); abdomen without two clearly defined longitudinal rows of reddish ROLL SIROLOMES EULER donc coke a uit Ml eee na Ue wane La i aad ne gamete or mer ME ae 2, S. innocens Postgenal cleft square; anterior margin not V- shaped; dorsal head spots pale brown (Fig. 32) ; abdomen with two clearly defined longitudinal rows of reddish SOUS CORSE Re Mee St ruben. oi, nul, So) Degas Be apne, Miner eeepc tebe (eRe a S. congareenarum Dorsal head spots brown on an almost transparent background CBs 40): Ghee canens grat elietsn debe: NR Tee NE Ree Mina tae eM RA Ty Sa mnmE am Mie AS ann AGL cdRmn es ee Mra Gy S. emarginatum Dorsal head spots enclosed in a dark pigmented area (Fig. 39)..S. euryadminiculum Postgenal cleft small, usually square, with a straight, or broadly V-shaped anterior border (rarely slightly rounded), its length (from posterior tentorial pit to anterior margin of cleft) one-fifth or less the length of the head between posterior tentorial PLEA al POStOMMal Geeta: lank mal a NG Seen | ed Ne Ter eo cele es ae aige 24 Postgenal cleft larger, one-third or more the length of the head between posterior tentorial pit and hypostomial teeth, with rounded apex, usually broadest at about GhHemiMIGe DONG: Of ILS Menon Sn a ee ND Ve ene Cl es Mea ogee tea 27 Median hypostomial tooth equal to, or shorter than longest lateral tooth; body pigment unicolorous, either green or reddish-brown; antero-lateral head spots not Closely approximated to one*another (Figs:,35; 36) 02.0 2..bcccc stk to sdeveees esupsvseoeeows 25 Median hypostomia! tooth longer than lateral teeth; body pigment of two contrast- ing colours, reddish-brown with greenish-gray or pale orange-brown 6 Second antero-lateral head spot almost directly behind first antero-lateral spot; median hypostomial tooth shorter than longest lateral teeth (Fig. 35); body pigment greenish; antenna somewhat darkened...............0...0000cceceee S. rivula Second antero-lateral head spot somewhat lateral to, i.e., not directly behind first antero-lateral spot; median hypostomial tooth about equal in length to longest lateral tooth (Fig. 36); body pigment reddish or pinkish-brown; antenna pale soos oe oge Egan ee ea SNARES per tral: Hen ee AL Se IRA OEE MEETUP ena A S. excisum Second antero-lateral, postero-median, and postero-lateral head spots enclosed in a darkly pigmented area (Fig. 47); antero-lateral head spots not closely approximated; body pigment orange-brown with two longitudinal rows of oval, ECORI OUS ee Gece ne ON CIS By ae SNe mma Deena mask AN i al te S. aestivum Dorsal head spots not enclosed in a darkly pigmented area; antero-lateral head spots almost confluent (Fig. 46); body pigment of alternating bands of reddish- aur Pe CMIGh=OTA Vi. cui 2 sete ro ilk yo tehuavec Sal 1 hey Oh.. wa uci ude mr S. aureum Postgenal cleft long and bulbous, extending to, or nearly to base of hypostomium (CTE 0) a ai aaah = cea A ana cele ey eae (aaa Ate Cin Ue Mee eeaeaiee SME See cist S. rugglesi Postgenal cleft shorter, rounded apically but not bulbous, extending less than pne-holer the, distance tovbase of sy postomiumy 439225. n ie . e 28 Pigmented area antero-ventral to eye present, large...........0000occcccccccetceeeeceeeseneteeee 29 Pigmented area antero-ventral to eye absent, or very small... 30 Dorsal background pigment of head extended forward beyond bases of antennae as a dark median stripe; length of postgenal cleft one-third or more the distance from posterior tentorial pit to hypostomial teeth (Fig. 48)... S. croxtoni Dorsal background pigment not extended beyond antero-median spot; length of postgenal cleft one-quarter or less the distance from posterior tentorial pit to Hy WOSuOIIe teeth shies 24) ease ik eae aml cre I OR ta set in eee Sa S. latipes First abdominal segment with two dorsal and two ventral spots of darker, denser, greenish pigment contrasting with paler pigment on adjacent segments; head capsule pale, almost colourless on anterior half, contrastingly dark brown basally iy or i ee eR eit ONG LTS Mie. cate eine sols, gin cam S. quebecense Pigment of first abdominal segment not contrastingly darker than that of adjacent EGIMETIUS Hee te ma eer ake al Bees a rank Sone nes mens ase eenne Riek eh Sn tsa ae ata Ce eho ee eae ne 31 Toothed area of hypostomium relatively narrow, the teeth relatively uniform in size; postgenal cleft tapering apically, widest posteriorly (Fig. 41); a large overwintering species, maturing in early Spring................00cc eee. S. pugetense Toothed area of hypostomium wider, the median tooth relatively long, the two flanking pairs of teeth relatively short, the remaining lateral teeth raised; postgenal cleft widest near mid- point of its length (Figs. 48, 44); small species ARTCC MMe SUM IMGT ce ents cole ce amtt sc eeitadian Saal. Sree eared Arana, wank oe pe AE eee 32 Length of postgenal cleft one- third or more the distance from posterior tentorial pit to hypostomial teeth (Fig. 43); body pigment pale sand-brown........ S. gouldingi 105 33. 34. 35. 36. 37. 38. 39. 40. Al. 42. Length of postgenal cleft one-quarter or less the distance from posterior tentorial pit to hypostomial teeth (Fig. 44); body pigment orange-brown................ S. impar Abdomen gradually expanding posteriorly; median tooth of hypostomium extending far beyond longest lateral teeth; head capsule with a number of scattered, pale setae which are small but conspicuous; anal ring with about 125 or more rows of hooks; large, mostly black species, 10.0: mm or longer... eee 34 Abdomen abruptly expanding at segment 5, or, if gradually expanding posteriorly, median tooth of hypostomium not extending far beyond longest lateral teeth; head capsule mostly devoid of small setae; anal ring with less than 90 rows of hooks; smaller species, variable in colour, less than 9.0 mm long, or, if longer, then body pale brown Outer lateral hypostomial teeth conspicuously longer than sublateral teeth; head spots mostly pale; cephalic apotome uniformly dark; antenna dark, with three conspicuous white patches (Fig. 52); lateral plates of proleg apparently not con- nected by a ventral} sclerotized band)..5). 9.3 ee ee S. longistylatum Outer lateral and sublateral hypostomial teeth of nearly equal length; head spots mostly dark; anterior portion of cephalic apotome pale, rest dark; antenna pale, white patches not conspicuous (Fig. 51); lateral plates of proleg connected by a ventral, lightly: sclerotized band) 2. 03.)4..). S. pictipes Postgenal cleft subquadrate, apical margin straight or rounded; anal gill with three simple lobes, these occasionally with minute, secondary bumps...................... Postgenal cleft long and bulbous, or sharply pointed apically; anal gill with digitately compound lobes...) ee ee Hypostomial teeth short, not well developed; second segment of antenna nearly uniformly pale yellow, without a white band near tip; anterior margin of cephalic apotome, in lateral view, abruptly rounded antero-ventrally; antero-lateral head spots separated (Fig. 29); abdomen gradually expanding posteriorly (Fig. 3); Dale brown |SPeCleS 0222) Soran ick eee culness suutecn neht oale ius, Sle cae) or pail ee ee C. dacotensis Hypostomial teeth longer, well developed ; second segment of antenna with a whitish band near tip; anterior margin of cephalic apotome flatter, not abruptly rounded antero-ventrally; antero-lateral head spots confluent (Fig. 49); abdomen abruptly expanding at segment 5 (Fig. 1); grayish to blackish species....S. vittatwm Postgenal cleft bulbous in outiine, length, and width near middle, subequal; antenna conspicuously longer than stalk of head fan; head spots dark 8 Postgenal cleft an inverted V-shape, pointed apically, length usually greater than width; antennal length variable; head spots variable 4 Head capsule pale yellow to brownish-yellow, with light brown head spots usually surrounded by a pale but distinct fulvous area; postgenal cleft extending three- fifths or more the distance to hypostomial teeth (Fig. 55); lateral plate of proleg, at most, faintly visible; small species, 4.5-5.0 mm in length SSS ee on S. jennings Head capsule darker yellowish- brown, with dark brown head spots surrounded by, at most, a faint fulvous area; postgenal cleft extending only about one-half the distance ‘to hypostomial teeth (Fig. 56); lateral plate of proleg well developed, easily visible; slightly larger species, 5.0-6.0 mm in length................ S. fibrinflatum Postgenal cleft a narrow, straight-sided, inverted V-shape, not narrowing poster- iorly, extending about one-third the distance to hypostomial teeth; head capsule brown, with indistinct, brown head spots (Fig. 58) .................c... S. parnassum Postgenal cleft wider, a bowed, inverted V-shape, narrowing posteriorly, length variable; head capsule and head spots ‘variable 3.0 ee Antenna long, nearly entire distal two segments extending beyond apex of stalk of cephalic fan; suboesophageal ganglion or epidermis in postgenal cleft distinctly blackened; abdomen blackish 41 Antenna short, extending at most, only slightly beyond apex of stalk of cephalic fan; suboesophageal ganglion and epidermis in postgenal cleft not blackened; abdomen not. blackish 330.3. ea ee ee eee 42 Postgenal cleft with a distinct, narrow, apical extension extending almost to base of hypostomium; cephalic apotome with distinct, dark spots, posterior portion with a narrow, dark, fulvous area extending less than one-half the length of head; suboesophageal ganglion pale, epidermis in postgenal cleft blackish; head fan with about 50) rays primary fan iray S = secondary fan T= torma Fic. 16. Dorsal and ventral views of the head capsule of the larva of P. fuscum. 118 -—_———4 17 P mixtum |8 P. fontanum 19 P. multidentatum 2O P. magnum 119 iE tipblies: =) P vernale o- 22 120 Gasca 2 C.abditoides CO C.emergens C28 121 CC. dacotensis 29 CG: denoria SO C.invenusta 3] S. congareenarum 32 122 iS -immocens 3S S.anatinum 34 6 rival: 35 S. excisum 36 123 S. euryadminiculum 39 S.emarginatum 40 124 S. quebecense 42 A| pads ngi pugetense gould e s ~ S aureum form-A 46 Ss latipes 45 S 48 f croxton S: Vuln AEH aest e S 126 Sy piciipess. | S. longistylatum 52 127 S. parnassum 583 5S. fuijerosum 3a: S jennings: ° 55 S. fibrinflatum 56 128 —— 57 S. corbis 5a ———— S. decorum ——— S.venustum 59 S. verecundum 60 129 IV. THE SOCIETY PROCEEDINGS OF THE NINETY-NINTH ANNUAL MEETING ENTOMOLOGICAL SOCIETY OF ONTARIO Belleville, Ontario November 14-16, 1962 The 99th Annual Meeting of the Society was held at Belleville. The meeting ran from noon, Nov. 14 to noon, Nov. 16 an arrangement that appears to be more convenient for members travelling by ear. Sessions were held in Education Hall, Nurses’ Residence, Belleville General Hos- pital. The meeting commenced at 1:45 p.m., with the President in the chair. Members were welcomed by Dr. B. P. Bierne, Director of the Entomological Research Institute for Biological Control, under whose auspices the meeting was held. After some business announcements, the President called on Dr. H. A. U. Munro to introduce the guest speaker, Dr. C. E. Atwood, of the University of Toronto, who for the next forty-five minutes entertained members with a most enjoyable account of his recent trip to Italy pate he took part in the Conference of the International Union for the Study of Social nsects. The meeting then proceeded with submitted papers according to the printed program. A smoker was held on Nov. 14, and on the evening of Nov. 15 the Annual Banquet took place in the Quinte Hotel with well over one hundred guests present. Highlights of the Meeting were the Seminar on “How Useful is the basic research program to economic entomology”, and the four papers read by university students for the President’s Prize. The latter was won by Mr. W. Klassen, of the University of Western Ontario, for his paper on “Insecticide resistance and the genetics of Aedes aegypti L.” The following papers were presented (abstracts are included if supplied by authors and the papers were not published in the Proceedings) : DONDALE, C. D. Spider Research in Canada. As spiders are very motile, predatory animals, they have potential use in pest control. They are numerous in crop plantings and are capable of capturing a variety of insects. Also, Canadian araneologists are studying spider taxonomy, embryology and anatomy. SMITH, S. G. Cytotawanomy: The Phylogenetic Implications of Incompatibility Systems. The weevil Pissodes terminalis is unparalleled in the animal kingdom in that males are invariably heterozygous for an autosomal fusion as well as for the sex- determining chromosomes (CccXY), whereas all females are homozygous for both (CCXX). It appears that polyspermy is the rule and that “fused” (CX) and “unfused” (ccY) sperms alone function in the fertilization of CX eggs, to the exclusion of ccX and CY sperms. This autosomal dichotomy of the sexes is rigorously perpetuated in laboratory crosses of yosemite 2 (CC) by terminalis %, and in a modified form in (i) approximatus 2 (cc) x terminalis and (ii) strobi @ (cc) x terminalis %. Moreover, the original incompatibility system has been synthesized by backcrossing yosemite x strobi %, which perforce yields CX, ecX, CY, and ccY sperms, to yosemite ?, only the first and last categories of the four being functional. The reaction between the nucleus of the sperm and the cytoplasm of the egg common to these various crosses implicates introgressive hybridization in the origin of terminalis and approximatus. RUEFFEL, P. A Cytological and Biochemical Approach to the Taxonomy of Fresh- water Midges (Diptera: Chironomidae). Many of the morphological criteria used in the taxonomy of the Chironomidae larvae vary greatly depending upon the environmental conditions, and thus the taxonomy of these larvae is relatively subjective and a more 130 objective approach is desirable. Three techniques have been applied to recognize species, subspecies and hybrids of these larvae: 1) cytological examination of the band patterns of the salivary gland chromosomes, 2) electrophoretic studies of the haemolymph, and 3) immuno-electrophoretic analysis of the proteins. These techniques are suitable for identifying species in the larval and pupal stages, for analyzing the homogeneity or heterogeneity of a wild population, and for recognizing the frequency of hybridization. The present study has shown that most of the taxonomic keys established in European species cannot be readily applied for the identification of the Chironomidae on this continent. A reliable taxonomy of Chironomidae larvae appears of practical value because they are widely used in diagnosing the degree of freshwater pollution. Downe, A. HE. R. and West, A. S. The Serological Specificity of Haemolymph Antigens in Various Stages of Insect Development. Precipitin-test comparisons were performed with nymphal and adult haemolymph antigens of three species of roaches (Blattella germanica (L.), Periplaneta americana (L.) and Blaberus giganteus (L.)). The results of photronreflectometer tests with antisera prepared against adult antigens and fourth-stage nymphal antigens are described in detail. The most specific serological reactions were those involving adult antigens. Absorption of anti-adult serum with nymphal antigens greatly reduced or entirely eliminated heterogolous reactions. Such a pronounced reduction of heterologous reactions was not observed when anti-nymph serum was absorbed with adult antigens. Gel-diffusion studies indicated that adult haemolymph possesses a greater number of “discreet” antigens than nymphal haemolymph. The least-specific antigens in adult haemolymph were those which were also shown to be present in nymphal stages. MuscrRAVE, A. J., GRINYER, I., and HOMAN, R. Some aspects of the fine structure of the Mycetomes and Mycetomal Micro-Organisms in Sitophilus (Coleoptera: Curculioni- dae). Certain elongate elements that occur in the cells (mycetocytes) of special struc- tures (mycetomes) in the larvae of granary and rice weevils (Sitophilus granarius (L.) and Sitophilus oryza (L.)) have long been regarded as micro-organisms. There is some evidence that they are of benefit to the insect host though they are not, apparently, essential to it. These elongate elements occur in the gonads of adult female and the guts of adult male and female weevils. The elements have resisted culture outside the insect and their exact biological status has been open to doubt. Some recent studies that have incorporated the use of the electron microscope have added considerable evidence to the concept that the elements are indeed micro-organisms. WELCH, H. E. A Survey of Mermithid Parasites of Black Flies. Mermithids are common parasites of the aquatic and adult stages of black flies. The life history of the nematode is well synchronized with that of the host, and so adapted that the mermithid population is maintained in the breeding area of the black flies despite the constant downstream movement of the water. A preliminary survey was made to determine both the geographical range of the mermithid parasites and the changes with time in the rate of parasitism at a given locality. This survey will be useful in the possible introduction of mermithids from Europe or North America into areas where they do not normally occur. BRIAND, L. J. and WELCH, H. E. Use of Rhabditoid Nematode, DD136, for Control of Mosquitoes. Laboratory and field trials showed that mosquito larvae could be infected and killed by the nematode, DD136. Additional laboratory tests revealed that the introduction of wax moth cadavers containing nematodes to the pool was the most ef- ficient method of nematode introduction. Field introductions of nematodes into sixteen plastic pools this spring gave reduced mosquito emergence. NICKLE, W. R. Nematodes of Bark Beetles. One or more types of nematode parasites, from 3-4 mm. in length, along with their progeny of up to 7500 nematode eggs and larvae, may be found in the body cavity of a bark beetle. These parasitylenchs and contortylenchs cause a reduction in the number of brood produced by the beetle if not total sterility. Another group of a few hundred nemas may be located in the hind gut of the beetle, feeding on the epithlial layer. One may find up to 200 larval parasita- phelenchs in the haemocoel of the beetle and hundreds more attached in a sticky mass to the underside of the elytra. Still another group, the cryptaphelenchs, are common upon dissection of the beetle. These nemas are attached to the malpighian tubules or are located in the gut of beetle grubs. Members of the phoretic diplogasterid group can be found attached to genital segments or elytra of bark beetles. PAIM, UNO and BECKEL, W. E. The Relation of the Gaseous Microenvironment to Habitat Selection and to Breathing in a Wood-Boring Beetle, A Summary. The problem was to discover as much as possible about the biology of Orthosoma brunneum which spends most of its life invisible in the dense medium of decaying wood. The gases found in various parts of logs, situated in moist and in wet locations, and at different times of the year are reported. In the laboratory the larvae of Orthosoma can survive in 0.8% of ambient 0: but they are killed within 10 days in 0.6% of 02. The larvae become narcotized in 43-47% 131 of CO. but they do not die even in ca. 80% of COs (in 10 days). The pupae of Orthosoma — can survive in almost pure CO». In logs in nature narcotizing concentrations of COs do not occur, but 02 below 0.6% is encountered in wet logs where Orthosoma is not found. The feeding larvae, in a gradient, aggregate in ca. 30-50% of ambient CO. In the autumn, when the larvae are not feeding, they no longer aggregate in any particular concentration of ambient CO». In the laboratory the adult females go to an outlet which emits CO. and they oviposit in the outlet. The males do not respond in relation to gradients of CO: concentration. In respirometers, while in air, the prepupae, the pupae and the resting adults release their respiratory CO. discontinuously, in bursts, at regular intervals. The larvae release CO: continuously. : The laboratory results are related tc the field environment. Maw, M. G. Some Effects of Unipolar Air Ions on the Flight of the Blowfly, Phaenicia Sp. Adult male and female blowflies, Phaenicia sp. were exposed for varying periods of time to artificially produced air ions of positive and negative polarity. Effects of the air ions were determined by the duration and speed of flight of individual flies on a flight mill. It was demonstrated that both positive and negative ions produced charac- teristic flight speed patterns and applications of alternating polarities indicated a pro longation of periods of high speed activity. : FRIEND, W. G. The effect of Various Nucleotides and Related Compounds on the Gorging Responses of Rhodnius Prolixus. A practical apparatus has been developed by which nymphs and adults of Rhcdnius prolixus c2n be fed artificial diets. The insects feed through a rubber membrane. In testing this apparatus it was observed that Rhodnius would quickly gorge on diets containing bovine red blood cells but that gorging on diets lacking these cells was sporadic and sometimes required hours. The gorging stimulus of the red blood cells could be mimiced by adenosine triphosphate (ATP) in concentrations as low as 10—~ molar. Further tests have shown that a series of nucleotides and related compounds, each containing a phosphate bond of high energy release, will induce Rhodnius to gorge on saline solutions. Fast, P. G. and ANGus, T. A. Effect of Crystalloid Parasporal Inclusions of B. Thuringiensis Var. Sotto on the Permeability of the Gut Wall of Bombyx Mori Larvae. As part of a continuing study of the insecticidal action of protein comprising the parasporal inclusion bodies (crystals) of B. thuringiensis var. sotto, permeability of the larval gut wall of Bombyx mori following ingestion of crystals has been investi- gated. By using various radioactive molecules it has been possible to establish quanti- tative differences between treated and untreated insects in transfer of such substances, lending support to the proposal that the lethal increase in pH, noted in dosed larvae, is caused by a migration of anionic components from the gut to the haemolymph. GRIFFITHS, K. J. Oviposition Preferences of Aptesis Basizona A(Grav.) when at- tacking Neodiprion Sertifer (Geoff.) Aptesis basizona (Grav.), a multivoltine European parasite of cocooned diprionid larvae, was introduced into Ontario about 20 years ago. It has recently become abundant as a parasite of Neodiprion sertifer (Geoff.) This ichneumonid attacks eonymphs, pronymphs and pupae of N. sertifer with equal fre- quency, but cocoons containing dead hosts are avoided. The larger female cocoon is attacked more frequently than the smaller male cocoon. This selection apparently can be made either without insertion of the ovipositor into the host cocoon, or after it has been inserted. MCcCLANAHAN, R. J. Food Preferences of the Six-Spotted Leafhopper, Macrosteles Fascifrons (Stahl). Selection of host plants by the six-spotted leafhopper was studied in a circular cage. Nine positions in a circle were systematically filled with three repli- cates of pots of three plant species. One hundred adult leafhoppers were used and counts were made hourly. After each count the insects were gently blown from their feeding sites. Plant species used in its tests included, cereals, vegetables and weeds. About thirty per cent of the leafhoppers were feeding at each count. Marked preferences were found, even between closely related plants. The findings are related to field observations. Boyce, H. R. Parasitism of Twig-Infesting Larvae of the Oriental Fruit Moth, Grapholitha Molesta (Busck), in Essex County, Ontario, 1956-1962. Parasitism of first and second generation twig-infesting larvae of G. molesta by the introduced braconid Macrocentrus ancylivorus Rohw. decreased suddenly to remarkably low levels in 1958. No appreciable recovery to higher levels occurred until 1961. Although parasitism of first generation larvae in 1962 was even higher than in 1961, that of the second generation larvae was 64 per cent lower than in 1961. Parasitism of second generation larvae of Glypta rufiscutellaris Cresson averaged 55 per cent higher for the period 1956-60 than in the preceding five years. In 1961, parasitism by G. rufiscutellaris increased to the highest level encountered since 1945, and increased further in 1962. 132 Examination of the effects on parasites of chemical treatments against the plum curculio, Conotrachelus nenuphar Herbst. and G. molesta, in 1961 and 1962, revealed no appreciable effect on parasitism by M. ancylivorus. The average parasitism by G. rufiscutellaris was reduced 49 per cent in 1961 and 27 per cent in 1962 by two cover sprays of 50 per cent DDT wettable powder applied against G. molesta. JAMES, H. G. Natural Control of the Rockpool Mosquito, Aedes Atropalpus (Coq.). Erosion of the bedrock of the Crowe River near Cordova Mines, Ontario has resulted in an abundance of rock pools which become populated with larvae of Aedes astropalpus (Coq.) and other culicids during the summer and autumn. Sampling and census counts in 1961 also indicated an extensive predator fauna, particularly in the larger pools. Of thirty-four invertebrates collected, there were many predacious forms among the nineteen species of aquatic insects. The release of mosquito larva tagged with radio- phosphorus (P32), and other methods indicated that 5 species of Dytiscidae, 2 Hemiptera, 1 coelenterate, 1 leech, 1 snail, and 2 minnows were predators. The most important was a small dytiscid, Laccophilus maculosus Germ. MONTEITH, L. G. Learning in Drino Bohemica Mesn. (Diptera: Tachninidae). Drino bohemica Mesn., a tachinid parasite of tenthredinoid sawflies learned to associate the movement of a small tray with the presence of host larvae. The parasites became habituated to an artist’s-type brush. The learning was retained for a period varying from a few hours to more than one day. There were differences in the ability of the parasites to learn and to retain their learning. The ability of the parasite to use a new clue in locating hosts would interact with other factors that influence host-finding and host selection. ARTHUR, A. P. The Influence of Associative Learning on Host Selection by the Females of Itoplectis Conquisitor (Say) (Hymenoptera: Ichneumonidae). Females of Itoplectis conquisitor (Say), a polyphagous pupal parasite of Lepidoptera, were ex- posed to host pupae in cigarette-sized paper tubes. The parasites learned to associate the paper tubes with the presence of hosts and retained this learning for as long as 14 days. They also learned to associate tubes of a particular colour with the presence of hosts. The ability of this parasite to learn suggests that it could concentrate on the most uudane host in the field, thus increasing its efficiency as an agent of biological control. SticH, H. F. An Experimental Analysis of the Courtship Pattern of Tipula Oleracea (Diptera). The courtship pattern of Tipula oleracea consists of a complex series of reciprocal stimulus-response reactions. The sequence of the reactions (grabbing, mounting, pinning, searching, kissing, and sliding reaction) is rigidly fixed,whereas the procedure of a reaction exhibits a certain degree of flexibility. Courtship may be broken off at any point between the males grabbing response and the actual copulation if a reaction cannot be completed, a sign stimulus is missing, or a sign stimulus is given at the wrong time. The grabbing and pinning reactions of the stimulus-response pattern have a specific “filter effect” leading to the copulation of active males with unfertilized, receptive females. These reactions also prevent a mating between two males or between a male and a fertilized or too young female. The grabbing reaction is also involved in the prevention of an inter-specific mating. ANNUAL BUSINESS MEETING The annual business meeting was held on November 16, 1962, in the Education Hall of the General Hospital, Belleville. Sixty-four members were present. The meeting commenced at 10:45 a.m. On motion of J. MacB. Cameron and W. G. Friend, the minutes of the 1961 (98th) annual meeting at Hamilton (Nov. 16-17, 1961), as published in Vol. 92 of the “Proceedings” were adopted. President’s Report President H. B. Wressell, in reviewing the events of the year, expressed the hope that, with the location of the Centennial Meeting now settled by the mail ballot held last summer, all members would pull together and make every effort to ensure the suc- cess of the joint meeting to be held at Ottawa next September. He went on to summarize the reports of various committees (see Appendix I) and outlined the main items to be discussed on the present agenda. Secretary-Treasurer’s Report The Secretary-Treasurer, C. C. Steward, then gave his report. He presented an interim financial statement to October (Appendix 2). Membership stands at 235, including three honorary members. Letters of good wishes have been written to a number of old members, now retired. A fidelity bond of 133 $2000.00 has been purchased in the name of the Secretary-Treasurer, according to a resolution of the directors last year, to comply with Section 7(1) and 7(2) of the Constitution. The result of the mail ballot shows the following elected as Directors for the 1962-1963 term: T. A. Angus W. F. Baldwin A. W. A. Brown De Ae «Chant W. G. Friend W. E. Heming A. Wilkes In addition, H. B. Wressell, as Past President, is also a director for 1962-1963. On motion of C. C. Steward and W. G. Friend, the Secretary-Treasurer’s report was adopted. Grant to Zoological Society The directors recommended that the Society contribute $100.00 to the Zoological Society of London to aid in the publication cf the ‘Zoological Record’’. The Secretary- Treasurer reported in this connection that the current “Insecta” volume of the Zoological Record, as requested last year, had been received. On motion of D. G. Peterson and H. R. Boyce, the grant of $100.00 was approved. Resolutions D. G. Peterson and W. E. Heming (Resolutions Committee) moved four resolu- tions (see Appendix 3) conveying the thanks of the Society to those concerned with the organization of the present meeting. Carried. A resolution was moved by W. E. Heming, seconded by G. G. Dustan, that the Secretary-Treasurer send letters of good wishes to well-known retired members, includ- ing Dr. J. D. Detwiler, Dr. E. M. Walker and others. Carried. Election of Fellows The President read Section 14 of the Society’s Constitution authorizing the election of fellows. Two, so far, have been proposed. These, together with any others that may be proposed, will be voted en by the membership at the same time as the election of directors next June. Insignia The directors last year requested the Secretary-Treasurer to submit a design for a suitable Insignia that could be used by the Society on letterheads, stationery, etc. The design has been completed, and was printed on the Program of the meeting, and on the banquet menu. After some discussion, it was moved by D. G. Peterson, seconded By A. AG A. Brown that this design be adopted by the Society as its official Insignia. arried. Location of 1963 Annual Meeting The President reminded members of the result of the mail ballot held last May and pointed out that this decision must be confirmed at the present meeting. It was moved by D. A. Chant, seconded by W. G. Friend, that the result of the mail ballot be confirmed, and that the 1963 annual meeting of the Society be held at Ottawa, simultaneously with that of the Entomological Society of Canada, as a Joint Centennial Meeting. Carried unanimously. . Centenmal Committee Report Mr. G. P. Holland, General Chairman of the Centennial Executive Committee, gave the meeting a comprehensive outline of the plans of the Ottawa Centennial Com- mittee, bringing the meeting up to date on all arrangements made so far. The financial plans and arrangements for sources of revenue were discussed by Dr. B. M. McGugan, Chairman of the Centennial Finance Committee. The President expressed his appreciation to Mr. Holland and Dr. McGugan, and, on motion of D. G. Peterson and C. C. Steward, their reports were accepted. Grant for Centennial Meeting Expenses The President stated that the directors recommended that a grant of $500.00 be made to the Joint Centennial Committee to help defray the expenses of the 1963 meeting at Ottawa. Moved by J. MacB. Cameron, seconded by W. C. Allan, that this grant of $500.00 to the Joint Centennial Committee be approved. Carried. 134 Auditors On motion of C. C. Steward and D. G. Peterson, C. J. Payton and K. W. Meek were appointed auditors for 1963. There being no further business, on motion of D. G. Peterson and J. A. Begg, the meeting was adjourned at 12:05 p.m. APPENDIX # 1—Committee Reports Publications Committee The Committee was concerned solely with the preparation of the Society’s ninety- second annual report to the Minister of Agriculture for Ontario. The report was pub lished, by authority of the Minister, as Volume 92 of the Proceedings of the Entomologi- eal Society of Ontario. The Minister kindly provided the Society with 1500 copies of the Proceedings. Two hundred copies were delivered to the Librarian. The balance were sent to members of the Society, other members of the Entomological Society of Canada, subscribers to the Canadian Entomologist and those organizations and institutions which exchange their publications for the Proceedings and/or the Canadian Entomologist. Volume 92 con- tains five papers presented at the 98th Annual Meeting in a symposium on unconven- tional approaches to insect control, three reviews on insects of special entomological interest in Ontario and 13 submitted papers. The section of the Proceedings that reports on the activities of the Society was expanded by the inclusion of the titles of the papers that were presented at the 98th Annual Meeting and abstracts of those that were not published in the Proceedings. There are a large number of typographical errors in Volume 92 of the Proceed- ings. An errata sheet, listing 65 of these errors, was enclosed with each copy. The Editor acknowledges his responsibility for this regrettable situation and has investigated its causes. An unusually large number of errors were made in the original typesetting and existed in the galleys sent to the authors for proof-reading and correction. The Editor concentrated his attention on the correction of the errors noted by the authors. An inadequate reading of the page proofs by the Editor resulted in his failure to note 53 errors that existed in the galleys but were not detected and corrected by the authors. The Society must suggest to the Minister or printer that an improved printing service is required. Authors must proof-read galleys with greater care and attention. Finally, the Editor must establish an improved proof-reading system at the page proof stage. D. M. Davies W. G. Friend D. G. Peterson, Chairman Library Committee Accommodation The library is now set up as a separate unit in the Biology Building of the Ontario Agricultural College, Guelph, and is equipped as a reference and study room. All books and periodicals have been sorted and catalogued so that it is a simple matter to locate any known reference in stock. Binding and Purchases: The issues of the “Canadian Entomologist” and “Proceedings of the Entomological Society of Ontario” have been bound to date, and a quantity of library envelope binders were purchased. The binders are made of stout cardboard and are splendid for filing periodicals and paper bound publications. Many such issues have already been boxed and catalogued and it is planned that the remainder will be completed soon. Inbrary Loans: During the past year 62 library loans were made. These covered a wide field of biological literature, and requests were received from such places as: Ontario Research Foundation; Universities of Saskatchewan, New Brunswick, McMaster, Western, British Columbia, McGill, Acadia and Queens; Libraries of Canada Department of Agriculture, Department of Forestry, Fisheries, National Museum, Imperial Oil, Re- search Foundation, Entomology Research and many others. In addition, the library was used by many staff members, graduate students and biology majors of both the Agricultural and Veterinary Colleges. Many workers in other fields and from other laboratories have made use of the facilities which are now available through our library service. 135 Hachanges: No new exchanges were added to the library during the past year. At the present time there are approximately 90 exchange agreements in effect with the “Canadian Entomologist” and approximately 15 with the “Proceedings of the Entomological Society of Ontario’. As all exchange publications are being received at reasonably regular intervals, no outstanding blanks or misses have occurred. W. C. Allan, Chairman B. V. Peterson G. F. Townsend Common Names Committee: At the Annual Meeting of the Entomological Society of Ontario, held at McMaster University, Nov. 16 and 17, 1961, I was represented on the Common Names Committee by Miss Isobel Creelman. Unfortunately, only one other member of the committee, Mr. L. A. Miller, was present and no formal meeting was held. In informal discussion, however, Mr. Miller indicated that since he was no longer with the Department and more or less out of touch with insect nomenclature, he felt that he could contribute little to the committee’s work. Also it was noted that Mr. W. G. Watson is no longer with the Department. Under the circumstances, it would seem that some action on committee membership is in order. The following common name proposals were submitted by members of this Society during the year: Contarinia virginianae Felt — Chokecherry midge Dasyneura gloditschiae (Osten Sacken) — Honey locust pod-gall midge Euxoa detersa (Walker) — Sand cutworm Gryllus pennsylvanicus (Burmeister )— Northern fall cricket Gryllus velatis (Alexander and Bigelow) — Northern spring cricket Oryzaephilus mercator (Fauval) — Merchant grain beetle Tribolium destructor (Uttyenboogaart) — Large flour beetle Trirhabda pilosa Blake — Hoary sagebrush beetle C. Graham MacNay, Chairman Common Names Committee Program Committee: The report of this committee is really the program itself, which has already been mailed out to the members well in advance of the meeting. We believe this year’s Symposium, more exactly a Seminar ‘How useful is the basic research programme to economic entomology?” will prove to be stimulating and interesting, and we hope that many delegates will take part as there should be plenty of time for discussion. _The number of submitted papers, 24 including 5 student papers competing for the President’s Prize, appears to be about the right number for meetings of our Society if there are no concurrent sessions. We are privileged to have the opportunity to hear, as our guest speaker, Professor C. E. Atwood of the University of Toronto, who will give an account of the international conference on social insects held at Pavia, Italy, last year. An item of particular interest is the exhibition of anti-malerial postage stamps by Dr. A. P. Arthur. These stamps were issued during 1962 by a large number of countries at the suggestion of the World Health Organization. We wish to thank Dr. Arthur for all the time and effort put into this display. Exhibitions and displays, whether of direct concern with entomology or on the cultural “fringe” help, we believe, to add to the interest and pleasure of our meetings. _ Despite the fact that members of the committee were widely separated at Kingston, Belleville and London, we were able to hold two full meetings at the Belleville Entomology Research Institute. We express our thanks to Director B. P. Beirne for enabling these meeting to be held there. H. A. U. Monro, Chairman Joan F. Bronskill J. S. Kelleher A. S. West 136 APPENDIX #2—Financial Reports Interim Financial Report, October 31, 1962 Receipts Bank balance, Dec. 31, 1961 ....... $ 961.57 Membership dues received ....... 1,550.00 Sale of reprints from : PEMNCECCOINGS hee ae aN 1,146.60 Sale of back issues of PERROCCC OMNES iui ela iad e 8.00 Banmarlmberest lo. 38.64 Grant from Ontario Minister of AXOTNCICY O13 eee ae ne aR ieee 300.00 FPR MANGn ae ale bu Fe 2.81 $4,007.62 WiaeuOry DONS 6 becca: 400.00 Guelph, October 31, 1962 Financial Statement, 1962 Receipts Membership dues received ........ $1,613.00 Sale of ‘Proceedings’ .................... 9.00 Salevor reprints fade 1,146.60 Grant from Ontario Minister Ome Nore WTI 300.00 Exchange on cheques ................. 2.43 Beame IMberest oy ei ee 38.64 Bank Balance, Jan. 1, 1962 ........ 961.57 $4,071.24 WaevOLy Bonds 2. ee 8 400.00 Auditors: C. J. Payton K. W. Meek APPENDIX #3—Resolutions Resolution #1 Expenditures Dues transmitted to Ent. Soc. ESCO al OL Ha te\(o ke yet ian eas 2 $1,164.00 Printing of Reprints from *PYOCCEOIN GS. einen Baie, 643.92 Postage and HWxpress .................... 193.00 Stationery ...... Riteestee aa cee eee 69.13 Library—book-binding and flim SyDORESers ee ee eee Grant to “Zoological Record’... 100.00 Purchase of Gestetner machine 303.83 AUIGICORS?, LEG vs) a) oes hermes 5.00 Miseellaneouss us nee ee ee 10.55 Bank balance, 31 Oct., 1962 ....... 1,348.31 $4,007.62 Victoryebonds.s. 0 oe ee 400.00 C. C. Steward, Secretary-Treasurer Expenditures Dues sent to Ent. Soc. of: Canada irae cakes. ee $1,200.00 Library— binding and cataloguing ......... 187.88 Postage and Express ................. 263.70 Pacincine:: i RVe RIN t Seki ae eee ee 643.92 Printing: Letterheads ................ 39.44 Stationery sis: cc Ga ee ee 36.05 Grant to Zoological Society OPmeondonwue. ts hee eee 100.00 1962 Annual Meeting—printing Of) PROS AIT fe for suis eee lee 89.47 Presidents-Prize, 1962. 2 50.00 Purchase of Gestetner duplicatine machine: 22)... =. 303.83 AMGICORS HHCO™ ees 25/5 ere hee meee. 5.00 Secretary-Treasurer— honorarium £96260 2) une 20.00 Secretary-Treasurer, Fidelity bond? premium. 4 tee ee ae 8.00 Miscellaneous ioe" 2 ken nee 155 Bank Balance, Dec. 31, 1962 .... 1,112.40 $4,071.24 Victory:: Bonds: 42. 22 eee 400.00 C. C. Steward, Secretary-Treasurer January lst, 1963. WHEREAS the Society was invited to hold its 99th Annual Meeting at the Ento- mology Research Institute for Biological Control by its director Dr. B. P. Beirne; and WHEREAS the Institute has provided excellent services and organization which have produced an outstanding meeting BE IT RESOLVED THAT the Society, through its Secretary-Treasurer, express its sincere appreciation to Dr. Beirne and his staff for the excellent arrangements made by them. Resolution #2 WHEREAS the Belleville General Hospital has provided excellent accommodation for the Society’s meeting in the Education Hall of the Nurses’ Residence, BE IT RESOLVED THAT the Society, through its Secretary-Treasurer, express its sincere appreciation to Mr. Daeschsel, Administrative Officer of the Hospital, for these facilities. Resolution #3 WHEREAS the Program Committee, under the chairmanship of Dr. H. A. U. Monro, has planned a most successful program for this annual meeting, BE IT RESOLVED THAT the Society, through its Secretary-Treasurer, express its sincere appreciation to the members of the Committee for the outstanding program presented at the meeting. Resolution #4 WHEREAS the Local Arrangements Committee has, through its concentrated efforts, contributed in an outstanding manner to the success of the meeting, BE IT RESOLVED THAT the Society, through its Secretary-Treasurer, express its sincere thanks to the members of the Committee for its excellent work. PRESIDENT’S PRIZE Four papers were presented by students at the 99th Annual Meeting of the Society in the second competition for the President’s Prize. The judges were C. E. Atwood, Toronto; F. W. Fletcher, Midland, Michigan; and D. G. Peterson, Guelph. The President’s Prize for 1962 was awarded to Waldemar Klassen, a graduate student in the Department of Zoology, University of Western Ontario. Mr. Klassen presented a paper entitled “Insecticide resistance and the genetics of Aedes aegyptv’. This work is being done under the U.S. National Institutes of Health grant to Professor A. W. A. Brown for “Studies of insecticide resistance in mosquitoes”. Mr. Klassen was born in Vauxhall, Alberta. He received his early schooling there and completed high school in 1953. He then entered the University of Alberta and received a bachelors degree in 1957 and a masters degree in 1959. He served for one year with the U.S. Operations Mission in Bolivia and in 1960 ae as a Ph.D. candidate in the Denartment of Zoology, University of Western ntario. Qu Memoriam .olec@lalecacelalela.elecelale.e.elelelalecarelaelaceleleteraleraleararalaratelstae! ALVIN VALENTINE MITCHENER, 1888-1962 A. V. Michener died suddenly at Ottawa on June 19. Born at Clear Creek, Ontario, he attended public school there and high school at Fort Rowan, Ontario. He taught school for two years, obtained a B.A. degree from McMaster University in 1914, anda B.S.A. degree from the Ontario Agricultural College in 1918. He then taught entomology at Manitoba Agricultural College until 1927, when he received an M.Sc. degree from the University of Manitoba. For the rest of his professional career he taught entomology at this institution, being Dean of the Faculty of Agriculture from 1938 to 1946, then chairman of the Department of Entomology until 1954 when he was appointed Professor Emeritus of Entomology. He is survived by one son, Ralph, a Bureau of Statistics employee at Ottawa. Mrs. Mitchener (nee Myrta Gowdy of Guelph) predeceased him in 1951. Professor A. V. Mitchener was a stalwart entomologist. He received his own training in our profession under Professor Caesar at O.A.C. and he dedicated the rest of his active life to training his students in the simple but honest habits and virtues that served him so well. For nearly two decades he worked alone in the Department of Entomology, serving the public of Manitoba in the control of noxious insects and improvement of apicultural practice. His administrative abilities were recognized by the University of Manitoba when he was appointed to the Office of Dean of Agriculture in which he served for eight years. As a teacher, Professor Mitchener was meticulous about formal details, perhaps to a fault, though many of his students both entomology majors and others have testi- fied that his example in stylistic matters proved useful to them in the work-a-day world. As an undergraduate student assistant, I can recall the latitude he allowed in the first awkward endeavours in research, in sharp contrast with the rigid discipline he imposed on younger students in the classroom. As a researcher, Professor Mitchener exemplified a virtue of cardina! importance — enthusiasm. Though not himself a taxonomist, he nursed the Department’s Reference Collection to a stage of permanent usefulness. Though not in any strict academic sense a specialist in any of the fundamen- tal sciences he was not without an appreciation of the relevance of physiology and genetics and other disciplines basic to entomelogy. As a man, Professor Mitchener was forthright in manner, immaculate in appearance and unbending in integrity—so much so that not everyone could empathize with him on brief acquaintance. Nevertheless, his sterner miens were emphatically not the only aspect of his natural self which was generally cheerful, optimistic and even humorous. In addition to his professional duties Professor Mitchener played an active role in his community as a member of his church and the school board. He was a keen participant in various forms of extension activity. He invested himself in public ser- vice within his capabilities and with an evident exuberance in all his activities. His choice of deeds and his manner of doing them implied an amalgam of duty and pleasure. A. J. Thorsteinson 139 JAMES HALLIDAY McDUNNOUGH, 1877-1962 Dr. J. H. McDunnough died in Halifax, Nova Scotia, on February 23, 1962, and entomology lost one, and almost the last, of the North American entomological pioneers. The last 53 of his 84 years were devoted to sytematic entomology, and during that period he published almost 300 papers, and without doubt was one of the best authorities on North American lepidoptera. His last paper was published just one week: before his death. A list of most of his publications appeared in The Canadian Entomologist, 1962, Vol. 94, p. 1096. To Dr. McDunnough, hunting for anything but insects was a sheer waste of time. Those of us who indulged in the rod and gun were in his opinion doing nothing more than demonstrating atavistic tendencies. His interests other than entomology, revolved around classical music, the theatre, and the better dining rooms. He strongly disliked “the hash-houses and the horrible aroma of greasy potatoes”. Although interested in the affairs of politicians, he was quite convinced that “politicians were obviously crooked, and obscured this characteristic in clouds of patriotism”. On the other hand he retained his ancestral Irish humor, and when in a jovial mood, would greet me with “the top of the morning, Tom. The goose hangs high”. He always walked to and from work, three times a day. He delighted in walking, and much of his field work was accomplished by long walks. When an automobile was required, he was dependent on someone else, and to my knowledge, drove a car only on one occasion. About 1925 he purchased a Model T Ford, and on his first trial run, collided with another vehicle on Hurdman’s Bridge, near Ottawa. In disgust, he walked away, never to try again. At the office, he insisted on almost absolute quietness, and we whispered or spoke in subdued tones to one another. Anyone unnecessarily disturbing the tranquility that prevailed was “rude and raucous”. This atmosphere was conducive to well regulated and organized work habits, and to him procrastination had no existence. He always replied at once to any request concerning the work. His prompt identifications were not merely a list of names, but in many instances outlined how the form could be recognized, if it Was common or rare, and other short notes on its distribution, food plant etc. He was also unsurpassed as an entomological technician. His dissections and mounts of insect genitalia were flawless, and no specimen was placed in the collection unless it was perfect, or almost so. His philosophy that correct taxonomic interpretation could not be made from poor specimens was well founded, and as a result his work is standing the test of time. His intense interest in his chosen field left little time for outside interests. Holidays, and entomological or other meetings were to him designed for idle people. Thus his boundless energy and interest, and his aesthetic sense of values formed the nucleus, and set the standards for the development of what is now one of the best insect systematic organizations to be found anywhere. To those entomologists who did not know Dr. McDunnough personally, he will be remembered through his writings for many years to come. To those of us who knew him well, he will also be remembered for the gentleman he was, and for what he strove to do. So to you Sir, may we say posthumously, “The top of the morning. The goose still hangs high.” T. N. Freeman. EDGAR HAROLD STRICKLAND, 1889-1962 __. Professor Strickland, Colonel Strickland, Dr. Strickland, or just plain “Strick”, it is sometimes difficult to remember that these four titles refer to the same familiar figure. Professor Strickland founded the department of entomology at the University of Alberta in 1922; he established the reputation of this department single-handed before the Second World War, when as Colonel Strickland he resumed a military career suspended for 25 years. In command of the Canadian Army Basic Training Unit at Wetaskiwin he synthesized his experiences as teacher and soldier to the lasting benefit of all who went there. Through his early experience in the Canada Department of Agriculture and his later training of many of the entomological staff for this department, he was well known to most entomologists in Canada. His nresence at a meeting was an assurance of its success; he always seemed able to provide that fresh and unexpected viewnoint which defeats stagnation, and at the same time the sound practical wisdom which keeps attention focussed on the subject. 140 If there is one thing a department of entomology must have above all else, it is insects. Professor Strickland provided them abundantly at Edmonton. This was his vacation activity; whenever he was not working with them, he was collecting them. His collections are the most important part of his material legacy to the department. Much of his scientific output consists of taxonomic studies with these collections, in which he enlisted the aid of specialsts from all over the world. But he was no narrow specalist himself; all the major problems in applied entomology in Alberta bear witness to his practical originality. While taxonomy and applied entomology took most of his research time, the former led him into significant morphological work such as that on the ptilinal armature of flies, with its physiological outcome, and the latter was based on a flair for ecological observation in the field As retirement and the move to Victoria approached Professor Strickland became aware of the fact that he would inevitably be addressed there as Doctor Strickland. Rather than accept this without earning it he worked for one of the first D.Sc. degrees to be awarded by the University of Alberta; the degree was granted in 1954. And so he came by his third title; but the one he had most use for was none at all, he liked best to be known as ‘Strick’. When he died last year many Canadian entomologists felt that they had lost their entomological father. But his work lives on; a memorial fund has been established which will be used to this end. Further details may be obtained from the department of entomology at the University of Alberta in Edmonton. A full biography has been published in the March, 1963 issue of the Canadian Entomologist. Brian Hocking JOHN BRAITHWAITE WALLIS 1877-1962 Canadian Entomology lost one of the last and one of the most active amateur entomologists in the death of Mr. J. B. Wallis in March 1962. He had been in failing health for several years due to acute diabetes, but in spite of his physical handicaps his mind was active and he was bright end cheerful. It is fortunate that he lived to enjoy three great events in his life. The birth of a grandson (John Wallis), his election as honorary member of the Entomological Society of Canada on the publication of his book The Cicindelidae of Canada. “J.B.” as he was affectionately known by his friends was born in England and emmigrated to Canada in 1893. He entered the teaching profession which he followed all his life. He taught first in country schools but was soon (1903) invited to Winnipeg to pleenie nature study in Winnipeg schools. He later served as principal and superin- tendent. It is fortunate that one of his first schools was near Treesbank, Man., where he met Norman Criddle and Dr. James Fletcher. His close friendship with Norman and the Criddle family was a mutual stimulation. He became a naturalist and collected extensively in all groups. He specialized in Odonata and Lepidoptera but later limited his activities to the Coleoptera. He published on the taxonomy of several groups and is best known for his monographs on the genera Haliplus and Odontaeus and his treatment of the tiger beetles of Canada. “J.B.” was of a retiring nature but he took a great interest in young people and encouraged them to collect and study nature. His kindly and understanding character won him many friends. He was active in sport, soccer, cricket, tennis and curling as a young man but dropped them in favor of entomology when he moved to Winnipeg. He, however, retained his interest in hunting and he enjoyed nothing better than to go to the duck marsh or after upland game with his son or the Criddles. Mr. Wallis is the end of an era, the passing of which is much to be regretted. With the pleasure of modern living and community committments few have the time to follow entomology as an avocation. a) Bird 141 Vv. INDEX A Anunteles ‘glomeratus 2.0. (ie. A Venue atl ha, ee at aces We 65 AMVISEC DIVUALLES COLDER, -c. oi6 Bin ah os aes ns ecw ee et Ee RS 36 ACOYTOLLCTIO VCLULINOIG \ pices. sie Shes eee cede pee oP eae 23, 13 A seogaster: Guadrudentata | J. 2 a... 55 ceo ag re Bho ec Mite ce 35 B BOP CCULUS .....06...8 4a. es 16 Resistance: to, IMmsectieidesii..ce. ic tee ee ae a ee Vd: 36 - ARV AINT A SRS § Se Te nte deao SAU lee oe a et hoe a ace A7 +) DOVE oh ee eRe es Soa SERN io ny ote ghee Gee et eee 47, 49 SUNULUM OGNALINUM, NEW. SPeCIES 42 ison ben ce ee 96 Six-spotted leaf hopper; food preference of j22.0.2..45 0 6s eee 90 table-‘of host plants... 2 hie Necks ee 92 SOLENOPSIS MHOLOSEE PS hes joe TE EE 8 OP SO ae 385 SLerier MAES, Se Ol se ee oe isis pee LN 50 T PENA eD Yeh aay en erin Te ee yee ere eA, Be Gi ce ee Se 79 LELY adaptable: Vitus eee ee ee a ee ens 14 sheligd eines (fe weve ee em cee oe. F a ferewe esomt bes CONGR ete, ee inet ee ee 87 eiMeravUre. (CtTewEs ON ese kon gel tone 2h say Lat sete ieee ates eae wit Ss = 40 ECHCUROIGES CONLMUMST — eee oe | AGA SUS eo ogee ie Ce San le >, eee 35 PRECIO OTOL). Pee RG as FR Ee ah Sgr RE Re ERE NEI GEOL te, De Re See 37 PUTT INTHE Ck oe: 0 es: cee ek UMS eee 4 Le ee 35 PE CCR OPTUS UR Ub oO kIT aie bomen oA Oe MR OS) Pe > re 61, 85 Vv Memusegiseases: of insects: 200.4058 oa ee a Ue ee ee 3; 33 WwW Weather conditions, affecting leaf hoppers ..... sbbak, ERROR CALL NAGAR ate 93 Z PEROSCINMLMLELCeLa, pepper MAaevot 6. Asie ee ee ee haa Sige eee meee 75 144 AUTHOR’S GUIDE 1. Two copies of a manuscript are required by the Editor. 2. Manuscripts should be prepared in the manner described in the “Style Manual for Biological Journals”, published by the American Institute of Biological Sciences, 2000 P Street, N.W., Washington 6, D.C., U.S.A. ($3.00). (a) Citations in the text to bibliographic references should be made by use of the ‘name-and-year’ system. (b) Refer to Volume 93 of the Proceedings for examples of type and style of titles, headings, ete. 3. Correspondence concerning, and orders for reprints should be addressed to the Editor. ah a a 2 ~~. Sy = = P, i ju Ges My Nr ty le By NN easy ! 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