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L", liin- He.- I -nnii, >! 2n)Win2-lM...l .,n„ ,.„.!, ,,r lai.-h Th..|„,,vwi ,, .mi .■, hi- „ Ki«. . -KunX;^:,'i:;';;'!.l'\-:'!';,:: r:::,/'' ;';;;,^;:;:.;l".rn:tJ" ■''•" -"""' '' '^'=- !■.<;. II, .1,1:1,1 ii.il » DOMINION or CANADA L' '^VRTMENT OF AGRICULTURE EXPERIMENTAL PARMS. DIVIS ON OF ENTOMOLOGY THE LARGE LARCH SAWFLY [Xematus erichsonii] WITH AN ACCOUNT OF ITS PARASITES, OTHEK NATURAL ENEMIES AND MEANS OF CONTROL C. GORDON HEWITT. D.Sc. Domtaie* EatemQiotUt BULLETIN No. !•.— Second Series Entomological Bulletin No. 9 Bulletins of the Second Series of the Bulletins of the Experimental Farms treat of such subjedx as are of interest to a limited class of readers and are mailed only to those to whom the information is likely to be useful Publl*h«d by dinction of the Hon. MARTIN BURREIX, MlnUtir of Agricultur*. Ottawa. 23544—1 OTTAWA OOriRiniENT PBIMTINO BUBEAI7 1912 DIVISION OF ENTOMOLOGY. Dominion Entomologixt — ('. Cordon Hewitt, D.Sp. Chief Assidant EntomolMjist — Arthvr (iiHHON. Assistant Entomologist for Forest Insects—.]. M. Swaine, M.Sr., B.S.A. Assistant Entomologist for Apiculture— F. W. L. Sladex. Field Officers— U. ('. Theherne, B.S.A. (!. K. Sanders, B.S.A. J. D. TOTHILL, B.S.A. W. A. KoH«, B.S.A. (J. Beavliei', B.A., I.L.B. ('. E. Fetch, B.S.A. Inspector of Indian Orchnrds—T. \Vil.son. Secretaries— J. A. Letoi:rneau, Superintendents of Fumigation Stations— \. K. Leith, Winnipi'R, Man. H. E. (iooLD, St. John, N.B. , St. Johnx, Que. ('. Wrhjht, Windsor, Ont. O. N. (lAHNER, Niagara Falls, Ont. Laboratory and Apiary Assistant— J. I. Beailne. Centbal Experimental Fabm Ottawa, Ont. Mat, 15, 1912. To the Honourable The Minister of Agriculture, Ottawa, Ont. Sir,— I have the honour to submit for your approval Bulletin No. 10 of the Second Series (and No. 5 of the Division of Entomology) entitled "The Large Larch Sawfly," prepared by Dr. C. (lordon Hewitt, Dominion Entomologist. The Large Larch Sawfly has, in the past thirty or forty years worked inestimable injury to our tamarack or larch forests in Canada. The immense areas involved, the rapidity of the spread of the insect and the usual inaccessi- bility of larch forests in summer, all combine to render the control of this'insect pest, by artificial methods, quite impracticable. For these nta-sons, investigations, of which this bulletin is a brief report, have been carried on in the control of the insect by natural means, such as mammals, birds and parasitic insects. This work has been in progress for several years, in a broad field, covering practically all the larch growing areas of Europe and America. The conclusions should therefore be of exceptional value to those interested either from a scientific standpoint or in a practical way in the control of the spread of this insect and in preserving the larch, constituting as it does no inconsiderabi* part of our forest wealth, from injury. I have the honour to l>e, sir, Your ul>edient 8»Tvant, J. H. GRI8DALE, Director, Dominion Experimental Farmt, 23644— 1 J CONTENTS. PAGE. Introduction 7 History and Distribution 9 Description 12 Parthenogenesis 13 Life-historj' 14 The Depredations of the Insect, their appearance and effects 18 Food plants 20 Natural Enemies 21 Mammals 21 Birds and Bird Encouragement 22 Parasitic Insects 25 Predaceous Insect 35 Parasitic Fungus .36 Preventive Measures 3g Remedial Measures 39 Economic value of the Larch 41 ■ ! ' - 1 ■ ■ ; I: ■ 1 INTRODUCTION. The Large Larch Sawfly' {S'ematua erichsonii Htrtig) is the most serious in.sect which attacks the iarch {Larix spp.) which in North America is also called the tamarack or haekmatak,' these Ixing the native Indian names for the genus Larix. Its original home would appear to be Europe where its attacks were first recorded, and I lielieve it was introduced into North America. My chief reasons in support of this belief are as follows : wherever it is found, it displays a most decided preference for the European larch ( Larix europaea). It was not discovered in North America until about 1881, when it was found first in the Harvard Arboretum, into whic'. a large numl)er of trees of various kinds are annually imported from all parts of the world. Its wide dist..bution, however, would indicate an earlier introduction. Introduced in this manner, without its native parasites, one would expect its history subsequent to introdrction and establishment to lie what it actually proved to lie, rapid and devastating as will be seen in the following account. It has spread through the eastern portion of Canada and the United States and has destroyed from fifty to one hundred per cent, of the nativ«' larch or tamarack (Larix americana). Had it Iw-m a native insect it is ^ robablo that its history would have been different and its depredations less destructive. In England, its depredations, though smaller in .itent, are economically more serious at the present time than in North America, where the larch, except when cultivated as an ornamental tree, does net yet constitute an important factor as a timber product. Its value as a timl)er tr -e in Canada will undoubt-dly increa.se with the exhaustion of the supply of other species of trees, apart from the fact that for certain purposes it is unsur- passable, as will l»e mentioned later. Furthei , the American larch, L. americana, will grow in swamps and muskeg regions, large areas of which occur in Canada, and which are un-suitable without drainage for any other type of conifer-produc- ing saleable timber. Before the beginning of thij study in lOOt), the insect had not received much attention in Europe, brief data only having been given bySaxesen, Tisch- bein (1840) an< Ratzeburg. The only available account of value was that of Packard^ resultin. from his study of the insect in the eastern states of the Union in the years 1882 1884. This account, however, was not verj" complete and it was vf -.y desirable that a more complete .study should be made of its life-history habits and mean^^ of control both natural an(l artificial, especially in view of its relation to the English plantations of larch whose preservation is of (5reat importance. The results of my preliminary investigations and recom- meridations resulting therefrom were incorporated in three reports made to the Witerworks Committee of the Corporation of the city of Manchester in August, 1907, November, 1907, and March, 19()S, respectively. These results, together with further studies of the life-history and natural means of control, were nui)li: >'' at the re(jue.st of the Board of Agriculture in 1908,* a previous account i<{ Pi J's work and the English outbreak having been writti-n by Mac- Doug This work was continued in the Department of Economic Zoology of the Alanchester University (Eng.) and in the F>nglish L; ke District and a 'Thi» "pcit'i? U callvd popularly thf lairat' Larcli ^*Bw(ly to diatinauiali it (rimi tlip aiiiiilliT black spprii>!i J.yiia f A'rmufiu) lariat Hrtg. whicli attacks tlii' larch in Kurope and which 1 huvr ruari'd in Knf;land. 'In Nova Scotia the larch is frcqui-ntly calUni the ' Junip<-r.' 'Packard, A. S. "I'ifth Report of the United Staton Knt.>iiii>!>>Eical "oiiiiia.Hsion — ln*.Tti injurious to forest and shade trees," 188«-IH1»0. i .V. rrirluimit, pp. S79-890, pis. 1) and 26.) ^hvM'itl, ('. (i. "The Large Larch Sawfly, \rmntuit I'richmmii." .h^nrn. Btmrd Atiricutlur^. Vol. li, pp. UiU-imO, I pi. IDOS. 'SlaeDnugatl, K. S. "The \Aitni: Ijircii SawHv, i.Vimo/i/» rrirhmnih." Jnv i , 3iiaril of Agriml ure. Vol. 13. pp. 3SS-S9i, I pi. 19119. ' 8 ™^ rLI^'^i? on the progress of the work was given to the Association of Econo m.c Biologists at Oxford ,n July 1909.« Two months later, I left England for Canada to t^ake up the duties of Dominion Entomologist. Opportunity wm now afforded to study the insect under North American conXbns 17so^ workers st.Il doubted the identity of the species. During the pS Th^eTyear therefore, the msect has been studied in Canada and in th^ UniteTsK' l^T'V^\''''^'"^'' ^^'- ^- ^'- B- E^^^'ds, the Forester of tKanehest^; whir ^""uh ''^'/'"^ ""^ ""PP"*'" °^ '^^ ^"'^"^n^ f™™ Cumberland (England) wh eh enablH me to contmue my studies of the English parasites of the sawflv an. also to study the European form side by side'^with the Amer can form' Jn^nS""^'"*^ •'' an a, , ount of the work I have -arried on since 1906. It is not complete-no mvest. gallon can oe so considereu-but it appeared advisable at this stage to wnte as complete an account as pns.ible in order to a.S further work, and the further studv of the means r.f ccntrol. I wish to acknowKe my indebtedness to Mr. Jo.seph Mangan of the Manchester Unh er^ftyTEn?? Sttin' ^''^'""^^jhe work in England, under the direction of Prof. S J Hickson s.n -my departure in 1909, and who has kindlv comminicated to me his results, which coincide with my own, and which have b -en publish^^ smcethe greater part of this was written. a e u en puoiisnect 'ftweedii«8 of the Association of Economic Biologists, „„. 6-7. Vol i of Journ Fr,nu.«,u B. /™ 1 I- \ n > ! * i i fcME.^-. •.-.■•. .Itt-I^ HISTORY AND DISTRIBUTION. In Europe. Previous to 1840, this insect appears to have J)een recorded twice in Europe as being injurious tn Larix europaea. In the Hartz mountains it was recorded by Saxcsen and on the plains of Holstein it was found by Tischbein who observed the adults on the wing in the middle of May. Ratzeburg^ describes it chiefly from Tischbein's account and gives a brief account of its habit.*^, together with an excellent figure. It has been recorded at different times in Swedei', Holland and Denmark and, in 1907, it wr^. reported to me from Switzerland. Prof. Paul Noel, of Rouen, and Prof. Henri, of Nancy, inform me that A'', erichsonii is not known in France. It has been recorded from Finli-, Harvard University, would appear to indicate that it had been observed several years previous to 1881 : — "The larvs appear of late years on European larch in different parts of Eastern Massachusetts, and threaten to become a serious drawback to the cultivation of this valuable tree. July B, 18g: Mr. ('. S. Sargent. The determination is mine. — H.A.H." Packard (t.c.) gives an account of its distribution in the United States up to the time of writing (1890). In 1881 it had been reported in Maine, and it wa.s observed at Brun.swick in Maine in 1882. in these years, very great tlestruction of larch was caused by the insect. It was found in New Hampshire in 1882. Lintner' first observed it in the State of New York in 1883, the in- festation covering many square miles of swamps. It has l)een found in Penn- sylvania, where, in 1892 ("Insect Life," lol. IV, p. 219), it was recorded as injuring hemlock. E^xtending westward, it has invaded Minnesota, and Ruggles' (1910) states that it has become a very serious pest on the tamarack in northern Minnesota. Its western limit in the United States would appear to correspond fairly closely with that in Canada. Hopkins' recently stated that "during several extensive outbreaks since 1880 (it) has killed from fifty to one hundred per cent, of the mature larch over vast areas in the north-eastern Unitetl States and south-eastern Canada. It is evident that the amount of merchantable- sized timber that has died as a result of defoliation by this insect will aggregate many billions of feet." In 1883. Fylcs reported its appearance in ea.-tern Canada on Larix americana {Can. Entom. vol. l-'i, page 20.i, ISS^i) and two years later Fletcher* gave an account of its occurrence with some observations on the habits of the larvae. It was found throughout the province of Ontario, Quebec, New Brunswick, and Nova Scotia. J. J. .Jack'' in reporting the depredations of the sawfly in Quebec in 1885, states: "I had notice(l these larvae on the larch trees in former years, but they were not so generally abundant and I had not the opportunity to study them. My father has told me that about thirty years ago the tamarack woods were entirely defoliated and looked as though .scorched by fire, and he thinks that the sawfly larva? were probably the cause. It was more noticeable at that time as there were large tracts of land covered with tamarack forest that have now entirely disappeared." In 1906, when the ext<'nt of the infestation in Canada and the results of the insect's depredations again assumed a serious magnitude, Fletcher" gave an his- torical account of its occurrence in Canada subsequent to the year 1882, which appeared to have been the year of its arrival in Canada from the United States. During the next three years it effected enormous injuries to the American larch or tamarack. He states: "After three or f^ur years of being stripp«'d, the larches over millions of acres and practically over the whole of eastern Canada, were almost wiped out. With this large destruction of its food plants, the insect practically disappeared and little has been heard of it until last year (1905) when it again became noticeable upon ornamental European larches and, in a few places, was observed on the young growth of larches in swamps." 'Lintner, J. .\. "Kiftli Rcpiirt on il Injurious iinJ otlirr Inwcts of the State of N'ew York." ISS'J. pp. 104-17.'i. ^RuQyteit, A. (i. "Tlie fjurcU .SuMlty {LitU'ritnemntut nirhiim'ti HiirtiKi in Minnt'.s.>la." CaHiititan Kntomoloai»l. Vol. il. pp. 9S-94, 1910. 'Hopkim, A. D. ".Some Insift.-i injurious loForr^ts.— Inaeet depn-dationa in North .Vniericau Forests and practical methods of prevention and contri)!. ' Bull. \o. SS. Par' V, pp. ST-IHI. Bur. Enlom. f'..S, Depl. Agr. 1909. 'Fletcher, J. "The Lurch .SawHv, .V. ericksonii." fifteenth .innwtl Report of the Ent. .Sue. of Ontario, pp. 7t-77, 1885. ^Fletcher, J UUOO). "Report of the Entomoloni^t and Botanist" in the Report of the Eip. Farmt o Canada for 19011, pp. 190-191. 'Seventeenth Ann. Rep. EntomoluQiral Hoe. nfUntnrio, ISST, p. IT. 1 1 12 Further, he states: "A feature of the last outbreak of 1882-1885 was the rapidity with which the attack spread and the suddeimes's' with which it dis- appeared. Occasional specimens of the sawflv or of the ( lonies of the larvte have been seen from time to time since 1885, but there has, been no noticeable destruction until nhe present year. The territorj- over which this insect is known to have spread in the old outbreak is all through Ontario, Quebec and the Maritime provinces right up to Labrador." That is, the infested area appeared to coincide with the distribution of the Larix. It was not thought that the last outbreak had reached west of Lake Superior but, in 1909 and 1910 I found that most of the larches along the Canadian Pacific Railway almost as far as Winnipeg had l)een stripped by the larva, although I did not observe It in the prairie provinces nor in British Columbia. It has also been reported to me by surveyors and engineers from James Bav across to Labrador. In July, 1911, Mr. N. Criddle reported the defoliation of tamaracks about 120 miles west of Winnipeg, and in 1910 it was reported by the Forestry Branch from Battleford, Saskatchewan. The occurrence and depredations of this insect in the Riding Mountain Forest Reserve in Manitoba, were reported to me m 1911 by .'^fr. T. R. Dickson of the Forestry Branch of the Department of the Interior. These observations indicate that it is' gradually spreading westward; in eastern Canada it is perhaps safe to say that its distrioution corresponds with that of Larix americana. DESCRIPTION OF XEMATUS ERICHSOXII, HARTIG. IV:}, (Plate I. Fig. 1.) This species was originally described by Hartig' in 1837 under the name of Nematus erichsomi. Marlatt, however, in his account' of the Nematinse of North America has included it in the genus Lygaonematus of Konow^, although the characters differentiating this genus from Pachynematus do not appear to be very great. It has also been included in the genus Holocneme. Marlatt has also included Cresson's Nematus notabilis, descrilied from Massachusetts in 1890, in this species. His description of the male was made from a single Canadian specimen. As I am able to confirm his description from an examination of about twentv males which I have reared in England and Canada in 1908, 1909 and 1910, I shall give his description of the species, with a few modifications, more especiallv in the description of the male. (Speci- mens in coll. Div. Entom., Ottawa). Female. The females vary i little in si. ^ but the average length is 11 mm. and the expanse of the wings is 20-22 mm; they are moderately robust in size. The head and thorax are finely punctured, entire body shining; clypeus scarcely emarginate, almost truncate; frontal and lateral ridges of ocellar basin rounded, indistinct; vertex nearly smooth; antennal fovea long, shallow, deepest at apex; antennae about as long as head and thorax, rather robust, tapering, joints 3 and 4 subequal; sheath broad, rounded, truncate tip; cerci flattened and tapering; intercostal vein hyaline, indistinct, but anterior to basal and nearly at right ^"gl^'^ ^o costa; first transverse eubita! indistinct or wanting, stigma uioder- 'This sudden disappearance does not appear to have im-n due, as is soiiif times the caw, to the effect of natural means of control but to the exhaustion of the food supply owing to the death of the trees re- sulting from repeated defoliacion. ,,. 'Original description in "Die Familien der Blattwcspen und Holiwespen nebst eioer allgemeincn l:.iileitung lur Naturgeschichte der Hymenopteren " Berlin, 1860, pp. 187-188 Bull ^3 Tech's^' ^I'm"'" °' ^^^ ^'■'""•'"»« "' ■^'""h America." C.S. Dtpt. Agr. Dit. Entomology, 'Deutsche Entom. Zeit. vol. 35, p. 247, 1890. 13 ately broad, not ^cununate; claw with minute inner tooth near apex. < liour black, tip of clypeus, basal two-thirds of tibiae, apices of trochanters and ex reme angles of pronotum yellowii^h-white; femora, tips of anterior tibise and their tarsi, dorsal and ventral siiu's four basal abdominal segments, except i the proximal portion of the first segment, orange-rufous; extreme tips of n 'die femora above, hind femora more broadly, distal half of hind tibje and th( ind tarsi blj>-ck; wing veins black except the costa which is fulvous and the anal em which is whitish; wings slightly infuscated; dusky spot in the second cu ital cell is large and prominent. The posterior end of the abdomen as seen from the sides is shown in Fig. 7, B. The saw-like ovipositor is seen projecting sligiitly and one of the saws is shown in Fig. 8. Afale. The male is .smaller antl slightly more slender than the female, 't.s average length being 9 mm. with a wing expan.se of 15 mm. The abdomen i» not wider than the thorax and is of a uniform width; procidentia keeled, somewhat con- stricted basally, short and not projecting beyond the seventh '"r I segment; terminal ventral segment very slightly emarginate at the trun oex. Th»- terminal ventral segment of the male is shown in Fig. 7, .\ tir, black antennae, four basal segments of the abdomen dorsally, tfxcep non «>( the median region of the first segment, the lateral regions of tl and sixth segments, the whole of the ventral side of the abdomen and tt xcep» the bases of the coxae, reddish-yellow; the tips of the tibise an*' ; the \ trd pair of legs dark brown; portion of the face below the ani iwrtion of lower orbits, pronotum and tegulte, creamy white; wings as in A. Fio. 7— A. Ventral view of poaterior end of abijoiiirn of male, .V. encli .11. B. Lateral view of posterior end of abdomen of female .V. enrh.. ,nii, showin« positor slightly protuding. PARTHENOGENESIS. Nematus erichsonii is almost a wholly parthenogenetic species, hat , fhe females lay eggs almost entirely without fertilisation by the male. "Thu pro- portion of males to females is generally less than four per cent., and w he three years 1908-1910 when the numerical proportions of males and females emerging were observed, it was found that a total of 6,181 cocoons yielded 6,158 females and 23 males. Mangan {t.c. 1910) states "the parthenogenetic origin of the vast majority of the sawfly larvae was again evident as hardly more than two per cent, of the samples which emerged were males." In no case during mv investi- gations was a female seen in coitu with a male and all the larvae which have been reared have hatched from eggs deposited by unfertilised females; fertilisation was easily prevented by so great a scarcity of males, in fact it would be difficult to obtain fertilised eggs. This fact, the occurrence of a normal parthenogenetic habit, has no little influence on the abundance of the insect as the female begins 14 ttl'SSIJrolS'S."'^'-?'" •"°^°« •»<"'»"»">• .lep™d.«e upon 1^ I "" *-«; eS ^ i!i;«ie'^;;;i.ss,iy m.;;;;;^'"' ••' '-"" ''■ ""*-"••• !!;] LIFE-HISTORY. previous Lord^or^pk«?H Zl^'T^^.u ^TP"»^" «">'' confirmation of the pri vious records of I'ackard, which were the only recordM existing of a mmnUf» u r-u. J"*"rf'" '^t^^^l' Packard's ol^ervations were inTrrect i is^^'^H^e no doubt to the fact that he did not work with much material nor doe^ he apwar £ M7r'Ml^ai"„7rh"Tf"*'\ ^-v «r? «»-.-rvation. have'Sf^^fiK ^onor A '^*"K»"' o' ^^e Manchester Univers ty (Eng.) who assisted me in 1909 and subsequently continued the work in England. tTm"?tar'tr""";*'T«^^^"""« »""^^^^^^^^ te Sdle of mIv ^p"T'7rl'*^'". '^T'**' *»•« ^^""'^^ as occ"rri„rab5ut .j«wfl.es are seen on the wi.,g in England until the S^f Ju^>^ ihe emer^it te-.P^"^ ''T " ^''""^ ""^ **" "'"^t^^- ^ this account/ one Sn"lv S ii'"*^"^" '"^f °" *'^ "P"" **>'ch recently-hatched larv« are S seen ever e^Lr •'*'7K''',*r*' mistakenly inferred a se^nd broodf^n no c^e hoT- ro:^J^ttl^^:tJt^!rTLl! °"*''*^^'.'^'^.«« "^dult emerged from a c;o5^n lormeq m the same year and the spt-cics ,s without doubt single-brooded ar..! i«nTT"'^* ™™ ^^^ •■*'?^"''' »•'« ^^'"''•«* «»«^flie^ soon take Tthe wine • Xntmrr'. Vol. g». pp. StSS. (Mar. H, I8lt.) i Mil 15 Ovip moN. The female invariably i-booi4e)« the young terminal ».MJoti« upon which to clepoHit her eggn; in no rase have eggtt been I'ound upon the lateral vertinlH of leavem. The insect usually stands with the head directed towards the twig and grasping the young leaves she bends the terminal portion of the abdomen downwards until it is almost at right angles to the shoot. The saws are now extended and an incision made into the tender stem of the green shoot. Mr. Mangan, who, in 1909, made careful observations at the time of ovipositior , found that it usually took from three to six minutes to make the incision a- ^ deposit the egg in the slit thus made. Three and a half hours would he spent in ovipositing on a sin^e shoot. Each female deposits from forty to fifty eggs ; this has been confirmed by dissecting out the mature eggs from the ovaries. This number may be de- posited on a single shoot; in some shoots as many as seventy eggs have been found, but the usual numljer of eggs deposited on a single shoot appears to be about thirty. In the majority of cases, the slits are made only along one side of the young shoot and the eggs are placed alternately. In some cases, the eggs may l)e three or four abreast and owing to the subsequent growth of the shoot their positions may \tf changed and »he shoot curls over as will l)e de&cribe seen within the eggs and in all i-ases Kio. 9 — Portion ot terminal iihuot of lno'li in which tfft o( -V. rrichsonii havr Ijorn inscrtrd by tht- (iiiial.-. their heads appear to Ije 'c also black. There are seven pairs of abdomina'. .ppendages. The dorsal surface is glaucous or greyish-green in colour except immediately behind the head, which, like tne ventral surface, h pale or sea-green. The demarcation between the two Fio. 10— Head of mature larva of N. ericktonii. colours is very distinct laterally. The dorsal surface is also covered with very minute and separated tubercles. Scattered over the body are a number of short brownish spines. The skin of the larva is thrown into slight folds, on naany of which a row of wart-like tubercles can be distinguished. The man- dibles are four-toothed and the maxillsp four-jointed. In the New England States, the larvae usually become full-grown about the end of July or beginning of August. Packard states that a few still occur on trees in Massachusetts ablate as the last week in August or early in September. The first cocoons not under experimental conditions were found in England at the end of July. I found larvae, in England, at the end of August, and in 23544—2 18 I Canada durinR the latter part of August. As the breeding experiments have siiown, in England they may beeome full grown as early as the first week in July and in Canada by the middle of June. This «lisi)arity between the first and last dates for the larva? corresponds to the length of time over whieh the time of emt rgence for the adults is spread. When they are full grown, they descend from the branches of the tree to the ground where they .spin brown, fibrous cocoons beneath the turf or moss round the base of the trunk or under stones. The habits of the larva? ar«' of interest. Mention has already been made of the habit which they have of turning up the hind portion of the Inxly over the back, making the larva somewhat S-shaped. This action no doubt corres- ponds to the "terrifying attitude" adopted by larva- of the other orders, par- ticularly the lepidopterous family Sotodontidae. When the larvse are in the third and fourth larval stages, they congregate in mas.ses, as many as sixty larva> having been counted in a single mass. These are usually the larvje which have emerged from the eggs deposited in the same terminal shoot. This habit is of importance in the eradication of the larva> as will be shown later. In discu.ssing the remedial measures Packard states: "Jarring the trees will prove a good remedy, the worms once shaken off the tree cannot ascend the trunk as they do not, like cankerworms, climb trees." This is incorrect. When the larviE are dislodgj'd from the branches either by tli(> wind or rain, they re-ascend the trunk and ultimately regain the branches and twigs. The prevention of this is dis- cussed later. Cocoon. The cocoon measures 10 mm. in length and .i mm. broad. It is dark brown in colour and fibrous in character, having a fairly firm texture. In the cocoon the larva contracts and passes the winter in the larval state, unchangi>d n colour, changing to the pupa in the following April or May, usually two or three weeks before tlfe emergence of the adult. THE 1)EPRED.\TI0XS OF THE INSECT, AND EFFECTS. THEIR APPEARANCE The sawtiy larva belongs to that large class of leaf-destroying insects which are ecoiioniically important by reason of their defoliating forest trees in an extensive manner. While, however, the main damage is inflicted by the larva*, this sj)e(ies is unique, as this study has shown, owing to the fact that the adult insects themselves inflict injuries of a serious nature. The effects of the attacks, therefore, must be coiisitlered sej>arately ;is caused by the adults and larvse re>])ectively. TiiK Inji KKirs Ekfk(T of tiik .\urLT S.\wflv. In depositing the eggs, the sawHy invariably chooses the young, green, terminal twig in which to insert the eggs, as I have already indicated in describ- ing the oviposition. The result of the injuries inflicted during this process is that the terminal twig either dies or is permanently injured and distorted. (See Plate 1, Fig. 2.) Where a large number of eggs have been deposited all round the length of the yoinig terminal shoot, it usually turns brown and dies anti the presence of tliese curled-up, brown, dead terminal shoots o'ten serves to indicate the presence of the l.'irvje on the* tree. When the terminal shoot is killed in this m.'inner the growth is arrested and the form of the tree may be affected. In many cases the eggs are deposited along one side only '-W 19 of the young termina' shoot, with the ressult that the growth on that side is seriously interfered with anf the injureil side. The extent of the curvature varies, but n.t infrequently it will curve through tt complete circle ami continue growing in the original direction. dis- lui. U- Winter aspirt <>! l!iritir« cl|.(i)riiic emerge from the eggs they begin to feed. At first they feed along the sides of the needle-lik<' leaves giving them a .serrate character iind causing them to curl and wither. ,\s they grow thev '.cgin to eat the whole of the leaf, beginning at the ai)ex and gnawing it letely to the base. In this manner they destroy all the leaves on a singi mil and all the verticils of leavi's on a branch, with the result that the tree, c ntirely stripped of its green Ic'tves, has the norm:!! winter appearance in the middle of summer. The defolia- tion of the tree usually begins on the lower branches. This is no (h)ubt due to the fact that the females, on emerging, deposit their eggs chiefly on th.' terminal shoots of the l(>wer branches of the trees and when the larvae emerge they de- foliate the.e branches, subsetjuently working their wav upwards and stripping ihe whole of thp tree 23544— 2J t ao When the trees have been completely defoliated for three successive years or more, they usually die. The death of the tree is sometimes caused by its efforts to overcome the effects of defoliation. Trees which are defoliated in the summer will sometimes produce a second crop of leaves late in the year from what would have been the next year's buds. Not only is this a severe tax on the resources of the tree but these leaves are usually killed by frost. Forest trees and those closely planted are moreSiable to succumb to the effects of repeated defoliation than more sparsely planted or isolated trees. This is due to the fact that the former are usually provided with a crown of green leaves only, and this is the sole means of obtaining organic food. The lo.ss of this source of supply is ^ore .serious to the tree than the loss of the foliage is to an isolated tree wbosi, branches during the summer are green to the base and able to store naore reserve food during the short time the leaves are present. • Ij'f depredations of the larvae are usually first noticeable in July, the strip- pmg of the leaves producing a brown appearance. In the case of a serious attack the trees will be completely stripped by August, and the bare twigs and branches give the forest the appearance which it has when the trees are devoid of their leaves in the depth of winter, the larch being a deciduous tree. As the larch produces its leaves eariy in the season it naturally might be concluded that, by I!^^,!i"*'i • ^V""^ "^^'f •■^"o^'ed by the sawfly larvje, the trees would have 3'^^ ,«"™^'«''*. reserve food material to minimize the prejudicial effects of un- Tif ♦ ?u- <^.^f°''^t'?n ''efore the proper time. Experience teaches us, however, that this IS not the case and that closely growing larches succumh to the effects of repeated defoliation after two or three vears. i i I :■' I SSUBSEQUENT INSECT ATTACKS. When the tree has its vitality reduced by repeated defoliation bv the sawflv larvse, even though it may not succumb to the depredations of the sawflv it IS more liable to be attacked by a number of species of bark beetles belonging to the group of Scolytidae or Ipidae, the most destructive and deadly of all forest insects. Certam of the more common bark beetles attacking the lareh in eastern Canada have been described by Mr. J. M. Swaine' of this Division ?„Lr 'Jl "•'*' ^^^^^' ^^n^joct.uus simplex Lee, is common in eastern panada and occurs in the north-eastern states of the Union. It will attack iving trees when they have been weakened or injured, destroying even the largest timber. Ips balsameus Lee. may also attack larch. Other species Zf ^f .*„fr l^- ^J'^'^u^'^ ^"^ DryocwUs autographm Ratz, Dryoccetesn. sp. fhf/ff r f "'"'r^.'u''- ^L' **'^'^ *'P*'"^" '"'•^y ^"ack lareh trees weakened by the defoliation of the sawfly and complete the destruction should it not have been already accomplished. FOOD PLANTS OF A'. ERICHSOXII. So far as I have been able to observe, both under natural conditions and bj experiment, Nematm erichsonii feeds only upon species of Lareh (Larix) in torests and plantations where other conifers occurred with larch, althoujth tl iff,*?'' ""-f"'- ^^ ^"'"P'etely defoliated the larv« did not appea^o touS the other conifers such as species of Picea, Abies or Pinus and 1 was not able to induce them to feed on these species in the experiments. Reference has hi I892! ^ however, to its occurrence on hemlock in Pennsylvania, '"Some Inaects of the Urch." For(j-/!r./ Ann. Report Ent. Soe. Ontano. pp. StSS. mi. 1 21 Among the species of Lanx, as I have already stated, the larva, showed a most decided preference for the European larch, L. europaea, (L. deeidua Mill ) under natural conditions. Nevertheless, as the history of the insect in North America shows, they defoliate and kill the American larch, L. amerieana Michx. (L. lanana (du Roi) Koch . I have also found them feeding upon and de- foliatmg the Japanese larch L. leptolepis End!., which some foresters have believed to be immune, and also upon the Siberian larch L. gibirica Ledeb. Ihe la.«t species has been found attacked by the sawfiy in Finland. NATURAL ENEMIES. When an insect, such as the larch sawfly occurs over a large area the natural enemies are the only factors which are able to control it. This beiM the case the study of these natural enemies and of the means by which they may be eflFectively increased and assisted in their work constitutes the most important section of the investigation. The natural factors in the control of L. enchtonii have been studied since the beginning of this work and although this section cannot be considered to be complete, it describes so far as it has been possible to discover, the chief natural enemies. These consist of mammals, birdroara- sitic and predaceous insects and fungal parasites and they will be considered in uw oT?hem°*^ '"^*"' ^^"^ ™*^ ^ "^ '•^''^ ^'^ ''**°P**'* t" "al^e Mammals. »♦ Z^!u^^'^ ■"S""- "»»mmalian enemies of the sawfly are of interest as thev K„lrivnLl,rr 7r "* '*^*^' "'""^'^'' ^^^ '=°^°°° «*'«'^' '° '^hich the insect is safe irom most of its enemies. The Field Vole or Meadow Mouse, Microtus (Arvicola) agreslis. In November 1907, it wa.s found that large numbers of the larvae were beine extracted from the cocoons of the sawfly in the Thirlmere region of the English Lake Fio. 12-FieM vole or meadow mouse, Microlm ttgrtitii, eitractin« larvae of X. eriehtonii from cocoons District. At the base of a single tree hundreds of empt v cocoons could be found at the entrance of and along the burrows of the rodents. The marks of the teeth at the edges of the open ends of the cocoons first drew my attention to the fact .J |i !> ^^> 22 ■Plate 2 rjg.23). Later, this species was taught in traps baited with hil)ernatinK mr'-e which had been extracted from the cocoons and on microscopic examin- r ^" J the stomach contents of the rodents it was found that the larvK cons- --uted practically the entire diet of the voles or meadow mice at that time oi the year. In all the larch woods which were visited, large numbers of the empty cocoons were found and the voles wore most active in burrowing under- neath the turf around th' ses of the trees in search of the cocoons. It was Mtimated that the larv .^d been extracted from alwut 25 per cent of the •ocoons collected in different localities in 1&07-8. In the following year their .vTi-Tifrl*'' '^ '* '.' Tr ••ff^'-tual Hnd al>out 50 iM-r cent, of the cocoons .'xamined had been attacked by voles. The insect-eating habit of the vole is not a little remarkable as they are normally phytophagous and constitute one of the forester's chief pests This change of habit which the presence of an abundance of food induced,' which also happened in the case of the birds, altered for the time the economic standing of the vole and, .s they were obviously acting as important agents in the control of the sawfly, their destruction was not advised unless they should increase to dangerous proportions. ^ The White-foote. The Rooks (Crows) not only took the larva off the trees but were found to feed especially upon the full grown larva; when they \vere on the ground and crawling under the turf to pupate. In many instances the turf round the bases of the trees was riddled with holes made by the beaks of the birds searching for the larva;. Annand' observed rooks, .starlinp^. tits and jackdaws fee.ling upon the larv.-r, He records the fact tli.it the j.,y was most u>eful in searchiiiK for the cocoons and extracting the larva*. It was not a little surprising that these bin'.: consumed the laivje in large quantiti. as the larva of N. erichmnii appear to h.-ive a resinous flavour which ordinarily might be considered distasteful to a l)ir(l. B Fio. 13— Structural dotails of nestinx 1m« for bird cncouraijcincnt. A. NV! outside of which bearing the bark was rountl and the inside square. The fourth .-ide was iiuule up of a flat piece of wood forming the back of the box; this piece was longer and projected above and below the l)ox thus providing means of attaching the box ►o the tree. The top and bottom of the box were made of slab wood. The bo. torn was nailed on and several holes were l)ored through it to keep the nest dry. The top was hinged to the flat board :6.5 1910. 57.5 1911. 65.9 ni„ I J*"; K"""^"?' .'""«■»•■"*. from year to year of the p..rcentagc of the lM>xes occu- Tn^i^ in' .h"*' " 'k'-' ^'Kl»fi^-»"t' especially as there was a concomitant yearly mcrea.«e ,n the number of Ihjxcs provided. The number of boxes which were provided was small, but the results of the experiments were sufficient to ndi^ate among other things, that in localities where nesting .sites are few lirds Sh readily use nesting lH,xe« if these are provided, although this fact h7rdlv required confirmat.on in view of the experience in certain of the German foest^^ and else- where. It al.so indicated that in proportion as more facilities were provided for nesting, more birds availed themselves of the opportunities. OnTevera "r"' aTi thl?1 'Y f"" ^''"^^^ ^"'^ '•^•'" ••''•^'^** «!"""« ♦»>«' season In a sS box All these facts demonstrate most clearly the value of the provision of nesting boxes as a means of increasing bird liYe and the proportion ousefu nsect.vorous birds ma given region. The Inixes distributed ill the plantSns o hardwoods were utili.sed nu.rc generally than those .lisiribut. in Santa ions tti' tv'i"?K ^' T^ ^"'■*'^"" ''^'^'''''^ '^^^ *he birds, including the ts favoured he type of box whose construction has l,een described above in preference to he Berlepsch type of which a number were distributed. The Jre erence o" the former made the p rcentage of nests oc -upied probablv less thank wouh have been if all the nes, ,oxes had been of the ype the birds-appearecHo prlfer! P.\RA.S1TE8 AND PheDACEOUS InSECTS. Although birds and mammals are important factors in preventing the ^2TZ' '"'^"IJT'"^ f "?^"'"' ^■°"^^°' ^^'»>^" «nit6'raroiAor»/, /. /.. C. "Irlineuiiionoliigm Kuroprje." Vol. II, pp. 173-175, |g29. '11 III '[■ 26 in ii foot-note to tJie description of M. nuliciM in Mr. Moriev's r.-eont account of the British Ichneumons (Vol. IV, p. 157. 1911) in which referonco to Mr Alangan s use of this specific name is made: 'Both Dr. V. (Jordon Hewitt, and Mr. Halhert of the Dublin Museum tiave given me examples of the Menoleius I)red from the ("umberland Holocnem/ and they are certainly distinct from, though closely allied to, M. aulicus Orav' 1 Uo not recognize the species and have not met with it elsewh.Te: it mav Ix- new and I hope to refer to it at some future time." As lapse of time and further study appe^. ■ .; to have changed Mr. Moriev's vi|Mvsm regard to this Ichneumon since • iu.-l ^v black, of subcvlin- (Irical and apical mcisures of second and third segments obsoletelv r«'fuscent • tlie three basal n- segments gradually explanate; the first strongly earinate basally, slightly long.-r than liimi coxa- with its .lis.-al sulcus narrow and distinct t.) centre and in s stronger, spiracles before its centre Lasal scrob,-s large and subcircular. and postpetiole .rf j finely margined' yentral i)lica of o' stramin.-ous ami valvula- of 9 not compressed; terebra ohhquely defle.xed, apically truncate and not exten.ling Ix-ycmd anus I.eirs fulvous an.l not slen.ler; hin.l ones with their tibiae di'stinctly spinulose and bhu'k with a broad testaceous band before the ba.se and the bhick .•alcana longer than half metatarsi: their tarsi bla.'k and .listinctlv subin- cra.ssate with onychij large and ..iiyches stout; .' with tro.'hant.-rs an.l anterior ro.'.a; straminous whit... ih.- hin.l vnxiw .astam'.ms or bla.'k .and their .'al.'aria with basal two-thir.ls of tibiir white. Wings hyaline ■in.l s.imewhat bn.a.l; ra.lix an.ll.'giilie stramineous; stigma br.)ad an.l infuscate piceous: .•ir.M)l,-t wanting .)r v.-ry rarely sub.-ntire. transy,.rs,. an.l p.-tiolate _einitting th.' bit.Miestrate recurr.'iil n.-rvur.- furth.-r fr.)ni the int.'rciibitjii 27 than tlie latter is long; lower basal postfumil and but little oblique; anal emitted from centre of braehial cell ; first recurrent of hind wing a little longer than basal radial abscissa; nervellus opposite and geniculate hardly below its centre. I.ength, » 10 mm. In structure it is very closely allied to Mcsohitix (Scopesus) pallidifrorix Holmgr.. a> set forth by I'hom-ion (Opusc. Ent. 2032) and by its author, both in his Monogmphia of lSo5 and Dispimtio of 1876, which is said to differ fnJm the females of Mesoleius imitrilor and M. geniadatus Holmgr., in the apically more broadly (h'pressed clyr-inis, etc., but materially differing in its nigrescent stigma, pale coxae, trochanters and 9 tegulae, posteriorly broader head and very determinate metaiiotal carinae. Among our British species it must be inserted after Menoleim bicolor Grav." The average length of .1/. teiithredinin is 9..5 mm (alM)ut three-eighths of an ijich) and the breadth across the (>xpanded wings is 17 mm. In 1908, from 331 coco(ms of S.erichsonii, 1!) specimens of this parasite emerged, indicating that 5.8 per cent, of the larva" had been parasitised. In he winter following, .a large number of cocoons were collected and in the summer of lOOlt. out of 5,821 cocoons, there emerged (i24 specimens of Mesoleim tenthre- diniif, indicating that the number of larva; parasitised had increased to 10.9 per cent. On account of my leaving England in September, l!H)n, arrangements were made to continue the study l)y having cocoons collected in the spring and shipped to Canada. This was done and in the summer of lOlO, 1,200 speci- mens of M. tenthredinin were obtained from 1,!)4() cocoons, a i)ercentage of 04.7. Practically the same degree of parasitism, namely 02 i)er cent, was observed by Mr. M.ingan in England. The result of this "high degree of parasitism on the part of M. tenfhredinin, associated to some extent, no doubt, with other controlling natural factors such as voles, birds and the fungus f^ariaforuio.sa, was that the sawfly was jjractically eradicated. The larches in the infested region which had been completely defoliated in the previous two years were perfectly green. Mr. Mangan informed me that the sawfly larv:e were very scarce. The history of the pest was of great interest as indicating the oi)erati"(ms of natural means of control. On account of tlu- economic importance of Memleiux ienthrrdiniH as a natural factor in the control of the sawfly, arrangements were made to import the parasitised cocoons into Canada with a view to establishing the parasite in different regions within the infested area. Owing to the comparative scarcity of the pest it was unu.sally difficult to collect the living cocoons in large coon« infested with J/, tenthirdinix in 1910, the.se emerging, of course, in 1911. Of the cocoons received from Thirlmere, England, in 1911, statistical studies were made of two small collections only, the rest of the cocoons l)eing distributed in the hope of establishing M. tt'iithmliiiix in Canada in the manner I have just mentioned. In the collections of cocoons which were retained at Ottawa, out of 202 cocoons, 25 specimens of .U. tvnthmlinix emerged, indicating a p.arasitism by M. tenlhrfdiiiix of 12.5 p«'r cent. In the collection of cocoons which wjw .sent to If 3f II 't ! i \M 28 VnU^: ^ ^^V'*' State Entomologist of Michigan at thr Michigan Agricultural oS^^cSleettn'nS'^co'o'i '' ^°""' ''■ '^"'^^^'-'^ '--'^-"^ ^'O' ^'eS' Via. U-Full-«rown larva of .\te,ot,ius tenthrfdinU Morlpy. tenthlMtTftu^r!'\^^^'' *^: P^-'-^'-nt'^Ke of the iarv» parasitised by .V. ,Z int r *>*V J ^"' ■ ^'^ P'-'-'-entagc parasitised by such species as Microcrm^ tu^Jahrahs and Apte^s nigrocincta had increased slightly: this irdSid it is evident that M. tenthredinis is a most important factor in the control The mriiful date upon which .«. lenOiridMa »a.» found to cmetiti. rmm f h. , ",4s,'"i>iS,''VE;;iJ:rT "",?■ *■" ™"™vourin,«to bu., .",3,; that tho ovarii ofVeutaltT S;,™...d,„itlS*'Kv "Xytllv Valopinthiu itemah'cida Packard. '• A num>)er of cocoons sent to us by Mr. Atkins were found in everv c««p to he tenanted by a minute rhalcid parasite, belonging ^tli genus tfro dS Ma> 7883*^ Th?T '""/'^ ^^'"" ^ll" 'r"""" '» »»>« l^e.dinJlS "" ii'?«n!^rrVpp!''3f ?«!"■''•"""'•'' •'""• «'"• "' "'- f •""-'i«b„..r of Agrifulturu. 1»«3. ««,,.. M. 29 Beyond the figure of t!ie parasite, which is given and again reproduced with the above account in the Fifth Report of the United States Entomological Commis- sion (1890), no further description is given. The correspondence in this account would indicate that Mr. Charles F. Atkins collected the cocoons in Maine. Until this insect was rediscovered in Canada and described by rae (1911)' with observations on its life-history, made with the assistance of Mr. G. E. Sanders of this Division, I am not aware of any description of it having been given subsequently to Packard's brief reference to it. It was first reared from cocoons of the sawfly collected in the larch section of the forest belt on the Central Experimental Farm, Ottawa, in May, 1910. Mr. C. T. Brues, of the Bussey Institution of the Harvard University, con- firmed my identification of the species as Packard's P. nematicida and placed it in Forster's genus Ccelopisthia. The occurrence of the parasite was discussed with Mr. W. F. Fiskc in charge of the Gipsy Moth Parasite Lalwratory (of the U.S. Bureau of Entomology) at Melrose Highlands, Ma.ss., who also examined cocoons of A^. erichsonii collected at Wellcsley, Ma.ss., and found the pupseof this parasite in these cocoons on July 28, IDIO. Mr. Fiske most kindly arranged for cocoons to be collected for me from the same localitv and these were received on Sentem- ber 13th. " * The following account of the life-history of this parasite is taken from my paper already mentioned and subsequent observations have been ad'led. It is to be regretted that it has not been possible so far to follow the development of the several broods of :t single line of parasites through the complete vear. Kio. 1.5 -f aloputhia nemaiinU i'aik. IVnialo cnlawii 1.' tiiii.M, .'■^^■KS^\^ Flo. 16 — I''i'n\alp C, nematicida uviponitinK in coomm »( .V. erirhumn. (I'nlurKcd). The development of the last and overwintering brood was studied. Females were ob.served ovipositing on September 13th. The time occupied in the process varied. A single female which was isolated for olwervation, remained in the same position for Ifa hours (see Fig. 16) with her ovipositor inserted in the cocoon. She then removed her ovipositor and walked away, moving alwut for twenty minutes, after which she returned and inserted her ovipositor in almost the same spot as before and remained in this position ovijK)siting for fifty-five minutes. 'Hnntl, CO. "On falopiitkia ntmalicida Paik. A Chalciil PuraMite of the I,»rgo Larch ijawfly /.WOHiiirfflafuf erichtonii Hartig." Can. Entom. V'li. i3, ji/j. tDTSOS. t !■ ' '■'■■■■ .1 If! : it 30 s were .seen ovipositing in flic same cotoon. < u ^ that may bo deposited in a single cocoon In several instances, two fi Tlie numerical ahundauce of tl. SXS^t'"''"rh"'''''V^' ' — -'^«hty-o.^Vgg;;;;;;;;^e;rra snge lar%a, m ^iother case fo.. even pupie and adults were contained in a Mngle cocoon. Five cocoons exami„ed on May 1. 1912, contaimnlTO S fiO 73 and 50 lary* respectively. Tl.e sawfly larvai in cocoons in whC-h the chaJcS ml • K; lS::r'""' '"" V^" **■"" *''"^" '" »ninf,.cte!l 'ocooS "v'ip- siting • '*'""' P'"""'>'^'"K '"•♦'"" «" ♦'"• PHrt of the female when ,.v..iiP^ *^Y7 •^■"""- '" '"'■1'^^'' ""*' "-ansparently white. In shape thev ire mally e ongate havn.g one end broader han the other, an.l are sliglUv curv.^ In '^ • ^- 1 .^'''' '"■-' *'''Py'"»«' ''Eternally upon the snwflv larva chieflv i Ih anterior and thoracic region an.l appear to b,- lai.l in masses with noXn nt , placing them, were this possible. In three ,lavs all the lar i^ ha "/c L' from egg.s deposite.l by females on Sept.-mber 13th ' "' the cocoons of the host. Mature larva- of the overwintering l.rll were n,;,;," A IS '■'^.}v^^":;';y;'^;;^;':x^;^^H:r-T^^;,;:-<-^ .>■ liii. is -Full priiwn larvBuf r. n< maticida, ml UKnl 20 tim.s. in H-Tr '" A',"-' """ '"•";'"''' *" ""'• «PI>"'-'"«l.v feeding upon the host larva. ..?f.r 1 *' ' ^'"' '*"™ni'': '"•""•' tl"' "«I"U^ emerged about twentv-three days ; f wh -h" 'J"^" ?■•'■■'■ .'***ir'";''- ''''"' '«'»"♦- of the hibernating brood, the eggs ot whuh were deposited in M'ptember, did not emerge until the following Aoril evn"L ntl :'''t. "Vi"" "^ "'';-'""■-:!" "^ 'h-'verwinterinrCoTaZn t ; Vsw ?.' i.i r "'' *?''"r" '""" 'T''*; '**• "''•"•^"•••■- 2.35 mm. in length, more sp^;,^ ;:,;"'>•' ^' "•'' "'"-'^'^ "^ ""'•'-" -K-"tS has the dorsal side li 31 As the development of a single line of the parasites was not followed through- out a complete year, it is not possible to make statements with regard to the num- ber of broods in the year with certainty. I believe, however, that it is safe to make inferences from the observations which were made on material collected in Massachusetts and in Canada. In one batch of cocwms, adults emerged on Octolx'r 9th from cocoons in which eggs had been deposited on September 13th to Itith, from which it would appear that the time of development of a summer brood was about 23 days. It has been found that the females oviposit shortly after emergence, so that no lengthy penod necessarily intervenes between the iievelopment of the broods if the parasite can find healthy cocoons of the sawfly. The prevalence of healthy cocoons of the host would determine the effi- ciency of the parasite. It lias been found in studying the life-history of the host X. erichsunii that the sawfiy larva; may l)ecome full grown and form the cocoons as early as June 12th to June 17th, which would mean that in any year cocoons of that year's sawfly larva" couhl i)e found from the middle of June. Further it has also been found that sawfli«'s will continu.' to emerge from the cocoons of the larvse of the previous year until the end of June, which indicates that there is a supply of the previous year's larva* in their cocoons until the first or sec()n mm. The colour of the body is black; the thorax has metallic dark-green reflections and the abdomen is smooth and shining: the legs are light brown. (For a full specific descrij>ti<»n the original account should be consulted). Diglochin spp. In the Htport of the State Entomologi.>;t of Minni.sota for HH)!)-1<»1(), Mr. A. (1. Huggles states that of several hundred cocoons of X. rfichsonii collected in Minnesota, 10 to 15 per cent, were parasitised by a species of Diglochis. As this appeared to be a parasite of some importance I wished to enquire more closely as to its identity and Mr. Huggles kinilly sent me specimens for examinM- tion which were afterwards submitted to Mr. Brues. Writing in July, 1911, Mr. Brues informed me tliaf the Diolochin agrees well with Hatzeburg's Ptero- mnlua kiugii (see Katzeburg, 1S44) wliich is probably a />»(;/or/ii« like the Minne- sota specimens. There arc at present 873 sjx'cies listed as I'lerumaluH and only /*. omniiora Walker, the type of the genus Diglochis, is ii> yet included in the latter genus which no doubt includes the other species now listed as Pleromalus. ,5| ■ !i *'! n I Hi ■I I 32 Ratieburi bred Pteromalus (Digloehw) klugii in 1841 from the cocoons of V enchsonix coUected in the Grand Duchy of PosJn; I do -xot know T^T^ili quent records of the species having been reared from this host ^ Microcryptus labralis Grav. «„rf,S tTr*'* *'''i'' wj^"* d?«cril,ed by Gravenhorst under the name Phy- O^^euonlabrahs, was first bred in 1909 from A'. encAaonu' collect«« fn ?he EnSh Lak.. Ihstrict Smee that year it has been found each year in naduai?v in thought It might be a hyperparasite. I am of the opinion, howe <«r from it^ beha^^our that .t .. a primary parasite, tiiough, a. ti.e br^X Vx^rimeilt' • Via. l9—yticroerypl)u lnlfa.U Cimv sTre'opin!on'"trTQirIh' "'"'' P^'*""* T"' ^^'- ^'''"K"" (»»'0) is of the Wi^abomi ^' T„ IQ^, • P^f.'-entage of cocoons parasitised by M. labralis mfre out of l' iJS '" "Vo*"'^ '™* °''*''' "^ '^^ ^^^O' *« ^^'^nada from Thiri- centaKe of 16 ' '*'""''' ^^ ^P^^""^"'* "^ '^'- ^"'"•"''^ wore reared i,eing a per- Aplesis nigrocincta Filrster. co,.o.it.s n^ ^Peoniens of this pecuhar wingless icimeumon were reared from ir^ roL- K K «"''^«o"",'n»Ported from Thirimere, England, in 1910 and 1911 It IS reddish-brown m colour with the head, metathorax, pos er or half of dors,li The specimens emerged during the latter half of May 1910 and 1911. Spilocryptus incubilor Strom. on fhT'^JItif^i."',-^'.: "xl ^•''"*'*''' °f ♦'"^ ^•'^■'•'^•'^ with deformed wings emerired Cctlichneumon fuscipes Grav. 25th'Anrif'*lQrn''r"' °^ V"' ^''**'". '*"■«« ^"^"^ ^•"'""••''d species emerged on ^5th April, 1910, from material received from Thirimere, England. Gratichneumon annulator Fab. MorlVimerged™ol^1th"M:i''to', r'i'''^ ^"' '^''" determined by Mr. Claude lYioriej emerged on 18th May, 1911, from cocoons from Thirimere, England. Hmmmm 1910 33 CryjUtu minator Grav. A single specimen was reared from Thirlmere, En„ md, cocoons in May, Perilampus sp. », , ^^y tT'""/!' ^I- JY- ^- ^^'^'' '" •'^'"■K'^ °^ *'»*' Cl'P^y Moth Para-site Laboratory, Melrose Highlands, Mass. collected some cocoons of N. erichsonii in September 1909, in the fori'st near Lake Nebagamon, Wisconsin. One of these cocoons was opened in March, 1910, by Mr. H. E. Smith who discovered the minute first stage larva of the "planidium" type attached externally to the sawfly larva Mr. Fiske, who kmdly sent me the specimen, informs me that it is quite similar to the planidium of Perilampus hyalinus Say, in size and structure but very different in structural detail. This difference I have since confirmed from Mr. Smith's description' of P. hyalinus. This minute larva is almost invisible to the unaided eye, being alH)ut three-tenths of a millimetre (less than one eight- ieth of an inch) in length. P. hyalinus is a hyp<'rparasite or secondary parasite of the hymenopterous and dipterous (tachinid) parasites of the fall webworm Hyphantria textor Harris. Another species of Perilampus, namely P. caprinus Forster, has been reared in Massachusetts from puparia of the tachinid parasites of the gipsy and brown-tail moths. Periliasus filicornis. This species of hyinenopteron is given by Cameron (1885) as a parasite of AT. erichsonn. Bnschkc recorded /'. lulescens as a parasite of AT. erichsonii. Mlcro(ja.iter sp. Lintner (1885) states: "The larvae collected were remarkably free from parasitic attacks. A single small white cocoon apparently of a Microgastcr was obtained from a half-grown example." ' DlPTKROUS PARASITES — TacHINIDA:. Frontina (Masicera) knthredinidurum Townsend. Fio. 20— Larva of tachinid fly, probably Ezoritln ap. Two specimens of the tachinid were received from Mr. (lordon Leavitt, St. John, N.B. They had been reared by him from A^^. erichsonii in 1910, and were determined by Mr. J. D. Tothill of this Division. This species was dc- seribetl by Townsend' from a single specimen reared by Mr. W. H. Harrington, Ottawa, from a s.iwfly larva, the species of sawfly not being stated, but it may have been iV. erichsonii, which is common about Ottawa. The parasite issued in July. 'Smirt, H. S. "The Chalcidoid Rcnus Perilampua and iU relations to the problem of Paratita Introduction. Part IV of Technical ResuIU from the Oipny Moth Paraaita Laboratory. BuU. So. 1$, iteh. Str., Bur. Ent. U.S. Dvpt. Agr., IBIi. 'Tomurml, C. H. T. 'The North American Gcner ' Calyptrate MuMida. Paper IV Saroo- hacida and Muacida." Tniu. Amtr. Ent. Soc Kof, K, >. ISS-tU, tS»l. 23644—3 ft ^1 iV Exorisla crinita Rond. Each year from 1909 to 1911 specimens of this species have been reared by t'^TCt^TeTa/v^^^^^^^^^^ ^"«- -«* '* '« -* '™P-b"»^5"e Exorista sp. Mr. Mangan has sent me for determination four Tachinids three male and St Mr"' 7 D^ tTh-h' 1 *'°*"''"'' ^°'^-*r» •'^ Crummock like, Cuilandl *jig Mr J. D. Tothiil has exammcd them and finds them to be either identical with or r'ose to Exorista alacris Meig. COLKOPTEKA. In a letter to me of July 28th, 1910, Mr. W. F. Fiske says:-" I also found two larv« of a small parasitic beetle, apparently either a (Irid or TmaosS One of these lary^ was dead and mouldy and the other hLl St the 7rmS cocoon and spun a rough silken cocoon of its own. This L the first parSic beetle which I have ever seen attacking sawfly larva." Parasitic ACARI. „„n ^" if""*/. *'*}'•''," ''^'■Ki' numl)cr of female sawflios emereine from cocoons f„\V L 1™*^' **''"^^^«'">fl to be infested with small reddish brown mites Hlrfi^-7:r' '*^'^''^ ^''"'" ^'"'^ «"»>mitted to Mr. A. D. Michael who kSlv ident fied them as hypopi of HMostoma rosln^serratum. Although they are E Jisp'r^r" ''"' attachment to the sawfly is for the purpose of secUg PROBABLE HYPERPARA8ITES J AND DOUBTFUL PARASITES crichsonii material. REARED FROM A'. In the study of parasites it is very fror,uently most difl^cult to decide whether Heiniteks nccator Gray. Anacharis typica Walker. 35 mined for me by Mr. Claude Morley. Handlirsch recordH the rearing of this species from the neuropteron Hemerobixis nerowtua Fabr. The living larvK measured alx>ut 3 mm. in length. FiffHes sp. Two specimens were reared in 1910 from material from Cumberland, Eng. These insects are usually parasitic upon diptera. They may have been para- sitic on tachinid para-sites or upon .some unnoticed dipterous pupse. Microplitis sp. A single female braconid referred to this genus by Mr. Claude Morley was reared from English cocoons (Cumberland) on May 10, 1911. PREDACEOUS INSECT. Hemiptera: Penlatomidct. Podisua modeslus Dallas. This predaceous or blood-sucking bug has been frequently found feeding upon the larvse of N. erichsonii. Fletcher found it in 1884 destroying the sawfly larvae at Brome, Que. Lintner (1889) records it as a predaceous enemy of N. erichsonii. He found it in July feeding oi. the sawfly larvae and remarks that: "In fastening upon its prey, in almost every instance observed its probosis was inserted near the anal end of th? larva." Packard says: " We also noted several bugs, a species of Podims, near the common spinosus, preying upon the fully grown worms; it ascends the tree and pierces the worm with its beak, carrying it down the tree and sucking its blood, rendering it lifeless." The species was no doubt P. modestus which closely resembles the common P. maculivenlris Say (formerly P. spinosus Dall.) F;o "^l — Pmlaceoua Uuk: I'uditut modetliu Dall. P. modeslus (Fig. 21) is common throughout Canada and the north-eastern United States. The collections of the Division of Entomology contain specimens from Quebec, Ontario, Manitoba and British Columbia; Van Duzee .states that it occurs as far west as Dakota, Nebraska, Colorado and Montana in the United States. It measures about four-tenths of an inch in length. Its colour is yellow- ish-brown to dusky brown with very fine darker brown markings. The sides of the shield-like prothorax are produced into blunt spines. This species may be distinguished from P. maculivenlris by its slightly smaller iiie, paler colour and by the possession of a short ventral spine. ! iii^ Parasitic Fungus. Itaria farinota (Dicks) Fr. (Plato I. Fi«. 4; PUto II. Fif. 21) thP WK^J^l^*"'**'" i*»?l?'°8 ™y investigations on N. erichsonii it was found that cw-tfycepa p-oup. This fungus appeared in the form of white natches on thi. wrb^HeT^fitTh!'K^ "^''l'^*^' Hporophores of the conTdi^l Sm. "a H ToTooS wSl r L„Jf Tff °^^ *^* "*'" ■ ' hiJ)ernation and to spin their roeoons would become infected if the spores of this funmis were in the anil ffi™ A"Die"cnf'r'"!,°"t''{.''^>*r" ^'«" *« testinr^heTali^ty'of S belief. A piece of ground which continued use had shown to be uninfected with v^n. fLu'i ^""*^"' was chosen in a region where the sawfly d^fnot occurTnd young larch trees were planted. A large number of larva were placed on these arches and the ground round the ba.ses of the young trees was infSd bv d'^ tributi iig specially infected soil and litter containing the spores Unfortunatell TstZiTnX^ '^' r?" «'°"Pu.°^ '"•^''^ «»d my r^emovaHo Canada p^ev^^^^^^^^ wif ^ conclusion to this experiment. prevent (i „^J!-*- " *^°«*?"? o^ ^- erichsonii were received from finirland in 1910 a certain ?o r, Pn '"^ "^^- ^*i? *^« '""8"^ ^°« accordingly hand^ some of t^m Lfe^ioS ^Th^e ^:^irJ?l^'''''''r'^'l *^^* »>« »•«»>* 'tudrth^ problem S mieciion. ihe results of these studies have since been nnlili.ho^i \i. the'r: f "*'^^ **•? ^"¥"«' "^''^ ^^^^« cultivated i^l^Isanafa^sa md tL^^ jHnK"« was ound on cocoons which were collected byTe near^?awa Xnwi^r*""* T^T'' iJ ^^^ n««^««'*'y to decide was whether uTi.s fungus Z powing saprophytically on the sawfly cocoons, that is, growing on thfslw'V larvae which had died from other cau.ses, or whether it was?p3te and cabbie nrovinlHTo*, ♦K*"°°"'" ^'^^T' :« *" *^^ ^*«"« 'covered cocoons which had been mosst ihiI^iP"'P*''^' -^ ^''^'^ experiments) "were placed together with thS moss in which they were imported from England into a flat glass Ssh The ThTcarwrSlSthe'dLr"i"'"'^.''' PTl"'^^ *»>« moistu're^ltStorTly 99 Hat? „ -5 I , ''*''' Vnder ordmary laboratory temperature In about nrifeii^oT'"*^™^\'>"^'^*'*y «^ sporophores of the iXa were Produced t^.e'^^«ai^ M '°^T' '''"^"K **'*' *»»'*« Patches of the fungusTere p'aced in were H?«L f^H ''«1" *?»««•=* emerged from these cocoons. Some of the cocr oi" yel owl^h aduft Th^r"'%"!l'^ ^''' ^"""•^ *° ''°»^'"" « blackened or dir"; further I then nW • '^T''*,^'* T?°"/ ^^''^ '•''P''*^*'*' ^^^ ♦»>« /.,«„« developed iZi \:- u u "bta'ned a handful of cocoons which were carefullv examined "Experiment B.— The same number of coc ins werp na»rl ti,„ placed together with infected moss and co'rn^ ZS'l'^^a.^S'^.r. 37 small breeder. After ten clays, six adults and six parasites were observed and were left confined in the cage. One of the first peculiar symptoms obJrVetHn these cocoons was a darkenmg in colour of 16 of them; the colour of thTnorma" cocoons being light chocolate, while in these ca-ses the colour was of a pronoSS dull chocolate tmge Four more adults em-rged on subsequent occa^K Although no signs of /.^„ a were then noticeable on the darkening COCOONS of them were di^^sected and microscopically xamined. Two of the examS cocoons showed the interior walls lined with white fungus hypha^; othere slS furtgal hyph«e m the dead adult's body. Uter on wWte fluffy pktch«. occurTed externa ly rather suddenly on most of the remaining co.oons. ' From the apS- ance of these fungous growths it was evide- t that they were formed hy the I^ria About two month.s «fter Ijeginning the :periments, the fungi formed the wX known forked sporonhores and the microscopical chara.ters proved the fuSs to be /«ar.a. Spores had been produced abundantly at very e^rly stages and no i7e stai^/?hT^'''"'?'"''l1'''™"'^'T*.*''''*^««« When about thr*^,,;ths after starting this exiM.ninent I examined the interior of the cage again, 1 found oroniesofnZi'"'^!:'^'''""^ ""*' throughout the layer studdedlith fine whTsh colonies of fungi. These were examined and found to \>e small colonies of Isaria These colonies remain up t.. date very minute, but never disappeared. New ones constantly appeared aiul at present the moss is peculiarly stu.hled all over with minute /aana colonies These colonies having no suppl/of cong ^1 S remained small and were of course <.f starved app^ .ranee. I next se, rateTa few and transferrecl them to a petri dish containing nutrient gelatine Here they made three days' rapid growth and no doubt would have covered in the wl c . ;;iyt ' ^''"'V"'-^"'-^' '"< f«^ the appearance of gelatine liquifying bacteria reSpf.lv fh^/'^rr"""" ""' *" ""^ observation. Nevertheless, it w*s proved rejK'atedly that the fungus spots consisted of haria farinom and no other. It ^hL^'^Tv!''^ }" ™^•^''* ?r^' throughout, these r-iperiments, was I able to imrr.n; .''^^""'^'=''''^'''T'""'"f ^"^' "^''^^ ^»""n«n ^milds. Several important^ conclusions may be drawn from these experiments : „„ I-.-" *^'''*"*<''' that the cocoons used in experiments A and B were in eoual n^li^Zt" ^f/' ^^''' ^^^ ^''^•*'. '^ «=«n'=«n»ed, it is shown from the greS iXti on of a r„r^ °' P'""'''^*''' T*'''^'"^ ^^'"" "'«'' (exr.eriment A) and fr^ the farfnn^ni* I '^^ proportion of cocoous in experiment B that the fungus Isaria fannosa is truly parasitic on larch sawfly cocoons. one J:2t^ T'k*'"^ that spore infection of the cocoons had taken place. On S;ain~i„i:t^:"'"*' '^' "^^'^'=*'"" "^ *'- ^'J^'*^- '^^y ^'-d rapidly but a con2;hI5hl!Tn^./''''"rf-'^"'''"''*'' ■« capable of vegetating saprophytically for L?i?f; . *^!*' ?^ ^'"•'' ProvKkMl sufficient moi.sture is available. The coalitions."" ' " ' "' """"^^ °^ "^'^ ^'^•'^ °*'^"^"' ^^^« ''•'°«« t« ""t"'"' the Dun^lini"P rv ^'''r M|P^"P^'yti«- mode of life there remains little doubt that the pupaUng h.rvae of the larch sjiwfly infect themselves when taking to the S of X''"".''"";- ^^" *'"'1"'"-^ ''^"''^''^ '"^ the mo.ss appeared aU,u? the t?rl„ f ^ ami continued to show up to the end of September, during which time, of course, the pupation' of the 'arch sawfly takes place in nature " tn.iiJ '"^ve to recortl .some observ. ions on another experiment undertaken sDotTnr/,"^^ f ' '* " ^^1'^^^ *° '?^''* ^"'"^ ^^^y 'i^'^lts ^id cocoons with ThZ^lJ^ZT ^r'"?,''"r '■"'*"'"^^- *"^ ^^'^ P^^P"^'-- -^ fl'^t glass dish containing thn.?!? t?^ ^^ sterilized on three successive days in an hot air sterilizer. Al- suKninH™"** T*"*? '"T"? •" T'""r '* ^*'" retained satisfactorily moisture in this annl^, introduced. 1 then piacetl a number of living adults and cocoons m this apparatu-s and dusttnl the whole with spores that had been produced in apure culture of harm. The living adults had all died after thrJ^ day.s and M il none of those (11) emerging from the cocoons rontraeted the fungous disease. After 21 days no more adults emergef these, nine eventually developed the typical Isaria and the moss also began to be covered with numerous Isaria colonies. This experiment confirms my other oliservations and al.so indicates that the disease may \n> artificially introduced even at so late a stage in the development of the larch sawfly. Infection takes place in nature, no doubt, much earlier." "Although none of my experiments were made under strictly natural conditions, that is to say in the open air, y ^ the observation that the fungus Isaria is regularly fmuul year after year ui r larch tn-es when once it has been found, may indicate that the results obv..ned really closely show what takes place in nature." The above results and observations are confirmatory of my belief and observations as to the method of infection. They also indicate that the fungus is an important factor in the control of the disease, which is supported by my own and Mr. Mangan's observations under forest conditions. In certain ca.ses the number of co<-oons attacked has l>een as high as twenty-five per cent. Such a percentage of infection was oljserved by me in one locality in Cumberland in January, 1 -i The adoption of any prai,..able measures against a pest of the nature of the larch sjiwfly when it is widely spread ane made for the presence jf the diaracteristic larva? or their green excrement "pellets" which can often be found when the larvffi are beyond reach or sight. It may be iM)ssil.le to control or eradicate the pest in its earlier stages when a few trees only are attacked. Plnnting. In replanting or afforesting areas pure stands of larch should be avoided if possible. It has been olwerved that pure stands of larch are injured most by the depredations of the larvae. In my first Report to the Manchester t orporation Waterworks Committee (August 1907) the following suggestion was made:— "In order to minimise the attack of the larc'u Chermes which is often a source of trouble to larch and spruce, I would suggest that in future the trees be planted in belts as far as possible rather than in a mixed manner, alternating larch and spruce with a belt of hard wood. This would les.sen the risk of all the larches in a plantation being attacked by any peat similar to the one under consideration. If larch and spruce were divided by a l)elt of hardwood they would he less likely to suffer from the attacks of the injurious Chermes. This method of planting trees in bdts has also the .advantage of preventing to a great extent, th<' spread of fire should it break out. " As a result of suKsequent recomni.'ndations of Dr. Fisher the Manchester Corporation are not planting pure larcr. but mixtures. Annand (1910) makes .similar suggestions with regard to avouhng the formation of pure larch plantations and the planting of isolation belts. He also recommends the underplanting of young plantations of pure larcli with .shadcH-ntluring species to check the growth of mo.sses and grasses indispensable to the safety of the cocoons. 39 THE ENCOURAUEMENT AND PROTEJTION OF BIRDH. Thr importance of a plrntiful supply of inMottivorous hir.ls is (H-rominit rerognisetl in certain Luropoan countries and their encouraKonient is a necessary adjunct of any system of forest protection, where the al.undanco of insecti- vorous bird hfe IS below normal. The method of making the nesting boxes has been descrd,«l already (p 23). The distribution of thcCe should Ik- supple- mented by the erection of "f.^Kl houses" in different pla.es. The He.lian food house, .leyised by Baron von Berleps.h, is the most ...nvenienf form and can »>«,ff ' >■ i'7;;'-d hy any one at very littl.- -ost. A numln-r of these "food- houses (Platplll, Fir 24) have Jn-en erecte,! on the Kstateof the MancheX ( orporation Waterworks m ("uml)crland (England) and arc proving to \w of great value. Their method of construction and other information relating to tl-e encouragement of birds is given by Hicsemann whose valuable book has been translated.' Remedial Measures. The measures which may \k adopted for the control and eradication of the larch sawfly will vary according to the extent and character of the infestation Measures practicable for single or small collections of trees whose value is due to their ornamental character are not, ir manv cases, practicable- on a large scale in the plantation or forest, as experiments earlv in this investigation showed In fact rcnacdial measures of an artificial nature are practical)le onlv in the ca.se of sma I collections of trees or in plantations <,f a limited area. In the forest the only remedial measures which will offer any hop.- of success are those of aiding natural means of prevention and control. Spraying. Where individual or small groups of ornamental trees or planta- tions of young trees are attacked, the spraying of the trees wth an arsenical poisim t«» loll the larvse is practicable and may be adopte.1. In one ot' mv previous reports (1907) spraying with a .solution of arsenite of copper was rctinunended tor ttie protection of the plantations of young trees in Cumberland. This was used in the proportion of 1 lb. of copper arsenite to aix.ut 130 gallons of water- one pound of flour was added to make the solution more adhesive to the foliage, i aris green in the proportion of one-quarter pound to fortv gallons of water or lead arsenate in the proportion of two pounds to forU- gallons of water may be^ used, the lead arsenate being preferable to other arsenical insecti- cides In 1909 on the Estate of the Manchester Corporation at Thirlmere, t umberland, England, aliout forty acres of young trees reaching a height of about eight feet were sprayed with the copper arsenite and flour at a cost of atjout $1.48, or SIX shillings and one penny, per acre, and by this means the de- tonation of the young trees was prevented. •11 7^^ *'"®^® should be sprayed when the larva> are discoyere III 41 goveraing their increase and their relations to their ho j shall be in a better position to determine whether, and to what extent, the parasitic means of con- trol can be utilized in obtaining control of extensive outbreaks. An attempt is being made at the present time to introduce the ichneumon parasite Meaoleius Unthredinis from the counties of Cumberland and West- moreland, England, into Canada. Small quantities of the parasites were bred out from English cocoons in 1910 and ICil and liberated in Canada. In 1910, several hundred specimens of M. tenlhredinis were liberated in the grounds of the Central Experimental Farm, Ottawa, and a number were liberated in the Algonquin Park, Ont. In 1911, English cocoons of the sawfly infested with M. terUhr^inis were distributed in the following localities: near Quebec city, near St. Agathe, Que.; in Algonquin Park, Ont.; near Point Platon, Lotbiniere Co., Que. (see page 27)-. In addition, further specimens were liberated at Ottawa and a box of cocoons was sent to Mr. R. H. Pettit, State Entomologist of Michigan, who is endeavouring to colonise the parasites in that state. Unfortunately the percentage of the cocoons containing the parasite M. tenthredinis in 1911, was not so great as in previous years. With a view to making further importations of cocoons from England ir»f<»sted with M. tenthredinis, I visited the Lake District in England in January, 1912. A locality was found near Grasmere, Westmore- land, where a considerable percentage of the hibernating larvae were found on dissection to be parasitised. Through the kindness of Sir William Ascroft, the owner of the infested locality, and the co-operation of the Manchester Water- works Committee, whose chairman, the late Sir Bosdin Leech, had been in- terested in this matter since the insect first appeared in the district, Mr. A. W. B. Edwards, the forester of the Manchester Corporation, has superintended the collection of infested cocoons for shipment to Canada. The cocoons were shipped packed in moss and litter in ten seven-pound biscuit tins, the whole being shipped in a single crate. This method of shipping has proved successful, if arrangements are made to prevent over-heating en route. An attempt is now being made to establish the parasite M. tenlhredinis in the Riding Mountain Forest Reserve in Manitoba, where the sawfly is abundant at the present time. Time only will show whether the colonisation of the parasites has been successful, as it s hoped and anticipated that it will be. Not until the parasitic enemies of the larch sawfly have become sufficiently widespread and abundant to successfully cope with the unusual increase in the numbers of the sawfly in any particular locality, as appears tp be the case in Europe, will outbreaks cease to have the serious consequences which have been experienced in the pas* in Canada and the United States. THE ECONOMIC VALUE OF THE LARCH. The value of the larch or tamarack for the purposes of afforestation and timber production is often lost sight of or minimised in Canada, owing to the fact that we have at present an abundance of those species of forest trees producing timber of a higher general commercial value. In reply to my request for some information as to the uses of the larch in Canada, Mr. R. H. Campbell, Director of the Forestrj' Branch of the Depart- ment of the Interior, has kindly given me the following information. One of the most important uses of the larch in Canada is for railway ties. The wood lasts well in contact with the ground. Owing to the fact that it ho.Js a spike well it is used extensively on curves in railway lines. It is also used in ship- building for ship's timber and knees, particularly for the latter purpose. When wooden ship-building was in a flourishing condition in Canada, large quantities of larch were used for that purpose, but with the decline of the industry the use of th(> larch has greatly diminished. The timber is also used for fences, telegraph poles and for mining timbers. It is sometimes sawn into lumber, esDeciallv 23644—4 42 in the north-west and is used for lath and shingles when better woods are not readily available. To a small extent it is employed in the manufacture of cars, agricultural implements and cheap furniture. In speaking of the larch in the Riding Mountain Forest Reserve, Manitoba, Mr. J. R. Dickson' states: "Owing to the strength of this timbf r, its durability in contact with the ground combined with its great length and small taper, it is a very valuable species for posts, rafters, fencing and construction work gener- ally. Moreover, it is the favourite and highest priced fuel wood on the local markets. But although for these reasons it is a tree of vast utility to the settler, yet to the mill man it is a "light bodied" tree, normally of too small a diameter to cut into profitable saw material. For this reason larch should not be favoured over white spruce on good soils, but for all the more poorly drained areas it is the species to be favoured." The American larch is said to be an intolerant species I 1 and is ne: 'ly always found in either pure stands of trees of similar age or as the dominant tree in a mixture. As we have seen, the sawfly prefers the European Larch (Larix europaea) to the native North American species {Larix americana.) The European larch, however, is probably preferable for reforestation purposes. In a valuable paper "Reforestation of the Natural Forests"* Mr. W. T. Cox states: "European larch is a desirable tree for commercial planting in the United States. It is . a rapid gr^^wer and produces heavy, hard, strong, flexible and very durable wood. It has been successfully grown in the United States from New England to South Dakota and South to Kansas and Virginia, to which general region it is adapted for coniiiinrcial planting. It does well in eastern AVashington also. European larch is rather fastidious in regard to soil, requiring one that is deep, light, fresh and well-drained and does not flourish in swamps as does the American larch. It may be established by direct seeding, or by planting two-year-old seedlings or transplants from the nursery. It should be sown or planted in mixture with other species rather than pure, in a proportion of one larch to two or more trees of other species, the trees being spaced four to six feet apart each way. " In the arboretum of the Central Experimental Farm, Ottawa, both the European larch planted in 1889 and the Siberian larch planted in 1896 have been found hardy and able to stand the severe winters. ■"The Riding Mountain Forest Reserve." Bull. .Vo, 8, Foratry Braxeh, Dept. Interior, Cinwda, it pp. 18 p(. laOD. 'BM. No. 98. Forett Service, U.S. Dept. Agriculture, p. SS. i! not ?ar8, oba, ility it is ner- ocal tier, leter iired I the ?cies the aea) Tch, iper >ean [t is able land gion ^on that does ting a or one I six the lave I pp.