in 4 | ih 4 iv - ae 1 i ' 7 { at h y : 1 ‘ i, ; j = o a ~ i : 1 —— w F = ‘ ‘ 7 ; A + i 4 j i SEMICENTENNIAL PUBLICATIONS OF THE UNIVERSITY OF CALIFORNIA 1868-1918 MISCELLANEOUS STUDIES IN AGRICULTURE AND BIOLOGY BERKELEY CONTENTS : PAGES A Synopsis of the Aphididae of California, by Albert TE SIS GEST ee se 5 ee 1-221 Mutation in Matthiola, by Howard B. Frost... 223-333 Ocean Temperatures, their Relation to Solar Radiation and Oceanic Cireulation, by George F. McEwen........ 335-421 Changes in the Chemical Composition of Grapes during Ripening, by F. T. Bioletti, W. V. Cruess, and H. Davi A SYNOPSIS OF THE APHIDIDAE OF CALIFORNIA BY ALBERT F. SWAIN [University of California Publications in Entomology, Vol. 3, No. 1, pp. 1-221, pls. 1-17] A SYNOPSIS OF THE APHIDIDAE OF CALIFORNIA BY ALBERT F. SWAIN CONTENTS PAGE VEST OG a CO) 1 ane ee ne Boas 22a 1 Mises casa essere 2 (CUPS FSWU TCE ESA © a ep oe a 4 TBS AOE CERT EE NOY 00 78 eee ee eee er EEE 2 aio) PESTO Ch y pate eens Seen cat See earn eee ae 8 Economic considerations 9 Syl SS es acne scc cet ecco ntsc eter ae ct wcscb gens nacathesvcenscoeaee fcesase secccectee BA en sere 10 TOENTETUD A ING 0) OCG LG EEN) oe cs ea aR Ae a nS Se RR Ee 10 RSH ener a a PeNG 6} AWS OEE ce Oe ee REE RE Cree Eee Re eer 11 Group Callipterina —... es 12 Tribe Phylaphidini 12 Tribe Callipterini 16 Tribe Chaitophorini 2 (Gir oP Bt WEE gear te nee eee So BR Ree Rope 39 Tribe Pterocommini . 39 H Bier aXe} d DYe kA 01 0 OW ere RE ee SO 8 ee 43 CGAY N Fo)’ SeNyo) Pa bees Yi ene Soe era re a eee = Ce PEE oe - of HE Fer ae WN EY Oat OVS HN a) COHAN, 0 ce See Sees Se SAE soe 5S eee cc eRe SS SE ee SSE eae Eee 52 BUNYSUESCSMPAN Sp) EL CU TEL ee cee a eee ec aE ne ee eer 87 Sab Lair yap Crip On so eee see oso enone aera cnc eee cee sc eee arene rans 138 (Coney Ne) LENO peg NANG TIES), cae Seppe eer anh crest eee ees RoR Ree ees Freee 139 Groupee erm pia prance eee ane ena seeteee cose onthe ener Stet a sientoeee 140 Grom Sch. ore wean a ene re eee eee Fe See Sees et ese 147 Group Vacunina .................. Pe Re a i dr ee 150 Subfamitlya (Phylloxerin ae. eos aaceetencsc creep ocean sec asee sec cas ate pec es eae ecsesace 151 (Group) Cherm Sia oa ca ns ace ee ce den wee na naecerc ce neecerssnaedaceres 151 Group: Phylloxerimay q22-cceceeccnc va oid ceeccewenes = fan ctoacestosesec-socanss arercueconutecsoaucute 152 2 MISCELLANEOUS STUDIES PAGE Appendix 1. Keys to the genera and tribes of Aphididae; a translation from DBE Vian er GOO 6 asa 2 cca aa wan accent oe eee eee ee en 154 Appendix 2. Host plant list —... pee GY) INONOLESOOHE), Sener ae lye} Explanation of plates -.... . 180 Index to genera, ‘and species ye ce ae ea oan 215 INTRODUCTION In recent years considerable attention has been paid to the Aphididae in the United States, and in Europe as well, and a large amount of literature is the result. In California, W. T. Clarke was the first to make any systematic studies of these insects and his paper, published in 1903, embodies the results of these studies. He listed forty-three species, ten of which were described as new. Two or three of his new species are known at present, but the remainder are unknown. Unfortunately his collection was destroyed in the earth- quake of April, 1906, so now it is practically impossible to determine his new species -with any degree of accuracy. Following this, there was a period of six years in which there were no publications con- cerning the Aphididae of California, except some economic bulletins from the Experiment Station. In 1909, both E. O. Essig and W. M. Davidson published the results of their earlier studies. Since then both have added papers oceasionally. During 1912 and shortly before, Harold Morrison made an extensive study of the species in the vicinity of Stanford University. He has kindly placed a report of his studies in the author’s hands, with permission to publish the records in this paper. The author has been studying the Californian species con- tinuously since 1914. At present there are about one hundred and eighty species known to oeeur in California. This number will undoubtedly be greatly inereased as further studies are made, since to date only a compara- tively small part of the state has been covered by collectors. Very extensive collections have been made in Ventura County and in the vicinity of Pomona College, Los Angeles ‘County, by Essig. The San Francisco Bay region, particularly in the vicinity of the University of California and Stanford University, has been carefully surveyed for aphids, collections having been made by Clarke, Davidson, Essig, Morrison, Ferris, and the author. Davidson, Clarke, and Essig have made a few observations in the Sacramento Valley, particularly in Placer and Sacramento counties. The author made a number of A SYNOPSIS OF THE APHIDIDAE 3 observations in the vicinity of Fresno during May and June, 1915, and more or less extensive observations and collections during 1916 and 1917 in San Diego, Riverside, Orange, Los Angeles, and San Bernar- dino counties. In addition to these, reports come to the College of Agriculture occasionally from the State Insectary and the various county horticultural commissioners. A summary of the above state- ments shows that extensive collecting has been done only in the territory adjacent to San Francisco Bay, and throughout southern California. The whole northern half of the state, the great interior valleys of the Sacramento and San Joaquin rivers, and the desert sections of the southeastern part of the state are as yet unexplored. Undoubtedly many interesting species will be found in these parts. The author wishes to express his appreciation of the aid rendered by various people during the past three years of study. To Harold Morrison of the Federal Board of Horticulture is due especial thanks for his assistance during the early part of the author’s study, for his collection notes, and for the use of his extensive collections of Stanford University vicinity and Indiana; to E. O. Essig of the University of California for his continuous advice and assistance, for the use of his large collections of Californian species, and for the reading of this manuseript; to W. M. Davidson of the Bureau of Entomology, U. S. Department of Agriculture, for his many notes and deter- minations and for the use of his collection; to A. C. Baker, J. J. Davis, C. P. Gillette, A. S. Maxson, E. M. Patch, and H. F. Wilson for their many determinations and suggestions; to R. W. Doane of Stanford University for the permission to work over his collection of Utah aphids and for permitting his students to use the keys included in this paper, thereby finding the weak points in the keys; and finally to G. F. Ferris of Stanford University for collections and advice. In this paper the author has brought together all the present records of California Aphididae. He has included keys for the determination of the subfamilies, groups, genera, and species, together with such illustrations as are necessary for an understanding of the keys. The discussion of each species includes a bibliography of the California literature (exclusive of the merely economic and popular), together with a citation of the original description and the best available description, a list of host plants and localities, and a dis- cussion of the synonomy, life history, and habits so far as they are known. The descriptions of certain species are not readily accessible and of others not at all adequate. Such species have been redeseribed 4 MISCELLANEOUS STUDIES by the author in so far as it was possible to obtain specimens. Inci- dentally it may be stated that the author has personally collected by far the larger number of the species recorded in this paper. In other cases the fact is noted. A host plant index (appendix 2) is also included. The system of classification followed is the one most generally accepted by American aphidologists at the present time. The keys to the species have been formulated by the author, those to the genera and higher groups have to a large extent been adapted from other workers, particularly Wilson and Essig (Aphidinae), Borner (Phyl- loxerinae), and Tullgren (Pemphiginae). The papers of Baker, Clarke, Davidson, Davis, Essig, Gillette, Oestlund, Patch, Pergande, Williams, Wilson, and other American aphidologists have been found invaluable. Of the works of the European aphidologists, those of Borner, Buckton, Del Guercio, Koch, Mordwilko, Tullgren, and Van der Goot have been in constant use. The classification suggested by Van der Goot (‘‘Zur Systematik der Aphiden,’’ in Tijdschrift voor Entomologie, vol. 56, p. 1913) has proved interesting, and although the author has not felt at liberty to accept it in full, a translation of 9 his keys to the groups and genera has been included herewith (appen- dix 1), which, it is hoped, will be of assistance in the making of determinations. CLASSIFICATION The Aphididae belong to the order Homoptera, being closely related to the Psyllidae, or jumping plant lice, the Aleyrodidae, or white flies, and the Coccidae, or seale insects. The Aphididae, or plant lice, are small, soft-bodied insects, ranging from less than one to five or six millimeters in length. Typically there are four forms: the apterous and the alate viviparous females, and the sexual forms, the oviparous females and the males. There is considerable variation from the above in different groups and species, as will be pointed out under the discussions of the various species. The alate viviparous females are the individuals most commonly taken by the collector and the ones that usually show the best characters for determinations. In the keys in this paper all characters refer to the alate viviparous females (the alates) unless otherwise mentioned. A SYNOPSIS OF THE APHIDIDAE EXTERNAL ANATOMY The body? consists typically of three divisions, the head, thorax, and abdomen. In the apterous forms the mesothorax and metathorax are closely fused with the abdomen, while the prothorax and head are distinct. In the alate forms the mesothorax and metathorax are fused together and appear as a distinct division, the body appearing to consist of four divisions, viz., the head, the prothorax, the meso- thorax and metathorax, and the abdomen. The head bears a pair of compound eyes, usually three ocelli, a pair of three to six jointed antennae, and the beak: Of these, the antennae show the best characters for determinations, not only of species but of higher groups. They are either mounted on distinct tubercles (Macrosiphini, certain Callipterini) or appear to arise from the front of the head. They consist of from three to six segments, the terminal one of which is usually provided with a projection or spur. They are six-segmented in the Aphidinae (except Essigella and Cerosipha), five- or six-segmented in the Pemphiginae (except in the stem mothers of certain genera), and three-segmented in the Phyl- loxerinae (except in Chermisina, in which the alate forms have five- segmented and the sexual forms four-segmented antennae). The spur of the terminal segment may be equal to or longer than the segment (Aphidinae, in the Macrosiphini it attains its greatest length, often being as much as ten times the length of the base) ; it may be merely a short thumblike process (Pemphiginae, Lachnini, and cer- tain Callipterini) ; or it may be apparently lacking (Phylloxerinae). The two basal segments are always short, and quite regular in all species. The remaining segments show the greatest diversity, par- ticularly in number, size, and shape. Sensoria are always present on some of the segments. There is one primary sensorium always present at the distal end of the terminal segment, and when the antennae con- sist of more than three segments, one also at the distal end of the penultimate segment. These sensoria are fairly large and clear (some- times furnished with a hairy fringe) and are more or less cireular. The accessory sensoria are a group of small indistinct sensoria, which number from three to six, and which are located in close proximity 1 For a fuller discussion of the external characters consult the following papers: Vickerey, R. A., A comparative study of the external anatomy of plant lice, 12th Rept. Minnesota State Entomologist 1908; Sanborn, C. E., Kansas Aphididae, Kansas Univ. Sci. Bull., vol. 3, 1904; Mordwilko, Alexander, Keys to the groups and genera of the Aphididae, Ann. Mus. Zool. Imp. Acad. Sci. St. Petersburg, vol. 13, pp. 362-364, 1908. 6 MISCELLANEOUS STUDIES to the primary sensorium on the terminal segment. Secondary sen- soria are usually present in the alate forms, but oftentimes absent in the apterae of certain species. When present they are always on the third segment, but in antennae consisting of five or six segments, they may be present upon the fourth, fifth, and even sixth segments. In the Pemphiginae they are arch-like or half rings, or form complete rings about the segments. In the Aphidinae they are cireular, oval, or transversely linear, but are never rings or half rings. The shape and number vary considerably, and are of specific importance. The number may vary from as few as three or four (Myzocallis maureri Swain), to as many as forty to fifty on the third segment, and many also on the fourth and fifth (Myzus braggii Gillette). Unfortunately these highly important characters were overlooked or not taken into consideration by the earlier workers. The beak is four-jomted and seems to arise from between the fore legs. It is always present (except in the sexes of certain of the Phylloxerinae), but is seldom of specific importance (except to distinguish Aphis bakeri Cowen from Aphis senecio Swain, and in certain of the Lachini). It may be very short, as in Aphis bakeri Cowen, where it reaches only slightly beyond the first coxa, or it may be very long as in Stomaphis, where it is from one and one-half to two times as long as the body. In leaf-feeding species it is usually short, while in bark-feeding forms it is longer. This is naturally necessary, for those that live on thick bark must have a longer beak in order to reach through to the plant juices. The thorax consists of three divisions, the last two of which are usually more or less fused together, and considered as one; the two divisions being called, in this paper, the prothorax and the thorax. On the lateral margins of the prothorax there is sometimes a pair of small tubercles. These are not present in all species, however, and they differ considerably in size in the various species. There are three pairs of fairly long and slender legs (except in Phylloxerinae. where the legs are greatly atrophied, approaching those of the Coccinae in size). Typically the legs consist of four joints, the coxa, the femora, the tibia, and the tarsus. In some genera the tarsi may be atrophied (Atarsos, Mastapoda). The comparative lengths of the first and second segment of the tarsi are sometimes of generic importance (Lachnini), and the comparative lengths of the hind tarsi and the cornicles are oftentimes of specific importance (Aphis, Ptero- comma). A small empodial hair is found between the claws in the Aphidinae. In the Callipterina it is leaf-shaped or spatula-like. In A SYNOPSIS OF THE APHIDIDAE 7 the Aphidina and Lachnina it is hair-like, usually being as long as the claws (except in the Pterocommini, in which it is considerably shorter than the claws). The wings are membraneous and hyaline (except in certain Callipterini, Lachnini, and Macrosiphini), and are held roof-like over the body when. at rest (except Monellia, Phyllox- erinae, Hormaphidina, in which they lie flat on the abdomen). The veins of the fore wings are as follows: the costal and subcostal are almost parallel with the anterior margin; the radial extends from the posterior margin of the stigma to the outer margin of the wing, being either curved or straight ; the discoidals, three in number, extend from the subcostal to the posterior margin of the wing. The outer or third discoidal (media, cubitus of some authors) may be simple (Hormaphidina, Pemphigina), absent (Phylloxerinae), once-branched (Schizoneurina), or twice-branched (Aphidinae, except Toxoptera). On the anterior margin of the fore wing is a dusky spot located be- tween the wing margin and the subcostal veins, and between the distal ends of the costal and subcostal veins, known as the stigma or Pterostigma. It is usually trapezoidal in shape, and does not extend to the tip of the wing (except in Longistigma and Mindarus, in which it reaches well beyond the tip of the wing). The hind wings have one longitudinal and either one or two transverse veins.? In the Pemphiginae and Phylloxerinae dorsal wax glands are sometimes present on the thorax, in which ease their number, shape, and posi- tion are of more or less specific importance. The abdomen consists of nine more or less similar segments. The coloration of the various segments, especially in species in which the color is variegated, is sometimes of specific importance. In certain species wax glands are present on the abdomen (Phylloxerinae, and particularly the stem mothers of Pemphiginae) and may be of use in making determinations. In the Aphidinae the presence or absence and location of small lateral and dorsal tubercles are often important. The anal segment consists of an anal plate and a cauda. The cauda may not be separated from the abdomen (Pemphiginae, Lachnina), or it may be short and conical (Aphidini), short and globular, being constricted in the middle (Callipterina), or it may be long and ensiform or sickle-shaped (Macrosiphini). The anal plate is usually well rounded, being half-moon-shaped, or it may be emarginate or bilobed (Callipterina). On the sixth (or fifth?) segment is a pair 2 For a full discussion of the venation see Patch, Edith M., Homologies of the wing veins of the Aphididae, Psyllidae, Aleurodidae, and Coccidae, Ann. Entom. Soc. Am., vol. 2, pp. 101-136, June, 1909. 8 MISCELLANEOUS STUDIES of short tubular processes, the cornicles (honey tubes, nectaries of some authors). These are quite valuable characters, both specifie and generic. In the Phylloxerinae and most of the Pemphiginae they are lacking, but in the Aphidinae they are always present, and show a great diversity of form. They may be merely pores (certain Callip- terini, Cerosipha cupressi Swain, Lachnus taxifolia Swain), they may be cylindrical, yet quite short (certain Callipterini, Chaitophorini) ; they may be short and cylindrical or conical (Aphidini) ; they may be truncate, cone-shape (Lachnini); they may be clavate and long (certain Callipterina, Pterocommini, Macrosiphini) ; or they may be long and eylindrical (particularly in Macrosiphum and Myzus). BIOLOGY Considerable variety is exhibited in the habits, life history, and methods of reproduction, as well as in the structure and body form. Reproduction is almost entirely parthenogenetic, although certain species at certain times have a sexual reproduction. Fewer species have sexual reproduction in California than in colder climates, due to the fact that mild weather throughout the winter permits them to live over, and hence the eggs are unnecessary. Many species produce generation after generation parthenogenetically, and are most abun- dant in the spring and early summer, but gradually disappear toward midsummer, due partially to their predaceous and parasitic enemies, and partially, undoubtedly, to the heat of the summer. Other species regularly produce sexual forms in the fall, which lay eggs that hatch the next spring. The forms hatching from the eggs are wingless (except in Callipterini) and usually of a different form from the later generations, and are known as the fundatrix or stem mother. The fundatrix is always viviparous. Her progeny consists either of all apterous or partly apterous and partly alate viviparous females (fundatrigenia), which in turn produce other generations of funda- trigeniae. The last asexual generation in the fall, which gives birth to the sexual forms (sexuales), are known as sexupara, and are usually alate. Oftentimes in the second or third and even fourth generation there is a definite migration from one species of host plant to another, where the aphids live over the summer (virgogenia), the sexupara returning to the original species of host in the fall to give birth to the sexuales, which lay their eggs there. Aphis malifoliae Fitch rep- resents an example of this habit, the winter host being apple, the summer plantain. Oftentimes the fall migrants (sexupara) of certain A SYNOPSIS OF THE APHIDIDAE 9 species differ considerably in structure from the spring migrants (fundatrigenia). This is particularly noticeable in the Pemphiginae. Many species are confined throughout the season to one species of host, others to one or two or a few species, while still others may live on any of a number of hosts (Aphis senecio Swain, Rhopalosiphum per- sicae (Sulz.)). All sustenance is derived from the plant juices of the various hosts, but each species is usually confined more or less definately to feeding on some certain part of the plant. Some live entirely upon the leaves, some on the stems of the leaves and small -twigs, some on the trunks and larger branches, some on the roots, some on the flower heads and racemes of the host, and still others feed on almost any part of the plant. The greater number of species are free living, but certain of the Aphidinae form pseudogalls (Aphis pomi De Geer, Aphis malifoliae Fitch, Phyllaphis coweni (Cockerell) ), while the Pemphiginae and Chermisina form true galls. Nearly all of the Pemphigina spend at least part of the season on various species of Populus, the Schizoneurina on Ulmus, while the Lachnini and Chermisina are practically confined to the conifers. The Aphidinae are found mostly on deciduous trees and herbaceous plants, although some live on conifers (Myzaphis abietinus (Walker), Nectarosiphon morrisoni Swain). ECONOMIC CONSIDERATIONS From an economic standpoint most of the species are of no importance, although there are many that are well known pests of ‘cultivated crops. For example the woolly apple aphis (Hriosoma lanigera) 1s a world-wide pest of considerable importance to the apple. The green and the rosy apple aphis (Aphis pomi, A. malifoliae) do a large amount of injury in certain localities, and are extremely difficult to control. The rose aphis (Macrosiphum rosaec) is known the world over, and although living unprotected and easily killed with any of the common contact insecticides, it is recognized by everyone who has grown roses in the dooryard as an extremely troublesome pest. The walnut aphis (Chromaphis juglandicola), the cabbage aphis (Aphis brassicae), the green peach aphis or greenhouse aphis (Rhopalosiphum persicae) are all well known pests. The common contact insecticides are usually efficient for their control. Many species are kept well in check by their predaceous and parasitic enemies, the ladybirds, the syrphid flies, the lacewings, and the braconids. Of the ladybirds, probably the most efficient in California are Coccinella californica 10 MISCELLANEOUS STUDIES Mann., Hippodamia convergens Guerin, and Scymnus nebulosus Le- conte. Of the syrphid flies, those consuming the largest number of aphids and the most abundant in the state* are Catabomba pyrastri Osten-Sacken, Allograpta obliqua Say, Syrphus arcuatus Fallen, S. americanus Wied., S. opinator Will., and Hupeodes volucris Osten- Sacken. Chrysopa californica Coq. and Sympherobius angustus Banks are the most important aphid enemies among the lacewings. Among the Braconidae there are two very common species in California, Lysiphlebus testacetpes Cresson and Diaretus rapae Curtiss. Others have been reared by the author and will be mentioned later. The author wishes to thank Dr. L. O. Howard and Mr. A. B. Gahan of the Bureau of Entomology for their kindness in identifying the various hymenopterous parasites of aphids sent to them. SYNOPSIS Family Aphididae Passerini Passerini, Gli Afidi, 1860. The family Aphididae Passerini is divided into three subfamilies (following Alexander Mordwilko), which are: Aphidinae Buckton, Pemphiginae Mordwilko, and Phylloxerinae Dreyfus. Van der Goot considers but two subfamilies: Aphidinae y. d. G. and Chermisinae v. d. G. His subfamily Aphidinae includes both the Aphidinae and Pemphiginae of Mordwilko, while his Chermisinae is the same as Mordwilko’s Phylloxerinae. Following is a translation of Van der Goot’s descriptions of the two subfamilies : Subfamily Aphidinae y. d. G.: Body very often without distinct groups of glands for the secretion of wax. Antennae usually six- or seven-jointed [when the terminal process of the sixth segment is longer than the segment he considers it as the seventh segment]. Only in a few cases are the apterous forms with three-segmented antennae. The primary sensoria usually have a distinct ‘‘haar- kranz’’ [hairy fringe?]. Cornicles almost always and cauda often present. Fore wings with four veins, the cubitus or media I very often divided: hind wings usually with two cross-veins. Vivi-oviparous: the sexuales mostly of the usual form. Subfamily Chermisinae v.d.G.: Body almost always with distinct groups of glands for the production of wax. Antennae three-segmented, often evidently five- segmented. Sensoria always without ‘‘haarkranz.’’ Cornicles always absent. Fore wings with three veins; hind wings with only one small vein. Always only oviparous: sexuales dwarfish, with or without beak. 3 Davidson, W. M., Syrphidae in California, Jour. Econ. Ent., vol. 9, pp. 454— 457, 1916. A SYNOPSIS OF THE APHIDIDAE 11 The latter subfamily has been considered by the author as Phyllox- erinae Dreyfus; the former as two subfamilies, Aphidinae Buckton and Pemphiginae Mordwilko. Mordwilko gives the following char- acters for these two subfamilies: Subfamily Pemphiginae Mordw.: Antennae of the alate forms five- or six- segmented, the third bearing a specifically definite number of transverse or arch- like sensoria; short, usually not longer than the head and thorax. The apterous parthenogenetic females have four- to six-segmented antennae, but these are sometimes reduced to three or even to two segments. The fore wings of the alate forms have four transverse veins, of which the third or cubital vein [third discoidal] is either simple or once-branched. The hind wings have one or two transverse yeins. The cornicles are either entirely absent or very slightly devel- oped, and in the latter case may not be present in all the forms of one species. Subfamily Aphidinae Buckton: Antennae always six-segmented, except in the stem mother of some species, and in the genus Sipha Passerini. [This genus is not represented in California. In Hssigella Del Guercio, Cerosipha Del Guercio, and Trifidaphis Del Guercio, three Californian genera described since the publi- cation of Mordwilko’s paper, the antennae are but five-segmented.] The last antennal segment often ends in a long thread-like filament which may be longer than the segment. Antennae with a long filament are mostly from half the length of the body to longer than the body. The antennal filament is character- istic only for this subfamily; some genera of the groups Lachnina and Callipterina have a very short filament, and the antennae are not longer than the head and thorax. The sensoria are small and are shaped like dots, circles, or transverse holes, but never archlike or half-rings. Segment 3 bears the largest number, especially in the alate forms. The cubitus [third discoidal] of the fore wings is usually twice-branched although there are some exceptions, as Toxoptera Koch. Most species have long cylindrical cornicles which are often clavate in the middle. Sometimes they may be greatly reduced or poorly developed, and, as in Lachnina and Callipterina, they may be replaced by cupola-shaped elevations. A cauda is usually present, being conicle, ensiform, or globular, although in Lachnina it is not evident. The sexual forms have beaks, and become quite large. Subfamily Aphidinae Buckton Buckton, Mono, British Aphides, 1883. This subfamily is divided into three groups, following Carl Borner (Sorauer, Paul, Handbuch der Pflanzenkrankheiten, vol. 3, p. 664, 1913). Borner considers the family Aphididae as a superfamily, and divides it into four families; so this subfamily Aphidinae he considers a family, and the various groups as subfamilies. Below is a trans- lation of his key: 1. Claws with spatula-like or leaf-shaped empodial hairs (fig. 1). Cornicles vari- ously formed, bare. Pubescence of larvae as in Aphidina. The majority of the species live free and monophagous on trees, only seldom on herbaceous plants, and never migrate collectively -..-...-.------------------+---- Group Callipterina — Claws with simple empodial hairs (fig. 2), often hard to see -.........-..-....-. 2 12 MISCELLANEOUS STUDIES 2. Antennae with short terminal joint (fig. 3), (except in Pterocommini, but then the cauda is not tail-like). Body ridges with more than six longitudinal rows of hairs. Hairy covering mostly thick. Cauda not lengthened tail-like, anal plate widely rounded (fig. 5). Wax glands either present or lacking. Mostly strongly monophagous forms, at times of remarkable size. Found mostly on tree growths and without change of hosts -....... Group Lachnina — Terminal joint of antennae always with a long, slender filamentous projection (fig. 4). Body ridges of young larvae at most with only six longitudinal rows of hairs, which may be increased after the first molt. Cauda either short or lengthened tail-like, anal plate widely rounded (fig. 6). Species monophagous or polyphagous, many with a change of host plants. On PREC Ore herb ACCOUS Ie OT OW GES fa xeesteere cn ee eee teemate eae teen sar neceee eee Group Aphidina Group Callipterina Mord (Subfamily Callipterinae Borner) Mordwilko, Ann. Imperial Acad. Sci., St. Petersb., 1908. Borner, in Sorauer, Handbuch der Pflanzenkrankheiten, vol. 3, p. 664, 1913. According to Borner this group consists of two tribes, the Phyl- laphidini and the Callipterini. He divides the Callipterini into two groups, the Callipterini and the Chaitophori. The author has followed him to a certain extent, but has given each of the last two groups equal rank with the Phyllaphidini, and thus considers this group, Callip- terina, as consisting of three tribes. Below is a key to the same: 1. Wax glands with faceted pore fields present. Antennae as in Lachnina (figs 13))ie ubescence (delicate sssneerceseneceenceseceeeres Tribe Phyllaphidini — Wax glands lacking or without faceted pore fields. Pubescence often very remarkable. Terminal joint of the antennae often lengthened into a bristle (ESS 0) aera eee 2 2. Anal plate more or less emarginate or bilobed (fig. 7), except in Euceraphis TER een cn te Tribe Callipterini — Anal plate widely truncate or rounded (fig. 8) --............ Tribe Chaitophorini Tribe Phillaphidini Borner Borner, in Sorauer, Handbuch der Pflanzenkrankheiten, vol. 3, p. 664, 1913. This tribe Phyllaphidini consists of but one genus, Phyllaphis Koch, which is represented in California by three species. 1. Genus Phyllaphis Koch Koch, Die Pflanzenlause, p. 248, 1857. Type Aphis fagi Linn. Key To CALIFORNIA SPECIES 1, Alate viviparous females unknown. Wing venation of alate males similar to that of Eriosoma spp. (fig. 17). Forming pseudogalls on edges of leaves or living free in masses of white flocculence on leaves of Quercus spp. quercicola Baker A SYNOPSIS OF THE APHIDIDAE 13 — Alate ¥iviparous females common. Venation normal, the third discoidal being twice-branched. Not On Quercus SPP. -eq.--c-2:<-----c-n