SEMICENTENNIAL PUBLICATIONS OF THE UNIVERSITY OF CALIFORNIA 1868-1918 MISCELLANEOUS STUDIES IN AGRICULTURE AND BIOLOGY UNIVERSITY OF CALIFORNIA PRESS BERKELEY 1919 Q in CONTENTS PAGES A Synopsis of the Aphididae of California, by Albert F. Swain 1-221 Mutation in Matthiola, by Howard B. Frost 223-333 Ocean Temperatures, their Relation to Solar Radiation and Oceanic Circulation, 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 . .. 423-450 A SYNOPSIS OF THE APHIDIDAE OF CALIFORNIA BY ALBERT F. SWAIN [University of California Publications in Entomology, Vol. 3, No. 1, pp. 1-221, pis. 1-17] A SYNOPSIS OF THE APHIDIDAE OF CALIFORNIA BY ALBERT F. SWAIN CONTENTS PAGE Introduction 2 Classification 4 External anatomy 5 Biology 8 Economic considerations 9 Synopsis 10 Family Aphididae 10 Subfamily Aphidinae 11 Group Callipterina 12 Tribe Phyllaphidini 12 Tribe Callipterini 16 Tribe Chaitophorini 32 Group Lachnina 39 Tribe Pterocommini 39 Tribe Lachnini 43 Group Aphidina 52 Tribe Macrosiphini 52 Tribe Aphidini 87 Subfamily Pemphiginae 138 Group Hormaphidina _ 139 Group Pemphigina 140 Group Schizoneurina 147 Group Vacunina 150 Subfamily Phylloxerinae 151 Group Chermisina 151 Group Phylloxerina „ 152 2 MISCELLANEOUS STUDIES PAGE Appendix 1. Keys to the genera and tribes of Aphididae; a translation from P. Van der Goot _ 154 Appendix 2. Host plant list _ 159 Addenda - — . 178 Explanation of plates _ 180 Index to genera and species 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. 0. Essig and W. M. Davidson published the results of their earlier studies. Since then both have added papers occasionally. 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 occur in California. This number will undoubtedly be greatly increased 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; Jo E. 0. 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 manuscript; 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 thf 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 redescribed 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 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 scale 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 body1 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 circular. 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, E. A., A comparative study of the external anatomy of plant lice, 12th Eept. 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 circular, 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-jointed 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.2 In the Pemphiginae and Phylloxerinae dorsal wax glands are sometimes present on the thorax, in which case 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. Soe. 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 specific 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 cylindrical (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 fundatfix 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 malifoliue 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 TJlmus, 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 dbietinus (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 (Eriosoma lanigera) is 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 rosae) 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 (Chroniaphis 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 californ-ica 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 state3 are Catabomba pyrastrl Osten-Sacken, Allograpta obliqua Say, Syrphus arcuatus Fallen, 8. americanus Wied., 8. opinator Will., and Eupeodes volucris Osten- Sacken. Chrysopa, calif omica 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 testaceipes Cresson and Diaretus rapae Curtiss. Others have been reared by the author and will be mentioned later. The author wishes to thank Dr. L. 0. 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 v. 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 v. 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. Pore wings with three veins; hind wings with only one small vein. Always only oviparous: sexuales dwarfish, with or without beak. s 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 veins. 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 Essigella 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 tree or herbaceous growths Group Aphldina 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 (fig. 13). Pubescence delicate Tribe Phyllaphidini — Wax glands lacking or without faceted pore fields. Pubescence often very remarkable. Terminal joint of the antennae often lengthened into a bristle (fig. 30) 2 2. Anal plate more or less emarginate or bilobed (fig. 7), except in Euceraphis Koch 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. L Genus Phyllaphis Koch Koch, Die Pflanzenlause, p. 248, 1857. Type Aphis fagl 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 viviparous females common. Venation normal, the third discoidal being twice-branched. Not on Quercus spp 2 2. Antennae short, stout, with oval transverse sensoria (fig. 13). Forming galls on Arctostaphylos spp. (and Arbutus spp.) _ coweni (Ckll.) — Antennae longer and narrower with circular sensoria (figs. 9, 14-17). Living under thick masses of white flocculence on Fagus spp fagl (Linn.) 1. Phyllaphis coweni (Ckll.) Figure 13 Cockerell, Can. Ent., vol. 37, pp. 391-392. 1905. Pemphigus (orig. desc.). Davidson, Jour. Econ. Ent., vol. 4, pp. 559, 1911. Cryptosiphum tahoense n.sp. (desc.). Davidson, Jour. Econ. Ent., vol. 5, p. 404, 1912 (list). Essig, Pom. Jour. Ent. Zool., vol. 7, pp. 187-195, 1915 (desc.). Records. — Arctostaphylos manzanita; Oakville, Napa County, February, 1913 (E. L. Brannigan) ; Mount Diablo, Contra Costa County (Davidson) ; Jasper Eidge, Santa Clara County, October, 1914 (E. A. Cornwell) ; Pine Hills, San Diego County, June, 1916.* A. pumella, A. tomentosa, Lake Tahoe, August, 1911 (Davidson) : A. glauca, Alpine, San Diego County, June, 1916. This species is found more or less abundantly throughout the state wherever its host plants occur. Essig (1915) states it is found throughout the Rocky, Sierra Nevada, and Coast Range mountains, being more abundant in the central and northern parts of the state. The author has found it to be extremely abundant in the Cuyamaca and Laguna mountains in the extreme southern part of the state. The insects can be found at any time of the year in the galls on manzanita although most abundantly in the early fall. Collections by the author in June showed that the stem mothers and young vir- gogeniae only were present. A few weeks later the alate females were abundant, while in August the sexual es begin to appear. However, the alate viviparous females have been found in October and in February. This species forms galls on the leaves, and flower and fruit stalks of its host. Usually there is but one gall to a leaf, although sometimes four or five may be found. When first formed these galls are concolorous with the leaves; but as they become older they turn more and more reddish in color, until when mature they are a very bright red. 2. Phyllaphis fagi (Linn.) Figures 9 to 12 Linnaeus, Syst. Nat., vol. 2, p. 735, 1735. Aphis (orig. desc.). Davidson, Jour. Econ. Ent., vol. 3, p. 376, 1910 (list). Eecords. — Fagus sp., Palo Alto, 1910 (Davidson) ; Fagus sylvatica, Stanford University, April to May, 1915. * Records in which no collector 's name is mentioned refer to collections made by the author. 14 MISCELLANEOUS STUDIES This species has been taken only in the vicinity of Stanford Uni- versity, where it infests copper beach (Fagus sylvatica). It may be easily recognized by the masses of whitish flocculence on the under side of the leaves. Each mass contains one individual, which is entirely hidden by it. In looking up the literature of this species the author found that there has been no description of it published in America, so below is included a brief description of specimens taken near Stanford University on April 28 and May 29, 1915. Alate viviparous female. — Prevailing color dark green, covered .with a whitish flocculence. This flocculence consists of wax threads as much as 3 mm. long. Head dusky, with frontal margin black. Eyes red. Antennae dusky, except II and basal one-third of III, which are pale. Beak pale with apex and joints dusky. Thorax dusky green with lobes black. Abdomen dark green with a row of black spots on each margin and about seven black transverse dorsal bands. Cornicles black. Cauda and anal plate concolorous with abdomen with distal margins slightly darker. First and second femora pale with apices only dusky; third femora dusky throughout. First tibiae pale with apex dusky; second and third dusky throughout. Tarsi black. Wings hyaline, stigma gray. Head twice as wide as long, furnished with many small wax glands. Antennae reaching to the cornicles or to the base of the cauda, set on small tubercles (fig. 12). Ill is the longest segment, followed by IV, V, and VI. VI spur is merely a thumb-like projec- tion (fig. 16). The usual primary and accessory sensoria are present on V and VI. Secondary sensoria are found only on III (fig. 9). These are fairly large, almost circular, and placed in a single row along the segment. They number from four to seven, five being the average. The beak is short, reaching but slightly beyond the first coxae. The wings are normal, with a twice-branched third discoidal. The cornicles are merely small pores. The cauda is short and knobbed, the anal plate emarginate or bilobed (fig. 11). Measurements : Body length 2.0 to 2.4 mm., width 0.8 to 1.04 mm., antennae total 1.55 to 2.06 mm., Ill 0.591 to 0.77 mm., IV 0.34 to 0.47 mm., V 0.27 to 0.39 mm., VI 0.19 to 0.25 mm., cornicles (diameter) 0.05 mm. Apterous viviparous female. — Prevailing color under flocculence pale yellowish green. Light brown markings as follows: two rows of four spots each across the prothorax, one large spot on each margin and one on the dorsum of the thorax, four spots on each abdominal A SYNOPSIS OF THE APHIDIDAE 15 segment, two dorsal and two marginal. Antennae pale except VI, apical two-thirds of V, and apical one-third of IV. Legs pale with light brown spots at joints; tarsi black. Cauda small and conicle, cornicles not evident. Measurements : Body length 2.9 to 3.0 mm., width 0.96 to 1.2 mm., antennae total 1.26 mm., Ill 0.36 mm., IV 0.32 mm., V 0.204 mm., VI 0.205 mm. 3. Phyllaphis quercicola Baker Figures 14 to 20 Clarke, Can. Ent., vol. 35, p. 248, 1903. Schizoneura querci (Fitch) (list). Davidson, Jour. Econ. Ent., vol. 3, p. 374, 1910. S. querci (Fitch) (list). Davidson, Pom. Jour. Ent., vol. 3, p. 398, 1911. S. querci (Fitch) (list). Davis, Ent. News, vol. 22, p. 241, 1911. Phyllaphis querci (Fitch) (biblig.) Davidson, Jour. Econ. Ent., vol. 7, p. 127, 1914. P. querci (Fitch) (note). Gillette, Ent. News, vol. 25, p. 274, 1914. Phyllaphis sp. (list). Baker, Ent. News, vol. 27, p. 362, 1916. P. quercicola n.n. for P. querci (Fitch) of Davis. Eecords. — Quercus agrifolia; Placer, Contra Costa, Santa Clara counties (Davidson, Clarke); Stanford University, April, 1915; Berkeley, September, 1915; Wynola, San Diego County, June, 1916; Charter Oak, Los Angeles County, Novem- ber, 1916. Quercus lobata, Stanford University (Davidson) ; Q. wislizenii, Placer County (Davidson); Q. dumosa, San Diego, August, 1915; Quercus sp., Spreckels, Monterey County, 1913 (Gillette). This is a very common species of woolly aphis on the oaks, par- ticularly the live oak, through southern and central California. According to Davidson (1914) the stem mothers occur in pseudogalls on the edges of the leaves. The second generation lice, when mature, leave these galls to live on the upper and lower surfaces of the leaves, unprotected except for their -woolly covering. The sexes, apterous oviparous females and alate males, occur late in the fall. The vivi- parous generations are all apterous. The writer has observed the stem mothers as late as August in San Diego County, while he has found the viviparous females on the under side of the leaves as early as mid-June in Berkeley. The identity of this species has never been definitely established. It was thought to be the species described by Fitch (Kept. Ins. N. Y., vol. 5, p. 804, 1859) as Eriosoma querci, but in 1916 Baker pointed out the identity of Eriosama querci Fitch, proving it to be identical with a species of Anoecia found on Cornus and formerly considered to be A. corni Fab. Baker's decision is that the Quercus-Cornus species of the eastern United States is Anoecia querci (Fitch) and 16 MISCELLANEOUS STUDIES is distinct from our western one. In 1911 Davis described a species of woolly aphis from oak under the name of Phyllaphis querci (Fitch) stating that it is the same one as listed by Davidson. Baker proposes the name Phyllaphis quercicola for this species described by Davis. Consequently it is so listed in this paper. This species is not a typical Phyllaphis, but it fits that genus better than any other so is placed there provisionally. The figures (14—20) are from a specimen of alate male in the Davidson collection in Stanford University. Tribe Callipterini Wilson Wilson, Can. Ent., vol. 42, p. 253, 1910. The genera included in this tribe differ somewhat as considered by various entomologists. Since Wilson has worked out the synonomy of the various genera very well he is followed in preference to some of the European authors, although there are some points in which he is mistaken. For instance, he places Pterocalli-s Passerini, Callip- teroides Mordwilko, Tuberculatus Mordwilko, Subcallipterus Mord- wilko, and Therioaphis Walker as synonyms of Myzooallis Passerini. In regard to this, he states, "In 1894 Mordwilko used A. coryli Goetze as the type of his genus Callipteroides, but as this species ..." He is mistaken in this, for in the paper referred to, Mordwilko used A. coryli Goetze as the type of the genus Myzocallis Passerini, and in 1908 he gave as the type of Callipteroides, Callipterus nigritarsus Heyden (betulae Koch). If nigritarsus Hey den is a synonym of betulae Koch, as Mordwilko indicates, then Callipteroides is a synonym of Enceraphis Walker, for C. betulae Koch certainly falls into this genus, as described by Wilson himself. The key to the California genera below is adapted from Wilson's key (Can. Ent., vol. 42, pp. 253-254, 1910). KEY TO CALIFORNIA GENERA OF CALLIPTERINI 1. Antennal tubercles prominent (fig. 21); antennae always exceedingly long.... 2 — Antennal tubercles wanting or very small (fig. 22) ; antennae variable, some- times shorter than the body 3 2. Cornicles very long and large (figs. 23-24) 4 — Cornicles very short and more or less constricted in the middle 5 — Cornicles little more than pores (fig. 25). Wings held horizontal at rest. Monellia Oestlund 3. Cornicles distinct, usually being longer than broad in the middle (fig. 26) 6 — Cornicles little more than pores, and broader than long (fig. 25). Wings held horizontal at rest ... ....Monellia Oestlund A SYNOPSIS OF THE APHIDIDAE 17 4. Cornicles one-fourth the length of the body or more, swollen in the middle (fig. 24) Drepanosiphum Koch — Cornicles large and nearly one-fourth the length of the body, swollen at the base and tapering toward the middle (fig. 23) ....Drepanaphis Del Guercio 5. Inner side of antennal tubercles about one-half the length of the inner side of the first antennal joint (fig. 29) Euceraphis Walker — Inner side of antennal tubercles more than one-half the length of the inner side of the first antennal segment (figs. 27-28) Calaphis Walsh 6. Antennae longer than body, except in Callipterinella, with VI spur not much shorter than VI base (fig. 31) 7 — Antennae shorter than the body, with VI spur very short, often being little more than a nail-like process (fig. 34) 9 7. VI spur considerably longer than VI base, being one and one-half to two times as long. Anal plate emarginate but not deeply bilobed. Callipterinella Van der Goot — VI spur about equal to or shorter than VI base. Anal plate deeply bilobed 8 8. VI spur and VI base subequal (fig. 31). Cornicles twice as long as broad in the middle and constricted in the middle (figs. 26, 32). Myzocallis Passerini — VI spur shorter than VI base (fig. 30). Cornicles much broadened at base (fig. 33) Eucallipterus Schouteden 9. VI spur less than one-half the length of VI base (fig. 34). Cornicles not longer than broad at the base, and constricted in the middle (fig. 35). Chromaphis Walker — VI spur at least one-half as long at VI base (figs. 63, 66). Cornicles short, about as long as broad and placed on a broad base Callipterus Koch 2. Genus Drepanosiphum Koch Koch, Die Pflanzenlause, p. 201, 1855. Type Aphis palantanoides Schrank. 4. Drepanosiphum platanoides (Schrank) Figures 21, 24, 36 Schrank, Fauna Boic., vol. 2, p. 1206, 1801. Aphis (orig. desc.). Wilson, Jour. Econ. Ent., vol. 2, p. 349, 1909 (desc. ala. vivi., ala. ovi. females). Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1910 (list). Essig, Pom. Jour. Ent., vol. 4, p. 759, 1912 (list). Records. — Acer macrophyllum, A. negundo; Berkeley, 1915 (Essig) ; Stan- ford University, October, 1914, April, 1915; A. pseudoplatanus, Stanford Univer- sity, November, 1914 (Morrison); A. saccharum, Berkeley, June, 1915; Platamis racemosus, Stanford University (Davidson) ; Acer sp., San Lorenzo, 1908 (Wil- son). This is a very common species in the San Francisco Bay region on various species of maples, and on box elder and western sycamore. In April the alate and apterous viviparous females are abundant, remaining so throughout the summer and early fall. In the later fall (October and November) the sexes appear. Just where the eggs 18 MISCELLANEOUS STUDIES are laid the author is unable to say. A curious fact is that thp oviparous females are alate as well as apterous. The author has never seen the alate forms, but Wilson (1908) describes them. 3. Genus Drepanaphis Del Guercio Del Guercio, Eivista di patologia vegetable, vol. 4, pp. 49-53, 1909. Type Siphonophora acerifolii Thomas. 5. Drepanaphis acerifolii (Thomas) Figures 23, 37 Thomas, Illinois Lab. Nat. Hist., Bull. 2, p. 4, 1878. Siphonophora (orig. desc. ) . Clarke, Can. Ent., vol. 35, p. 249, 1903. Drepanosiphum (list). Sanborn, Kan. Univ. Sci., Bull. 3, p. 45, 1904. Drepanosiphum (desc. ala.). Davidson, Jour. Econ. Ent., vol. 2, p. 303, 1909. Drepanosiphum (list). Davidson, Jour. Econ. Ent., vol. 3, p. 380, 1910. Macrosiphum (list). Essig, Pom. Jour. Ent., vol. 4, p. 760, 1912 (list). Essig, Mon. Bull., Cal. Comm. Hort., vol. 3, p. 85, 1914 (list). Essig, Mon. Bull., Cal. Comm. Hort., vol. 3, p. 445, 1914 (list). Records. — Acer sp. : Stanford University (Davidson); Sacramento (Essig); Hanford, Fresno County (B. V. Sharp) ; A. macrophyllum, A. saccharinum, Berke- ley, July to October, 1915; Riverside, October, 1916; A. dasycarpum, A. plat- anoides, Berkeley, 1915 (Essig); Quercus sp. (live oak), Berkeley (Clarke) (f). This is as common a species on maple in the San Francisco Bay region as the preceding one. It has also been taken in the Sacramento and the San Joaquin valleys, and in southern California. It is a species easily recognized by its dark markings and the dorsal tubercles on the first and second abdominal segments. 4. Genus Calaphis Walsh Figure 28 Walsh, Proc. Ent. Soc. Phila., vol. 1, p. 301, 1863. Type C. betulella n.sp. 6. Calaphis betulaecolens (Fitch) Figures 27-38 Fitch, Cat. Homop. N. Y., p. 66, 1851. Aphis (orig. desc.). Clarke, Can. Ent., vol. 35, p. 249, 1903. Callipterus (list). Davidson, Jour. Econ. Ent., vol. 2, p. 301, 1909. Callipterus (list). Davidson, Jour. Econ. Ent., vol. 3, p. 376, 1910. Callipterus (list). Essig, Pom. Jour. Ent., vol. 3, p. 556, 1911 (syn.). Davidson, Jour. Econ. Ent., vol. 5, p. 404, 1912 (desc. sexes). Essig, Pom. Jour. Ent., vol. 4, p. 760, 1912 (list). Essig, Mon. Bull., Cal. Comm. Hort., vol. 3, p. 445, 1914 (list). Baker, Proc. Ent. Soc., Washington, vol. 18, p. 186, 1916 (desc.). Records. — Betula, sp., Alameda, Contra Costa, Santa Clara counties (Clarke, Davidson, Essig, Morrison, and the author). A SYNOPSIS OF THE APHIDIDAE 19 This is a common species of aphid on birch (Betula spp.) in the San Francisco Bay region. In the early part of March the eggs begin to hatch. In 1915 at Stanford University eggs began to hatch on March 8, the process continuing for several days. A month later both alate and apterous females were quite abundant; the alate females being undoubtedly the stem mothers, the apterae belonging to the second generation. Viviparous generations appeared through- out the summer. During August the sexes, alate males and apterous oviparous females, occurred. In 1914 the sexes and sexupara were noticed on August 28. Egg laying occurred shortly afterward, the eggs being laid in the crotches of the twigs and under the curled edges of the bark. Birch is the only recorded host plant. 5. Genus Euceraphis Walker Walker, The Zoologist, p. 2001, 1870. Type Aphis letulae Koch. KEY TO CALIFORNIA SPECIES 1. Body light green; third joint of antennae with about 13-18 sensoria on basal one-half (fig. 39) giUettei Dvdn. — Body yellow with dark markings on head and thorax, and often with as many as eight black transverse stripes on the abdomen (the number varies between none and eight) ; third antennal segment with 19-25 sensoria (fig. 40) betulae (Koch) 7. Euceraphis betulae (Koch) Figures 29, 40 Koch, Die Pflanzenlause, p. 217, 1855. Callipterus (orig. dese.). Davidson, Jour. Econ. Ent., vol. 5, p. 405, 1913 (desc. ovi. female). Davidson, Jour. Econ. Ent., vol. 7, p. 129, 1914 (desc. stem mother). Records. — Betula sp. : Oakland (Davidson); Palo Alto, March to April, 1915. Davidson lists this species, describing the stem mother and oviparous female from the San Francisco Bay region. The author found it in Palo Alto during March and April, 1915, on Betula alba. According to Davidson the stem mothers hatch from the eggs about the middle of February, feeding on the stems until the leaves open in March. The viviparous generations occur during the summer. He took the oviparous females in November. His description of the stem mother gives three dusky transverse bands on the abdomen. The author has found this to be variable, the number ranging from none to eight. 20 MISCELLANEOUS STUDIES 8. Euceraphis gillettei Davidson Figure 39 Clarke, Can. Ent., vol. 35, p. 248, 1903. Lachnus alnifoliae Fitch (list). Davidson, Jour. Econ. Ent, vol. 2, p. 300, 1909. L. alnifoliae Fitch (list). Davidson, Jour. Econ. Ent., vol. 3, p. 375, 1910. L. alnifoliae Fitch (list). Essig, Pom. Jour. Ent., vol. 4, p. 773, 1912. Lachnus alnifoliae Fitch (list). Essig, Pom. Jour. Ent., vol. 4, p. 773, 1912. Lahnus alnifoliae Fitch (note). Davidson, Jour. Econ. Ent., vol. 8, p. 421, 1915 (orig. dese.). Records. — Alnus rhombifolia; Berkeley (Clarke), Stanford University, San Jose, Walnut Creek (Davidson), Stanford University, March, 1915. This species was reported from alder by Clarke and Davidson as Lachnus alnifoliae Fitch. Essig, in his Host plant list of California Aphididae, lists Callipterus alnifoliae (Fitch) on Alnus rhombifolia, but later states that this citation should be Lachnus alnifoliae Fitch. Therefore he referred to this new species of Davidson. The author took both apterous and alate viviparous females of this species on Alnus rhombifolia, along the banks of the San Francisquito Creek, near Stanford University, on March 19, 1915. During the spring it was quite common there. 6. Genus Eucallipterus Schouteden Schouteden, Mem. Soc. Ent. Belg., vol. 12, 1906. Type Aphis tiliae Linn. KEY TO CALIFORNIA SPECIES 1. Wings hyaline; III pale except at the apex, with 5-7 sensoria on the basal one-fifth (fig. 41) flava (Dvdn.) 2. Wings with veins clouded; III with apical one-fifth and basal one-half dusky, and with about 13-15 sensoria on the basal one-half (fig. 42). tiliae (Linn.) 9. Eucallipterus flava (Davidson) Figure 41 Davidson, Jour. Econ. Ent., vol. 5, p. 406, 1912. Euceraphis (orig. desc.). Davidson, Jour. Econ. Ent., vol. 8, p. 423, 1915 (desc. sexes). Records. — Alnus rhombifolia; San Jose, Walnut Creek (Davidson), Stanford University (Morrison). This is an uncommon species in the San Francisco Bay region on Alnus rhombifoli-a, occurring on the under side of the leaves. The author has never collected it, but has specimens from Davidson, taken A SYNOPSIS OF THE APHIDIDAE 21 in April, 1913, near Walnut Creek, Contra Costa County. According to Davidson the sexes appear in October, egg laying occurring during the first part of November. The eggs are laid at the axils of the new buds and on the twigs or canes. These hatch the following spring, the stem mothers being found in the early part of April. 10. Eucallipterus tiliae (Linn.) Figures 7, 30, 33, 42, 50 Linnaeus, Syst. Nat., vol. 2, p. 734, 1735. Aphis (orig. dese.). Davis, Ann. Ent. Soc. Amer., vol. 2, p. 33, 1909. Callipterus (desc., biblio.). Davidson, Jour. Econ. Ent., vol. 2, p. 302, 1909. Callipterus (list). Davidson, Jour. Econ. Ent., vol. 3, p. 372, 1910. Callipterus (list). Davidson, Jour. Econ. Ent., vol. 3, p. 376, 1910. Callipterus (list). Essig, Pom. Jour. Ent., vol. 4, p. 763, 1912 (list). Records. — Tilia americana, Tilia curopea; Stanford University (Davidson), Berkeley, August, 1914 (Essig) ; Stanford University, April to May, 1915; Berke- ley, June, 1915. In the Sari Francisco Bay region this very pretty aphid is quite common on basswood or linden. The author has taken it throughout April, May, and June. Essig found it abundantly in August. It is very easily recognized when found at rest on the under side of the leaves of its host by the two black lines extending from the front o£ the head along the margins of the thorax and joining with the costal margins of the wings. It so appears that these lines are continuous from the front to the tip of the wings. 7. Genus Myzocallis Passerini Passerini, Gli Afidi, p. 28, 1860. Type Aphis coryli Goetze. KEY TO CALIFORNIA SPECIES 1. Wings hyaline 6 — Wings not hyaline, with portions shaded (fig. 262) .. 2 2. Costal cell of wings hyaline (figs. 266, 267) 3 — Costal cell of forewings dusky or shaded (figs. 263, 264) 5 3. First discoidal vein dusky, otherwise the wing is hyaline. VI with spur shorter than base. Apical one-half of III dusky (fig. 47). Cornicles pale. Found on Alnus spp alnifoliae (Fitch) — Wings not as above (figs. 266, 267). VI with spur either equal to or longer than base. Ill with less than apical one-half dusky 4 4. Cornicles pale. Abdomen without dusky dorsal markings. On Quercus spp. maurerl Swain — Cornicles dusky (fig. 62). Abdomen with dusky dorsal markings. On Casta- nea spp. and Quercus spp davidsoni Swain 22 MISCELLANEOUS STUDIES 5. Cornicles pale. Wings with greater portion cloudy (fig. 262). Antennae with only tips of III to VI dusky. On Quercus spp discolor (Monell) — Cornicles pale with apex dusky. Wings with dusky band along costal margin (fig. 263). Antennae with tips of III and IV, apical one-half of V, and all of VI and spur dusky. On Quercus spp bellus (Walsh) 6. Abdomen with four spine-like tubercles on the dorsum of the first segment. VI with base and spur subequal, III being considerably longer than both. Cornicles pale, small, and inconspicuous. On Ulmus spp. ulmifolii (Monell) -•— Abdomen without tubercles as above 7 7. Ill shorter than VI (base and spur). On Quercus spp punctatus (Monell) — Ill not shorter than VI (base and spur) 8 8. VI with spur about twice as long as base (fig. 44). Cornicles pale. On Corylus spp coryli (Goetze) — VI with spur at most only slightly longer than base 9 9. Ill with apex only dusky (figs. 57, 58). Cauda pale 10 - Ill dusky throughout (fig. 268) or with apex and a band near the base dusky (fig. 48). Cauda dusky 11 10. Cornicles pale. Antennae longer than body. Sensoria on III (two or three in number) small and located close to the base of the segment (fig. 57), On Pasania spp pasaniae Dvdn. — Cornicles dusky, at least apical one-half. Antennae not longer than the body. Sensoria on III (five or more in number) fairly large and on basal two- thirds of segment (fig. 58). On Quercus spp quercus (Kalt.) 11. Abdomen with dusky dorsal markings. Ill dusky throughout (fig. 268). On Arundo spp arundinariae Essig — Abdomen without dusky dorsal markings. Ill with apex and band near base dusky (fig. 48). On Arundo spp arundicolens (Clarke) 11. Myzocallis alnjfoliae (Fitch) Figure 47 Fitch, Cat. Homop. N. Y., p. 67, 1851. Lachnus (orig. desc.). Essig, Pom. Jour. Ent., vol. 4, p. 764 (762), 1912. M. alni (Fabr.) (desc. viviparae). Baker, Jour. Econ. Ent., vol. 10, p. 421, 1917 (note). Records. — Alnus rhombifolia; Santa Paula (Essig). Only once has this species been taken in California, by Essig in August, 1911, near Santa Paula, Ventura County. At that time it was very abundant on the under side of the leaves, causing a large amount of sooty mold. 32. Myzocallis arundicolens (Clarke) Figures 22, 48, 51, 52 Clarke, Can. Ent., vol. 35, p. 249, 1903. Callipterus (orig. desc.). Davidson, Jour. Econ. Ent., vol. 2, p. 301, 1909. Callipterus (list). Davidson, Jour. Econ. Ent., vol. 3, p. 376, 1910. Callipterus (list). Essig, Pom. Jour. Ent., vol. 4, p. 762, 1912 (list, in part). Essig, Univ. Calif. Publ. Entom., vol. 1, p. 305, 1917 (desc.). H A SYNOPSIS OF THE APHIDIDAE 23 Records. — Bamboo, Berkeley (Clarke, Essig) ; Arundinaria japonica, Berkeley, June, 1915. In the San Francisco Bay region and in the Sacramento Valley this species is often found infesting the upper and lower surfaces of the leaves of various bamboos, particularly species of Arundinaria, Bambusa, and Phyllostachys, and the giant reed (Arundo donax). Reports list it from Alameda, Sacramento, San Francisco, and Santa Clara counties. The species described by Davidson (1914) as Eucal- lipterus arundicolens (Clarke) and reported from southern California by Essig (1912) proves to be distinct, and was described by Essig (1917) as M. arundinariae. The following brief description is from a collection made by the author on June 9, 1915, from Arundinarm japonica on the campus of the University of California in Berkeley. Alate viviparous female. — (Second generation?) Prevailing color, pale yellow. Head twice as wide as long, pale yellow, with prominent red eyes. Antennal tubercles absent. Antennae longer than body ; formula III, IV, V, VI spur, VI base, I, II. Segments all pale except the margins of I and II, the apices of III, IV, V, and a band about one-sixth the length of III a short distance from the base of III (fig. 48), which are black, and VI which is slightly dusky. There are five or six transverse secondary sensoria on III, located in the dark band. The usual primary sensoria are present on V and VI, and the usual accessor sensoria on VI. Beak pale and short, reaching only to the middle of the first coxae. Thorax and abdomen normal, pale yellow, without tubercles or dusky markings. Cornicles (fig. 51) pale, short, broader at base than at apex. Cauda short, constricted in the middle, with distal end black. Anal plate (fig. 52) pale, deeply bilobed. Wings normal, hyaline, with the first and second discoidal veins and the base of the stigmal vein darker than the others. There is a perceptible shading at the tip of each vein. Measurements: Body length 1.326 to 2.023 mm. (av. 1.644 mm.), width of thorax 0.51 to 0.68 mm. (av. 0.612 mm.), antennae total 2.839 to 3.077 mm. (av. 2.9299 mm.), Ill 0.8925 to 0.986 mm. (av. 0.9324 mm.), IV 0.578 to 0.663 mm. (av. 0.6423 mm.), V 0.527 to 0.561 mm. (av. 0.5403 mm.), VI base 0.306 to 0.323 mm. (av. 0.3103 mm.), VI spur 0.34 to 0.425 mm. (av. 0.3691 mm.), cornicle 0.595 to 0.765 mm. (av. 0.7002 mm.), cauda 0.153 mm., wing length 2.25 to 3.96 mm. (av. 2.9097 mm.), width 1.02 to 1.122 mm. (av. 1.071 mm.), expansion 6.341 to 6.97 mm. (av. 6.6555 mm.). 24 MISCELLANEOUS STUDIES 13. Myzocallis arundinariae Essig Figure 268 Essig, Pom. Jour. Ent., vol. 4, p. 762, 1912. M. arundicolens (Clarke) (in part). Davidson, Jour. Econ. Ent., vol. 7, p. 129, 1914. Eucallipterus arundi- colens (Clarke) (desc. viviparae). Essig, Univ. Calif. Publ. Entom., vol. 1, pp. 302-305, 1917 (orig. desc.). Becords. — Arundo sp., San Francisco Bay region (Davidson) ; Arundinaria japonica, Santa Barbara (Essig); Riverside, January to May, 1917; Arundo donax, San Diego, April to June, 1916. This is the commonest bamboo-infesting species in southern Cali- fornia and parts of central California. For some time it was con- sidered as M. arundicolens (Clarke) but this past year Essig pointed out the differences, describing it as a new species. 14. Myzocallis bellus (Walsh) Figures 45, 46 Walsh, Proc. Ent. Soc. Phila., vol. 1, p. 299, 1862. Aphis (orig. desc.). Essig, Pom. Jour. Ent. Zool., vol. 7, pp. 195-200, 1915. Callipterus (desc.). Eecords. — Quercus agrifolia, Alhambra, Los Angeles County (Essig) ; Ventura (Essig). Two collections have been made of this species in California, both in southern California, in January, 1912, in Alhambra, and in May, 1913, in Ventura. Both of these consisted only of the alate females (stem mothers), and were described by Essig. 15. Myzocallis davidsoni Swain Figures 60, 61, 62, 267 Clarke, Can. Ent., vol. 35, p. 249, 1903. Callipterus castaneae Fitch (list). Davidson, Jour. Econ. Ent., vol. 3, p. 376, 1910. Callipterus castaneae (Buckton) (list). Davidson, Jour. Econ. Ent., vol. 5, p. 405, 1912. Calapliis castaneae (Buck- ton) (desc. sexuales). Essig, Pom. Jour. Ent., vol. 4, p. 760, 1912. Calaphis castaneae (Fitch) (list). Swain, Trans. Am. Ent. Soc., vol. 44, p. 1, 1918 (orig. desc.). Eecords. — Castanea sp., Berkeley (Clarke, Essig, Swain), Stanford University (Davidson, Swain), San Jose (Davidson); Quercus pedunculata, Berkeley (Swain, Essig). This species was first reported in California by Clarke as Callip- terus castaneae Fitch and later by Davidson as Cattipterus castaneae A SYNOPSIS OF THE APHIDIDAE 25 Buckton. Recently the author described the species from specimens taken in Berkeley on chestnut and oak. It cannot be the Callipterus castaneae of Fitch, because the latter is really a Calaphis. It may be the same species that Buckton had when describing his Callipterus castaneae, in which case his name would be dropped as Fitch's species has priority, and is replaced by the author's name, M. davidsoni. It is more or less common throughout the San Francisco Bay region on chestnuts, and in one case on two specimens of Quercus pedunculata in Berkeley. The stem mothers appear during the late spring, in April and May. Viviparous generations are produced throughout the summer, the sexuales occurring in October and November. ]6. Myzocallis coryli (Goetze) Figures 43, 44, 53, 54 Goetze, Ent. Beitrage, vol. 2, p. 311, 1778. Aphis (orig desc.). Clarke, Can. Ent., vol. 35, p. 249, 1903. Callipterus (list). Davis, Jour. Econ. Ent., vol. 3, p. 417, 1910. Callipterus (desc.). Essig, Pom. Jour. Ent., vol. 4, p. 762, 1912 (list). Records. — Corylus sp., Berkeley (Clarke) ; Corylus rostrata, San Francisco Bay region (Davidson) ; C. rostrata var. calif ornica, C. maxima, Berkeley, August, 1914, June to July, 1915. In the San Francisco Bay region this species is quite common on alder. During the seasons of 1914 and 1915 the author observed it to be very abundant on species of alder on the University of California campus. He has never found it in the south, however. 17. Myzocallis discolor (Monell) Figures 262, 263 Monell, U. S. Geol. Geog. Surv., Bull. 5, p. 30, 1879. Callipterus (orig. desc.). Williams, Univ. Neb. Studies, vol. 10, p. 115, 1910. Callipterus (desc.). Record. — Quercus macrocarpa, Sacramento, October, 1916 (Davidson). The author received specimens of this species from Davidson, which were found in October, 1916, on Quercus macrocarpa in Sacra- mento. The determination was made by Davis. Below are a few descriptive notes to supplement Williams' description listed above. Alate viviparous female. — Antennae about as long as body, III the longest segment, followed by IV, VI, and V. VI spur is slightly longer than the base. The antennae are rather slender as compared 26 MISCELLANEOUS STUDIES with other species of this genus. Primary sensoria are present on V and VI as usual, and accessory sensoria on VI. There are about seven secondary sensoria oil III (fig. 262), which are more or less oval to circular, and located on the basal two-thirds of the segment. The cornicles, cauda, and anal plate are typical of the genus. Measurements: Body length 1.28 to 1.37 mm., antenna total 1.41 mm., Ill 0.459 mm., IV 0.306 mm., V 0.264 mm., VI 0.289 mm. (base 0.119 mm., spur 0.17 mm.), cornicles 0.68 mm., wing length 2.074 to 2.414 mm., width 0.68 to 0.833 mm. The two dusky transverse bands across the fore wings (fig. 263) constitute the most distinguishing character. The branching of the third discoidal is quite variable. 18. Myzocallis punctatus (Monell) Monell, U. S. Geol. Geog. Surv., Bull. 5, p. 31, 1879. Callipterus (orig. desc.). Clarke, Can. Ent., vol. 35, p. 249, 1903. Callipterus Jiyalinus Monell (list). Essig, Pom. Jour. Ent., vol. 4, p, 762, 1912. M. hyalinus (Monell) (list). Record. — Quercus imbricata, Berkeley (Clarke). This is a doubtful species, reported only by Clarke from Quercus imbricata in Berkeley. It is the author's opinion that this is the same species listed by Davidson as M. quercus (Kalt.). 19. Myzocallis maureri Swain Figures 55, 56, 266 Swain, Trans. Am. Ent. Soc., vol. 44, p. 4, 1918 (orig. desc.). Records.— Quercus agrifolia, Berkeley (Swain) ; Quercus Icelloggii, Julian, San Diego County (Swain). This species has been taken in Berkeley and in the Cuyamaca Mountains of San Diego County by the author. Essig has also taken it in Berkeley. It is never abundant, but the author has observed it several times and in several places in the localities mentioned. 20. Myzocallis pasaniae Dvdn. Figure 57 Davidson, Jour. Econ. Ent., vol. 8, p. 424, 1915 (orig. desc.). Eecords. — Pasania densiflora, Stevens Creek Canyon, Santa Clara County (Davidson), Berkeley, February, 1915 (Essig). This is a species found occasionally on tanbark oak in the San Francisco Bay region. The author has never taken it but has speci- mens from Davidson and Essig. A SYNOPSIS OF THE APHIDIDAE 27 21. Myzocallis quercus (Kalt.) Figures 31, 32, 58 Kaltenbach, Monog. d. Pflanzenlause, p. 98, 1843. Aphis (orig. dese.). Davidson, Jour. Econ. Ent., vol. 2, p. 302, 1909. Callipterus (list). Davidson, Jour. Econ. Ent., vol. 3, p. 376, 1910. Callipterus (list). Davidson, Pom. Jour. Ent., vol. 3, p. 399, 1911. Callipterus (list). Essig, Pom. Jour. Ent., vol. 4, p. 762, 1912 (list). Davidson, Jour. Econ. Ent., vol. 7, p. 130, 1914 (desc.). Records. — Quercus agrifolia; Stanford University, San Jose, Penryn, Placer County (Davidson) ; Q. lobata, Santa Clara County (Davidson) ; Berkeley, 1915 (Essig); Q. pedunculata, Berkeley, August, 1914; Q. douglasii, Stanford Univer- sity, November, 1910, April, 1911 (Morrison); Q. robur, Oakland (Davidson). This is a variable species more or less common in the San Fran- cisco Bay region and in the Sacramento Valley on various species of oaks. When he first reported it Davidson was doubtful of its identity. Later, however, it was identified by Peter Van der Goot5 as this species. 22. Myzocallis ulmifolii (Monell) Figure 59 Monell, U. S. Geol. Geog. Surv., Bull. 5, p. 29, 1879. Callipterus (orig. desc.). Davidson, Jour. Econ. Ent., vol. 2, p. 301, 1909. Callipterus (list). Davidson, Jour. Econ. Ent., vol. 3, p. 376, 1910. Callipterus (list). Essig, Pom. Jour. Ent., vol. 4, p. 762, 1912 (list). Records. — Ulmus sp., Stanford University (Davidson), "Ulmus americana, Wal- nut Creek, October, 1913 (Davidson). Davidson reports this as common on elms in the San Francisco Bay region. However, the author has never collected it. The follow- ing brief descriptive notes are from an alate viviparous female, taken in Walnut Creek by Davidson. The most distinguishing character is the presence of a pair of small but prominent tubercles on the mid- dorsum of the first and second abdominal segments. The usual primary and accessory sensoria are present on V and VI. Secondary sensoria (fig. 59) are present on the basal one-half to two-thirds of III. These are transversely linear or oval, and number about six. The cornicles are very short, being fully as broad at the apex as long. Cauda and anal plate normal. Wings normal, radial vein indistinct, first discoidal curving toward base of wing. Body length 1.836 mm., width of thorax 0.578 mm., antennae total 1.309 to 1.326 mm., Ill s In 1917 George Shhrji (Ent. News, vol. 27, February, 1917) described three species, M. essiggi n.sp., M. woodworthi n.sp., and M. hyalinus (Monell), all of which are undoubtedly but varieties of this species, M. quercus (Kalt.). 28 MISCELLANEOUS STUDIES 0.442 mm., IV 0.255 to 0.272 mm., V 0.221 to 0.2465 mm., VI 0.255 mm. (base 0.136 mm., spur 0.119 mm.), cornicles height 0.034 mm., diam- eter at apex 0.034 mm., wing length 1.581 to 1.768 mm., width 0.663 to 0.68 mm., expansion 3.825 mm. 8. Genus Chromaphis Walker Walker, The Zoologist, p. 2001, 1870. Type Lachnus juglandicola Kalt. 23. Chromaphis juglandicola (Kalt.) Figures 34, 35 Kaltenbach, Monog. d. Pflanzenlause, p. 151, 1843. Lachnus (orig. desc.). Essig, Pom. Jour. Ent., vol. 1, p. 51, 1909. Callipterus (desc. vivi.). Essig, Pom. Jour. Ent., vol. 4, p. 763, 1912 (list). Davidson, U. S. Dept. Agr., Bull. 100, pp. 2-19, 1914 (desc. all forms). Records. — Juglans regia; San Francisco Bay region, southern California. This walnut aphis is the most abundant and injurious of the species attacking walnut in California. It is more or less abundant throughout the San Francisco Bay region, while in southern Cali- fornia during certain seasons it is an important pest. Davidson (1914) has described all the forms and studied the life history care- fully, so but little comment is necessary. In 1915 the author observed the young stem mothers on March 22 in Sunnyvale, Santa Clara County. Three weeks later the second generation was well advanced. From the first of May on, in 1916, the viviparae were abundant on walnuts throughout San Diego County, from nursery stock in San Diego to a few cultivated trees at Santa Ysabel (altitude 3000 feet). From the middle of October until well into December, 1916, the sexuales were found throughout Los Angeles and Riverside counties. 9. Genus Callipterus Koch Koch, Die Pflanzenlause, p. 208, 1855. Type Aphis juglandte Kalt. The two members of this genus in California have been considered heretofore as species of Monellia Oestlund (genus 10), but according to Davis6 they can not be so considered for in Monettia the wings are laid flat on the abdomen when at rest. This is found only in M&nellia caryella (Fitch). Incidentally it may be remarked that the species known by that name in California does not have that habit, so should really be placed in this genus, Callipterus Koch. However, as it is identical with eastern specimens, except for this habit, the author 6 Essig, E. O., Beneficial and Injurious Insects of California, Mon. Bull. Cal. Comm. Hort., vol. 4, p. 83, 1915. A SYNOPSIS OF THE APHIDIDAE 29 has thought best to retain it in Monellis, at least for the time being. KEY TO CALIFORNIA SPECIES 1. VI spur about equal to or slightly longer than VI base. Tibiae mostly pale. caryae Monell — VI spur shorter than VI base. Tibiae entirely dark. Considerably larger than preceding species calif ornicus (Essig) 24. Callipterus californicus (Essig) Figures 63, 64 Essig, Pom. Jour. Ent., vol. 4, p. 767, 1912. Monellia (orig. desc.). Davidson, U. S. Dept. Agr., Bull. 100, p. 34, 1914. Monellia (list, key to walnut aphids). Records. — Juglans californica (California black walnut) ; Santa Paula. In 1912 Essig described this species from specimens taken near Santa Paula in July, 1911. No other definite collections are known to the writer, although Essig reports it as more or less abundant on the California black walnut throughout the southern part of the state. Davidson has not found it in the San Francisco Bay region, nor has the author ever observed it, either in the bay region or in southern California. 25. Callipterus caryae Monell Figures 65, 66 Monell, U. S. Geol. Geog. Surv., Bull. 5, p. 31, 1879 (orig. desc.). Clarke, Can. Ent., vol. 35, p. 249, 1903 (list). Davidson, Jour. Econ. Ent., vol. 2, p. 301, 1909 (list). Davidson, Jour. Econ. Ent., vol. 3, p. 376, 1910 (list). Essig, Pom. Jour. Ent, vol. 4, p. 764, 1912. Monellia (list). Davidson, U. S. Dept. Agr., Bull. 100, pp. 19-26, 1914. Monellia (dese. all forms). Records. — Juglans regia, J. californica; Berkeley, Stanford University, San Jose, San Francisco Bay region. This species is more or less common in the San Francisco Bay region on walnuts. Davidson has described all the forms and noted its life history. The author has not taken the species. 10. Genus Monellia Ostluml Oestlund, Minn. Geol. Nat. Hist. Surv., Bull. 4, p. 44, 1887. Type Aphis caryella Fitch. This genus, as described by Oestlund, differs from Callipterus par- ticularly in the position of the wings when the insects are at rest. In Callipterus they are held roof-like over the body as is usual in aphids. but in Monellia they are laid flat on the abdomen. It includes but the one species, M. caryella (Fitch). 30 MISCELLANEOUS STUDIES 26. Monellia caryella (Fitch) Figures 25, 67, 68 Fitch, Insects N. Y., vol. 1, p. 163, 1855. Aphis (orig. desc. apt. vivL). Fitch, Ins. N. Y., vol. 3, p. 448, 1856. Callipterus (first desc. ala. vivi.). Davidson, Jour. Econ. Ent., vol. 7, p. 132, 1914 (list). Davidson, U. S. Dept. Agr., Bull. 100, pp. 26-34, 1914 (desc. all forms). Records. — Juglans calif ornica, J. Nigra, J. regia; San Jose, Walnut Creek (Davidson) ; Stanford University, May to June, 1915. A more or less common species on both the native black walnut, and the cultivated walnut in the San Francisco Bay region. This species, while very similar to the preceding species, is probably the more common of the two. The following table of differences is taken from Davidson:7 Form Alate viviparous female Callipterus caryae Monell Monellia caryella (Fitch) Pupa of viviparous female Oviparous female Antennal joint III very slightly thickened bas- ally. Sensoria on antennal joint III occupying basal half or two- thirds. Antennal joint VI and its spur or filament subequal, or VI less than spur. Dusky knee spots often present. Four longitudinal rows of capitate spines. Smaller than viviparous female. Four longitudinal rows of cipitate spines. Antennal joint III quite noticeably thickened * for its basal half. Sensoria on antennal joint III occupying basal third. Antennal joint VI one- third as long again as its spur or filament. Dusky knee spots absent. Six longitudinal rows of capitate spines. Larger than viviparous female. Six longitudinal rows of capitate spines. This species is distinct from the preceding and according to Mor- rison, who has examined eastern species, is structurally identical except in the matter of the wings. He writes as follows : i Davidson, W. M., Walnut aphides in California, II. S. Dept. Agr., Bull. 100, p. 28, 1914. A SYNOPSIS OF THE APHIDIDAE 31 I made a very careful study of specimens from California, sent me by David- son, and of specimens collected both in Indiana and New York (type locality). I was unable to find any structural differences that would definitely separate the two lots of specimens, with the exception of the position of the wings. These are laid flat when at rest in the eastern specimens, but are not so in the Californian specimens, according to Davidson. In spite of this apparent agreement, I feel that the two must be distinct. If this is the case, that the wings are not laid flat at rest, this species must belong to the genus Callipterus, and therefore cannot be Monellia caryella (Fitch). However, the author has not had an opportunity to study this carefully, so leaves it as it is, calling this California species Monellia caryella (Fitch). Because of the fact that all the species of aphids on walnut are so closely related, and so very similar in structure, a key to separate them, one from another, is given here. This key is adapted from Davidson.8 1. Cornicles quite evident, about as long as wide. Chromaphis juglandicola (Kalt.) — Cornicles barely perceptible, considerably wider than long * 2 2. Tibiae of alate viviparae entirely dusky Callipterus calif ornicus (Essig) — Tibiae of alate viviparae mostly pale 3 3. VI spur longer than VI base. Oviparous females with four longitudinal rows of capitate hairs Callipterus caryae Monell — VI spur shorter than VI base. Oviparous females with six longitudinal rows of capitate hairs Monellia caryella (Fitch) 11. Genus Callipterinella Van der Goot Van der Goot, Zur Systematic der Aphiden, 1913. Type Aphis (Callipterus) betularius Kaltenbach. 27. Callipterinella ammlata (Koch) Koch, Die Pflanzenlause, p. 1855. Chaitophorus (orig. desc.). Gillette, Jour. Econ. Ent., vol. 3, p. 367, 1910, Chaitophorus betulae (Buck- ton) (list). Davidson, Jour. Econ. Ent., vol. 10, p. 292, 1917 (desc.). Eecords. — Betula alba; Oakland, Walnut Creek (Davidson). This species has been reported by Davidson as infesting the leaves and shoots of the white birch in the San Francisco Bay region. It is unknown to the author. s Ibid., p. 35. 32 MISCELLANEOUS STUDIES Tribe Chaitophorini Wilson (Lachnidea Mordw. and Chaitopheri Mordw.) Wilson, Can. Ent., vol. 42, pp. 385-387, 1910. This tribe as considered by Wilson contains the following genera : Arctaphis, Chaitophorus, Symydobius, Thoniasia, and Sipha. The author has followed Wilson's classification, having added, however, two genera described later by Essig: viz., Micrella and Fullawaya. Essig's genus Eichochaitophorus is a synonym of Arctaphis Walker (see discussion under no. 27). Mordwilko's groups Lachnoidea and Chaitophori are both included in this one tribe. In the former, Mord- wilko includes Symydobius and Pterochlorus, and in the latter, Cladobius, Melanoxanthus, and Chaitophorus. Both Cladobius and Melanoxanthus are included in this paper in the tribe Pterocommini, being synonyms of the genus Pterocomnia Buckton. Following is a description of the tribe Chaitophorini as given by Wilson (op. cit.) : Antennae, except in Sipha, always six-segmented; in Sipha there are but five. Length variable; antennal tubercles wanting; antennae, legs, and body covered with hair-like bristles. Fore wings with two oblique veins and cubitus always twice forked; hind pair with two cross veins. Nectaries (cornicles) variable in length and size, but never longer than one-tenth the length of the body. The genera in this tribe are somewhat similar to those in the tribe Callipterini, but are easily distinguished by the shorter and heavier antennae and legs, as well as by the finer and more hair-like bristles. The following key to the Californian genera has been adapted from Wilson and Essig : 1. Spur of sixth antennal segment at least three times as long as the segment 2 — Spur not three times as long as the segment. Cauda broadly rounded and without knobbed tip 4 2. Spur more than five times as long as the segment; cornicles longer than the base of the sixth segment Chaitophorus Koch — Spur of sixth segment not more than five times as long as the segment; corn- icles not longer than the base of the sixth segment 3 3. Cauda a knob on a quadrangular base (fig. 69). Spur about five times as long as sixth segment Arctaphis Walker — Cauda tapering to a blunt tip which is usually straight across, not being rounded or constricted at the base (fig. 70). Spur but slightly more than three times as long as the sixth segment _ Micrella Essig 4. Spur of sixth segment shorter or scarcely longer than the segment; antennae nearly as long as the body Symydobius Mordwilko — Spur considerably longer than sixth segment; antennae about one-half the length of the body _ 5 5. Cornicles absent ; body with lateral tubercles Fullawaya Essig — Cornicles present ; lateral body tubercles wanting „ Thomasia Wilson A SYNOPSIS OF THE APHID1DAE 33 Genus Chaitophorus Koch Koch, Die Pflanzenlause, p. 1, 1854. Type Aphis aceris Linn. There are at present no species of this genus in California; most of the species hitherto placed in it are now considered as belonging to the genus Thomasia Wilson. 12. Genus Arctaphis Walker Walker, The Zoologist, p. 2000, 1870. Type aphis populi Linn. This genus as defined by Wilson is represented in California by two species: A. viminalis (Monell) and A. populifolii (Essig). The latter was placed by Essig in a new genus, Eichochaitophorus, but there is not enough difference between these to warrant a new genus. KEY TO CALIFORNIA SPECIES 1. Wings hyaline. Three-nine large sensoria on third antennal segment (fig. 71). IV half as long against as V populifolii (Essig) — Wings subhyaline. About ten rather small sensoria on III. IV but very little longer than V viminalis (Monell) 28. Arctaphis populifolii (Essig) Figures 69, 71 Essig, Pom. Jour. Ent., vol. 4, p. 722, 1912. Eichochaitophorus (orig. desc.). Davidson, Jour. Econ. Ent., vol. 3, p. 375, 1910. Chaitophorus populifoliae (Fitch) (desc. male). Davidson, Pom. Jour. Ent., vol. 3, p. 399, 1911. Chaitophorus populifoliae (Fitch) (list). Records. — Populus trichocarpa, Santa Paula (Essig), Berkeley, September, 1915; Populus fremontii, Stanford University and Penryn, Placer County (David- son) ; Menlo Park, San Mateo County, October, 1914 (Morrison) ; Berkeley, Sep- tember, 1915; El Cajon, San Diego County, June, 1916; Kiverside, October, 1916. In 1912 Essig described this species from specimens taken on Populus trichocarpa at Santa Paula, and placed it in a new genus, Eichochaitophorus. He separated this genus from Arctaphis for the following reasons : According to Wilson the cauda [in Arctaphis] is a knob on a quadrangular base. The anal plate is broadly rounded. In the new genus [Eichochaitophorus] the style has a distinct neck and is situated on a very distinct conical base. The anal plate is deeply notched in the middle so as to make it somewhat forked as in the genus Callipterus. 34 MISCELLANEOUS STUDIES Although the anal plate is somewhat notched, there is scarcely difference enough to warrant the forming of a new genus. In fact, in many specimens one cannot tell whether or not a notch is present. As to the cauda, consisting of the tip, a distinct neck, and a distinctly conical base, this is not greatly different from a cauda consisting of a knobbed tip on a quadrangular base. The only practical difference is in the base, being conical in one and quadrangular in the other. In populifolii (Essig) the base seems to be conical, yet one cannot be certain unless the specimen is mounted exactly. This species, A. populifolii (Essig), as stated above, was described from specimens taken on Popuhis trichocarpa at Santa Paula. In 1910 Davidson found a species on Populus fremonti at Stanford Uni- versity, and the following year at Penryn, Placer County, which he listed as Chaitophorus populifoliae (Fitch). A careful study of specimens from Davidson and the cotypes of Essig 's species convinced the author that they were identical. Morrison writes that Davidson's specimens are not C. populifoliae (Fitch), so Essig 's species is distinct. In September, 1915, the author observed a great number of specimens of this species on a weeping elm (TJlmus sp.) in Berkeley, which was in close proximity to some populars. However, none were seen to be feeding on the elm, all being restless and wandering over the leaves and branches. In southern California this is often found infesting the empty galls of Thecabms populimonilis Riley, such having been observed in San Diego and Riverside counties. 29. Arctaphis viminalis (Monell) ? Monell, U. S. Geol. Geog. Surv., Bull. 5, p. 31, 1879. Callipterus (orig. desc.). Clarke, Can. Ent., vol. 35, p. 248, 1903. Chaitophorus (list). Davidson, Jour. Econ. Ent., vol. 3, p. 375, 1910. Chaitophorus (list). Davidson, Pom. Jour. Ent., vol. 3, p. 398, 1911. Chaitophorus (list). Essig, Pom. Jour. Ent., vol. 4, p. 716, 1912. Thomasia (list, key to Califor- nian species of Thomasia). Patch, Maine Agr. Exp. Sta., Bull. 213, p. 80, 1913. CJiaitophorus (desc.). Records — Salix spp. ; Watsonville, Santa Cruz County, and Newcastle, Placer County (Clarke); Penryn, Placer County, and Stanford University (Davidson). This species has been reported from Placer, Santa Clara, and Santa Cruz counties on various species of willow. The true Chai- tophorus viminalis Monell is an Arctaphis, but whether or not the western species is the same as the eastern is a question. The author has never seen specimens of either and is therefore unable to make A SYNOPSIS OF THE APHIDIDAE 35 any further comment. He once thought the western spe*cies was iden- tical with Thomasia salicicola (Essig), to which Morrison considers it very closely related, but Davidson assures him the two are distinct. 13. Genus Micrella Essig Essig, Pom. Jour. Ent., vol. 4, p. 716, 1912. Type M. monella n.sp. 30. Micrella monella Essig Figures 70, 72 Essig, Pom. Jour. Ent., vol. 4, p. 717, 1912 (orig. desc.). Becords. — Salix lasiolepis, Oxnard (Essig); S. laevigata, Santa Paula (Essig). This species was taken twice by Essig, who described it, in 1910 near Oxnard, and in 1911 near Santa Paula. Since then it has never again been found. The author has had access to cotype specimens in Essig 's collection. 14. Genus Fullawaya Essig Essig, Pom. Jour. Ent., vol. 4, p. 735, 1912. Type F. saliciradicis n.sp. 31. Fullawaya saliciradicis Essig Figure 75 Essig, Pom. Jour. Ent., vol. 4, p. 737, 1912 (orig. desc.). Eecord. — Salix laevigata, Santa Paula, August, 1911 (Essig). On the roots of Mallow near Santa Paula, Essig once found a large number of aphids, the greater part of which were apterae, although a few alates were present. Unable to identify them with any known species, or to fit them into any genus, he described them as this species. Since then they have not been taken. The author has had access to cotype specimens in Essig 's collection. 15. Genus Thomasia Wilson Wilson, Can. Ent., vol. 42, p. 386, 1910. Type Chaitophorus populicola Thomas. This genus is separated from Chaitophorus principally by the comparative lengths of the antennae and the comparative lengths of the spur of the sixth antennal segment. In Chaitophorus (type Aphis aceris Linn.) the antennae are almost as long as the body, and the spur of the sixth segment is over five times as long as the base. In this genus the antennae are but about one-half as long as the body, and VI spur is but slightly longer than VI base. 36 MISCELLANEOUS STUDIES KEY TO CALIFORNIA SPECIES 1. Wings hyaline 2 - Wings with veins clouded (fig. 275) populicola (Thomas) 2. Ill longer than VI (including spur) negundinis (Thomas) — Ill not longer than VI (including spur) 3 3. IV with secondary sensoria crucis Essig — IV without secondary sensoria salicicola Essig 32. Thomasia crucis Essig Figure 76 Essig, Pom. Jour. Ent., vol. 4, p. 742, 1912 (orig. desc.). Records. — Salix macrostaohya, Santa Paula, August, 1911 (Essig). Essig once found this species on the leaves of willow near Santa Paula. Since then it has never again been taken. The author has had access to cotype specimens in Essig 's collection. 33. Thomasia negundinis (Thomas) Thomas, 111. Lab. Nat. Hist., Bull. 2, p. 10, 1878. Chaitophorus (orig. desc.). Sanborn, Kan. Univ. Sci., Bull. 3, p. 35, 1904. Chaitophorus (desc.). Davidson, Jour. Econ. Ent., vol. 3, p. 376, 1910. Chaitophorus (list). Essig, Pom. Jour. Ent., vol. 4, p. 716, 1912 (list). Records. — Acer negundo, Stanford University (Davidson) ; Salt Marshes, Palo Alto, May, 1912 (Morrison). This species of Thanuisia is quite common on box elder in the vicinity of Stanford University and Palo Alto. The author has never taken specimens, nor had access to any. Morrison writes that * although he has never had access to eastern specimens of T. negundinis (Thos.) for comparison he is not able to convince himself that the western species is negundinis. The author is unable to form any opinion at present, having never seen specimens, hence lists the species as Davidson has done. 34. Thomasia populicola (Thomas) Figures 77, 275 Thomas, 111. Lab. Nat. Hist, Bull. 2, p. 10, 1878. Chaitophorus (orig. desc.). Essig, Pom. Jour. Ent., vol. 1, p. 98, 1909. Chaitophorus (desc.). Essig, Pom. Jour. Ent., vol. 4, p. 716, 1912 (list). Records. — Populus spp., Salix spp., Santa Paula (Essig) ; Eiverside, May, 1917; Populus sp., Canton, Broadwater County, Montana, July, 1915, R. W. Haegele; Edna Canon, Boxelder County, Utah, August, 1916, R. W. Doane. A SYNOPSIS OF THE APHIDIDAE 37 This species has been reported by Essig from Ventura County. The author has never taken the alates, but has had the opportunity of examining Essig 's specimens, and specimens from Montana and Utah taken by Haegele and Doane. It is easily distinguished from other members of the genus by the broad, dark wing veins. 35. Thomasia salicicola (Essig) Figure 78 Essig, Pom. Jour. Ent., vol. 3, p. 532, 1911. Chaitophorus (orig. desc.). Davidson, Jour. Eeon. Ent., vol. 3, p. 375, 1910. ChaitopJiorus nigrae Oest- lund (?) (list). Davidson, Pom. Jour. Ent., vol. 3, p. 398, 1911. Chaitophorus nigrae Oest- lund (?) (list). Essig, Pom. Jour. Ent., vol. 4, p. 619, 1912 (note). Essig, Pom. Jour. Ent., vol. 4, p. 716, 1912 (list). Eecords. — Salix laevigata, Santa Paula (Essig), Salix nigra, Lakeside, San Diego County, April, 1916; Populus trichocarpa, Santa Paula (Essig); Salix sp., Sau Jose, Stanford University, Penryn, Placer County (Davidson), Fillrnore, Ven- tura County, March, 1911 (Essig). Essig reported this from Ventura County, and the author has found it in San Diego County. It was observed to be in large colonies on the leaves and leaf petioles of the tender growth of willow, in company with Siphocoryne carpreae (Fabr.). Specimens taken by Davidson and listed as Chaitopkorus nigrae Oestlund prove to be identical with this species. 16. Genus Symydobius Mordwilko Mordwilko, Bap. Lab. Zool. Kap. Imp. Varch. Univ., 1895. Type Aphis oblonga Heyden. KEY TO CALIFORNIA SPECIES 1. Anal plate half -moon-shaped 2 — Anal plate bilobed (fig. 271) ; cornicles pale, appearing white in life; antennae with about six to eight secondary sensoria on III, and one or two on IV (fig. 272 ) chrysolepis Swain 2. Spur of VI but a short thumb-like projection ; sensoria on III numbering about six to ten; none on IV agrifoliae Essig — Spur of VI longer, being equal to or longer than base of VI ; fifteen to twenty sensoria on III, one or two on IV (figs. 73, 74) 3 3. Antennae for the most part dark, being dark brown or black; spur and base of VI equal, lateral abdominal tubercles present in apterae. macrostachyae Essig — Antennate for the most part pale, being light brown or amber; spur of VI usually slightly longer than base; apterae without lateral abdominal tubercles salicicorticis Essig 38 MISCELLANEOUS STUDIES 36. Symydobius agrifoliae Essig Essig, Univ. Calif. Publ. Entom., vol. 1, pp. 311-317, 1917 (orig. desc.). Eecords. — Quercus agrifolia; Santa Paula (Essig). This interesting aphid was taken in Ventura County on live oak during 1911. It differs from other members of this genus in the extremely short spur of the sixth antennal segment. The coloration is very similar to that of the next species, but the length of VI spur and the fact that the anal plate is not bilobed serves to distinguish it. 37. Symydobius chrysolepis Swain Figures 269 to 274 Swain, Trans. Am. Ent. Soc., vol. 44, p. 6, 1918 (orig. desc.). Eecords. — Quercus chrysolepis; Alpine, San Diego County (Swain). This is a medium sized, brownish colored aphid found in 1916 infesting the terminal twigs and leaf petioles of maul oak in San Diego County. Its pale white cornicles are very conspicuous, and serve as a distinguishing character. The anal plate is bilobed, a char- acter not found in other members of the genus, and one which may be sufficient for the separation of the species (and 8. albisiphus Davis, in which the anal plate is also bilobed) from Symydobius into a new genus. However, the author believes it best to retain them in this genus at present. The apterous females were found to be heavily parasitized by the chalcid fly, Closterocerus utahensis Crawford var. calif ornicus Girault. 38. Symydobius macrostachyae Essig Figure 73 Essig, Pom. Jour. Ent., vol. 4, p. 727, 1912 (orig desc.). Eecords. — Salix macrostachya ; Santa Paula (Essig), Fresno, June, 1915. Twice has this species been taken, once by Essig near Santa Paula and once by the author along the San Joaquin River near Fresno. It is found in fairly large colonies on the younger stems of willow. These colonies consist for the most part of apterae, only a very few alates being present. A SYNOPSIS OF THE APHIDIDAE 39 39. Symydobius salicicorticis Essig Figure 74 Essig, Pom. Jour. Ent., vol. 4, p. 731, 1912 (orig. dese.). Record. — Salix laevigata; Santa Paula (Essig). Together with specimens of Fullauwya saliciradicis Essig, this was taken on willow along the Santa Clara River near Santa Paula in August, 1911. The colonies are found on the bark near the surface of the ground either just above or just below it. Essig reports that it is preyed upon quite extensively by the larvae of an undetermined species of syrphus fly. The author has had access to cotype specimens in Essig 's collection. Group Lachnina Passerini Passerini, Gli Afidi, 1860. In this group there are included two tribes, Lachnini Del Guercio and Pterocommini Wilson, following Wilson. Mordwilko places but the one tribe Lachnini in this group, including the genus Pterocomma Buckton in the tribe Chaitophori. However, to the author the group- ing followed here seems more natural. The following key is adapted in part from Borner (Sorauer, Pflanzenkrankheiten, vol. 3, p. 665, 1913) : Sixth antennal segment with a short, thick (thumb-like) projection. Cornicles conical (fig. 91) or wart-like. Empodial hair short, and oftentimes indistin- guishable (fig. 79) Tribe Lachnini Sixth antennal segment with a slender projection (VI spur) which is about as long as the segment (VI base). Cornicles cylindrical or clavate (figs. 81, 82). Empodial hair practically as long as the claws (fig. 80). Tribe Pterocommini Tribe Pterocommini Wilson Wilson, Ann. Ent. Soc. Am., vol. 8, pp. 347-358, 1915. This tribe, as considered by Wilson, contains but the one genus, Pterocomma Buckton. In a former paper (Can. Ent., vol. 43, p. 384, 1910) he recognized two genera : the one, Melanoxantherium Schoute- den, in which the cornicles were swollen or vasiform, and the other, 40 MISCELLANEOUS STUDIES Pterocwnnia Buckton, in which the cornicles were cylindrical. He states in his later paper : "... after having further studied the group I am of the opinion that such a divsion is illogical, and if a division is necessary each species should form a different genus. It, therefore, seems more practical to confine all the species to a single genus. ' ' The characters of this tribe and genus are as follows : Antennae with six segments and reaching near the base of the abdomen. Wings normally with venation as in Aphis. Nectaries [cornicles] short, but clavate. Cauda short and broadly rounded at the tip as in Lachni?ii. Entire body, antennae, and legs covered with long hairs as in Lachnini. As has already been pointed out by Oestlund, this group appears intermediate between the Clw.Uo- phorini and the Lachnini. Their habits and actions being in different ways similar to both. 17. Genus Pterocomma Buckton Buckton, Monog. Brit. Aphides, vol. 2, p. 143, 1879. Type P. pilosa Buckton. KEY TO CALIFORNIA SPECIES 1. Cornicles abruptly constricted at distal end, and without a distinct flange (fig. 81), the diameter of the opening being less than the diameter of the smallest part of the cornicle. Wing veins broad and shaded. flocculosa (Weed) — Cornicles not so abruptly constricted and with a distinct flange. Wing veins normal 2 2. Cornicles about twice as long as their greatest diameter ....smithiae (Monell) — Cornicles considerably longer than greatest diameter, and longer than hind tarsus populifoliae (Fitch) 40. Pterocomma flocculosa (Weed) Figure 81 Weed, Insect Life, vol. 3, p. 291, 1891. Melanoxanlhus (orig. desc.). Wilson, Ann. Ent. Soc. Am., vol. 8, p. 350, 1915 (desc.). Records. — Salix sp., Berkeley, March, 1915; 1916 (Essig). In his paper on Pterocomma Wilson states that this species does not occur on the Pacific Coast. However, in March, 1915, the author found it rather abundantly on willow on the campus of the University of California in Berkeley. During the 1916 season Essig observed it to be quite common in Berkeley. The species is easily recognized in life by the white cottony flocculence covering the colonies on the bark. A SYNOPSIS OF THE APHIDIDAE 41 41. Pterocomma populifoliae (Fitch) Figures 82. 83 Fitch, Cat. Homop. N. Y., p. 66, 1851. Aphis (orig. dese.). Davidson, Jour. Econ. Ent., vol. 2, p. 300, 1909. Cladobius rufulus n.sp. (desc.). Davidson, Jour. Econ. Ent., vol. 3, p. 375, 1910. Cladobius rufulus Dvdn. (list). Essig, Pom. Jour. Ent., vol. 4, p. 786, 1912. Melanoxantherium rufulum (Dvdn.) (desc.). Wilson, Ann. Ent. Soe. Am., vol. 8, p. 353, 1915. Pterocomma populea (Kalt.) (desc.). Baker, Can. Ent., vol. 48, pp. 280-282, 1916 (desc.). Records. — Salix sp. ; Stanford University (Davidson); Santa Paula (Essig); Walnut Creek, March, 1915 (Davidson) ; Grossmont, San Diego County, March, 1916; Lakeside, San Diego County, April, 1916; Stanford University, May, 1912 (Morrison); Populus sp. ; Stanford University (Davidson); Palo Alto, March, 1915; Populus caroliniana, Banning, Riverside County, April, 1917. This is a widely distributed species in California on various species of poplars and willows. Davidson first found it in 1909, describing it as a new species. In 1915 Wilson stated that it was synonymous with P. populea (Kalt.), but specimens sent him by the author he determined as P. bicolor (Oestlund). According to his paper the cornicles of populea (Kalt.) are about equal in length to the hind tarsi. Californian specimens have the cornicles considerably longer than the hind tarsi, but not twice as long as he states they are in bicolor (Oestlund). His figures of the antennae show that in populea VI base and spur are subequal, and in bicolor the spur is considerably longer than the base. The latter is true for the Californian species. His color notes of populea fit the Californian species very well. Baker identified Aphis populifoliae Fitch as a Pterocomma and places rufulus (Davidson) as a synonym. From a study of specimens taken in Santa Paula, Grossmont, Lakeside, Stanford University, and Wal- nut Creek, the author finds that Baker's description of populifoliae fits this species very well. Below are the measurements in microns of four alate specimens, together with the measurements of cornicles, antennae, and hind tarsi of one from Lakeside. (This was preserved for several months in alcohol before being mounted for study, and had shrunk considerably.) An examination of the following table shows that in the California specimens the cornicles are always considerably longer than the hind tarsi, but never twice as long, and that the spur of six is always longer than the base, except in one case. This specimen is considerably 42 MISCELLANEOUS STUDIES .2 "5, co co in Tf< a «B 2 s w* ^ t~t- O •<+! (M O O O O rH CM CM (M '§ -^"S m .a ^3 •fi $ O ® S 05 .S ic «! -3 OQ ei > S rP « CS «H *? «H rs 2 s 83 -_ cj c 'Jl S ^ e« A SYNOPSIS OF THE APHIDIDAE 43 smaller than the others and has many more secondary sensoria, being a male. From this evidence this species is the same as Baker lists as P. populifoliae (Fitch) and should be so considered. The author has reared a number of specimens of a species of Aphidiiw from material obtained near Stanford University in May, 1915. 42. Pterocomma smithiae (Monell) Monell, U. S. Geol. Geog. Surv., Bull. 5, p. 32, 1879. Chaitophorus (orig. desc.). Davidson, Jour. Econ. Ent., vol. 2, p. 300, 1909. Cladobius salicti (Harris) (list). Davidson, Jour. Eeon. Ent., vol. 3, p. 375, 1910. Cladobius salicti (Harris) (list). Essig, Pom. Jour. Ent., vol. 4, p. 786, 1912. Melanoxantherium salicti (Harris) (list). Wilson, Ann. Ent. Soc. Am., vol. 8, p. 355, 1915 (desc.). Records. — Salix spp., Stanford University (Davidson, Morrison). Both Davidson and Morrison have taken this species in the vicinity of Stanford University on various species of willow. According to Wilson, with whom Morrison and Baker agree, this is P. smithiae (Monell), the salicti of Harris being synonymous. The sexuales were observed by Davidson in October, the eggs hatching in January. Tribe Lachnini Del Guercio Del Guercio, Eedia, vol. 5, 1908. This tribe is represented in California by three genera, viz., Essig- ella Del Guercio, Tuberolachnus Mordwilko, and Lachnus Burmeister, while there are six genera included in the tribe as it is here considered. Following is a brief characterization of the tribe adapted from Mord- wilko : The body and appendages are very hairy, and usually quite large. The cauda is absent, the cornicles cupola-shaped, being black or brown in color. Sometimes they are reduced to mere pores or not fully developed [Lachnus taxifolia Swain]. The antennae in general are not longer than the head and thorax, six- jointed [except in Essigella Del Guercio], with the spur of the sixth segment very short, not being as long as the segment itself. The beak is almost always elongated, generally reaching to or beyond the middle of the abdomen. All this group possess the anatomical peculiarity that the narrowed hind end of the stomach is covered with the intestine. The stigma of the fore wing is elongate linear [in Longi- stigma Wilson it reached past the tip of the wing (fig. 89)]. The cubitus is twice- branched. 44 MISCELLANEOUS STUDIES All the California species with the exception of Tuberolachnus vimi- nalis (Fonsc.), which lives on willow, are found on conifers — Firms sp., Pseudotsuga sp., or Picea, sp. Following is a key to the genera, adapted from Del Guercio, Wil- son and Essig. In this key are included not only the California genera but the other three as well, in that an understanding of the characters is thus made easier. 1. Antennae six-segmented 2 — Antennae five-segmented (fig. 83) Essigella Del Guercio 2. Stigma exceptionally long, reaching beyond the tip of the wing (fig. 84). Longistigma (Wilson) — Stigma not exceptionally long, not reaching beyond the tip of the wing (fig. 85 ) 3 3. First joint of the hind tarsus much shorter than half the second (fig. 86) .... 4 — First joint of the hind tarsus equal to or slightly longer than half the second (fig. 87) -. Eulachnus Del Guercio 4. Abdomen with horn-like tubercle on median dorsum between the cornicles, (Sometimes this cannot be made out in specimens mounted in balsam, but it is always readily discernible in fresh or alcoholic material). Tuberolachmus Mordwilko — Abdomen without horn-like tubercle 5 5. Bases of first and second discoidal close together; third discoidal often very faint; wings slightly if ever clouded (fig. 85) Lachnus Burmeister — Bases of first and second discoidals not so close together as in Lachnus Burm. ; third discoidal plain; wings often darkly clouded Pterochlorus Rondani 18. Genus Essigella Del Guercio Del Guercio, Eev. di patal. veg., vol. 3, p. 328, 1909. Type Lachnus cali- fornicus Essig. 43. Essigella calif ornica (Essig) Figures 3, 5, 83 Essig, Pom. Jour. Ent., vol. 1, p. 1, 1909. Lachnus (orig. desc.). Del Guercio, Pom. Jour. Ent., vol. 1, p. 73, 1909 (translation by C. F. Baker of Del Guercio 's paper listed above). Essig, Pom. Jour. Ent., vol. 4, p. 773, 1912 (list). Essig, Pom. Jour. Ent., vol. 4, p. 780, 1912 (desc.). Records. — Pinus radiata; Claremont, Los Angeles County, and Santa Paula (Essig); Pinus sabiniana, Stanford University, March, 1915; Pinus spp., Stan- ford University, March and April, 1912 (Morrison) ; Ontario, San Bernardino County, January, 1917. This curious little aphid, described by Essig from specimens taken in Claremont, Los Angeles County, on Pinus radiata, has since been found in several parts of the state. Wilson has taken it in Oregon on Pseudotsuga taxifolia, and Patch in Maine on Pinus strobus. It A SYNOPSIS OF THE APHIDIDAE 45 is a small, slender, long-legged aphid, that clings fast to the pine needles and is extremely difficult to see. However, if a branch of pine is struck sharply and with considerable force over a white paper or cloth, a large number of these aphids will jar off. 19. Genus Tuberolachnus Mordwilko Mordwilko, Ann. Mus. Zool. d. 1'Acad. Imp. Sci., vol. 13, p. 374, 1908. Type Aphis viminalis Fonsc. 44. Tuberolachnus viminalis (Fonsc.) Figure 86 / Boyer de Fonscolmbe, Ann. Ent. Soc. France, vol. 1O, p. 162, 1841. Aphis (orig. desc.). Davidson, Jour. Econ. Ent., vol. 2, p. 299, 1909. Lachnus (list). Davidson, Jour. Econ. Ent., vol. 3, p. 374, 1910. Lachnus (list). Davidson, Pom. Jour. Ent., vol. 3, p. 398, 1911. Lachnus dentatus Le Baron (list). Essig, Pom. Jour. Ent., vol. 4, p. 774 (772), 1912 (list). Records. — Salix spp., Stanford University and Penryn, Placer County (David- son); Ventura County (Essig); Stanford University, November, 1914; Berkeley, July, 1915; Eiverside, July, 1916. This extremely large aphid, which lives in large colonies on the branches of various species of willows, is found throughout the San Francisco Bay region, Sacramento Valley, and southern California, although it is not at all common. Davidson reports considerable parasitization by a species of Epherdius, and Essig infection from some bacterial or fungus disease. The large size and the presence of a dorsal abdominal tubercle are distinguishing characters. 20. Genus Lachnus Burmeister Burmeister, Handbuch d. Entomologie, p. 91, 1835. Type Lachnus faciatus, n.sp. This is the third largest genus of aphids in regard to the number of species in California. All the species are to be found on various conifers, usually feeding through the bark of the branches or trunk. Characters for distinguishing the species are hard to obtain, and those used by the author in the following key are of no value except with specimens of the alate viviparae. This key is not at all adequate, and is offered here merely as an aid. The author understands that Wilson is preparing a monograph of this genus, which will undoubt- edly prove quite valuable. 46 MISCELLANEOUS STUDIES KEY TO CALIFORNIA SPECIES 1. Beak reaching considerably beyond the third coxa 2 — Beak at most barely reaching to the third coxa 8 2. Beak reaching almost to or. even beyond the tip of the abdomen 3 — Beak not reaching to the tip of the abdomen 4 3. First joint of hind tarsus more than one-third as long as the second joint. Legs black except the base of the femora and a broad ring near the base of the tibiae ponderosa Williams — First joint of hind tarsus scarcely more than one-fourth as long as the second joint. Legs pale at the base of the femora and tibiae, black at tips. oregonensis Wilson 4. Body exceptionally Jarge, being over 4 mm. long, usually about 5 mm., and over 2 mm. wide _ 5 — Body of average size, being from 2.5 mm. to 3 mm. long, and from 0.75 to 1.2 mm. wide 7 5. Third segment of antennae with many sensoria (eight or more), (figs. 88, 89) 6 . — Third joint of antennae with but few or no sensoria, at most with one or two. First joint of hind tarsus a little less than half as long as the second. On Pinus sdbiniana sabinianus n.sp. 6. Third joint of antennae with about 8-12 sensoria (fig. 88). Tibiae with a pale ring near the base. First joint of hind tarsus scarcely more than one-third the length of the second. On Picea sp vanduzei n.sp. — Third joint of the antennae with 19-20 sensoria (fig. 89). Tibiae without pale ring near base. First joint of hind tarsus almost one-half the length of the second. On Pinus sp. and Abies sp ferrisi Swain 7. Beak not reaching to the middle of the abdomen. Segment three of the antennae almost as long as the fourth, fifth, and sixth together. Apex of stigma meeting the margin of the wing in an acute angle, and not terminated by a distinct vein (fig. 92). On Pseudotsuga taxifolia. pseudotsugae Wilson — Beak reaching beyond the middle of the abdomen. Third antennal segment not nearly so long as the fourth, fifth, and sixth together. Apex of stigma meeting the wing margin in an obtuse angle, and terminated by a distinct vein (fig. 93). Apterous viviparous females with a distinctive pattern on dorsum of abdomen. On Thuya occidentalis tujafilinus (Del Guercio) 8. First joint of hind tarsus longer than one-fourth the second 10 — First joint of hind tarsus less than one-fourth the second 9 9. Third antennal segment without sensoria (fig. 94). Body robust, being of the usual Lachnus shape. Third discoidal twice-branched, only occasionally once-branched. On Abies grandis occidentalis Davidson — Third antennal segment with several irregular sensoria (fig. 95). Body long and narrow, being somewhat the shape of Essigella calif ornica (Essig). Third discoidal simple or once-branched. On Pinus sp. pini-radlatae Davidson 10. Cornicles very poorly developed, seemingly absent in some cases (fig. 103). Segment three of antennae with five-seven large circular sensoria which are hardly distinguishable (fig. 106). On Pseudotsuga taxifolia. taxifolia Swain — Cornicles normal (fig. 97), being quite conspicuous. Third antennal segment with two-four clearly defined sensoria (fig. 101). On Picea glehni. glehnus Essig A SYNOPSIS OF THE APHIDIDAE 47 45. Lachnus ferrisi Swain Figures 89, 91 Davidson, Jour. Econ. Ent., vol. 2, p. 299, 1909. Lachnus abietis Fitch (list). Davidson, Jour. Econ. Ent., vol. 3, p. 374, 1910. LacUnus dbietis Fitch (list). Essig, Pom. Jour. Ent., vol. 4, p. 773, 1912. Ladhnus abietis Fitch (list). Swain, Trans. Am. Ent. Soc., vol. 44, p. 9, 1918. Records. — Abies concolor, Stanford University (Davidson) ; Pinus sp., Stan- ford University (Swain). This large lachnid, recently described by the author, has been found only in the vicinity of Stanford University, in 1909 and 1910 by Davidson on lowland fir, and in 1915 by Ferris on some young pine trees. Since then it has not been observed. 46. Lachnus glehmis Essig Figures 96, 97 Essig, Pom. Jour. Ent. Zool., vol. 7, pp. 180-187, 1915 (orig. desc.). Eecord. — Picea glehni, Sacramento (Essig). Essig described this species from specimens taken on a Japanese spruce in Capitol Park, Sacramento, in 1912. At the time it was so abundant that control measures were deemed necessary. The author \ has had access to the type specimens in Essig 's collection. 47. Lachnus occidentalis Davidson Davidson, Jour. Econ. Ent., vol. 2, p. 300, 1909 (orig. dese. apterae). Davidson, Jour. Econ. Ent., vol. 3, p. 374, 1910 (list). Essig, Pom. Jour. Ent., vol. 4, p. 773, 1912 (list). Wilson, Can. Ent., vol. 44, p. 193, 1912 (desc. all forms). Records. — Abies grandis, Stanford University (Davidson, Morrison, Ferris and the author) ; Abies concolor, Corvallis, Oregon (Wilson). This species is practically always present on a lowland fir tree in the cactus garden of the Stanford University grounds. Wilson has found it in the vicinity of Corvallis, Oregon, on white fir. Davidson states that it is heavily preyed upon by the larvae of Syrphus arciuvtus and Syrphus opinator. 48 MISCELLANEOUS STUDIES 48. Lachnus oregonensis Wilson Wilson, Trans. Am. Ent. Soc., vol. 12, p. 103, 1915 (orig. desc.). Eecord. — Pinus contorta, Oregon and California (Wilson). There has been no published record of this species from California. Wilson wrote the author some time ago that he had taken it in this state, although he gave no definite locality. The author has never seen specimens. • 49. Lachnus pini-radiatae Davidson Figure 95 Davidson, Jour. Econ. Ent., vol. 2, p. 299, 1909 (orig. desc.). Davidson, Jour. Econ. Ent., vol. 3, p. 374, 1910 (list). Davidson, Pom. Jour. Ent., vol. 3, p. 398, 1911 (list). Essig, Pom. Jour. Ent,, vol. 4, p. 773, 1912 (list). Essig, Pom. Jour. Ent., vol. 4, p. 785, 1912 (descriptive note). Becords. — Pinus radiata, Stanford University (Davidson), August, 1914, April, 1915 (author), March, 1916 (K. B. Brown); Pinus ponderosa, Bowman, Placer County, November, 1911 (H. H. Bowman), Berkeley, March, 1915 (Geo. Shinji) ; Pinus sabiniana, Penryn, Placer County (Davidson). This is a fairly small, slender-bodied, long-legged lachnid found infesting the needles of various pines in the San Francisco Bay region and in the Sacramento Valley. They are easily recognized on the needles by the whitish mass of flocculence which covers their bodies. 50. Lachnus ponderosa Williams Figure 104 Williams, Univ. Neb. Studies, vol. 10, p. 106, 1910 (orig. desc.). Davidson, Jour. Econ. Ent., vol. 7, p. 127, 1914 (list). Eecord. — Pinus ponderosa jeffreyi, Tallac, Eldorado County (Davidson). Davidson's is the only report of this species in California. The identification of his specimens was verified by Davis. One specimen the author saw was quite small, being much smaller than the others taken by Davidson. 51. Lachnus pseudotsugae Wilson Figures 92, 98 Wilson, Can. Ent., vol. 44, pp. 159, 302, 1912 (orig. desc.). Eecord. — Pseudotsuga taxi folia; Oregon, California (Wilson). A SYNOPSIS OF THE APE I DI DAE 49 Wilson wrote the author some time ago that he had taken this species in California, although he gave no definite locality or collec- tion record. The author has had the opportunity to study cotype specimens. 52. Lachnus sabinianus n.sp. Eecord. — Pinus sabinian-a, San Francisco (Compere). In March, 1915, Harold Compere of the California State Insectary found a small infestation of a species of Lachnus on Digger Pine in the Golden Gate Park, San Francisco. Since this one collection, the species has not again been observed. Being unable to identify the species with any described in America, a description is herewith appended, the species being named after its host plant, Pinus sabin- iana. All the specimens, including the types are in the collections of E. 0. Essig and of the University of California, Berkeley. The specimens were all mounted in Canadian balsam before color notes were taken, so those in the following description are only approxi- mately correct. Alate viviparous female. — Rich chestnut-amber to dark brown. Antennal segments I and II, amber; III, yellowish with tips darker; IV, V, and VI, dark yellow to dusky. Prothorax, chestnut-brown. Thoracic lobes very dark brown to black. Beak, pale with tips dusky. Cornicles, black. Cauda and anal plate with distal margins black. Femora, chestnut-brown with base amber; tibiae, brown with amber ring near the base; tarsi, amber. Wing veins, grayffi stigma, dusky Measurements : Body 4.2 mm. long and 1.7 mm. wide at thorax. Antennae reach to base of abdomen, without secondary sensoria. I, 0.10 mm. ; II, 0.09 mm. ; III, 0.50 mm. ; IV, 0.25 mm. ; V, 0.19 mm. ; VI, 0.08 mm. ; total, 1.21 mm. Beak reaches to the base of the cor- nicles. Cornicles medium sized and of the usual Lachnus shape, being Apterous viviparous female. — Chestnut-brown in color with black dorsal spots on abdomen. Antennal segments I and II, dark; III, dusky yellow with tip dark; IV, V, and VI slightly darker. Beak reaches to the base of the cornicles. Coxae, black ; femora, black with basal one-fifth paler; tibiae, black with pale ring near base; tarsi, black. Cornicles, black and conspicuous. They measure 5.2 mm. in length and 3.3 mm. in width. 50 MISCELLANEOUS STUDIES 53. Lachnus taxifolia Swain Figures 99-103 Swain, Trans. Am. Ent. Soc., vol. 44, p. 11, 1918. Eecords. — Pseudotsuga taxifolia, Sacramento (Essig), Berkeley and San Fran- cisco (Shinji). This is a fairly qommon species found in colonies on the branches and trunks of Douglas fir in the San Francisco Bay and Sacramento Valley. It is interesting particularly because of the atrophied cor- nicles. 54. Lachnus tujafilinus (Del Guercio) Figures 93, 105 Del Guercio, Eedia, vol. 5, p. 287, 1909. Laclmeilla (orig. desc.). Essig, Pom. Jour. Ent., vol. 3, p. 541, 1911. Lachnus juniperi DeGeer (desc.). Essig, Pom. Jour. Ent., vol. 4, p. 773, 1912. Lachnus juniperi DeGeer (list). Davidson, Jour. Econ. Ent., vol. 7, p. 127, 1914 (list). Eecords. — Thuya occidentalis, Claremont, Santa Paula (Essig); Palo Alto, Walnut Creek (Davidson); Stanford University, March, 1912 (Morrison); San Diego, March, 1916; Riverside, October, 1916, March, 1917. This oddly marked Lachnus is more or less common throughout California wherever arborvitae is cultivated. The apterous females are the most common, and are easily recognized by the odd markings on the dorsum of the abdomen (see Essig 's illustrations). Occasion- ally the alate females are found, Davidson finding some in April, Morrison and the author in March. The author has observed the larvae of Coccinella calif ornica feeding on them in Riverside. 55. Lachnus vanduzei n.sp. Figure 88 Records. — Picea sp., Berkeley, September, 1914 (Essig, E. P., Van Duzee). In September, 1914, E. P. Van Duzee collected a few specimens of a large Lachnus on a species of spruce in Strawberry Canyon, near Berkeley. Later in the same month Essig found specimens on the same tree. The following fall the author hunted for the species, A SYNOPSIS OF THE APHIDIDAE 51 but was unable to find any specimens, the tree on which it was first found having been cut down. In the following description the color notes are not absolutely accurate, as they were taken from material mounted in balsam. This species is named after its first collector, Mr. E. P. Van Duzee, of the University of California. Type speci- mens are in the collection of the University of California. Alate viviparous female. — The alate viviparous females are of a dark muddy color, as near as can be judged from the mounted specimens. The antennae are : I and II, dusky ; III and IV, pale with apical half dusky ; V, pale with the apex or apical third dusky ; VI, pale with the apex and spur dusky. The measurements of the segments are : I, 0.09 mm.; II, 0.07 mm.; Ill, 0.5 mm.; IV, 0.26 mm.; V, 0.27 mm.; VI, 0.16 mm. The sensoria are located as follows : III, 10-12 ; IV, 2-3 ; V, 2-3 ; VI, 1. They are large and circular, and quite evenly distributed in a line on each segment. The beak reaches to the base of the cauda. The coxae are black, the femora amber on the basal half and black on the apical, the tibiae are black with an amber ring near the base, the tarsi are black. The first joint of the hind tarsus is not one-third the length of the sedond, the first measuring 0.08 mm., and the second 0.26 mm. The wings are quite large, with a very distinct stigma. The costal vein is grayish-brown, the subcostal brown. The stigma is long and brown, the stigmal vein being pale brown and slightly curved throughout its entire length. The first and second discoidals are distinct and pale brown, the second dis- coidal being slightly curved near the tip. The third discoidal is indis- tinct and twice-branched, the angles of the branches being very acute. Apterous viviparous female. — Prevailing color, amber-brown, with the abdomen mottled gray, brown, and black. The head is brown with anterior margin amber. The antennae are colored as follows: I, amber; II, amber; III, amber with tip dusky; IV, amber with tip dusky ; V, amber with apical two-thirds dusky ; VI, dusky. The beak reaches to the base of the cauda. The femora are brown with the bases amber, the tibiae and tarsi brown. The first joint of the hind tarsus is scarcely more than one-third the length of the second. In four tarsi measured, the relative lengths of the joints were: 0.07 to 0.23 mm. ; 0.08 to 0.23 mm. ; 0.08 to 0.28 mm. ; and 0.07 to 0.25 mm. The cornicles are conspicuous and dark, the cauda well rounded and dark on its posterior edge. The lengths of the antennal segments are : I, 0.1 mm. ; II, 0.1 mm. ; III, 0.56 to 0.57 mm. ; IV, 0.21 to 0.23 mm. ; V, 0.22 to 0.28 mm. ; VI, 0.15 to 0.16 mm. 52 MISCELLANEOUS STUDIES Group Aphidina Wilson Wilson, Ann. Ent. Soc. Am., vol. 3, p. 314, 1910. This group as considered by Wilson consists of three tribes: Trichosiphini, Macrosiphini, and Aphidini. The first of these con- tains two genera found only in the Asiatic islands, so it will not be considered in this p'aper. This group contains quite closely related genera, and in many cases it is quite hard to distinguish between them. Following is a brief extract from Wilson's paper (cited above) : In studying closely related genera the development of the external characters may be placed in five divisions: (1) the antennae and spur; (2) the antennal tubercles; (3) the development of the nectaries [cornicles]; (4) the development of the cauda; (5) the development of the wing venation. In a group of insects as pliable as the present one, any one or two of these characters may be either under- or over-developed and it is necessary to place the genera according to the greatest development. Of all the characters which show this variation the wings show what may be true of all these characters. The two tribes have been separated from one another on the character of the antennal tubercles, as Wilson says in the same paper : The division is made between species with distinct antennal tubercles and those having none or at the most indistinct tubercles. However, should a certain species have distinct antennal tubercles with the other characters [of the Macro- siphini] wanting, then it would have to go into the next tribe [Aphidini]. The keys to the tribes and genera below have been formulated by the author, following, however, those of Wilson, Van der Goot, and Mordwilko. 1. Antennal tubercles well formed. Antennae usually as long as or longer than the body. Apterae often with sensoria on the third antennal segment. Body never with lateral tubercles on the seventh abdominal segment. Cor- nicles variable but usually about one-fourth the length of the body or longer Tribe Macrosiphini — Antennal tubercles absent or more or less indistinct. Antennae seldom longer than the body. Apterae seldom with sensoria on the third antennal seg- ment. Body with lateral tubercles on at least the seventh abdominal seg- ment Tribe Aphidini Tribe Macrosiphini Wilson Wilson, Ann. Ent. Soc. Am., vol. 3, p. 314, 1910. To a large extent the author has followed Wilson in the placing of the genera, but in a few cases he has not. This is noticeable in Toxoptera, which is considered by Wilson as belonging to this tribe, A SYNOPSIS OF TEE APHIDIDAE 53 while the author feels that it is better associated with the Aphidini, inasmuch as the antennal tubercles are very small and more or less indistinct and as the antennae are scarcely as long as the body. Van der Goot's genus, Myzaphis, has been accepted for the two species, Myzus rosarum (Walker) and Aphis abietina Walker, and is included with the Aphidini. The species Aphis nymphaeae Linn., which Wil- son uses as the type of Rhopalosiphum, has been taken from this genus and placed in Siphocoryne, chiefly because of the apparent absence of antennal tubercles and of the presence of distinct tubercles on the seventh abdominal segment. Therefore Aphis persicae Sulzer takes the place as type of the genus Rhopalosiphum. KEY TO CALIFORNIA GENERA 1. Cornicles cylindrical, or at most but very slightly swollen on one side (figs. 122, 152 ) 4 — Cornicles distinctly swollen toward apex, or clavate (figs. 109, 113, 119) 2 2. Antennal tubercles very large and tapering but not gibbous on the inner side; the bases of the antennae being more or less approximate (fig. 107). Nectarosiphon Schouteden — Antennal tubercles distinct, but not large and tapering as above, being more or less toothed or gibbous on the inner side; the bases of the antennae not approximate (figs. 108, 111) 3 3. Antennal tubercles short and wedge-shaped, the outer side not evident (fig. 108). Cauda ensiform and of medium size. Antennae at most but slightly longer than the body Rhopalosiphum Koch — Antennal tubercles short, but not wedge-shaped (fig. 111). Antennae con- siderable longer than the body. Cauda very large and long. Amphorophora Buckton 4. Antennal tubercles large and as long on the outer as on the inner side (fig. 106) 5 — Antennal tubercles with outer side shorter than inner, or not evident (figs. 112, 115, 116) 7 5. Cornicles tapering, longer than cauda which is ensiform (fig. 152). "Wing venation regular, with third discoidal twice-branched. Macrosiphum Passerini — Cornicles and cauda variable. Wing venation irregular and very striking with veins either wanting or combined, and shaded 6 6. Antennal tubercles with short upper inner angle. Cauda shorter than cornicles and tapering. Stigmal and third diseoidal veins meet in a broad dark band, giving the wing the appearance of having a closed triangular cell (fig. 110) Idiopterus Davis — Antennal tubercles with small rounded tubercle at the upper inner angle. Cornicles slightly constricted in the middle and at the tip. Wing venation variable, but usually the stigmal and third discoidal veins are partly joined and form a distinct, closed, four-sided cell Pentalonia Coquerel 7. Antennal tubercles and first antennal segment with a strong tooth on the inner side of each (figs. 115, 116). Cauda short and tapering (fig. 118). Cornicles cylindrical and tapering slightly with tip outcurved (fig. 117). Rhorodon Passerini 54 MISCELLANEOUS STUDIES — Antennal tubercles with a distinct but not prominent blunt projection forming the inner angle (fig. 112), but the prominent teeth as above are lacking. Cauda short, tapering, and usually triangular (fig. 121). Cornicles as above, being cylindrical, with a slight tapering from base to apex, and often slightly outcurved at tip (fig. 122) Myzus Passerini 21*. Genus Amphorophora Buckton Buckton, Monog. Brit. Aphides, 1876. Type A. ampullata n.sp. KEY TO CALIFORNIAN SPECIES9 Cornicles pale, or at most slightly dusky, swollen and vasiform (fig. 113). VI spur longer than III, the latter with 35-45 sensoria riibi (Kalt.) Cornicles black, greatly dilated in apical one-half (fig. 161). VI spur shorter than III, latter with 13-17 sensoria latysiphon Davidson 56. Amphorophora latysiphon Davidson Figure 161 Davidson, Jour. Econ. Ent., vol. 5, p. 408, 1912 (orig. desc.). Records. — Vinca major, San Jose (Davidson) ; Courtland, Contra Costa County (Davidson) ; Stanford University, 1912 (Morrison, Essig). Convolvulus arvensis, San Jose (Davidson). Solarium tuberosum, Walnut Creek, Contra Costa County, 1915 (Davidson). This species has been found sparingly in the San Francisco Bay region on periwinkle, morning-glory, and potato tubers, although it has never seemed to be common. The author has not collected it, his only specimens being some taken by Essig on periwinkle near Stan- ford University. The odd shape of the cornicles is a distinguishing character. 57. Amphorophora rubi Kalt. Figures 111, 113, 162 Kaltenbach, Monog. d. Pflanzenlause, p. 23, 1843. Aphis (orig. desc.). Davidson, Jour. Econ. Ent., vol. 5, p. 411, 1912 (list). Shinji, Can. Ent., vol. 49, p. 52, 1917 (list). Records. — Hubus parviflorus; San Jose (Davidson) : Eubus spp., Walnut Creek, 1915 (Davidson); Berkeley (Shinji). This species has been taken a few times on thimble-berry in the San Francisco Bay region. Davidson writes that he has also found it on blackberry and loganberry in the vicinity of Walnut Creek, »G. O. Shinji (Can. Ent., vol. 49, p. 51, 1917) described an aphid from Ciculta virosa var. calif ornica in Berkeley, which he called Amphorophora cicutae n.sp. The author has never seen specimens, so does not feel that he can recognize this as a good species. Of some half dozen new (?) species described by Shinji the author has found none, on examining specimens, that are good species, hence he cannot recognize this one at present. A SYNOPSIS OF THE APHIDIDAE 55 Contra Costa County. The author has recently received specimens from Gillette of an alate viviparous female and apterous oviparous females taken in the vicinity of Fort Collins, Colorado. Inasmuch as the descriptions of this species are inadequate and not readily acces- sible it has been thought best to give here brief descriptions of the different forms. As no color notes were received with the specimens they must necessarily be omitted. Alate viviparous female (from Fort Collins, Colorado). — Antennae half as long again as the body, dusky, and placed on small but distinct tubercles. From the mounted material it appears as if III were dusky, IV, pale with extreme tip dusky ; V, pale with apical one-third dusky; and VI dusky. VI spur is the longest segment, followed by III, IV, V, VI base, I, and II. The usual primary and accessory sensoria are present on VI base, and the primary sensorium on V. Secondary sensoria are present only on III. These are small, circular, irregular-sized, and irregularly placed along the whole length of the segment. The number (35 to 40) is such as to make the segment appear tuberculate. The beak is quite large and long, reaching to or slightly beyond the third coxae. The thorax is dusky. The wings fairly large, and normal. The second branch of the third discoidal vein arises nearer to the base of the first branch than to the apex of the wing. Normally the measurements are as follows : From the base of the second branch of the third discoidal to the tip of the wing is about 0.8 mm., from the base of the first branch to the base of the second 0.4 mm., from the apex of the first branch to the apex of the second 0.29 mm. In one case the base of the second branch was 1.02 mm. from the apex of the wing, and but 0.034 mm. from the base of the second, while the apices of the two branches were but 0.187 mm. apart. The legs are long, femora pale with apical one-fourth dusky, tibiae and tarsi dusky. The abdomen is pale with some slight dorsal dark markings, these being indistinct in the mounted specimens. The cornicles are fairly long, clavate on the apical one-half or two-thirds, dusky throughout, and with the extreme tip reticulated. In length they are somewhat shorter than III, but longer than IV. The cauda is pale, short, and triangular, being about equal in length to the hind tarsi. Measurements : body length, 1.785 mm. ; antennae total, 2.788 mm. ; III, 0.68 mm. ; IV, 0.51 mm. ; V, 0.408 to 0.425 mm. ; VI, base, 0.12 mm.; VI, spur, 0.867 to 0.884 mm.; cornicles, 0.578 to 0.646 mm.; cauda, 0.102 mm.; hind tarsi, 0.102 mm.; wing length, 3.128 mm.; width, 1.292 mm. ; expansion, 6.8 mm. 56 MISCELLANEOUS STUDIES Apterous oviparous female (Fort Collins, Colorado). — Pale throughout, with many small hairs scattered over the body. Most of these hairs are simple, but some especially on the front of the head and on the bases of the antennae, are capitate. Antennae slightly longer than the body, pale, with VI and the apices of the other seg- ments dusky. \l spur and III are subequal or either one may be slightly longer than the other. These are followed by IV, V, VI base, I, and II. The usual primary and accessory sensoria are present on VI base, and the primary sensorium of V. Secondary sensoria are present only on III, and number about nine or ten. These are small, circular, but varying in size, and are arranged in a more or less even line along the basal one-half to two-thirds of the segment. Beak pale, with tip dusky, quite large and long, reaching to or beyond the third coxae. Thorax and legs normal, except the hind tibiae which are quite long, and furnished with a large number of sensoria. These sensoria cover practically the whole joint. Cornicle very long and large, curved outward, pale, with apex dusky, and with distinct reticulations at the extreme tip. They are markedly larger than in the alate viviparous females, being considerably longer than the third antennal segment, and in some cases even half as long again. The cauda is small, pale, and triangular, although somewhat larger in the viviparous female. Measurements : bodj* length, 2.04 mm. ; width of thorax, 0.595 mm. ; antennae total, 2.446 mm. ; III, 0.646 to 0.697 mm. ; IV, 0.442 to 0.459 mm. ; V, 0.356 to 0.374 mm. ; VI, base, 0.136 mm. ; VI, spur, 0.663 mm. ; cornicles, 0.918 to 0.952 mm. ; cauda, 0.187 mm. ; hind tarsi, 0.136 mm. 22. Genus Idiopterus Davis Davis, Ann. Ent. Soc. Am., vol. 2, p. 198, 1909. Type, I. neprelepidis n.sp. 58. Idiopterus nephrelepidis Davis Figure 110 Davis, Ann. Ent. Soe. Am., vol. 2, p. 198, 1909 (orig. desc.). Davidson, Jour. Econ. Ent., vol. 3, p. 376, 1910 (list). Essig, Pom. Jour. Ent, vol. 3, p. 538, 1911 (list). Records. — Nephrolepis exaltata, Santa Paula (Essig), Palo Alto, April, 1915, San Diego, March to May, 1916; Riverside, February, 1917: Cyrtonium fulcotum, Berkeley, March, 1915 (Essig); ferns (unidentified species of house ferns), Stan- ford University (Davidson, Morrison); Viola sp., Claremont (Essig). This small black aphid is often found in houses and nurseries, and occasionally out of doors, on the fronds of various kinds of house A SYNOPSIS OF THE APHIDIDAE 57 ferns, particularly the Boston fern. Essig has also found it on violets in the vicinity of Pomona College. The alate females have the wings beautifully marked with black and white. 23. Genus Macrosiphum Passerini Passerini, Gli Afidi, 1860. Type Aphis rosae Linn. KEY TO CALIFORNIA SPECIES Alate viviparous females 1. Cornicles slightly clavate on one side, somewhat as in Bhopalosiphum. tulipae (Monell) — Cornicles not clavate 2 2. Ill as long as V and VI (base and spur) sonchella (Monell) — Ill not as long comparatively 3 3. Ill pale, IV, V, and VI dusky jasminum (Clarke) — Not so; if IV, V, and VI are dusky then III is also, except perhaps the base; or if III is pale throughout then at least the greater part of IV and V are also pale 4 4. VI (base and spur) shorter than III, but V and VI together are longer than III baccharadis (Clarke) — VI (base and spur) not shorter than III 5 5. Secondary sensoria on III, IV, and V. Cornicles not reticulated. heucherae (Oestlund) — No secondary sensoria on V 6 6. Secondary sensoria on both III and IV. Cornicles with tips at least reticulated (fig. 152 ) 7 — No secondary sensoria on IV 10 7. Cornicles and cauda subequal in length, the former being more or less bottle- shaped sanborni Gillette — Cornicles longer than cauda 8 8. Cauda light green. Secondary sensoria only occasionally present on IV and then very small and indistinct rosae (Linn.) — Cauda dark (brown or black). Seven or more distinct secondary sensoria on IV 9 9. Body with capitate setae, especially on head and antennae. artemisiae (Fonsc.) — Body without capitate setae. Abdomen with dark dorsal markings. lactucae (Kalt.) 10. Cornicles with at least tips reticulated (fig. 132) 14 — Cornicles with no reticulations (fig. 156) 11 11. Body with fan-shaped setae artemisicola (Williams) — Body without fan-shaped setae 12 12. Distal two-thirds of cornicles black orthocarpus (Dvdn.) — Only tip of cornicles black 13 13. Cornicles long and slender. About 18 secondary sensoria in a row on III (fig. 130) pisi (Kalt.) — Cornicles shorter and heavier. About 25 to 30 sensoria scattered irregularly along III (fig. 157) dirhodum (Walker) 14. Cornicles with more than apical one-half reticulate (fig. 149). ludovicianae (Oestlund) — Cornicles with less than apical one-half reticulated (fig. 128) 15 58 MISCELLANEOUS STUDIES 15. Cornicles dusky for practically their entire length ............................................ 20 — Cornicles with less than apical one-half dusky .................................................. 16 16. Cornicles considerably longer than III, with apical portion curved outward. About a dozen, medium-sized sensoria in a straight line along basal two- thirds of III (fig. 131) .................................................. californicum (Clarke) — Cornicles not considerably longer than III ........................................................ 17 17. Cornicles and VI spur subequal, the former fairly long, slightly curved outward and Rightly swollen before the tip (fig. 128) ........ Stanley! Wilson — Cornicles considerably shorter than VI spur, and not swollen before the tip 18 18. Secondary sensoria in a fairly straight line on III. Body not pulverulent 19 — Body covered with a slight pulverulence. Ill with about 30 fairly large- sized sensoria, more or less scattered along the entire length (fig. 143). albifrons Essig 19. Cornicles about half the length of VI spur and considerably shorter than III, the latter with about 20 to 30 secondary sensoria .................. pteridis Wilson — Cornicles about two-thirds as long as VI spur and slightly shorter than III, the latter with about 15 sensoria (fig. 133) ................ cucurbitae (Thomas) 20. Ground or basal color of abdomen green ............................................................ 21 — Ground or basal color of abdomen red, brown, or black .................................... 24 21. Cornicles green, sometimes dusky at apex ........................ solanifolii (Ashmead) — Cornicles black ........................................................................................................ 22 22. Ill with a small number (9-15) of secondary sensoria on basal one-half (fig. 135) ; longer than VI spur ........................................ granarium (Kirbyj — Ill with some 30 or more sensoria scattered along its entire length (figs. 151, 159); subequal to or shorter than VI spur ......... . ........................................ 23 23. Cornicles and III subequal. Tibiae with apices only dusky ........ rosae (Linn.) — Cornicles longer than III. Tibiae dusky throughout. rudbeckiae (Fitch) n.var. madia 24. Cauda pale ................................................................................................................ 25 — Cauda dusky ............................................................................................................ 27 25. Ill and VI spur subequal ................... : ................................................ rosae (Linn.) — Ill shorter than VI spur .............................................. . ....................................... 26 26. Cauda about one-half as long as cornicles, the latter shorter than IV. chrysanthemi (Oestlund) — Cauda slightly more than one-half as long as cornicles, the latter equal to or longer than IV ...................................................................... rudbeckiae (Fitch) 27. Ill and VI spur subequal ...................................................................................... 28 — Ill longer than VI spur .................................................................. taraxici (Kalt.) 28. Body yellowish-brown in color; legs same except tarsi and tips of tibiae and femora which are dusky to black ...................................... valerianae (Clarke) — Body dark reddish-brown to black in color; legs dusky throughout. ambrosiae (Thomas) Apterous viviparous 1. Cornicles clavate on one side, somewhat as in Elwpalosiplium. tulipae (Monell) — Cornicles not so, being cylindrical or subcylindrical .......................................... 2 10 Only the species of which there are specimens available to the author, or of which there are adequate descriptions, are included in this key. The species rep- resented in the author's collection are marked with an asterisk (*). The author recognizes the great difficulty in separating the apterae of various species, par- ticularly in this genus, and offers this key merely as a slight aid toward the recog- nition of the better known species. A SYNOPSIS OF THE APHIDIDAE 59 2. Ill without or at most with only a few secondary sensoria (0-12) 11 — Ill with several (over 12) secondary sensoria scattered along the greater part of its length 3 3. Cornicles short and tapering, being somewhat bottle-shaped and not distinctly longer than the cauda sanborni Gillette* — Cornicles normal, being cylindrical and considerably longer than the cauda 4 4. Ill and IV with secondary sensoria heucherae (Oestlund) — IV without secondary sensoria 5 5. General body color dark, being red, wine, brown or black 6 — • General color lighter, usually being a shade of green 8 6. Cauda black. Legs black, except the bases of the femora taraxici (Kalt.) — Cauda pale. Legs with at least the bases of the femora and tibiae not black 7 7. Legs green, except tarsi and apices of femora and tibiae. Cauda not more than half the length of the cornicles. Not more than ten to twelve sensoria on the basal one-third of III rosae (Linn.)* — Legs black, except bases of femora and tibiae, which are light brown. Cauda more than half the length of the cornicles. A considerable number of sensoria scattered over more than the basal one-half of III. rudbeckiae (Fitch)* 8. Cornicles subequal to or shorter than III. Body covered with a whitish pul- verulence 9 — Cornicles distinctly longer than III. Body without whitish pulverulence .... 10 9. Cornicles, except tip, and cauda green; the former subequal in length to III and about twice as long as cauda albifrons Essig* — Cornicles black, cauda yellow or light brown; the former considerably shorter than III and not twice as long as cauda ludovicianae (Oestlund)* 10. Cauda quite broad and blunt at end. Cornicles with not more than apical one- sixth reticulated rosae (Linn.) * — Cauda slender and pointed. Cornicles with apical one-fourth reticulated. rudbeckiae (Fitch) n.var. madia* 11. Body covered with capitate or fan-shaped setae 12 — Body without specialized setae 14 12. Setae with fan-shaped tips and thickly covering the body. Cornicles slender and imbricated for their entire length artemisicola (Williams)* — Setae capitate and only sparsely covering body 13 13. Cornicles fairly stout, with tips reticulated, and about twice as long as cauda. artemisiae (Fonsc.) — Cornicles slender, with no reticulations, and considerably more than twice the length of the cauda pteridis Wilson 14. Cornicles with tips at least reticulated 16 — Cornicles with no reticulations 15 15. Cornicles very long and slender. Antennae considerably longer than body. pisi (Kalt.)* — Cornicles shorter and heavier. Antennae at most but slightly longer than body dirhodum (Walker)* 16. Cornicles for the most part dusky or black 17 — Cornicles mostly pale or green 19 17. Cornicles and III subequal. Body not pulverulent 18 — Cornicles considerably shorter than III. Body more or less pulverulent. ludovicianae (Oestlund)* 60 MISCELLANEOUS STUDIES 18. Ill with but two or four sensoria near base; longer than VI spur. gr anarium ( Kirby ) * — Ill with six or so sensoria on basal one-half ; shorter than or equal to VI spur rosae (Linn.)* 19. Cornicles longer than III 20 — Cornicles at most subequal to III 21 20. Antennae pale, except VI and the apices of III to V. Cornicles slightly swollen near distal end Stanley! Wilson* — Antennae dusky, except III, basal part of IV, and perhaps the extreme base of V. Cornicles long, slender, and out-curved californicum (Clarke)* 21. Cauda broad, and blunt, with the sides almost parallel and about half as long as cornicles lactucae (Kalt.) * — Cauda slender-pointed, and more than half as long as cauda 22 22. VI spur and III subequal solanifolii (Ashmead)* — VI spur considerably longer than III cucurbitae (Thomas)* 59. Macrosiphum albifrons Essig Figures 143, 144 Davidson, Jour. Econ. Ent., vol. 2, p. 304, 1909. Macrosiphum sp. (list). Essig, Pom. Jour. Ent., vol. 3, p. 543, 1911 (orig. desc.). Records. — Lupinus sp., Santa Paula (Essig) ; Stanford University (Davidson) ; Jasper Ridge, Coast Range Mountains, Santa Clara County, April, 1912 (V. G. Stevens) ; Berkeley, April, 1915 (Geo. Shinji) ; Mount Hood, Oregon, August, 1916 (E. A. McGregor). This large, flocculent aphid is found occasionally infesting various lupines throughout the Pacific Coast, from southern California north, well into Oregon. The author has specimens from Berkeley and Oregon, although he has never collected it himself. 60. Macrosiphum ambrosiae (Thomas) ? Thomas, 111. Lab. Nat. Hist., Bull. 2, p. 4, 1878. Siphonoplwra (orig. desc.). Sanborn, Kans. Univ. Sci., Bull. 3, p. 74, 1904 (desc.). Beoords. — Helianthus annuus; Orange (T. D. A. Cockerell) ; San Diego, April, 1916. In 1915 the author received a few specimens of this species from T. D. A. Cockerell from Orange, and in 1916 he collected it once on sunflower in Exposition Park, San Diego. At first it was thought to be M. sonchi (Linn.), and was so reported by Cockerell. Since then it was identified by J. J. Davis as probably M. ambrosiae (Thomas). A SYNOPSIS OF THE APHIDIDAE 61 61. Macrosiphum artemisiae (Fonsc.) Figures 142, 145 Boyer de Fonscolmbe, Ann. Ent. Soe. France, vol. 10, p. 162, 1841. Aphis (orig. desc.). Essig, Pom. Jour. Ent., vol. 3, p. 546, 1911. Macrosiphum frigidae (Oest.) (desc.). Davidson, Jour. Econ. Ent., vol. 3, p. 133, 1914. Macrosiphum frigidae (Oest.) (list). Wilson, Trans. Amer, Ent. Soc., vol. 41, p. 97, 1915 (desc.). Records. — Artemisia calif ornica ; Santa Paula (Essig) ; Walnut Creek, Contra Costa County (Davidson). Occasionally this species is found infesting the tender shoots of the common California sage brush. It is characterized by the presence of capitate hairs scattered sparsely over the body, particularly of the apterous female. The synonomy above is after Wilson, who lists M. frigidae (Oestlund) as a synonym of artemisiae (Fonsc.). 62. Macrosiphum artemisicola (Williams) Figures 146, 147 Williams, Univ. Neb. Studies, vol. 10, p. 73, 1910. Siphonophora (orig. desc.). Wilson, Trans. Am. Ent. Soe., vol. 41, p. 96, 1915 (desc.). Records. — Artemisia tridentata, A. vulgaris; Oregon (California) (Wilson). Although there is no published record of the presence of this species in California it is included here on Wilson's authority. He stated to the author that he had found it in California, although he failed to give any date or locality record. This is characterized by the fan-shaped setae which thickly cover the body of the apterae, and which are present on the ventral side of the abdomen of the alates. The author has specimens taken by R. W. Haegele in the summer of 1915 on Artemisia sp. near Canton, Montana. 63. Macrosiphum baccharadis (Clarke) Clarke, Can. Ent., vol. 35, p. 254, 1903. Nectarophora (orig. desc.). Record. — Baccharis sp., Berkeley (Clarke). This species is one of those described by Clarke, but since then unknown. It is possible that it is M. rudbeckiae (Fitch), which is so common on Baccharis throughout California. 62 . MISCELLANEOUS STUDIES 64. Macrosiphum calif ornicum (Clarke) Figures 131, 132 Clarke, Can. Ent., vol. 35, p. 254, 1903. Nectarophora (orig. desc. apterae). Davidson, Jour. Econ. Ent., vol. 2, p. 304, 1909 (list). Davidson, Jour. Econ. Ent., vol. 3, p. 380, 1910 (list). Davidson, Pom. Jour. Ent., vol. 3, p. 398, 1911 (list). Essig, Pom. Jour. Ent., vol. 3, p. 548, 1911. M. laevigatae, n.sp. (orig. desc.). Eecords. — Salix sp. ; Newcastle, Placer County (Clarke); Stanford University and Penryn, Placer County (Davidson) ; Stanford University, November, 1914 (Morrison), May, 1915; Berkeley, April, 1915 (Shinji) ; August, 1915, Salix laevigata; Santa Paula (Essig) ; Riverside, May, 1917. Clarke described the apterous females of a species of Nectarophora (Macrosiphum) from specimens taken on willow in Placer County. Because of the extremely long cornicles it is possible to identify this with specimens taken since throughout the San Francisco Bay region on various species of willows. Essig 's M. laevigatae from Santa Paula is the same species, having been compared by the author with specimens from Stanford University and Berkeley. Morrison has taken the males and oviparous females of this species in the vicinity of Stanford University in November, 1914. The author has reared specimens of Aphidins polygonaphis Fitch, and Praon simulans Prov. from this species taken in Berkeley. 65. Macrosiphum chrysanthemi (Oest.) Oestlund, 14th Rep. Geol. Surv. Minn., vol. 22, 1886. Siphonophora (orig. desc.). Davidson, Jour. Econ. Ent., vol. 5, p. 411, 1912 (list). .Record.— Undetermined species of Compositae; Courtland (Davidson). This is a doubtful species taken by Davidson at one time from an undetermined composite near Courtland. The author is entirely unacquainted with the species. 66. Macrosiphum cucurbitae (Thos.) Figures 133, 134 Thomas, 8th Ann. Rep. Illinois St. Ent., p. 66, 1879. Siphonophora (orig. desc.). Becord. — Cucur'bita sp., Hayward, Alameda County, July, 1915 (Roy E. Camp- bell) ; Los Angeles, May, 1917. A SYNOPSIS OF THE APHIDIDAE 63 In July, 1915, Roy E. Campbell of the Bureau of Entomology, sent the author specimens of a Macrosiphum sp. from squash in Hay- ward. In 1917 the author found the same species abundantly on squash in Los Angeles. These the author identified as being specimens of M. cucurbitae (Thomas). Later J. J. Davis verified the deter- mination. This is a new record for California. As the available descriptions of this species are quite inadequate, the author gives herewith a few descriptive notes taken from these specimens.. Alate viviparous female. — Antennae longer than the body, placed on distinct frontal tubercles, dusky except I, II, and extreme base of III. The spur of VI is the longest segment, followed by III, which is about four-fifths as long. IV and V are subequal, and almost as long as III. The usual primary and accessory sensoria are present on V and VI. Secondary sensoria are present on III (fig. 133), being small, circular, numbering about 14 to 15, and arranged in a fairly even row along the whole length of the segment. Beak pale with dusky tip, reaching to the second coxae. Thorax and abdomen green, the thoracic lobes not conspicuously darkened. Cornicles (fig. 134) green with apical one-third dusky, equal to or slightly longer than III, imbricated with tip reticulated. Cauda large, pale, vasiform, slightly more than half the length of the cornicles, reaching to their apices. Wings and legs normal. Measurements : Body length, 2.3 mm. ; antennae total, 3.25 to 3.35 mm. ; III, 0.685 to 0.714 mm. ; IV, 0.629 to 0.646 mm. ; V, 0.603 to 0.612 mm. ; VI, base, 0.136 to 0.153 mm. ; VI, spur, 0.935 to 0.696 mm. ; cornicles, 0.714 to 0.731 mm. ; cauda, 0.408 mm. 67. Macrosiphum dirhodum (Walker) Figures 156, 157 Walker, Ann. Nat. Hist., (2), vol. 3, p. 43, 1848. Aphis (orig. desc.). Theobald, Jour. Econ. Biol., vol. 8, p. 128, 1913 (desc.). Patch, Maine Agr. Exp. Sta., Bull. 233, p. 268, 1914 (note). Gillette, Jour. Econ. Ent., vol. 8, p. 103, 1915 (note). Record. — Eose, Santa Ysabel (3000 feet altitude), San Diego County, May, 1916; Eiverside, April, 1917. The author found this species sparingly on rose near Santa Ysabel, San Diego County, in May, 1916, and again in April, 1917, in River- side. According to Gillette, this species passes the winter on rose, and the summer on various grains and grasses, as M. rosa-e (Linn.) 64 MISCELLANEOUS STUDIES may do. These are the only records of it in California. The author has compared it with specimens taken by R. W. Doane in 1915 on grain in Utah. 68. Macrosiphum granarium (Kirby) Figures 135, 148 Kirby, Linn. Soc. Trans., vol. 4, p. 238, Aphis (orig. desc.). Davidson, Jour. Econ. Ent., vol. 5, p. 411, 1912 (list). Theobald, Jour. Econ. Biol., vol. 8, p. 58, 1913 (desc.). Davidson, Mon. Bull., Cal. Comm. Hort., vol. 6, p. 65, 1917 (note). Records. — Graminaceae (various species) ; San Jose (Davidson) ; Stanford University, January to May, 1915 ; Berkeley, March, 1915 : Typha latifolia (Davidson). This is a more or less common species of Macrosiphum on various grains and grasses in the San Francisco Bay region during the winter and spring. In late spring and early summer, as the grasses begin to dry out, it leaves them for the cat-tail rush or California tule (Davidson, 1917). In the late fall or early winter it returns to the grains and grasses, where it passes the winter in the viviparous forms. 69. Macrosiphum heucherae (Thomas) Thomas, 8th Ann. Kep. Illinois St. Ent., p. 66, 1879. Siphonophora (orig. desc. ) . Davidson, Jour. Econ. Ent., vol. 8, p. 427, 1915 (desc.). Record. — Heuchera ihartwegi, Kedwood Canyon, Contra Costa County (David- son). In the latter part of May, 1914, Davidson found all the forms, including the apterous and alate viviparous females, the apterous oviparous females, the alate males, and eggs on the flower stalks of alum root in Contra Costa County. Since his description no record has been made concerning the species. The author is unacquainted with it, having never seen specimens. 70. Macrosiphum jasmini (Clarke) Clarke, Can. Ent., vol. 35, p. 252, 1903. Ncctarophora (orig. desc.). Record. — Jessamine, Berkeley (Clarke). Since Clarke's description of the apterous viviparous females of this species it has never been found. Its identity is, therefore, un- known to the author. A SYNOPSIS OF THE APHIDIDAE 65 71. Macrosiphum lactucae (Kalt.) Kaltenbach, Monog. d. Pflanzenlause, p. 199, 1857. Nectarophora (orig. desc.). Sanderson, Can. Ent., vol. 33, p. 69, 1901. Nectarophora (desc.). Essig, Univ. Calif. Publ., Entom., vol. 1, p. 328, 1917 (list). Record. — Cicorium intybus, Kutherford^ Napa County, 1916 (Essig). This species has been taken only by Essig on chicory in Napa County during June, 1916. As its determination is doubtful the author gives herewith a brief description of the alate female. Body pale to green, with the following parts more or less dusky : head, antennae, prothorax, thoracic lobes, apex of beak, tarsi, apical one-fifth to one-fourth tibiae, apical one-half femora, cornicles, anal plate, marginal spots on the abdominal segments, submarginal spots of the second and third abdominal segments, dorsal bands on the fourth and fifth, and the dorsum of the remaining abdominal seg- ments. Eyes red. The antennal tubercles are prominent and project rectangularly inward. A prominent frontal tubercle is present on the apex. The antennae are about half as long again as the body. The usual primary and accessory sensoria are present. On III there are from thirty-five to forty-five circular secondary sensoria; on IV from five to fifteen secondary sensoria. These two segments appear tuberculate. The beak reaches beyond the second coxae. The cornicles are longer than the cauda, and subequal in length to the fourth antennal segment. They are subcylindrical and fairly stout. The cauda is long and ensi- form, reaching to the tip of the cornicles. The wings and venation are normal. Measurements (of three specimens) : Body length, 1.836 to 1.955 mm. ; width of thorax, 0.765 to 0.833 mm. ; antennae, total, 2.805 to 2.992 mm. ; III, 0.680 to 0.697 mm. ; IV, 0.441 to 0.527 mm. ; V, 0.391 to 0.425 mm. ; VI, base 0.085 to 0.119 mm. ; VI, spur 0.952 to 1.105 mm. ; cornicles, 0.441 to 0.493 mm. ; cauda, 0.238 to 0.272 mm. ; hind tarsi, 0.136 to 0.153 mm. ; wing, length, 3.145 to 3.315 mm. ; width, 0.952 to 1.139 mm. ; expansion, 7.36 to 7.87 mm. 72. Macrosiphum ludovicianae (Oestund) Figures 136, 148 Oestlund, Minn. Geol. Nat. Hist. Surv., vol. 14, p. 23, 1886. Siphonophora (orig. desc.). Davidson, Jour. Econ. Ent., vol. 7, p. 136, 1914 (list). Wilson, Trans. Am. Ent. Soc., vol. 12, p. 98, 1015 (desc.). 66 MISCELLANEOUS STUDIES Records. — Artemisia heterophylla ; Walnut Creek, Contra Costa County (David- son), Berkeley, 1915 (Shinji); Artemisia dracunculoides, Convolvulus sp., Stachys bullata, Berkeley, 1915 (Shinji). This species is quite common in the San Francisco Bay region on various species of sagebrush. George Shinji has taken it also on hedge- nettle and bindweed in Berkeley. It is distinguished from other sage- infesting species of Macrosiphum by the fact that the body of the apterous females is covered with pointed setae as opposed to the fan- shaped setae of M. artemisicola (Williams), and the capitate setae of M. artemisiae (Fonsc.). 73. Macrosiphum orthoearpus Davidson Davidson, Jour. Econ. Ent., vol. 2, p. 304, 1909 (orig. dese.). Davidson, Jour. Econ. Ent., vol. 3, p. 380, 1910 (list). Record. — Orthoearpus purpurascens ; Stanford University (Davidson). Since Davidson found the specimens on owl-clover from which he described this species, it has not again been taken. 74. Macrosiphum pisi (Kalt.) Figures 130, 150 Kaltenbach, Monog. d. Pflanzenlause, p. 23, 1843. Aphis (orig. desc.). Davidson, Jour. Econ. Ent., vol. 2, p. 304, 1909 (list). Davidson, Jour. Econ. Ent., vol. 3, p. 380, 1910 (list). Essig, Pom. Jour. Ent., vol. 2, p. 336, 1910. Nectarophora (desc.). Branigan, Mon. Bull. Cal. Comm. Hort., vol. 4, p. 285, 1915. M. destruc- tor (Johnson) (list). Davis, U. S. Dept. Agr., Bull. 276, p. 11, 1915 (list). Records. — Pisum sativum; Claremont, Santa Ana, and Ventura (Essig) ; Ala- meda County (Brannigan) ; El Cajon, San Diego County, May, 1916: Lathyrus odoratus; Stanford University (Davidson, Morrison); San Diego, October, 1916: Viola sp. ; Claremont, Santa Ana, Ventura (Essig); Medicago sp. ; Holtville, Imperial County (V. L. Wildermuth) : Psorales macrostachya; Santa Paula (Essig). The pea aphis is quite common throughout the state, especially on garden and sweet peas. It has been taken a few times on other plants, such as alfalfa, violets, and leather-root, but it is uncommon. This species is readily distinguished by its bright, shining green color, large size, and long, slender, imbricated, but non-reticulated cornicles. A SYNOPSIS OF THE APHIDIDAE 67 75. Macrosiphum pteridis Wilson Figures 317, 318 Wilson, Trans. Am. Ent. Soc., vol. 41, p. 101, 1915 (orig. desc.). Records. — Pteris aquilina; Walnut Creek, Contra Costa County, 1915 (David- son). This species has been found by Davidson on the fronds of common brake in the San Francisco Bay region. Wilson reported it as present throughout southern and western Oregon. There are a few specimens of the alate females in the author 's collection, received from Davidson. 76. Macrosiphum rosae (Linn.) Figures 106, 151, 152 Linnaeus, Syst. Nat. vol. 4, p. 73, 1735. Aphis (orig. desc.). Clarke, Can. Ent., vol. 35, p. 254, 1903. Nectarophora (list). Davidson, Jour. Econ. Ent., vol. 2, p. 304, 1909 (list). Davidson, Jour. Econ. Ent., vol. 3, p. 380, 1910 (list). Davidson, Pom. Jour. Ent., vol. 3, p. 399, 1911 (list). Essig, Pom. Jour. Ent., vol. 5, p. 550, 1911 (desc.). Games, Mon. Bull. Cal. Comm. Hort., vol. 1, p. 398, 1912 (list). Records. — Eose; through California from Humboldt County south to San Diego County (Clarke, Davidson, Morrison, Essig, Ferris, Shinji, the author). This is the common pink and green aphid of roses, known the world over. The apterae are found most abundantly in the late win- ter and early spring on the buds and stems of rose. As the alates are matured they fly away, supposedly either to other rose bushes or to various grains and grasses. This past spring (1917) it has been very abundant in the vicinity of Eiverside, but the previous spring (1916) in San Diego it was rare. There the most abundant rose aphis was Myzaphis rosarum (Walker). 77. Macrosiphum rudbeckiae (Fitch) Fitch, Cat. Homop. N. Y., p. 66, 1851. Aphis (orig. desc.). Essig, Pom. Jour. Ent., vol. 3, p. 400, 1911. Aphis (dese.)." Davidson, Jour. Econ. Ent., vol. 7, p. 137, 1914 (list). Records. — Ambrosia psilostachya; Santa Paula (Essig) ; Baccharis viminalis; Santa Paula (Essig), Riverside, September, 1916; Dipsacus fullonum; San Jose (Davidson): Helianthus annuus; Eiverside, September, 1916; Salix sp. ; Chrysan- themum; Arlington, Eiverside County, September, 1916; undetermined species of Compositae; Bedwood Canyon, Contra Costa County, July, 1914 (E. W. Haegele). 11 In the drawings accompanying this description by Essig the following mis- takes are noticeable: the third discoidal vein of the forewings is twice-branched instead of once-branched, and the third antenal segment of the apterous female bears several secondary sensoria instead of none, as figured. 68 MISCELLANEOUS STUDIES This reddish-colored Macrosiphum is distributed abundantly through the San Francisco Bay region and southern California on various Compositae. In one case the author found it doing consider- able damage to chrysanthemums by stunting and distorting the buds. Once he found it infesting the tender leaves and stalks of willow. The author reared specimens of Diarctns rapae Curt, from an infesta- tion of this species taken on willow. 77a. Macrosiphum rudbeckiae (Fitch) var. madia n.var. Figures 153, 154 In September, 1915, the author found a species of Macrosiphum infesting the heads of tarweed (Madia sativa) on the campus of the University of California, Berkeley. Specimens of Praon simulans Prao. were reared from this collection. Mounted specimens are almost identical with M. rudbeckiae (Fitch), but in life they differ in the coloration. Because of this it has been thought best to describe it herewith as a color variety of M. rudbeckiae, naming the variety. madia, after its host plant. Host: Madia sativa. Date: September 12, 1915. Locality: Berkeley, California. Collection number: AFS 70-15. Alate viviparous female. — Prevailing color: dark-green, slightly pruinose. Head brownish (fuscous), about as long as broad, with distinct antennal tubercles. Antennae black, except I and II and the base of III, which are concolorous with the head. The spur is slightly longer than III ; IV is next in length, followed by V, VI, and I, which are subequal, and II, which is the shortest segment. The spur is about six times as long as the base of VI. The usual primary sensoria are present on V and VI, and the usual accessory sensoria on VI. IV is without sensoria, III has 25-35 irregularly arranged, various-sized secondary sensoria placed along the whole length of the segment (fig. 154). The thorax is fuscous; the prothorax with rather distinct lateral tubercles. The beak is slightly dusky with the apical one-third black, reaching to the second coxae. The abdomen is greenish with a slight pulverulence, making it appear pruinose. The cornicles are long, slightly tapering, black except the basal one-third, which is concolorous with the abdomen, apical one-fifth reticulate (fig. 153). The cauda is long and pointed, pale (slightly reddish?), about one- half as long as the cornicles. The legs are black except the basal half of the femora and the coxae, which are greenish. The wings and venation are normal. A SYNOPSIS OF THE APHIDIDAE 69 Measurements: Body length (exclusive of cauda), 2.11 mm. ; width of thorax, 0.91 mm. Antennae : total, 2.07 mm. ; I, 0.12 mm. ; II, 0.09 mm. ; III, 0.76 mm. ; IV, 0.55 mm. ; V, 0.47 mm. ; VI, 0.12 mm. ; spur, 0.78 mm. ; cornicles, 0.91 mm. ; cauda, 0.45 mm. ; beak, 0.89 mm. ; hind tarsus, 0.14 mm. Wing: length, 3.6 mm.; width, 1.25 mm.; expansion, 8.11 mm. 78. Macrosiphum sanborni Gillette Figures 141, 155 Sanborn, Kans. Univ., Sci. Bull. 3, p. 73, 1904. Macrosiphum chrysanthemi (desc. ala. vivi.). Gillette, Can. Ent., vol. 11, p. 65, 1908 (orig. desc. apt. vivi.). Records. — Chrysanthemum; Stanford University, May, 1915; Riverside, March, 1917. Twice has the author found this species: once a small infestation in the greenhouse of Stanford University, and once abundantly out of doors in Riverside. It is an interesting species in that it does not fit well into any known genus. Except for the cornicles it fits Macro- siphum and has been so considered. The cornicles are, however, short, being scarcely longer than the cauda, and are somewhat bottle-shaped, being considerably smaller at the apex than at the base. 79. Macrosiphum solanifolii (Ashmead) Figures 137-140, 159-160 Ashmead, Can. Ent., vol. 12, p. 91, 1881. Siphonophora (orig. desc.). Clarke, Can. Ent., vol. 35, p. 252, 1903. Nectarophora citrifolii (Ashmead) (list). Davidson, Jour. Econ. Ent., vol. 31, p. 380, 1910. Macrosiphum citrifolii (Ashmead) (list). Essig, Pom. Jour. Ent., vol. 3, p. 592, 1911. Macrosiphum citrifolii (Ash- mead) (desc.). Davidson, Jour. Econ. Ent., vol. 5, p. 411, 1912 (list). Patch, Maine Agr. Exp. Sta., Bull. 242, 1915 (desc.). Records. — Citrus sp. ; Azusa, Los Angeles County (Clarke); Lindsey, Tulare County (Clarke) ; Santa Paula (Essig) ; Disporum Tnookeri; Berkeley, May, 1915 (Shinji) : Solatium nigrum; Stanford University, October, 1916 (Ferris) : Fuchsia sp. ; Berkeley, July, 1915: Sonohus asper and S. oleraoeus; Stanford University, February, 1915: apple; Stanford University, May, 1915; El Cajon, San Diego County, July, 1916: Atriplex sp. ; Berkeley, September, 1915: Oxalis corniculata, Eiverside, February, 1917: Deinandra fasciculata, Eiverside, February, 1917: Erodium moschatum; Pasadena, April, 1917 (E. E. Campbell); Eiverside, April, 1917. 70 MISCELLANEOUS STUDIES This "pink and green aphid of potato" is distributed throughout California on a large variety of plants. It is recognizable by the long reticulated cornicles and black antennae. When the author first exam- ined specimens of Macrosiphum citrifolii (Ashmead) in Essig's collec- tion he was struck with its resemblance to this species. In fact, after considerable study he could not find any constant differences. This was in 1915 in Berkeley. This past spring (1917) he had the opportunity in Riverside of making some transfer tests with specimens from oxalis. Migrants were placed under muslin bags on sucker growth of orange. It was observed that these settled there readily and produced young, demonstrating that the citrus species is the same as the other. On the strength of this Macrosiphum citrifolii (Ashmead) is listed as a synonym of this species. 80. Macrosiphum sonchella (Monell) ? Monell, U. S. Geol. Geog. Surv., Bull. 5, p. 21, 1879. Siphonophora (orig. desc.). Clarke, Can. Ent., vol. 35, p. 252, 1903. Nectarophora (list). Davidson, Jour. Econ. Ent., vol. 2, p. 304, 1909 (list). Davidson, Jour. Econ. Ent., vol. 2, p. 380, 1910 (list). Records. — Sonchus sp. ; Berkeley, Newcastle, and Palo Alto (Clarke); Stan- ford University (Davidson). According to Morrison the species listed as this by Davidson is not Macrosiphum sonchella (Monell), although he cannot say what it is. Consequently Clarke probably referred to the same species as did Davidson. As the author has never seen specimens he can make no statement as to its identity, so lists it as it has been heretofore. 81. Macrosiphum Stanley! Wilson Figures 128, 158 Wilson, Proc. Ent. Soc. Brit. Columbia, January, 1915 (orig. desc.). Eecord. — Sambiuxis callicarpa californica; Berkeley, June, 1915. From the early part of June, 1915, until the middle of August, this species was very abundant on an elderberry tree in the Botanical Gardens of the University of California. By the latter part of August all specimens had disappeared. Since then the author has never seen the species. J. J. Davis kindly identified these specimens. A SYNOPSIS OF THE APHIDIDAE 71 82. Macrosiphum taraxici (Kalt.) Kaltenbach, Monog. d. Pflanzenlause, p. 30, 1743. Aphis (orig. desc.). Theobald, Jour. Econ. Biol., vol. 7, p. 77, 1913 (desc.). Record. — Taraxacum officinale; California (Wilson). H. F. Wilson stated to the author that he had taken this species on dandelion (Taraxacum officinale} in California, although he gave no date or locality record. 83. Macrosiphum tulipae (Monell) Monell, U. S. Geol. Geog. Surv., Bull. 5, p. 19, 1879. Siphonophora (orig. desc.). Davidson, Jour. Econ. Ent., vol. 3, p. 380, 1910 (list). Records. — Tulipa sp. ; Stanford University (Davidson); Liriodendron sp. ; Berkeley, 1915 (Essig, Shinji). This species is not known to the author. It has been found on tulips and on the tulip trees in the San Francisco Bay region by Davidson, Essig, and Shinji. 84. Macrosiphum valerianae (Clarke) Clarke, Can. Ent., vol. 35, p. 253, 1903. Nectarophora (orig. desc.). Record. — Valeriana offlcinialis; Berkeley (Clarke). In 1903 Clarke described this species from specimens taken on heliotrope in Berkeley. Since then it has not again been found. 24. Genus Myzus Passerini Passerini, Gli Afidi, 1860. Type Aphis ribes Linnaeus. This genus is very closely related to Rhopalosiphum Koch, the principal difference being in the shape of the cornicles. However, some species fall easily into one or the other genus, depending entirely upon what form one has. In this respect Rhopalosiphum persicae (Sulz.) is particularly noticeable, the spring migrants having the clavate cornicles of Rhopalosiphum, the fall migrants having the cylindrical cornicles of Myzus. The author has followed Van der Goot in taking out of this genus M. rosarum (Walker) and placing it in the genus Myzaphis v.d.G. The antennal tubercles are lacking, thus placing the species in the Aphidini instead of the Macrosiphini. There are at present ten species of Myzus known to occur in Califor- nia. Following is a key to them: 72 MISCELLANEOUS STUDIES KEY TO THE CALIFORNIA SPECIES Alate viviparous females 1. Secondary sensoria present on III only 5 - Secondary sensoria present on other segments as well as on III 2 2. Secondary sensoria on III, IV, and V 3 - Secondary sensoria on III and IV, none on V fragaefolii Cockerell 3. Cornicles dusky for entire length cynosbati (Oestlund) — Cornicles mostly pale 4 4. Thoracic lobes distinctly darker than general body color, being black or dark brown aquilegia Essig — Thoracic lobes at most only slightly darker than body, being a pale brown. braggli Gillette 5. Body black throughout cerasi (Fabricius) — Body not black throughout 6 6. Cornicles pale except at extreme tip 7 — Cornicles with more than tip dusky 8 7. VI spur longer than III, the latter with but 9 to 12 sensoria. varians Davidson — VI spur at most equal to III, the latter with 18 to 26 sensoria. lycopersici (Clarke) 8. Cornicles longer than either IV or V 10 — Cornicles not longer than either IV or V 9 9. VI spur longer than II circumflexum (Buckton; — VI spur shorter than III rlbifolii Davidson 10. Ill with 15 to 25 sensoria (fig. 178) rhamni (Fonsc.) - Ill with but 9 to 12 sensoria varians Davidson Apterous viviparous female 1. Body covered with capitate hairs 2 — Body not covered with capitate hairs except on head and antennae 5 2. Secondary sensoria on III 3 — No secondary sensoria on III 4 3. Cornicles dusky ribifolii Davidson — Cornicles pale except tip aquilegiae Essig 4. Cornicles almost twice as long as III. Body fairly large sized. braggii Gillette — Cornicles but slightly longer than III. Body small sized. fragaefolii Cockerell 5. Secondary sensoria on III 6 — No secondary sensoria on III 7 6. VI spur longer than III. Several sensoria scattered along the whole length of III cynosbati (Oestlund ) — VI spur at most equal to III. Only a few (1-3) sensoria at base of III. lycopersici (Clarke) 7. Ill longer than cornicles. Dorsum of abdomen with dusky markings, shaped somewhat as a horseshoe circumflexum (Buckton) — Ill at most equal to cornicles. Abdomen not marked as above 8 8. Body black throughout cerasi (Fabricius) — Body not black throughout 9 9. VI spur almost twice as long as III varians Davidson — VI spur but slightly longer than III rhamni (Fonsc.) A SYNOPSIS OF THE APH1DIDAE 73 85. Myzus aquilegiae Essig Shinji, Can. Ent., vol. 40, p. 49, 1917. Myzus sp. (list). Essig, Univ. Calif. Publ Entom., vol. 1, p. 314, 1917 (orig. desc.). Eecords. — Aquilegia truncata; Berkeley, 1916 (Essig) : A. vulgare, Inverness, Marin County (Shinji). This species was recently described by Essig from specimens found on columbine on the campus of the University of California, Berkeley. The author has had access to cotype specimens, although he has never collected it himself. 86. Myzus braggii Gillette Figure 176 Gillette, Can. Ent., vol. 11, p. 17, 1908 (orig. desc.). Davidson, Jour. Econ. Ent., vol. 5, p. 409, 1912. Phorodon carduinum (Walker) (list). Eecords. — Cynara scolymus; Courtland, Oakland, and San Jose (Davidson) ; Riverside, January and February, 1917. The author found this species during the early spring of 1917 infesting the leaves of artichoke in Riverside. The determination of specimens was verified by C. P. Gillette. Davidson reported Phorodon carduinum (Walker) from artichoke in the San Francisco Bay region. His specimens were determined by J. Monell, but P. Van der Goot was doubtful as to its identity. Davidson himself has decided that the species is Myzus braggii Gillette. There is no doubt but that the species on artichoke in California is M. braggii Gillette, but whether or not this is the same as P. carduinum (Walker) is uncertain. 87. Myzus cerasi (Fabricius) Figures 112, 121, 122, 179, 307 Fabricius, Syst. Nat., p. 734. Aphis (orig. desc.). Clarke, Can. Ent., vol. 35, p. 252, 1903 (list). Gillette, Jour. Econ. Ent., vol. 1, p. 362, 1908 (desc.). Newman, Mon. Bull. Calif. Comm. Hort, vol. 4, p. 446, 1915 (list). Shinji, Can. Ent., vol. 49, p. 49, 1917 (list). Eecords. — Prunus cerasi; Susanville, Lassen County (Newman) ; Berkeley, 1914, 1915, and 1916 (Essig, Shinji) ; Eiverside, 1914 (Sharp) ; Fresno, June, 1915: Prunus domestica; Berkeley (Clarke). 74 MISCELLANEOUS STUDIES The black cherry aphis is found occasionally throughout Califor- nia, but seldom in large enough numbers to be injurious. It infests the terminal leaves of cherry, and sometimes other species of Prunus, causing them to curl to a certain extent. Eggs are laid in the late fall and early winter in the crevices of the bark and near the bases of the buds. These hatch the following spring about the time the buds are opening. The first few generations consist entirely of apterous females. In the early summer the alate females appear, and con- tinue to do so in each succeding generation until fall. In fact, after the first of July, or thereabouts, the majority of the lice produced are alate until the sexes appear in the fall. The first alate females taken by the author were on June 7, 1915. However, on April 25, 1916, Essig found a few alate females in Berkeley. In August, 1914, the apterae were also found in Berkeley. Van der Goot makes this species out of the genus Myzus, using it as the type of his genus Myzmdes. The author is inclined to follow him inasmuch as this is quite different from other members of this genus, approaching Aphis in its robust form and separated from that only by the length of the cornicles and presence of antenna! tubercles. However, it has so long been considered as a species of Myzus that it is best to leave it so. It is not a good policy usually to form a new genus for one species, especially when it has for so long been considered as a member of another genus. 88. Myzus circumflexus (Buckton) Figure 175 Buckton, Monog. Brit. Aphides, vol. 1, p. 130, 1875. Siphonopliora (orig. desc.). Gillette, Can. Ent., vol. 40, p. 19, 1908. M. vincae, n.sp. (desc.). Davidson, Jour. Econ. Ent., vol. 3, p. 380, 1910. M. vincae Gill. (list). Shinji, Can. Ent., vol. 49, p. 49, 1917 (list). Record. — Vinca major; Stanford University (Davidson, Morrison), Berkeley, 1915 (Shinji), Los Angeles, March, 1917; Aesculus californicus, Alopecurus pratensis, Asparagus, spp., Ceanothus sp., Cerastium viscosum, Cheiranthus chieri, Cyrtonium falcatum, Digitalis purpurea, Fuchsia sp., Gladiolus sp., Plantago sp., Senecio mikanioides, Sisymbrium sp., Solanum spp., Stachys bullata, Tropaeolum sp., Symphoricarpus racemosus; Berkeley, 1915, 1916 (Essig, Shinji) : Viola tri- color; Stanford University, March, 1915; Berkeley, 1915 (Essig, Shinji): Rioliardia africana; Pomona, 1909 (Essig); Stanford University, March, 1915; Berkeley, March, 1915 (Essig) ; San Diego, May, 1916; Los Angeles, March, 1917. This very common aphid is found in the spring on a large variety of host plants throughout California. At times it may become so X A SYNOPSIS OF THE APHIDIDAE 75 abundant as to cause some considerable damage to its host. On March 4, 1917, the author observed it on periwinkle in Los Angeles in such numbers as to stunt the flowers and to cause all the plants to appear black and sticky. The apterae of this species are readily recognized by the black horseshoe-shaped marking on the dorsum of the abdomen. 89. Myzus cynosbati (Oestlund) Oestlund, Minn. Geol. and Nat. Hist. Surv., Bull. 4, p. 81, 1887. Nectaro- phora (orig. desc.). Davidson, Jour. Econ. Ent., vol. 10, p. 294, 1917 (note). Shinji, Can. Ent., vol. 49, p. 49, 1917. M. ribis (Linn.) (list). Records. — Eibes vulgar e; Walnut Creek (Davidson) ; Eibes glutinosum, E. menziesii; Berkeley, April, 1915 (Shinji). This species has been taken but a few times in the San Francisco Bay region; once on cultivated red currant in company with Aphis neomcxicana pacifica, once on wild flowering currant, and once on wild canyon gooseberry. Furthermore, only the sexapura (migrants) and sexuales have been taken. Davidson writes that this is true cynosbati of Oestlund and not the species described by Davis (Ann. Ent. Soc. Am., vol. 2, p. 38, 1909), as Macrosiphum cynosbati (Oest.), which is not that species but some other. Shinji listed M. ribis (Linn.), but his specimens prove to be the sexuales of this species. 90. Myzus fragaefolii Cockerell Figure 177 Cockerell, Can. Ent., vol. 33, p. 101, 1901 (orig. desc.). Davidson, Jour. Econ. Ent., vol. 7, p. X35, 1914 (desc. sexuales). Records. — Fragaria chiloensis; Walnut Creek, Contra Costa County (David- son); Berkeley, March to September, 1915; Palo Alto, April, 1915; Ontario, April, 1917; Buena Park, Orange County, May, 1917 (E. K. Bishop); Santa Barbara, May, 1917; Eialto, San Bernardino County, May, 1917 (A. B. Snow): F. californicus; Pine Hills, San Diego County, June, 1916. On the under side of the leaves of native and cultivated straw- berries this small yellowish aphid is often found, both in the San Francisco Bay region and in southern California. Seldom does it become abundant, although several records of its abundance were received from various parts of the south during the spring of 1917. Several growers have thought it bad enough to spray for it. During the late winter (January and February) the sexuales appear and the eggs are laid. These hatch in a short time, and during the rest of the year the alate and apterous viviparae are found. 76 MISCELLANEOUS STUDIES 91. Myzus lycopersici (Clarke) Clarke, Can. Ent., vol. 35, p. 253, 1903. Nectaropliora (orig. desc.). Davis, Can. Ent., vol. 46, p. 123, 1914 (desc.). Eecord. — Lycopersicum esculentum ; Berkeley (Clarke). Only once has this species been found in California. Davis in 1914 described a species from tomato in Idaho, Montana, and Oregon which he believed to be this one. It may be, and it may not be so. That can never be decided for the types of -Clarke's species are all lost. 92. Myzus rhamni (Clarke) Figure 178 Clarke, Can Ent., vol. 35, p. 254, 1903. Nectaropliora (orig. desc.). Shinji, Can. Ent., vol. 49, p. 49, 1917. M. rhamni (Boyer) (list). Records. — Rhamnus calif ornicus; Berkeley (Clarke), Berkeley, March, 1915 (Shinji). In March, 1915, George Shinji took a species of Myzus from coffee- berry in Berkeley. This fits Clarke's description of Nectarophora rhamni, in so far as the description goes. The author considers it to be the same species as described by Clarke, inasmuch as it was collected in the same locality and on the same host plant. Wilson (Can. Ent., vol. 44, p. 156, 1912) describes a species from Rhamnus purshiana in Oregon as M. rhamni (Boyer), listing Clarke's species as a synonym. This is the same species as taken by Shinji in Berkeley, but it is doubtful if it is the species described by Boyer de Fonscolombe. Specimens in the author's collection from Rhamnus in Colorado are determined by Gillette and Bragg to be Aphis rhamni Fonsc. These are certainly different from the coast species, the former being an Aphis closely related to A. euonomii Fabr., the latter a Myzus. From this evidence the author cannot follow "Wilson in placing Nectarophora rhamni Clarke as a synonym of Aphis rhamni Fonsc., considering both as Myzus, but he considers them as distinct, Clarke's species being a Myzus, Fonscolombe 's an Aphis. 93. Myzus ribifolii Davidson Davidson, Jour. Econ. Ent., vol. 10, p. 294, 1917 (orig. desc.). Record. — Ribes glutinosum; Eedwood Canyon, Contra Costa County (David- son). A SYNOPSIS OF THE APHIDIDAE 77 Davidson recently described all forms of this species from speci- mens taken during March, April, and May, 1913, 1914, and 1915, on wild flowering currant in Redwood Canyon, Contra Costa County. The author is unacquainted with the species. 94. Myzus varians Davidson Davidson, Jour. Econ. Ent., vol. 5, p. 409, 1912 (orig. desc.). Record. — Clematis ligusticifolia ; San Jose (Davidson). Davidson found this species on the under side of the leaves of wild clematis, or Yerbade chivato, near San Jose, and later in Walnut Creek, Contra Costa County. The author is unacquainted with the species. 25. Genus Nectarosiphon Schouteden Schouteden, Aphidologische Notizen, Leipzig, 1901. Type Macrosiphum rubicola Oestlund, n.n. for Macrosiphum Oestlund, preoccupied. KEY TO CALIFORNIA SPECIES 1. Body quite large, being about 3 to 4 mm. in length. Wings with dusky spot near tip rubicola (Oestlund) — Body not so large, being only about 1.5 mm. long. Wings without dusky spot near tip morrisoni Swain 95. Nectarosiphon rubicola (Oestlund) Figures 107, 109, 123 Oestlund, Minn. Geol. Nat. Hist. Surv., vol. 14, p. 27, 1886. Macrosiphum (orig. desc.). Davidson, Jour. Econ. Ent., vol. 7, p. 136, 1914. Amphorophora (list). Eecords. — Hubus nutlcanus; Contra Costa County (Davidson) ; Berkeley (Essig, Shinji). This species is sometimes found infesting the tender leaves and shoots of thimbleberry in the San Francisco Bay region. The most distinctive character which readily separates it from Amphorophora rubi (Kalt.) is the presence of a dusky patch near the tip of the fore- wing. This was originally described by Oestlund as the type of his genus Macrosiphum. However, this name was preoccupied by Macro- siphum Passerini, so Schouteden proposed the name Nectarosiphon for this genus. Davidson listed this species as Amphorophora, and Morrison writes that he has never been able to satisfy himself why 78 MISCELLANEOUS STUDIES this is not Amphorophora instead of Nectar osiphon. There is con- siderable difference in the antennal tubercles of this species and species of Amphorophora, although otherwise they are quite similar. The author believes that slight as the difference is it should be recog- nized for it is through the shape and size of the antennal tubercles that the different genera of the Macrosiphini are recognized in a large part. In this species the tubercles are large and distinct and neither gibbous nor toothed on the inner side, and with the outer side quite evident, while in Amphorophora they are small and distinctly toothed on the inner side, with the outer side a mere line, or not at all evident. 96. Nectarosiphon morrisoni Swain Figures 124 to 127 Swain, Trans. Am. Ent. Soc., vol. 44, p. 8, 1918. Records. — Cupressus macrocarpa; San Francisco (Compere, Morrison), San Diego (Swain) : C. guadalupensis; San Diego (Swain). In Golden Gate Park, San Francisco, and in Exposition Park, San Diego, this species has been taken on cypress. The small, slender, long-legged apterae are found infesting the terminal leaves of the host. Occasionally an alate female is seen. In San Diego, the apterae were found in company with Cerosipha cupressi Swain. 26. Genus Pentalonia Coquerel Coquerel, Ann. Ent. Soe. France, vol. 7, p. 239, 1860. Type P. nigro- nervosa n.sp. 97. Pentalonia nigronervosa Coquerel Coquerel, Ann. Ent. Soe. France, vol. 7, p. 239, 1860 (orig. desc.). Wilson, Jour. Econ. Ent., vol. 2, p. 346, 1909 (desc.). Record. — Pelargonium sp. ; Stanford University (Morrison). The following note concerning this species is from Morrison: Pentalonia nigronervosa Coquerel. See Wilson, Jour. Econ. Ent., 1909. In the Davidson collection (belonging to Stanford University) there is a single glycerine jelly mount of this species. I have been able to see enough of it to be certain of its identity with that described by Wilson in the Journal (above). The record is from geranium, and Davidson once told me that he found it in alcohol in the laboratory [of Stanford University] at the time he began his study of the Aphididae. I believe the record should be published. A SYNOPSIS OF THE APHIDIDAE 79 27. Genus Phorodon Passerini Passerini, Gli Afidi, 1860. Type P. humuli Schr. No attempt has been made to formulate a key to the California species of this genus, owing to the fact that the author has specimens of but one species, and that the description of the other is quite inade- quate. Four species have been reported from this state, two of which prove to be species of other genera and one of which is very doubtful. Phorodon carduinum (Walker) as reported by Davidson, is Myzus braggi Gillette. Phorodon galeopsidis (Kaltenbach), also reported by Davidson, is Rhopalosiphum hippophoaes Koch. There is much diversity of opinion concerning the specific determination of these species and of Myzus elaeagni "Del Guercio. One might refer to Gil- lette 's paper on Rhopalosiphum hippophaaes Koch and Myzus braggii Gillette. Davis writes that he is not prepared to be quoted. Davidson lists P. galeopsidis and R. hippophoaes as synonyms. He states that his specimens listed as P. carduinum Walker were determined by Monell, but that Van der Goot is doubtful, while he himself believes them to be M. braggii Gillette. He has been followed in so listing them. This then leaves but two species reported from California. 98. Phorodon humuli (Schrank) Figures 115 to 118 Schrank, Fauna Boica, vol. 2, p. 110, 1801-02. Aphis (orig. desc.). Clarke, Can. Ent., vol. 35, p. 252, 1903 (list). Clarke, Calif. Agri. Exp. Sta., Bull. 160, 1904 (econ.). Parker, U. S. Dept. Agri., Bull. Ill, 1913 (econ.). Vosler, Mon. Bull., Cal. Comm. Hort., vol. 2, p. 668, 1913 (list). Records. — Humulus spp. ; Berkeley (Clarke); Placer County' (Vosler) ; Berke- ley, July to September, 1915: Prunus domestica; Berkeley, March to April, 1915 (Essig, Shinji) ; (Parker). This is the common hop plant louse found throughout the central part of the state. During the summer it is common on hops, but in the fall the sexupara migrate to plum, where the eggs are laid. These eggs hatch the following spring into stem mothers which feed on the opening buds of plum. During later generations, probably about the third or fourth, alate fundatrigeniae appear, which leave the plum and migrate to hop. Here the summer generations are produced until well into the fall. Parker states that the normal life cycle is as just stated, but that it is also possible, and it occasionally occurs, that this 80 MISCELLANEOUS STUDIES aphid may live the entire year upon hops, or on plum, generation after generation of parthenogenetic females being produced. 99. Phorodon scrophulariae Thomas Thomas, Ann. Eep. 111. St. Ent., vol. 8, p. 72, 1879 (orig. desc.). Clarke, Can. Ent., vol. 35, p. 252, 1903 (list). Eecord. — Scrophularia sp., Berkeley (Clarke). This is a doubtful species, reported by Clarke as present on Scrophularia in Berkeley, and by Dr. Thomas in 1879 on a species of plant which he thought to be Scrophularia in Illinois. Since Clarke's record it has never been found, although Morrison states that he has spent considerable time examining the common Scrophu- laria plants in the vicinity of Stanford University, but to no avail. The author attempted to find it many times in the vicinity of San Diego during 1916, and in the vicinity of Riverside in 1917, with no success. 28. Genus Rhopalosiphum Koch Koeh, Die Pflanzenlause, p. 23, 1854. Type Aphis persicae Sulz. This genus is very closely related to Myzus, and is distinguished only by the shape of the cornicles. This distinction is variable, how- ever, as in some species certain forms have the clavate cornicles of Rhopalosiphum while other forms have the cylindrical cornicles of Myzus. This is particularly true in the case of Rhopalosiphum persicae (Sulz.) and Myzus braggii Gillette. However, most aphidol- ogists separate these two genera, so the author feels that it is best to do so. KEY TO CALIFORNIA SPECIES Alate viviparous females 1. Ground color dark (olive-green, wine, brown, and so forth) 2 — Ground color light, usually green (this does not refer to the dark markings on head, thorax, or abdomen, but rather to the ground color of the abdomen) 4 2. Wing veins with smoky borders and tips (fig. 164). IV with a few small sensoria violae Pergande — Wing veins without smoky borders or tips, and IV without sensoria. rhois Monell 3. Antennae distinctly tuberculate, with sensoria on both III and IV (figs. 170, 279) 4 — Antennae not tuberculate, and IV without sensoria, or at most with but a few small ones (figs. 167, 168) 5 A SYNOPSIS OF TEE APEID1DAE 81 4. VI spur slightly longer than III (figs. 279, 281). Cornicles quite large and heavy (figs. 282, 284) lactucae (Kalt.) — VI spur about twice as long as III. Cornicles comparatively small and slender (fig. 165 ) hippophoaes Koch. 5. First discoidal vein with distinct, smoky border, second discoidal bordered slightly so (fig. 166) nervatum Gillette — First and second discoidal without smoky borders 6 6. Abdomen with dusky dorsal markings. Ill with a few (10-12) sensoria (fig. 168) persicae Sulz. — Abdomen without dusky dorsal markings. Ill with many (24-30) sensoria (fig. 167) corylinum Davidson Apterous viviparous females*2 1. Ground color dark (olive-green, wine, brown) 2 — Ground color light (green, and so forth) 3 2. Cornicles large and stout, longer than III rhois Monell — Cornicles smaller and more slender, shorter than III violae Pergande 3. Cornicles longer than III 4 — Cornicles shorter than III 5 4. VI spur considerably longer than III, and subequal to cornicles. nervatum Gillette — VI spur about equal to III, and distinctly shorter than cornicles. hippophoaes Koch. 5. Ill with secondary sensoria lactucae (Kalt.) — Ill with no secondary sensoria persicae (Sulz.) 100. Rhopalosiphum corylinum Davidson Figure 167 Davidson, Jour. Econ. Ent., vol. 7, p. 134, 1914 (orig. desc.). Records. — Corylus rostrata; Walnut Creek, Contra Costa County (Davidson) : Physocarpus capitatus; (Davidson). This species was originally described from specimens of alate viviparae and pupae taken on wild hazelnut near Walnut Creek. Davidson writes that he has found it quite common on nincbark in the San Francisco Bay region. The author has never taken the species, but has had access to cotype specimens in Essig's collection. 101. Rhopalosiphum hippophoaes Koch Figures 165, 170 Koch, Die Pflanzenlause, p. 28, 1854 (orig. desc.). Davidson, Jour. Econ. Ent., vol. 7, p. 136, 1914. Phorodon galeopsidis Kalt. (list). Gillette, Jour. Econ. Ent., vol. 8, p. 375, 1915 (synonomy). Record. — Polygonum sp.; San Jose (Davidson). 12 R. corylinum Dvdn. is omitted from this key as the apterous female was never described and specimens are not available to the author. 82 MISCELLANEOUS STUDIES Davidson reported this species as present on knotweed in the vicinity of San Jose, under the name P. galeopsidis Kalt. Later he followed Gillette in placing it as a synonym of R. hippophoaes Koch. The author has never collected it, but has had access to specimens from Davidson in San Jose, and Davis in Oak Park, Illinois. For a full discussion of the synonymy of this species see Gillette's paper listed above. 102. Rhopalosiphum lactucae (Kalt.) Figures 277 to 285 Kaltenbach, Monog. d. Pflanzenlause, p. 37, 1843. Aphis (orig. desc.). Davidson, Jour. Econ. Ent., vol. 3, p. 277, 1910 (list). Records. — Sonchus spp. ; Stanford University (Davidson); Stanford Univer- sity, May to July, 1915; Walnut Creek, May, 1915 (Davidson); Berkeley, July, 1915; Lemon Grove, San Diego County, January, 1916; Biverside, January to May, 1917; Los Angeles, April, 1917: Asclepias sp.; Corvallis, Oregon, November, 1913 (Moznette). This is a common species infesting the heads of sow thistle throughout the San Francisco Bay region and southern California. In November, 1913, G. F. Moznette took it on milkweed in Corvallis, Oregon. This collection consisted entirely of alate females, that may have been the sexupara. Inasmuch as the identity of this species is doubtful there is given below a brief description drawn from speci- mens of nine alates and eight apterae taken on Sonchus spp. at Stan- ford University in May, 1915, in Walnut Creek in May, 1915, in Berkeley in July, 1915, and in Lemon Grove in January, 1916, and on Asclepias sp. in Corvallis, Oregon, in November, 1913. This latter collection is by George F. Moznette of Corvallis. Alate viviparous female. — Prevailing color is apple green with the head dark green to black, the prothorax apple green, the thoracic lobes black. The abdomen is apple green with three pair of dusky marginal spots on segments one, two, and three, respectively, and with a larger dusky patch on the dorsum of segments four, five, and six, being between the cornicles. The cornicles and cauda are luteous with the extreme tip of the former dusky. The antennae are dusky throughout. The legs are luteous with the tarsi and tips of the femora and tibiae dusky. The head is about twice as broad as long, with a distinct frontal tubercle (fig. 278). The antennae are set on distinct tubercles and are between one and one-fourth to one and one-half times as long A SYNOPSIS OF THE APHIDIDAE 83 as the body. The relative lengths of the segments are as follows: the spur is the longest, being followed by III, which is subequal but never longer. IV is about one-half the length of the spur and slightly longer than V. II is slightly longer than VI, which is about equal to I. Sensoria are arranged as follows (figs. 279-281) : on V and VI are the usual primary and accessory sensoria; on V in addition to the primary sensoria, there are at times as many as seven small circular secondary sensoria, located about the middle of the segment. The number of these sensoria range from none to seven, two and three being the usual number ; on IV there are from six to twelve irregular secondary sensoria (fig. 280), placed irregularly along the whole length of the segment ; on III there are between thirty and forty irregularly placed and irregularly sized sensoria (fig. 279) scattered along the whole length of the segment. The usual number is from thirty-six to thirty-nine. The prothorax is without lateral tubercles. The beak is of medium length, reaching to slightly beyond the second coxae. The cornicles (fig. 282) are fairly large and clavate on one side. At the widest point they are slightly less than one-fifth the length. The tip is slightly wider than the base. They are about the same length as the fourth antennal segment, although in some cases they may be slightly longer, and in others slightly shorter, but in all cases longer than the fifth antennal segment. The cauda (fig. 283) is long and fairly large, not quite reaching to the tip of the cornicles, being about one-half as long as the cornicles and one-half as long again as the hind tarsi. The- wings and venation are normal, the forewings being about twice as long as the body. Measurements : Body length, 1.48 to 1.87 mm. ; width, 0.73 to 0.82 mm. ; antennae total, 2.35 to 2.51 mm. ; III, 0.544 to 0.697 mm. ; IV, 0.306 to 0.425 mm. ; V, 0.218 to 0.357 mm. ; VI, 0.085 to 0.119 mm. ; spur, 0.68 to 0.799 mm. ; cornicles, 0.323 to 0.459 mm. ; cauda, 0.187 to 0.255 mm. ; hind tarsi, 0.136 to 0.153 mm. ; wing length, 3.4 to 3.8 mm. ; wing width, 1.2 to 1.5 mm. ; wing expansion, 8.0 to 8.3 mm. The average measurements are as follows : body length, 1.74 mm. ; width, 0.768 mm. ; antennae total, 2.445 mm. ; III, 0.645 mm. ; IV, 0.382 mm. ; V, 0.328 mm. ; VI, 0.107 mm. ; spur, 0.753 mm. ; cornicles, 0.403 mm. ; cauda, 0.248 mm. ; hind tarsi, 0.139 mm. ; wing length, 3.6 mm. ; width, 1.32 mm. ; expansion, 8.1. Apterous viviparous female. — Prevailing color pale green with the head paler, being almost luteous or of a pale yellowish green color. The eyes are red. The antennae, except the apices of segments three 84 MISCELLANEOUS STUDIES to six inclusive, the legs, except the tarsi and tips of the tibiae, the cauda, and the cornicles, except the tip, are all luteous. Sensoria are as follows : on V and VI the usual primary sensoria, on VI the accessory sensoria, and on III (fig. 278), from nine to eleven small, circular irregularly placed secondary sensoria. IV is without sensoria. The antennae are considerably longer than the body, the spur and III being subequal and the longest segments. Sometimes the spur is slightly longer than III. V is about one-half as long as III or the spur, and about four-fifths as long as IV. I and VI are subequal, being about one-seventh as long as the spur. The cornicles (fig. 284), are clavate, quite large, usually being slightly more than one-fifth the length of the body and over three times the length of the hind tarsi. The cauda (fig. 285) is long, sickle-shaped, and a little more than one-half as long as the cornicles. Measurements : Body length, 1.7 to 2.18 mm. ; width of abdomen, 0.82 to 1.73 mm.; antennae total, 2.32 to 2.48 mm.; Ill, 0.646 to 0.714 mm. ; IV, 0.391 to 0.425 mm. ; V, 0.323 to 0.34 mm. ; VI, 0.102 mm. ; spur, 0.646 to 0.782 mm. ; cornicles, 0.459 to 0.493 mm. ; cauda, 0.238 to 0.272 mm.; hind tarsi, 0.136 to 0.153 mm. The average measurements are as follows : body length, 1.87 mm. ; width, 0.99 mm. ; antennae total, 2.39 mm. ; III, 0.674 mm. ; IV, 0.408 mm. ; V, 0.334 mm. ; VI, 0.102 mm. ; spur, 0.7099 mm. ; cornicles, 0.473 mm. ; cauda, 0.255 mm. ; hind tarsi, 0.1445 mm. 103. Rhopalosiphum nervatum Gillette Figures 166, 169, 171 Gillette, Can. Ent., vol. 40, p. 63, 1908 (orig. desc.). Davidson, Jour. Econ. Ent., vol. 3, p. 378, 1910. B. arbuti, n.sp. (desc.). Davidson, Jour. Econ. Ent., vol. 7, p. 134, 1914 (list). Records. — Arbutus menziesii; Stanford University, San Jose, Walnut Creek (Davidson); Sacramento (Essig) ; Stanford University, February to May, 1915; Berkeley, September, 1915: Arbutus unedo; Eedlands, February, 1917; Bosa spp. ; Walnut Creek (Davidson) ; Berkeley, February, 1915 (Essig). In 1910 Davidson described a species of Rhopalosiphum, which he named arbuti, from specimens taken on madrone in the vicinity of Stanford University. Since then it has been found quite commonly on madrone throughout the San Francisco Bay region, and once on a strawberry tree in Silva Park, Redlands. It was noticed by the author that the alate females were very scarce at all times, although the apterae and nymphs were often quite abundant. Later, when A SYNOPSIS OF THE APE I DID AE 85 studying specimens while working up a key to the species of Rhopalo- siphum, he found that structurally this species was identical with Rhopalosiphum nervatum Gillette. The latter had been taken on roses in the San Francisco Bay region. The identical structure and the scarcity of alates on madrone led to a belief that they were the same species. However, it was too late in the season (October, 1915) to try any transfer tests. No opportunity was found to try migration tests until in February, 1917, when the species was taken in Redlands. Two alate females were reared in the laboratory and then placed under a muslin bag on a rose bush, out of doors. A few days later these were examined and several young larvae observed. No further observations were made for two weeks, when it was found that the bag had been ripped off by the severe winds. Although this test was not a complete success the author feels confident of the identity of this species. 104. Rhopalosiphum persicae13 (Sulz.) Figures 108, 119, 120, 168 Sulzer, Kan. Ins., p. 105, 1761. Aplite (orig. dese.). Clarke, Can. Ent., vol. 35, p. 252, 1903. Rhopalosiphum dianthi (Schrank) (list). Gillette, Jour. Econ. Ent., vol. 1, p. 359, 1908. Myzus (desc.). Davidson, Jour. Econ. Ent., vol. 2, p. 303, 1909. B. dianthi (Schrank), E. achyrantes Monell, and Myzus (list). Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1910. E. tulipae Thomas (list). Davidson, Jour. Econ. Ent., vol. 3, p. 378, 1910. E. dianthi (Schr.) (list). Davidson, Jour Econ. Ent., vol. 3, p. 379, 1910. Mysus (list). Essig, Pom. Jour. Ent., vol. 3, p. 598, 1911. Myzus (desc.). Eecords. — Throughout California by Clarke, Davidson, Essig, Ferris, Morrison, and the author on Abutilon sp., Amaranthus retro fiexus, Amsinclcia respectabilis, Bougainvillaea sp., Brassica spp., Capsella bursa-pastoris, Capsicum annuum, Catalpa sp., Chcnopodium murale, Citrus spp., Cynoglossum grande, Ci/ticus pro- liferus, Geranium carolinianum, Hedera helix, Lycopersicum esculentum, Malva parviflorus, Oxalis oregona, Prunus spp., Eanunculus califomicus, Eaphanus sativus, Eumex spp., Sambucus glauca, Sanicula menziesii, Senecio vulgare, Solanum tuberosum, Sonchus spp., Tropaeolum sp., Tulipa sp., Vinca major. This green peach aphis is one of the most common aphids found in the state. It is most abundant in the spring, at which time it will be found on almost any plant. According to Gillette various species is George Shinji (Can. Ent., vol. 49, p. 49, 1917) recently described an aphid from specimens taken on Godetia amaena in Berkeley, which he named Myzus godetiae n.sp. The author has not seen specimens of this species, but from the description and figures, it is in all probability Ehopalosiphum persicae (Sulz.). 8t> MISCELLANEOUS STUDIES of Prunus are the winter hosts in Colorado, while during the summer it migrates to other plants. In California, however, winter eggs are not laid, the viviparous females living the year round. So far as the author has observed in over three years, only the form with clavate cornicles is found in California. 105. Rhopalosiphum rhois Monell Figure 173 Monell, U. S. Geol. Geog. Surv., Bull. 5, p. 27, 1879 (orig. desc.). Davis, Can. Ent., vol. 46, p. 165, 1914. E. Iwwardi (Wils.) (desc.). Essig, Univ. Calif. Publ. Ent., vol. 1, p. 330, 1917. B. howardi (Wils.) (list). Ibid., p. 334, 1917 (list). Eecords. — Ehus diversiloba; Berkeley, April, 1915; Avena sativa, Berkeley, (Essig). This species has been taken in Berkeley on poison oak and grasses. Essig reported it recently as R. howardi (Wils.), but according to Gillette14 this is a synonym of R. rhois Monell, Rhus being the winter host, and various species of GramMiaceae the summer hosts. This species does not seem to be a typical Rhopalosiphum, being quite close to Siphocoryne nymphaeae Linn., but yet not fitting the generic description of Siphocoryne exactly. Consequently it is best to list it as has been done heretofore as Rhopalosiphum. . 106. Rhopalosiphum violae Pergande Figures 164, 174 Pergande, Can. Ent., vol. 32, p. 29, 1900 (orig. desc.). Essig, Pom. Jour. Ent., vol. 1, p. 4, 1909 (desc.). Davidson, Jour. Econ. Ent., vol. 2, p. 303, 1909 (list). Davidson, Jour. Econ. Ent., vol. 3, p. 277, 1910 (list). Eecords. — Viola spp. ; Claremont, Santa Paula (Essig); Stanford University (Davidson); Palo Alto, May, 1915; Santa Ana, February, 1917; Eiverside, April, 1917. This beautiful little aphid is found more or less abundantly in the spring on the under side of the leaves of violets throughout the state. The dark red color and broad black wing veins serve to distinguish it readily from other aphids. Gillette, Jour. Econ. Ent., vol. 8, p. 100, 1915. A SYNOPSIS OF TEE APHIDIDAE 87 Tribe Aphidini Wilson Wilson, Ann. Ent. Soc. Am., vol., 3, p. 331, 1910. Following is a brief characterization of this tribe, from Wilson: The characters which separate this tribe from the previous one [Macrosiphini] are taken as follows: Antennae shorter than the body, or when as long as the body the cornicles and cauda are very short; antennal tubercles, when present, are indistinct, or else the cornicles and cauda are small; when the cornicles are very long or large the development is limited and the other characters are used to place the genera. The California genera included by Wilson in this tribe are Aphis, Cerosipha, Coloradoa, Hyalopterus, Liosomaphis, and Siphocoryne [Hyadaphis], In addition to these the author includes Toxoptera because of the small and indistinct antennal tubercles and the short cornicles, and Myzaphis because of the absence of antennal tubercles. The key to the California genera has been formulated by the author, following Wilson, Mordwilko, and Van der Goot. 1. Antennae five-segmented Cerosipha del Guercio — Antennae six-segmented 2 2. Cornicles much shorter than cauda Hyalopterus Koch — Cornicles about as long as or longer than cauda 3 3. Cornicles cylindrical, tapering, or conical, not distinctly clavate (fig. 182), except in Coloradoa and Myzapliis, in which they may be slightly clavate at the apex (fig. 315) 5 — Cornicles distinctly clavate (figs. 183, 184) 4 4. Cornicles long and strongly clavate on one side (fig. 184). Antennae shorter than body, with VI spur not longer than III Liosomaphis Walker — Cornicles slender and but slightly clavate (fig. 183). Antennae never much shorter than body, with VI spur longer than III (fig. 258) or with a supra- caudal tubercle (figs. 255, 256) Siphorcoryne Passerini 5. Third discoidal vein but one-branched (fig. 276). Body without lateral tubercles. Cauda long and prominent, being about as long as cornicles. Toxoptera Koch — Third discoidal vein twice-branched. Body with or without lateral tubercles. Cauda usually distinctly shorter than cornicles 6 6. Front of head with a very distinct tubercle (figs. 308, 313). Body long without lateral tubercles. Cornicles long and often slightly swollen near apex Myzaphis Walker and Coloradoa Wilson 7. Front of head without prominent tubercle (fig. 233). Body more rounded with lateral tubercles on prothorax and seventh abdominal segment, and oftentimes on some of the anterior abdominal segments Aphis Linn. 88 MISCELLANEOUS STUDIES 29. Genus Aphis Linn. Linnaeus, Syst. Nat., 1748. Type Aphis rumicis Linn. KEY TO CALIFORNIA SPECIES Alate viviparous females 1. Abdomen with floceulent masses of wax. Antennae considerably shorter than body, and VI spur shorter than III alamedensis Clarke — Abdomen without such floceulent masses of wax (except perhaps Aphis cooki Essig) _ 2 2. Antennae one and one-half times as long as the body, or more. houghtonensis Throop — Antennae not so much longer than body; when longer, which is seldom, but slightly so 3 3. Abdomen pale yellowish green. Found only on Moms sp inori Clarke — Abdomen darker being black, dark green, yellow. Not found on Moms sp. 4 4. Abdomen dark-green with an orange band between the cornicles. augelicae Koch — Abdomen without such an orange band between the cornicles (sometimes there is a slight orange or reddish coloring between the cornicles of the apterae of Aphis avenae Fabr., but it is not constant) 5 5. Abdomen sage-green with faint lateral spots. Ill with apical one-half con- spicuously darkened and with six large sensoria. VI spur less than one-half as long as III. On Atriplex spp tetrapteralis Cockerell — Not with above combination of characters 6 6. IV with secondary sensoria (fig. 244) 7 — IV without secondary sensoria (fig. 204) 27 7. Cornicles and hind tarsi subequal 8 — Cornicles considerably longer than hind tarsi 17 8. VI spur shorter than III 9 — VI spur equal to or longer than III '. 13 9. Cornicles short and tapering 10 — Cornicles short and incrassate pseudobrassicae Davis 10. V with secondary sensoria. Body slightly pulverulent cooki Essig — V without secondary sensoria. Body not pulverulent 11 11. Less than 12 secondary sensoria on III, arranged in a more or less even line 12 — About 20 to 25 secondary sensoria on III, arranged irregularly along segment (fig. 244) senecio Swain 12. Ill with 9 to 12 sensoria. V and VI base subequal, each being shorter than IV lithospermi Wilson — Ill with 5 to 9 sensoria. IV and V subequal, each being longer than VI base viburnicolens n.sp. 13. Cornicles shorter than hind tarsi. A large black species in life being marked with white bars and cross bands on the abdomen albipes Oestlund — Cornicles and hind tarsi subequal. Body color greenish 14 14. Root-infesting species. Antennae short, scarcely reaching the middle of the abdomen mlddletonii Thomas — Aerial species. Antennae reaching to base of the cornicles, or as long as body 15 15. Cornicles incrassate. A medium-sized species pseudobrassicae Davis — Cornicles cylindrical and tapering slightly. A smaller-sized species 16 A SYNOPSIS OF THE APHIDIDAE 89 16. Cauda shorter than hind tarsi. Ill with 11 to 15 sensoria scattered irregu- larly along segment (fig. 294) marutae Oestlund — Cauda longer than hind tarsi. Ill with 5 to 9 more or less evenly arranged sensoria viburnicolens n.sp. 17. Cornicles equal to or longer than III 18 — Cornicles not as long as III 19 18. Cauda, cornicles, and III subequal. Second branch of third discoidal vein very near to apex of wing spiraecola Patch — Cauda considerably shorter than cornicles or III, the last two being subequal. Second branch of third discoidal about midway between base of first branch and apex of wing oenotherae Oestlund 19. Fore wing with the second branch of the third discoidal arising very near to the apex of the wing. (In a few cases the second branch is not found, but never in both wings) (fig. 191) avenae Fabr. — Venation of fore wing normal (fig. 187) 20 20. Antennae longer than body persicae-niger Smith — Antennae not longer than body 20 21. A pair of small tubercles present on the middle of the seventh and eighth abdominal segments malifoliae Fitch — Such tubercles not present 22 22. V with secondary sensoria. VI spur longer than III 23 — V without secondary sensoria. VI spur at most equal to III 25 23. Beak scarcely reaching second coxae maidis Fitch — Beak reaching beyond second coxae, even to or beyond the third 24 24. Cornicles longer than cauda (figs. 194, 195) and more than twice as long as hind tarsi sambucifoliae Fitch — Cornicles and cauda subequal; the former not more than twice as long as hind tarsi neomexicana Cockerell var. pacifica Davidson 25. Cauda and hind tarsi subequal. Ill with a few large sensoria (fig. 232). Abdomen green with dark dorsal markings ramona Swain — Cauda longer than hind tarsi. Ill with several sensoria. Abdomen black or dark brown 26 26. Cornicles more than twice as long as hind tarsi, often almost three times as long. VI spur and cornicles subequal, hind tarsi and. VI base subequal. hederae Kalt. — Cornicles never more than twice as long as hind tarsi, usually considerably less. Hind tarsi usually slightly longer than VI base, and VI spur longer than cornicles euonomi Fabr. 27. Cornicles distinctly knobbed, the tip being widened to twice the width of the rest of the cornicles frlgidae Oestlund — Cornicles normal 28 28. Fore wing with the second branch of the third discoidal arising very near the apex of the wing (fig. 188) salicicola Thomas — Fore wing with venation normal (fig. 187) 29 29. Cornicles distinctly longer than cauda 31 — Cornicles at most equal to cauda 30 30. Cornicles short and swollen throughout apical one-half (fig. 203). Antennae as long as or longer than the body .„ brassicae Linn. — Cornicles short and slender, and slightly clavate on one side. Antennae scarcely two-thirds as long as the body atriplicis Linn. 31. Abdomen without lateral tubercles on anterior segments. Cauda short and broad, with rounded tip, and almost as long as the cornicles cardui Linn. — Abdomen with lateral tubercles on at least one of the anterior segments .... 32 90 MISCELLANEOUS STUDIES 32. VI spur shorter than III 33 — VI spur not shorter than III 34 33. Cornicles about three times as long as cauda medlcaginis Koch — Cornicles not three times as long as cauda 34 34. Cauda more than one-half as long as cornicles 35 — Cauda not more than one-half as long as cornicles 38 35. Ill with four or five fairly large semsoria oregonensis Wilson — Ill with many irregular sensoria 36 36. Ill with 20 or more sensoria, IV with none 37 — Ill with less than 20 sensoria, usually 14 or 15. IV usually with one or two, or. more sensoria euonomi Fabr. 37. IV about one-third longer than V. Cornicles about four times as long as broad at base. On Heraclium spp heraclii Cowen — IV but about one-sixth longer than V. Cornicles about three times as long as broad at base. On Yucca sp Yuccae Cowen 38. A few (about 10) equal-sized sensoria on III (fig. 222). A large yellow species with distinct dark markings nerii Fonsc. — About 20 irregular sensoria on III (fig. 211). Not yellow 39 39. Cornicles slightly more than twice as long as hind tarsi 40 — Cornicles not twice as long as hind tarsi carl Essig 40. Hind tarsi slightly longer than cauda ceanothi Clarke — Hind tarsi shorter than cauda cornifoliae Fitch 41. VI spur one and one-half or more times as long as III setariae Thomas — VI spur never so much longer than III 42 42. Ill with a few large circular sensoria (5-10) (figs. 226, 290) _ 43 — Ill with several (15 or more) irregular sensoria 45 43. Beak reaching to or beyond third coxae. IV never with sensoria. gossypii Glover — Beak not reaching third coxae 44 44. VI spur longer than III (fig. 226). Small size pomi de Geer — VI spur subequal to or shorter than III (figs. 289, 290). Medium to large size cerasifoliae Fitch 45. Cornicles twice as long as cauda. Femora of all three pairs of legs similarly colored carl Essig — Cornicles longer than cauda, but not twice as loag. Femora of first pair of legs pale, of second and third pair black euonomi Fabr. Apterous viviparous females^ 1. Cornicles shorter than hind tarsi 2 — Cornicles equal to or longer than hind tarsi 4 2. VI spur longer than III. White bars and bands on abdomen in life. albipes Oestlund — VI spur not longer than III. Abdomen not as above 3 3. Cornicles and cauda subequal. Beak not reaching to second coxae. Pul- verulent brassicae Linn. — Cornicles shorter than cauda. Beak reaching to or beyond second coxae. Not pulverulent atriplicis Linn. is In this key only those species are included of which there are specimens in the author's collection or of which there are adequate descriptions available. The following species are therefore omitted: Aphis alamedensis Clarke, A. hough- tonensis Throop, A. mori Clarke, A. neomexicana Cockerell, A. oenotherae Oest- lund, and A. tetrapteralis Cockerell. A SYNOPSIS OF THE APHIDIDAE 91 4. Cornicles and hind tarsi subequal 5 — Cornicles longer than hind tarsi „ 10 5. Secondary sensoria on III and IV. Boot species _ middletonii Thomas — No secondary sensoria. Aerial species 6 6. Ill longer than VI spur 7 — Ill shorter than or at most equal to VI spur 8 7. IV and cornicles subequal Jithospermi Wilson — IV shorter than cornicles. Pulverulent cook! Essig 8. IV and cornicles subequal. Antennae considerably more than one-half the length of the body 9 — IV shorter than cornicles. Antennae at most one-half the length of the body. senecio Swain 9. Cornicles twice as long as cauda and slightly swollen before the tip. avenae Fabr. — Cornicles not twice as long as cauda, cylindrical, and tapering toward tip. marutae Oestlund 10. Cornicles less than twice as long as hind tarsi 11 — Cornicles twice as long as or longer than hind tarsi 21 11. Secondary sensoria on III and IV. Eoot-infesting species. middletonii Thomas — No secondary sensoria. Aerial species 12 12. VI spur longer than III „ 13 — VI spur at most equal to III 16 13. Ground color, black or dark brown 14 — Ground color, a shade of green 15 14. VI spur one and one-half to two times as long as III. Apex only of femora dusky setariae Thomas — VI spur but slightly longer than III. Apical one-half of femora dusky. medecaginis Koch 15. Pale green. Cornicles and cauda subequal. Dark, mottled green. Cornicles twice as long as cauda or longer avenae Fabr. 16. VI spur considerably shorter than III 17 — VI spur almost as long as III 18 17. Cornicles swollen toward tip pseudobrassicae Davis — Cornicles cylindrical and tapering toward tip ramona Swain 18. Cornicles but slightly longer than hind tarsi 19 — Cornicles about one and one-half times as long as hind tarsi 20 19. Dark green. Cornicles at least three times as long as broad at base. maidls Fitch — Pale green. Cornicles at most twice as long as broad at base. senecio Swain 20. Dark green to reddish yellow. On Yucca spp yuccae Cowen — Black or very dark brown with black dorsal bands and spots. On various plants euonomi Fabr. 21. Cornicles distinctly knobbed at tip frigidae Oestlund — Cornicles normal 22 22. VI spur longer than II '. 23 — VI spur at most equal to III 25 23. Pale green with dusky dorsal abdominal markings calendulicola Monell — Not colored as above, either not green, or if green with dusky dorsal abdom- inal markings 24 92 MISCELLANEOUS STUDIES 24. Bright yellow with black markings. Cornicles at least three times as long as hind tarsi nerii Fonsc. — Dark green with black markings. Cornicles but about twice as long as hind tarsi cardui Linn. 25. Cornicles longer than III 26 — Cornicles at most equal to III 29 26. Ill considerably longer than VI spur 27 — Ill subequal to or but slightly longer than VI spur 28 27. Black. Cornicles about three times as long as hind tarsi. Ill one and one- half times as long as VI spur sambucif oliae Fitch — Green, pale to apple. Cornicles about four times as long as hind tarsi. Ill almost twice as long as VI spur salicicola Thomas 28. Cornicles subequal to or but slightly longer than III, and about twice as long as cauda prunorum Fabr. — Cornicles one and one-half to two times as long as III, and about four times as long as cauda oregonensis Wilson 29. Cornicles considerably shorter than III 30 — Cornicles subequal to or but slightly shorter than III 37 30. Ill and IV spur subequal persicae-niger Smith - Ill longer than VI 1 31 31. Cornicles at least twice as long as cauda 36 — Cornicles not twice as long as cauda 32 32. Pale green, pulverulent cerasifoliae Fitch — Dark green, brown, or black, not pulverulent 33 33. Cornicles about three times as long as hind tarsi 34 — Cornicles not three times as long as hind tarsi 35 34. Ill with a few small secondary sensoria hederae Kalt. — No secondary sensoria .- cornifoliae Fitch 35. Cornicles considerably more than twice as long as hind tarsi. Lateral abdom- inal tubercles only on first and seventh segments heraclii Cowen — Cornicles at most but slightly more than twice as long as hind tarsi. Lateral tubercles usually on more than first and seventh segments .... euonomi Fabr. 36. Antennae about as long as body. Cornicles more than twice as long as Cauda cari Essig — Antennae but about one-half as long as body. Cornicles but about twice as long as cauda gossypii Glover 37. Ill considerably longer than VI spur : 38 — Ill and VI spur subequal 40 38. A pair of dorsal abdominal tubercles on sixth and seventh segments. malifoliae Fitch — No dorsal abdominal tubercles on sixth and seventh segments 39 39. Cornicles green, cylindrical, tapering slightly toward tip, and fairly straight. Cauda about one and one-half times as long as hind tarsi. Abdomen with- out dusky dorsal markings ramona Swain — Cornicles black, cylindrical, curved outward. Cauda and hind tarsi subequal. Abdomen with dusky dorsal markings seanothi Clarke 40. VI spur slightly longer than III. Cornicles and cauda subequal. viburnicolens n.sp. — VI spur slightly shorter than III. Cornicles one and one-half times as long as cauda pomi De Geer A SYNOPSIS OF THE APHIDIDAE 93 107. Aphis alamedensis Clarke Clarke, Can. Ent., vol. 35, p. 251, 1903 (orig. desc.). Record. — Prunus domestica; Berkeley (Clarke). This is an unknown species described from specimens taken by Clarke on greengage plum in Berkeley. Davidson suggests that it might be Aphis cardui Lirin. (pruni Koch) from its brief description. 108. Aphis albipes Oestlund Figures 198 to 200 Oestlund, Geol. Nat. Hist. Surv. Minn., Bull. 4, p. 52, 1887 (orig. dese.). Williams, Univ. Neb. Studies, vol. 10, p. 119, 1910 (desc.). Davidson, Jour. Econ. Ent., vol. 3, p. 376, 1910 (list). Records. — Symphoricarpus racemosus; Stanford University (Davidson) ; Con- gress Springs, Santa Clara County, July, 1915 (McCraeken) ; Berkeley, July, 1915 (Shinji). This species is found at times curling the leaves of snowberry in the San Francisco Bay region. Dr. McCraeken noted in connection with the infestation at Congress Springs, "they are quite prettily patterned with white bars and cross-bars." This is usually enough to distinguish them. 109. Aphis angelicae Koch. Koch, Die Pflanzenlause, p. 521, 1854 (orig. desc.). Wilson, Jour. Econ. Ent., vol. 2, p. 348, 1909 (desc.). Record. — Angelica sp., Hedera sp. ; California (Wilson). Wilson reported this species from California, but gave no locality or date. It is unknown to the author. 110. Aphis atriplicis Linn. Linnaeus, Fauna Sweden, p. 1000, 1761 (orig. desc.). Hayhurst, Ann. Ent. Soe. Am., vol. 2, pp. 88-100, 1909 (desc.). Davidson, Jour. Econ. Ent., vol. 5, p. 407, 1912 (desc. sexuales apterous viviparae). Davidson, Jour. Econ. Ent., vol. 7, p. 133, 1914 (desc. fundatrix). Records. — Chenopodvum album, C. murale; San Jose, Walnut Creek (David- son). 94 MISCELLANEOUS STUDIES This has been reported twice from pigweed or goosefoot in the San Francisco Bay region, where Davidson states that it is very common. The sexes occur in October. Davidson believes that there is an alternate host, but as to what it might be, he is uncertain. The author has never collected specimens, but has had access to material taken by R. W. Doane on Chenopodium in Utah in August, 1916. 111. Aphis avenae Fabr. Figures 191, 201, 202 Fabricius, Ent. Syst, p. 736, 1775 (orig. desc.). Clarke, Can. Ent., vol. 35, p. 254, 1903 . Nectarophora (list). Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1910. Siphocoryne (list). Essig, Pom. Jour. Ent., vol. 3, p. 465, 1911. A. padi Linn. (list). Essig, Pom. Jour. Ent., vol. 4, p. 790, 1912. A. maidis Fitch (desc). Smith, Mon. Bull. Cal. Comm. Hort., vol. 3, p. 116, 1914 (list). Davidson, Mon. Bull. Cal. Comm. Hort., vol. 6, p. 65, 1917 (note). Records. — Graminaceae (various spp.) ; California, December to May (David- son, Essig, Morrison, author) : PJialaris arundinacea; Stanford University, May to July, 1915: Dracaena draco; Stanford University, June, 1915: Musa sapientum; San Diego, March, 1916: Typha latifolia; (Davidson). This is an abundant species through the state, occurring during the late winter and spring on grasses and grains, migrating to other hosts as these become ripened and dried. The life history of this species, according to Davis (U. S. Dept. Agr., Bull. Ill, April, 1914), is somewhat as follows: The spring colonies on grains and grasses originate from viviparous females which passed the winter on the grains and grasses, or from spring migrants from the apples or related fruits; i.e., the progeny of the aphids hatching from eggs laid the previous fall on such trees. As the weather becomes cooler they seek the lower parts or the roots of wheat and other plants of the grass family, and here pass the winter as viviparous females; or the winged fall migrants from the grain may seek such trees as the apple, where the true sexes are produced. Undoubtedly the most common method of wintering over in Cali- fornia is on the roots and lower parts of the grains and grasses. This species has never been collected on apples or other related trees in this state, nor have the eggs ever been observed. During the early spring it is found abundantly on the grains and small grasses, in January and February in the southern part of the 'state, and during April and May in the central part. As the grains ripen and the stalks and leaves become hardened, it seems that the aphids migrate to other varieties of grass which remain soft and green later, as canary grass and reed grass and corn, or even to such hosts as the A SYNOPSIS OF THE APHIDIDAE 95 dragon tree, cat-tail rush, and the banana. But the winter is spent as viviparous females on the grains and grasses. This species has been confused many times with other species infesting grains, such as Macrosiphum granarium (Kirby) and Tox- optera graminum (Rond.). As the latter does not occur in this state it cannot be confused here with Aphis avenue Fabr. Clarke listed this as Nectarophora avenue Fabr., so it appears that he might have had Macrosiphum granarium (Kirby) in mind, as it is highly improbable that he could have confused Aphis av&nae Fabr. with a species of Macrosiphum (Nectarophora). The cornicles of avenae Fabr., the absence of antennal tubercles, and the irregular venation make it quite easily distinguishable. The cornicles are quite short, as com- pared with a species of Macrosiphum, and distinct antennal tubercles are entirely lacking. The third discoidal vein of the forewing is typically twice-branched, but the second is close to the apex of the wing, and sometimes is entirely lacking. The only other species of Aphis in this state with this character is Aphis salicicola Thomas, found on willows. These two are readily distinguished from each other by the comparative lengths of the cornicles, which are consider- ably longer in salicicola Thomas than in avenae Fabr. 112. Aphis brassicae Linnaeus Figures 203, 204 Linnaeus, Syst. Nat., vol. 2, p. 734, 1735 (orig. desc.). Clarke, Can. Ent., vol. 35, p. 250, 1903 (list). Davidson, Jour. Econ. Ent., vol. 2, p. 302, 1909 (list). Davidson, Jour. Econ. Ent., vol. 3, p. 376, 1910 (list). Davidson, Pom. Jour. Ent., vol. 3, p. 399, 1911 (list). Essig, Pom. Jour. Ent., vol. 3, p. 523, 1911 (desc.). Record. — Cruciferae (various spp.) ; throughout California. During the late winter and spring cruciferous plants are often heavily infested with this species. Of the cultivated plants cabbages and radishes seem to be most heavily infested ; while the wild mustard and radish often have the entire flower clusters covered with these aphids. Oftentimes in the colonies of this species are also found Aphis pseudobrassicae Davis, Rhopalosiphum lactucae (Kalt.), and R. persicae (Sulz.). In southern California the colonies are always attacked by the braconid fly, Diaretus rapae Curtiss, and a large per- centage of the individuals destroyed. As summer comes on these para- sites and such predators as syrphids and ladybirds usually get the best of the aphids, which disappear to a large extent until fall. 96 MISCELLANEOUS STUDIES 113. Aphis calendulicola Monell Monell, U. S. Geol. Geog. Surv., Bull. 5, p. 23, 1879 (orig. desc.). Clarke, Can. Ent., vol. 35, p. 250, 1903 (list). Eecord. — Calendula officinale; Berkeley (Clarke). This species has not been recognized since Clarke 's report of it on marigold. It is possible that he had Aphis senecio Swain, which is very common on marigolds throughout the state. 134. Aphis cardui Linn. Figures 208, 209 Linnaeus, Syst. Nat., vol. 2, p. 735, 1735 (orig. desc.). Games, Mon. Bull. Gal. Comm. Hort., vol. 1, p. 399, 1912. Aphis pruni (list). Davidson, Jour. Econ. Ent., vol. 5, p. 407, 1912 (list). Patch, Maine Agr. Exp. Sta., Bull. 233, p. 263, 1914 (desc.). Records. — Cirsium sp. ; San Jose (Davidson); Berkeley, June, 1915: Prunu-s domestica; Orangevale, Sacramento County (Carnes) ; Walnut Creek (Davidson) ; Berkeley, March, 1916 (Essig). According to Patch this thistle aphid is the same as the one infest- ing plums and formerly known as A. pruni Koch. Both are abundant in the San Francisco Bay region, pruni being found in the fall and spring on plum, cardui during the summer on thistle. The author has attempted no transfer tests, so accepts Patch's statement as authority for the synonymy. It is certain that structurally these are strictty identical. 115. Aphis cari Essig Essig, Univ. Calif. Publ. Entom., vol. 1, pp. 317-321, 1917 (orig. desc.). Eecord. — Carum kelloggii; Eutherford, Napa County (Essig) ; Angelica tomentosa; Berkeley (Essig). Essig recently described this from specimens taken on wild anise in Rutherford. The author has seen cotype specimens, but has never collected the species. 116. Aphis ceanothi Clarke Figures 210, 211 Clarke, Can. Ent., vol. 35, p. 250, 1903 (orig. desc.). Davidson, Jour. Econ. Ent., vol. 2, p. 302, 1909 (list). Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1910 (list). Essig, Pom. Jour. Ent., vol. 3, p. 525, 1911. Aphis ceanothi-hirsuti n. sp. (dese.). A SYNOPSIS OF THE APHIDIDAE 97 Records. — Ceanothus integcrrimus; Coif ax, Placer County (Clarke) ; Witch Creek, San Diego County, June, 1916: C. cuneatus; Stanford University (David- son), November, 1910 (Morrison), October, 1915 (R. A. Vickerey) : C. thysiflorus; Bear Creek Gulch, Santa Clara County, April, 1911 (Morrison) : C. hirsuti; Santa Paula (Essig). This is a widely distributed species, having been found on Ceano- thus as far north as Placer County, and as far south as San Diego County. It is seldom abundant, however. The species that Essig described as A. ceanothi -hirsuti n.sp. is undoubtedly the same as Clarke described. 117. Aphis cerasifoliae Fitch Figtures 288 to 292 Fitch, Eept. Ins. N. Y., vol. 1, p. 131, 1855 (orig. desc.). Patch, Maine Agr. Exp. Sta., Bull. 233, p. 260, 1914 (desc.). Record. — Prunus emarginata; Wynola, San Diego County, June, 1916. This aphid was found abundantly curling the terminal leaves of wild cherry near Wynola (3700 feet altitude), San Diego County, in June, 1916. Alate and apterous viviparous females as well as nymphs were abundant in the curled leaves. The apterae and nymphs were slightly pulverulent. This species corresponds very closely to Aphis cerasifoliae Fitch as described by Patch (op. cit.), although there are some minor differences. Following is a copy of Patch 's description of the Maine specimens of this species : . This well defined species is common on both the native choke cherry, Prunus virginiana, and the western P. demissa Walp. introduced in a nursery row on our campus. Apterous female. — Head, pale green or water whitish, beak short, extending to second coxae, eyes, antennae with I, II and III concolorous with head, distal half darker to black, III with no sensoria, proportions as shown in figure; pro- thorax pale green, lateral tubercles present; thorax green with dark green mid- dorsal line, femora and tibiae pale and tarsi black; abdomen pulverulent, pale green with dark green median line and dark green transverse lines between seg- ments, lateral tubercles present, cornicles pale with dusky tips, slender, slightly tapering, and approximately twice the tarsus in length, cauda white with dark tip; conical, being broad at base and abruptly tapering. Nymphs and pupae are also pulverulent and have dark green middorsal and transverse intersegmental line, though these are not always well defined in the pupa which has two lateral dark green lines on thorax. Alate female. Head black, beak short, not reaching to second coxae, eyea black, antennae dark, III with from about 12 to 18 large sensoria about the size of the terminal one on V, IV with from none to several sensoria like those on III, proportions of joints as shown in the figure; prothorax green with black trans- verse band, lateral tubercles present; thorax black, wings iridescent with slender brown veins and large dusky stigma with pointed tip; commonly though not 98 MISCELLANEOUS STUDIES always with second branch very short, abdomen glabrous, rather bright though not vivid green, median line dark green, sutural lines dark green ending in marginal green dots, cornicles dark, cauda green. Aphis cerasifoliae is gregarious on the ventral surface of the terminal leaves badly curling and deforming them. A copious amount of honeydew is present, and ants are usually found attending a colony of this species. The specimens from Wynola agree very well with this description, although as stated above, there are a few minor points of difference. However, as Dr. Patch writes: "It seems too close to cerasifoliae to give it a distinct name," and "if the appearance in life answers my description of cerasifoliae I should be inclined to call it that. It hap- pens to be a species as characteristic alive as dead." Following are the notes the author took of its appearance alive, before he suspected its identity: "Alates, apterae and nymphs abundant on terminal leaves curling them badly. Large amount of honeydew and many ants in attendance. Apterae and nymphs pulverulent." These notes agree exactly with Patch 's notes, cited above. Following is a brief description of specimens taken at Wynola on July 8 : Apterous viviparous female. — Prevailing color pale apple green, pulverulent. Head luteous. Thorax and abdomen pale green with middorsal longitudinal stripe darker green. Antennae with the three basal joints luteous, the three apical joints shading into black. Pri- mary sensoria on V and VI, accessory sensoria on VI, no secondary sensoria. Ill and spur are subequal, or III slightly the longer. IV and V subequal and a little more than one-half as long as III. In some cases IV is slightly longer than V. VI is about one-fourth as long as its spur, longer than I, which in turn is longer than II. The antennae are longer than the body. Cornicles long, slightly tapering, pale with tip dusky, about equal in length to the fifth antennal seg- ment and about twice the length of the hind tarsus. Cauda long, conical, and about two-thirds the length of the cornicles, pale with tip dusky. Lateral tubercles are present on the first and seventh abdom- inal segments and on one other of the abdominal segments, in some cases on the second, in others! on the third, and in others on the fourth. Measurements (of specimens mounted in Canadian balsam) : Body length, 1.5 to 1.53 mm.; body width (abdomen), 0.247 mm.; antennae total, 1.445 to 1.734 mm. (av. 1.6082 mm.) ; I, 0.085 to 0.117 mm. (av. 0.0987 mm.) ; II, 0.068 mm.; Ill, 0.408 to 0.467 mm. (av. 0.4335 mm.) ; IV, 0.238 to 0.306 mm. (av. 0.272 mm.) ; V, 0.221 to 0.233 mm. (av. 0.224 mm.) ; VI, 0.1105 to 0.119 mm. (av. 0.1169 mm.) ; spur, A SYNOPSIS OF THE APHIDIDAE 99 0.408 to 0.45 mm. (av. 0.4186 mm.) ; cornicles, 0.221 to 0.255 mm. (av. 0.2401 mm.); cauda, 0.15 mm.; hind tarsi, 0.12 to 0.135 mm. (av. 0.1275 mm.). Alate viviparous female. — Prevailing color pale to apple green. Head, antennae, thorax, marginal spots on abdomen, cornicles, tip of cauda, femora, and tarsi all black. Antennae (fig. 289, 290) with the usual primary sensoria on V and VI and the usual accessory sensoria on VI. IV without sensoria and III with from 6 to 11 fairly large circular secondary sensoria, the usual number being 8 (fig. 290). In this character it differs most markedly from the Main specimens, which have from 12 to 18 sensoria on III and from none to several on IV. The antennae are slightly shorter than the body although practically of the same length. Ill is the longest segment, closely followed by the spur, then by IV, V, VI, I and II. Ill and the spur are subequal, or either one or the other may be slightly the longer. In Patch's drawing V is a little longer than IV. In the California specimen IV is always slightly the longer of the two. In all the California specimens the antennal segments are all a little shorter than in the Maine material. Lateral tubercles are present on the pro- thorax; they are always present on the seventh abdominal segment, and may be present on any of the first few segments of the abdomen as well. In one case they were observed on the second and seventh segments, in another on the second, third, and seventh, in still another on the fourth, fifth, and seventh, and in a fourth case on the first, second, third, fourth, and seventh segments (fig. 292). The wings and venation are normal, with the second branch of the cubitus arising nearer to the tip of the wing than to the base of the first branch (fig. 291). However, it is not quite so close to the wing tip as in the Maine specimens. The cornicles (fig. 292) are long and cylindrical. They are equal to or slightly shorter than V, and from one and one-half to two times as long as the hind tarsi. The cauda (fig. 292) is more or less ensiform, about one-half as long as the cornicles, reaching to the tip of the cornicles, and subequal to or slightly shorter than the hind tarsi. Measurements (of specimens mounted in Canadian balsam) : Body .length, 1.53 to 1.65 mm. (av. 1.585 mm.) ; width of thorax 0.697 to 0.765 mm. (av. 0.731 mm.), antennae total, 1.568 mm.; I, 0.068 to 0.085 mm. (av. 0.0765 mm.) ; II, 0.051 mm.; Ill, 0.331 to 0.408 mm. (av. 0.3644 mm.) ; IV, 0.238 to 0.289 mm. (av. 0.2817 mm.) ; V, 0.221 to 0.247 mm. (av. 0.2295 mm.); VI base, 0.085 to 0.111 mm. (av. 100 MISCELLANEOUS STUDIES 0.1015 mm.) ; VI spur, 0.391 mm.; cornicles, 0.204 to 0.246 mm. (av. 0.2179 mm.) ; cauda, 0.103 to 0.119 mm. (av. 0.1084 mm.) ; hind tarsi, 0.136 mm. 118. Aphis cooki Essig Figures 212 to 214 Essig, Pom. Jour. Ent., vol. 2, p. 323, 1910. Aphis gossypii Glover (desc.). Essig, Pom. Jour. Ent., vol. 3, p. 587, 1911 (orig. desc.). Record. — Citrus sp., Pomona (Essig). In 1909, C. H. Vary, county horticultural inspector in Pomona, found a few orange trees heavily infested with this aphid. Prompt control measures were taken and since then it has never again been observed. Essig first thought it to be Aphis gossypii Glover and de- scribed it under that name. Later, however, he found it to be an undescribed species, so named it Aphis c&oki n.sp. after Dr. A. J. Cook. 119. Aphis cornifoliae Fitch Fitch, Cat. Homop. N. Y., p. 65, 1851 (orig. desc.). Records. — Cornus pubescens, Sanicula mensiesii; San Francisco Bay region (Davidson). A species comparing very favorably with this has been taken by Davidson a number of times in the San Francisco Bay region. The fall and winter is spent on dogwood, the summer on gambleweed. Davidson writes as follows : This aphid [from Sanicula] certainly appears to be very close to what I have called (after Gillette) cornifoliae. Moreover, I have noticed that the two plants, dogwood and Sanicula, frequently grow near each other and that there appeared to be a migration of alates from the former just about the time there was a migration of the alates to the latter. This migration took place the latter part of April in 1916. 120. Aphis crataegifolii Fitch Fitch, Cat. Homop. N. Y., p. 66, 1851 (orig. desc.). Sanborn, Kan. TJniv. Sei. Bull. 3, p. 53, 1904 (desc.). Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1910 (list). Record. — Crataegus oxycantha; San Jose, Palo Alto (Davidson). This has been reported more or less abundant on hawthorne in the San Francisco Bay region. According to A. C. Baker this is a good and distinct species and not a synonym of Aphis pomi De Geer, as formerly believed. X A SYNOPSIS OF THE APHIDIDAE 101 121. Aphis euonomi Fabr. Figures 182, 187, 190, 205 to 207, 236, 237 Fabricius, Syst. Ent., p. 736, 1794 (orig. desc.). Davidson, Jour. Econ. Ent., vol. 2, p. 302, 1909. A. rumicis Linn, (list, in part?). Essig, Mon. Bull. Cal. Comm. Hort., vol. 4, p. 446, 1915. A. rumicis Linn. (list). Becords — Althaea rosea, Berkeley, June, 1915; Hisbiscus moscheutos, Berkeley, July, 1915 : Maytenus boaria, Berkeley, July, 1915 ; Mesembryanthemum equilat- erale, Stanford University, June, 1915; Silybum marianum, Stanford University, July, 1915: Urtica holoserica, Menlo Park, San Mateo County, January, 1915: Calendula officinale, Orange, February, 1917: Antliemis sp., Pasadena, April, 1917: Papaver sp., El Cajon, San Diego County, May, 1916 (Aphis papaveris Fabr.?) : Vicia fdba, Stanford University (Davidson), Oxnard (Essig, 1915), Montebello, Los Angeles County, December, 1916, Eiverside, January to May 1917 (Aphis fabae Scop.?): Eumex spp., Palo Alto, January, 1912 (Davidson), Stanford University, March, 1912 (Morrison), March, 1915, Ventura County, May, 1917: Pliaseolus spp., Ventura County, May, 1917 (Aphis rumicis Linn.?). There has been a great deal of confusion regarding the identity of this species of aphid, and as yet its synonomy is not worked out satisfactorily. The following is offered only provisionally by the author. The common black aphid has usually been considered as Aphis rumicis Linn., Aphis euonomi Fabr. being taken as a synonym, but according to Gillette, Linnaeus' description calls for an aphid ' ' brass}1- brown in color, and not black according to the popular opin- ion; and its food plant should be species of Eumex." He considers the common black species to be Aphis euonomi Fabr., as does Mord- wilko in the European form. The author follows these two aphidol- ogists in placing Aphis rumicis Linn, of American authors (and later European authors) as a synonym of Aphis euonomi Fabr. He (i.e., Gillette) writes, "whether or not it is synonymous with rumicis we are not certain, but we very much doubt this being the case." As long ago as 1894, Osborn and Sirrine (Iowa Agr. Sta., Bull. 26, p. 904, 1894) proved that the species which wintered in Iowa on Euonymus migrated to Eumex and other plants in the summer. In California the author has been unable to find it at any time upon Euonymus, although this is a very common ornamental plant, especi- ally in the vicinity of Riverside. This may be due, however, to the mild winter climate of southern California, which permits plant lice to live throughout the winter, thus not necessitating the laying of eggs. Concerning the identity of the California species the author believes the form described briefly below to be Aphis euonomi Fabr. The 102 MISCELLANEOUS STUDIES one following is probably the same species, and is the one described as Aphis papaveris by Fabricius. The species from Vicia faba is probably the species described as Aphis fabae Scop., which may be synonymous with Aphis eiwnomi Fabr., but again may not be. The author tried a few transfer tests this spring (1917) with the form from Vicia, attempting to colonize it on Hedera helix and on Rumex spp., with negative results. Of course, this does not prove that it will not colonize on these plants, although the author has come to the conclu- sion that the Hedera species is entirely different, being Aphis hederae Kalt. Dr. Patch16 in her interesting paper on aphid ecology makes the following statement regarding migration tests, which, it seems to the author, it is well to remember when making such tests : If an investigator fails in one hundred attempts to colonize thistle with migrants from plum, that will not be a safe reason for him to conclude that he is not working with Aphis cardui, or that this thistle aphid has nothing to do with the leaf deformations of the plum in the spring. It has been my experience that negative data with aphids under such conditions are just no data at all. If the structural characters are such as warrant the migration test in the first place, they warrant a patient continuation even in the face of repeated failures. On the other hand (and this is a most encouraging and stimulating circum- stance in connection with aphid migration tests), a single success goes a long way to prove the case. Barring complications, a single success is enough, and repe- titions and verifications are needed only as safeguards in that respect. The third description is from specimens taken on Rumex spp. and although slightly different from the one considered as Aphis eiwnomi Fabr., it may be the same, and it may be Aphis rumicis Linn., but of this the author is doubtful. In the bean fields of Ventura County, this black bean aphis is very abundant, and often does considerable damage. In May, 1917, the bean plants were just beginning to appear, and as yet were not infested with the aphis. However, the native dock was quite heavily infested. It seems that the aphis lives over the winter on dock and perhaps on other native plants, migrating in the early summer to the beans. Here it lives throughout the summer, returning to dock when the beans have been harvested and the plants plowed under. Horti- cultural Commissioner A. A. Brock, of Ventura County, places great hope in the efficiency of Hippodamia convergens Guerin as a con- trolling factor. In the spring of 1917 he collected a vast number of these ladybird beetles in Sespe Canyon and turned them loose in the bean fields just as the aphids were beginning to appear. At the present time the results are unknown. !« Patch, Edith M., Concerning problems in Aphid ecology, Jour. Econ. Ent., vol. 9, pp. 44-51, 1917. A SYNOPSIS OF THE APHIDIDAE 103 The following brief description was made from specimens col- lected from the first six host plants listed above, and is the one con- sidered as Aphis euonomi Fabr. Alate viviparous female. — Color apparently black, but on close examination it seems that the ground color is a very dark brown, covered with a blackish tinge, with the following parts decidedly black: head, antennae, thoracic lobes, marginal spots and transverse bands on the abdomen, cornicles, tarsi, coxae, tips of tibiae, and apical one-half to two-thirds of the middle and hind femora.' The tibiae and fore femora are pale, appearing whitish in life. The antennae are shorter than the body, III being the longest segment, followed closely by VI spur. In one case VI spur was slightly longer than III and in another equal to III. In all other specimens III was the longer segment. IV and V are subequal, V usually being slightly the shorter. There are from eleven to twenty-one secondary sensoria on III, of irregular size. These are scattered along the whole length of the segment, the distal five or six being in a more or less even line. The usual number is about twelve to fourteen. The number of secondary sensoria on IV range from none to seven, the modal number being two. In one specimen only were sensoria absent from IV; in another, one antenna had seven, the other having two, while in a third, one antenna had five, the other six. When there are more than two or three sensoria, they are all quite small, and can be clearly distinguished only by the higher power of a microscope. Two is the usual number, being located about the middle of the segment. V is usually without secondary sensoria, the primary sensorium being always present, however. In one specimen the antennae had one or two very small secondary sensoria on V, and in another specimen one antenna had one small sensorium, the other none. The usual primary and accessory sensoria are present on VI base. Lateral abdominal tubercles are always present on the seventh segment, usually on the first, and often on the second, third, fourth, or fifth. There are always at least three pair of these tubercles, and oftentimes more. One specimen had tubercles on the first, second, third, fourth, and seventh segments. The cornicles are black, imbricated, and taper noticeably from base to apex. They are quite constant in length, the variation being not more than 0.05 mm. in all the specimens examined. They are about half as long again as the hind tarsi. The cauda is concolorous with the abdomen, short and conical or ensiform, and subequal in length to the hind tarsi. The wings are normal, with the typical Aphis venation. 104 MISCELLANEOUS STUDIES Measurements: Body length, 1.53 to 1.989 mm. (av. 1.74 mm.); width of thorax, 0.68 to 0.918 mm. (av. 0.765 mm.) ; antennae total, 1.122 to 1.36 mm. (av. 1.272 mm.) ; III, 0.289 to 0.425 m.m (av. 0.3648 mm.) ; IV, 0.1955 to 0.272 mm. (av. 0.2266 mm.) ; V, 0.187 to 0.221 mm. (av. 0.1885 mm.) ; VI, base 0.102 to 0.136 mm. (av. 0.1119 mm.) ; VI, spur 0.289 to 0.357 mm. (av. 0.3145 mm.) ; cornicles, 0.1785 to 0.221 mm. (av. 0.2118 mm.) ; cauda, 0.136 to 0.162 mm. (av. 0.14875 mm.) ; hind tarsus, 0.136 to 0.152 mm. (av. 0.1372 mm.). Specimens taken by the author in May, 1916, on Papaver sp. (cul- tivated poppy) near El Cajon, San Diego County, seem to him to be Aphis papaveris Fabr. (Genera Insectorum, p. 303, 1717), and prob- ably are the same as the above species, although they may be different. There are from thirteen to fifteen irregular secondary sensoria on III as above, but IV and V are without secondary sensoria, with one exception, in which there was one small sensorium near the middle of IV. The cauda is equal to the hind tarsi, the cornicles being longer, and about the same comparative length as above. The third antennal segment appears to be longer in comparison than above in some speci- mens. Lateral abdominal tubercles are present on the first, third, and seventh abdominal segments. Measurements: Body length, 1.486 to 1.908 mm. (av. 1.711 mm.) ; width of thorax, 0.595 to 0.765 mm. (av. 0.68 mm.) ; antennae total, 1.224 to 1.343 mm. (av. 1.2878 mm.) ; III, 0.323 to 0.374 mm. (av. 0.3536 mm.) ; IV, 0.2125 to 0.22 mm. (av. 0.2193 mm.) ; V, 0.187 to 0.204 mm. (av. 0.2024 mm.) ; VI, base 0.102 to 0.119 mm. (av. 0.1054 mm.) ; VI, spur 0.255 to 0.34 mm. (av. 0.2992 mm.) ; cornicles, 0.187 to 0.221 mm. (av. 0.204 mm.) ; cauda, 0.136 to 0.153 mm. (av. 0.142 mm.) ; hind tarsus, 0.119 mm. Specimens taken by the author near Montebello, Los Angeles County, in December, 1916, and in Riverside from January to May, 1917, on Vicia faba seem to be somewhat different from the fore- going, yet are very nearly identical. Gillette considers that they might possibly be Aphis fdbae Scop., which may or may not be synonymous with Aphis euonomi Fabr. Superficially, the coloring seems to be the same, although on close observation it appears to be a very dark green in ground color, covered with a blackish tinge. The legs are colored as above, however. Specimens from Rumex appear to have considerably more brown in the ground color than the preceding varieties. Secondary sensoria are located as follows: III, 14 to 24 (av. 18) ; IV, 4 to 7 (av. 5) ; V, A SYNOPSIS OF THE APHIDIDAE 105 I to 4 (av. 3). Lateral abdominal tubercles could be found only on the first and seventh segments. Alate viviparous female. — Measurements: Body length, 1.768 to 2.142 mm. (av. 1.942 mm.) ; width of thorax, 0.782 to 1.054 mm. (av. 0.918 mm.) ; antennae total, 1.445 to 1.581 mm. (av. 1.496 mm.) ; III, 0.357 to 0.408 mm. (av. 0.394 mm.); IV, 0.255 to 0.323 mm. (av. 0.286 mm.) ; V, 0.204 to 0.255 mm. (av. 0.233 mm.) ; VI, base 0.136 to 0.153 mm. (av. 0.139 mm.) ; VI, spur 0.289 to 0.323 mm. (av. 0.306 mm.) ; cornicles, 0.187 to 0.255 mm. (av. 0.219 mm.) ; cauda, 0.136 to 0.17 mm. (av. 0.153 mm.) ; hind tarsus, 0.119 to 0.153 mm. (av. 0.147mm.). Apterous viviparous female. — Measurements : Body length, 2.278 to 2.448 mm. (av. 2.3403 mm.) ; antennae total, 1.309 to 1.598 mm. (av. 1.4382 mm.) ; III, 0.306 to 0.408 mm. (av. 0.3502 mm.) ; IV, 0.221 to 0.306 mm. (av. 0.2618 mm.) ; V, 0.206 to 0.255 mm. (av. 0.238 mm.) ; VI, base 0.119 to 0.17 mm. (av. 0.1394 mm.) ; VI, spur 0.289 to 0.34 mm. (av. 0.306 mm.) ; cauda, 0.17 to 0.204 mm. (av. 0.187 mm.) ; cornicle, 0.255 to 0.323 mm. (av. 0.289 mm.) ; hind tarsus, 0.153 to 0.17 mm. (av. 0.167 mm.). 122. Aphis frigidae Oestlund Oestlund, Geol. Nat. Hist. Snrv. Minn., vol. 14, p. 46, 1886 (orig. desc.). Davidson, Jour. Econ. Ent., vol. 7, p. 132, 1913 (desc. stem mother). Eecords. — Artemisia californica; Walnut Creek, Contra Costa County (David- son). In company with Macrosiphum artemisiae (Fonsc.) this species is found on sagebrush in the San Francisco Bay region. Wilson reports it from Oregon, so probably it is distributed along the coast from the bay north. In the course of observations in southern California during a period of two years the author has been unable to find any aphids infesting sagebrush. 123. Aphis gossypii Glover Figures 192, 193, 215 Glover, Pat. Off. Eec., p. 62, 1854 (orig. desc.). Clarke, Can. Ent., vol. 35, p. 250, 1903 (list). Essig, Pom. Jour. Ent., vol. 1, p. 47, 1909. Aphis citri Ashmead (desc.). Essig, Pom. Jour. Ent., vol. 3, p. 590, 1911 (desc.). Cook, Mon. Bull. Cal. Comm. Hort., vol. 1, p. 65, 1912 (list). Games, Mon. Bull. Cal. Comm. Hort., vol. 1, p. 398, 1912 (list). Weldon, Mon. Bull. Cal. Comm. Hort., vol. 2, p. 597, 1913 (list). Davidson, Mon. Bull. Cal. Comm. Hort., vol. 6, p. 65, 1917 (note). 106 MISCELLANEOUS STUDIES Records. — Cucumis spp. ; Newcastle, Placer County, Watsonville, Santa Cruz County (Clarke); Imperial County (Weldon) ; San Diego County, June, 1916: Cucurbita spp.; Alpine, San Diego County, June, 1916: Citrus spp.; Santa Paula, Claremont (Essig), Acampo, San Joaquin County (Games), San Diego, March, 1916 (E. E. McLean); Whittier, May, 1917: Heracleum lanatum; Berkeley, March, 1915 (Essig): Begonia; Stanford University, February, 1912 (Morrison), Biverside, January, 1917; Punica granatum, Stanford University, April, 1911 (Davidson): Helianthus; Santa Ysabel, San Diego County, May, 1916: Pcrsea gratissima; Avondale, San Diego County, August, 1916; Chrysanthemum; Ontario, January, 1917; Esclischoltzia calif omica ; Ontario, January, 1917: Anthemis spp.; Pasadena, April, 1917 (E. E. Campbell): Pyrus spp.; Santa Cruz County (Volck), Nevada County (Norton). The melon or cotton aphis is distributed throughout the state and is found on a large number of host plants. On melons it is often a considerable pest, particularly in the Imperial Valley. In the apple sections of Santa Cruz and Nevada counties it often becomes abundant enough upon the young trees to cause considerable damage, according to County Horticultural Commissioners Volck and Norton. In San Diego County the author found an infestation on young avocado trees which was very severe. Oftentimes it becomes quite abundant in nurseries and greenhouses. 124. Aphis hederae Kalt. Kaltenbach, Monog. d. Pflanzenlause, p. 89, 1843 (orig. dese.). Davidson, Jour. Econ. Ent., vol. 2, p. 302, 1909. A. rumicis Linn, (list in part). Essig, Pom. Jour. Ent., vol. 2, p. 335, 1910 (desc.). Davidson, Jour. Econ. Ent., vol. 3, p. 376, 1910. A. rumicis Linn. (list). Records. — Hedera helix; Stanford University (Davidson), March, 1912 (Mor- rison) ; Claremont, Los Angeles County (Essig) ; San Jose, May, 1911 (Davidson, Morrison); Oakland, November, 1916 (Davidson); Berkeley, April, 1915; Lemon Grove, San Diego County, March, 1916; Eiverside, October, 1916: Chcnopodium sp., Walnut Creek, Contra Costa County, May, 1915 (Davidson). Throughout the San Francisco Bay region and southern Califor- nia a small dark brown to black aphid is often found in colonies on the tender shoots of English ivy. Essig described it as Aphis hederae Kalt., but later it was believed to be Aphis rumicis Linn. (A. euonomi Fabr.). However, a careful study of a large series of specimens of this aphid from ivy and of A. euonomi Fabr. from a number of dif- ferent host plants has convinced the author that they are distinct. Gillette is of the same opinion. Consequently the species from ivy in California is Aphis hederae Kalt. In the author's collection there is a specimen from Chenopodium sp. taken by Davidson that appears to be the same species. The most noticeable difference between this A SYNOPSIS OF THE APH1DIDAE 107 and Aphis euonomi Fabr. is in the length of the cornicles, which are very much longer in this species. Measurements of specimens of the alates from Oakland, Walnut Creek, San Jose, and Riverside are herewith given: Measurements: Body length, 1.411 to 1.768 mm. (av. 1.621 mm.) ; width of thorax, 0.714 to 0.782 mm. (av. 0.748 mm.) ; antennae total, 1.411 to 1.549 mm. (av. 1.499 mm.) ; III, 0.323 to 0.391 mm. (av. 0.365 mm.) ; IV, 0.272 to 0.323 mm. (av. 0.2914 mm.) ; V, 0.221 to 0.272 mm. (av. 0.2518 mm.) ; VI, base 0.119 to 0.136 mm. (av. 0.311 mm.) ; VI, spur 0.306 to 0.34 mm. (av. 0.323 mm.) ; cauda, 0.136 mm.; cornicle, 0.306 to 0.34 mm. (av. 0.3252 mm.) ; third tarsus, 0.119 to 0.136 mm. (av. 0.1237 mm.). It will be seen that the cornicles are considerably more than twice as long as the hind tarsi, in some cases practically three times, while in A. euonomi Fabr., they are scarcely twice as long as the hind tarsi. In A. euonomi Fabr. the hind tarsi are longer than the base of VI, while the cornicles are shorter than VI spur. In A. hedera-e Kalt. VI spur and the cornicles are subequal or on the average the cornicles are very slightly longer, while VI base and the hind tarsi are also sub- equal, the tarsi being shorter on the average. The secondary sensoria in A. hedcrae Kalt. are small, irregular in size, and are scattered more or less irregularly along III but in a fairly even row along IV and V. They appear very much the same as in A. euonomi Fabr. There are from thirteen to twenty on III, seventeen being the average; from five to nine on IV, seven and eight being the usual number; and usually one on V, although in a few cases there appear to be none. 125. Aphis heraclei Co wen Cowen, Hemip. Colo., p. 120, 1895 (orig. dese.). Essig, Univ. Calif. Publ. Entom., vol. 1, p. 339, 1917 (list). Record. — Heracleum montezzamum ; Berkeley (Essig). Recently Essig reported having taken this species on Heracleum in Berkeley. The author has specimens from Essig, although he has never collected it himself. This is the only report of the species since Cowen 's original report and description. 126. Aphis houghtonensis Troop? Troop, Ent. News, vol. 17, p. 59, 1906 (orig. desc.). Davidson, Jour. Econ. Ent., vol. 7, p. 132, 1914 (list). Eecord. — Ribes sanguineum; Contra Costa County (Davidson). 108 MISCELLANEOUS STUDIES Davidson reported a species of Aphis infesting the terminal leaves of wild currant in the canyons of Contra Costa County. He identified it provisionally as this species as he was uncertain. The author is unacquainted with it. 127. Aphis lithospermi Wilson Wilson, Trans. Am. Ent. Soc., vol. 41, p. 100, 1915 (orig. desc.). Record. — Lithospermum pilosum; California (Wilson). There is no definite record of this species in California, but it is listed here because Wilson added it to a list of the California Aphi- didae submitted to him by the author. 128. Aphis maidis Fitch Figures 216 to 218 Fitch, Insects N. Y., vol. 1, p. 318, 1855 (orig. desc.). Clarke, Can. Ent., vol. 35, p. 251, 1903 (list). Davidson, Jour. Econ. Ent., vol. 5, p. 408, 1912 (list). Records. — Corn; Watsonville, Berkeley (Clarke); San Jose (Davidson); Lake- side, San Diego County, April, 1916; Chula Vista, San Diego County, August, 1916: sorghum; Julian, San Diego County, August, 1916 (H. M. Armitage) ; Corona, Eiverside County, September, 1916. Only occasionally is this corn aphis found in California, where it infests the ears and tassels and leaves of corn and some of the sor- ghums. Never has it been observed as injurious as is sometimes reported from the middle western states. 129. Aphis malifoliae Fitch Figures 248 to 250 Fitch, Trans. N. Y. State Agr. Soc., vol. 5, p. 14, 1854 (orig. desc.). Clarke, Can. Ent., vol. 35, p. 252, 1903. Aphis sorbi Ka.lt. (list). Games, Mon. Bull. Cal. Comm. Hort., vol. 1, p. 400, 1912. A. sorbi Kalt. (list). Weldon, Mon. Bull. Cal. Comm. Hort., vol. 3, p. 188, 1914. A. sorbi Kalt. (list). Baker and Turner, Jour. Agr. Ees., vol. 7, pp. 321-343, 1916 (complete account). • Records. — Pyrus mdlus, P. communis; Central and northern California; Orange County, May, 1917. A SYNOPSIS OF THE APHIDIDAE 109 This is one of the most injurious of our California species of Aphis, being found in practically all of the apple-growing regions of the state, and in most of them necessitating some control measures. It has been reported on apple and pear in the following counties : Hum- boldt, Orange, Placer, Sacramento, Santa Clara, Shasta, Tehama, Nevada, Inyo, Santa Cruz, and Alameda. Probably it is present wherever apples are grown, with the exception of the southern Cali- fornia districts where it has never been observed. The apple is the primary host, and only occasionally has it been taken on pear. In May, 1917, Roy K. Bishop found it in Orange County, this being the first report of it south of the Tehachapi. The life history of this Aphis in California is as follows : In the fall and early winter the eggs are laid in the crotches of the twigs. These hatch in the following spring, the exact time depending upon the weather conditions but it is usually as the buds are begin- ning to show green, or as they are beginning to open. The author has observed the young stem mothers on the young buds of the apple in the latter part of March, although he has never been able to find the eggs, either those yet unhatched or those from which the stem mothers have already hatched. Horticultural Commissioner Weatherby of Humboldt County writes that he has found the eggs hatching as early as February 24. He goes on to state that the eggs of Aphis pomi De Geer do not hatch until considerably later. Horticultural Com- missioner Norton of Nevada County has made the following observa- tions : The eggs of Aphis sorbi [malifoliae] are laid on the buds, or sometimes on the spurs close to the buds. At first they are hard to see as they are small and light green, but later they turn to a shiny black, when they can be more readily detected. The young aphids hatch as soon as the buds begin to swell, which time varies with the season. I have found them sometimes as early as the first of March and at other times as late as the middle of April. The stem mothers feed upon the plant juices through the buds, sometimes appearing on the outer surface of the buds and at other times crawling down into the unfolding leaves, as is the case with Aphis pomi De Geer. In a few weeks these are mature and begin to deposit live young. All of this second generation are apterous females so far as the author has been able to observe. On April 12, 1915, he found several colonies of these aphids in the apple orchard at Stanford University, each colony consisting of a stem mother and several young apterous viviparous females. These females mature in a few weeks 110 MISCELLANEOUS STUDIES and a third generation is begun. The most usual place to find the second and third generations is in the curled terminal leaves of the plant. These leaves are curled very similarly to those by the green apple aphis (Aphis pomi De Geer), but they are curled a great deal tighter. Winged females may appear in this third generation, but it is most usual to find them in the fourth. Horticultural Commis- sioner Volck of Santa Cruz County states that he has counted four generations before the summer migration. During May, 1915, the author collected many colonies of this Aphis and placed them in vials in the laboratory. Many others he attempted to colonize on some apple seedlings. Owing to various causes he was unable to make any successful colonizations on the apple trees, one of the chief causes being the destructive work of coccinellid larvae. Also during the first few days of June he was forced to be absent from town and on his return found that the gardener had "cleaned" the trees, for "they were all covered with lice." Until May 25 no alate females had been found, but on that date two appeared in the laboratory. On May 10, 1917, alates were found in Orange County. These alate females of the fourth (perhaps sometimes they appear in the third) generation migrate from the apple to some unknown host. At Stanford University in 1915 the migration began about the first of June and continued for some two or three weeks. On June 20 only two or three colonies, each consisting of but a very few individuals, were found where a month before there had been literally hundreds. The curled leaves still hung on the trees and in each curled leaf the moulted skins of the aphid were abundant. From Commissioner Norton of Nevada County comes the statement that he has known the migrants "to leave the trees as early as the middle of June, but the migration usually takes place between the first and the fifteenth of July. "Where they go I have never been able to find out, as I have never observed them on any other host plant. ' ' According to O. E. Bremner, Horticultural Commissioner of Sonoma County, the migration takes place there during June. This is the same as in Santa Clara County. In Orange County in 1917 the alate females appeared about the first of May. Migration began almost immediately and continued for two or three weeks. By May 24 only a very few aphids remained. This is fully a month earlier than migration takes place north of the Tehachapi. Incidentally the spring of 1917 was exceedingly cool and the summer very late. In normal years one would expect the aphids to leave the apple two or three weeks earlier. A SYNOPSIS OF THE APHIDIDAE 111 The summer host plant of this aphid is as yet unknown in Cali- fornia. During June, 1915, the author spent many hours in search of this host plant, but to no avail. He examined every kind of plant within two or three hundred yards of the apple orchard at Stanford University, but on none was he able to find any aphid that could pos- sibly be the summer form of Aphis malifoliae Fitch. Bremner reports having found isolated individuals on pigweed (Amaranthus retro- flex'us) in Sonoma County, but believes this to be accidental for he has never observed them to deposit young on this plant. Davidson writes that he has been able to colonize them in the laboratory on the leaves of plantain (Plantago spp.), in fact has been able to have them repro- duce in such large numbers as to kill the plants. On May 28, 1915, the author placed two alate females from apple leaves on each of two specimens of Plantago hirtella under bell jars in the laboratory at Stanford University. On returning to town on June 10 he found that the plants were in a dying condition, owing to a lack of proper care during his absence. However, he found many young lice present, all of which were alive and feeding. The adult alate females had already died. By June 16 the lice had moulted once, but then the plants were practically dead. He left Stanford within a few days not to return, so was unable to begin fresh experiments along this line. In his search for the alates in the field he was particularly careful to examine closely every plantain plant in the vicinity, but could find no trace of this aphid on them. Davidson also reports the same lack of success. Consequently, although the alates will deposit young on plaintain in the laboratory it cannot very well be the natural summer host in this state. Baker and Turner have proven that Plantago lanceolata is the summer host in Virginia. W. H. Britain has observed a definite migration to plaintain in Nova Scotia (Proc. Ent. Soc. Nova Scotia, vol. 1, pp. 16-30, 1915). Incidentally he has been able to breed it throughout the summer on apple. In Orange County, in the vicinity of the known infestations, the author was unable to find any plaintain whatsoever. On inquiring of Roy K. Bishop, the county horticultural commissioner, it was learned that plaintain is very scarce in that county, except very near to the coast, and that it is exceedingly doubt- ful if there is any in the vicinity of the known aphid infestations. The fall migrants begin to return to the apple some time during the fall and deposit living males and females. From Nevada County comes the report that the migrants return to the apple "between the twentieth of September and the first of October. ' ' Davidson has taken the oviparous females and the alate males on December 5 (1912) at 112 MISCELLANEOUS STUDIES Sebastopol; Morrison has taken the sexes at Stanford University on December 16 (1910) ; Moznette of the Oregon station has taken the migrants as late as the middle of November at Corvallis, Oregon. Consequently, egg laying probably occurs from the middle of October well into December in the various parts of California. Commissioner Norton states: "The first eggs that I have seen were observed about the fifteenth of October. However, they continue egg laying, in favorable years, well along into November. ' ' The injury caused by this aphid is done entirely in the spring of the year, before the summer migration, and consists in the curling of the terminal leaves. The colonies are found usually in the leaves surrounding a cluster of apples, and although most of the feeding is on the leaves themselves oftentimes they feed upon the fruit. In such a case the fruit (according to Weldon, ''Apple Growing in Cali- fornia," Mon. Bull. Cal. Comm. Hort., p. 86, 1915) "is injured to such an extent that it becomes stunted and not only fails to mature, but is distorted so badly that' the variety may not be recognizable. ' ' In Nevada County, Commissioner Norton reports: "The purple aphis unless controlled lessens the apple crop from ten to fifteen per cent. ' ' This is a higher percentage, undoubtedly, than is common throughout the state, but it shows how serious the pest may be. 130. Aphis marutae Oestlund Figures 293 to 299 Oestlund, Minn. Geol. Nat. Hist. Surv., vol. 14, p. 40, 1886 (orig. desc.). Eecords. — Silybum marianum; Grossmont, San Diego County, April, 1916: Centaurea melitensis; El Cajon, San Diego County, May, 1916. In April, 1916, the author observed a small aphid on milk thistle near Grossmont, San Diego County, and later on tacalote in the El Cajon Valley. It infested the smaller leaves, the leaf petioles, and the base of the flowers. Large numbers of ants were in attendance, but it was preyed upon extensively by the larvae and adults of Cocci- nella California. A considerable number of adults of Lysiphlebus testaceipes Cresson were reared from colonies of this aphid. Being unknown to the author specimens were sent to J. J. Davis and E. 0. Essig, both of whom determined the species to be Aphis marutae Oest- lund. Inasmuch as Oestlund 's descriptions are the only ones avail- able, a brief description is given below of specimens taken May 1, 1916, on Silybum marianum in San Diego County. A SYNOPSIS OF THE APHIDIDAE 113 Alate viviparous female. — Prevailing color pale to olive green. Head and prothorax dark olive green, thoracic lobes almost black. Abdomen pale green with marginal spots and patch on dorsum dusky. Legs pale except tarsi, apex of tibiae, and apical two-thirds of femora. Antennae, cornicles, and cauda dusky. Beak pale at base and dusky at tip. Head (fig. 293) not quite as long as broad, with a prominent tubercle at apex of front and small but distinct projections from head on inner side of first antennal segments. Antennae about same length as body or slightly longer or slightly shorter (figs. 294-295). Ill and the spur are about equal or III slightly longer, never shorter than spur. IV about one-half as long as III. V either shorter or equal to IV. VI shorter than V and about one-third as long as spur. I and II subequal and slightly shorter than VI. The usual primary sensoria are present on V and VI and the accessory sensoria on VI. Ill is tuberculate and IV is slightly so. IV has from two to six small, circular secondary sensoria and III from eleven to fifteen irregularly placed (fig. 294). The beak reaches considerably beyond the second coxae, in some cases almost to the third. The prothorax is without lateral tubercles. The wings are about twice as long as the body with normal venation. The stigmal vein is curved its entire length, the second branch of the cubitus arises about midway between the tip of the wing and the base of the first branch. The abdomen is without lateral tubercles in so far as the author can discern. The cornicles (fig. 299) are short and taper slightly from base to apex. They are about equal in length to the third tarsi, are almost one-half as wide at base as long, and about one-third as wide at apex as long. The cauda (fig. 298) is short and blunt (conical) and about two-thirds as long as the cornicles. The anal plate is half-moon-shaped and dusky at its distal edge. Measurements (of specimens in Canada balsam) : Body length, 0.918 to 1.02 mm. (av. 0.9248 mm.) ; width (thorax), 0.34 to 0.442 mm. (av. 0.4082 mm.) ; antennae total, 0.885 to 1.02 mm. (av. 0.942 mm.) ; I, 0.034 to 0.051 mm. (av. 0.037 mm.) ; II, 0.034 to 0.051 mm. (av. 0.048 mm.) ; III, 0.225 to 0.2975 mm. (av. 0.2601 mm.) ; IV, 0.117 to 0.17 mm. (av. 0.152 mm.) ; V, 0.1105 to 0.136 mm. (av. 0.1346 mm.) ; VI, 0.068 to 0.102 mm. (av. 0.0833 mm.) ; spur, 0.204 to 0.272 mm. (av. 0.2295 mm.) ; cornicles 0.0850 to 0.119 mm. (av. 0.0978 mm.) ; cauda, 0.0595 to 0.068 mm. (av. 0.0624 mm.) ; hind tarsi, 0.085 to 0.102 mm. (av. 0.0901 mm.) ; wing length, 1.921 to 1.955 mm. (av. 1.928 mm.) ; wing width, 0.661 mm.; wing expansion, 4.556 mm. 114 MISCELLANEOUS STUDIES Apterous viviparous female. — The apterae are quite similar to the alates except that the thorax is not dark, and that the second, third, and basal three-fourths of the fourth antennal segments are pale. There are no secondary sensoria (fig. 296) and no lateral tubercles on prothorax and abdomen (fig. 297). The individuals are slightly larger and the proportions of the antennal segments differ slightly from the alates. The measurements of specimens mounted in Canada balsam are as follows : Measurements: Body length, 1.00 to 1.04 mm. (av. 1.026 mm.); width (abdomen), 0.595 to 0.629 mm. (av. 0.6064 mm.) ; antennae total, 0.561 to 0.697 mm. (av. 0.6151 mm.) ; III, 0.102 to 0.136 mm. (av. 0.1218 mm.); IV, 0.0765 to 0.1105 mm. (av. 0.0906 mm.); V, 0.068 to 0.085 mm. (av. 0.0765 mm.) ; VI, 0.595 to 0.0765 mm. (av. 0.068 mm.) ; spur, 0.1615 to 0.1785 mm. (av. 0.1711 mm.) ; cornicles, 0.0765 to 0.11 mm. (av. 0.0935 mm.) ; cauda, 0.0595 mm.; hind tarsi, 0.102 mm. (Description from nine specimens of apterae). It will be noticed that in the apterae the antennae are but about two-thirds as long as the body, while in the alates they are almost as long as the body. Furthermore, in the apterae the spur of the sixth antennal segment is always longer than III while in the alates it is equal to III at the most, and in many cases shorter. 131. Aphis medicaginis Koch Figure 189 Koch, Die Pflanzenlause, p. 94, 1854 (orig. desc.). Davidson, Jour. Econ. Ent., vol. 2, p. 302, 1909 (list). Davidson, Jour. Econ. Ent., vol. 3, p. 376, 1910 (list). Essig, Pom. Jour. Ent., vol. 3, p. 527, 1911 (dese.). Records. — Medicago hispida; Stanford University (Davidson), April, 1914 (R W. Haegele) : Astragalus leucopsis; Nordhoff, Ventura County (Essig) : Vicia faba, lima bean, Pasadena (E. E. Campbell). This small dark Aphis has been found occasionally in California, particularly on alfalfa and beans. Such other plants as loco weed, licorice, sagebrush, locust, and others are said to be hosts. The author has never collected it himself, but has had access to specimens taken by Essig, Haegele, and Campbell. Davidson has reared the braconid fly, Lysipheebus testaceipes Cresson, from this aphid. A SYNOPSIS OF THE APHIDIDAE 115 132. Aphis middletonii Thomas Figures 219, 220 Thomas, 8th Ann. Kep. 111. St. Ent., p. 99, 1879 (orig. desc.). Recards. — Amaranthus retro flexus ; Santa Paula, August, 1911 (Essig) : Ban- unculus calif ornicus; Julian, San Diego County, June, 1916: Hemizonia rudis; Stanford University, 1916 (Ferris) : Helianthus annuus; Kiverside, September, 1916. In the fall of the year this species is rather common on the roots of various plants in California. The individuals are small green aphids, covered with a slight pulverulence. They are very similar to Aphis maidis-radicis Forbes, with which they have often been con- fused, and differ particularly in the presence of secondary sensoria on the fourth antennal segment of the apterae. Below are a few descriptive notes taken from specimens mounted in balsam, collected in 1916 in Julian and Riverside, and in 1911 near Santa Paula: Alate viviparous female. — Greenish, pruinose. Head, antennae, thorax, marginal spots on abdomen, cornicles, cauda, apical one-half femora, apices tibiae, tarsi, and apex of beak, black. Antennae reach to the base of the second abdominal segment; III being the longest segment, followed by VI spur. IV and V are subequal, VI base slightly shorter. The usual primary and accessory sensoria are pres- ent. Secondary sensoria occur on III and IV (fig. 220). There are nine to twelve on III, and one to four on IV. The average numbers are eight and two respectively. The beak reaches to the third coxae. Prominent lateral tubercles are present on the first and seventh abdominal segments, as well as on the prothorax. The cornicles are short and taper slightly toward the apex. They are subequal in length to the hind tarsi, and very slightly larger than the cauda. The wings are normal, with the second branch of the third discoidal arising nearer to the apex of the wing than to the base of the first branch. Measurements: Body length, 1.65 to 1.7 mm. (av. 1.674 mm.); width of thorax, 0.561 mm. ; antennae total, 0.816 to 0.918 mm. (av. 0.884 mm.) ; III, 0.204 to 0.255 mm. (av. 0.2338 mm.) ; IV, 0.11 to 0.119 mm. (av. 0.1169 mm.) ; V, 0.11 to 0.136 mm. (av. 0.1275 mm.) ; VI, base 0.085 to 0.102 mm. (av. 0.0986 mm.) ; VI, spur 0.204 mm.; cauda, 0.102 mm.; cornicles, 0.1275 to 0.136 mm. (av. 0.1332 mm.) ; hind tarsus, 0.119 to 0.136 mm. (av. 0.1303 mm.) ; wing length, 1.904 to 2.38 mm. (av. 2.159 mm.) ; width, 0.731 to 0.85 mm. (av. 0.815 mm.) ; expansion, 4.3 to 5.1 mm. (av. 4.717 mm.). 116 MISCELLANEOUS STUDIES Apterous viviparous female. — These are very similar to the alate females, only slightly larger. The antennae are dusky throughout except the base of III. They reach to the base of the first abdominal segment. Ill is the longest segment. VI spur is next, being about two-thirds as long. IV, V, and VI base are subequal, with V some- what shorter than the others. The usual primary and accessory sen- soria are present on V and VI. Ill has two or three small secondary sensoria located in the apical one-third of the segment. IV has from one to three in the apical one-half. The prothorax and the first and seventh abdominal segments each have a pair of conspicuous lateral tubercles. The cornicles are black and somewhat larger than in the alates, being slightly longer than the hind tarsi. The cauda is a little shorter than the hind tarsi. Measurements: Body length, 1.632 to 1.785 mm. (av. 1.708 mm.) ; width of thorax, 0.748 to 0.85 mm. (av. 0.799 mm.) ; antennae total, 0.867 to 0.969 mm. (av. 0.9265 mm.) ; III, 0.2465 to 0.289 mm. (av. 0.2635 mm.) ; IV, 0.102 to 0.136 mm. (av. 0.119 mm.) ; V, 0.102 to 0.119 mm. (av. 0.1105 mm.) ; VI, base 0.119 mm.; VI, spur 0.1615 to 0.187 mm. (av. 0.17 mm.) ; cornicles, 0.153 to 0.17 mm. (av. 0.1615 mm.) ; cauda 0.119 mm. ; hind tarsus, 0.136 mm. 133. Aphis mori Clarke Clarke, Can. Ent., vol. 35, p. 251, 1903 (orig. desc.). Record. — Morus sp., Berkeley (Clarke). This is a rather doubtful species, described by Clarke from speci- mens taken on mulberry in Berkeley. Since the original description it has never again been observed. 134. Aphis neomexicana Ckll. var. pacifica Dvdn. Figures 300, 302 Davidson, Jour. Econ. Ent., vol. 10, p. 293, 1917 (orig. desc. var.). Records. — Eibes rubrum; Walnut Creek, Contra Costa County, and San Jose (Davidson). Davidson described this variety from specimens found curling the leaves of cultivated red currant in Walnut Creek in June, 1915. What he takes to be the same species he had already collected in San Jose in May, 1912. The author has specimens from him, but has never collected any himself. 117 135. Aphis nerii Fonsc. Figures 221, 222 Boyer de Fonscolombe, Ann. Ent. Soc. France, vol. 10, p. 167, 1841 (orig. desc.). Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1910 (list). Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1910. A. lutescens Monell (list). Davidson, Pom. Jour. Ent., vol. 3, p. 399, 1911. A. lutescens Monell (list). Essig, Pom. Jour. Ent., vol. 3, p. 401, 1911. A. lutescens Monell (desc.). Essig, Pom. Jour. Ent., vol. 3, p. 530, 1911 (dese.) Branigan, Mon. Bull. Cal. Comm. Hort., vol. 4, p. 53, 1915 (list). Eecords. — Asclepias mexicana; Stanford University (Davidson) ; Stanford University, October, 1910 (Morrison) ; Penryn, Placer County (Davidson) ; south- ern California (Essig); Berkeley, July to September, 1915: Nerium oleander; southern California (Essig) ; Sacramento (Branigan) ; Berkeley, August to Decem- ber, 1915 j San Diego, 1916. In the late spring, summer, and early fall milkweeds throughout the state are often seen to be infested with a bright yellow and black aphid. In the fall and early winter this same species is found infest- ing oleanders. Where oleanders are present but no milkweeds this aphid can be found from spring until winter on the oleander, as observed during 1916 in San Diego. Heretofore the species on oleander and milkweed have been con- sidered as distinct, the former being called A. lutesc&ns Monell, the latter A. nerii Fonsc. According to a note from J. J. Davis the species on milkweed could not be A. lutescem Monell. Following are extracts from his letters concerning this point : I am wondering whether you have ever found winged specimens on Asclepias that do not bear the black markings at the base of the cornicles. All the speci- mens that I have collected and which Mr. Monell has collected in recent years have these black markings at the base of the cornicles in the winged forms. However, in referring to an old note from Mr. Monell, he says that it would seem hardly possible that he could have missed these dark spots if they had been present in the specimens from which he drew his description for Aphis lutescens, and re- marks further that he is not sure that he has ever seen A. lutescens alive since he first described it. I am wondering if lutescens is not really asclepiadis of Pass- erini and whether our other common species on Asclepias and Nerium is not nerii Fonsc. During the summer of 1915 the author found this species on Asclepias in the Botannical Gardens at the University of California. During July and August it was quite abundant; in fact, it was especially thick on the stems and undersides of the leaves and blossoms. However, in the latter part of August it seemed to be getting less 118 MISCELLANEOUS STUDIES and less numerous. No sign of parasites was present, and the pre- daceous enemies were not more abundant than usual, so a search for the cause was made. Within fifty feet of the milkweed plants several oleanders were found and on them was noticed a large yellow species of Aphis. This supposedly was Aphis nerii Fonsc. In the laboratory the author could find no structural difference whatsoever between this species and the one on Asclepias, so he continued to watch them care- fully on the hosts. As the days passed the Asclepias became freer and freer of the infestation, while the Nerium became more and more heavily infested. This continued through September and into October, by which time the Asclepias had died down and incidentally no aphids were left. The Nerium was very heavily infested then. This was taken as a good proof that these were the same species. Later Essig told the author that the summer before (1914) he had made transfer tests in the laboratory of specimens from Asclepias to Nerium and that they thrived there and bred well. This fact and the observations above mentioned were noted in a letter to Davis. Following is his answer : I have your letter relative to Aphis asclepiadis and nerii, and am interested in your observations. In 1'914, Theobald described a species under the name of Aphis nigrepes, which he now places as a variety of asclepiadis. He considers nerii as distinct from asclepiadis because the latter lacks the black patches at the base of the cornicles. Passerini's asclepiadis is entirely different from Fitch's Aphis asclepiadis. Fitch's name has priority for, as you will notice, it was described in 1851. This being the case, Passerini's name will have to fall and be replaced by Aphis lutescens of Monell, which according to Mr. Monell 's data does not bear the black patches around the base of the cornicles. This would seem to indicate that the California species on Asclepias is Aphis nerii Fonsc. and not A. lutescens Monell, as brought out by Essig 's experiment and by the author's observation. Consequently this Californian species is Aphis nerii Fonsc., with Asclepias for its summer host and Nerium for the winter host. 136. Aphis oenotherae Oestlund Oestlund, Minn. Geol. Nat. Hist. Surv., Bull. 4, p. 62, 1887 (orig. desc.;. Clarke, Can. Ent., vol. 35, p. 252, 1903 (list). Record. — Oenoihera bectiana; Epilobium sp., Berkeley (Clarke). In 1903 Clarke recorded finding this species on primrose and willow herb in Berkeley. Since then it has not been observed in Cali- fornia. The author has had the opportunity to study specimens from Minnesota, taken by A. C. Maxson. A SYNOPSIS OF THE APHIDIDAE 119 137. Aphis oregonensis Wilson Wilson, Trans. Am. Ent. Soc., vol. 41, p. 92, 1915 (orig. desc.). Record. — Artemisia tridentata, California (Wilson). Wilson stated to the author that he had taken this species in California although he gave no locality or date records. On the strength of his statement it is included among the California aphids. The author has never seen specimens of it. 138. Aphis persicae-niger Smith Figures 223, 224 Smith, Ent. Am., p. 101, 1890 (orig. desc.). Clarke, Can. Ent., vol. 35, p. 252, 1903 (list). Gillette, Jour. Econ. Ent., vol. 1, p. 308, 1908 (desc.). Weeks, Mon. Bull. Cal. Comm. Hort., vol. 1, p. 244, 1912 (list). Jones, Mon. Bull. Cal. Comm. Hort., vol. 1, p. 318, 1912 (list). Games, Mon. Bull. Cal. Comm. Hort., vol. 1, p. 399, 1912 (list). Wood, Mon. Bull. Cal. Comm. Hort., vol. 2, p. 570, 1913 (list). Records. — Prunits spp. ; throughout California. This species is ordinarily found infesting the tender twigs and leaves of peach in the spring and early summer. Occasionally it is found on nectarine, plum, and cherry. There are two records of its occurrence on cherry known to the author; one in San Jose in May, 1912, by Davidson, and one in El Cajon, San Diego County, in May, 1916, by the author. Definite reports of its presence on peach come from Los Angeles, Placer, Riverside, San Benito, San Bernardino, San Diego, Santa Clara, and Tehama counties. In May, 1916, the author observed it doing considerable damage to a young peach orchard in the El Cajon Valley, San Diego County. Many of the twigs and some of the larger branches were killed back for several inches, due to the ravages of this insect. The Hippodamia ladybird and the larvae of a syrphid fly were abundant and devouring vast numbers of the aphids. However, it is not often that this appears abundant enough to cause any great amount of damage. Its life history, although not thoroughly worked out, is interesting. The following brief summary is from Essig:17 The insect winters over on the roots of the peach trees, where it may also be found in the summer. The first aphids appear above ground very early in the 17 Essig, E. O., Beneficial and injurious insects of California; ed. 2. Suppl. Mon. Bull. Cal. Comm. Hort., vol. 4, pp. 91-92, 1915. 120 MISCELLANEOUS STUDIES spring and begin attacking the tender leaflets, shoots and suckers, usually those at the base of the tree or nearest the ground. These first plant lice are all wing- less. As soon as the buds, young fruit, and leaves appear they are promptly attacked, the entire crop often being entirely ruined. The leaves are curled and weakened, while the young fruit is so distorted as to be killed or rendered unfit for market. During the months of April and May winged migratory females appear, which start colonies on other trees. The work continues until about the middle of July, when most of the lice leave the tops and again go to the roots. 139. Aphis pomi De Geer Figures 225 to 227 De Geer, Memoires, vol. 3, p. 173, 1773 (orig. desc.). Davidson, Jour. Econ. Ent., vol. 2, p. 301, 1909 (list). Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1911 (list). Aphis mali Fabr. Weatherby, Mon. Bull. Cal. Comm. Hort., vol. 1, p. 318, 1912 (list). Games, Mon. Bull. Cal. Comin. Hort., vol. 1, p. 399, 1912 (list). Branigan, Mon. Bull. Cal. Comm. Hort., vol. 4, p. 285, 1915 (list). Hurdley, Mon. Bull. Cal. Comm. Hort., vol. 4, p. 445, 1915 (list). Baker and Turner, Jour. Agr. Res., vol. 5, pp. 955-995, 1916 (complete account). Eecords. — Pyrus mains; Crataegus oxycantha; Catalpa sp. ; California. In California this species has been reported on apple and haw- thorn (Crataegus sp.) at Stanford University by Davidson and Morrison; in Humboldt County by Weatherby; at Santa Rosa by Games; and by others in Orange, Placer, Sonoma, Santa Cruz, San Bernardino, and Monterey counties. Horticultural Commissioner Armitage states that it has never been found in San Diego County, and Horticultural Commissioner Norton writes that it is unknown in Nevada County. These are the only two of the apple growing regions of the state in which it is not known. The author has found it at Stanford University on apple, catalpa, pear, and hawthorn, and at Marysville on catalpa. Gillette lists loquat, quince, and flowering crab as additional hosts. It seems to prefer the apple to other hosts, and it is on the apple that its greatest injury is done. Gillette states : ' ' Among the apple trees it has its preference. Missouri Pippin seems to be its first choice, while Rome Beauty, Black Twig, Ben Davis, and a few others are second choice, and the Northern Spy is scarcely attacked." The fact that the Northern Spy is almost immune is interesting in that this variety is also quite immune to the devastations of the woolly aphis (Eriosoma lanigera Hausman). The life history of this aphid is quite similar to that of many other species, and is as follows : A SYNOPSIS OF THE APHIDIDAE 121 The eggs are laid in the fall of the year, probably during the latter part of October, throughout November, and on into December. They are laid for the most part on the smooth bark of the suckers and water sprouts of the newer shoots. The author has found them in the crotches of the twigs and stems where the bark is rougher, but this is not the usual place. These eggs hatch in the spring about the time the buds begin to show green. In California this is usually during March, although some seasons it is as early as the middle of February, depending entirely upon the weather conditions. These stem-mothers at first feed on the young buds, until the latter have opened enough to allow the aphids to crawl down into the curled leaves. Here they feed for two or three weeks, when they mature and begin depositing living young. This second generation consists chiefly of apterous females, which mature in from two to four weeks and in turn produce young. The following generations are in large part alate females which migrate to other trees and there form new colonies. The alates are most common at Stanford University during the latter part of May and during the month of June. After June they seem to lessen in number, perhaps due to the predaceous and parasitic enemies. The first alates that the author has found in the spring were taken at Stanford University on April 13, 1914. In the fall, often as early as October, sexual males and females begin to appear, the males being apterous, the females alate. These mate and very soon the female lays its eggs. Egg laying begins usually in the latter part of October, just as the leaves are beginning to fall, and continues into December after the trees are bare. These eggs hatch in the spring into stem mothers, and the life cycle is completed. 140. Aphis prunorum Dobr. Figures 228 to 230 Dobrowljansky, Zur Biol. d. Blattlause d. Abstbaume u. Biirenstaucher, 1913 (orig. desc.). Patch, Maine Agr. Exp. Sta., Bull. 233, p. 262, 1914 (desc. note). Records. — Prunus domestica; Walnut Creek (Davidson) ; San Francisco, April, 1915 (Shinji). A species of Aphis, supposed to be this species, has been taken on prune and plum in the San Francisco Bay region. It agrees very well with Dr. Patch's description listed. However, it may prove to be synonymous with Siphocoryne nymphaeae (Linn.). 122 MISCELLANEOUS STUDIES 141. Aphis pseudobrassicae Davis Figure 231 Davis, Can. Ent., vol. 46, p. 231, 1914 (orig. desc.). Records. — Brassica spp. ; Walnut Creek (Davidson), San Diego, Riverside: Baphanus sp., Riverside, September, 1916, June, 1917 : Matthiola annua, Riverside, February to May, 1917. Oftentimes in the spring this false cabbage aphis is found in large colonies on radish, mustard, and so forth. Davidson has taken it in the San Francisco Bay region, and the author throughout southern California. The first few times that it was observed by the author colonies of Aphis brassicae Linn, were also abundant. This led the author to doubt its validity, and to undertake some breeding experi- ments. In February, 1917, two colonies were started, each from one alate female. They were followed through three generations, with the result that all the individuals proved to be this species. At the same time a colony of Aphis brassicae Linn, was started from one alate. All the progeny of this individual proved to be the same. A. pseudo- brassicae Davis differs from A. brass-icae Linn, in the following major points : A. pseudobrassicae Davis: A. brassicae Linn.: Apterae not pulverulent. Apterae pulverulent. Cornicles of apterae longer than hind Cornicles of apterae shorter than tarsi. hind tarsi. IV of alates with sensoria. IV of alates without sensoria. 142. Aphis ramona Swain Figures 232 to 235 Swain, Trans. Am. Ent. Soc., vol. 44, p. 14, 1918 (orig. desc.). Records. — Ramona stachyoides; Nordhoff and Santa Paula, Ventura County (Swain). This species has been taken twice in Ventura County by Essig. It was described by the author from the specimens taken by Essig on black sage. 143. Aphis rubiphila Patch Patch, Maine Agr. Exp. Sta., Bull. 233, p. 269, 1914 (orig. desc.). Records. — Rub us spp.; San Jose, May, 1916 (Davidson). In the summer of 1916 Davidson found a species of Aphis infesting loganberries and blackberries in San Jose, which was determined by Dr. Patch as A. rubiphila Patch. Essig believes this to be a synonym A SYNOPSIS OF THE APHIDIDAE 123 of A. gossypii Glover, but as the author has not had an opportunity to study specimens he believes it best to recognize it as a distinct species at present. 144. Aphis salicicola Thomas Figures 188, 238, 237 Thomas, 111. Lab. Nat. Hist., Bull. 2, p. 8, 1879 (orig. desc.). Williams, Univ. Neb. Studies, vol. 10, p. 139, 1910 (desc.). Davidson, Jour. Econ. Ent., vol. 5, p. 408, 1912 (list). Records. — Salix laevigata; Berkeley, June, 1915: Salix, sp. ; San Jose (David- son). This is an uncommon species, found in the San Francisco Bay region on willow. The individuals are found in large colonies on the terminal shoots and leaves. These colonies consist in large part of apterae, there being but a very few alates. The species is quite easily recognized by the long cornicles and by the very short second branch of the third discoidal vein. 145. Aphis sambucifoliae Fitch Figure 240 Fitch, Cat. Homop. N. Y., p. 66, 185 (orig. desc.). Sanborn, Kan. Univ. Sci. Bull. 3, p. 52, 1904 (dese.). Records. — Sambucus glauca; Oakland, April, 1915 (Essig) ; Berkeley, July, 1915. In 1915 this species was taken twice, once by Essig in Oakland and once by the author in Berkeley. This medium-sized black aphid occurs in large colonies on the tender shoots and flower heads of the common elderberry. In southern California the author has examined hundreds of elderberry trees for this form, but has never found it. Only once has he found any aphid on elderberry in the south, and these proved to be Rhopalosiphum persioae (Sulz.). 146. Aphis senecio Swain Figures 2, 4, 6, 241 to 245 Davidson, Jour. Econ. Ent., vol. 2, p. 302, 1909. Aphis sp. (list). Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1910. A. bakeri Cowen (list). Davidson, Jour. Econ. Ent., vol. 7, p. 133, 1914. A. bakeri Cowen (list). Swain, Trans. Am. Ent. Soc., vol. 44, p. 16, 1918. Records. — Abutilon sp. ; Stanford University, February, 1915: Ambrosia psilostachya; Berkeley, 1915 (Essig): Amsinckia spp. ; Stanford University, 1909 (Davidson), 1912 (Morrison); Berkeley, 1915 (Essig): Anthemis spp.; San 124 MISCELLANEOUS STUDIES Francisco Bay region, 1914 (Davidson) ; Pasadena, May, 1917 (Boy E. Camp- bell): Artemisia spp.; San Francisco Bay region, 1914 (Davidson); Berkeley, 1915 (Essig) : Aster sp. ; San Diego, January, 1916; Ontario, January, 1917: Bacchari* pilularis ; Berkeley, 1915 (Essig), Stanford University, 1916 (Ferris): Calendula officinale; Berkeley, 1915 (Essig); San Diego, March, 1916; Riverside and Orange, February, 1917: Chrysanthemum sp. ; Berkeley, 1914 (Essig); Octo- ber, 1915; Menlo Park, San Mateo County, March, 1915; San Diego, January, 1916; La Jolla, February, 1916; Ontario, January, 1917: Cytisus proliferus; Berkeley, 1915 (Essig): Gnapholium sp. ; Walnut Creek, 1914 (Davidson): Grin- delia cuneifolia; Walnut Creek, 1915 (Davidson): Hclianthus annuus; San Frau- cisco Bay region, 1914 (Davidson): Eumex sp. ; Stanford University, March, 1915: Salix sp. ; Berkeley, 1915 (Essig): Senecio spp.; Stanford University, 1909, 1910, 1914 (Davidson) ; Santa Paula, 1911 (Essig) ; Palo Alto, February, 1915. This is a very common species throughout California, occurring on many host plants, particularly the Compositae. It is found most commonly in the early spring on asters, marigolds, and chrysanthe- mums in southern California, and on German ivy and amsinckia in the San Francisco Bay region. For sometime it was believed to be Aphis bakeri Cowen, but its variety of host plants so widely different from those of bakeri, led to its being identified as a distinct species. It is one of the most common in the state, as a glance at the collection records will show. 147. Aphis setariae Thomas ' Figures 246, 247 Thomas, 111. Lab. Nat. Hist., Bull. 2, p. 5, 1878 (orig. desc.). Williams, Univ. Neb. Studies, vol. 10, p. 141, 1910 (desc.). Record. — Prunus domestica; San Francisco Bay region (Davidson). In some parts of the country this plum louse becomes abundant enough to cause serious damage, but it has never been observed to be so in California. Davidson writes that he has found it sparingly a few times in the San Francisco Bay region. The author has never collected it, but has had access to specimens from Morrison, taken in Indiana. 148. Aphis spiraecola Patch Patch, Maine Agr. Exp. Sta,, Bull. 233, p. 270, 1914 (orig. desc.). Records. — Spiraea spp.; Stanford University, 1912 (Morrison); Walnut Creek, Contra Costa County, 1916 (Davidson). In the San Francisco Bay region there is a small aphid very similar to Aphis pami De Greer found attacking meadowsweet. David- son and Morrison, who have both observed it, believe it to be this species. The following brief descriptive notes are from alate females A SYNOPSIS OF THE APHIDIDAE 125 taken by Dr. Patch on cultivated spiraea in Orono, Maine. These notes are included here as there is no adequate description of this species, the only ones18 being very meager notes indeed . Alate viviparous females. — Body rather long and narrow, head normal with no antennal tubercles. Antennae shorter than body, reaching to about the base of the fourth abdominal segment. VI spur the longest segment, followed by III, which is about two-thirds as long. Following III are IV, V, and VI base. The usual primary sensoria are present on V and VI, and the accessory sensoria on VI. The secondary sensoria are fairly large and circular. There are six or seven in an even line along the whole length of III. On IV there may be one or two near the middle, or there may be none. Prominent lateral tubercles are present on the prothorax and on the first and seventh abdominal segments. The cornicles are fairly long, slender, and taper slightly toward the apex. They are from one and one-half to two times as long as the hind tarsi, and subequal to or very slightly longer than the cauda. The cauda is fairly long, ensiform, slightly constricted before the tip. The wings are normal, with the second branch of the third discoidal nearer the apex of the wing than the base of the first branch. Measurements : Body length, 1.19 to 1.33 mm. ; width of thorax, 0.544 to 0.561 mm.; antennae total, 0.85 to 0.918 mm.; Ill, 0.17 to 0.1785 mm. ; IV, 0.136 to 0.153 mm. ; V, 0.1275 to 0.1445 mm. ; VI, base 0.0935 to 0.102 mm. ; VI, spur 0.238 to 0.255 mm. ; cornicles, 0.1785 to 0.187 mm. ; cauda, 0.17 mm. ; hind tarsus, 0.102 mm. ; wing length, 1.97 to 2.04 mm.; width, 0.748 to 0.782 mm.; expansion, 4.55 mm.; from base of first branch of third discoidal to wing tip, 0.578 to 0.68 mm. ; from base of second branch to wing top, 0.17 to 0.255 mm. 149. Aphis tetrapteralis Cockerell Cockerell, 'South. Cal. Acad. Sci., Bull. 1, p. 4, 1902 (orig. desc.). Record. — Atriplex canescens tetraptera; La Jolla (Cockerell). This species has been observed but once, when described by Cockerell. He writes: "It differs from Aphis atriplices Linn, by its smaller size, mode of life, and shorter cornicles. It seems to be related to Aphis vnonardae Oestlund." In 1916 the author spent considerable time hunting for this species in the vicinity of La Jolla, but in vain. is Patch, Edith M., Maine Aphids of the Rose Family. Maine Agr. Exp. Sta., Bull. 233, p. 270, 1914, Aphis spiraecola n.n.; Gillette, C. P., Plant louse notes, Family Aphididae. Jour. Econ. Ent., vol. 3, p. 404, 1910. Aphis spiraeella Schout. 126 MISCELLANEOUS STUDIES 150. Aphis viburnicolens n.sp. Becords. — Viburnum tinua; Riverside, February to May, 1917; Redlands, Feb- ruary, 1917; Orange, February, 1917: Laurus rotoundifolia, Riverside, March, 1917. In the early spring there is a small green and black aphid that attacks in great numbers the racemes of laurustinus and laurel in Southern California. In fact, it is so abundant at times as to seriously injure the plants by preventing them from flowering. The leaves and buds are very sticky and covered with the sooty mold fungus. During April, 1917, all the aphids left the laurel and laurustinus, but the alternate host has as yet not been observed. Specimens were sent to Gillette and Patch for determination, but neither could identify them. Dr. Patch wrote as follows: This insect is not spiraecola, a slide of which I am sending you. spiraecola sp. Cornicles longer than III Cornicles shorter than III VI spur longer than III VI spur subequal to III VI spur longer than IV and V VI spur subequal to IV and V IV subequal to V IV longer than V I do not know this species. I do not have spiraeella Schout. for comparison. Gillette stated concerning this species: "This is a species of Aphis close to, but almost certainly distinct from, spiraeella Schout., and so far as we know, may be new. ' ' From this it would appear that the species from laurustinus and laurel is a new species, and it is described herewith as such.19 Cotype specimens are in the author's private collection, in the collection of the University of California in Berkeley, and of the Citrus Experi- ment Station in Riverside. Alate viviparous female. — Prevailing color green. Head and thorax dusky brown to black. Antennae dusky to black. Beak light brown with tip black. Tibiae, femora of fore legs, and basal one-half of femora of middle and hind legs brown ; tarsi, tips of tibiae, tips of fore femora, and apical one-half of middle and hind femora black. Abdomen pale to apple green, sometimes with a few dusky marginal spots. Cornicles and cauda black. is The species reported by Davidson (Jour. Econ. Ent., vol. 3, p. 377, 1910) as Aphis mali Fabr. from Lauras laurustinus (Viburnum tinus?) and by Essig (Injurious and Beneficial Insects of California, Mon. Bull. Cal. Comm. Hort., Supp. vol. 4, p. xlvi, 1915) as Aphis pomi De Geer from laurustinus, are probably this species. A SYNOPSIS OF THE APHIDIDAE 127 Head normal, with frontal and antennal tubercles absent. An- tennae short, reaching only to the second abdominal segment. Ill and VI spur subequal ; IV and V subequal and about three-fourths as long as III or VI spur. The usual primary sensoria are present on V and VI, and the accessory sensoria on VI. Secondary sensoria are found on III and IV, from five to nine on the former and from one to four on the latter. Cornicles short, subcylindrical, and tapering from base toward apex. Cauda fairly long, ensiform, with a slight constriction in the middle, the cauda is slightly longer than the hind tarsi, and the cornicles a little longer than the cauda. Lateral tuber- cles are present on the prothorax, and on the first, fourth, and seventh abdominal segments. The cornicles are subequal to IV or V. The hind tarsi are somewhat longer than VI base. The wings are fairly large, with regular venation, the second joint of the third discoidal arising about half way between the tip of the wing and the base of the first joint. Measurements: Body length, 1.214 to 1.479 mm. (av. 1.372 mm.) ; width of thorax, 0.476 to 0.578 mm. (av. 0.5338 mm.) ; antennae total, 0.733 to 0.918 mm. (av. 0.8925 mm.) ; HI, 0.187 to 0.230 mm. (av. 0.2067 mm.) ; IV, 0.136 to 0.161 mm. (av. 0.1473 mm.) ; V, 0.119 to 0.153 mm. (av. 0.1416 mm.) ; VI, base 0.085 to 0.102 mm. (av. 0.0877 mm.) ; VI, spur 0.204 to 0.230 mm. (av. 0.216 mm.) ; cornicles, 0.127 to 0.153 mm. (av. 0.1422 mm.) ; cauda, 0.110 to 0.136 mm. (av. 0.1252 mm.) ; hind tarsi, 0.102 to 0.119 mm. (av. 0.1023 mm.) ; wing length, 1.921 to 2.397 mm. (av. 2.167 mm.) ; width, 0.799 to 0.935 mm. (av. 0.8704 mm.) ; expansion, 4.42 to 5.304 mm. (av. 4.875 mm.). Apterous viviparous female. — General color green with the follow- ing dusky to black: head, antennae, apex of beak, cornicles, cauda, distal margin anal plate, tarsi, and tips of tibiae. Legs, except tarsi and tips of tibiae, dusky brownish green. Antennae reach to the base of the second abdominal segment. The various segments are propor- tionally the same as in the alates. The beak reaches to the distal margin of the first coxae or almost to the apical margin of the third coxae. Lateral body tubercles are present on the prothorax and first, second, and seventh abdominal segments. Sometimes they are also present on the third, fourth, or fifth abdominal segments as well. The cornicles and cauda are subequal, each slightly longer than the hind tarsi, and of the same form as in the alates. Measurements: Body length, 1.326 to 1.462 mm. (av. 1.3685 mm.) ; width of thorax, 0.595 to 0.68 mm. (av. 0.6975 mm.) ; antennae total 128 MISCELLANEOUS STUDIES 0.731 to 0.782 mm. (av. 0.748 mm.) ; III, 0.153 to 0.187 mm. (av. 0.170 mm.) ; IV, 0.119 to 0.136 mm. (av. 0.1224 mm.) ; V, 0.119 mm.; VI, base 0.085 mm.; VI, spur 0.136 to 0.1995 mm. (av. 0.1632 mm.) ; cornicles, 0.153 to 0.1995 mm. (av. 0.170 mm.) ; cauda, 0.136 to 0.170 mm. (av. 0.162 mm.) ; hind tarsi, 0.102 to 0.119 mm. (av. 0.114 mm.). 151. Aphis yuccae Co wen Figures 303 to 305 Cowen, Colo. Agr. Exp. Sta., Bull. 31, p. 122, 1895 (orig. dese.). Williams, Univ. Neb. Studies, vol. 10, p. 145, 1910. Aphis yuccicola n.sp. (desc.). Records. — Yucca moJuivensis; Moorpark, Ventura County, April, 1916 (F. M. Trimble) ; San Diego, May, 1916. In April, 1916, Horticultural Inspector F. M. Trimble of Ventura County sent the author a few specimens of the alate and apterous viviparous females of this species, taken on Spanish dagger in Moor- park. In the latter part of the next month the author found a few apterae on the leaves of Spanish dagger in Golden Hill Park, San Diego. There were only a few individuals present at that time, but there was evidence of an earlier heavy infestation. Following are a few notes to supplement Williams ' excellent description of this species. Ill is the longest segment of the antennae, followed by VI spur, which is about three-fourths as long. IV is next, being a little over one-half as long as III and about five-sixths as long as VI spur. V is slightly shorter than IV and is followed closely by VI base, which is about one-half the length of the spur. The usual primary sensoria are present on V and VI and the accessory sensoria on VI (fig. 303). The apterae have no secondary sensoria, while the alates along the whole length of III (fig. 304) have about twenty-five irregularly placed sensoria of irregular size. VI is without sensoria. Lateral tubercles are present on the prothorax and on the first and seventh abdominal segments. The cornicles (fig. 305) are long and slightly tapering, being but slightly shorter than the spur of the sixth antennal segment and about twice as long as the hind tarsi. The cauda (fig. 305) is ensiform or sickle-shaped and about three-fourths as long as the cornicles. In length it is about equal to the fifth antennal seg- ment and one-half again as long as the hind tarsi. A SYNOPSIS OF THE APHIDIDAE 129 Alate viviparous females. — Measurments : Body length, 1.78 to 1.9 mm. (av. 1.86 mm.) ; width, (thorax), 0.95 mm.; antennae total, 1.38 to 1.51 mm. (av. 1.449 mm.) ; III, 0.34 to 0.425 mm. (av. 0.391 mm.) ; IV, 0.238 to 0.273 mm. (av. 0.256 mm.) ; V, 0.212 to 0.229 mm. (av. 0.219 mm.) ; VI, 0.136 to 0.17 mm. (av. 0.155 mm.) ; spur, 0.255 to 0.306 mm. (av. 0.289 mm.) ; cornicles, 0.255 to 0.2975 mm. (av. 0.275 mm.) ; cauda, 0.2125 to 0.238 mm. (av. 0.225 mm.) ; hind tarsi, 0.153 mm.; wing length, 3.06 to 3.4 mm. (av. 3.19 mm.) ; wing width, 1.27 to 1.46 mm. (av. 1.338 mm.) ; wing expansion, 7.48 mm. 30. Genus Toxoptera Koch. Koch, Die Pflanzenlause, p. 253, 1857. Type Aphis aurantii Fonsc. 152. Toxoptera aurantii (Fonsc.) Figures 114, 163, 276 Boyer de Fonscolombe, Ann. Ent. Soc. France, vol. 10, 1841. Aphis (orig. desc.). Essig, Pom. Jour. Ent., vol. 3, p. 601, 1911. T. aurantiae Koch (desc.). Davis, U. S. Dept. Agr., Bur. Ent., Tech. Ser., Bull. 25, pt. 1, p. 8, 1912. Records. — Citrus spp. ; throughout citrus sections of southern and central Cali- fornia (Essig, author) ; San Jose (Davidson). This is the common black louse of the citrus trees, and is found at almost any time of the year on the younger and more tender leaves of various species of Citrus. It is more or less heavily preyed upon by the braconid fly, Lysiphlcbus testaceipcs Cresson. In fact, the author has noticed several infestations in which fully ninety-five per cent of the individuals were parasitized. Besides these the syrphid flies cause great havoc among colonies. Of these the author has reared Allograpta obliqua Say from a colony taken in the vicinity of El Cajon, San Diego County. Never does this species become abundant enough to seriously damage trees, due undoubtedly to the effective work of its predacious and parasitic enemies. Only in the spring are they found to any great extent, although occasionally throughout the year small infestation can be noticed. 130 MISCELLANEOUS STUDIES 31. Genus Hyalopterus Koch Koch, Die Pflanzenlause, p. 17, 1854. Type Aphis arundinis Fabricius ( A. pruni Fabr.). 153. Hyalopterus arundinis (Fabr.) Figures 181, 185, 186 Fabricius, Ent. Syst., vol. 4, p. 212, 1749. Aphis (orig. desc.). Clarke, Can. Ent., vol. 35, p. 247, 1903 (list). Davidson, Jour. Econ. Ent., vol. 2, p. 303, 1909 (list). Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1910 (list). Essig, Mon. Bull. Cal. Comm. Hort., vol. 2, p. 569, 1913 (list). Essig, Mon. Bull. Cal. Comm. Hort., vol. 3, p. 624, 1913. A. prunifoliae Fitch (list). Weldon, Mon. Bull. Cal. Comm. Hort., vol. 2, p. 630, 1913 (list). Weldon, Mon. Bull. Cal. Comm. Hort., vol. 3, p. 378, 1914 (list). Patch, Maine Agr. Exp. Sta., Bull. 233, 266, 1914 (dese.). Davidson, Mon. Bull. Cal. Comm. Hort., vol. 6, p. 64, 1917 (note). Records. — Prunus spp., Phalaria, arundinacea, Phragmites communis, Typha latifolia; central California. During the spring and early summer of the year this ' ' mealy-plum louse" is often very abundant on various species of Prunus in the central part of the state, especially in the San Francisco Bay region and the Sacramento Valley. As summer continues all the aphids desert the plum for other host plants, where they remain until fall. The summer hosts in California so far known are reed grass, canary grass, and tule, or cat-tail rush. In the Santa Clara Valley there is a feeling among the prune growers that this aphid is the cause of the splitting of the prunes, which is often quite extensive. However, this remains to be proven. 32. Genus Liosomaphis Walker Walker, The Zoologist, p. 1119, 1868. Type Aphis berberidis Kalt. 154. Liosomaphis berberidis (Ealt.) Figures 184, 251, 252 Kaltenbach, Monog. d. Pflanzenlause, p. 85, 1843. Aphis (orig. desc.). Davis, Ann. Ent. Soc. Am., vol. 1, p. 254, 1908. Bhopalosiphum (desc.). Davidson, Jour. Econ. Ent., vol. 3, p. 378, 1910. Bhopalosiphum (list). Eecords. — Berberis vulgaris; Stanford University (Davidson); February to May, 1915; Berkeley, June to August, 1915. This species is found throughout the year on the lower sides of the leaves of barberry in the San Francisco Bay region. The apterae are often very abundant, but the alates are always quite scarce. This A SYNOPSIS OF THE APHIDIDAE 131 species is similar to species of Rhopalosiphum, particularly in the shape of the cornicles and cauda, but owing to the absence of antennal tubercles it falls into the tribe Aphidini instead of Macrosiphini. Hence Walker's genus Liosomaphis is maintained for this species. 33. Genus Siphocoryne Passerini Passerini, Gli Afidi, 1860. Type Aphis pastinacae Linn, (xylostei Schrank). There has been much diversity of opinion concerning this genus, some aphidologists considering it as Siphocoryne Passerini, some as Hyadaphis Kirkaldy, and some as a synonym of Rhopalosiphum Koch. This last is incorrect as this is most certainly not a Macrosiphini for the antennal tubercles are lacking. In 1904 Kirkaldy proposed the name Hyadaphis to replace Siphocoryne, but in the author's opinion this is uncalled for, so he maintains the original name, Siphocoryne Passerini. There have been reported from various parts of California eight species of Siphocoryne as follows: capreae (Fabr.), conii (Dvdn.), foeniculi (Schrank), nymphaeae (Linn.), pastinacae (Linn.), salicis (Monell), umbellulariae (Dvdn.), and xylostei (Schrank). There are, however, really but three species; capreae (Fabr.), nymphaeae (Linn.) and pastinacae (Linn.). According to Gillette,20 S. salicis Monell is a synonym of S. capreae (Fabr.), and xylostei (Schr.) of pastinacae (Linn.). Davidson21 states that S. conii (Dvdn.) is a synonym of xylostei ( Schr. ) , and therefore it is the same as pastinacae (Linn.). Morrison writes that the specimens Davidson called S. foeni- culi (Schr.) are capreae (Fabr.), and those he described as Hyadaphis umbellulariae n.sp. are S. pastinacae (Linn.). These two species, pastinacae (Linn.) and capreae (Fabr.), have been greatly confused but Gillette22 has worked out their synonymy quite satisfactorily. The following key for distinguishing them is from his paper. Joints 4, 5, 6, and antennal spur subequal, the spur usually distinctly the longest, cornicles fully three-fourths as long as third joint of the antenna, a small tubercle on the alate form and a large one on the apterous individuals always present capreae 20 Gillette, C. P., Two Rhopalosiphum species and Aphis pulverulens n.sp., Jour. Econ. Ent., vol. 4, pp. 320-325, 1911. 21 Davidson, W. M., Plant louse notes from California, Jour. Econ. Ent., vol. 7, p. 133, 1914. 22 Gillette, C. P., Two Rhopalosiphum species and Aphis pulverulens n.sp., Jour. Econ. Ent., vol. 4, pp. 320-325, 1911. 132 MISCELLANEOUS STUDIES Joint 623 of the antenna distinctly shorter than 5, the fourth still shorter and its spur nearly as long as joints 4, 5, and 6 combined, cornicles seldom much exceeding one-half the third joint of the antenna in length, and a supra-caudal tubercle or spine entirely absent pastinacae Aphis nymphaeae Linn, has usually been considered by American aphidologists as a species of Rhopalosiphum, but the presence of lat- eral body tubercles, the short, robust body, and the absence of antennal tubercles place it in the Aphidini rather than the Macrosiphini. Therefore, it must be considered as belonging to this genus. Baker24 has recently recognized it as belonging here. KEY TO CALIFORNIAN SPECIES 1. A small spine or tubercle present at the distal end of the body just above the cauda (figs. 255, 256) capreae (Fabr.) — No supra-caudal tubercle or spine 2 2. General color pale green. VI spur as long as IV, V and VI base combined. Cornicles at most but slightly more than one-half the length of III. pastinacae (Linn.) — General color dark brown, wine, or black. VI spur not as long as IV, V and VI base combined, although longer than any two together. Cornicles and III subequal nymphaeae (Linn.) 155. Siphocoryne capreae Fabr. Fabricius, Ent. Syst., p. 211, 1794. Aphis (orig. desc.). Clarke, Can. Ent., vol. 35, p. 252, 1903. S. foeniculi (Pass.) (list). Davidson, Jour. Econ., vol. 2, p. 303, 1909. S. solids Monell (list). Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1910. S. foeniculi (Pass.), (list). Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1910. S. salicis Monell (list). Essig, Pom. Jour. Ent., vol. 3, p. 534, 1911. Hyadaphis pastin-acae (Linn.) (desc.). Becords. — Foeniculum vulgare; Berkeley and Newcastle (Clarke), Stanford University (Davidson): Carum spp. ; Cicuta virosa; Santa Paula, Berkeley (Essig) : Salix laevigata; Santa Paula (Essig), Brea Canyon, Los Angeles County, April, 1917; Riverside, May, 1917:- Salix nigra; Lakeside, San Diego County, April, 1916: Salix sp., Stanford University (Davidson). This species is found more or less abundantly in the spring on the tender shoots and leaves of willows, migrating in early . summer to various species of Umbelliferae. It is more common than 8. pastinacae (Linn.), which species is also found on Umbelliferae in the summer, but which passes the fall, winter, and spring on honeysuckle. 23 In all the author 's specimens, VI is shorter than V, which in turn is shorter than IV, while VI spur is nearly as long as the three together. 2* Baker, A. C. and Quaintanee, A. L. Aphids injurious to orchard fruits, currant, gooseberry and grape, U. S. Dept. Agr., Farmers' Bulletin 804, p. 21, 1917. A SYNOPSIS OF THE APHIDIDAE 133 156. Siphocoryne nymphaeae Linn. Figure 172 Linnaeus, Syst. Nat., vol. 2, p. 734, 1735. Aphis (orig. dese.). Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1910. Rhopalosiplium (list). Essig, Pom. Jour. Ent., vol. 4, p. 793, 1912. Ehopalosiphum (desc.). Davidson, Mon. Bull. Cal. Comm. Hort., vol. 6, p. 65, 1917. Ehopalosiphum (note). Records. — Polygonum sp., Alisma sp., Potamogeton sp. ; San Francisco Bay region (Davidson) : Typha latifolia; Santa Paula (Essig), San Francisco Bay region (Davidson): Nymphaea sp.; San Francisco Bay region (Davidson), Fresno, June, 1915: Prunus domestica; Berkeley, 1916 (Essig). This aphid occurs throughout the summer months on various semi- aquatic plants, lily, tule, and so forth. In the fall it migrates to plum, where eggs are laid. The first two or three generations in the spring occur on plum, but about June there is a migration to its sum- mer host plants. So far it has been found in southern California only in Ventura County. The species listed as Aphis prunorum Dobr. (see no. 140) may be this species. Essig believes it is, but the author is not certain so does not list it as a synonym. 157. Siphocoryne pastinacae Linn. Figures 266 to 270 Linnaeus, Syst. Nat., p. 451, 1735. Aphis (orig. desc.). Davidson, Jour. Eeon. Ent., vol. 2, p. 304, 1909. S. xylostei (Schr.) (list). Davidson, Jour. Econ. Ent., vol. 2, p. 304, 1909. S. conii n.sp. (desc.). Davidson, Jour. Econ. Ent., vol. 3, p. 377, 1910. S. xylostei (Schr.) and S. conii Dvdn. (list). Davidson, Jour. Econ. Ent., vol. 4, p. 599, 1911. Hyadaphis umbellulariae n.sp. (desc.). Davidson, Pom. Jour. Ent., vol. 3, p. 399, 1911. S. conii Dvdn. (list). Davidson, Jour. Econ. Ent., vol. 7, p. 133, 1914. S. xylostei (Schr.) (list). Records. — Lonicera sp. ; Stanford University (Davidson), Claremont (Essig), Berkeley, April, 1915: Umbellularia calif ornica; San Jose (Davidson): Conium maculatum; Stanford University, Penryn, Placer County, and San Jose (David- son). This aphid occurs on honeysuckle during the winter and spring, and on various semiaquatic plants in the summer. It has been taken in southern California, in the San Francisco Bay region, and in the Sacramento Valley. 134 MISCELLANEOUS STUDIES 34. Genus Myzaphis Van der Goot Van der Goot, Ziir Systematik der Aphiden, Tijdscrift voor Entomologie, vol. 56, p. 96, 1913. Type Aphis rosarum Walker. The author believes that this genus of Van der Goot's should be accepted for the two following species: Aphis abietina Walker and Aphis rosarum Walker. A. rosarum has usually been considered as belonging to the genus Myzus, but the absence of antennal tubercles excludes it from that genus (see figs. 306-308, 313). The cornicles and cauda are not typical of Aphis, and these together with the dis- tinctive frontal tubercle on the head and the absence of lateral body tubercles distinguish it from Aphis. Consequently this genus should be recognized. Following is a key for separating the two known species, both of which occur in California : Cornicles slightly clavate (figs. 312, 315), shorter than III. Ill tuberculate, IV without sensoria (fig. 309). Found on Rosa spp rosarum (Walker) Cornicles cylindrical (fig. 197), equal to or longer than III. Ill with 9 to 12 rather large secondary sensoria, IV with 1 to 4 (fig. 196). On conifers. abietina (Walker) 158. Myzaphis abietina (Walker) Figures 196, 197 Walker, Ann. Mag. Nat. Hist., vol. 3, p. 301, 1848. Aphis (orig. desc.). Wilson, Proc. Ent. Soc. Brit. Columbia, June, 1915 (desc.). Record. — Picea excelsa; San Francisco, March, 1915 (Compere). The only report of this species in America is that of Wilson, who found it on spruce (Picea sp.) at Vancouver, British Columbia. On March 26, 1915, Harold Compere of San Francisco took a number of specimens of this species on the twigs of Norway spruce (Picea excelsa) in Golden Gate Park, San Francisco. The specimens are in Essig 's and the author's collections. 159. Myzaphis rosarum (Walker) Figures 308 to 317 Walker, Ann. Mag. Nat. Hist., voL 3, 1848. Aphis (orig. desc.). Davidson, Jour. Econ. Ent., vol. 3, p. 379, 1910. Myzus (list) Eecords. — Rosa spp.; Stanford University (Davidson); Santa Paula (Essig), San Diego, March to July, 1916. This species has been reported in the San Francisco Bay region by Davidson and in Santa Paula by Essig. In the Bay region it is rather scarce and is second to Macrosiphum rosae (Linn.) in abun- dance on roses. The author has taken it at Stanford University in 1915, and in San Diego several times in 1916. In San Diego in 1916 it was by far the most abundant rose-infesting aphid. The author 135 has observed it in such numbers on roses as to cover the undersides of practically all the leaves and the calyx cups of the flowers. In some cases the buds were stunted and the flowers unshapely from its effect. In the rose garden of the Panama-California International Exposition these aphids were of considerable importance, necessitating continual care to keep them under control. Since there is no adequate description of this species in the Ameri- can aphid literature the author describes it herewith. The following description was drawn from ten specimens of alate and eight of apterae, collected in Santa Paula, Stanford University, and San Diego. Alate viviparous female. — Color notes (taken from notes made at the time of collection of specimens at Stanford in March, 1915) : Head, antennae, and thoracic plates black. Abdomen pale apple green with smoky blotch on dorsum. Legs : apical two-thirds of femora smoky, basal one-third pale, tibiae pale except dusky tip, tarsi dusky. Cornicles green (dusky), cauda pale apple green. Head is twice as wide as long with a fairly distinct tubercle on the front (fig. 308). Antennal tubercles are lacking or very indistinct. Antennae reach almost to the base of the third abdominal segment (figs. 309, 310). Ill is the longest segment, followed by IV, spur, V, and VI. The spur and IV are practically equal. Of sixteen antennae examined, in three, the spur and IV were equal, in ten, IV was slightly longer than the spur, while in three, the spur was slightly longer than IV. V is slightly shorter than the spur, and VI slightly shorter than V. However, IV, spur, V, and VI are all almost equal. On V and VI are the usual primary sensoria, and VI the accessory sensoria (fig. 300). Ill is tuberculate, being furnished with a large number of irregularly placed secondary sensoria (fig. 309). IV is without any sensoria. The beak reaches almost to the second coxae. The prothorax is without lateral tubercles. The wings are normal, being about twice the length of the body. The second branch of the cubitus arises nearer the apex of the wing than the base of the first branch (fig. 311). In but one of seventeen specimens examined was the origin of the second branch of the cubitus nearer the base of the first branch than the tip of the wing. In this specimen the measure- ments were : 0.561 mm. from tip of wing to base of first branch and 0.289 mm. from tip of wing to base of second branch. The abdomen is long and narrow and is without lateral body tubercles. The cornicles (fig. 312) are long, being but slightly shorter than the third antennal segment, and over twice as long as the hind tarsi. They are slightly clavate on the inner side. The cauda (fig. 136 MISCELLANEOUS STUDIES 312) is long and pointed (ensiform), being slightly more than one-half as long as the cornicles and about one-half as long again as the hind tarsi. Measurements : Body length, 1.19 to 1.41 mm. (av. 1.28 mm.); width of thorax, 0.459 to 0.527 mm. (av. 0.487 mm.) ; antennae total, 0.85 to 1.156 mm. (av. 1.027 mm.) ; III, 0.255 to 0.34 mm. (av. 0.317 mm.) ; IV, 0.1275 to 0.2295 mm. (av. 0.1768 mm.) ; V, 0.119 to 0.17 mm. (av. 0.1365 mm.) ; VI, 0.085 to 0.119 mm. (av. 0.1095 mm.) ; spur, 0.119 to 0.204 mm. (av. 0.1695 mm.) ; cornicles, 0.238 to 0.306 mm. (av. 0.2574 mm.) ; cauda, 0.136 to 0.187 mm. (av. 0.1588 mm.) ; hind tarsi, 0.119 to 0.136 mm. (av. 0.1205 mm.) ; wing length, 2.482 to 2.72 mm. (av. 2.5483 mm.) ; wing width, 0.884 to 1.02 mm. (av. 0.9396 mm.) ; wing expansion 5.423 to 5.967 mm. (av. 5.5836 mm.). From tip of wing to base of first branch of cubitus 0.561 to 1.037 mm. (av. 0.8041 mm.) ; from tip of wing to base of second branch of cubitus, 0.17 to 0.34 mm. (av. 0.2907 mm.). Apterous viviparous female. — Head about as long as broad with a large prominent tubercle on the front, this tubercle being considerably larger than in the alate form ; in some individuals it is fully as large as the first antennal segment (fig. 313). Antennal tubercles small but distinct, similar to those of the alate. Antennae (fig. 314) short, reaching only to the third coxae. Ill is the longest segment, followed by the spur, IV, VI, and V. These are all subequal, the formula of the averages being spur, IV, VI, and V. The formulae for seven antennae are S, VI (V, IV) ; S, (VI, V, IV) ; S, V, IV, VI; S, IV (V, VI) ; S, (IV, V), VI; IV (V, VI, S) ; (S, VI, IV), V. The usual primary sensoria are present, but there are no secondary sensoria. The beak is short, reaching only to the second coxae. The prothorax is without tubercles. The thorax is normal, as are the legs. The abdomen is long and narrow, without lateral tubercles, and without long capitate hairs as found in some species of Myzus. The cornicles (fig. 315) are long, cylindrical, and slightly tapering toward the apex, or slightly clavate at apex. They are over twice as long as the third antennal segment and over three times as long as the hind tarsi (fig. 317), and half as long again as the cauda. The cauda (fig. 316) is long and ensiform, being slightly more than twice the length of the hind tarsi, and about two-thirds the length of the cornicles. Measurements: Body length, 1.275 to 1.615 mm. (av. 1.428 mm.) ; width of thorax, 0.493 to 0.748 mm. (av. 0.6375 mm.) ; antennae total, 0.544 to 0.731 mm. (av. 0.6239 mm.) ; III, 0.153 to 0.238 mm. (av. A SYNOPSIS OF THE APHIDIDAE 137 0.178 mm.) ; IV, 0.068 to 0.119 mm. (av. 0.0855 mm.) ; V, 0.068 to 0.102 mm. (av. 0.0833 mm.) ; VI, 0.068 to 0.119 mm. (av. 0.085 mm.) ; spur, 0.085 to 0.136 mm. (av. 0.117 mm.) ; cornicles, 0.306 to 0.442 mm. (av. 0.3655 mm.) ; cauda, 0.204 to 0.272 mm. (av. 0.2338 mm.) ; hind tarsi, 0.102 mm. (Note : no color notes were taken of the apterae at the time of collection and as all the specimens were killed in alcohol, dehydrated in xylene and mounted in Canadian balsam, it is impossible to give any color notes.) 35. Genus Coloradoa Wilson Wilson, Ann. Ent. Soc. Am., vol. 3, p. 323, 1910. Type Aphis rufomaculata Wilson. This genus was described by Wilson in 1910 to contain the species Aphis rufomaculata Wilson. After examining specimens of this species recently, the author is of the opinion that Coloradoa and Myzaphis are synonymous, for there does not seem to be enough differ- ence between this species and the two species of Myzaphis to warrant a separation of genera. However, the author does not feel certain concerning the point, so lists both these genera. Should they later prove to be synonymous, Myzaphis would have to be dropped and replaced by Coloradoa. There is but one species belonging to this genus. 160. Coloradoa rufomaculata Wilson Wilson, Ent. News, vol. 14, p. 261, 1908. Aphis (orig. desc.). Eecord. — Chrysanthemum, cultivated; Sacramento, April, 1917 (Davidson). The author has recently received specimens of this species from Davidson taken on chrysanthemum in Sacramento. 36. Genus Cerosipha Del Guercio Del Guercio, Nouve relazione agraria di Firenze, vol. 2, p. 116, 1909. Type C. passeriniana n.sp. 161. Cerosipha cupressi Swain Swain, Trans. Am. Ent. Soc., vol. 44, p. 19, 1918 (orig. desc.). Records. — Cupressus guadelupensis ; San Diego, 1916; Riverside, 1917; C. macrocarpa, San Diego, 1916. This species, recently described by the author, has been taken by him several times in San Diego and Riverside on blue cypress and Monterey cypress. It is an extremely interesting little aphid, differ- ing considerably from any other species known to the author, both in habits and appearance. Its five-jointed antennae, long cauda, atrophied cornicles, and convexity of abdomen are quite distinctive. 138 MISCELLANEOUS STUDIES Subfamily Pemphiginae Mordwilko25 Mordwilko, Ann. Mus. Zool. Imp. Acad. Sci. St. Petersburg, vol. 13, pp. 362-364, 1908. A summary of Mordwilko 's description of this subfamily has already been given. The latest and probably the most complete sys- tematic work on this subfamily that has been done is that of Dr. Albert Tullgren of Stockholm, Sweden, in his paper, ' ' Aphidologische Studien I" in 1909. Tullgren divides this subfamily into six tribes, viz: Vacunina, Hormaphidina, Mindarina, Pemphigina, Schizoneu- rina, and Anoeciina. In the tribe Vacunina he places Vacuna Heyden and Glyphina Koch ; in Hormaphidina is the one genus Hamamelistes Shimmer; in Mindarina is the one genus Mindarus Koch; in Pem- phigina he places Asiphum Koch, Pachypappa Koch, ProciphUus Koch, Thecdbius Koch, and Pemphigus Hartig; in Schizoneurina he places the two genera, Schizoneura Hartig, and Tetraneura Hartig; and finally in the Anoeciina is found the one genus Anoecia Koch. It can be seen that he uses several of Koch 's genera which have not here- tofore been generally used, namely: Prociphilus Koch, Thecabius Koch, Asiphum Koch, and so forth. Lately there has been a tendency among American aphidologists to accept these genera, and thus to divide up the larger genus Pemphigus into these smaller ones. Mord- wilko in his keys divides this subfamily into four groups, namely: Hormaphidina, Pemphigina, Schizoneurina, and Vacunina. In Hor- maphidina he includes besides the genus Hamamilestes Shimmer, the genera Hormaphis Osten-Sacken and Cerataphis Lichtenstein. In Pemphigina he includes Pentaphis Heyden, Tetraneura Hartig, Pemphigus Hartig, Aploneura Passerini, Rhizoctonus Horvath, and Paracletus Heyden. In Schizoneurina he places Lowia Lichtenstein, Colopha Monell, Pachypappa Koch, Schizoneura Hartig, Anoecia, Koch, and Mindarus Koch. In Vacunina he includes but the one genus Vacuna Heyden, which he does not separate from Glyphina Koch. There is considerable difference in the classifications of these two authors, but as far as we are concerned here in California our genera are placed about the same by both. Following is a translation of Mordwilko 's key to the groups : 2", The author has under way a more exhaustive study of this subfamily, par- ticularly of the species of Pemphigus and Procipliilus. As this research is still in progress, however, it was thought best to omit any report of it, the author here confining himself merely to the records of the presence of the various species in California. It was hoped to have this study completed at the present time, but the unprecedented conditions of this season have made it necessary to delay further study for the time being. A SYNOPSIS OF THE APHIDIDAE 139 1. Winged forms with a cucurbit-shaped cauda. Nymphs that failed to molt with three-jointed antennae. Winged forms with three to five-jointed antennae, which are coarsely ringed from the third on. Wingless partheno- genetic females presenting the appearance of the larvae of other families, as of some kinds of Coccidae, or of species of Aleyrodes. Sexual forms with beaks Group Hormaphidina — Winged forms without distinct cauda. Nymphs that failed to molt with four to five- jointed antennae. Antennae of winged females five-to six- jointed. Sensoria may be found on the third and following joints, often in the form of arches or half rings, but never as complete rings 2 2. Cubitus [third discoidal vein] of the fore wings simple. Cornicles, which are pore or pointlike, present only in some species, and then not in all forms. Group Pemphigina — Cubitus [third discoidal vein] of fore wings once-branched. Cornicles mostly point or pore-like 3 3. Antennae of winged forms six-jointed. Wings held roof-like when at rest. Group Schizoneurina — Antennae of winged forms five-jointed. Wings held flat when at rest. Group Vacunina Group Hormaphidina Mordw. Mordwilko, Ann. Mus. Zool. Imp. Acad. Sci. St. Petersburg, vol. 13, pp. 364-365, 1908. The antennae of the winged forms are 5- to 3-jointed (?). With the exception of the first two joints they are closely and entirely ringed. Even in the genus Hormaphis O.-S., where the antennae are 3-jointed, they may probably be con- sidered morphologically as of five joints. The wings are held flat at rest. There are four transverse veins on the fore wings, the third of which [third discoidal] is simple. The first two [first and second discoidals] originate at the same point on the subcosta. The hind wings have one or two transverse veins, in the latter case both originating at the same point. The wingless parthenogenetic females on the alternate host plants (for example on birch) are mostly circular in shape, and have small wax tubes around them. Other forms are coccid-like. The sexual forms have beaks. The cornicles are absent. This is a description as given by Mordwilko in the above mentioned paper. Below is a key to the genera, as given by Mordwilko and by Van der Goot, the latter of whom includes in this group the two genera Hamamelestes Shimmer and Ceratophis Licht. 1. Antennae of winged females plainly five-jointed 2 — Antennae of winged females only three-jointed Hormaphis O.-S. 2. Antennae always five-jointed. Front of head always with two little horns. Third discoidal once-branched Cerataphis Lichtenstein — Antennae of apterous forms three- or four-jointed. Front without horns. Third discoidal simple Hamamelistes Shim. 140 MISCELLANEOUS STUDIES 37. Genus Cerataphis Liechtenstein Lichtenstein, Bull. Soci6te ent. de France, vol. 2, p. 16, 1882. Type Coccus lataniae Boisd. 162. Cerataphis lataniae Boisduval Boisduval, Ent. Hort., 1867. Coccus (orig. desc.). Davidson, Jour. Econ. Ent., vol. 5, p. 404, 1912 (list). Essig, Univ. Calif. Publ. Entom., vol. 1, p. 342, 1917 (list). Eecords. — Fern, Stanford University (Davidson) ; orchid, Oakland (Essig). This coccid-like species has been reported twice in the San Fran- cisco Bay region, by Davidson and by Essig. Morrison and the author have also taken it on the same ferns on which Davidson found it in the Stanford University nursery. Group Pemphigina Lichtenstein Below is a key to the California genera of this group, adapted from Mordwilko, Tullgren and Del Guercio. Del Guercio described a genus in 1909 for Pemphigus radicicola Essig, which he called Trifidaphis. 1. Antennae of alate females five-jointed Trifidaphis Del Guer — Antennae of alate females six-jointed 2 2. Stem mothers with five- join ted antennae. Wax-gland plates on head always present and usually large. Spring and fall migrants with wax-gland plates always on mesothorax and abdomen, and usually on head. Dorsal pores never present 3 — Stem mothers with four -jointed antennae. Head normally without wax-gland plates. Dorsal pores sometimes present. Stem mothers and spring migrants (fundatrix and fundatrigenia) at first live in the same closed galls. Pemphigus Hartig 3. Secondary sensoria furnished with hairy fringe (Wimperkranz). Wax-gland plates generally large. In stem mothers there appear four very large pro- notal wax-gland plates, placed in a transverse row. All plates have a clearly chitinized border. Stem mother and migrants live together. Prociphilus Koch — Secondary sensoria without hairy fringe (Wimperkranz). Wax-gland plates generally small. In stem mothers there are six pronotal plates, of which the four middle ones are arranged in the form of a trapezium. In the winged fall migrants (sexupara) there are also transverse abdominal gland plates, which are without clearly chitinized borders. Stem mothers and spring migrants live in separate galls Thecabius Koch A SYNOPSIS OF THE APHIDIDAE 141 38. Genus Trifidaphis Del Guercio Del Guercio, Eiv. di patal. veg., vol. 3, p. 20, 1909. Type Pemphigus radi- cicola Essig. 163. Trifidaphis radicicola Essig Essig, Pom. Jour. Ent., vol. 1, p. 8, 1909. Pemphigus (orig. desc.). Baker, Pom. Jour. Ent., vol. 1, p. 74, 1909. (Translation of Del Guer- cio's description of the genus.) Essig, Pom. Jour. Ent., vol. 2, p. 283, 1910 (list). Essig, Pom. Jour. Ent., vol. 4, p. 699, 1912 (list). Eecords. — Amaranthus retroflexus, Solanum douglasii; Claremont, Santa Paula (Essig). Essig described this species from specimens taken on the roots of Amaranthus retroflexus and Solanum douglasii in Santa Paula and Claremont. Later Del Guercio described a new genus for this species based on the venation and the antennae. It seems that the type speci- men of this species had but five-jointed antennae and so of course it could not belong to the genus Pemphigus. On an examination of eight specimens, including the type specimen and seven cotypes, the author finds that the number of joints in the antennae are variable. The type specimens had both antennae with but five joints. Six antennae had but five joints, six had six distinct joints, and four had five joints in which the division into six could be made out. This divison was in the third joint at about one-third the distance from the apex. Consequently one could say that this species was typically five- jointed, but with some specimens with the third joint divided into two, or it could be said that it was typically six-jointed, but in some speci- mens a reducton occurred through the joining of the third and fourth segments. As but a few specimens were examined the author is not willing to state which is the more common, hence leaves this as a valid genus, although he is of the opinion that this really belongs to the genus Prociphilus Koch. 39. Genus Pemphigus Hartig Hartig, Jahresb. u. d. Fortschr. d. Forstwiss. u. forstliche Naturk., vol. 1, p. 645, 1837. Type Aphis bursarius Linn. This genus is represented in California by three well known species,26 P. betae Doane, P. populi-caulis Fitch, and P. populi-trans- 26 There has been taken several times a species forming elongate leaf galls on Populus fremontii, both in the San Francisco Bay region by Davidson and in San Diego County by the author, that structurally seems to be identical with P. populi- caulis Fitch, but its gall is quite distinct, being more or less similar to that of P. betae Doane. Further study may reveal the identity of this form. 142 MISCELLANEOUS STUDIES versus Riley. All of these species, during at least a part of their life cycles, infest various species of Populus, where they form more or less distinctive galls. KEY TO FUNDATRIGENIAE27 1. Secondary sensoria present only on III. Galls formed on leaf petioles, with a transverse opening on the outside of the curve populi-transversus Eiley — Secondary sensoria on other segments as well as on III 2 2. Secondary sensoria on III to VI inclusive. Galls formed by the twisting of the petiole with an oblique opening on the inside of the curve. populi-caulis Fitch — Secondary sensoria on III and IV.2® Gall formed on the under side of the leaves, being more or less elongate and opening on the upper side. betae Doane 164. Pemphigus betae Doane Doane, Ent. News., vol. 11, p. 390, 1900 (orig. desc.). Clarke, Can. Ent., vol. 35, p. 248, 1903 (list). Davidson, Jour. Econ. Ent., vol. 2, p. 299, 1909 (list). Davidson, Jour. Ecou. Ent., vol. 3, p. 372, 1910 (list). Williams, Univ. Neb. Studies, vol. 10, p. 92, 1910. P. balsamiferae n.sp. (desc. fundatrigenia). Essig, Pom. Jour. Ent., vol. 4, p. 299, 1912 (list). Maxson, Jour. Econ. Ent., vol. 9, p. 500, 1916 (note). Becords. — Beta vulgaris; San Francisco Bay region, Monterey County, Sacra- mento Valley. (Rumex spp., Chenopodium spp., etc.?) Under the name P. betae Doane, Clarke, Davidson, and Essig have reported a species of aphid infesting the roots of sugar beets, dock, Chenopodium, and other plants throughout California. Originally this species was described from specimens taken on sugar beet in Washington, but later29 it was proven that a species forming elongated leaf galls on Populus balsamifera in the spring migrated to beets, and was identical with this species. In 1916 Maxson (cited above) states that his investigations point to the fact that in Colorado there are more than one species of Pemphigus attacking the sugar beet, one of which is this species that forms the elongate leaf gall on poplar in the spring, and which is known now as P. betae Doane. 27 At present only a key to the alate migrants or fundatrigeniae occurring in galls on poplar is given. It is hoped that later, keys to all forms may be formu- lated. At present, however, the life histories of the species are not sufficiently known. 28 The sexupara or alate migrants from beets to poplars have secondary sen- soria on III to V inclusive. These form no galls on poplar, however. 29 Parker, The life history of the sugar-beet root louse, Jour. Econ. Ent., vol. 7, pp. 136-141, 1914; Gillette, Notes on some Colorado aphids having alternate host plants, Jour. Econ. Ent., vol. 8, p. 97, 1915. A SYNOPSIS OF THE APHIDIDAE 143 These observations of Maxson's together with those made by the author lead to the conclusion that all the reported cases of infestation of beets and other hosts by P. betae Doane in California do not neces- sarily refer to this species. Never have the fuiidatrix or fundatrigenia been taken on poplar in California. This strengthens the point that the aphids on beets and other hosts may not all be P. betae Doane. Further studies and observations will have to be made before this point can be settled, however. 165. Pemphigus populicaulis Fitch Fitch, Eep. Ins. N. Y., vol. 5, p. 845, 1859 (orig. desc.). Clarke, Can. Ent., vol. 35, p. 248, 1903 (list). Davidson, Jour Econ. Ent., vol. 2, p. 299, 1909 (list). Davidson, Jour. Econ. Ent., vol. 3, p. 372, 1910 (list). Davidson, Jour. Econ. Ent., vol. 3, p. 372, 1910. P. populi-transversus Biley (list). Davidson, Pom. Jour. Ent., vol. 3, p. 398, 1911. P. populi-transversus Riley (list). Essig, Pom. Jour. Ent., vol. 4, p. 699, 1912 (list). Essig, Pom. Jour. Ent., vol. 4, p. 708, 1912 (dese.). Davidson, Jour. Econ. Ent., vol. 8, p. 420, 1915 (sexuales). Records. — Populus fremontii, P. trichocarpa; from Placer County to San Diego County (Clarke, Davidson, Essig, Morrison, and the author). The species infests cottonwoods throughout the state, forming a gall by the twisting of the leaf petiole. The sexuales are found, according to Davidson, under the bark where the eggs are also laid. The author has found the species in San Diego County, having taken the fundatrix, virgogenia, and fundatrigenia in galls in May, 1916, and the dead sexupara at the same time in old galls. These latter probably died without ever leaving the galls. 166. Pemphigus populi-transversus Riley Eiley, U. S. Geog. Geol. Surv., Bull. 5, p. 15, 1880 (orig. desc.). Essig, Univ. Calif. Publ. Entom., vol. 1, p. 343, 1917 (list). Records. — Populus fremontii, Berkeley, September, 1914 (Essig), Eiverside September to October, 1916, May to July, 1917. This species forms large galls on the leaf petioles of poplar some- what similar to the preceding species, differing in that the opening is on the opposite side of the gall, and is transverse rather than oblique. Essig 's specimens were determined by Gillette, the author's by Max- son. Davidson reported a species under this name from Stanford 144 MISCELLANEOUS STUDIES University, but later wrote the author that he was mistaken in his determination, the species being P. populicaulis Fitch instead. Just recently the author received specimens of the sexupara of this species from J. R. Parker, Bozeman, Montana. These were taken by S. H. Jones in Port Allen, Louisiana, in September, 1915, on the roots of cabbages. Jones notes that cabbage and other cruciferous plants are the alternate host of this species. This spring the author received a large number of apterae of a species of Pemphigus taken in Orange County on the roots of cabbage. A specific determination of the species was impossible but it may have been this one. 40. Genus Thecabius Koch Koch, Die Pflanzenlause, p. 294, 1857. Type Pemphigus affinis Kalt. This genus is very similar to Prociphilus, and by some authors, particularly Baker,30 is considered as synonymous. However, for present purposes the author proposes to retain it for the three species included herewith. KEY TO CALIFOBNIAN SPECIES 1. Antennae short, barely reaching to the metathorax, and not one-third as long as the body. Ill but slightly longer than VI populi-monilis Eiley — Antennae longer, reaching beyond the base of the abdomen, and about one-half as long as the body. Ill considerably longer than VI 2 2. V and VI with secondary seusoria populi-conduplifolius Cowen — VI without secondary sensoria californicus Davidson 167. Thecabius californicus (Davidson) Davidson, Jour. Econ. Ent., vol. 3, p. 372, 1910. Pemphigus ranunculi n.sp. (orig. desc.). Davidson, Jour. Econ. Ent., vol. 4, p. 414, 1911, renamed Pemphigus cali- fornicus Dvdn. Essig, Pom. Jour. Ent., vol. 4, p. 699, 1912. Pemphigus (desc. ala. and apt. female). Davidson, Jour. Econ. Ent., vol. 7, p. 127, 1914 (note). Records. — Ranunculus californicus; San Francisco Bay region (Davidson, Mor- rison, Essig, author): ? Populus sp. ; Walnut Creek, Contra Costa County, May, 1915 (Davidson) : Fraxinus oregona; Walnut Creek (Davidson). This aphid is found quite abundantly on the roots and stems of the small California buttercup in the San Francisco Bay region. According to Davidson there is a migration during April from butter- so Baker, A. C., Identity of Eriosome pyri, Jour. Agr. Ees., vol. 5, p. 1118, A SYNOPSIS OF THE APHIDIDAE 145 cup to ash. There may be a migration to poplar as well, for the .author has specimens that seem to be this species taken by Davidson •on poplar. Gillette31 places this species as a synonym of T. populi- •conduplifolius Cowen, which attacks both Ranunculus and Populus in Colorado. Davidson, however, is convinced that they are distinct. 168. Thecabius populiconduplifolius (Cowen) Cowen, Colo. Agr. Exp. Sta., Bull. 31, p. 115, 1895. Pemphigus (orig. desc.). Davidson, Jour. Econ. Ent., vol. 3, p. 374, 1910. Pemphigus (list). Essig, Pom. Jour. Ent., vol. 4, p. 699, 1912. Pemphigus (list). Gillette, Annals Ent. Soc. Am., vol. 7, p. 61, 1914 (desc. and life history). Record. — Populus trichocarpa; Stanford University (Davidson). This species was reported by Davidson on poplar at Stanford University. Since then no further records of its occurrence in the state have been made. In Colorado, Gillette finds that the common buttercup, Ranunculus sp., is an alternate host and so considers the preceding species as a synonym. This may be possible, but it is quite doubtful. 169. Thecabius populimonilis (Riley) Eiley, U. S. Geol. Surv., Bull. 5, p. 13, 1879. Pemphigus (orig. dese.). Davidson, Jour. Econ. Ent., vol. 3, p. 374, 1910. Pemphigus (list) Davidson, Pom. Jour. Ent., vol. 3, p. 398, 1911. Pemphigus (list). Essig, Pom. Jour. Ent., vol. 4, p. 699, 1912. Pemphigus (list). Gillette, Ann. Ent. Soc. Am., vol. 6, p. 485, 1913 (desc. and life history). Records. — Populus spp. ; Tulare and Placer counties (Davidson); Santa Paula (Essig), Eiverside, 1916-1917. Throughout central and southern California this species is found on various species of Populus where it forms more or less globular galls on the upper side of the leaves near the margins. In the vicinity of Riverside the young stem mothers began to appear in April (1917). When first observed in September, 1916, nearly all the galls were empty while a few contained alate migrants (sexupara probably). According to Gillette the eggs are laid on the trunks of Populus, thus the entire life cycle is passed on the one host plant. This is rather unusual for the Pemphiginae of this section. si Gillette, C. P., Some Pemphiginae attacking species of Populus in Colorado, Ann. Ent. Soc. Am., vol. 7, pp. 61-65, 1914. 146 MISCELLANEOUS STUDIES 4] . Genus Prociphilus Koch Koch, Die Pflanzenlause, p. 279, 1857. Type Aphis bumeliae Schrank. KEY TO CALIFORNIAN SPECIES 1. Stigma of forewings conspicuously darkened. V with a few annular secondary sensoria, VI with or without any. Dorsal thoracic wax plates small and oval alnlfoliae (Williams) — Stigma not conspicuously darkened. V and VI without annular secondary sensoria. Dorsal thoracic wax plates quite large and triangular. venafuscus Patch 170. Prociphilus alnifoliae (Williams) Williams, Univ. Neb. Studies, vol. 10, p. 91, 1910. Pemphigus (orig. desc.). Baker, Jour. Agr. Ees., vol. 5, p. 1118, 1916 (note). Records. — Heteromeles arbutifoliae ; Sespe, Ventura County, March, 1915 (S. H. Essig); May, 1915 (C. P. Clausen). There has been no record of this species from California heretofore, but the author has specimens taken on California holly or Christmas berry in Sespe Canyon during March and May, 1915, by S. H. Essig and C. P. Clausen. 171. Prociphilus venafuscus Patch Patch, Ent News, vol. 20, p. 319, 1909. Pemphigus (orig. desc.). Essig, Pom. Jour. Ent., vol. 3, p. 553, 1911. Pemphigus fraxini-dipetalae n.sp. (orig. desc.). Essig, Pom. Jour. Ent., vol. 4, p. 699, 1912. Pemphigus fraxini-dipetalae Essig (list). Childs, Mon. Bull. Cal. Comm. Hort., vol. 3, p. 220, 1914. Pemphigus fraxini-dipetalae Essig (list). Wilson, Trans. Am. Ent. Soc., vol. 41, p. 85, 1915. Prociphilus fraxini- dipetalae (Essig) (note). Davidson, Jour. Econ. Ent., vol. 8, p. 421, 1915. Prociphilus fraxini- dipetalae (Essig) (list). Baker, Jour. Agr. Kes., vol. 6, pp. 1118-1119, 1916 (desc. notes, synonymy). Records. — Fraxinus dipetala; Santa Paula (Essig), Contra Costa and Santa Clara counties (Davidson): F. oregona; Oregon (Wilson); Berkeley, April, 1915: Aesoulus calif or nicus ; Sacramento (Childs): Pseudotsuga taxifolia; Oregon (Wil- son). Occasionally this very large aphid is found infesting the leaves of ash in the San Francisco Bay region and in the mountains of southern California. In early summer it leaves the ash, and according to Wilson infests the roots of Douglas fir in Oregon. At one time Leroy Childs found a few specimens on buckeye in the vicinity of Sacramento, but it is probable that these were accidental there. A SYNOPSIS OF TEE APE I DID AE 147 Group Schizoneurina Lichtenstein This group as considered by Mordwilko contains the following genera : Lowia Licht., Colopha Monell, Pachypappa Koch, Schizoneura Hartig, Anoecia Koch, and Mindarus Koch. Tullgren places in his tribe Schizoneurina the two genera, Schizoneura Hartig, and Tetra- neura Hartig. Pachypappa Koch he places in his tribe Pemphigina, and he has a separate tribe for each of the genera Anoecia Koch and Mindarus Koch, calling them respectively tribe Anoeciina and tribe Mindarina. Below is a translation of Mordwilko 's key. 1. Wings laid flat on back when at rest Lbwia Licht. — Wings held roof -like when at rest 2 2. Stigma of forewings trapezoidal in shape, reaching only to the beginning of the curve around the end of the wing, never extending to the tip of the wing. Radial vein originating from the posterior exterior corner of the stigma 3 — Stigma linear, very long, reaching to the wing tip on the front side of the wing, and even following the backward curve of the exterior side of the wing to some extent. Eadial vein starting almost at the beginning to the interior edge of the stigma. Sexual forms with beaks Mindarus Koch 3. Hind wings with one transverse vein Colopha Monell — Hind wings with two transverse veins 4 4. Both transverse veins originating from the same point on the longitudinal veins Pachypappa Koch . — Transverse veins of hind wings originating separately 5 5. Bodies of apterous and alate forms with little hair, and covered at least on the dorsum of the abdomen with waxy powder. Cornicles pore-like (point-like). Sexual forms without beaks Eriosoma Leach — Bodies of apterous and alate forms very hairy and not covered with waxy powder or granules (only the stem mothers are weakly pulverulent). Cor- nicles comparatively large, tuberculate (cone-like). Sexual forms with beaks '. Anoecia Koch The genera Lowia Licht., Pachypappa Koch, and Anoecia Koch are not represented in California. Colopha Monell and Mindarus Koch are both represented by their type species. It has been proven that Eriosoma Leach has priority over Schizoneura, Hartig, so that genus is now known by that name. It is represented in California by three or four species at present. 148 MISCELLANEOUS STUDIES 42. Genus Colopha Monell Monell, Can. Ent., vol. 9, p. 102, 1877. Type Byrsocrypta ulmicola Fitch. 172. Colopha ulmicola (Pitch) Fitch, Rept. Ins. N. Y., vol. 4, p. 63, 1858. Byrsocrypta (orig. desc.). Davidson, Jour. Econ. Ent., vol. 2, p. 299, 1909 (list). Patch, Maine Agr. Exp. Sta., Bull. 181, 196, 1910 (desc.). Record. — Ulmus sp.; Stanford University (Davidson). Davidson recorded this species from elm at Stanford University in 1909. Since then it has not been found again. 43. Genus Eriosoma Leach Leach, Trans. Hort. Soc. London, vol. 3, p. 54, 1820. Type Aphis lani- gerum Hausman. Until quite recently this genus has been known as Schizoneura Hartig, but as Baker32 has pointed out, the name Eriosoma, has priority. In California there are three distinct species represented, with a possible fourth. One of these is known only on elm, one on apple (and elm), and one on pear (and elm). The following key to the fall migrants is adapted partially from a table of Baker and Davidson.33 1. Body naked except caudal segment. Distal sensoria of V and VI with fringe. languinosa (Hartig) — Body with some woolly covering. Distal sensoria without fringe 2 2. Wing veins narrow without brown margins. Ill longer than IV, V, and VI together lanigerum (Haus.) — Wing veins broad with brownish margins. Ill not so long as IV, V, and VI. americana (Biley) 173. Eriosoma americana (Riley) Eiley, TJ. S. Geol. Surv., Bull. 5, p. 4, 1879. Schizoneura (orig. desc.). Clarke, Can. Ent., vol. 35, p. 248, 1903. Schizoneura (list). Patch, Maine Agr. Exp. Sta., Bull. 220, p. 268, 1913. Schizoneura (desc. note). Becords. — Ulmus americana; Berkeley (Clarke); Walnut Creek, June, 1915 (Davidson) ; Palo Alto, May, 1915. This leaf-curling aphid of the American elm is found in. the San Francisco Bay region, and in some cases is very abundant. In May 32 Baker, A. C., The woolly apple aphis, U. S. Dept. Agr., Office Sec 'y, Report 101, pp. 11-12, 1915. sa Baker, A. C., and Davidson, W. M., Woolly pear aphis, Jour. Agr. Ees., vol. 6, p. 358, 1916. A SYNOPSIS OF THE APE I Dl DAE 149 and June, 1915, it was especially so on a row of elms on the campus of Stanford University. At that time stem mothers, nymphs, and alate spring migrants were present in the galls. By the last of June all of these had flown away, leaving the galls empty. According to Baker elm is the only host plant of this species. 174. Eriosoma lanigerum (Hausman) Hausman, Mag; Ins., vol. 1, p. 440, 1802. Aphis (orig. desc.). Davidson, Jour. Econ. Ent., vol. 2, p. 299, 1909. Schizoneura (list). Davidson, Jour. Econ. Ent., vol. 3, p. 374, 1910. Scliizoneura (list). Baker, U. S. Dept. Agr., Office Sec'y, Report 101, pp. 11-16, 1915 (desc. and biology). Record. — Pyrus mains, throughout the state. Wherever apple trees are found in the state this woolly aphis is also found ; the white masses on the trunks and leaves being very con- spicuous, the colonies on the roots more injurious but less conspicuous. In California only the -apple has been found to be attacked. The winter is passed by young nymphs on the roots. As the warmer weather of spring comes these migrate up the trunks and out on the branches and twigs. Here they feed throughout the summer. In the fall there is a downward migration, and occasionally a fall migrant is seen. Whether or not these fly to elms as in other parts of the country, is not known, but none have ever been observed on elm. 175. Eriosoma languinosa (Hartig) Hartig, Zeitschr. Ent., vol. 3, p. 359, 1841. Aphis (orig. desc.). Baker and Davidson, Jour. Agr. Res., vol. 6, pp. 351-360, 1916. E. pyricola n.sp. (desc.). Baker and Davidson, Jour. Agr. Res., vol. 10, pp. 65-74, 1917. E. pyricola B. & D. (desc. and biology). Records. — Pyrus communig, TJlmus campestris; central California. In 1916 Baker and Davidson described a species of Eriosoma that attacks the roots of pears throughout the central part of the state, naming it E. pyricola. Later Davidson found that a species common on Ulmus campestris was the alternate form of this species. This elm form checks up very favorably with specimens of E. languinosa Hartig from Europe, and is undoubtedly identical. Thus the name pyricola will have to be dropped in favor of languinosa. These elm galls are of a rather peculiar shape, and, as Patch writes, they have the appear- ance of a bonnet. 150 MISCELLANEOUS STUDIES 44. Genus Mindarus Koch Koch, Die Pflanzenlause, p. 277, 1857. Type M. abietinus n.sp. 176. Mindarus abietinus Koch Koch, Die Pflanzenlause, p. 278, 1857 (orig. desc.). Clarke, Can. Ent., vol. 35, p. 248, 1903. Scliizoneura panwola Thos. (list). Patch, Maine Agr. F.xp. Sta., Bull. 182, p. 242, 1910 (desc.). Eecords. — Pinu-s radiata; Berkeley, Palo Alto (Clarke): Abies cilicia; Stan- ford University, May, 1915. This aphid, easily recognized by the extremely long stigma of the fore wings, has been found in the San Francisco Bay region infesting the shoots of Monterey pine and Cilician fir. Group Vacunina Mordwilko This group contains but two genera, Vacuna Hey den and Glyphina Koch. Mordwilko does not recognize Glyphina, as distinct from Vacuna, although Tullgren does. The latter separates the two genera as follows: 1. Last abdominal tergite formed into a knob-shaped tail. Integument bare, and at most partially set with short lancet-shaped hairs Vacuna Heyd. — Last abdominal tergite half-moon shaped, strongly swollen, but scarcely, if at all, separated from the base. Integument set with stiff bristle-like hairs and in apterous females with grain-like elevations ....Glyphina Koch3* 45. Genus Vacuna Hey den Heyden, Ent. Beitr., vol. 2, p. 289, 1837. Type Aphis dryophila Schrank. 177. Vacuna dryophila (Schrank) (?) Schrank, Fauna Boica, vol. 1, p. 113, 1801. Aphis (orig. desc.). Davidson, Jour. Econ. Ent., vol. 7, p. 128, 1914. Chaitophorus sp. (desc.). Davidson, Jour. Econ. Ent., vol. 10, p. 290, 1917 (desc.). Eecord. — Quercus lobata; Walnut Creek (Davidson). Recently Davidson described this species from specimens taken on valley oak in Contra Costa County, where he had observed it for three years. The single alate female he has taken does not appear identical with European specimens of V. dryophila, so he lists the species under this name provisionally. This genus is not represented in California. A SYNOPSIS OF TEE APHIDIDAE 151 Subfamily Phylloxerinae Dreyfus This subfamily consists of two groups, the Chermisina and the Phylloxerina. Below is a key to these two groups taken from Van der Goot: 1. Body always with wax glands. Antennae of adults three-jointed, seemingly five-jointed, with three large sensoria. Gonapophyses appearing as three short lips. Sexuales dwarfed, with beak Group Chermisina — Body usually without wax glands. Antennae of adults three-jointed, with two large sensoria. Gonapophyses seem to be lacking. Sexuales dwarfed, with- out beak Group Phylloxerina Group Chermisina Borner This group consists of three genera, Pineus Shimmer, Cnapholodes Macq., and Chermes Linn, as it is generally considered, although some authors add more, as Gillettea Del Guercio and Guercioja Mordw. In California but one of these genera is represented, and that by but two species. 46. Genus Chermes Linnaeus Linnaeus, Syst. Nat., vol. 10, 1758. Type Chermes sambuci Linn. 178. Chermes cooleyi Gillette Gillette, Proe. Acad. Nat. Sci. Phila., vol. 69, p. 3, 1907 (orig. desc.). Davidson, Jour. Econ. Ent., vol. 2, p. 299, 1909. C. coweni Gill. (list). Davidson, Jour. Econ. Ent., vol. 3, p. 372, 1910. C. coweni Gill. (list). Brannigan, Mon. Bull. Cal. Comm. Hort., vol. 4, p. 285, 1915 (list). Records. — Pseudotsuga taxi folia, Pinus pinea; San Francisco Bay region, Sac- ramento Valley. This species was first reported in California by Davidson, who found it on Douglas fir at Stanford University. Essig lists it from San Francisco, San Mateo, and Santa Clara counties on Douglas fir. In 1915 it was reported twice, once in Sacramento on Douglas fir, and once on Italian stone pine. The author has specimens from E. J. Vosler taken in Sacramento where it was found infesting the twigs and needles of Italian stone pine. Only the apterous females were present, however. 152 MISCELLANEOUS STUDIES 179. Chermes pinicorticis Fitch Fitch, Trans. N. Y. State Agr. Soc., vol. 14, p. 971, 1855. Coccus (orig. desc.). Storment, 20th Ann. Eep. Illinois St. Ent., appendix, 1898 (desc.). Davidson, Jour. Econ. Ent., vol. 2, p. 299, 1909 (list). Davidson, Jour. Eeon. Ent., vol. 3, p. 372, 1910 (list). Record. — Pinus pinaster maritima; Stanford University (Davidson). This species, which is unknown to the author, was reported as present at Stanford University on Pinus pinaster maritima, where it was so abundant as to sometimes kill the young trees. For a com- plete description see Storment 's paper listed above. Group Phylloxerina Borner There are two genera in this tribe, as considered by Borner and Mordwilko, although the American authors have generally taken cog- nizance of but one, namely, Phylloxera Boyer. Below is a key from Mordwilko to these genera. 1. Neither wingless females nor any other forms secreting any waxy material. Phylloxera Boyer — Wingless females secreting a waxy powder Phylloxerina Borner 47. Genus Phylloxera Boyer Boyer de Fonscolmbe, Ann. Ent. Soc. France, vol. 3, p. 222, 1834. Type P. quercus Boyer. 180. Phylloxera vitifoliae Fitch Fitch, Eept. Ins. N. Y., vol. 1, p. 58, 1855 (orig. desc.). Planchon, C.-E. Aead. Sci. Paris, vol. 67, pp. 588-594, 1868. P. vastatrix (desc.). Clarke, Can. Ent., vol. 35, p. 248, 1903. P. vastatrix Plan (list). Davidson, Jour. Econ. Ent., vol. 2, p. 299, 1909. P. vastatrix Plan. (list). Davidson, Jour. Econ. Ent., vol. 3, p. 372, 1910. P. vastatrix Plan. (list). Records. — Grape; Central and Northern California. This is the only species of this genus reported in California. It is one of the most destructive species of plant lice in this section of the country, having in its time practically wiped out the grape indus- try of Santa Clara Valley, and of many other parts of the state. It seems that in California this species infests the roots only of the grape, the forms that produce the leaf galls in the eastern parts of the country not being found here. A SYNOPSIS OF THE APHIDIDAE 153 48. Genus Phylloxerina Borner Borner, Arbeiter aus d. kais. biol. Anst. f. Land- und Forstwirtschaft, vol. 6, pp. i-v, 81-320, 1908. Type Phylloxera salicis Linn. This genus is represented in California by two species, one found on the stems of cotton wood (Populus sp.) and the other on the stems and exposed roots of willow (Salix sp.). 181. Phylloxerina popularia (Pergande) Pergrande, Proc. Davenport Acad. Sci., vol. 9, p. 266, 1904. Phylloxera (orig. desc.). Davidson, Jour. Econ. Ent., vol. 8, p. 420, 1915. Phylloxera (list). Records. — Populus spp. ; Walnut Creek (Davidson), Merced (Beers). The only report of this species in California is the one of Davidson who found it on Populus fremonti and Populus trichocarpa at Walnut Creek. On October 14, 1915, A. A. Beers of Merced sent some speci- mens to the author from balm of Gilead (Populus balsamifera) in Merced. These were all apterous females, and were found in great masses of white wax on the smaller branches and twigs. These reports are the only ones since its original report from Texas and Louisiana by Pergande. 182. Phylloxrina salicola (Pergande) Pergande, Proe. Davenport Acad. Sci., vol. 9, p. 267, 1904. Phylloxera (orig. desc.). Davidson, Jour. Econ. Ent., vol. 8, p. 419, 1915. Phylloxera (list). Records. — Salix spp.; Walnut Creek (Davidson); Pasadena (Smith). This species was also reported from Walnut Creek by Davidson on arroyo willow (Salix lasiolepis) where he found it on the stems and exposed roots. On October 13, 1915, A. G. Smith sent the author specimens from an ornamental willow (Salix sp.) in Pasadena, where he found it very abundantly that fall. The specimens were all apterous females, and were found in the midst of considerable masses of wax. This species has only been reported from Illinois, District of Columbia, and California. 154 MISCELLANEOUS STUDIES APPENDIX 1 KEYS TO THE GENERA AND TRIBES OF APHIDIDAE BY P. VAN DEE GOOT, 1913 Subfamily APHIDINAE 1. Antennae seven-jointed (better six-jointed). The last true joint with a dis- tinct, more delicate continuation (terminal process). This continuation almost as long as, or even much longer than the last segment; if shorter, the cauda is distinctly wart-shaped, and the number of rudimentary gona- pophyses is always two. Cornicles almost always well formed and clearly projecting. Wings with twice-branched cubitus, only once-branched in exceptional cases 2 — Antennae mostly six-jointed, the last joint with a short projection, this being usually distinctly shorter than half the last segment. Cornicles scarcely projecting, very often only appearing as pores or entirely absent. Wings with a simple or once-branched cubitus 5 2. Cauda wart-like, occasionally not so, or scarcely separated, but then the number of rudimentary gonapophyses is always distinctly two 3 — Cauda sickle-shaped or knobbed, not wart-like, only very seldom absent. Rudi- mentary gonapophyses always three Siphonophorina 3. Cornicles very long, almost cylindrical. Rudimentary gonapophyses three. Drepanosiphina — Cornicles very short, somewhat clubbed. Rudimentary gonapophyses two or four 4 4. Number of rudimentary gonapophyses four. Body never with long clubbed hairs Chaitophorina — Number of rudimentary gonapophyses two. Body often with knobbed hairs. Tarsi always with two pulvillae [Haftlappchen] Callipterina 5. Cauda wart-like 6 — Cauda not wart-like, usually absent 7 6. Anal plate bilobed. Sensoria of alate females linear Hormaphidlna — Anal plate simple. Sensoria of alate females circular Vacunina p.p. 7. Cauda distinctly sickle-shaped Mindarina — Cauda only scarcely or not at all separated 8 8. Antennae five-jointed. Cornicles very short, only slightly projecting. Body without distinct wax gland groups Vacunina p.p. — Antennae six-jointed, those of the apterous forms often only four- or five- jointed. Cornicles often only pores or entirely lacking. Body often with wax gland 9 9. Body with long, mostly fine hairs; without distinctly facetted wax gland plates. Primary sensoria almost always, without hairy edges 10 — Body naked; very often with distinctly facetted wax-gland plates. Primary sensoria often with hairy edges 11 10. Rudimentary gonapophyses three. Wings mostly with twice-branched cubitus. Cornicles always prominent Lachnina — Rudimentary gonapophyses none. Wings with simple or once-branched cubitus. Cornicles often absent ... ....Anoeciina A SYNOPSIS OF THE APHIDIDAE 155 11. Eudimentary gonapophyses three. Facets of wax-gland plates almost equal- sized. Wings with simple cubitus. Sensoria of alate forms long oval, not linear Pemphlgina — Eudimentary gonapophyses none. Wax gland plates always with at least one large central facet. Sensoria of alate forms linear. Wings with simple or once-branched cubitus Schizoneurina Subfamily CHEEMISINAE 1. Eudimentary gonapophyses appearing as three short cones. Wax glands almost always present Chennisina — Eudimentary gonapophyses seemingly lacking. Wax glands mostly absent. Phylloxerina Group SlPHONOPHORINA 1. Apterous forms with a few sensoria on the third antenual segment. Antennal tubercles usually well formed. Body almost never with lateral tubercles, in any case these are never formed on the seventh abdominal segment .... 2 — Apterous forms without sensoria on the third antennal segment. Antennal tubercles often small or absent. Body with lateral tubercles 4 2. Cornicles almost cylindrical, or rarely somewhat swollen on the side, but then the body is covered with capitate hairs 3 — Cornicles distinctly clavate. Body almost bare, never with capitate hairs. Rhopalosiphum Koch Type Amphorophora ampullata Buckton. 3. Body of apterous forms with long capitate hairs. First antennal joint drawn out, somewhat tooth-shaped on the inner side Myzus Passerini Type Aphis ribis Linn. — Body of apterous forms bare or without capitate hairs. First antennal joint never drawn out, tooth-like Macrosiphum Passerini Type Aphis millifolii Fabr. 4. Body of apterous forms with capitate hairs. First antennal joint more or less toothed on inner side Capitophorus n.gn. Type Phorodon carduinum Walker. — Body of apterous forms without capitate hairs. First anteunal joint not toothed 5 5. Body with many long delicate hairs. Cornicles short, somewhat swollen. Cladobius (Koch.) Pass. Type Aphis populea Kalt. — Body bare or almost so 6 6. Cornicles almost as long or longer than cauda 7 — Cornicles much shorter than cauda 16 7. Cornicles always distinctly clavate Siphocoryne Pass. Type Aphis avenae Fabr. — Cornicles cylindrical or conical 8 8. Antennal tubercles well formed, very distinctly toothed on the inner side. Tubercles on the side of the body always absent 9 — Antennal tubercles mostly small or lacking, never distinctly toothed. Body often with lateral tubercles 10 9. Antennal tubercles very strongly toothed, the first joint being distinctly toothed on the inner side Phorodon Pass. Type Aphis humuli Schr. — Antennal tubercles only slightly toothed, first antennal joint being rounded or flat on the inner side, never toothed Ovatus n.gn. Type Ovatus mespili v. d. G. 156 MISCELLANEOUS STUDIES 10. Antennal tubercles well formed, strongly rounded on the inner side. Typo Aphis cerasi Fabr. Myzoides n.gn. — Antennal tubercles small or lacking, never drawn out distinctly on inner side 11 11. Body with small tubercles on the middle of the seventh and eighth abdominal segments, and often also on the head and prothorax Dentatus n.gn. Type Aphis sorbi Kalt. — Body without tubercles on the middle of the seventh and eighth abdominal segments 12 12. Cubitus of fore wing only once-branched Toxoptera Koch Type Toxoptera graminum (Bond.). — Cubitus of fore wing always twice-branched. Body often with lateral tuber- cles 13 13. Cornicles short, always distinctly conical. Cauda very short, broaa with rounded- tip, usually approximately the length of the cornicles, or entirely lacking. Lateral tubercles lacking or only indistinctly formed on the an- terior abdominal segments 15 — Cornicles long, almost cylindrical. Cauda sickle- or club-shaped, usually dis- tinctly shorter than cornicles 14 14. Body long without lateral tubercles. Front often with a very distinct tubercle in the middle Myzaphls n.gn. Type Aphis rosarum Walker. — Body more rounded, with lateral tubercles. Front usually flat, never with a distinct tubercle Aphis Linn. Type Aphis rumicis Linn. 15. Cauda distinctly separated, almost as long as broad Brachycaudus n.gn. Type Aphis myosotidis Koch. (Aphis cardui Linn, belongs in this genus.) — Cauda lacking or scarcely separated, much shorter than broad ....Acaudus n.gn. Type Aphis lychnidis Linn. 16. Cornicles distinctly longer than broad. Cauda usually not conical 17 — Cornicles extremely short, scarcely projecting, cylindrical, usually nearly as long as broad. Cauda always conical with broad base 19 17. Cornicles only a little longer than broad, distinctly conical. Cauda sickle- or club-shaped Longicaudis n.gn. •Type Hyalopterus trirhodus (Walker). — Cornicles cylindrical, at least twice as long as broad 18 18. Body with lateral tubercles on first and seventh abdominal segments. Cauda small, club-shaped Hyalopterus Koch Type Aphis pruni Fabr. — Body without lateral tubercles on first and seventh abdominal segments. Cauda conical Serniaphis n.gn. Type Aphis carotae Koch. 19. Body long, without lateral tubercles. Antennae short, at the most about half the length of the body Brachycolus Buckton Type Brachycolus stellariae (Hardy). — Body oval with lateral tubercles on prothorax, first and seventh abdominal segments. Antennae at least about three-fourths as long as the body. Type Aphis thalittri Koch. Brachysiphum n.gn. Group DREPANOSIPHINA Genus Drepanosiphum Koch. Type Drepanosiphum platanoides Schrank. A SYNOPSIS OF THE APHIDIDAE 157 Group CALLIPTERINA 1. Antennae six-jointed. Cornicles merely pores. Body always with wax glands Phyllaphis Koch Type Phyllaphis fagi (Linn.). — Antennae seven-jointed, the terminal process at least one-half as long as the preceding joint. Cornicles always distinctly projecting. Body almost always without wax glands, these always of similar shape 2 2. Seventh antennal joint distinctly longer than sixth 3 — Seventh antennal joint only as long as, or shorter than sixth 6 3. Cornicles but slightly projecting. Antennae curved as in beetles. Bradyaphis Mord. Type Bradyaphis antennata (Kalt.). — Cornicles distinctly prominent. Antennae straight 4 4. Anal plate only slightly emarginate, never bilobed. Body with tolerably stiff hairs, these are never capitate. Apterous forms always with sensoria on third antennal joint Callipterinella n.gn. Type Callipterus betularius Kalt. — Anal plate distinctly bilobed. Body bare or with capitate hairs 5 5. Apterous forms without sensoria on third antennal joint. The body always with capitate hairs Callipterus Koch Type Callipterus coryli (Goetze). — Apterous forms with a few sensoria on third antennal joint. Body with dis- tinct tubercles Tuberculatus Mord. Type Tuberculatus "betulicolus (Kalt.). 6. Anal plate distinctly bilobed 3 — Anal plate always simple 7 7. Cauda wart-like, distinctly separated from base. Apterous forms without sensoria on third antennal joint Callipteroides Mord. Type Callipterus betulae Koch. — Cauda scarcely visible. Sensoria present on third antennal joint of apterous forms Symydobius Mord. Type Symydobius oblongus (Hey den). 8. Seventh antennal joint nearly as long as the sixth. Wings Avith only very small black spots at the tip of the veins Subcallipterus Mord. Type Callipterus alni (Fabr.). — Seventh antennal joint nearly half as long as sixth. Wings black spotted. Pterocallis Pass. Type Pterocallis tiliae (Linn.). Group CHAITOPHORINA 1. Body with long delicate hairs. Antennae seven-jointed. Cornicles well de- veloped 2 — Body with short thorn-like hairs. Antennae six-jointed, the terminal process always distinctly longer than the preceding joint. Cornicles only slightly projecting Sipha Passerini Type Sipha glyceriae (Kalt.). 2. Tarsi with two " Haftlappchen " [i.e., the empodial hair is spatula-like]. Chaitophorinella n.gn. Type Chaitophorus testudinatus (Thornton). — Tarsi without "Haftlappchen" [i.e. the empodial hair is bristle-like]. Chaitophorus Koch Type Chaitophorus leucomelas Koch. 158 MISCELLANEOUS STUDIES Group LACHNINA 1. Wings usually with twice-branched cubitus, the radius always straight. Cauda not at all or only slightly separated Lachnus 111. Type Lachnus juniperi De Geer. — Wings with once- or twice-branchel cubitus and with a curved radius ; the mem- brane usually with dusky markings. Cauda usually slightly separated 2 2. Beak distinctly longer than the body, strongly retractile. Cubitus but once- branched, the wings only slightly darkened Stomapnis Buckton Type Stomaphis quercus (Linn.). — Beak clearly shorter than body and only slightly retractile. Wings beautifully spotted with dark brown 3 3. Cubitus twice-branched Dryobius Koch Type Dryobius croaticus Koch. — Cubitus once-branched Schizodryobius n.gn. Type Lachnus exsiccator Hart. Tribe ANOECIINA 1. Hind tarsi elongate Trama Heyden Type Trama radicis Koch. — Hind tarsi not elongate 2 2. Cubitus once-branched. Cornicles present, quite prominent. Margin of body with peculiar non-faceted "wax-gland" (?) plates Anoecia Koch Type Anoecia corni (Fabr.). — Cubitus not branched. Cornicles absent. Wax gland plates not present. Tullgrenia v. d. G. Type Tullgrenia phaseoli (Pass.). Tribe HOEMAPHIDINA 1. Antennae always five-segmented. The fronds almost without exception with two little horns. Cubitus once branched Cerataphis Licht. Type C. lataniae Boisd. — Antennae of the apterae often only three-segmented. Fronds without protuber- ances. Cubitus simple Hamamelistes Schim. Type H. betulae Mordw. A SYNOPSIS OF THE APHIDIDAE 159 APPENDIX 2 HOST PLANT LIST OF CALIFORNIA APHIDIDAE35 Abies (fir) 45. Lachnus ferrisi Swain 47. Laclinus occidentalis Dvdn. 176. Mindarus abietinus Koch Abutilon (Indian mallow) 146. Aphis senecio Swain 104. Rhopalosiphum persicae (Sulz.) Acer (maple, box elder) 5. Drepanaphis acerifolii (Thomas) 4. Drepanosiphum platanoides (Schrank) 33. Thomasia negundinis (Thomas) Achittea (yarrow) 79. Macrosiphum solanifolii (Ashmead) Aegopodium (goutweed) 108. Siphocoryne capreae (Fabr.) Aesculus (California buckeye) 88. Mysus circumflexus (Buckton) 171. Prociphilus venafuscus Patch Alder, see Alnus Alfalfa, see Medicago Alfilerilla, see Erodium Alisma (water plantain) 156. Siphocoryne nymphaeae (Linn.) Almond, see Prunus Alnus (Alder) 9. Eucallipterus flava (Davidson) 8. Euceraphis gillettei Davidson 11. Myzocallis alnifoliae (Fitch) Alopecurus (foxtail) 68. Macrosiphum granarium (Kirby) 88. Myzus circumflexus (Buekton) Althaea (hollyhock) 121. Aphis euonomi Fabr. Alum root, see Heuchera 35 In the following list only the generic and common names of the plants are employed, the various species of plants being omitted. Although in certain cases aphids are restricted to certain species, as Eriosoma languinosa Hartig on Pyrus communis but not en Pyrus malus, these are in the minority. The botanical names are taken from the following works, with preference as in the order listed : Bailey, L. H., Standard cyclopedia of horticulture, vols. 1-6, New York, Mac- millan, 1914-1917. Bobinson, B. L., and Fernald, M. L., Gray's New manual of botany, ed. 7, Cambridge, Harvard University, 1908. Jepson, W. L., A flora of western middle California, ed. 2, San Francisco, Cun- ningham, 1911. Abrams, LeEoy, Flora of Los Angeles and vicinity, Palo Alto, Stanford Uni- versity Press, 1904. 160 MISCELLANEOUS STUDIES Amaranthus (pigweed) 123. Aphis gossypii Glover 132. Aphis middletonii Thomas 104. Bhopalosiphum persicae (Sulz) 163. Trifidaphis radicicola (Essig) Ambrosia (ragweed) 146. Aphis senecio Swain 77. Macrosiphum rudbeckiae (Fitch) Ampelodesma 68. Macrosiphum granarium (Kirby) Amsinckia (amsinckia) 146. Aphis senecio Swain 104. Bhopalosiphum persicae (Sulz.) Angelica (angelica) 109. Aphis angelicae Koch 115. Aphis cari Essig 108. Siphocoryne capreae (Fabr.) Anise, Wild, see Carum Anthemis (chamomile) 121. Aphis euonomi Fabr. 146. Aphis senecio Swain 123. Aphis gossypii Glover Apple, see Pyrus Apricot, see Prunus Aquilegia (columbine) 85. Myzus aquilegiae Essig Arbor vitae, see Thuja sp. Arbutus (madrone, strawberry tree) 103. Rhopalosiphum nervatum Gillette Arctostaphylos (manzanita) 1. Phyllaphis coweni (Cockerell) 103. Bhopalosiphum nervatum Gillette Artemisia (sagebrush, oldman, California mugwort, etc.) 122. Aphis frigidae Oestlund 131. Aphis medicaginis Koch 137. Aphis oregonensis Wilson 146. Aphis senecio Swain 61. Macrosiphum artemisiae (Fonsc.) 62. Macrosiphum artemisioola (Williams) 72. Macrosiphum ludovicianiae (Oestlund) Artichoke, see Cynara Arundinaria (bamboo) 12. Myzocallis arundicolens (Clarke) 13. Mysocallis arundinariae Essig Arundo (giant reed) 12. Mysocallis arundicolens (Clarke) 13. Mysocallis arundinariae Essig Asclepias (milkweed) 123. Aphte gossypii Glover 135. Aphis nerii Fonsc. 102. Bhopalosiphum lactucae (Kalt.) A SYNOPSIS OF THE APH1DIDAE 161 Ash, see Fraxinus Arparagus (asparagus, smilax, asparagus fern) 123. Aphis gossypii Glover 88. Myzus circumflexus (Buckton) Aster (aster) 132. Aphis middletonii Thomas 146. Aphis senccio Swain Astragalus (loco weed) 131. Aphis medicaginis Koch Atriplex (oraehe) 147. Aphis tetrapteralis Cockerell 79. Macrosiphum solanifolii (Ashmead) Avocado, see Persea Avena (oats) 111. Aphis avenae Fabr. 68. Macrosiphum granarium (Kirby) 105. Rhopalosiphum rhois Monell Baccharis ( groundsel ) 146. Aphis senecio Swain 63. Macrosiphum baccharadis (Clarke) 77. Macrosiphum rudbeckiae (Fitch) 104. Rhopalosiphum persicae (Sulz.) Bamboo, see Arundinaria, Bambusa, and Phyllostachys Bambusa (bamboo) 12. Myzocallls arundicolens (Clarke) Banana, see Musa Barberry, see Berberis Barley, see Hordeum Basswood, see Tilia Bean, see Pliaseolus Bean, Blackeye, see Vigna Bean, Broad, see Vicia Beech, see Fagus Beet, see Beta Begonia (begonia) 123. Aphis gossypii Glover Bell, fairy, see Dipsorum Berberis (barberry) 154. Liosomaphis berberidis (Kalt.) Beta (beet, sugarbeet) 124. Aphis gossypii Glover 164. Pemphigus betae Doane Betula (birch) 6. Calaphis betulaecolens (Fitch) 27. Callipterinella annulata (Koch) 7. Euceraphis betulae (Koch) Birch, see Betula Blackberry, see Rubus Bougainvillea (bougainvillea) 104. Rhopalosiphum persicae (Sulz.) Boxelder, see Acer 162 MISCELLANEOUS STUDIES Brassica (cabbage, mustard, turnip, etc.) 112. Aphis brassicae Linn. 144. Aphis pseudobrassicae Davis 166. Pemphigus populi-transversus Riley (?) 102. Rhopalosiphum lactucae (Kalt.) 104. Rhopalosiphum persicae (Sulz.) Broom, see Cytisus Buckeye, California, see Aesculus Buckton, see Rhamnus Bur clover, see Medicago Buttercup, see Ranunculus Cabbage, see Brassica Calendula (marigold) 113. Aphis calendulicola Monell 121. Aphis euonomi Fabr. 146. Aphis senecio Swain California buckeye, see Aesculus California holly, see Heteromeles California mugwort, see Artemesia California poppy, see Esclischoltsia California sagebrush, see Artemisia California tule, see Typlia Calla, see Zantcdesohia Camellia (camellia) 152. Toxoptera aurantii (Fonsc.) Canary grass, see Phalaris Cantaloupe, see Cucumis Capsella (shepard's purse) 112. Aphis brassicae Linn. 123. Aphis gossypii Glover 141. Aphis pseudobrassicae Davis 104. Rhopalosiphum persicae (Sulz.) Capsicum (pepper pimento) 104. Rhopalosiphum persicae (Sulz.) Caragana (pea tree) 131. Aphis medicaginis Koch. Carum (wild anise) 115. Aphis cari Essig 155. Siphocoryne capreae (Fabr.) Castanea (chestnut) 15. Myzocallis castanicola Baker (davidsoni Swain) Catalpa (catalpa) 123. Aphis gossypii Glover 139. Aphis pomi de Geer 104. Rhopalosiphum persicae (Sulz.) Cauliflower, see Brassica Ceanothus (mountain lilac) 116. Aphis ceanothi Clarke Centaurea (tacalote) 130. Aphis marutae Oestlund Centranthus (red valerian) 76. Macrosiphum rosae (Linn.) 104. Rhopalosiphum persicae (Sulz.) A SYNOPSIS OF THE APHIDIDAE 163 Chaerophyllum 155. Siphocoryne capreae (Fabr.) Chamomile, see Anthemis Chaparral broom, see Baccharis Charlock, see Brassica Cheeseweed, see Malva Cheiranthus (wallflower) 88. Myzus circumflexus (Buckton) Chenopodium (lamb's-quarters, pigweed) 110. Aphis atriplicis Linn. 123. Aphis gossypii Glover 124. Aphis hederae Kalt. ( ?) 164. Pemphigus betae Doane (?) 104. Rhopalosiphum persicae (Sulz.) Cherry, see Prunus Cherry, wild, see Prunus Chestnut, see Castanea Chestnut, Horse, see Aesculus Chicory, see Chicorium Christmas berry, see Heteromeles Chrysanthemum (chrysanthemum) 56. Amphorophora latysiphon Davidson 123. Aphis gossypii Glover 146. Aphis senecio Swain 160. Coloradoa rufomaculata Wilson 77. Macrosiphum rudbeckiae (Fitch) 78. Macrosiphum sariborni Gillette Cichorium (chicory) 71. Macrosiphum lactucae (Kalt.) Cicuta (water hemlock) 155. Siphocoryne capreae (Fabr.) Cirsium (thistle) 144. Aphis cardui Linn. Citrullus (watermelon) 123. Aphis gossypii Glover Citrus (citrus, orange, lemon, etc.) 118. Aphis cooM Essig 123. Aphis gossypii Glover 131. Aphis medicaginis Koch 79. Macrosiphum solanifolii (Ashmead) 104. Rhopalosiphum persicae (Sulz.) 152. Toxoptera aurantii (Fonsc.) Clarkia (clarkia) 104. Rhopalosiphum persicae (Sulz.) Clematis (clematis) 94. Myzus varians Davidson Clover, see Trifolium Clover, Sweet, see Melilotus Coffeeberry, see Rhamnus Columbine, see Aquilegia Compositae (various species) 131. Aphis medicaginis Koch 65. Macrosiphum chrysanthemi (Oestlund) 77. Macrosiphum rudbeckiae (Fitch) 164 MISCELLANEOUS STUDIES Conium (poison hemlock) 159. Siplwcoryne pastinacae (Linn.) Convolvulus (morning glory) 56. Amphorophora latysiplwn Davidson 123. Aphis gossypii Glover 72. Macrosiphum ludovicianae (Oestlund) Corn, see Zea Cornus (dogwood) 119. Aphis cornifoliae Fitch 123. Aphis gossypii Glover Corylus (hazelnut) 16. Mysocallis coryli (Goetze) 100. Bhopalosiphum corylinum Davidson Cotoneaster (cotoneaster) 139. Aphis pomi de Geer Cotton, see Gossypium Cottonwood, see Populus Cow parsnip, see Heracleum Cowpea, see Vigna Cowslip, see Primula Crab apple, see Pyrus Cranesbill, see Geranium Crataegus (hawthorn) 120. Aphis crataegifoliae Fitch 139. Aphis pomi de Geer Cruciferae (various spp.) 112. Aphis brassicae Linn. 141. Aphis pseudobrassicae Davis Cucumber, see Cucumis Cucumis (cucumber, muskmelon, cantaloupe, etc.) 123. Aphis gossypii Glover Cucurbita (squash, gourd, pumpkin, etc.) 123. Aphis gossypii Glover 66. Macrosiphum cucurbitae (Thomas) Cupressus (cypress) 161. Cerosipha cupressi Swain 96. Macrosiphum morrisoni Swain Currant, see Eibes Cydonia (quince) 139. Aphis pomi De Geer Cynara (artichoke) 86. Myzus braggii Gillette Cynoglossum ( houndstongue ) 104. Elwpalosiphum persicae (Sulz.) Cypress, see Cupressus Cyrtomium (holly fern) 162. Cerataphis lataniae (Boisd.) 58. Idiopterus nephrelepidis Davis 88. Myzus circumflexus (Buckton) Cytisus (broom) 146. Aphis senecio Swain 104. Ehopalosiphum persicae (Sulz.) A SYNOPSIS OF THE APHIDIDAE 165 Dandelion, see Taraxacum Datura (jimson weed) 123. Aphi# gossypii Glover Deinandra 79. Macrosiplmm solanifolii (Ashmead) Digitalis (foxglove) 88. Myzus circumflexus (Buckton) Dipsacus (fuller's teasel) 7G. Macrosiphum rosae (Linn.) 77. Macrosiphum rudbeckiae (Fitch) 104. Ehopalosiphum persicae (Sulz.) Disporum (fairy bell) 79. Macrosiphum solanifolii (Ashmead) Dock, see Rumex Dogwood, see Cornus Douglas fir, see Pseudotsuga Dracaena (dragon tree) 111. Aphis avenae Fabr. Dragon tree, see Dracaena Eldei berry, see Sambucus Elm, see Ulmus Elymus (wild rye) 68. Macrosiphum granarium (Kirby) English ivy, see Hedera Epilobium (fireweed) 136. Aphis oenotherae Oestlund Eriobotrya (loquat) 139. Aphis pomi de Geer Erodium (alfilerilla) 79. Macrosiphum solanifolii (Ashmead) 104. Ehopalosiphum persicae (Sulz.) Erysimum (western wallflower) 155. Siphocoryne capreae (Fabr.) Escallonia (escallonia) 104. Ehopalosiphum persicae (Sulz.) Eschscholtzia (California poppy) 123. Aphis gossypii Glover Everlasting, see Gnaphalium Fagus (beech) 2. Phyllaphis fagi (Linn.) Fairybell, see Dipsorum Fennel, see Foeniculum Fenugreek, see Trigonella Fern, asparagus, see Asparagus Fern, Boston, see Nephrolepis Fern, holly, see Cyrtomium Fig marigold, see Mesembryanthemum Figwort, see Scrophularia Fir, see Abies Fir, Douglas, see Pseudotsuga Fireweed, see Epilobium Foeniculum (fennel) 155. Siphocoryne capreae (Fabr.) 166 MISCELLANEOUS STUDIES Foxglove, see Digitalis Foxtail, see Alopecurus Fragaria (strawberry) 90. Myzus fragaefolii Cockerell Fraxinus (ash) 171. Prociphilus venafuscus Patch 167. Thecabius californicus (Davidson) Fuller's teasel, see Dipsacus Fuchsia (fuchsia) 79. Macrosiphum solanifolii (Ashmead) 88. Myzus circumflexus (Buckton) Gambleweed, see Sanicula Geranium, see Pelargonium Geranium (cranesbill) 104. Rhopalosiphum persicae (Sulz.) German ivy, see Senecio Gladiolus (gladiolus) 88. Myzus circumflexus (Buckton) Glycyrrhiza (liquorice) 131. Aphis medicaginis Koch Gnaphalium (everlasting) 146. Aphis senecio Swain 60. Macrosiphum ambrosiae (Thomas) Gooseberry, see Ribes Goosefoot, see Chenopodium Gossypium (cotton) 123. Aphis gossypii Glover Gourd, see Cucurbita Goutweed, see Aegopodium Graminaceae (various species) 111. Aphis avenae Fabr. 67. Macrosiphum dirhodum (Walker) 68. Macrosiphum granarium (Kirby) 105. Rhopalosiphum rhois Monell Grape, see Vitis Grindelia (marsh grindelia) 146. Aphis senecio Swain Hawthorn, see Crataegus Hazelnut, see Corylus Hcdera (English ivy) 109. Aphis angelicae Koch 124. Aphis hederae Kalt 104. Rhopalosiphum persicae (Sulz.) Hedge mustard, see Sisymbrium Hedge nettle, see Stachys Helianthus (sunflower) 123. Aphis gossypii Glover 132. Aphis middletonii Thomas 146. Aphis senecio Swain 60. Macrosiphum ambrosiae (Thomas) 77. Macrosiphum rudbeckiae (Fitch) 104. Rhopalosiphum persicae (Sulz.) A SYNOPSIS OF THE APHIDIDAE 167 Hemlock, Poison, see Conium Hemlock, Water, see Cicuta Heracleum (cow parsnip) 123. Aphis gossypii Glover 125. Aphis heraclei Cowen Heteromeles (California holly, Christmas berry) 170. Prociphilus alnifoliae (Williams) 103. Ehopalosiphum nervatum Gillette Heuchera (alum root) 69. Macrosiphum heucherae (Thomas) Hibiscus (rose mallow) 121. Aphis euonomi Fabr. Holly fern, see Cyrtonium Hollyhock, see Althaea Holly, mountain, see Heteromeles Honey flower, see Melianthus Honeysuckle, see Lonicera Hop, see Humulus Hordeum (barley) 111. Aphis avenae Fabr. 68. Macrosiphum granarium (Kirby) Houndstongue, see Cynoglossum Humulus (hop) 123. Aphis gossypii Glover 98. Phorodon humuli (Schrank) Hydrangea (hydrangea) 123. Aphis gossypii Glover Indian mallow, see Abutilon Ironweed, see Veronina Ivy, Engislh, see Hedera Ivy, German, see Senecio Jasminum (jessamine) 70. Macrosiphum jasmini (Clarke) Jessamine, see Jasminum Jimpson weed, see Datura Juglans (walnut) 24. Callipterus calif ornicus (Essig) 25. Callipterus caryae Monell 23. Chromaphis juglandicola (Kalt.) 26. Monellia caryella (Fitch) Knotweed, see Polygonum Lactuca (lettuce) 79. Macrosiphum solanifolii (Ashmead) Lamb 's-quarters, see Chenopodium Lathyrus (sweet pea) 74. Macrosiphum pisi (Kalt.) Laurel, see Laurus Laurel, California, see Umbellularia Laurestinus, see Viburnum Laurus (laurel) 150. Aphis viburnicolens n.sp. 168 MISCELLANEOUS STUDIES Lavatcra (tree mallow) 104. Khopalosiphum persicae (Sulz.) Leather root, see Psorales Lemon, see Citrus Lcpidium (peppergrass) 123. Aphis gossypii Glover Lettuce, see Lactuca Ligusticum (lovage) 155. Siphocorync capreae (Fabr.) Lilac, see Syringa Lilac, Mountain, see Ceanothus Lilium (lily) 123. Aphis gossypii Glover 88. Myzus circumflexus (Buekton) Lily, see Lilium Lily, Water, see Nymphaea Linden, see Tilia Liquorice, see Glycyrrhiza Liriodendron (tulip tree) 104. Bhopalosiphum persicae (Sulz.) Lithospermum 127. Aphis lithospermi Wilson Loco weed, see Astragalus Locust, see Bobinia Loganberry, see Bubus Lonicera (honeysuckle) 157. Siphocoryne pastinacae (Linn.) Loquat, see Eriobotrya Lovage, see Ligusticum Lupinus (lupine) 59. Macrosiphum albifrons Essig Lycopersicum (tomato) 91. Myzus lycopersicae (Clarke) 104. Bhopalosiphum persicae (Sulz.) Madia (tarweed) 77a. Macrosiphum rudbeclciae '(Fitch) var. madia n.var. Madron, see Arbutus Mallow, Indian, see Abutilon Mallow, Rose, see Hibiscus Mallow tree, see Lavatera Malva (cheeseweed) 121. Aphis euonomi Fabr. 123. Aphis gossypii Glover 104. Bhopalosiphum persicae (Sulz.) Manzanita, see Arctostaphylos Maple, see Acer Marigold, see Calendula, Marigold, fig, see Mescmbryanthemum Matthiola (ten-weeks' stock) 141. Aphis pseudobrassicae Davis Mayten, see Maytenus Maytenus (mayten) 121. Aphis euonomi Fabr. A SYNOPSIS OF THE APHIDIDAE 169 Medicago (alfalfa, bur clover, etc.) 131. Aphis medicaginis Koch 74. Macrosiphum pisi (Kalt.) Melianthus (honey flower) 104. Bhopalosiphum persicae (Sulz.) Melilotus (sweet clover) 131. Aphis medicaginis Koch Mesembryanthemum (fig marigold) 121. Aphis euonomi Fabr. • Milk thistle, see Silybum Milkweed, see Asclepias Morning glory, see Convolvulus Morus (mulberry) 133. Aphis mori Clarke Mountain holly, see Heteromeles Mountain lilac, see Ceanothus Mugwort, California, see Artemisia Mulberry, see Morus Musa (banana) 111. Aphis avenae Fabr. Muskmelon, see Cucumis Mustard, see Brassica Mustard, Hedge, see Sisymbrium Mustard, Teasel, see Erysimum Nasturtium, see Tropaeolum Nectarine, see Prunus Nephrolcpis (Boston fern) 58. Idiopterus nephrelepidis Davis Nerium (oleander) 135. Aphis nerii Fonsc. Nettle, Hedge, see Stachys Nettle, Stinging, see Urtica Nightshade, see Solanum Ninebark, see Physocarpus Nymphaea (water lily) 123. Aphis gossypii Glover 156. Siplwcoryne nymphaeae (Linn.) Oak, see Quercus Oak, Poison, see Ehus Oak, Tanbark, see Pasania Oats, see Avena Oenothera (evening primrose) 136. Aphis oenotherae Oestlund Oldman, see Artemisia Oleander, see Nerium Orange, see Citrus Orache, see Atriplex Orchidaceae (orchids) 162. CeratapJns lataniae (Boisd.) Orthocarpus (owl clover) 73. Macrosiphum orthocarpi Davidson Owl clover, see Orthocarpus 170 MISCELLANEOUS STUDIES Oxalis (oxalis) 97. Macrosiphum solanifolii (Ashmead) 104. Rhopalosiphum persicae (Sulz.) 152. Toxoptera aurantii (Fonsc.) Pansy, see Viola Papaver (poppy) 121. Aphis euonomi Fabr. (papaveris Fabr.?) Parsley, see Petroselinum Parsnip, see Pastinaca Parsnip, Cow, see Heracleum Pasania (tanbark oak) 20. Myzocallis pasaniae Davidson Pastinaca (parsnip) 156. Siphocoryne pastinacae (Linn.) Pea, see Pisum Pea, Cow, see Vigna Pea, Sweet, see Lathyrus Pea tree, see Caragona Peach, see Prunus Pear, see Pyrus Pelargonium (geranium) 97. Pentalonia nigronervosa Coquellet 104. Rhopalosiphum persicae (Sulz.) Pentstemon (pentstemon) 88. Myzus circumftexus (Buckton) 104. Rhopalosiphum persicae (Sulz.) Pepper, see Capsicum Peppergrass, see Lepidium Periwinkle, see Vinca Per sea (avacado) 123. Aphis gossypii Glover Petroselinum (parsley) 155. Siplwcoryne capreae (Fabr.) Phalaris (canary grass) 111. Aphis avenae Fabr. 153. Hyalopterus arundinis (Fabr.) Phaseolus (bean) 121. Aphis euonomi Fabr. (rumicis Linn.?) 131. Aphis medicaginis Koch 74. Macrosiphum pm (Kalt.) Phragmites (reed grass) 153. Hyalopterus arundinis (Fabr.) Phyllostachys (bamboo) 12. Myzocallis arundicolens (Clarke) Physocarpus (ninebark) 100. Rhopalosiphum corylinum Davidson Pice a (spruce) 46. Lachnus glehnus Essig 55. Lachnus vanduzei n.sp. 158. Myzapliis abietina (Walker) Pigweed, see Amaranthus, and Chenopodium Pimento, see Capsiwm A SYNOPSIS OF THE APHIDIDAE 171 Pimpinella 155. Siphocoryne capreae (Fabr.) Pine, see Pinus Pinus (pine) 178. Chermes cooleyi Gillette 179. Chermes pinicorticis Fitch 43. Essigella californica (Essig) 45. Laclmus ferrisi Swain 48. Lachnus oregonensis Wilson 49. Lachnus pini-radiatae Davidson 50. Lachnus .ponderosa Williams 52. Lachnus sabinianus n.sp. 53a. Lachnus tomentosa (De Geer) (Addenda) 176. Mindarus abietinus Koch Pisum (pea) 74. Macrosiphum pisi (Kalt.) Pittosporum (pittosporum) 139. Aphis pomi De Geer 79. Macrosiphum solanifolii (Ashmead) 104. Jlhopalosii>hum persicae (Sulz.) Plantago (plantain) 123. Aphis gossypii Glover 129. Aphis malifoliae Fitch (?) 88. Hyzus circumflexus (Buckton) Plantain, see Plantago Plantain, Water, see Alisma Plat anus (western sycamore) 4. Drepanosiphum platanoides (Schrank) Plum, see Prunus Polygonum (knotweed) 100. Rhopalosiphum hippophaes (Koch). 156. Siphocoryne nymphaeae (Linn.) Pomegranate, see Punica Pondweed, see Potamogeton Poplar, see Populus Poppy, see Papaver Poppy, California, see Eschscholtzia Populus (poplar, cottonwood) 28. Arctaphis populifolii (Essig) 164. Pemphigus bctae Doane 165. Pemphigus populi-caulis Fitch 166. Pemphigus populi-transversus Eiley 181. Phylloxerina popularia (Pergande) 40. Ptcrocomma populifoliae (Fitch) 167. Thecabius calif ornicus (Davidson) 168. Thecabius populiconduplifolius (Cowen) 169. Thecabius populi-monilis (Eiley) 34. Thomasia populicola (Thomas) 35. Thomasia salicola (Essig) Potamogeton (pondweed) 156. Siphocoryne nymphaeae (Linn.) Potato, see Solarum 172 MISCELLANEOUS STUDIES Primrose, Evening, see Oenothera Primula (cowslip) 56. Amphorophora latysiphon Davidson Prune, see Prunus Prunus (almond, apricot, cherry, nectarine, peach, plum, prune) 107. Aphis alamedensis Clarke 114. Aphis cardui Linn. 117. Aphis cerasifoliae Fitch 138. Aphis persicae-niger Smith 140. Aphis prunorum Dobr. 153. Eyalopterus arundinis (Fabr. 87. Myzus cerasi (Fabr.) 98. Phorodon humuli (Schrank) 104. Bhopalosiphum persicae (Sulz.) 156. Siphocoryne nymphaeae (Linn.) Pseudotsuga (Douglas fir) 178. Chermes cooleyi Gillette 43. Essigella californica (Essig) 51. Lachnus pseudotsuga Wilson 53. Lachnus taxifolia Swain 171. Prociphilus venafuscus Patch Psorales (leather root) 74. Macrosiphum pisi (Kalt.) Pteris (brake) 75. Macrosiphum pteridis Wilson Punica (pomegranate) 123. Aphis gossypii Glover Pumpkin, see Cucur~blta Pyrus (apple, pear) 123. Aphis gossypii Glover 129. Aphis malifoliae Fitch 139. Aphis pomi De Geer 175. Eriosoma languinosa Hartig (pyricola B. & D.) 174. Eriosoma lanigerum (Hausman) Quercus (oak) 5. Drepanaphis acerifolii (Fitch) (T) 14. Myzocallis bellus (Walsh) 15. Myzocallis castanicola Baker (davidsoni Swain) 17. Myzocallis discolor (Monell) 18. Myzocallis punctatus (Monell) 19. Myzocallis californicus Baker (maureri Swain) 21. Myzocallis quercus (Kalt.) 3. Phyllaphis quercicola Baker 36. Symydobius agrifoliae Essig 37. Symydobius chrysolepis Swain 177. Vacuna dryophila Schrank (f) Quince, see Cydonia Eadish, see Eaphanus Eagweed, see Ambrosia Ramona (black sage) 142. Aphis ramona Swain A SYNOPSIS OF THE APHIDIDAE 173 Ranunculus (buttercup) 132. Aphis middletonii Thomas 104. Rhopalosiphum persicae (Sulz.) 167. Thecabius californicus (Davidson) 168. Thecabius populiconduplifolius (Cowen) Raphanus (radish) 112. Aphis brassicae Linn. 141. Aphis pseudobrassicae Davis 104. Rhopalosiphum persicae (Sulz.) Eeed, Giant, see Arundo Eeed grass, see Phragmites Rhamnus (buckthorn, coffeeberry) 123. Aphis gossypii Glover 92. Myzus rhamnus (Clarke) Rhus (poison oak) 105. Rhopalosiphum rhois Monell Ribes (currant, gooseberry) 126. Aphis houghtonensis Troop 134. Aphis neo-mexicana Ckll. var. pacifica Dvdn. 89. Myzus cynosbati (Oestlund) 93. Myzus ribifolii Davidson Robinia (locust) 131. Aphis medicaginis Koch Rosa (rose, wild and cultivated) 67. Macrosiphum dirhodum (Walker) 76. Macrosiphum rosae (Linn.) 159. Myzaphis rosarum (Walker) 103. Myzus nervatum Gillette Eose, see Rosa Rose mallow, see Hibiscus Rubus (blackberry, loganberry, thimbleberry) 143. Aphis rubiphila Patch 57. Amphorophora rubi (Kalt.) 95. Nectarosiphon rubicola (Oestlund) Rumex (dock, sorrell) 121. Aphis euonomi Fabr. (rumicis Linn.) 123. Aphis gossypii Glover 146. Aphis senecio Swain 164. Pemphigus betae Doane (?) 104. Rhopalosiphum persicae (Sulz.) Eye, Wild, see Elymus Sagebrush, see Artemisia Sage, Black, see Ramona Salix (willow) 144. Aphis salicicola Thomas 146. Aphis senecio Swain 29. Arctaphis viminalis (Monell) 31. Fullaicaya saliciradicis Essig 64. Macrosiphum calif ornicum (Clarke) 30. Micrella monella Essig 182. Phylloxerina salicola (Pergande) 40. Pterocomma flocculosa (Weed) 174 MISCELLANEOUS STUDIES 41. Ptcrocomma populifoliae (Fitch) 42. Pterocomma smithiae (Monell) 155. Siphocoryne capreae (Fabr.) 38. Symydobius macrostachyae Essig 39. Symydobius salicicorticis Essig 32. Thomasia crucis Essig 34. Thomasia populicola (Thomas) 35. Thomasia salicola (Essig) 44. Tuberolachnus viminalis (Fonsc.) Sambucus (elderberry) 145. Aphis sambucifoliae Fitch 81. Macrosiphum stanleyi Wilson 104. Ehopalosiphum persicae (Sulz.) Sanicula (gambleweed) 119. Aphis cornifoliae Fitch 104. Ehopalosiplium persicae (Sulz.) Scrophularia (figwort) 99. Phorodon scrophulariae Thames Senecio (German ivy, ivy senecio) 144. Aphis senecio Swain 88. Myzus circumflexus (Buckton) 104. Ehopalosiphum persicae (Sulz.) Shepherd 's-purse, see Capsella Silybum (milk thistle) 121. Aphis euonomi Fabr. 130. Aphis marutae Oestlund Sisymbrium (hedge mustard) 88. Myzus circumflexus (Buckton) Smilax, see Asparagus Snowball, see Virburnum Snowberry, see Symphoricarpos Solatium (potato, nightshade) 56. Amphorophora laty siphon Davidson 79. Macrosiplium solanifolii (Ashmead) 88. Myzus circumflexus (Buckton) 102. Ehopalosiphum lactucae (Kalt.) 104. Ehopalosiphum persicae (Sulz.) 163. Trifldaphis radicicola (Essig) Sonchus (sow thistle) 79. Macrosiphum solanifolii (Ashmead) 80. Macrosiplium sonchella (Monell) 102. Ehopalosiphum lactucae (Kalt.) 104. Ehopalosiphum persicae (Sulz.) Sorghum 129. Aphis maidis Fitch Sorrell, see Eumex Sow thistle, see Sonchus Spinacia (spinach) 123. Aphis gossypii Glover 104. Ehopalosiphum persicae (Sulz.) Spirea (spirea) 148. Aphis spiraecola Patch A SYNOPSIS OF THE APH1DIDAE 175 Spruce, see Picea Squash, see Cucurbita Stachys (hedge nettle) 73. Macrosiphum ludovicianae (Oestlund) 88. Myzus circumflexus (Buckton) Stock, Ten-week, see Matthiola Strawberry, see Fragaria Strawberry tree, see Arbutus Sugar beet, see Beta Sunflower, see Helianthus Sweet clover, see Melilotus Sweet pea, see Latliyrus Sycamore, Western, see Platanus Symplwricarpos (snowberry) 108. Aphis albipes Oestlund Syringa (lilac) 131. Aphis medicaginis Koch Tacalote, see Centaurea Taraxacum (dandelion) 82. Macrosiplium taraxici (Kalt.) Tarweed, see Madia and Hemizonia Teasel, Fuller's, see Dipsacus Teasel, mustard, see Erysimum Thimbleberry, see Eubus Thistle, see Cirsium Thistle, Milk, see Silybum Thistle, Sow, see Sonchus Thuja (arbor vitae) 54. Lachnus tujafilinus (Del Guercio) Tilia (linden, basswood) 10. Eucallipterus tiliae (Linn.) Tomato, see Lycopersicum Tri folium (clover) 146a. Aphis bakeri Cowen 131. Aphis medicaginis Koch Trigonella (fenugreek) 69. Macrosiphum pisi (Kalt.) Triticum (wheat) 111. Aphis avenae Fabr. 64. Macrosiphum granarium (Kirby) Tropaeolum (nasturtium) 121. Aphis euonomi Fabr. 88. Myzus circumflexus (Buckton) 104. Ehopalosiphum pcrsicae (Sulz.) Tule, California, see Typha Tulip, see Tulipa Tulip tree, see Liriodendron Tulipa (tulip) 83. Macrosiphum tulipae (Monell) 104. Ehopalosiphum pcrsicae (Sulz.) Turnip, see Brassica 176 MISCELLANEOUS STUDIES Typha (California tule) 111. Aphis avenae Fabr. 153. Hyalopterus arundinis (Fabr.) 68. Macrosiphum granarium (Kirby) 156. Siphocoryne nymphaeae (Linn.) Ulmus (elm) 28. Arctaphis populifolii (Essig) (?) 172. .Colopha ulmicola (Fitch) 173. Eriosoma americana (Eiley) 175. Eriosoma languinosa Hartig (pyricola B. & D.) 174. Eriosoma lanigerum (Hausman) 79. Macrosiphum solanifolii (Ashmead) 22. Myzocallis ulmifolii (Monell) Umbellularia (California laurel) 88. Myzus circumflexus (Buckton) 104. Ehopalosiphum pcrsicae (Sulz.) 157. Siphocoryne pastinacae (Linn.) Urtica (stinging nettle) 121. Aphis euonomi Fabr. Valerian, Bed, see Centranthus Valeriana 84. Macrosiphum valerianae (Clarke) Vernonia (ironweed) 123. Aphis gossypii Glover Vetch, see Vicia Viburnum (lauristinus, snowball) 121. Aphis euonomi Fabr. 139. Aphis pomi De Geer 150. Aphis viburnicolens n.sp. Vicia (horse bean, vetch) 121. Aphis euonomi Fabr. (fabae Scop.) 131. Aphis medicaginis Koch 74. Macrosiphum pisi (Kalt.) Vigna (blackeye bean, cowpea) 131. Aphis medicaginis Koch Vineca (periwinkle) 56. Amphorophora latysiphon Davidson 88. Myzus circumflexus (Buckton) 104. Ehopalosiphum persicae (Sulz.) Viola (pansy, violet) 58. Idiopterus nephrelepidis Davis 74. Macrosiphum pisi (Kalt.) 88. Myzus circumflexus (Buckton) 106. Ehopalosiphum violae Pergande Vitis (grape) 180. Phylloxera vitifoliae (Fitch) Wallflower, ;,ee Cheiranthus Wallflower, Western, see Erysimum Walnut, see Juglans Water hemlock, see Cicuta Watermelon, see Citrullus Water plantain, see Alisma A SYNOPSIS OF THE APHIDIDAE 177 Wheat, see Triticum Willow, see Salix Yarrow, see Achillea Yucca (yucca) 151. Aphis yuccae Cowen Zantedeschia (calla) 88. Myzus circumflexus (Buckton) Zea (corn) 111. Aphis avenae Fabr. 128. Aphis maidis Fitch Zizia 155. Siphocoryne capreae (Fabr.) 178 MISCELLANEOUS STUDIES ADDENDA Since the preparation of this manuscript there have appeared a few papers36 in which there are some new records for certain of the California Aphididae and in which there are notes concerning the synonymy of some of the species. These records are noted here and are listed in the Host Plant Index (appendix 2). 2. Phyllaphis fagl (Linn.) on Fagus tricolor, Oakland (Essig, p. 321). 7. Euceraphis betulae (Koch) on Betula populifolia laciniata and B. papy- rifera (Essig, pp. 322-323). 10. Eucallipterus tiliae (Linn.) on Tilia tomentosa, Berkeley (Essig, p. 323). Baker places this species in the genus Myzocallis, for although it is quite distinct from the type of Myzocallis, various species form definite connections leading to this one. 15. Myzocallis castanicola Baker .(Baker, p. 424). This name has been sug- gested by Baker to replace M. castaneae (Buckton) (preoccupied by castaneae (Fitch)). Therefore the name suggested by the author, M. davidsoni Swain, must be dropped. Essig (p. 323) lists M. castaneae (Fitch), but he refers to this species. 19. Myzocallis californicus Baker (Baker, pp. 421-422). This is the same species as described by the author under the name, Myzocallis maureri Swain, which name will have to be dropped, and replaced by M. californicus Baker. 53a. Lachnus tomentosus (De Geer), on Finns radiata, Berkeley (Gillette, pp. 140-141). This species is very similar to L. pini-radiatae Davidson, accord- ing to Gillette. The author finds on looking over his specimens that some of them labeled L. pini-radiatae Dvdn. are this species, particularly those taken on the campus at Berkeley. 56. Amphorophora latysiphon Davidson, on Chrysanthemum and Primula sp., Berkeley (Essig, p. 329). 68. Macrosiphum granarium (Kirby), on Alopecurus pratensis, Ampelodesma tenax, and Elymus sp., Martinez (Essig, p. 328). 76. Macrosiphum rosae (Linn.) on Dipsacus fullonum and Centranthus ruber, Berkeley (Essig, p. 329). 79. Macrosiphum solanifolii (Ashmead), on Achillea millefolium and Pitto- sporum tobira, Berkeley, and on TJlmus americanus, San Francisco (Essig, p. 329). 88. Myzus circumflexus (Buckton), on Lilium spp., Pentstemon spcctabilis, and Umbellularia calif ornica, Berkeley (Essig, p. 335). 102. Rhopalosiphum lactucae (Kalt.). Dobrovliansky lists this as a synonym of E. ribis (Buckton), giving the latter name preference. so Baker, A. C., Eastern aphids, new and little known, II, Jour. Econ. Ent., vol. 10, pp. 421-433, 1917. Baker, A. C.. The correct name for our apple-grain aphis, Science, vol. 46, pp. 410-411, 1917. Davidson, W. M., The reddish-brown plum aphis, Jour. Econ. Ent., vol. 10, pp. 350-353, 1917. Dobrovliansky, V. V., A list of aphids found on cultivated plants in the gov- ernment of Kharkov, in Pests of Agriculture, Kharkov, Bull. 1916; reviewed in Kev. Appl. Ent., vol. 5, pp. 561-562, 1917. Essig, E. O., Aphididae of California, Univ. Calif. Publ. Entom., vol. 1, pp. 301-346, 1917. Gillette, C. P., Some Colorado species of the genus Lachnus, Ent. Soc. Am., vol. 10, pp. 133-146, 1917. Van der Goot, P., Zur Kenntnis der Blattlause Java's, in Contrib. a la fauna der Indes neerlandaises, vol. 1, pp. 1-301, 1916. A SYNOPSIS OF THE APHIDIDAE 179 104. Rhopalosiphum persicae (Sulzer), on Baccharis douglasii, Centranthus ruber, Clarkia elegans, Dipsacus fullonum, Escallonia pulverulenta, Helianthus annuus, Lavatera assurgentiflora, Liriodendron tulipifera, Melianthus major, Pentstemon spectabilis, PittosporUm spp., and Umbellularia californica, Berkeley (Essig, pp. 331-332). 111. Aphis avenae Fabr. It would appear from a study of Baker's paper in Science that the common California species is Aphis prunifoliae Fitch. It is certain that it is distinct from A. cerasifoliae Fitch, which has been taken here once and is described in this paper. If it is possible, as Baker says, that A. cerasifoliae Fitch is a synonym of A. padi Linn., then our common species must be known as A. prunifoliae Fitch. From the brief description of Aphis (Siphon- aphis) padi Linn, given by Van der Goot (pp. 71-72) it would appear that our species may be distinct, differing slightly in the comparative lengths of the cornicles and cauda. Consequently the author favors accepting the name, Aphis prunifoliae Fitch, for this species. 123. Aphis gossypii Glover, on Asclepias speciosa, A. vestita, Lilium speciosum rubrum, Lonicera sp., and Ehamnus purshiana, Berkeley and Oakland (Essig, pp. 338-339). 131. Aphis raedicaginis Koch, on Citrus sp., Sacramento, and on Vigna sin- ensis, Moorpark (Essig, p. 340). 139. Aphis pomi De Geer, on Cotoneaster franchetii, Pittosporum eugenioides, and Viburnum tinus, Berkeley (Essig, p. 341). The author is inclined to believe this to be Aphis viburnicolens n.sp. (see no. 150) which is quite similar to Aphis pomi De Geer, but which is common on Viburnum and related plants. He has not, however, seen Essig 's specimens, so can not state positively whether or not it is this species. 140. Aphis prunorum Dobr. Dobrovliansky places this species as a synonym of Siphocoryne nymphaeae (Linn.). This author noted the similarity of these two, but was not certain of their identity, so listed them as distinct species. 141. Aphis pseudobrassicae Davis. Dobrovliansky believes this to be a syno- nym of Aphis erysimi Kalt. 146. Aphis senecio Swain. Essig (p. 337) lists Aphis bakeri Cowen from Trifolium pratense. This proves to be the true Aphis bakeri Cowen and not A. senecio Swain, which is the species that has been hitherto called A. balceri Cowen in California. 152. Toxoptera aurantii (Fonsc.) on Camellia japonica, Oakland (Essig, p. 330). 153. Hyalopterus arundinis (Fabr.). Both Dobrovliansky and Van der Goot list this as a synonym of H. pruni (Fabr.) giving the later preference. Accord- ing to Hunter, arundinis should have priority, but it is entirely possible that the dates he gives are incorrect. This point the author is unable to settle as he has not access to Fabricius' works. 156. Siphocoryne nymphaeae (Linn.). Davidson gives a brief account of the habits and biology of this species, as well as a description of the various forms. 175. Eriosoma languinosa Hartig (pyricola Baker and Davidson). The species listed by Essig (p. 345) as Eriosoma sp. on Ulmus campestris in Berkeley and in Hayward is this species. 115. Aphis carl Essig. Davidson recently remarked to the author that he could see no difference between this species and Aphis helianthii Monell. It is quite possible that these are synonyms. EXPLANATION OF PLATES PLATE 1 Fig. 1. Myzocallis asclepiadis (Fitch), tarsus and claw. Fig. 2. Aphis senecio Swain, tarsus and claw. Fig. 3. Essigella calif ornica (Essig), sixth antennal segment and spur. Fig. 4. Aphis senecio Swain, sixth antennal segment and spur. Fig. 5. Essigella californica (Essig), cauda and anal plate (lateral view). Fig. 6. Aphis senecio Swain, cauda and anal plate (lateral view). Fig. 7. Eucallipterus tiliae (Linn.), cauda and anal plate. Fig. 8. Thomasia populicola (Thos.), cauda and anal plate. Fig. 9. Phyllaphis fagi (Linn.), third antennal segment. Fig. 10. Phyllaphis fagi (Linn.), sixth antennal segment. Fig. 11. Phyllaphis fagi (Linn.), cauad and anal plate. Fig. 12. Phyllaphis fagi (Linn.), front of head and antennal tubercles. Fig. 13. Phyllaphis coweni (Ckll.), Antenna. Fig. 14. Phyllaphis quercicola Baker, third antennal segment. Fig. 15. Phyllaphis quercicola Baker, fourth antennal segment. Fig. 16. Phyllaphis quercicola Baker, fifth antennal segment. Fig. 17. Phyllaphis quercicola Baker, sixth antennal segment. Fig. 18. Phyllaphis quercicola Baker, forewing. Fig. 19. Phyllaphis quercicola Baker, cauda and anal plate. Fig. 20. Phyllaphis querci, tarsal claw. Fig. 21. Drepanosiphum platanoides (Schr.), antennal tubercles. [180] [SWAIN ] PLATE 1 PLATE 2 Fig. 22. Myzocallis arundicolens (Clarke), antennal tubercles. Fig. 23. Drepanaplils acerifolii (Thomas), cornicle. Fig. 24. Drepano»iphum platanoides (Schr.), cornicle. Fig. 25. Monellia caryella (Fitch), cornicle. Fig. 26. Myzocallis bcllus (Walsh), cornicle. Fig. 27. Calaphis betulaecolens (Fitch), antennal tubercles. Fig. 28. Calaphis betulella Walsh, antennal tubercles. Fig. 29. Euceraphis betulae (Koch), antennal tubercles. Fig. 30. Eucallipterus tiliae (Linn.), sixth antennal segment and spur. Fig. 31. Myzocallis quercus (Kalt.), sixth antennal segment and spur. Fig. 32. Myzocallis quercus (Kalt.), cornicle. Fig. 33. Eucallipterus tiliae (Linn.), cornicle. Fig. 34. Chromaphis juglandicola (Kalt.), sixth antennal segment and spur. Fig. 35. Chromaphis juglandicola (Kalt.), cornicle. Fig. 36. Drepanosiphum platanoides (Schr.), third antennal segment. Fig. 37. Drepanaphis acerifolii (Thomas), third antennal segment. Fig. 38. Calaphis betulae-colens (Fitch), third antennal segment. Fig. 39. Euceraphis gillettei Dvdn., base of third antennal segment. Fig. 40. Euceraphis betulae (Koch), base of third antennal segment. [ SWAIN ] PLATE 2 PLATE 3 Fig. 41. Eucalli'pterus flava (Dvdn.), base of third antennal segment. Fig. 42. Eucallipterus tiliae (Linn.), third antennal segment. Fig. 43. Myzocallis coryli (Goetze), third antennal segment. Fig. 44. Myzocallis coryli (Goetze), sixth antennal segment and spur. Fig. 45. Myzocallis bellm (Walsh), sixth antennal segment and spur. Fig. 46. Myzocallis bellus (Walsh), third antennal segment. Fig. 47. Myzocallis alnifoliae (Fitch), third antennal segment. Fig. 48. Myzocallis arundicolens (Clarke), third antennal segment. , Fig. 49. Eucallipterus tiliae (Linn.), cornicle. Fig. 50. Eucallipterus tiliae (Linn.), anal plate. Fig. 51. Myzocallis arundicolens (Clarke), cornicle. Fig. 52. Myzocallis arundicolens (Clarke), anal plate. Fig. 53. Myzocallis coryli (Goetze), cornicle. Fig. 54. Myzocallis coryli (Goetze), anal plate. Fig. 55. Myzocallis californicus Baker, third antennal segment. Fig. 56. Myzocallis californicus Baker, sixth antennal segment and spur. Fig. 57. Myzocallis pasaniae Dvdn., third antennal segment. Fig. 58. Myzocallis quercus (Kalt.), third antennal segment. Fig. 59. Myzocallis ulmifolii (Monell), third antennal segment. Fig. 60. Myzocallis castanicola Baker, third antennal segment. Fig. 61. Myzocallis castanicola Baker, cauda and anal plate. Fig. 62. Myzocallis castanicola Baker, cornicle. Fig. 63. Callipterus californicus (Essig), sixth antennal segment and spur. Fig. 64. Callipterus californicus (Essig), third antennal segment. Fig. 65. Callipterus caryae Monell, third antennal segment. [184] 5a3 TS 49 50 55 56 57 5\ 54 [ SWAIN ] PLATE 3 PLATE 4 Fig. 66. Callipterus caryae Monell, sixth antennal segment and spur. Fig. 67. Monellia caryella (Fitch), sixth antennal segment and spur. Fig. 68. Monellia caryella (Fitch), third antennal segment. Fig. 69. Arctaphis populifolii (Essig), cauda. Fig. 70. Micrella monella Essig, cauda. Fig. 71. Arctaphis populifolii (Essig), third antennal segment. Fig. 72. Micrella monella Essig, third antennal segment. Fig. 73. Symydobius macrostachyae Essig, third antennal segment. Fig. 74. Symydobius salicicorticis Essig, third antennal segment. Fig. 75. Fullawaya saliciradicis Essig, third antennal segment. Fig. 76. Thomasia, crucis Essig, third antennal segment. Fig. 77. Thomasia populicola (Thomas), third antennal segment. Fig. 78. Thomasia salicicola (Essig), third antennal segment. Fig. 79. Lachnus ferrisi Swain, tarsal claw. Fig. 80. Pterocomma populifoliae (Fitch), tarsal claw. Fig. 81. Pterocomma flocculosa (Weed), cornicle. Fig. 82. Pterocomma populifoliae (Fitch), cornicle. Fig. 83. Essigella calif ornica (Essig), antenna. Fig. 84. Longistigma sp., front wing. [186] OQ06 71 70 74 [ SWAIN ] PLATE 4 PLATE 5 Fig. 85. Lachnus sp., front wing. Fig. 86. Tuberolachnus viminalis (Fonsc.), hind tarsus. Fig. 87. Eulachnus rileyi Davis, hind tarsus. Fig. 88. Lachnus vanduzei n.sp., third antennal segment. Fig. 89. Lachnus ferrisi Swain, first, second, and third antennal segments. Fig. 90. Laohnus ferrisi Swain, fourth, fifth, and sixth antennal segments. Fig. 91. Lachnus ferrisi Swain, cornicle. Fig. 92. Lachnus pseudotsugae Wilson, tip of front wing. Fig. 93. Lachnus tujafilinus (Del Guercio), tip of front wing. Fig. 94. Lachnus occidentalis Dvdn., third antennal segment. Fig. 95. Lachnus pini-radiatae Dvdn. (?), third antennal segment. Fig. 96. Lachnus glehnus Essig, third antennal segment. Fig. 97. Lachnus glehnus Essig, cornicle. Fig. 98. Lachnus pseudotsugae Wilson, third antennal segment. Fig. 99. Lachnus taxifolia Swain, hind tarsus. Fig. 100. Lachnus taxifolia Swain, fourth, fifth and sixth antennal segments. Fig. 101. Lachnus taxifolia Swain, first, second, and third antennal segments. [188] [ SWAIN 1 PLATE 5 PLATE 6 Fig. 102. Laolmus taxifolia Swain, wing. Fig. 103. Lachnus taxifolia Swain, cornicle of apterous female. Fig. 104. Lachnus ponderosa Williams, third antennal segment. Fig. 105. Lachnus tujafilinus (Del Guercio), third antennal segment. Fig. 106. Macrosiphum rosae (Linn.), antennal tubercles. Fig. 107. Nectaro-siphon rubicola (Oest.), antennal tubercles. Fig. 108. Ehopalosiphum persicae (Sulz.), antennal tubercles. Fig. 109. Nectarosiphon rubicola (Oest.), cornicle. Fig. 110. Idiopterus nephrelepidis Davis, wing. Fig. 111. Amphorophora rubi (Kalt.), antennal tubercles. Fig. 112. Myzus cerasi (Fabr.), antennal tubercles. Fig. 113. Amplioropliora rubi (Kalt.), cornicle. Fig. 114. Toxoptera aurantii (Fonsc.), cornicle. Fig. 115. Phorodon Jiumuli (Schr.), antennal tubercles of alate females. Fig. 116. Phorodon Jiumuli (Schr.), antennal tubercles of apterous females. UH>| 113 [SWAIN] PLATE 6 PLATE 7 Fig. 117. Phorodon humuli Schr., cornicle. Fig. 118. Phorodon humuli Schr., cauda. Fig. 119. Ehopalosiphum persicae (Sulz.), cornicle. Fig. 120. Ehopalosiphum pcsicae (Sulz.), cauda. Fig. 121. Myzus cerasi (Fabr.), cornicle. Fig. 122. Myzus cerasi (Fabr.), cauda. Fig. 123. Nectarosiphon rubicola (Oest.), cauda. Fig. 124. Nectarosiphon morrisoni Swain, antennal tubercles. Fig. 125. Nectarosiphon morrisoni Swain, third antennal segment. Fig. 126. Nectarosiphon morrisoni Swain, cauda. Fig. 127. Nectarosiphon morrisoni Swain, cornicle. Fig. 128. Macrosiphum stanleyi Wilson, cornicle. Fig. 129. Macrosiphum solanifolii (Ashm.) (from Sonchus), cornicle. Fig. 130. Macrosiphum pisi (Kalt.), cornicle. Fig. 131. Macrosiphum californicum (Clarke), third antennal segment. Fig. 132. Macrosiphum californicum (Clarke), cornicle. Fig. 133. Macrosiphum cucurbitae (Thomas), third antennal segment. Fig. 134. Macrosiphum cucurbitae (Thomas), cornicle. Fig. 135. Macrosiphum granarium (Kirby), third antennal segment. Fig. 136. Macrosiphum ludovicianae (Oest.), third antennal segment. Fig. 137. Macrosiphum solanifolii (Ashm.), cornicle. Fig. 138. Macrosiphum solanifolii (Ashm.), third antennal segment. [192] SoS? 0°°o ^ °o °0 Qo°o° 'o O O go°o g 00000o0o° I3JT o o o ° o o OQ OQ_00__; 3 go ° [ SWAIN ] PLATE 7 PLATE 8 Fig. 139. Macrosiphum solanifolii (Ashm.) (from Citrus), cornicle. Fig. 140. Macrosiphum solanifolii (Ashm.) (from Citrus), third antennal segment. Fig. 141. Macrosiphum sanborni Gillette, cornicle of apterous female. Fig. 142. Macrosiphum artemisiae (Fonsc.), cornicle. Fig. 143. Macrosiphum albifrons Essig, third antennal segment. Fig. 144. Macrosiphum albifrons Essig, cornicle. Fig. 145. Macrosiphum artemisiae (Fonsc.), third antennal segment. Fig. 146. Macrosiphum artemisicola (Williams), third antenal segment. Fig. 147. Macrosiphum artemisicola (Williams), cornicle. Fig. 148. Macrosiphum granarium (Kirby), cornicle. Fig. 149. Macrosiphum ludovicianae (Oest.), cornicle. Fig. 150. Macrosiphum pisi (Kalt.), third antennal segment. Fig. 151. Macrosiphum rosae (Linn.), third antennal segment. Fig. 152. Macrosiphum rosae (Linn.), cornicle. Fig. 153. Macrosiphum rudbeclciae (Fitch), cornicle. Fig. 154. Macrosiphum rudbeclciae (Fitch), third antennal segment. Fig. 155. Macrosiphum sanborni Gillette, cauda apterous female. Fig. 156. Macrosiphum dirhodum (Walker), cornicle. Fig. 157. Macrosiphum dirhodum (Walker), third antennal segment. Fig. 158. Macrosiphum stanleyi Wilson, third antennal segment. Fig. 159. Macrosiphum solanifolii (Ashm.) (from Souchus), third antennal segment. Fig. 160. Macrosiphum solanifolii (Ashm.) (from Sonchus), cauda. 194] 160 [SWAIN ] PLATE 8 Fig. 161. Fig. 162. Fig. 163. Fig. 164. Fig. 165. Fig. 166. Fig. 167. Fig. 168. Fig. 169. segment. Fig. 170. Fig. 171. ment. Fig. 172. Fig. 173. Fig. 174. Fig. 175. Fig. 176. Fig. 177. Fig. 178. Fig. 179. Fig. 180. Fig. 181. Fig. 182. Fig. 183. Fig. 184. Fig. 185. ments. Fig. 186. PLATE 9 Amphorophora latysiphon Dvdn., cornicle. Amphorophora rubi (Kalt.), cauda. Toxoptera aurantii (Fonsc.), third antennal segment. Ehopalosiphum violae Pergande, wing. Ehopalosiphum hippophaes Koch, cornicle. Ehopalosiphum nervatum Gillette (from Arbutus), wing. Ehopalosiphum corylinum Dvdn., third antenpal segment. Ehopalosiphum persicae (Sulz.), third antennal segment. Ehopalosiphum nervatum Gillette (from Arbutus), third antennal Bhopalosiphum hippophaes Koch, third antennal segment. Ehopalosiphum nervatum Gillette (from rose), third antennal seg- Siphocoryne nymphaeae (Linn.), third antennal segment. Ehopalosiphum rhois Monell, third antennal segment. Ehopalosiphum violae Pergande, third antennal segment. Myzus circumflexus (Buckton), third antennal segment. Myzus braggii Gillette, third antennal segment. Myzus fragaefolii Ckll., third antennal segment. Myzus rhamni (Fonsc.), third antennal segment. Myzus cerasi (Fabr.), third antennal segment. Myzus ribis (Linn.), third antennal segment. Hyalopterus arundinis (Fabr.), cornicle. Aphis euonomi Fabr., cornicle. Siphocoryne capreae (Fabr.), cornicle. Liosomaphis berberidis (Kalt.), conricle. Hyalopterus arundinis (Fabr.), third and fourth antennal seg- Hyalopterus arundinis (Fabr.), cauda. [196] IS2 if 5 ( SWAIN ] PLATE 9 PLATE 10 Fig. 187. Aphis euonomi Fabr., wing. Fig. 188. Aphis salicicola Thomas, wing. Fig. 189. Aphis medicaginis Koch, third and fourth antennal segments. Fig. 190. Aphis euonomi Fabr. (I), third and fourth antennal segments. Fig. 191. Aphis avenae Fabr., wing. Fig. 192. Aphis gossypii Glover, cornicle. Fig. 193. Aphis gossypii Glover, cauda. Fig. 194. Aphis sambucifoliae Fitch, cauda. Fig. 195. Aphis sambucifoliae Fitch, cornicle. Fig. 196. Myzaphis abietina (Walker), third and fourth antennal segments. Fig. 197. Myzaphis abietina (Walker), cornicle. Fig. 198. Aphis albipes Oest., cornicle. Fig. 199. Aphis albipes Oest., cauda. Fig. 200. Aphis albipes Oest., third and fourth antennal segments. Fig. 201. Aphis avenae Fabr., cornicle. Fig. 202. Aphis avenae Fabr., third and fourth antennal segments. Fig. 203. Aphis brassicae Linn., cornicle. Fig. 204. Aphis brassicae Linn., third and fourth antennal segments. Fig. 205. Aphis euonomi Fabr., cornicle. Fig. 206. Aphis euonomi Fabr., cornicle. Fig. 207. Aphis euonomi Fabr., third and fourth antennal segments. Fig. 208. Aphis cardui Linn., third and fourth antennal segments. Fig. 209. Aphis cardui Linn., cornicle. Fig. 210. Aphis ceanothi Clarke, cornicle. Fig. 211. Aphis ceanothi Clarke, third and fourth antennal segments. Fig. 212. Aphis coolcii Essig, third and fourth antennal segments. Fig. 213. Aphis coolcii Essig, cauda and anal plate. Fig. 214. Aphis coolcii Essig, cornicle. Fig. 215. Aphis gossypii Glover, third and fourth antennal segments. Fig. 216. Aphis maidis Fitch, cauda. Fig. 217. Aphis maidis Fitch, antenna. Fig. 218. Aphis maidis Fitch, cornicle. Fig. 219. Aphis middletonii Thomas, cornicle. Fig. 220. Aphis middletonii Thomas, third and fourth antennal segments. Fig. 221. Aphis nerii Fonsc., cornicle. Fig. 222. Aphis nerii Fonsc., third and fourth antennal segments. Fig. 223. Aphis persicae-niger Smith, cornicle. Fig. 224. Aphis persicae-niger Smith, third and fourth antennal segments. [198] I SWAIN ] PLATE 10 PLATE 11 Aphis pomi De Geer, canda. Aphis pomi De Geer, antennae. Aphis pomi De Geer, cornicle. Aphis prunorum Dobr., cauda. Aphis prunorum Dobr., third and fourth antennal segments. Aphis prunorum Dobr., cornicle. Aphis pscudobrassicac Davis, third and fourth antennal segments. Aphis ramona Swain, antenna. Aphis ramona Swain, front of head. Aphis ramona Swain, cauda and anal plate. Aphis ramona Swain, cornicle. Aphis euonomi Fabr., cornicle. Aphis euonomi Fabr., third and fourth antennal segments. Aphis salicicola Thomas, cornicle. Aphis salicicola Thomas, third and fourth antennal segments. Aphis sambucifoliae Fitch, third and fourth antennal segments. Aphis senecio Swain, cauda. Aphis senecio Swain, cornicle. Aphis senecio Swain, front of head. Aphi-s senecio Swain, third and fourth antennal segments. Aphis senecio Swain, fifth, sixth antennal segments, and spur. Aphis setarae Thomas, cornicle. Aphis setarae Thomas, third and fourth antennal segments. Aphis malifoliae Fitch, cornicle. Aphis malifoliae Fitch, fourth antennal segment. Liosomaphis berberidis (Kalt.), front of head. Liosomaphis berberidis (Kalt.), third and fourth antennal seg- Siphocoryne capreae (Fabr.), third and fourth antennal segments. Siphocoryne capreae (Fabr.), fifth and sixth antennal segments Siphocoryne capreae (Fabr.), cauda and supra-caudal spine of alate Fig. 225. Fig. 226. Fig. 227. Fig. 228. Fig. 229. Fig. 230. Fig. 231. Fig. ( 232. Fig. '233. Fig. 234. Fig. 235. Fig. 236. Fig. 237. Fig. 238. Fig. 239. Fig. 240. Fig. 241. Fig. 242. Fig. 243. Fig. 244. Fig. 245. Fig. 246. Fig. 247. Fig. 248. Fig. 250. Fig. 251. Fig. 252. ments. Fig. 253. Fig. 254. and spur. Fig. 255. females. Fig. 256. Siphocoryne capreae (Fabr.), cauda and supra-caudal spine of apterous females. Fig. 257. Siphocoryne pastinacae (Linn.), third and fourth antennal seg- ments. Fig. 258. Siphocoryne pastinacae (Linn.), fifth and sixth antennal segments and spur. Fig. 259. Siphocoryne pastinacae (Linn.), cauda of apterous female. Fig. 260. Siphocoryne pastinacae (Linn.), cauda of alate female. Fig. 261. Siphocoryne pastinacae (Linn.), cornicle. [200] 241 [ SWAIN ] PLATE 1 1 PLATE 12 Fig. 262. Mysocallis discolor (Monell), fore wing. Fig. 263. Myzocallis discolor (Monell), third antennal segment. Fig. 264. Mysocallis bellus (Walsh), fore wing. Fig. 265. Myzocallis bellus (Walsh), third antennal segment. Fig. 266. Myzocallis calif ornicus Baker (maureri Swain), fore wing. Fig. 267. Myzooallis castanicola Baker ^davidsoni Swain), fore wing. Fig. 268. Myzocallis arundinariae Essig, third antennal segment. [202] 2 66 ztr [ SWAIN ] PLATE 12 ~(j U v UV U — •— •f' PLATE 13 Fig. 269. Symydobius chrysolepis Swain, head. Fig. 270. Symydobius chrysolepis Swain, cornicle. Fig. 271. Symydobius chrysolepis Swain, anal plate. Fig. 272. Symydobius chrysolepis Swain, antenna. Fig. 273. Symydobius chrysolepis Swain, fore wing. Fig. 274. Symydobius chrysolepis Swain, hind wing. Fig. 275. Thomasia populicola (Thomas), fore wing. [204] Z72 274 275 [ SWAIN ] PLATE 13 PLATE 14 Fig. 276. Toxoptera aurantii (Fonsc.), fore wing. Fig. 277. Rhopalosiphum lactucae (Kalt) head. Fig. 278. Rhopalosiphum lactucae (Kalt.), third antennal segment, aptera. Fig. 279. Rhopalosiphum lactucae (Kalt.), third antennal segment, alate. Fig. 280. Rhopalosiphum lactucae (Kalt.), fourth and fifth antennal seg- ments, alate. Fig. 281. Rhopalosiphum lactucae (Kalt.), sixth antennal segment, alate. Fig. 282. Rhopalosiphum lactucae (Kalt.), cornicle, alate. Fig. 283. Rhopalosiphum lactucae (Kalt.), cauda, alate. Fig. 284. Rhopalosiphum lactucae (Kalt.), cornicle, aptera. Fig. 284a. Rhopalosiphum lactucae (Kalt.), cauda, aptera. [206] 2 7k 277 Z&Z 2Z4 279 2 SO [SWAIN] PLATE 14 PLATE 15 Fig. 285. Aphis viburnicolens n.sp., third antennal segment. Fig. 286. Aphis viburnicolens n.sp., cornicle. Fig. 287. Aphis viburnicolens n.sp., cauda. Fig. 288. Aphis cerasifoliae (Fitch), head. Fig. 289. Aphis cerasifoliae (Fitch), fifth and sixth antennal segments. Fig. 290. Aphis cerasifoliae (Fitch), third and fourth antennal segments. Fig. 291. Aphis cerasifoliae (Fitch), end of wing. Fig. 292. Aphis cerasifoliae (Fitch), side of abdomen showing cauda, cor- nicle, and lateral tubercles on segments one, two, three, four, and seven. [208] 2S5 [ SWAIN ] PLATE 15 Tig. 293. Aphis Fig. 294. Aphis Fig. 295. Aphis Fig. 296. Aphis Fig. 297. Aphis Fig. 298. Aphis Fig. 299. Aphis Fig. 300. Aphis antennal segments. Fig. 301. Aphis Fig. 302. Aphis Fig. 303. Aphis Fig. 304. Aphis Fig. 305. Aphis PLATE 16 marutae Oest., head. marutae Oest., third and fourth antennal segments. marutae Oest., fifth and sixth antennal segments. marutae Oest., antenna, aptera. marutae Oest., end of abdomen, aptera. marutae Oest., cauda, alate. marutae Oest., cornicle, alate. neomexicana Ckll., var. paoifica Dvdn., third and fourth neomexicana Ckll. var. pacifica Dvdn., cornicle. neomexicana Ckll. var. pacifica Dvdn., cauda. yuccae Cowen, fourth, fifth, and sixth antennal segments. yuccae Cowen, third antennal segment. yuccae Cowen, tip of abdomen. 293 294 295 296 29S- 299 do; 30* 504 SWAIN ] PLATE; 16 PLATE 17 Fig. 306. Myzus ribis (Linn.), head. Fig. 307. Myzus cerasi (Fabr.), head. Fig. 308. Myzaphis rosarum (Walker), head, alate. Fig. 309. Myzaphis rosarum (Walker), third and fourth antennal segments. Fig. 310. Myzaphis rosarum (Walker), fifth and sixth antennal segments. Fig. 311. Mysaphis rosarum (Walker), tip of wing. Fig. 312. Myzaphus rosarum (Walker), end of abdomen. Fig. 313. Myzaphis rosarum (Walker), head, aptera. Fig. 314. Myzaphis rosarum (Walker), antenna, aptera. Fig. 315. Myzaphis rosarum (Walker), cornicle, aptera. Fig. 316. Myzaphis rosarum (Walker), cauda, aptera. Fig. 317. Myzaphis rosarum (Walker), hind tarsus, aptera. [212] 507 303" 31 3 315 [ SWAIN 1 PLATE 17 A SYNOPSIS OF THE APHIDIDAE 215 INDEX TO GENEEA AND SPECIES abietes, Lachnus, 47. abietina, Myzaphis (Aphis), 134. abietinus, Mindarus, 150. acerifolii, Drepanaphis (Siphono- phora, Macrosiphum), 18. achyrantes, Rhopalosiphum, 80. agrifoliae, Symydobius, 38. alamedensis, Aphis, 93. albifrons, Macrosiphum, 60. albipes, Aphis, 93. alni, Myzocallis, 21. alnifoliae, Callipterus, 20. alnifoliae Lachnus, 20. alnifoliae Myzocallis, 22. alnifoliae Prociphilus (Pemphigus}, 146. ambrosiae, Macrosiphum (Siphono- phora), 60. americana, Eriosoma (Schizoneura), 148. Amphorophora, 54. cicutae, 54. latysiphon, 54, 178. rubi, 54. rubicola, 77. angelicae, Aphis, 93. annulata, -Callipterinella (Chaitopho- rus), 31. Aphis, 88. abietina, 134. alamedensis, 93. albipes, 93. angelicae, 93. artemisiae, 61. arundinis, 130. atriplicis, 93. aurantii, 129. avenae, 94, 179. bakeri, 123, 124. bakeri, 6, 179. h< 'I in*. 24. berberidis, 130. betulaecolens, 18. brassicae, 95. calendulicola, 96. capreae, 132. cardui, 96. cari, 96, 179. caryella, 30. ceanothi, 96. ceanothi-hirsuti, 96. cerasi, 73. cerasifoliae, 97. citri, 105. eooki, 100. cornifoliae, 100. coryli, 25. crataegifoliae, 100. dirhodum, 63. dryophila, 150. euonomi, 101. fabae, 102, 104. fagi, 13. frigidae, 105. gossypii, 100. gossypii, 105, 179. granarium, 64. hederae, 106. heraclei, 107. houghtonensis, 107. humuli, 79. juglandis, 28. lactucae, 82. languinosa, 149. lanigerum, 149. lithospermi, 108. lutescens, 117. maidis, 94. maidis, 108. mali, 120. malifoliae, 108. marutae, 112. medicaginis, 114, 179. middletonii, 115. mori, 116. neomexicana, 116. nerii, 117. nymphaeae, 133. oenotherae, 118. oregonensis, 119. padi, 94. papaveris, 102, 104. pastinacae, 133. persicae, 85. persicae-niger, 119. pisi, 66. platanoides, 17. pomi, 120, 179. pomi, 109. populifoliae, 41. pruni, 96. prunorum, 121, 179. prunifoliae, 130, 179. pseudobrassicae, 122, 179. quercus, 27. ramona, 122. rhamni, 76. rosae, 67. rosarum, 134. rubi, 54. rubiphila, 122. rudbeckiae, 67. rufomaculata, 137. rumtcis, 101, 106. salicicola, 123. sambucifoliae, 123. senecio, 123, 179. setariae, 124. 216 MISCELLANEOUS STUDIES sorbi, 108. spiraecola, 1-1. spiraeella, 125, 126. taraxici, 71. tetrapteralis, 125. tiliae, 21. viburnicolens, 126, 179. viminalis, 45. yuccae, 45. yuccicola, 128. aquilegiae, Myzus, 73. arbuti, Ehopalosiphum, 84. Aretaphis, 33. populifolii, 33. viminalis, 34. artemisicola, Macrosiphum (Siphono- phora), 61. artemisiae, Macrosiphum (Aphis), 61. arundicolens, Eucallipterus (Myzocal- lis}, 24. arundicolens, Myzocallis (Callipterus) , 22. arundinariae, Myzocallis, 24. arundinis, Hyalopterus (Aphis'), 130, 179. atriplicis, Aphis, 93. aurantiae, Toxoptera, 129. aurantii, Toxoptera (Aphis), 129, 179. avenae, Aphis (Nectarophora, Sipho- coryne), 94, 179. B baccharadis, Macrosiphum (Nectaro- phora), 61. bakeri, Aphis, 123. bakeri, Aphis, 6, 179. balsamiferae, Pemphigus, 142. bellus, Myzocallis (Aphis, Callip- terus), 24. berberidis, Liosomaphis (Aphis, Bho- palosiphum) , 130. betae, Pemphigus, 142. betulae, Chaitophorus, 31. betulae, Euceraphis (Callipterus) , 19, 178. betulaecolens, Calaphis (Aphis, Cal- lipterus), 18. braggii, Myzus, 73. brassicae, Aphis, 95. Byrsocrypta, 148. ulmicola, 148. calendulieola, Aphis, 96. Calaphis, 18. betulaecolens, 18. castaneae, 24. calif ornica, Essigella (Lachnus), 44. calif ornicum, Macrosiphum (Nectaro- phora), 62. calif ornicus, Callipterus (Monellia), 29. californicus Myzocallis, 178. calif ornicus Thecabius (Pemphigus), 144. Callipterinella, 31. annulata, 31. Callipterus, 28. alnifoliae, 20. arundicolens, 22. bellus, 24. betulae, 19. betulaecolens, 18. californicus, 29. caryae, 29. caryella, 30. castaneae, 24. coryli, 25. discolor, 25. hyalinus, 26. juglandicola, 28. juglandis, 28. punctatus, 26. quercus, 27. tiliae, 21. ulmifolti, 27. viminalis, 34. capreae, Siphocoryne (Aphis), 132. cardui, Aphis, 96. carduinum, Phorodon, 73. cari, Aphis, 96, 179. caryae, Callipterus (ifone^ia), 29. caryella, Monellia ( Aphis, Callip- terus), 30. castaneae, Calaphis (Callipterus), 24. castaneae, Myzocallis, 178. castanicola, Myzocallis, 178. ceanothi, Aphis, 96. ceanothi-hirsuti, Aphis, 96. cerasi, Myzus (Aphis), 73. cerasifoliae, Aphis, 97. Cerataphis, 140. lataniae, 140. Cerosipha, 137. cupressi, 137. Chaitophorus, 33. annulata, 31. betulae, 31. negundinis, 36. nigrae, 37. populieola, 36. populifoliae, 33. salicieola, 37. smithiae, 34. vtmt'jiaZis, 34. Chermes, 151. cooleyi, 151. coweni, 151. pinicorticis, 152. Chromaphis, 28. juglandicola, 28. chrysanthemi, Macrosiphum (Siphono- phora), 62. chrysanthemi, Macrosiphum, 69. chrysolepis, Symydobius, 38. cicutae, Amphorophora, 54. circumflexus, Myzus (Siphonophora). citri, Aphis, 105. A SYNOPSIS OF THE APHIDIDAE 217 citrifolii, Macrosiphum (Nectaro- phora), 69. Cladobius, 41. rufulus, 41. salicti, 43. Coccus, 140. lataniac, 140. pinicorticis, 152. Colopha, 148. ulmicola, 148. Coloradoa, 137. rufomaculata, 137. conii, Siphocoryne, 133. cooki, Aphis, 100. cooleyi, Chermes, 151. cornifoliae, Aphis, 100. coryli, Myzocallis (Aphis, Callip- terus), 25. corylinum, Rhopalosiphum, 81. coweni, Chermes, 151. coweni, Phyllaphis (Pemphigus), 13. crataegifolii, Aphis, 100. crueis, Thomasia, 36. Cryptosiphum, 13. tahoense, 13. cucurbitae, Macrosiphum (Siphono- phora), 62. cupressi, Cerosipha, 137. cynosbati, Myzus (Nectarophora), 75. D davidsoni, Myzocallis, 24, 178. dentatus, Laclmus, 45. destructor, Macrosiphum, 66. dianthi, Rhopalosiphum, 85. dirhodum, Macrosiphum (Aphis), 63. discolor, Myzocallis (Callipterus) , 25. Drepanaphis, 18. acerifolii, 18. Drepanosiphum, 17. acerifolii, 18. platanoides, 17. dryophila, Vacuna (Aphis, Chaito- phorus), 150. E Eichocliaitophorus, 33. populifolii, 33. Eriosoma, 148. americana, 148. languinosa, 149, 179. lanigerum, 149. pyricola, 149. Essigella, 44. californica, 44. essigi, Myzocollis, 27. Eucallipterus, 20. arundicolens, 24. flava, 20. tiliae, 21, 178. Euceraphis, 19. betulae, 19, 178. flava, 20. gillettei, 20. euonomi, Aphis, 101. fagi, Phyllaphis, 13, 178. ferrisi, Laclmus, 47. flava, Eucallipterus (Euceraphis), 20. flocculosa, Pterocomma (Melanoxan- thus), 40. foeniculi, SipJwcoryne, 132. fragaefolii, Myzus, 75. fraxini-dipetalae, Prociphilus (Pem- phigus), 146. frigidae, Aphis, 105. frigidae, Macrosiphum, 61. Fullawaya, 35. saliciradicis, 35. G galeopsidis, Phorodon, 81. gillettei, Eueeraphis, 20. glehnus, Lachnus, 47. godetiae, Myzus, 85. gossypii, Aphis, 100. gossypii, Aphis, 105, 179. granarium, Macrosiphum (Aphis), 64, 178. H hederae, Aphis, 106. heraclei, Aphis, 107. heucherae, Macrosiphum (Sipliono- phora), 64. hippophoaes, Rhopalosiphum, 81. houghtonensis, Aphis, 107. howardi, Ehopalosiphum, 86. humuli, Phorodon (Aphis), 79. Hyadaphis, 132. pastinacae, 132. umbellulariae, 133. hyalinus, Myzocallis (Callipterus), 26. Hyalopterus, 130. arundinis, 130, 179. Idiopterus, 56. nephrelepidis, 56. jasmini, Macrosiphum (Nectaro- phora), 64. juglandicola, Chromaphis (Lachnus, Callipterus), 28. juglandis, Callipterus (Aphis), 28. junipcri, Lachnus, 50. L Lachniella, 50. tujafilinus, 50. Lachnus, 45. abietis, 47. alnifoliae, 20, 22. calif ornicus, 44. dentatfts, 45. ferrisi, 47. glehnus, 47. juglandicola, 28. juniperi, 50. 218 MISCELLANEOUS STUDIES occidentalis, 17. oregonensis, 48. pini-radiatae, 48, 178. ponderosa, 48. pseudotsugae, 48. sabinianus, 49. taxifolia, 50. tomentosus, 178. tujafilinus, 50. vanduzei, 50. viminalis, 45. lactucae, Macrosiphum (Nectaro- phora), 65. lactuca Rhopalosiphum (Aphis), 82. laevigatae, Macrosiphum, 62. languinosa, Eriosoma (Aphis), 149, 179. langerum, Eriosoma (Aphis, Schiso- neura), 149. lataniae, Cerataphis (Coccus), 140. latysiphon, Amphorophora, 54, 178. Liosomaphis, 130. berberidis, 130. lithospermi, Aphis, 108. ludovieianae, Macrosiphum (Siplwno- phora), 65. lutescens, Aphis, 117. lycopersici, Myzus (Nectarophora), 76. M Macrosiphum, 57. acerifolii, 18. albifrons, 60. ambrosiae, 60. artemisiae, 61. artemisicola, 61. baccharadis, 61. californicum, 62. chrysanthemi, 62. chrysanthemi, 69. citrifolii, 69. cucurbitae, 62. destructor, 66. dirhodum, 63. frigidae, 61. granarium, 64, 178. heucherae, 64. jasmini, 64. lactucae, 65. laevigatae, 62. ludovieianae, 65. orthocarpus, 66. pisi, 66. pteridis, 67. rosae, 67. rubicola, 77. rudbeckiae, 67. rudbeckiae var. madia, 68. sanborni, 69. solanifolii, 69, 178. sonchella, 70. sonchi, 60. stanleyi, 70. taraxici, 71. tulipae, 71. valerianae, 71. macrostachyae, Symydobius, 38. madia, Macrosiphum (rudbeckiae), 68. maidis, Aphis, 84. maidis, Aphis, 108. mali, Aphis, 120. malifoliae, Aphis, 108. marutae, Aphis, 112. maureri, Myzocallis, 26, 178. medicaginis, Aphis, 114, 179. Melanoxantherium, 41. rufulum, 41. nu.li.i-ti. 43. Melanoxantltus, 40. flocculosa, 40. Micrella, 35. monella, 35. middletonii, Aphis, 115. Mindarus, 150. abietinus, 150. monella, Micrella, 35. Monellia, 29. californicus, 29. caryae, 29. earyella, 30. mori, Aphis, 116. morrisoni, Ne,ctarosiphon, 78. Myzaphis, 134. abietina, 134. rosarum, 134. Myzocallis, 21. alni, 21. alnifoliae, 22. arundicolens, 22. arundicolens, 24. arundinariae, 24. bellus, 24. californicus, 178. castaneae, 178. castanicola, 178. coryli, 25. davidsoni, 24, 178. discolor, 25. essigi, 27. hyalinus, 26. maureri, 26, 178. pasaniae, 26. punctatus, 26. quercus, 27. ulmifolii, 27. woodu'orthi, 27. Myzus, 71. aquelegiae, 73. braggii, 73. cerasi, 73. circumflexus, 74. cynosbati, 75. fragaefolii, 75. godetiae, 85. lycopersici, 76. persicae, 80, 85. rhamni, 76. A SYNOPSIS OF THE APHIDIDAE 219 ribes, 75. ribifolii, 76. rosarum, 134. varians, 77. mncae, 74. N Nectarophora averiae, 94. bacoharadis, 61. californicum, 62. c-itrifolii, 69. oynosbati, 75. jasmini, 64. lactucae, 65. lycopersici, 76. pm, 66. rhamni, 76. ?-osae, 67. soncliella, 70. valerianae, 71. Nectarosiphon, 77. morrisoni, 78. rubicola, 77. negundinis, Thomasia (Chaitophorus) , 36. neomexicana, Aphis, 116. nephrelepidis, Idiopterus, 56. nerii, Aphis, 117. nervatum, Khopalosiphum, 84. nigrae, Chaitophorus, 37. nigronervoaa, Pentalonia, 78. nymphaeae, Siphocoryne (Aphis, Eho- palosiphum), 133, 179. O occidentalis, Lachnus, 47. oenotherae, Aphis, 118. oregonensis, Aphis, 119. oregonensis, Lachnus, 48. orthocarpus, Macrosiphum, 66. padi, Aphis, 94. panicola, Schisoneura, 150. pasaniae, Myzoeallis, 26. pastinacae, Siphocoryne (Aphis, Ey- adaphis), 133. pastinacae, Hyadaphis, 132. Pemphigus, 141. alnifoliae, 146. balsamiferae, 142. betae, 142. calif ornicus, 144. coweni, 13. fraxini-dipetalae, 146. populicaulis, 143. populiconduplifolius, 145. populimonilis, 145. populi-transvcrsus, 143. populi-transversus, 143. radiciooia, 141. ranunculi, 144. venafuscus, 146. Pentalonia, 78. nigronervosa, 78. persicae, Rhopalosiphum (Aphis, Myzus), 179, 185. persicae-niger, Aphis, 119. Phorodon, 79. canZmmwn, 73. galeopsidis, 81. humuli, 79. scrophulariae, 80. Phyllaphis, 12. coweni, 13. fagi, 13, 178. qucrci, 15. quercicola, 15. Phylloxera, 152. popularia, 153. salicola, 153. vastatrix, 152. vitifoliae, 152. Phylloxerina, 153. popularia, 153. salicola, 153. pinicorticis, Chermes, 152. pini-radiatae, Lachnus, 48, 178. pisi, Maerosiphum (Aphis, Nectaro- phora), 66. platanoides, Drepanosiphum (Aphis), 17. pomi, Aphis, 109. pomi, Aphis, 120, 179. ponderosa, Lachnus, 48. popularia, Phylloxerina (Phylloxera), 293. populca, Pterocomma, 41. populicaulis, Pemphigus, 143. populicola, Thomasia (Chaitophorus), 36. populiconduplifolius, Thecabius (Pem- phigus), 145. populifoliae, CJiaitophorus, 33. populifoliae, Pterocomma (Aphis), 41. populifolii, Aretaphis (Eichochaito- phorus), 33. populimonilis, Thecabius (Pemphi- gus), 145. populi-transversus, Pemphigus, 143. populi-transversus, Pemphigus, 143. Prociphilus, 146. alnifoliae, 146. fraxini-dipetalae, 146. venafuscus, 146. pruni, Aphis, 96. prunifoliac, Aphis, 130, 179. prunorum, Aphis, 121, 179. pseudobrassicae, Aphis, 122, 179. pseudotsugae, Lachnus, 48. pteridis, Macrosiphum, 67. Pterocomma, 40. flocculosa, 40. populea, 41. populifoliae, 41. smithiae, 43. 220 MISCELLANEOUS STUDIES 1 Hi iH-tat us, Myzocallis (Callipterus) , 26. pyricola, Eriosoma, 149. querci, Phyllaphis, 15. querci, Schizoneura, 15. quercicola, Phyllaphis, 15. quercus, Myzocallis (Aphis, Callip- terus), 27. B radicicola, Trifidaphis (Pemphigus), 141. ramona, Aphis, 122. ranunculi, Pemphigus, 144. rhamni, Aphis, 76. rhamni, Myzus (Nectarophora), 76. rhois, Rhopalosiphum, 86. Rhopalosiphum, 80. aohyrantis, 80. arbuti, 84. berberidis, 130. corylinum, 81. dianthi, 85. hippophoaes, 81. howardi, 86. lactucae, 82. nervatum, 84. nymphaeae, 133. persicae, 85, 179. rhois, 86. tulipae, 85. violae, 86. ribifolii, Myzus, 76. ribes, Myzus, 75. rosae, Macrosiphum (Aphis, Nectaro- phora), 67. rosarum, Myzaphis (Aphis, Myzus), 134. rubi, Amphorophora (Aphis), 54. rubicola, Nectarosiphum (Macro- siphum) (Amphorophora), 77. rubiphila, Aphis, 122. rudbeckiae, Macrosiphum (Aphis), 67. rudbeckiae var. madia, Macrosiphum, 68. rufomaculata, Coloradoa (Aphis), 137. rufulum, Melanoxantherium, 41. rufulus, Cladobius, 41. rumicis, Aphis, 101. 8 sabinianus, Lachiius, 49. salicieola, Aphis, 123. salicicola, Thomasia (Chaitophorus) , 37. salicicortieis, Symydobius, 39. salieiradieis, Fullawaya, 35. salicis, Siphocoryne, 132. salicola, Phvlloxerina (Phylloxera), 153. salicti, Cladobius (Melanoxan- therium), 43. sambucifoliae, Aphis, 123. sanborni, Macrosiphum, 69. Schizoneura, 148. amerioana, 148. lanigerum, 149. panicola, 150. querci, 15. scrophulariae, Phorodon, 80. senecio, Aphis, 123, 179. setariae, Aphis, 124. Siphocoryne, 131. avenae, 84. capreae, 132. conii, 133. foeniculi, 132. nymphaeae, 133, 179. pastinacae, 133. salicis, 132. xylostei, 133. Siphonophora, 60. acerifolii, 18. ambrosiae, 60. artcmisicola, 61. chrysanthtmi, 62. circumflexus, 74. cucurbitae, 62. heucherae, 64. ludovicianae, 65. solanifolii, 69. sonchella, 70. tulipae, 71. smithiae, Ptorocomma (Chaitoplwrus) , 43. solanifolii, Macrosiphum (Siphono- phora), 69, 179. sonchella, Macrosiphum (Siphono- phora) (Nectar opliora), 70. sonchi, Macrosiphum, 60. sorbi, Aphis, 108. spiraecola, Aphis, 124. spiraeella, Aphis, 125, 126. stanleyi, Macrosiphum, 70. Symydobius, 37. agrifoliae, 38. chrysolepis, 38. macrostachyae, 38. salicicorticis, 39. tahoense, Cryptosiphum, 13. taraxici, Macrosiphum (Aphis), 71. taxifolia, Lachnus, 50. tetrapteralis, Aphis, 125. Thecabius, 144. californicus, 144. populiconduplifolius, 145. populimonilis, 145. Thomasia, 35. crucis, 36. negundinis, 36. populicola, 36. salicicola, 37. viminalis, 34. A SYNOPSIS OF THE APHIDIDAE 221 tiliae, Eucallipterus (Aphis, Callip- terus), 21, 178. tomentosus, Lachnus, 178. Toxoptera, 129. aurantiae, 129. aurantii, 129, 179. Trifidaphis, 141. radicicola, 141. Tuberolachnus, 45. viminalis, 45. tujafilinus, Lachnus (Lachneilla), 50. tulipae, Macrosiphum (Siplionophora) , 71. tulipae, Ehopalosiphum, 85. U ulmieola, Colopha (Brysocrypta) , 148. uhnifolii, Myzocallis (Callipterus),27. umbellulariae, Hyadaphis, 133. Vaeuna, 150. dryophila, 150. valerianae, Macrosiphum (Nectaro- phora), 71. vanduzei, Lachnus, 50. varians, Myzus, 77. vastatrix, Phylloxera, 152. venafuscus, Prociphilus (Pemphigus), 146. virburnicolens, Aphis, 126, 179. viminalis, Aretaphis (Callipterus, Chai- tophorus, Thomasia), 34. viminalis, Tuberolachnus (Lachnus) (Aphis), 45. vinoae, Myzus, 74. violae, Rhopalosiphum, 86. vitifoliae, Phylloxera, 152. W woodworthi, Myzocallis, 27. X xylostei, Siphocoryne, 133. yuccae, Aphis, 128. yucoicola, Aphis, 128. MUTATION IN MATTHIOLA BY HOWARD B. FROST [University of California Publications in Agricultural Sciences, Vol. 2, No. 4, pp. 81-190] MUTATION IN MATTHIOLA BY HOWARD B. FROST CONTENTS PAGE Introduction 81 Genetic literature relating to Matthiola 84 Methods 85 Experimental data 89 The occurrence of apparent mutants 89 Characteristics and heredity of mutant types 92 1. The early type 92 2. The smooth-leaved type 118 3. The large-leaved type 125 4. The crenate-leaved type 127 5. The slender type 135 6. The narrow-leaved type 141 7. Miscellaneous aberrant types 143 8. Some probabilities of random sampling 145 General discussion 153 Summary 159 Literature cited .. .. 161 INTRODUCTION It is hardly safe to use the term mutation without first defining it. In this paper it will be taken to mean a genotypic change, or a change in essential hereditary constitution, due neither to immediate cross fertilization nor to segregation in a heterozygous parent. No attempt will be made to restrict the term to any of the known or supposed types of such genotypic change; a limitation of this kind, which restricts the generally accepted sense of a widely used term, seems to tend to confusion rather than to clearness. fan 1'iM MISCELLANEOUS STUDIES If we use the term factor mutation,2 (Babcock, 1918) where the cytological change occurs within a locus, transforming a factor into a different factor, two analogous terms will apply where the cytological change is external to the locus. When the cytological change consists of a loss, reduplication, or transposition of one or more loci it may be called a locus mutation, and when the change consists in such phenomena affecting a whole chromosome it may be called a chromo- some mutation. If the term mutation is applied to the cytological change itself, the last two types of mutation may be grouped together as extralocus mutations, while the first type consists of intralocus mutations. Examples of factor mutation are white eye in Drosoi>liild, and probably the rubrinervis type in Oenothcra; an example of locus mutation is (possibly) "deficiency" in Drosophila; and examples of chromosome mutation are Oenothera gigas and 0. lata. It is now evident that the immediate problem with Oenothera relates to the mechanism of heredity in the genus. There are two sharply opposed views. One is that recently emphasized by Atkinson (1917, p. 254), when he says, "The evidence from Oenothera cultures points more and more to the conclusion of Shull that 'a hereditary mechanism must exist in Oenothera fundamentally different from that which dis- tributes the Mendelian unit-characters.' ' The opposing view is represented by Muller's (1918) strictly Mendelian explanation for Oenothera, based on "an Oenothera-like case in Drosophila" ; he says. "The striking parallel between the above behavior and that exhibited in Oenothera makes it practically certain that this, too, is a complicated case of balanced lethal factors." A notable feature of the extensive genetic study of Oenothcra is the lack of progress toward any definitely supported explanation of its hereditary mechanism, which is not Mendelian. The only definite non-Mendelian hypothesis of chromosome behavior so far proposed, aside from "merogony" and other hypotheses (Goldschmidt, 1916) apparently possible but not proved for Oenothera, which assume loss of chromatin after fertilization, seems to be Swingle's (1911) "zygotaxis, " proposed for the apparently parallel case of Citrus. This suggestion that Ft hybrids may differ, apart from non-uniformity of the P! gametes, because of the establishment of permanently differ- ent arrangements of the chromosomes in the fertilized egg, still seems to be purely speculative. "With more or less "Oeiwth era-like" cases in other genera, the only definite progress in analysis seems to have resulted from the assump- 2 Muller (1918) has recently used point mutation in the same sense. f82] MUTATION IN MATTHIOLA 225 tion of Mendelian segregation. With Oenothera itself, the trend of the evidence tends to favor this form of explanation. This fact is strikingly illustrated by two papers of de Vries (1918, 1919) which have appeared since the present paper was written, especially as Muller's (1918) complete report on the beaded- wing case in Drosophila (see especially pp. 471-474, 489, and 498-499) indicates that de Vries had hardly yet realized the full possibilities of the balanced- factor hypothesis. In the light of Muller's masterly demonstration of these possibilities, we may be confident that "mass mutation" is merely ordinary segregation, and that the "unisexual" crosses of Oenothera are really "Mendelian" in their essential phe- nomena. Some difference of usage respecting the inclusiveness of the term Mendelian may be involved here, it is true, since apparently de Vries would apply it only to cases where strictly homologous factors are opposed in homologous chromosomes. Since, however (Muller, 1918), there are good reasons for expecting the occurrence of grada- tions of similarity and of synaptic attraction between opposed loci, and hence of gradations of linkage, the criterion of Mendelian behavior should obviously be the occurrence of segregation between homologous chromosomes, whatever their degree of similarity or amount of cross- ing over. We have no reason to assume that an "unpaired" factor in a parent would so divide as to be included in all gametes; on the other hand, we have learned of a mechanism capable of insuring, in certain particular cases, the inclusion of a certain factor or group of factors either in every functional gamete or in every viable zygote. No doubt, as Davis (1917) says, "A great forward step will be taken in Oenothera genetics when types of proven purity have been established . . . ." Meanwhile, cases of "Oenothera-like" heredity in species known to possess the Mendelian mechanism deserve most thorough investigation. Special interest consequently attaches to the peculiar inheritance of certain apparent mutations of the ten-weeks stock (Matthiola anmia Sweet), a species in which various character- istics are typically Mendelian. A remarkable series of aberrant forms in this species3 has been briefly discussed in two preliminary com- munications (Frost, 1912 and 1916), and the present paper gives a fuller account of the same phenomena.4 sin the variety "Snowflake, " a glabrous, double-producing form with white flowers. * While this paper was in press Blakeslee and Avery (1919), have reported the occurrence of apparent mutations in Datura, which seem to be similar in almost every respect to those here discussed. F83] 226 MISCELLANEOUS STUDIES Apparent mutants were first found in the course of work on another problem, the relation of temperature to variation (Frost, 1911), conducted at Cornell University. Studied incidentally at first, these new forms were later given special attention. About nine thousand plants, of which about two thousand were progeny of mutant-type parents of peculiar heredity (nearly one-fourth of the latter representing crosses with Snowflake), have been examined altogether. Some of these plants have been grown at Riverside, where hybridization studies with mutant types are in progress. The present account considers the origin and characteristics of these types, their inheritance with self pollination, and the rather meager available data relating to their behavior in crossing. In connection with the work at Cornell, special acknowledgment is due to the late Professor John Craig, and to Dr. H. J. Webber and Dr. H. H. Love. Facilities for work were furnished by the depart- ments of Horticulture and Plant Breeding of the New York State College of Agriculture. GENETIC LITERATURE RELATING TO MATTHIOLA The work of Correns (1900) on Matthiola furnished one of the earliest confirmations of Mendel's law, and also pointed to complica- tions not found by Mendel. The earlier literature, according to Correns, gives no indication of the study of Matthiola hybrids beyond the first generation. In his later paper on aberrant hybrid ratios, the same author (1902) discusses complications in maize and in Matthiola. After referring the deviations found in maize to selective pollination, he considers a suggestion of de Vries relating to environmental modi- fication of Mendelian ratios, and himself suggests the possibility of selective elimination of gametes. He says (pp. 171-172), "Solche Einfliisse brauchten nicht alle Sorten Keimzellen des Bastardes gleich- massig zu treffen, sondern sie konnten eine Sorte starker angreifen als die andere." Von Tschermak (1904, 1912) lias made extensive studies of Matthiola hybrids, considering mainly, as did Correns, pubescence and flower color. The latter of these papers on hybrids in the genera Matthiola, Pisum, and Phaseolus represents a careful analytical test of the "factor hypothesis" of segregating inheritance, leading to the conclusion that the applicability of this hypothesis is strongly con- T841 MUTATION IN MATTRIOLA 227 firmed by the results secured. This work, with that of Miss Saunders. leaves no possibility of doubt that the typical Mendelian mechanism is present in Matthiola. The most extensive genetic work on Matthiola is evidently that of Miss Saunders, reported by herself (1911, 1911a, 1913, 1913a, 1915, 1916) and by Bateson and Saunders, with others (1902, 1905, 1906, 1908). This also is work on heredity in hybrids, with special emphasis on the factorial interpretation of the various complications relating to pubescence and to ' ' doubleness " of flowers. Goldschmidt (1913) has explained the inheritance of doubleness by sex linkage and lethal action of a femaleness factor in pollen formation, and his interpretation has been criticized by Miss Saunders (1913). I (Frost, 1915) have presented a somewhat different lethal- factor scheme, and Miss Saunders (1916) has since restated her views and criticized mine. Muller (1917) has cited the inheritance of doubleness as a case of "balanced factors," in apparent agreement with my formulation. Apparently no one but the present writer (Frost, 1912, 1916; see also review by Bartlett, 1917) has reported experimental evidence of any notable tendency to apparent mutation in the genus, although de Vries (1906, p. 338) mentions the occasional occurrence of vigorous, rigidly upright individuals (a gig as type?), known at Erfurt as "generals," and refers to the rare mutative occurrence of single flowers on branches of double-flowering plants. Doubleness, and color variations in considerable number, have evidently arisen under culti- vation, probably through mutative changes. METHODS The general cultural methods employed for the first three genera- tions have been very briefly described elsewhere (Frost, 1911). The plants of the first four years were grown in pots in the green- house. The plants of the first generation came from one or both of two packets of commercial seed planted in the fall of 1906, and all plants in the later cultures (possibly excepting series 18) were descendants of these. The cultures will in general be designated by the year in which the seed was sown ; the field and greenhouse cultures of 1911 are indicated by 1911F and 1911 H respectively. Part of the seed planted, especially in 1908, came from unguarded flowers. The seed lots where this occurred will be indicated in the [85] 828 MISCELLANEOUS STTIn tabulation of parental data by italic figures, while protection possibly defective will be indicated by an asterisk. It is not probable that much vicinism occurred in the greenhouse cultures, since this plant is well adapted to self fertilization. In the first year's (1906) cultures the plants in each experimental environment were separately numbered. Each plant was designalnl by its number preceded by two letters indicative of the environment. For greenhouse temperature these letters were C (cool), M (medium temperature), and W (warm) ; for potting soil3 they were S (sand), L (unfertilized "loam"), and G ("good" soil, fertilized). Thus CS1 CS2, WG9, etc., were pedigree numbers of the first generation, and CG2-M8 and WG9-C10 of the second generation. A few syncotyle- donous plants outside the regular cultures of 1907 were called WG9- synl, etc. For the work at Riverside a new system of numbering was adopted, better suited to ordinary pedigree cultures, and the numbers from this system are used below in the individual treatment of all but one of the mutant types ("early"). This is essentially Webber's (1906. p. 308) system, except that each initial or P^ individual of a series is indicated by a letter; a full description has been published (Frost. 1917). With Matthiola each type or cross between two typos that is tested receives a series number, the apparent mutants themselves always being taken as the initial individuals of their selfed series. The cultures of 1908 included progeny of various parents, one being WG9-C10, an early and few-noded plant suspected of being a mutant. The cultures of 1910 consisted of a second-generation test of WG9- C10, and a first-generation test of other possible mutants, with control lots. The plants were all grown on one bench in one greenhouse (house C), from thirty lots of fifteen seeds each, lots 1—17 relating to WG9-C10. The parents descended from WG9-C10 (see table 7) w.-n- selected as those with fewest internodes, a medium number of inter- nodes, and most6 internodes in each house of the 1908 cultures, earli- ness of flowering being considered when parents were alike in number of internodes. The control parents were both few-noded and many- noded. relatively to their sibs. In 1911 eighty progeny lots were grown in the field at Ithaca. Lots 1 to 28, transplanted from the greenhouse, paralleled the test of o Soil experimentally varied only in the 1906 cultures, temperature varied in the two following years also. « For house M, not the highest, which was exceptionally high, but the next to the highest. f86] MV TAT ION IN MATTHIOLA 229 WG9-C10 made in 1910-11 ; all available progeny of WG9-C10, except the crenate-leaved apparent mutant WG9-C10-C10, were tested, with check lots between as before. Soil differences and unavoidable differ- ences between lots in time of transplanting combined with hot weather and drought to reduce the value of the results. The remaining fifty- two lots, all field-sown, included a further test of the heredity of aberrant types other than early. Most of these lots, however, were progeny of Snowflake parents, grown to obtain evidence on the relation of temperature to mutation and on the inheritance of doubleness of flowers, and therefore the results are not reported here. The 1911H cultures constituted a coldframe and greenhouse prog- eny test of mutant types, mainly in the second generation, the plants being grown in flats. There was added in 1912-13 a small greenhouse test bearing on the supposed mutative origin of WG9-C10, in view of the apparent possi- bility that "WS1 or "WL10, in the same house with the unbagged WG9, might have been heterozygous for the early type — cross pollination then giving the apparent mutant. Further progeny tests of the mutant types have been made in the field at Riverside, beginning in the fall of 1913. Mainly on account of the unsuitability of the usually hot and dry climate of River- side, the cultures have been largely experimental and always on a small scale, and germination or development has sometimes been un- satisfactory. Cultures have been started in October, November, January, and February, and a trial culture in progress at the time of writing was started in August. Some of the plants of the 1915-16 cultures were kept until the summer of 1917, and many of them flowered for the first time when about a year old. In the cultures of 1913, growth was largely unsatisfactory, and with part of the plants aphid injury interfered more or less with the classification of types. In the cultures of 1914, the seeds were largely lost through toxic effects favored by very shallow planting (as at Ithaca) and strong evaporation from the soil. In subsequent planting, the seeds, planted singly in small paper pots, were dropped into relatively deep holes punched in the soil, and covered with sand. The only field-grown plants closely resembling those grown in the greenhouse at Ithaca, it may be noted, have been those of the 1917 cultures, grown in a lathhouse with added shade from muslin. In the cultures of 1915-16, with partial shade and more frequent irrigation than before, development was in general good; but even [871 230 MISCELLANEOUS STUDIES S 4) t "s 8 8 S ! j I I-H -H 4i 1 ° « > 5 - 1 •8 s 1 e a §• 1 3 s •*< 3 ««a « . & s -u V oj bo 5 as J « ^ - | 0 Si V ! ai«l A".iaA i 1-1 : ti 1 >- efl No g ^ - S 9 5 1 1 3 o g to aberran .1 )i:| A'.I.I A : H inns pin: MII u.i -uinu saAnai r-t i— 1 A 8 * s r^ * > 00 S o ?>5 1 belonging -siui sdi^-jtoq i— 1 i-H ft 0 g - a .f c »T B -g ® T3 rt g oj £. Bi | O g £' 'H _0 1 43. i— i ': i— i i— i 1 ^ 1 S 5 ^ 2 - §, " & e rH § H § « t | Numbers adA-j |— « * o 5 S s -i 1 v-' bo ^ 5 o o -^ S rt S a * El S o i 5^ sasa i— i i i— i ^> CS *J _ fl ^ M o Q> • ~T O • *4-l to bo a/ i-i "s g p^SU, V 1— 1 1-H I— 1 CO I-H C^ •^ rt ^ Q) oi _ C? "T? O -4^ rK ™ sig s,^ s E J3 0 .2 -g .3 A ^ °6 <^j paA^Us CC : : C^ iO I-H i— i CC ^s. fi u x t« o o £ ,2 es _jj ^e ft r— * .2 -S >> ^ £ a S * » t? a *H <+-, o 1 s s| 11 a *O 00 ^f l^- "^f OO O OO CO CO I-H t>- O Tf ^H(M Parentage > > -fa |«5 o^ g, •S § | o | 2. • S * u " * S F881 MUTATION IN MATTHIOLA 231 here the mutant types, with one exception, often failed to grow satis- factorily or to set seed. Infection, probably by Fusarium, evidently was the cause of the death of many of these plants in their second season. With all cultures grown after (probably) those of 1906, special care was taken to secure random samples of seed, and after 1908 no plants were rejected. The only exception to this statement is the rejection of one pot out of every fifteen, by number and systematically, in the first twenty progeny lots of 1910. For the earlier cultures, a certain amount of selection must be recorded, as follows. In 1906 the small and the largest plants were omitted at potting, and probably any weak and abnormal seedlings had been omitted at the preceding transplanting. In 1907 all markedly weak, late, or abnormal seedlings, as determined mainly by the appearance of the cotyledons, were omitted at the first transplanting; and the same was done in 1908, except that certain lots from old seed were unselected.7 These last lots were arranged at transplanting in such a way that the weak and abnormal plants came at the end in each lot. EXPERIMENTAL DATA THE OCCURRENCE OF APPARENT MUTANTS In the cultures of 1906, 88 plants were grown to maturity, none of these being suspected of mutation. In the cultures of 1907, among 170 plants one striking variant appeared; this plant, WG9-C10, was exceptionally small and early in blooming. In the cultures of 1908, 714 plants were available, including ap- parent mutants in several hereditary lines as indicated in table 1. A striking feature of the results is the scarcity of apparent mutants among the seedlings classed as strictly normal at transplanting; prob- ably the scarcity in the preceding years was due mainly to the rejection of abnormal seedlings (see "Methods"). The first, second, and fourth of these forms have been common in later cultures, while the third and fifth have been rarer; the last three, if seen at all elsewhere, have not being recognized as belonging to the same types as these three plants. 7 One tiny plant from WG9, probably not viable, was discarded. T89J 232 MISCELLANEOUS STUDIES Table 2 shows the numbers and percentages of apparent mutants found in the cultures of 1910 and 1911F. Since the early type seems to differ from Snowflake only in size and earliness, and is probably inherited without special complications, the available progeny of early- type parents are included in the totals. The progeny of all parents recognized as belonging to other aberrant types are omitted. The second column under ' ' Percentage of mutants ' ' omits doubtful types and individuals, but includes some individuals for which some doubt was indicated in the original records. One rare type of 1911, large- TABLE 2 Aberrant types: occurrence among progeny of Snow flake and early parents. Apparent selective elimination at or after germination in field-sown cultures." Cultures Progeny examined1' Percentage of apparent mutants All counted Doubtful omitted Greenhouse, 1910 338 5.03 =b .82C 4.14 =b .77 Field, 1911, seed house-sown 2072 5.31 db .33 4.63 ± .31 All above 2410 5.27 ± .31 4.56 ± .29 Same,Snowflake par- ents only 1364 4.33 ± .41 3.74 ± .38 Field,1911,seed field- sown (parents all Snowflake.) 3927 2.34 ± .24 1.55 ± .22 • Germination in greenhouse-sown lots, counting only plants examined for type, 93.2 per cent; in field-sown lots, 45.1 per cent. "Including some plants of uncertain type, indicated for some lots (when apparently not Snowflake) in tables 1 and 3. c For the calculation of these probable errors the percentages on the third line are used as p. leaved, here omitted, has proved to be genetic, but its determination in these cultures was in general uncertain. A stricter criterion for the second column, elimination of all individuals not considered posi- tively determined, was used in the calculations for the tables for the inheritance of the separate mutant types. Evidently the more rigorous field conditions of 1911 eliminated many of the "mutants'7 at or soon after germination. The "coefficient of mutability" with good germination, as was the case with the un- selected cultures of 1908, seems to be near 5 per cent, a surprisingly high figure if immediate true mutation is responsible. Before the aberrant types are considered separately, we may examine (table 3) a detailed illustration of their occurrence in larger cultures. It seems probable, from this evidence, that any descendant of "WG9 was capable of producing any of the mutant types so far [90] MUTATION IN MATTHIOLA 233 1 1 rt- * P »- |1 co £ 1 1 c ^> 3 T3 9 P 5 O 3 P 3 03 'S !^ i* Oi*>COtOt-'OcOOO^arf».COtOi-'OCOO5O>*>'COO5C»^IO5OiGC 4». o> GO ^j to oi co ^ w OT ^ : to i— ^ w to i— £r "^ O H-> : ri^ O t*>- 00 ^ Generation 3 1— > o o to o -J to O5i-'tO*.OitOOiOiOOO^I^JOOO5OOOOOCDCOOOCOOiOOOiVIO^J Total progeny of determinable type H- ' g to ~4 • )-* to H* • : h->h-' to to i— ' : to : tOCOCOt-1: i— ' i— ' i— ' h-> )-» Smooth-leaved Progeny evidently belonging to aberrant types -u co co : :h->:i— 'it—": : t— ' i— ' *—» : : : t— » : H^ i— ' : :::: Small-smooth- leaved ^1 ^1 i— i 02 -4— to : : : : H-» >— ' : : to : i— ' : i— ' i— > : : i— ' i— > i— ' : Crenate-leaved 1— » o ^ Semi-crenate- leaved o Oi - Pointed-crenate- leaved o Oi i—" Medium-smooth- leaved CO ^J to o : : : OitO: : : *—> to t— ' : .' H- » : tO H- ' i— ' : i— ' : i—i i— ' : : h- ' : : Narrow-leaved rf* 00 o :•:::: to: ::::::: H-> h-- : : : : : CO H-> : to Narrow-dark- leaved — *• CO I—1 t— « Slender ^: : : : : : ^^ : :::::::::::::::::: — 0 to h-" : : : ::::::::: i— >::::::::: Small-convex- leaved 1— > CO 4*. Compact b Cn M Curly-leaved H- ' rf»- co . . ^. ...'-... •-* Pointed-light- leaved • • ->s -*: : : "O O Oi H- » *- Large-leaved -* ^ CO H-1 1— ' I—* Medium-large- leaved -o • • — o -o • h- > *; CO to H- Large-thick- leaved •^s -o • • O Oi M I—* Small stout- capsuled ^s o Oi I— ' h^ Jagged-leaved -c Cn CO t— » 0 OOO4^(»C^tOOOiO5tOO5*-rf»-COhP>.tOH-'O500OiCOrfi.COtOOiOitOCO All counted > #>• C3 CO CO c^ O5OCOOOOitOOCOOitO4>-CO4».tO4i-tOH-'Oi §3 ^^-s o o o o 1— » /^ thnsi I??? ffisfffgi1 * M i a (Snowflak 3 eneration g • p^-2->2' -£- ST' (5 -2^ — (6 (B fD (6 to 3 ^^ ^ N~^ 68 p ^_^ i - ® H- O *^ ' O 60 CO CO 2 ^ »? 3 cocc^sgccoiaitTjMp^^^HM^220^^ H"S^ O m I'll o 1 1 i ^ isl 1 1 ^i i 1 ^^1 1 i tO^It-'OO CO rfi-VI *. tO 00 M O5 *-t CO to 13 i3 Oi I— ' GO Oi rf» tO 4^ O C5 tO O O Cn CO O .— h^ S ?" 3 5" E )__A_% ^>~- ^ ^ _x . ^J^-,. «_ ^r-*—, 3' SJ" 31 ^ "^ p •. -<| O5 ~4 Z O o « H- 00 0 tO CO O M 50 45 40 35 30 28 in 16 10 5 Singles — — Doubles _ _ _ • • • • • • • • • • • _-_ M3 M4 C2 Co Cl 1 1 1 1 1 M6 M9 C5 M4 M2 M7 C3 C7 VV6 Wo W10 M5 MS 1 1 1 1 1 1 1 1 1 1 Cl CIO 1 1 1 CIO C9 CIO C9 1 1 WG9 Ancestry Chart 1. Cultures of 1910. Internodes: parental values and progeny means (respectively shown by dots and lines) for progeny lots 1 to 17, omitting aberrant progeny. Parental values should be compared only for the same house. Table 7 gives the available data for the parents of the 1910 cultures, and the numbers of progeny available for quantitative data. The order of the pedigree numbers here is the same as that of the progeny lots on the greenhouse bench. For convenience, the 1910 tests of other mutant types, together with tests of several Snowflake parents, are included in the table (lots 18 to 30). F98] MUTATION IN MATTHIOLA 241 The plants were grown in house C of the previous work. Two or three plants (one shown in fig. 25) were extremely vigorous, pre- sumably because of some accidental soil difference; aside from these, a few apparent mutants, and a few plants otherwise abnormal, the plants were fairly uniform except where heterozygosis was to be expected. The data for time of flowering, as with the 1908 cultures, show the same main features as the internode data, and only the latter will be considered in detail. The types were again more widely different in internodes than in earliness, a fact which seems to indicate that the early type grows more slowly than Snowflake. So large and so regular are the differences in internodes that the means of these very small lots seem worthy of presentation (chart I).11 Apparently the few-noded character was carried, among the nine parents descended from WG9-C10, by all except the three parents having the highest numbers in their respective houses. Tables 8 and 9 give the internode frequencies for the singles and doubles respectively, by separate progeny lots and by groups of similar ancestry. The range of variation for the check lots, omitting the indicated apparent mutants and other apparently abnormal plants, is rather surprisingly small, as is the case with the cool-house cultures of 1908. The three late progeny of WG9-C10 give lots closely corre- sponding in range to the check lots, only one individual falling below the range of the combined check lots. The six early and medium progeny of WG9-C10, on the other hand, give distributions of far greater range than do the check parents, extending to much lower values. Tables 10 and 11 give the ordinary statistical constants for the grouped lots. The mean number of internodes, for both singles and doubles, is about 25 per cent lower in the progeny of the six few- noded parents, the difference being not far from ten times as great as its probable error. The increase in variability with the progeny of the early parents is also striking, and the difference is about five to six times its probable error. With time to flowering, it may be noted, the differences are similar to those with internodes, but somewhat less marked in the case of the mean ; the flowering data are not given here. It is plain that the previous conclusion as to the heterozygous nature of WG9-C10 is sustained. The elimination of the apparent mutants n Calculated with the apparent mutants and four other apparently abnormal plants eliminated; see tables 8 and 9. T991 242 MISCELLANEOUS STUDIES S rO 1 e 'C O «9> 1 O g sow a ° • o c J S "2 o o lS .2° § S ^=03 »- H I o ^ [100] 243 ce «c J o — "° o o « 5 .S ?3 "S § O 0 •~ 9 rQ * g 01 & 00 03 3 qj © 1 8 ^ « 2 % 10 .2 'S •£ rrt SD ^ ts % •S » ^o 0 s o 1 is ^ T3 * •£ 0 « .O Q^ -*J « A O 1* !g3§ L to 5 ? a 2 ** _S >». i* ft. ^ :•»-• ::::::::::::: -*J ^5 i 6C - cj o e o •^ t. -C — ss. O) O rt "^ *w pij O O3 3 o £ PnS . -"S C8 O P^ « rO ^ on V> X ^ O S i_ as t* ^^H ^S O o N g 0 5 s a ^-^^ tw> s Tf c ® S3^^ s£ a 'a * ^ cs ro 6 05 ? % «J oil • . . .^_ 2 .PH 9 •& PL, S ::: i— i ::::::::::: S).S §0 £ O co ^H ^_ ^Ig "go S o> « ^H ::::::::::::: 1-1 1 g > ^ >> ^ 0 ^^ O ^- <—• O p Kl ^O "j^"^1 ^ '^•'"^ CO ~S-o •ib-S ** j5 « 3 a C6 9 Z? >< ^A_ >*< _^^ 0 | 1 1 %$ o' g gr (O £ <^ * 1 ><^ ><^ o |i ~'§.Mtrlt7l ""^ 2 H t^tr1 p o a H-Srl o' g i-< r*- - t^T ^ ^ at -I, I f c*- S. ^ CD CO S ^ §.' o* ^ ll 1 1 to 1— ' t-«cooo to en 00 *-4 ^ H-> Cn O D -^ 4^ tO Co Cn ^^ (D ft O QJ 3 n Oj «> a ll to to to to to Cn Cn O OS Os to to to to to to co co I— > --j co i<^ en co rf». Cn O 00 s g4 CnOO tO*-O OS O O ** Co ^ a ns* cS H- If If H- If H- If If If If v> s ^ •— to ^ to to 00 tO CO COM toco OS tO OS *-00 »— to to II. 3 <§ s" ° CO &4 CO CO 4x tO 10 Cn 4- Cn to CO If? CO tO Cn H- CD i— to cn rf*. Cn too 101- co oo *•• H-CDM a. as 2 P Oi If If H- If H- H- If H- H- If S'o. S ll § t-i H- ' 00 tO 1— > co oscn Oco I— tO 00 CO OOCD tO So" 0 --«> S1 «. i-» h-> tO I— ' h- ' (-» to i-« Cn to H- 00 i— 0000 OSOOh-" O ^ gs^gs o2 to to bs I-* OS OO 11 «. 1 JS'2. H- H- If If If H- H- If If If gl 1 h- > tOH- o in OS M M M OSM O O •*! *^* to to ^ oo oo 0000 00 tO^l [103] 246 MISCELLANEOUS STUDIES C^ W ^O &3 O C5 COO CO -^ QCCD 0 a ^-»^H ^-( $ | n ti ij n n ij n n 11 "n n n i c? « rocor- co"3W o > O* CN x 0 Tf OOO CO 00 O (N IM 00 O O5 >O i-l ^H CO O C*l CO »~H C^ CO 3 "H a 1 « •tt '% •H -H -H -H -H -H rQ K 0 COCO lO CO I-H (N *> •S r-l C § cogo coo^. 1 B 1 •H -H -H -H -H -H 3 (N O b- C2o § B V—Y—/ —V—' »a ad "5 -u O -* O5 O5 CD EJ o o a> a "o ^* ^ c « M sa[8uig sajqnoQ U04] MUTATION IN MATTHIOLA 247 and the other abnormal plants presumably gives a better comparison as to mean and variability, but the conclusion is the same in either case. The three many-noded (late) parents descended from. WG9- C10 give no definite indication of being genetically different from the "check" lots not descended from WG9-C10, while the variability con- stants are sufficient, taken alone, to make probable the genetic differ- entiation of the fewer-noded progeny of WG9-C10. Apparently all the fewer-noded progeny of WG9-C10 that were tested — seven, when WG9-C10-C10, a crenate-leaved apparent mutant (tables 12 and 13), is included — were either simplex or duplex for presence of an earliness factor or factors. The variability of all the thirty progeny lots, taken together, is high, as might be expected, though decidedly below that of the progeny of early parents. This high variability is due only in very small part to the progeny of the five or six supposedly mutant parents; the last thirteen lots, alone, are much less variable than the mixed early lots. The portion of the cultures containing these progeny lots from aberrant parents was conspicuous for irregularity of germination, and, on the whole, a relatively low rate of germination. A few of the last thirteen lots give more evidence bearing on the origin of WG9-C10. The early WG9-syn3-M10 (tables 12 and 13) gives no evidence of genotypic differentiation from its ordinary sib, WG9-syn3-Mll ; WS1-W216, another phenotypically early parent, also failed to transmit earliness 'to its progeny. CG2-C2-C6, on the other hand, although itself an ordinary plant, shows a rather sus- picious tendency to the production of early and few-noded progeny, but better evidence would be required for any positive conclusion. WG9-C10-C10 appears, from the data in tables 12 and 13 and from observation of the flowering of plants of the next generation in the 1911H cultures, to have been heterozygous for the early type, as well as for the crenate-leaved type. We find in this test no definite indi- cation that the early type has appeared elsewhere than in WG9-C10 and its descendants. The F2 progeny of WG9-C1, an abnormal plant whose Fx progeny were unusually and uniformly early but not few-noded, have been included with the other check lots without question. This treatment seems justified by the flowering data, which do not indicate any repetition of the precocious development of the first-generation plants ; the peculiarities of the Fl cultures, if not a mere cultural accident, presumably depended on the very abnormal development of the parent, fl05] 248 •MISCELLANEOl .S ,s777>/A',s TABLE 12 1910, greenhouse, lots 18 to 30. Number of main-stem internodes below first flower-bearing node. Frequency distributions for singles.* Gen. 1 CG2 WG9 wsi WL10 Gen. 2 C2 W4 syn (M) 3 C228 W2 CIO W2 W7 W216 W?25 W220 Gen. 3 Inter- nodes 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 C6 W3 C17 M10 Mil M7 CIO W2 C5 1 It 1+ It 1 i i 1 1 1 1 1 1 1 1 2tt It 1 "2" 3 1 2 4 "l" 2 2 3 3 2 1 1 3 1 2 2 1 1 1 1 i "it 1 1 1 1 1 It 1 1 1 1 It 1 It It • See table 7 and notes to tables 5 and 8. TABLE 13 Same as table 12, for doubles." Gen. 1 C 32 • W G9 W SI WL10 Gen. 2 C2 W4 s yn (M) 3 C228 W2 CIO W2 W7 W216 W225 W220 Gen 3 C6 W3 C17 M10 Mil M7 CIO W2 C5 Inter- nodes 16 1 17 2 18 19 1 20 21 3 22 1 2 2 23 1 2 It 3ft 1 24 2 1 It If 2 25 4 1 3tt 2 It If 1 1 1 26 2 2 2 1 2 If 27 2 1 2 2 3 3 1 2 28 1 1 1 2 5 1 29 2 1 1 2 30 3tt 31 32 1 1 It 33 34 1 1 Ances- try • See table 7 and notes to tables 5 and 8. [106] 249 with its aborted main axis and very late production of a flowering shoot. Table 14 shows the general plan of the house-sown field cultures of 1911. The progeny of "WG9-C10 were arranged as before in the order of their numbers of internodes for each house of the 1908 cul- tures, beginning with the lowest numbers. The parental values for flowering and internodes are the values indicated by "$" in tables 5 TABLE 14 1911; field, plants transplanted from greenhouse. Ancestry, seed, and numbers of progeny* Lot Ancestry Seeds sown Number of plants alive 33 days after sowing Numbers of plants for data on mutation and flowering Gen. 1 Gen. 2 Gen. 3 Totalb Singles Doubles 11 fier /C8 80 79 77 34 43 2/ CyO \ CIO 71 71 70 36 34 • ] fC2 80 80 79 39 39 4 [ 5f CIO j C5 1 C8 80 80 79 79 78 78 40 35 38 . 43 6J LCI 80 78 76 36 40 7\ /"*ic /W18 80 79 77 37 40 8J C5 \W24 80 76 75 41 34 91 'M4 80,88 77 76 30 45 10 M9 80 80 78 36 41 11 CIO M6 80,63 77 77 34 42 12 k M2 8Q,71 78 77 36 40 13 M7 80 80 80 37 42 14 J M8 80 74 70 33 37 WG9 15 \ /T» /C3 80 78 78 30 48 16 / uy \C7 80 76 75 32 43 17] 'W6 80 74 70 31 39 18 W4 80, M 70 65 26 38 19 Wll 80 78 76 34 42 20 W9 80, 19 76 72 24 47 21 CIO W5 80 79 75 33 42 22 W8 80, 14 76 74 36 36 23 W7 80 75 72 32 40 24 W3 80 73 71 37 34 25 J W10 74 72 66 32 34 26 CIO 80 60 59 27 32 27 \ /~Tk / W10 80 74 73 33 39 28 / uy \W24 80 80 78 32 45 a For plan of arrangement and parental data, see page 86 and tables 5 and 6. Seeds from unguarded flowers are indicated by italic figures; where two numbers are given the first is the total. b Including twelve plants (all late mutants) with which determination of the form of flower was impossible. [107] 250 MISCELLANEOUS STUDIES and 6, in the order there given, except that the arrangement by inter- nodes reverses the two-day difference in earliness of the parents of lots 19 and 20; for convenient comparison, the parental and parent- lot internode values are included in table 19. Two progeny lots were set in each of the fourteen rows; probably the soil was less favorable at the east end of the plot, and hence for the even-numbered lots, at least in about the last seven rows out of the fourteen. The plants were beginning to grow very rapidly when moved to the field. On account of deficient soil moisture and excessive heat, the transplanting was slow and in part purposely delayed, covering a period of five days. Lots 21 to 28 were set three days later than lots 80 3 70 I 60 k 50 Si 40 g 30 V * 20 10 ODD — — "---• . ._... ..... -— 1 2 3 4 5 6 7 8 9 10 11 12 13 14 (C) (C) (C) (C) Row number Chart 2. 1911, field; lots transplanted from greenhouse. Percentages of progeny lots not flowering by November 3, for singles. Apparent mutants and injured plants eliminated. Odd-numbered lots represented by solid line. (C) indicate check rows. The curves are broken between rows 10 and 11, where a cultural difference enters. 11 to 20, and the later loss of roots resulting seems, in spite of rain coming the next day, to have seriously delayed flowering. Lots 1 and 2 wilted badly after transplanting, and some difference in soil con- ditions in the flats, rather than a genetic difference, was doubtless responsible for the exceptional lateness of these lots. Lot 20 lost an exceptionally large leaf area as a result of transplanting. A fungus disease (a slow stem rot) was more common on lots 20 to 24 than elsewhere; it doubtless killed some young plants and delayed or pre- vented flowering in some other cases. Possibly the soil was poorer in the later rows. [108] MUTATION IN MATTE 10 LA 251 TABLE 15 1911, -field; plants transplanted from greenhouse. Plants alive November 3, not having flowered. Singles. Row Lot Non- flowering plants Non-flowering, Snowflake and early types* Lot Non-flowering plants Non-flowering, Snowflake and early types8 1 1 27 26 2 29 28 (27) 2 3 5 2 4 7 5 3 5 9 9 6 11 11 4 7 7 5 8 17 17 5 9 0 0 10 2 2(1) 6 11 1 0 12 9 7 7 13 19 18(17) 14 20 19 8 15 12 12 16 14 14 9 17 1 1 18 8(7?) 7(6?) 10 19 0 0 20 3 3 11 21 8 8 22" 11 10 12 23 21 20 24 23 23 13 25 16 14(12) 26 14 12 14 27 23 22 28 24 24 a Omitting non-flowering apparent mutants. For the numbers in parenthesis, "doubtful mutants" are classed as mutants. Two plants accidentally seriously injured, in lots 14 and 25, were counted out with the mutants. " The stem-rot disease (see p. 108) was evidently worst in lot 22; some two or three of the worst infected plants (included above) were nearly or quite dead by November 3. TABLE 16 Same as table 15, for doubles. Row Lot Non- flowering plants Non-flowering, Snowflake and early types* Lot Non-flowering plants Non-flowering, Snowflake and early types* 1 1 4 2 2 0 0 2 3 3 1 4 1 1(0) 3 5 3 3 6 0 0 4 7 3 2(1) 8 3 1 5 9 2 0 10 0 0 6 11 0 0 12 0 0 7 13 4 2(1) 14 1 1 8 15 2 2 16 6 5 9 17 1 0 18 3 3(2) 10 19 0 0 20 2 2 11 21 3 1 22 1 1 12 23 5 5 24 4 4 13 25 1 1 26 7 5 14 27 1 1 28 10 8 a See notes to table 15. [109] 252 MISCELLANEOUS STUDIES Altogether, these cultures are doubtless much less reliable for their size than the greenhouse tests of the early type, but they nevertheless, with due consideration of the points just mentioned, seem to permit of fairly safe conclusions for most of the parents. The plants were examined for flowering every other afternoon from July 4 to November 3, inclusive (73 to 195 days from sowing) . A very large part of the plants flowered in July, some in August, and a few still later. Evidently the high summer temperature largely inhibited flowering ; many of the singles and a few of the doubles entirely failed to flower. 100 00 so 70 50 40 30 10 Chart 3. 1911, field; lots transplanted from greenhouse. Percentages of progeny lots with primary cluster flowering or aborted by October 10-16, for singles. Lines as in chart 2. Figures 5 and 6 show the plants in July. Growth was usually vigorous through the season, but the internodes were very short, the branches numerous, and the region of the terminal inflorescence often abortive, so that determination of the number of main-stem internodes was not practicable. The emergence of the earliest corolla on the plant was recorded at the bi-diurnal observations, and at two periods during the season the aborted primary clusters were noted. The data show very definitely the transmission of "earliness" by the fewer-noded progeny of WG9-C10. Tables 15 and 16 show the numbers of plants alive, without having flowered, on November 3 ; the figures are thus a measure of lateness. The two progeny lots in each row are given one line in each of the tables, in order to facilitate separate comparison of the fourteen lots in each end half of the plot. £V£ V ODD 1 (C) L™. 2 3 4 5 6 7 8 9 10 11 12 13 14 (C) (C) (C) Row number [110] MU1ATION IN MATTHIOLA 253 The last column, with the apparent mutants omitted, no doubt gives the best comparison. The data for the singles, reduced to percentages, are also given in chart 2. The doubles, which are often earlier to flower than the singles under unfavorable climatic conditions, flowered so generally that table 16 presents no significant differences. The singles (table 15), however, give definite evidence of segregation ; the lots in rows 2, 5, 6, and 9 to 11 all show a tendency to early flowering. Lot 26, consisting of Fa TABLE 17 1911, -field; plants transplanted from greenhouse. Singles with primary inflorescence flowering or aborted as indicated.* Row Lot Aborted by July 29 Flowering or aborted by Oct. 10-16 Lot Aborted by July 29 Flowering or aborted by Oct. 10-16 1 1 0 0 2 0 0(2) 2 3 12 (13) 19 (22) 4 20 24 (26) 3 5 2 2 6 4 8(9) 4 7 2(3) 3(4) 8 1 1(2) 5 9 22 27 10 26 33 6 11 25 29 (30) 12 17 22 7 13 1 2(4) 14 2(3) 2(3) 8 15 4 5(6) 16 0(1) 1(2) 9 17 19 (20) 20 (23) 18 9 12 10 19 25 (27) 29 (31) 20 11 12 11 21 4 6(8) 22 7 9 12 23 2 3(4) 24 1 1(2) 13 25 0 3(4) 26 3 4(5) 14 27 1 3(4) 28 0 0(1) a In this table and also in table 18 the numbers in parenthesis include the probable but somewhat doubtful cases. progeny of "WG9-C10, is decidedly earlier than the adjacent lots. Lot 25 also appears early, however. Tables 17 and 18 give a direct measure of earliness, relating to the primary inflorescence alone. The clusters visibly aborted were in general relatively far advanced, and those aborted at the earlier date correspond to decidedly early flowering; consequently the flowering and aborted clusters are classed together as early. Chart 3 gives the percentages for singles. Here the data for the doubles show fairly consistent differences in the number aborted at the earlier date, while the October totals are [in] 254 MISCELLANEOUS STUDIES less regular. There are contrasts similar to those of table 15 up to lot 26, which is late, while the check lots 27 and 28 are early. The singles show the type differences very strikingly throughout lots 1 to 20, while lots 21, 22, and 26 give less positive indications of the presence of the early factor. Table 19 gives the numbers of singles flowering, in primary in- florescence or elsewhere, by November 3, when growth had practically stopped. The indications are in general the same as with the data already discussed, with better evidence than usual that lots 21 and 22 TABLE 18 Same as table 17, for doubles.* Row Lot Aborted by July 29 Flowering or aborted by Oct. 10-16 Lot Aborted by July 29 Flowering or aborted by Oct. 10-16 1 1 15 30 2 6 22 (23) 2 3 23 33 (34) 4 21 35 3 5 12 29 (30) 6 16 30 (31) 4 7 17 30 8 8 22 (24) 5 9 25 41 10 24 41 6 11 25 (26) 40 (41) 12 23 40 7 13 16 28 14 22 31 8 15 27 37 (39) 16 11 (12) 29 (32) 9 17 20 35 18 20 (21) 32 (33) 10 19 21 41 (42) 20 21 42(44) 11 21 22 35 22 18 27 (28) 12 23 16 (17) 27 (28) 24 10 16(17) 13 25 17 25 26 9 15 14 27 21 29 (30) 28 20 25 (27) * See note to table 17. possessed the early factor. The mean time of flowering is irregular, but shows some effect of the earliness factor. Lot 26 is late as to number flowering, but early as to mean. Table 20, for doubles flowering by August 1, no doubt gives more reliable means; these means disagree with our scheme only in lot 26 and perhaps lot 22. According to tables 17-20, the fewer-noded check parent of each check row has usually given the earlier progeny. In fact, the agree- ment of parental and progeny differences, throughout the cultures, is decidedly remarkable. It is unfortunate that the later parents were always placed in the east half of the row, especially in view of the fact that there was indication of important differences in soil and [112] MUTATION IN MATTHIOLA 255 TABLE 19 1911, field; plants transplanted from greenhouse. Time from sowing to emergence of earliest corolla. Singles. Row Parent-lot internode mean Lot Parental internode number Progeny flowering by Nov. 3 Lot Parental internode number Progeny flowering by Nov. 3 Number Days to flowering Number Days to flowering 1 29.60 1 29 7 147.14 2 32 7 128.57 2 21.40 3 16 34 91.94 4 20 33 105.45 3 5 25 26 119.46 • 6 27 25 104.08 4 49.57 7 46 30 103.13 8 54 24 105.67 5 9 21 30 91.73 10 21 34 91.12 6 27.33 11 22 33 98.85 12 25 27 108.30 7 13 34 18 100.67 14 41 13 120.62 8 28.50 15 27 17 112.94 16 29 18 118.00 9 17 33 30 100.27 18 35. 18 109.67 10 19 36 34 97.35 20 37 21 117.81 11 42.56a 21 42 25 129.36 22 45 25 121.76 12 23 49 11 122 . 00 24 51 14 151.57 13 25 55 15 136.40 26 13 121.08 14 47.80 27 46 10 159.40 28 56 8 162.50 a This parent-lot value does not applv to lot 26, which consists of progeny of WG9-C10 itself. TABLE 20 Same as table 19, -for doubles flowering by August 1. Row Lot Progeny flowering by Aug. la Lot Progeny flowering by Aug. 1 Number Days to flowering Number Days to flowering 1 1 38 90.26 2 33 91.03 2 3 36 80.22 4 36 80.00 3 5 39 84.46 6 39 84.10 4 7 36 81.28 8 31 84.32 5 9 42 75.86 10 41 76.59 6 11 42 77.90 12 40 80.25 7 13 37 84.32 14 35 84.80 8 15 46 83.87 16 33 85.21 9 17 37 80.43 18 34 84.12 10 19 42 78.24 20 39 83.85 11 21 39 85.95 22 30 87.93 12 23 33 89.03 24 26 88.85 13 25 32 88.56 26 21 89.05 14 27 35 88.97 28 29 90.28 a Only 48 more doubles altogether flowered by November 3, and 25 of these were in the even-numbered lots 20 to 28. 256 MISCELLANEOUS STUDIES probably in the incidence of disease, favoring the plants in the west half. The internode data of 1910, however, show a similar tendency. Small genetic differences are suggested, though it would be remarkable if they were so uniformly present in these plants of a single line of a usually selfed species, descendants of parents and a common grand- parent grown under glass. If such differences exist in the race, conceivably some combination due to crossing might simulate an early mutation. The evidence as a whole, however, does not favor such an origin for our early type ; it is widely divergent from the Snowflake type, and seems to depend on a single main factor difference from Snowflake. TABLE 21 Cultures of 1912. Ancestry and parental data. Parental data Lot Parent Probable type Days to Inter- Seeds sown flowering <* nodes'1 1 WS1-W216 Snowflake8 120.5 38 15 2 WG9-C10-W6 Early 116.5 33 15 3 WL10-W>2 Snowflake 139.5 51 15 4 WL10-W23 Snowflake" 120.5 38 15 5 WS1-W21 Snowflake 141.5 57 15 6 WL10-W214 Snowflake" 126.5 38 15 7 WL10-W27 Snowflake 145.5 54 15 8 WG9-C10-W8 Early 129.5 45 15 9 WS1-W212 Crenate-leaved3-1' 119.5 34 7c * Suspected before testing of belonging to the early type; first parent also tested in 1910. b A heterozygote between the crenate-leaved and Snowflake types. c Probably open pollinated. d All the parents grew in the same house at the same time. The essential feature of the supplementary cultures of 1912. since no seed of WL10 remained, was a test of two pairs of early and late progeny of "WL10 (lots 3 and 4, 6 and 7, table 21), in comparison with two control lots — one (lot 2) from a known early parent, descended from WG9-C10, and one (lot 5) from a late descendent of WS1. Incidentally, WS1-W216 and WG9-C10-W8 were retested, and the few available seeds of WS1-W,12 were used to test that phenotypically early parent. The results are given in tables 22 and 23 and chart 4. The very low individual from WS1-W216 came from a very weak embryo, and should be disregarded; the exceptionally high general range of this lot, which was also visibly behind all others in development, was prob- L114] 257 TABLE 22 Cultures of 1912. Number of main-stem internodes 'below first flower-bearing node. Frequency distributions for singles.* 1 Gen. 1 WSl WG9 WL10 WSl WL10 WG9 WSl Ancestry •< Gen. 2 W216 CIO W22 W23 W21 W214 W27 CIO W212 [ Gen. 3 W6 W8 Internodes 18 It 19 1 20 1 21 22 1 3 23 24 2 25 26 It i i 4 1 1 i 1 3 3 1 27 2 1 2 1 28 .. 3 2 1 U It 29 1 2 1 30 31 32 33 34 35 2t * See note a to table 5. TABLE 23 Cultures of 191S. Same as table 22, for doubles." [ Gen. 1 WSl WG9 WL10 WSl WL10 WG9 WSl Ancestry -i Gen. 2 W216 CIO W22 W23 W21 W2 14 W27 CIO W212 1 Gen. 3 we W8 Internodes 12 1A 13 14 15 16 17 1 18 1 1 1 2 2 1 19 20 1 21 1 1 1 1 2 3 2 2 i" 2 i" i 22 1 23 i 5 1 It 3 3 2 2" 3 i" 3 1 24 25 .. 26 27 2 3t 28 it 29 30 1 31 1 a See note a to table 5. [115] 258 MISCELLANEOUS STUDIES ably due tu some cultural accident, perhaps to an excess of moisture in this row of pots. The lots of plants may seem rather absurdly small for their pur- pose, but the uniformity of development here, with the marked normal divergence in internodes of the types in question, seems to justify a fair degree of confidence. Ten plants here were probably worth fifty in the field. 31 30 2<) 28 27 20 2,5 21 23 22 21 20 19 IS 17 If. c, r ingl oubl 68 68 - - 1 1 — .__ _ — - .__ i 1 • — . — 1 — < ^ •~~" ~— ~ < i W,16 W6 WS1 CIO W22 W23 i i Wil 1 WS1 W,14 W,7 i W8 Wil2 CIO WS1 wiio wi,io WG9 Ancestry WG9 Chart 4. Cultures of 1912. Internodes: parental values and progeny means, shown as in chart 1. The true parental values are twice those indicated by the ordinate figures, which apply directly to the progeny values. This test, with that of 1910, shows very positively that WS1-W216 was only phenotypically few-noded. Evidently WG9-C10-W8, the parent of field lot 22, really carried the earliness factor, as was some- what doubtfully inferred from the field results; the five progeny of WS1-W212, on the other hand, though from a fewer-noded parent, have values that make the presence of the earliness factor improbable. On the main point at issue the evidence seems satisfactory. Neither of the two very early and few-noded progeny of WLIO represented [116] MUTATION IN MATTHIOLA 259 shows in its progeny any evidence of belonging to the early type ; the means are slightly lower than for the many-noded sibs of these parents, but far less so than with the parents descended from WG9-C10. We conclude, then, that WG9-C10 was probably a monohybrid, and that the early-bearing gamete entering into its composition was of unknown but presumably mutative origin. Most of the extracted late or many-noded parents may now be selected with practical certainty. "WG9-C10-C8 and Cl (lots 5 and 6 in the 1911F cultures) and WG9-C10-M7 and M8 (lots 13 and 14) were genetically very similar to the check parents, as has already been concluded for two of them from the greenhouse cultures ; presumably they were pure Snowflake. The data for WG9-C10 itself (lot 26) seem to indicate that the results from the last eight lots are of very doubtful value ; still, they show, especially in the original individual records, some evidence of the earliness factor which must be present in part of the individuals. The poor and slow germination of the old seed available may have had an important influence on the result ; many of the early embryos may have been non-viable, and the seedlings may have been weaker than those from fresh seed. The 1911 data and observation of the plants in the field suggest that WG9-C10-W7, W3, and W10 (lots 23, 24, and 25) are the only remaining extracted late parents, WG9-C10-W5 and W8 (lots 21 and 22) carrying the earliness factor, as the four parents just preceding them in the cultures obviously did. Tables 22 and 23 con- firm this conclusion for WG9-C10-W8. It is presumably impossible to make a positive separation of the parents homozygous for the presence of the early factor. The green- house data suggest that WG9-C10-M4 was a pure early individual; the field data (see lot 9) agree, and suggest that WG9-C10-M9 (lot 10) and perhaps WG9-C10-M6 (lot 11) belong in the same class. WG9-C10-C2, C5, and CIO (lots 3, 4, and 40) 12 were all evidently heterozygous. Of the parents grown in house W, it would seem that only WG9-C10-W11 (field lot 19) was homozygous early. We have, provisionally, for the available single progeny of WG9-C10: House 0 House M House W Total Pure early 0314 Hybrid early 3159 Pure late 2237 20 12 Statistical data given for the last only for the 1910 cultures, not for this field lot. [1171 260 MISCELLANEOUS STUDIES This corresponds well enough with the monohybrid expectation of 5 : 10 : 5 ; in fact, the deviation is just such as would be expected if there was occasional cross pollination of the unprotected flowers of WG9- C10 from Snowflake plants. The large proportion of evidently pure late parents is strong evidence for the monohybrid nature of "WG9-C10. The proportions of the two types among the doubles can only be estimated. The 1908 data suggest that 5 of the 10 doubles there reported were early ; this number, with the 13 singles so classed, makes a total of 18 early-type plants out of 30. The ratio is slightly nearer to 1 : 1 than to 3:1, and the former proportion would suggest the peculiar type of inheritance found with the mutant types yet to be described. The evidence of the 1910 distributions, however, shows that the early type largely predominates in the next generation with both singles and doubles, and apparently this is true even when we exclude the progeny of the one parent classed as pure early. The early factor can be positively detected only by progeny tests. No test has shown the presence of this factor elsewhere than in WG9- C10 and part of its descendants. WG9-C10 produced the early and Snowflake types among 20 single progeny nearly in the typical mono- hybrid proportions: Inspection of the double progeny in two genera- tions suggests similar or possibly somewhat lower proportions there. A vicinistic origin for WG9-C10 is improbable. Presumably, then, the early type arose from Snowflake by a single factor mutation, the dominant mutant factor being inherited without special complications. We shall now consider certain apparently mutant types which are characterized by peculiar genetic behavior. 2. THE SMOOTH-LEAVED TYPE This type was first observed in the cultures of 1908 (table 1) and has occurred frequently in later cultures (table 3). It is perhaps the mutant type of most frequent occurrence among progeny of Snow- flake or early parents; 2410 unselected progeny from house-sown seed of such parents (see table 28) included 28 apparent mutants (14 singles, 11 doubles, and 3 undetermined), a mutation coefficient of 1.16 ± .15 per cent. As grown in the greenhouse at Ithaca, this type (fig. 7, tables 12 and 13) was often many-noded, with correspondingly late flowering. Its most striking peculiarity, shown especially by young seedlings and not evident in the figures, was a lack of buckling between the veins [118] MUTATION IN MATTE 10 LA 261 ri «"*" 03 * ^ » g«i ' g & , on; * s °1S. °' « o O M, 5-2 00 CD sJ!>tototototO2:>co;> w to to £ J> w to to Kt-osososascsgc-gc-. as cs GS g £-• as 35 as 9 —o 5 o o o-§ —g — o 7 erg — « crp 1 ^icJocoJ,t IS co 4X1^ g. ^J^ P- Er oy fD in Parents ^ CO CO O CO CO — ^ CO CO CO CO CO !— CO CO CO CO CO Q »-> CO CO 00 h- CO h-> CO i-> (-1 i-» O *-> O I-* K W ^ W^ K W ^ gc ^ o, ^ to" to" H- ' h- ' *. ){X 1 1 tO Oi ts5 I-1 >— to >~* O tOlOCDCntOO Oi h- H-" tO^ ^ v} ^ CO O W^cn O O O O5 00 CX) O^ JO vO Co Oi tf» ^ ££> i~* O C) >— • "-» Cr^ •^ -^ 8? • L Cr to ootooooo o» co to oco oj o o Undeter- mined H o ? n I—1 tO I— ' h-> M to tO M £- i— CO h-> Oi Cn H- ts3 tO O> CO O O 00 >— ' CO *»• CO Cn OS CO O» H- > CO Oi Deter- mined 4^ to : B tr i (B IB <; 9 PL, 1 OS CO !-• h-> 00 h- O OOOOOCO h- ' ?D t— ' H- 'tO 00 O5 OO as "co 'to ^ i5 -S > 2 P" 9 e 00 l—COtO 4*. CO h- IO I-" -~J (-- CO rfi. Oi tO *«• tO O tO 00 bO O : '00 "OO^'oo'tO ^ 'CO "h^ T3 -S "^^B^-S S c3 w M SP 5' N_ !T O^IOOOOh-'^l «5 O> CO h^-00 CO Oi : 00 'H^'Pc;? ">£ 'H- 'to CO Cn CO O tO 00 O H o 2 Snowfla 0 I— ' h- ' O5 h-> h-Kl CO H-> Oi M tO tf»- ^1 >-« tO 4> I-* 00 00 H- M ^J h-i 4^ OO O Oi • t-> H- « 1— ' -^j'4». H- ' 1— ' 00 CO rfk OOI-« 4^ O3 CO CO tO O CO OS O H- CO >-" CO OS > ^- ^ CO h- ' H-> t-> O 4^- CO I—1 tO I— ' O I— 4^ r-> CO--iO TfOOOOO O O P to a S3-Sd-2- ^ -H 3" ^ *~I.§S d-§- rt "*• «C O CO ••# 00 i-H «C Tj< CO 00 OC »C t^ O t> CO -Ht^Ttt-^OJ-^ O »C C^J i-H -HO CN »C 1-1 i-l •-! c. M 0) ^ _ _ _ 1 i 3 Q OS S S SS §S £ : Q - 13 =, J ~. 9 a e '-™^ x— v P fl> x — xx-*«, x — ^ x-*\^"*s.-- — s-— -^ ^^ Is1* r 0 li = SSG- G SSS-SG- 2!- t _^ ^ £ COOC<>i-Hr^-H-HC<|iMCO-HiC»Ci-l- oc o -H t>- ooo-Hcoci'f t^ »c be «J '§ 11 (N CO r: ^> m •s. £_ c" $•0 ^ 8 o 1.1 00 ^J O> ^4 Tf^ ^J ^} ^J C^ C*~J ^^ ^^* ^? ^3 *^» Q$ Ci C^ ^^ C^ i-l " W (N rf EO CO -^ Tt^CO i-( 1-4 OS I CO CO CO CO CO CO CO CO CO CO CO CO CO O CO CO CO CO 71 | """' ^''lAJi'i^'JiJi11 ''''i ' ~. O OS^OJOSOJOSOCJOSO: OSOSCSSSCSOSC:^: CiOCSClCS — 0 O 39 V OOC 00 J. COCOiMC^^g3,- ^ o a % i— IOOOSOJCO''t<^fiC»C'CCOJOCOt>-f>-Cs4 OOOOOSCsfeS"*^ t^1^ llllllllliT Till jiiii^g- i cc <0 T" O5c3c3c3c3c3o3c3^^3^3rf^c3c3c? rtc5rfc3o3 \ > — c3 ^ 00 n CM * c5SSc^c^SSc5c^c5c5c5c^c5c5c5 cSc3cS?i?5'r>s MISCELLANEOUS STUDIES narrow ; under unfavorable weather conditions the flowers are often few and defective, while the leaves are resistant and long-lived (fig. 11). Figures 12 and 13 show well the coarse leaves and lateness of well developed large-leaved plants in the 1915-16 cult'ures, the plants in the latter figure being several weeks the older. The results of the progeny tests are given in tables 26 and 27. All the twenty large-leaved individuals tested have given mixed progeny; the proportion of the mutant type, though much larger than with TABLE 27 Large-leaved type: heredity. Summary. Progeny Plants Parents Cultures Seeds" Total examined Large-leaved Undeter- mined Deter- mined Number Per cent 28a 1913, 1914, & 1915-16 122 2 73 38(40) 54.8 * 3.9 28a-F, (3) 1914 120 2 40 14 (19) 47.5 * 5.3 28a-F, (12) 1915-16 288 2 190 76 (90) 47.4 ± 2.4 28a-F2 (4) 1915-16 90 0 54 25 (26) 48.1 =*= 4.6 28a-F, & F2 (19) All 498 4 284 115 (135) 47.5 * 2.0 All large-leaved (20) All 620 6 357 153 (175) 49.0 * 1.8 Large-leaved Germination good 360 3 260b 115(131) 50.4 * 2.1 Large-leaved Germination poor 260 3 97b 38(44) 45.4 ± 3.4 Snowflake (1, F,) 1915-16 24 0 15 0 0 • Mainly from unguarded flowers; see table 26. b Eespectively 72.2 and 37.3 per cent of the numbers of seeds planted. smooth-leaved, approximates to 50 per cent, not 75 per cent, with little indication of selective elimination with poor germination.10 Here plainly, as with smooth-leaved, no pure mutant-type parent has yet been tested. Since this is also true of the other types, aside from early, that have been somewhat extensively tested, and fifty-three mutant-type parents in all have given Snowflake progeny, it is prob- able that homozygous individuals of these types seldom or never develop. The actual adult ratio with large-leaved is plainly not 2 : 1. but rather 1 : 1, a fact that would suggest absence of the mutant-type factor or factors from the pollen. The small trial cultures started in 1917, however, show that the type is carried by both sperm and eggs. is Since hybrids are of the mutant type in appearance, the possible cross pollination by Snowflake parents could hardly give Snowflake progeny with any pure large-leaved parent. It may, however, have reduced slightly the proportion of large-leaved progeny from heterozygous parents of this type. [1261 MUTATION IN MATTE 10 LA 269 If we are dealing here with a type cytologically like Oenothera gigas, or rather the triploid semigigas, abnormal distributions of chromosomes may occur at meiosis, giving unpredictable genetic results. There has been special difficulty, as the numbers of doubtful individuals in table 26 suggest, in separating large-leaved from Snow- flake, though in part of the cases the difference is extreme. Possibly some of the doubtful individuals are genetic intermediates due to irregular meiosis in triploid nuclei; such irregularities in division (Gates, 1915) occur with Oenothera. Both cytological examination and crosses with Snowflake are plainly required. TABLE 28 Crenate-leaved type: numbers of apparent mutants and association of the type with singleness of flowers. Culture Progeny of Snowflake and early parents Total examined8 Crenate-leaved Single Double All Coefficient of mutation 1908 1910 191 IF, seed house- sown All above All unselected 725b 338 2072 3135 2410 6 3 13 22 16 1 0 3 4 3 7 3 16 26 19 .97 =»= .22 .89 ± .32 .77 * .13 .83 ± .11 .79 ± .12 a See note b to table 2. b See note c to table 1. 4. THE CRENATE-LEAVED TYPE This type (tables 1 and 3) is one of the three aberrant types of most frequent occurrence in the cultures here described, having con- stituted (table 28) about .79 per cent of the progeny of Snowflake and early parents. A large majority of the individuals have been singles, as table 28 shows. If the apparent mutants are produced by some process of segregation of factors, evidently the crenate and single factors were usually coupled in this material; if they are produced by immediate factor mutation, or are individually due to some change in a particular locus, evidently that locus is linked with the single- double locus and the change is more frequent in the single-carrying chromosomes; and finally, if they are due to reduplication or loss of a chromosome, the apparent linkage remains to be explained. The margins of Snowflake leaves vary from entire or slightly sinuate to coarsely and irregularly dentate or serrate, this character- istic being subject to much environmental modification and varying [1271 270 MISCELLANEOUS STUDIES i < " 00 > £ C<1 CO CoS" CD" C1! j : - S»^ -^.X S^.XS^^ N^^ V ^ j >« «— ' O O »— i Ol >— iC^I^HC^ CflO ^f CO >C = G.S2- £3 d- £i ** i2. & < O5OC- »-i O 00 Cli-HC^CSO-HO >C C^ OC — O4 04 CO ~. — CO ~~ ~~ ~~ CO • ~ ""• (N 0 ^^ M O •*-"•«. >^^», *i^*v /^*s C^ | 1 3 g § 5- S S d c c Q 1— ( . ^s "g1 •C t>- C^I CO bo o -^ o d co i— i *c co c^ c co ic oo oo »c CO jj --v 00 | a ^~, ^-v^~. Id — I * **< ** O5 •* O5 CO 00 CO »C 1C 1C ^ O5 CO OO CO (N CO •«* IM a o M I — s-~* Tf 1C O IB 2 0 3 3 m B B O Q O M O »-< CO c^FHC-H Tf CO I-H N*~i t>-iCNC^CO5CS ^ 03 Q> G) | - c ^^ 2ooos2 S - c -— •" 1 1 t | 1 r^H •* C«i — /*• ^ ^Q _ u c3 — • • • ^3 13 'rt Tj C^ C^ C^ ^^ ^ IN C^l !N (N C^ C^ C1 CD CO OJ I-H 00 O3 CM i-l CO OO OS i-l i-l co • ^ jrf eS jj ^* ao ,~, e* XV S -^^ 0 a C5 o t» i— i T-I CD 10 o; ic i— i co •* GC oi o s-^ IS iO »^ CO a S ^N. ' V»^ oo T^CC^COO»— I^H ^ ^O *O ^C rH 1C -2 0 I £ ^< - — - O"*r-iOOOO «3 -^OO O i-H rH • • o ,— 1 3 £ I • C g Q : : : : CO ^ ' ' ' ' iC(NcO:::: 1-1 01:: : Tt* g c "3> »C (N rt< : : : : I-H "5 : - : : c T-I : : : : CM CM : : : 02 : : : : i— i : : : 1 C i II t>» t"* 00 i-H CM t** CO 00 CO ^f OS CO CO rH »C (N CO rH CM i M * • jg-C 3 O ' II i-HOCOOOOO •* CO O O O H 5s i-H 00 •8 ..^f • i a •* 0»C S 3 i— I i-H i— Ir— ( r— 1 i— ( i— < _ _, i— IT— 1 _- 0 O5OO5O5O5O5O5 ^J33JJ O5O5 ^Jj OOi^CNCOCOOS 5"cS i^* H 0 |CM*O«5iC>C'C rtS OS OC*1! i PH 0 -O "O T3 "O "O T3 ^^ O.-3 ^bt3j-.^ c « 272 MISCELLANEOUS STUDIES with the position of the leaves on the plant. In the crenate-leaved type this character is much accentuated, as can be seen by comparing figure 14 with figures 1 and 3 ; a warm greenhouse (fig. 14, upper line) gave very marked serration, while a cool greenhouse (lower plant, and also fig. 15) produced leaves much more nearly entire. Under the much more extreme conditions of insolation, temperature, and humidity at Riverside, this type was often much dwarfed in com- parison with Snowflake (figs. 16 and 17; see also fig. 23). In general, growth is weaker than with Snowflake and the stems more slender. Buds and flowers are often produced in great abundance, but the capsules are relatively few, small, and few-seeded. See tables 12 and 13 for internode data. The progeny tests (table 29) show a slightly higher proportion of mutant-type progeny than occurred with smooth-leaved. A striking new feature appears for the first time in these results, the regular presence of linkage, or an association simulating linkage, with the single-double allelomorphs. Further, in all the four apparent mutants tested the crenate factor seems to be coupled with singleness, while among the sixteen F1 and F2 crenate parents there seem to be no crossovers.17 We seem to be justified, for reasons just given, in summing the progeny as in the tables. Two things appear at once in table 29 : ( 1 ) there is a great excess of total doubles over the usual 53 per cent; (2) there is a much greater excess of doubles with Snow- flake than of singles with crenate; (3) the supposed double-recessive class (Snowflake double) is about two and one-half times as large as the double-dominant class (crenate single). Table 30 adds two features of special interest. First, there is good evidence of selective elimination with poor germination ; compare the remaining percentages with those for "Ithaca, field," "1915," "P1?" and "Germination poor," and see tables 39 and 40; the only excep- tional case is the low percentage for the thirty plants of 1915-16. It would be surprising if the slow and weak growth of the crenate plants did not lead to such a result. Second, there is evidence that the crenate individuals are smaller than Snowflake even before germina- tion. The seeds of crenate parents are less uniform in size than those of Snowflake parents; small seeds are numerous, and even the larger ones probably weigh decidedly less than normal Snowflake seeds. With five crenate parents included in the cultures of 1913, random 17 With four of the parents the tests are obviously entirely inadequate; one other, 22d-9, gives no indication of linkage among nineteen progeny. [1301 MUTATION IN MATTHIOLA 273 • CD O O JO J£) p3 •CJ TO O O GO <-» PL, tO H- CD Oo Qo Ol h-i CO h-» Oi *>• (-"vlCOtOtOOOtO h-O5 H-'WtOWl-'tOCOh-'l-'OOtOH-'OO H-H-H-H-H-H-H-H-H-H-H-H-H- [131] 274 MISCELLANEOUS STUDIES samples of seed were sorted, and the smaller and larger seeds planted separately. Table 31 gives the data from this test. Here is practically con- clusive evidence (see tables 39 and 40) that the smaller seeds much more often contain embryos of the crenate type.18 Since the embryo of a Matthiola seed occupies practically all the space within the seed coats, it is evident that even as embryos Snowflake plants exceed TABLE 31 Cultures of 1913. Crenate-leaved type: proportions from smaller and larger seeds of crenate parents. Seeds Progeny p t Total /"• 1 A Size Number deter- mined vy rena te- lea veci Snowflake Other types Number Per cent 22a-l Smaller 21 6 4(5) 83.3 ± 12.9 0 1 22a-l Larger 29 23 3 13.0 * 6.6 19 (20) 0 22a-5 Smaller 17 11 4 36.4 ± 9.5 6 1 22a-5 Larger 33 28 2 7.1 =»= 6.0 25 1 22b Smaller 13 8 5 62.5 * 11.2 3 0 22b Larger 36 31 4 12.9 =*= 5.7 25 (27) 0 22d-12 Smaller 30 24 17 70.8 =*= 6.5 5 2 22d-12 Larger 70 57 11(12) 21.1 ± 4.2 42 (44) 1 22d-15 Smaller 32 24 17 70.8 =»= 6.5 3 2(4) 22d-15 Larger 68 54 18 33.3 ± 4.3 34 (35) 1 All Smaller 113 73" 47 (48) 65.8 ± 3.7 17 6(8) All Larger 236 193a 38 (39) 20.2 ± 2.3 145 (151) 3 All All 349 266 85 (87) 32.7 ± 1.9 162 (168) 9(11) • Respectively 64.6 and 81.8 per cent of the numbers of seeds planted. crenate plants in size. This fact, obviously, is further evidence in favor of the hypothesis of partial selective elimination of crenate heterozygotes during embryonic development. It may be worth noting that the 73 plants from the smaller seeds include 6 (8) apparent mutants of other types (mutation coefficient 11.0 per cent), while the 193 plants from the larger seeds include only 3 apparent mutants (1.6 per cent). Before we can profitably discuss these data further, we must con- sider the results from cross pollination (tables 32 and 33). The numbers, though small, make it very probable that both eggs and sperms carry the crenate factor. Further, it appears from series 20 that only a small portion of the sperms carry this factor, as we should expect from its apparent linkage with singleness. If homozygotes are non- viable, the combined crenate percentages of reciprocal crosses should 18 The poorer germination of the smaller seeds suggests that the disparity between the two lots of seeds in the proportion of crenate embryos was even greater than the cultures indicate. [132] MUTATION IN MATTHIOLA 275 03 02 a » o » o; p, Jf sr*o co ;> to to to j> tr1 to to to to to K»TJ to to to rv^ O tO •"" {i- CT" P tO *— * as £TTO CR !3J Q- ?? ' G* 3 f ;T P "i 2 i >— ' o PJ tj^ P o o '-'• p.fM "*> CD o 5.4. CT^ cr P V !fl 1 if *f I r Cn "* n a>- 5^° ft) - — So Se 01 to o . - co o co E— • co co co co co co co co co co co 0 — . - Cn rf* co Cn Cn Cn Cn Cn cn rf* cocococo -^ So I CJi OS Cv C^ * 3$ CT- 1 M M <> CO CO O tO tO H-i h- Cn H- ' O5 tO rf».i-»i— ' co osto S'«- 5' Cn OSh-vjOO COCC^tOCn^H^ ^COrf S-7 n a. to : : tOOO COt-'i-'Oi-'O'. Cn: rfi.i-' 00 •S i i i i a' O O : : OCO CO O O H* O tO : : O O Drenat o "2 ' ' — " ' ' — " § 7. S *--^ ^—s '. *^*s cr Q a 5" » "< 1 1— 1 IO OOtOt-4 OS i-« h-> h- h- ' ts3 O CnOtt^t-1 , ^ ^.^^ ^^^^^^^ ^-^ , — ^ ^» 3 i-« co co t-j os Cn sr »— 5 Cn •<> rf*. *-• co to co co H-otoj* H- M en en ~j ^1 co Oi-«toyo en H-> to co oo o vi en to >*>• os co co to rf* O DG 5 "ps 1^ 'H^'H^ "en ^ ^ ^ 'Cn "So O | F n x- *-* -3 h- ' l-» H- tO H-> M 00 1— h-i h- CO H- VI Cn tO p— ' to I— '1— ' CO H- ' P— ' rf^ h^ ' 00 CntO tO LO CnCO4^CO)-'tO>^>tOa>tO — CO O OOOO5 tOOOOH- h-O •4XOCOH-' **" C ) ^~^ y^^ x-^\ /*^^ y*^\ *o t 00 CO ^O V\ td M S [133] 276 MISCELLANEOUS STUDIES exceed the percentage from selfed parents; the expected high pro- portion with series 21, however, might well be realized with adequate numbers and good germination. In spite of the small totals, it is very probable that linkage similar to that of the selfed cultures prevails with series 21. Where the crenate type is the pollen parent (series 20) linkage ratios are on our hypothesis impossible, since the eggs are all Snowflake and the sperms all double; the data, however, though statistically inconclusive, sug- gest that the excess of singles with crenate and of doubles with Snow- flake is greatly reduced but not abolished. TABLE 33 hybridization of the Snow flake and crenate-leaved types. Summary. Progeny Plants Parents Cultures Seeds Total examined Crenate Undeter- mined Deter- mined Number Per cent 20aa, bb, & cb 1913 123 5 93 5(6) 6.5 * 1.6 20dc, ed, & ic 1914 163 0 14 0 0 20de,ff,gf,gg,&hd 1915-16 120 0 103 6 5.8 ± 1.5 All of series 20 All 406 5 210 11 (12) 5.7 ± 1.1 21aa, bb, & dd All 75 1 25 2(3) 12.0 * 4.4 Snowflake par- ents of hybrids (5) All 271,50 3 134 (1) .7 * .5 If we may ignore the doubtful correlation just mentioned a fairly adequate complete hypothesis for the selfing ratio is possible. Assume (1) a gametic ratio19 of 5DC :ldC :1Dc :5dc, or 16% per cent of crossing over; (2) non-viability of homozygous crenate (CC) ; (3) low viability of simplex crenate (G'c), eliminating an average of 60 per cent of this type ; and (4) coupling of D and C in all parents tested. Evidence has already been presented for assumptions (1), (2), and (3), except as to the intensity of linkage, while (4), as will be seen, is not at all improbable. Random fertilization under these conditions, excepting (3), would give 26DdCc (crenate single) -(- lOddCc (crenate double) -f- 5Ddcc (Snowflake single) -|- 25ddcc (Snowflake double). The other two classes, 5DdCC and IddCC, would be non-viable pure crenate. Adding assumption (3) gives the following comparison: !» Representing the singleness and doubleness factors by D and d, and the crenate factor and its "normal" allelomorph by C and c. [134] MUTATION IN MATTHIOLA 277 DdCc ddCc Ddcc ddcc Theoretical ratio (n = 44.4) ...... 10.4 4 5 25 Calculated for n = 540 .............. 126 49 61 304 Observed (n = 540)20 .................... 125 51 57 307 This fit surely cannot be criticised, whatever may be thought of the devices employed to obtain it ! With cross pollination the agree- ment is fairly good in the case of series 20, which gives the only fairly reliable data. We are assuming 16% per cent of crossover dC sperms ; elimination of .60 of 16% per cent, or 10 per cent of the total, gives .06%/.90 = 7.4 per cent expected crenate, as against 5.9 per cent observed. Series 21 is supposed to have 50 per cent of C eggs in the ratio 5DC :ldC ; elimination of .60 of this proportion, or 30 per cent of the total, would leave .20/.70 = 28.6 per cent, against 12.0 per cent in the very inadequate material observed. An adequate test of the hypothesis obviously requires large hybrid cultures, from vigorous seed sown under favorable conditions for germination. A scarcity of crossover crenate singles follows from the hypothesis ; they constitute only one twenty-sixth of the total number of viable crenate single progeny of crenate parents. No direct evidence indi- cating that the crenate and double factors are ever coupled in singles has yet been discovered. If the supposed crenate mutants are due to immediate factor muta- tion, however, it seems strange that the same locus is changed more readily in a singleness chromosome than in one carrying the doubleness factor, in a ratio similar to the linkage ratio of later generations. If the apparent mutants are really segregates from a balanced-lethal combination, the observed original coupling of crenate with single might be an accident of sampling involved in the original choice of material; other initial parents might give the reverse coupling. 5. THE SLENDER TYPE This type is comparatively rare as an apparent mutant from Snow- flake or early; the 3135 plants reported in table 28 gave only 4 (6) mutants (2 singles and 4 doubles, 2 of the latter perhaps Snowflake), a mutation coefficient not over .19 per cent. This type seems to occur more frequently among progeny of crenate, a type similar in some 20 Omitting 29 plants classed as neither crenate nor Snowflake, which as probably non-crenate should perhaps be added to Snowflake, and also 64 plants (13 crenate and 51 Snowflake) with flower data incomplete. Complete data for the total of 633 plants would plainly give a somewhat poorer fit, but this could be improved by assuming a slightly greater elimination of Ccii zygotes. [135] 278 MISCELLANEOUS STUDIES 1 I j S 5? cJ "? S" £7 CO" 4 : a *^^f ^ ^^* V s N^^ X_^ c >« OOOi-H T-H O IN O O » ic ^* = CO CO ^ CO i-H i-H "• O OS OS »Cl~- OOT-I t-H Tj< 1C OS *— X \»_^ **_^ o CQ Q ^ OO OO C^ Is* 00 t-H 00 ^* ^t* ^* C^ O5 1C 1C CO T-H 1C IM -* t-H CO t-l 1-H • CO CO ^C 'C c N*^ N ' ^** ^^ in • — — C< O OO C<> O T-H rt< O •*** 1 — , s-^ ^. ^~, ^.^ s-^ ^ 1 3 ~* G- £i £i °° '"'t ^ JS t^ t^ •* TH COO i-HCOOOOS OS O T-H T-H T-H t-H CO T-H CO T-H 1C >. Ui •O 3 s~^ s-^ ic : c5~ «N co co" H 3 1 O X 0 Q O OO OO Tt« T-H t-l : CO T-H C^ h- C<1 1C ^ —, s-.s-^ •a T^T Ct T-H t-H rfl CO c ^ ' ^ V • . ^rf"S» X ^.^ 02 OS OS O O "^t* ' ^f C*3 ^C O CO ^ T-H i-H i-H Tf CO 1 ~ £ i— 1 CO ^f COO r— 1 rH OOb»TfHCO 00 1C OO OO »CiM CO O •* •* CO O I 11 T-H O1 IM a B 1 l! i— I O t-H OO i— i O t— 'OOC^I I-H I-H £ D£ •t I a 05 co" IM~ •*»< o o os co ^ co o~ IN" 06" >•« t^- OS OSCJ t^-CO O^t-iCT-H T— I OS T-H i-H C-eo«o CcOt^-COO | p 1 Q 3 x >, - •o I a V 9 0 £ c h I 1 i— IOi— t i— IOO>— IC^>— 1 r- 1 C »— t i— 1 i-H r— 1 V •d a t> Oo do OQ -^ "^®t SO -^-^- •5 c 2 1C t^ (N (N CO CO OO O (M CO 1C O --H (N 00 de t^» CO »^ 00 CO *C G) i—l GS C3 O5 C5 *— I »•"! Oi i-l N i-i d »C i— I d i— 1 CO i— 1 CO 3 O O O O O | P- I ll "3 °^ CO "^ sj oj O of c3~ of '"H'i» -S-S 000cort*ica3 S6 JJJsSSjSsSS JJJJJJJJ - - «SJJ 2-S X (M [138] MUTATION IN MATTHIOLA 281 probably unlike genetically. In the 1916 cultures, on the other hand, with better development, this type seemed substantially as uniform as the others. If we ignore these possible genetic differences and attempt to apply the scheme worked out for crenate, difficulties appear at once. First, the scarcity of Snownake singles would indicate much closer linkage than with crenate, while the relative abundance of slender doubles apparently contradicts this supposition. Second, the in- adequate results from crossing with Snownake (table 36) suggest that the sperms carry the supposedly crossover slender factor at least as often as do the eggs. While crenate as pollen parent gives results agreeing tolerably with the hypothesis, slender gives results differing from these in the wrong direction. No doubt, however, the disagreements can be over emphasized. Both crenate and slender as seed parent seem to give the expected relations between singles and doubles, and series 23 also does this with the Snownake progeny. Obviously the functional sperms and eggs of these mutant-type parents exhibit different ratios between types, and the peculiar results in other respects with slender may be related to the added complication suggested above. The astonishing feature of the data, of course, is the great excess of single slender over double slender in series 23 — an excess which suggests an actual significant excess of singles in the totals of all types given by this cross — while with selfed slender there is a great total deficiency of singles. We may at least feel confident that the modifications of the single-double ratio, with this type and with crenate, are due to lethal action which also affects the proportions of viable slender and crenate gametes or zygotes. If differential viability before germination is an important factor with these types, very probably it differs according as Snownake or the mutant type is the seed parent, and according to the parental environment. In other words, partial selective elimination during seed formation may vary with the environment of the embryos, accord- ing as this environment is affected by either the genetic constitution or the external environment of the seed parent. Until such uncer- tainties are eliminated, we are hardly justified in ruling out, for the types discussed, the probability that regular segregation and (in the last two cases) true linkage are concerned in these phenomena. In fact, the definite differences in ratios between reciprocal crosses and between at least one of the crosses and selfing encourage further attempts at satisfactory factorial analysis. 282 MISCELLANEOUS STUDIES 05 £2 ^^ ^ •5 M. 21- £. o-» OO O CO iS eojo CM^ c o r/j Q i-< CO Tjl r-( »-l 41 "Kb CCO~ a CO ^ o3 s*^>^*x i-H CD (N O> O »H COCO "3 00 OS 1O CO •* "8 W3 (N CM •* CO "o •H -H -H -ti fl S 4fl a a X 3 S l> CO CO tO ^t| S . k _a •fi it §1 5 ^j c * Iz;"0 CO to CO to CM CM S S CM CM £ IV 3 ^TcM* g s ^v ^ O Q rt i-HO 0 "M CM a CM CM 02 1 1 11 cocoeocM -H t^- CMO3C-1CM CM j— ( c! X 5 , "c3 | 1*2 «J C T-H O O •-* O t-H H 11 PH f •* iooc3sco r- .-H Cl (N 1C tO CD 02 _l ^ CM ^H a • CO CO CO • — ^ T I"1—. "T ** O rH •— ( i— ( S.IS a 2* s — " ^S ® J 3 12 tc 'C « 5 ^a A » +» S «H ® OT G OP -4J [1401 MUTATION IN MATTHIOLA 283 6. THE NAREOW-LEAVED TYPE As table 37 indicates, this type competes with crenate for second place in frequency of occurrence in the Ithaca cultures ; in fact, when only the strictly unselected cultures are considered the percentage is very close to that for smooth-leaved. A feature of special interest is the apparent association of the mutant type with doubleness. In a cool greenhouse this type (fig. 22) varied from exceptionally late and many-noded to ordinary in both characters. The leaves (see also fig. 18) were typically narrow, rather strictly entire, often rolled backward or twisted, and typically more ascending than those of TABLE 37 Narrow-leaved type. Numbers of apparent mutants and association of the type with doubleness of flowers. Culture Progeny of Snowflake and early parents Total examined11 Narrow-leaved Single Double All Coefficient of mutation 1908 1910 191 IF, house-sown Al! above All unseleeted 725b 338 2072 3135 2410 0 1 7 8 8 2 4 12 18 16 2 6 20 28 26 .28 ± .26 1.78 * .38 .97 ± .15 .89 * .12 1.08 =*= .14 a See note b to table 2. b See note c to table 1. Snowflake. The apex of the leaf is often more acute than with Snow- flake, and many leaves are mucronate or at least end in a sharp, rigid tip. A striking characteristic is the narrowness of the sepals, resulting in frequent early separation at the edges, partially exposing the petals in immature buds. Under the less favorable field conditions the plants often remain long as dwarf rosettes, and flower late and feebly if at all. Figures 23 and 24 show comparatively well developed plants in the field. The type is on the whole very distinct in the field, though there has been some question whether a greenhouse plant such as that in figure 18 is genetically different from those with short and rigid leaves (figs. 22 and 24) ; the very great variability in leaf form due to external conditions makes such a question very difficult without extensive progeny tests. It is now (1918) probable that narrow-dark (p. 143) was not distinguished from narrow in the greenhouse. [141] MISCELLANEOUS STUDIES o 2 u ^^ °* •-I iH N O CO _. Sid- S3 Si 2 CO t-l t~- r-> If. 1 • 3 o" £" o? — — — 5 3 = do Q occo -^ ^ «c 01 O x-s CO •— ' CS "5 I— 1 CO »H 1-H f— t d N.^SB. S **^S *^.' +*.*' en 00"3 CO O O 1-1 1-1 "3 -# % al * CO >O C4 o c -H -H -H 9 - S CC i— 1 i— 1 _2 TjJ t« •< « O ^ Ci i Ej p ^ c e 3 5 1C — , where n p = 49.0 per cent, g = 51.0 per cent, and n= 357. These 357 progeny, as table 39 indicates, came from 20 parents which contributed an average of 17.85 progeny each, and the actual standard deviation of the percentage in these 20 sibships was 10.7 per cent. Obviously the expected standard deviation of simple sampling for comparison must represent samples not of 357 plants each but of 17.85 plants each. Now a percentage is obviously a mean (of values all either 0 or 1). Since "Student" (1908) has shown that the theoretical standard deviation of the mean in samples is given more exactly by °°varlate ,-1 -i O" variate we have o-mean = , where >n = 17.85. This gives a theoretical standard devia- tion of 13.0 per cent.22 It is true (Yule, 1911, p. 260) that the ordinary method of calcu- lation of the actual standard deviation is not satisfactory for means when the samples vary in size. A method has been used, however, which obviates this difficulty, so that comparison with the results given by j - Q ig strictly legitimate. Each squared percentage deviation 71 o has been weighted by multiplying it by the number of individual plants which it represents, and the summation of squared deviations has then been divided, not by 2/, the number of samples, but by 2/ X w, the number of samples multiplied by the mean weight or average size of sample (in other words, by N, the total number of individuals).23 22 In the calculations for table 39 p has been taken as the percentage given in this table, to two decimal places, while with all other numbers employed in calculation, including n — 3, three or more decimal places have been used as needed. 23 Algebraic proof of the correctness of the method has kindly been furnished by Frank L. Griffin, Professor of Mathematics, Reed College, Portland, Oregon. If it develops that this rather obvious device has not been suggested for the purpose, it is to be presented elsewhere with the mathematical proof. When the variates are not grouped in classes the calculation is substantially as easy as without weighting, while the theoretical value is found with much less work than by the method given by Yule (1911, p. 260), which requires the harmonic mean of the sample sizes. [147] 290 MISCELLANEOUS STUDIES II « o SJ «* s o to '«? c I a 1 ^o .0 - g •2 1—1 • t C^ Is* I-H *C CO CO 0 ^ •3 || 1 1 00 Cv •3 CD i-H Tt< 00 to •3 •s CO1*? ICCC 00»CQ O O t^ O .2 "a o o a <-l(N (NO OCOO O § 1C O 0 0 S 06 a — I a O 1 o 0 £ 'j US — ^ ^~. 1 o c B c OC 00 O (N IN CO O CO ll a C3 (N »-" O »C CO "3 fH CD •-H 00 •<* 1C 1| •3 s |f c O a is 1 03 •c | "o CD CO O O •* (N -* CO 1-1 IN CO 00 CO 22 §0 1 1 CD Tf Oi CO O O C ^[s~> >! h~* cc ^ "S ws~' — S "^ ^"^^ "** ^> •*•* 03 ^^ "S ** o *» ^\ 3 i-1 fH ^> T £} ^ j^ O T S^ 0} " u ^ o £ bc"o a> II g II T3 _>> II ^iJs ^c "^•a'3 ^ SI is 9 02 ^ II > J^ 5g| || ||.| | £.| 111 * 1 o "S CO I1 no -^ the number of cultural groups or (with the first line for each type) the number of parents (/), the average size of the groups of progeny (M), and the mean per- centage of the mutant type (p). This serves as a summary of some of the most important statistical data already presented relating to the inheritance of these types, and also shows the basis of the remain- ing part of this table and of table .40. For comparison of actual and theoretical standard deviations the theoretical value has been calculated from the actual percentage as given in this table. For comparison of means (table 40) the percentage of the corresponding total (p0) has also been used, this theoretical standard deviation being the second in the table in the cases where the two values are not identical. Since small changes in a percentage have little effect on its theoretical standard deviation, we are fairly well justified in taking the latter, as calculated from the actual percentage in each case, to be the ''population" value. Consequently, the difference between the theoretical and actual standard deviations has been expressed in each case as a multiple of the probable error of the theoretical value. Aside from the last line for crenate-leaved, where there is an obvious artificial reason for high variability, there is no very significant difference except with slender. In this case, the deviation of 5.7 times the probable error (line 1) is probably largely due to the genetic differentiation of "extreme" and "ordinary" parents suggested by their appearance and by the wide difference in the heredity per- centages; the differences become moderate when the progeny of the two classes of parents are separated. [149] 292 MISCELLANEOUS STUDIES In the two cases (smooth-leaved and crenate-leaved types) where the percentages of mutant types differ greatly with good and poor germination, separation according to germination gives a mean value of the standard deviation decidedly lower than the value for all lots taken together. In the case of the large-leaved type there is little change, while the considerable reduction with the slender type is probably due to unequal separation of lots from parents genetically different. Table 40 shows the simple-sampling probability of the most striking differences of heredity percentages, aside from the characteristic differences between different types. "Student's" (1917) table of probabilities of mean deviations with small samples is used, with interpolation by second differences. Where the standard deviation of the difference is required it is found from the theoretical values given in table 39 by the formula (Yule, 1911, pp. 264-265) — -»/ I _1^ ^0 ^0 I Muller's (1918) complete report on the beaded-wing case in Drosophila appeared several months after the present paper had gone to the publisher. Certain conclusions given below, very similar to Muller's but not credited to him, were therefore reached independently. [153] 296 MISCELLANEOUS STUDIES In the Drosophila case just mentioned, the "principal" factor for the character in question is "dominant for its visible effect and recessive for a lethal effect," so that no pure beaded individuals appear among the progeny of beaded. The original race regularly gave progeny partly heterozygous beaded and partly homozygous normal, while after a long period of selection a true-breeding beaded race appeared. This latter form, it proved, fails to give normals not because of being duplex for beaded — it is still simplex — but because of its possession of another factor, known only by its lethal effect when homozygous, which is carried by the chromosome bearing the normal allelomorph of the factor for beaded. The locus of this reces- sive lethal factor gives in general about 10 per cent of crossovers with the locus of beaded, but in this case, because of the presence of a factor "which almost entirely prevents crossing over" between the loci of the two lethal factors, viable non-beaded zygotes are very rarely produced. Thus every zygote receiving either two beaded-carrying chromosomes or two non-beaded-carrying chromosomes of the pair concerned fails to develop, and all the insects produced are necessarily heterozygous for both lethal factors. A point of special interest in this case is the fact that by certain crosses individuals can be produced which give certain types among their progeny in very small percentages. Muller suggests that part at least of the supposed mutants of Oenothera may be due to crossing over between chromosomes carrying lethal factors, by which certain recessive factors are permitted to come to expression in viable zygotes. For the inheritance of doubleness of flowers in Matthiola he gives a "balanced-factor" explanation essentially identical with mine (Frost, 1915). There seems to be little reason to doubt that the differential factors for these aberrant Matthiola types have originated by mutation. On the analogy of Drosophila we might expect that the true mutations would be relatively rare, and that most of the apparent mutants, in cases where they appear frequently, would be due to segregation, appearing as the result of crossing over in chromosomes carrying balanced lethal factors. The evidence seems to indicate, however, that the differential factors for the mutant types at all extensively studied are dominant for their visible effects and usually (probably imper- fectly) recessive for a lethal effect, the mutant factors thus being genetically similar to the factor for beaded wings in Drosophila. This would seem to imply the occurrence of certain mutations in pro- [1541 MUTATION IN MATTHIOLA 297 portions as high as about 1 per cent, and a general mutation coefficient of perhaps 4.5 per cent, while the only Mendelian alternative would seem to be some more complex scheme whose satisfactory formulation might require much more extensive hybridization data. To be more specific : ( 1 ) these types are not single recessives, since they are not homozygous but split into the mutant and "normal" types; (2) they are not simple cases of multiple recessives, as has been proposed by Heribert-Nilsson (1915) for Oenothera mutations, since what is on that hypothesis the full dominant type reappears with selfing; (3) if these types are single dominants, as they appear to be, they cannot (barring the action of inhibiting factors) arise from the pure recessive "normal" or Snowflake type by segregation, but only by immediate mutation; (4) they are not simple cases of comple- mentary dominant factors, since they occur among the progeny of selfed parents. We might assume that a "mutant" type depends on two pairs of factors, one homozygous and the other heterozygous, while both pairs are heterozygous in the "mutating" Snowflake parent. Thus the D Ci crenate type might have the zygotic formula -= J— , where d is the d ci factor for double flowers, C a dominant factor for crenate, and / a dominant inhibitor of C, all three loci being situated in the same chromosome, at distances of, say, 16 and 4 units apart, in the order indicated. A Snowflake parent producing crenate progeny would then be -5 — - or -^ — - , and crossover combinations would produce the dci del apparently mutant crenate progeny. The crenate progeny would behave as heterozygous dominants when selfed, and if CC zygotes were non-viable would yield constant Snowflake and inconstant crenate; the extracted Snowflake singles, having the composition Dci -T— r, could not throw crenate individuals except by true mutation of c to C. With selfed Snowflake, if we assume 16 per cent and 4 per cent of crossing over in the two positions, and a 60-per-cent selective elimination of crenate zygotes, all CC zygotes being non-viable, sub- stantially the observed percentages of crenate singles and doubles result.26 20 See page 125, footnote. This scheme agrees fairly well with the results from crossing, and gives almost exactly the observed proportion of total ' doubles (a little over 53 per cent) for selfed Snowflake. Its adequate presentation must be reserved for a later paper. [155] 298 MISCELLANEOUS STUDIES Formerly (Frost, 1916) the hypothesis of frequent dominant mutations seemed the more probable, but there is apparently non- conformable evidence. It is true that the peculiar behavior of the slender type might conceivably depend on an occasional mutation in another locus, or an exchange (Shull, 1914) or duplication of loci, giving two similar or identical factors for slender. An apparently fatal objection, however, is the fact that the supposed mutants seem to show linkage with singleness or doubleness at their origin from Snowflake as well as in subsequent generations — a fact which strongly suggests segregation in the former case. If the apparent mutants are really due to segregation complicated by lethal action, the origin of the complex heterozygosis indicated for Snowflake is doubtful; it may be due to hybridization, but more probably to a gradual accumulation of mutant factors in balanced- lethal combinations. On the analogy of Muller 's Drosophila case, especially, it might be expected that the latter would be the true explanation, particularly since self fertilization seems to be the rule in Matthiola. On this basis the term mutant type is used with some confidence in this paper, while the aberrant individuals have been called apparent mutants. We must not forget that some of the mutant types may arise, as with Oenothera gigas and 0. lata, by non-disjunction, or reduplication of chromosomes, and that this fact may determine their heredity. This is not to be expected with the types whose factors show apparent coupling with singleness or doubleness, but it might be true of the apparently unlinked smooth-leaved type. A preliminary study of several types show's that the usual somatic number of chromosomes is probably fourteen, but that positive counts are difficult. While it might be very hard to demonstrate the regular presence of one extra chromosome in an individual or a type, it should be easy to decide between the diploid and triploid numbers. The large-leaved type is so strongly suggestive of 0. gigas that it would not be surprising to find the triploid number in the material now on hand for examination. In a preliminary paper on these types the writer (Frost, 1916) discussed some possible relations of mutation, heterozygosis, and partial sterility, with special reference to Oenothera, mentioning the possibility that special prevalence of heterozygosis in the genus may be, "in large part, a result rather than a cause of mutation." This suggestion is evidently justified even if much of the supposed mutation of Oenothera is really segregation, since it is highly probable that f!56] MUTATION IN MATTHIOLA 299 the peculiar phenomena depend on lethal factors or combinations of factors originally due to mutation. Another possibility there mentioned, advanced by Belling (1914) and since specially discussed by Goodspeed and Clausen (1917), is that of the occurrence of lethal combinations of certain factors which in other combinations may be in no way prejudicial to normal develop- ment. As the latter paper shows, it is probable that in certain crosses between ' ' good species ' ' most of the new combinations brought together in the formation of Px gametes are incompatible with the production of functional gametes. Perhaps in the case of Oenothera there may exist within a species factors lethal in any combination when homozygous, and other factors lethal only in certain com- binations. A balanced-factor explanation for the inheritance of doubleness27 in Matthiola, a case which Muller (1918) discusses, seems to have been first definitely stated by Goldschmidt (1913), though he failed to pro- vide for one feature of the evidence, the deviation of the heredity ratio from 50 per cent. As has been shown (Frost, 1915), this peculiarity may be due to greater viability of the homozygotes (sterile doubles) during embryonic development, since the doubles are more viable in the mature seeds and more vigorous in later development (Saunders, 1915). In this case the "normal" factor is completely eliminated in favor of the mutant (sterile-double) factor in the formation of the sperms, and probably is partially eliminated in the formation of either the eggs or the embryos or both. Here the normal singleness (sporophyll) factor D may act as a lethal in the heterozygous parent, possibly from its general relations of growth vigor in the presence of the more vigorous d-carrying cells. If the lethal factor is situated in a distinct locus, evidently crossovers are at most extremely rare. It is true that Miss Saunders (1911) finds that Fj hybrids with pure single forms produce functional single-carrying pollen ; with the pure single forms from which the original "double-throwing" mutants arose, however, this might not be true, or a lethal change may have occurred in the singleness factor itself rather than in a factor coupled with it. The Drosophila case would suggest a lethal change in another locus of the single-carrying chromosome. In my paper of 1915 this lethal change in one chromosome ap- parently accompanying the mutation of D to d in the homologous 27 For a brief outline of the genetic behavior of doubleness see the discussion of the experimental data for the smooth-leaved type. [157] 300 MISCELLANEOUS STUDIES chromosome was considered puzzling. Evidently, however, it may have occurred in one chromosome before D mutated to d in the other, and even then may have produced its lethal effect. It is evident that if doubleness should arise in the absence of the lethal effect it would tend to be eliminated by the return of one-third of the singles to the homozygous condition in each generation. In fact, it is possible that the lethal change arose later than doubleness, as in the Droso- phila case, or was brought in later by cross pollination, and happened to be preserved as a result of horticultural selection for a high pro- portion of doubles. A parallel-column comparison between the double type and the types especially discussed above has already been given, in connec- tion with the smooth-leaved type. It will now be seen that this com- parison seems to apply to all mutant types, except early, that have been genetically tested, the principal differences between these types relating to the heredity percentage and the apparent presence or absence of linkage with the single-double factors. From the standpoint of its relation to genetic analysis the double- ness factor is remarkably similar to the sex factor in animals. There are two types in each generation, one heterozygous and the other evidently homozygous, and these types are produced by the fertiliza- tion of two kinds of eggs, produced in equal or nearly equal numbers, by a single kind of sperm. Although one of the somatic types is sterile, and the uniformity of the sperms produced by the other is due (evidently) to lethal action, the opportunity for chromosome analysis is similar to that with sex chromosomes. We may say that the doubleness factor and its normal allelomorph (d and D) are carried by chromosome pair I. Already we know several other pairs of factors evidently carried by this pair of chromo- somes. These are, to name only the mutant or possibly mutant member of each pair of factors: P (pale sap color) and W (colorless plastids), both studied by Miss Saunders (1911, 1911a) ; C (crenate- leaved), S (slender; possibly two factors), and N (narrow-leaved). As we have seen, the last three of these are probably lethal when homozygous, and one or more unidentified lethal factors may be con- cerned in the breeding results, while the doubleness factor affects the race much like a recessive lethal, since all dd individuals are completely sterile. [158] MUTATION IN MATTHIOLA 301 SUMMARY This paper describes the occurrence, characteristics, and heredity of certain aberrant plant types which decidedly resemble some of the " mutant" types produced by Oenothera lamarckiana. The parent form is Matthiola annua Sweet, of the horticultural variety "Snow- flake." These aberrant forms may be called mutant types, since it is highly probable that they are originally produced by mutation. The aberrant individuals may be termed apparent mutants, since it may be con- sidered uncertain whether they usually- arise by immediate mutation or by segregation. The case acquires special significance because indi- viduals belonging to the mutant types, although the species is known to be typically Mendelian with respect to various characters, give erratic heredity ratios suggestive of Oenothera. At least eight types have been somewhat carefully studied, and six of these have shown their heritability in progeny tests. Several other types have been named, but for various reasons their distinctness is more or less doubtful. Some of the commoner types have each been produced by many parents, and in several pure lines isolated from the original com- mercial variety. The apparent mutants other than the early type com- pose about four or five per cent of the progeny of Snowflake and early parents, the separate types ranging down from about one per cent. Most of the mutant types are in general inferior to Snowflake in vigor, and the difference in development is greatly increased by certain unfavorable environmental conditions. The proportion of apparent mutants in cultures from Snowflake parents appears to be definitely lower where germination is comparatively poor. The mutant types differ from Snowflake and from each other in various respects. The early type is practically a smaller and earlier Snowflake. The other mutant types, on the other hand, differ markedly from Snowflake in vigor, fertility, and various form and size char- acters. Each type is named from some conspicuous characteristic difference from Snowflake, but usually various other differences can readily be found. Somewhat extensive progeny tests have been made for five of the mutant types, and a little evidence secured for two or three other types. [1591 302 MISCELLANEOUS STUDIES The early type is probably due to a single dominant mutant factor segregating normally from the corresponding Snowflake factor; the quantitative nature of its differences from Snowflake, however, makes positive determination of this point a matter of great difficulty. At least five other types plainly reproduce themselves, but about 50 to 70 per cent of the progeny are usually Snowflake; no true- breeding individual of any generation of any of these types has yet been tested. Genetic work with most of these types has been much hampered or even prevented by low vigor and fecundity, and the aggregate data from progeny of parents of four types strongly indi- cate selective viability at germination. It has been determined by crossing that in three of the types the mutant factor (or factors) is carried both by eggs and by sperms. From these facts it seems prob- able that homozygotes of the mutant types are non-viable, and that severe selective elimination occurs during embryonic development; or, in other words, that the mutant factor is imperfectly recessive for a lethal effect. In three types there appears to be linkage with the factor pair for singleness and doubleness of flowers, the mutant factor being coupled with singleness in the tested apparent mutants of two types, and with doubleness in the third type. AA7ith two other types these factors seem to be independent. No reversal of coupling has been found in later generations of the former two types, but on the scheme presented crossover singles should be scarce. For one type (crenate-leaved) a hypothesis based on the facts stated gives very closely the ratio obtained from selfed parents. Reciprocal crosses with Snowflake conform less closely to the requirements of the hypothesis, but do not definitely contradict it. The slender type, which shows similar apparent linkage, seems to disagree definitely with the hypothesis; there is strong evidence, however, that slender individuals may differ genetically among themselves. r A more complex scheme providing also for the usual origin of these types from Snowflake by segregation is briefly outlined. The selfing ratios are very suggestive of duplication of a chromo- some (non-disjunction), as in Oenothera lata, but it is hard to reconcile the cases of apparent linkage with this hypothesis. It seems probable that these three linked types have originated and are trans- mitted in the same general way as the double-flowered type, and that all of these four mutant factors (including double) represent changes of some sort within a chromosome of the same .pair, which may be [160] MUTATION IN MATTHIOLA 303 numbered I. Miss Saunder's work shows that two flower-color factors also belong to this linked group. The large-leaved type strikingly resembles Oenothera gigas, and it may prove to be triploid in nuclear constitution. In that case segrega- tion may be irregular and genotypically intermediate individuals may be more or less frequently produced. It is probable that further study of these types will help to explain the remarkable genetic behavior of Oenothera and of Citrus. LITERATURE CITED* ATKINSON, GEORGE F. 1917. Quadruple hybrids in the F1 generation from Oenothera nutans and Oenotltera pycnocarpa, with F.. generations and back- and inter- crosses. Genetics, vol. 2, pp. 213-260, 11 tables, 1 diagr., 15 figs. BABCOCK, ERNEST B. 1918. The role of factor mutations in evolution. Am. Naturalist, vol. 52, pp. 116-128. BARTLETT, H. IT. 1917. Mutation in Matthiola annua, a "Mendelizing" species. [A review of paper of same title by H. B. Frost.] Bot. Gaz., vol. 63, pp. 82-83. BATESON, WLLIAM, AND SAUNDERS, EDITH R. 1902. Experimental studies in the physiology of heredity. I. Experiments with plants. Matthiola. III. Discussion. Roy. Soc. London, Re- ports to the Evolution Committee, vol. 1, pp. 32-87, 125-160, 15 tables. BATESON WILLIAM, SAUNDERS, EDITH R., AND PUNNETT, REGINALD C. 1905. Experimental studies in the physiology of heredity. Matthiola. Roy. Soc. London, Reports to the Evolution Committee, vol. 2, pp. 5-44, tables. 1906. Ibid. Stocks. Ibid., vol. 3, pp. 38-53, 4 tables, 2 figs. BATESON, WILLIAM, SAUNDERS, EDITH R., PUNNETT, REGINALD C., AND KILLBY (Miss) H. B. 1908. Experimental studies in the physiology of heredity. Stocks. Roy. Soc. London, Reports to the Evolution Committee, vol. 4, pp. 35-40, 3 tables. BELLING, JOHN. 1914. The mode of inheritance of semi-sterility in the offspring of certain hybrid plants. Zeitsehr. f. indukt. Abstam.- u. Vererbungsl., vol. 12, pp. 303-342, tables, 17 figs. BI.AKESLEE, ALBERT F., AND AVERY, B. T. JR. 1919. Mutations in the jimson weed. Jour. Heredity, vol. 10, pp. 111-120, 11 figs. * An asterisk prefixed to the date indicates that the paper cited has not been seen by the present writer. [1611 304 MISCELLANEOUS 8TUDIK* COBRENS, CARL E. 1900. fiber Levkojenbastarde. Zur Kenntniss der Grenzen der Mendel 'schen Regeln. Bot. Centralbl., vol. 84, pp. 97-113. 1902. Scheinbare Ausnahme von der Mendel 'schen Spaltungsregel fur Bas- tarde. Deutsch. bot. Ges., Ber., vol. 20, pp. 159-172, 4 tables. DAVIS, BRADLEY, M. 1917. A criticism of the evidence for the mutation theory of de Vries from the behavior of species of Oenothera in crosses and in selfed lines. Nat. Acad. Sci., Proc., vol. 3, pp. 705-710. FROST, HOWARD B. 1911. Variation as related to the temperature environment. Am. Breeders' Assoc., Ann. Bept., vol. 6, pp. 384-395, 4 tables, 4 charts. 1912. The origin of an early variety of Matthiola by mutation. Ibid., vol. 8, pp. 536-545, 5 tables. 1915. The inheritance of doubleness in Matthiola and Petunia. I. The hypotheses. Am. Naturalist, vol. 49, pp. 623-636, 1 fig., 2 diagr. 1916. Mutation in Matthiola annua, a "Mendelizing" species. Am. Jour. Bot., vol. 7, pp. 377-383, 3 figs. 1917. A method of numbering plants in pedigree cultures. Am. Naturalist, vol. 51, pp. 429-437. GATES, E. EUGGLES. 1935. The mutation factor in evolution. London, Macmillan, xiv + 353 pp., 1 map, 114 figs., bibl. GOLDSCHMIDT, ElCHARD. 1913. Der Vererbungsmoclns der gefiillten Levkojenrassen als Fall geschlechts- begrenzter Vererbung? Zeitschr. f. indukt. Abstain.- u. Verer- bungsl., vol. 10, pp. 74-98, diagr. 1916. Nochmals iiber die Merogonie der Oenotherabastarde. Genetics, vol. 1, pp. 348-353, 1 pi. GOODSPEED, THOMAS H., AND CLAUSEN, E. E. 1917. Mendelian-factor differences versus reaction-system contrasts in hered- ity. Am. Naturalist, vol. 51, pp. 31-46, 92-101. HERIBERT-NILSSON, N. *1915. Die Spaltungserscheinungen der Oenothera lamarclciana. Lunds Univ. irsskrift, vol. 12, pp. 4-131. (Eeview by Ben C. Helmick in Bot. Gaz., vol. 63, 1917, pp. 81-82.) MULLER, HERMANN ,T. 1917. An Oenothcra-like case in Drosophila. Nat. Acad. Sci., Proc., vol. 3, pp. 619-626. 1918. Genetic variability, twin hybrids and constant hybrids, in a case of balanced lethal factors. Genetics, vol. 3, pp. 422-499', 1 table, 1 fig., 1 diagr. SAUNDERS, EDITH E. 1911. Further experiments on the inheritance of doubleness and other char- acters in stocks. Jour. Genetics, vol. 1, pp. 303-376, 8 tables. 1911a. The breeding of double flowers. Fourth Intern. Conf. on Genetics, Proc., pp. 397-405, diagr. "1913. Double flowers. Eoy. Hort. Soc., Jour., vol. 38, pt. 3, pp. 469-482. [16-21 MUTATION IN MATTHIOLA 305 1913a. On the mode of inheritance of certain characters in double-throwing stocks. A reply. Zeitschr. f . indukt. Abstam.- u. Vererbungsl., vol. 10, pp. 297-310. 1915. A suggested explanation of the abnormally high records of doubles quoted by growers of stocks (Matthiola). Jour. Genetics, vol. 5, pp. 137-143, 3 tables. 1916. On selective partial sterility as an explanation of the behavior of the double-throwing stock and the petunia. Am. Naturalist, vol. 50, pp. 486-498. SHULL, GEORGE H. 1914. Duplicate genes for capsule form in Bursa bursa-pastoris. Zeitschr. f. indukt. Abstam.- u. Vererbungsl., vol. 12, pp. 97-149, 5 tables, 7 figs. ' ' STUDENT. ' ' 1908. The probable error of a mean. Biometrika, vol. 6, pp. 1-25, tables, 4 diagr. 1917. Tables for estimating the probability that the mean of a unique series of observations lies between — <*> and any given distance of the mean of the population from which the sample is drawn. Ibid., . vol. 11, pp. 414-417, tables. SWINGLE, WALTER T. 1911. Variation in first-generation hybrids (imperfect dominance): its pos- sible explanation through zygotaxis. Fourth Intern. Conf. on Genetics, Proc., pp. 381-393, 10 figs. TSCHERMAK, ERICH VON. *1904. Weitere Kreuzungsstudien an Erbsen, Levkojen u. Bohnen. Zeitschr. f. d. landw. Versuchswesen in Oesterreich, 1904, pp. 533-638. 1912. Bastardierungsversuche an Erbsen, Levkojen, und Bohnen mit Riick- sicht auf die Faktorenlehre. Zeitschr. f. indukt. Abstam.- u. Verer- bungsl., vol. 7, pp. 81-234, tables. WEBBER, HERBERT J. 1906. Pedigree records used in the plant-breeding work of the Department of Agriculture, in L. H. Bailey, Plant Breeding CNew York, Mac- millan), pp. 308-319. DE VRIES, HUGO. 1906. Species and varieties: their origin by mutation. Ed. 2, Chicago, Open Court Pub. Co., xviii + 847 pages. 1918. Twin hybrids of Oenothera hookeri T. and G. Genetics, vol. 3, pp. 397- 421, 14 tables. 1919. Oenothera rubrinervis, a half mutant. Bot. Gaz., vol. 67, pp. 1-26, tables. YULE, G. UDNY. 1911. An introduction to the theory of statistics. London, Charles Griffin & Co., xiii + 376 pages, 53 figs. fi6»l 306 MISCELLANEOUS STUDIES PLATE 22 THE EARLY TYPE Fig. 1. March 20, 1908. The single progeny of WG9. Plants from house M to the reader's left from stake, from house W to right of stake, from house C below. WG9-C10, the early apparent mutant, is the middle plant in the lower row. The stake indicates inches. Fig. 2. About May 1, 1908. WG9-C10 at the left, WG9-C9 (Snowflake) at the right. [164] MUTATION IN MATTHIOLA 307 Fig. 1 Fig. 2 308 MISCELLANEOUS STUDIES PLATE 23 THE EAKLY TYPE Fig. 3. April 8, 1909. The single progeny of WG9-C9 (Snowflake); arrange- ment as in figure 1. Fig. 4. April 9, 1909. The single progeny of WG9-C10 (heterozygous early). Warm-house plants partly at right of stake in lower row; arrangement other- wise as in figure 3. Compare with figure 3, house by house. [166] MUTATION IN MATTHIOLA 309 Fig. 3 Fig. 4 | FROST ] PLATE 23 310 MISCELLANEOl'S STl'lHKS PLATE 24 THE EARLY TYPE Fig. 5. July 19, 1911. Lots 1 to 10, with lots 11 to 14 mostly in sight at the right. Odd-numbered lot in nearer (west) half of each row. Fig. 6. July 19, 1911. Lots 19 to 28, with lots 15 to 18 mostly in sight at the left. (168! MUTATION IN MATTHIOLA 311 Fig. 5 Fig. 6 [ FROST 1 PLATE 24 312 MISCELLANEOUS STUDIES PLATE 25 THE SMOOTH-LEAVED TYPE Fig. 7. April 27, 1909. Smooth-leaved apparent mutants. Compare with figures 3 and 4 as to earliness, noting the difference in date. Fig. 8. May 29, 1914. Progeny of a smooth-leaved parent. Plant at right Snowflake single, the others smooth. [170] MUTATION IN MAT TRIO LA 313 Fig. 7 Fig. 8 [ FROST ] PLATE 25 314 MISCELLANEOUS STfHlKS PLATE 26 THE SMOOTH-LEAVED TYPE Fig. 9. June 28, 1915. Progeny of a smooth-leaved parent. Smooth single at left, Snowflake double at right. Fig. 10. Same date and parent as with figure 9. From left to right: Snow- flake double (also shown in figure 9), Snowflake single, smooth double. 1172] MUTATION IN MATTHIOLA 315 Fig. 9 Fig. 10 [ FROST ] PLATE 26 316 MISCELLANEOUS STUDIES PLATE 27 THE LARGE-LEAVED TYPE Fig. 11. August 29, 1914. Progeny of a large-leaved parent (28a), near the close of the hot Riverside summer. From left to right: large single, large double, Snowflake single (two, the first injured by aphids). 11741 MUTATION IN MATTHIOLA 317 Fig. 11 f FROST 1 PLATE 27 3is M i. ST /•;/./.. i. \i-:nfs PLATE 28 THE LARGE-LEAVED TYPE Fig. 12. July 8, 1916. Progeny of a large-leaved parent. Middle plant Snowflake; the rest large; all single. Fig. 13. July 8, 1916. Progeny of a large-leaved parent, more than a month older than those shown in figure 12. From left to right: large double, Snow- flake double, large single. [176] MUTATION IN MATTHIOLA 319 Fig. 12 Fig. 13 FROST | PLATE 28 320 MISCELLANEOUS STUDIES PLATE 29 THE CREXATE-LEAVED TYPE Fig. 14. April 6, 1909. Crenate-leaved apparent mutants. Note the varia- tion in leaf serration, and especially the slightness of the serration (or crenation) with the one cool-house plant (below). Fig. 15. April 14, 1911. Progeny of a crenate-leaved parent, grown in a cool greenhouse. The first two plants at the right are Snowflake, the rest crenate. [178J MUTATION IN MATTHIOLA 321 Fig. 14 Fig. 15 [ FROST ] PLATE 29 322 MISCELLANEOUS STWIKS PLATE 30 THE CRENATE-I.EAVED TYPE Fig. 16. July 8, 1916. Progeny of a crenate-leaved parent. From left to right: crenate single (two), crenate double, Snowflake double. Fig. 17. July 8, 1916. Snowflake X crenate-leaved, F,. From left to right: smooth, Snowflake single, crenate double (two). [1801 MUTATION IN MATTHIOLA 323 Fig. 16 Fig. 17 [ FROST 1 PLATE 30 324 MISCELLANEOUS STUDIES PLATE 31 THE SLENDER TYPE Fig. 18. April 27, 1909. Miscellaneous aberrant individuals, with two typical Snowflake plants (third from the left above, second from the left below). In upper row: second from left, narrow double; second from right, slender double. In lower row at left, slender single (25b). Fig. 19. April 14, 1911. Progeny of a slender parent (25b). Two at the right Snowflake, the rest slender. 1182] MUTATION IN MATTHIOLA 325 NT1R-W | " ' T T I Fig. 19 [ FROST | PLATE 31 326 MISCELLANEOUS STI'DIK* PLATE 32 THE SLENDER TYPE Fig. 20. June 3, 1914. Progeny of slender parents. From left to right: slender single, slender double, Snowflake double. Fig. 21. July 7, 1916. Snowflake X slender, F,. Middle plant Snowflake; the others slender; all single. 1184] MUTATION IN MATTHIOLA 327 ,. . ::i's MISCELLANEOUS STUDIES PLATE 33 THE NARROW-LEAVED TYPE Fig. 22. April 13, 1911. Narrow-leaved apparent mutants. Fig. 23. June 3, 1914. A narrow-leaved apparent mutant among progeny of a crenate-leaved parent. From left to right: narrow double, crenate single (two). [186] 329 Fig. 22 Fig. 23 FROST 1 PLATE 33 330 MISCELLANEOUS STUDIES PLATE 34 THE NARROW-LEAVED AND SMALL-SMOOTH-LEAVED TYPES Fig. 24. June 28, 1915. A narrow-leaved apparent mutant among F, progeny from Snowflake X slender. Narrow double at left; the rest Snowflake single. Fig. 25. April 14, 1911. Miscellaneous aberrant plants, some being apparent mutants. From the left: first and fifth small-smooth, third stout dwarf, seventh slender. See text. [188] X MUTATION IN MATTHIOLA 331 Fig. 24 Fig. 25 [ FROST ] PLATE 34 332 MISCELLANEOUS STUDIES PLATE 35 THE NARROW-DARK-LEAVED TYPE Fig. 26. June 3, 1914. A narrow-dark-leaved apparent mutant among progeny of a narrow-leaved parent. Third plant from left narrow-dark single; the other three Snowflake double. Fig. 27. June 28, 1915. Progeny of a "small-convex-leavedC?) " parent (27a). From left to right: narrow-dark single, Snowflake double, smooth single. [190] MUTATION IN MATTHIOLA 333 Fig. 26 Fig. 27 [ FROST | PLATE 35 OCEAN TEMPERATURES BY GEORGE F. McEWEN OCEAN TEMPERATURES, THEIR RELATION TO SOLAR RADIATION AND OCEANIC CIRCULATION QUANTITATIVE COMPARISONS OF CERTAIN EMPIRICAL RE- SULTS WITH THOSE DEDUCED BY PRINCIPLES AND METHODS OF MATHEMATICAL PHYSICS BY GEORGE F. McEWEN Oceanographer of the Scripps Institution for Biological Research of the University of California CONTENTS PAGE Introduction. The place of mathematical methods in researches on oceano- graphic problems 337 Solar radiation and surface temperature, assuming the average rate of flow of the water to be zero : 338 Preliminary discussion, and statement of certain generally accepted conclusions as to the process by which the water gains and loses heat 338 Statement of assumptions, mathematical formulation of the problem and its solution 339 Determination of the numerical values of the constants in the solution.... 344 Observed and theoretical lag of temperature maxima and minima behind the radiation maxima and minima; comparison of computed and observed normal temperatures 348 Numerical estimates of the coefficient of absorption of solar radiation in sea water 350 Deduction of the change in surface temperature produced by a horizontal flow of water 352 Preliminary discussion, statement of assumptions, and mathematical formulation of the problem 352 Solution for the case in which the flow is constant 356 Solution for the case in which the flow is a periodic function of the time.... 359 Solution for the particular case in which the time interval is so small that the solar radiation may be assumed to depend only upon the ' latitude 360 The rate of horizontal flow in the North Pacific off the California coast from latitude 40° N to 30° N and in the North Atlantic off the west coast of Africa from latitude 30° N to 20° N 362 The rate of flow off the coast of California deduced from surface tem- peratures 362 The rate of flow deduced from temperature data compared with that ex- pected from the empirically ascertained relation of winds to currents and with direct observations on currents \ 363 The surface current prevailing for a short time interval near the north- west coast of Africa, estimated from surface temperatures, com- pared with direct observations and with results deduced from the empirically ascertained relation of winds to currents 364 336 MISCELLANEOUS STUDIES The relation of the temperature to time, depth and rate of vertical flow in the depth interval from 40 to 600 meters 367 Statement of assumptions and mathematical formulation of the problem 367 Solution for the case in which the vertical flow is constant 369 Solution for the case in which the vertical flow is a periodic function of the time 372 Numerical values of the constants in the solution, determined from tem- perature observations in the Pacific near San Diego ... 374 Comparison of theoretical and observed monthly temperatures at depths from 40 to 600 meters in the San Diego region 382 Solution of the problem of temperature reduction due to upwelling, with numerical applications relative to the 40 meter level in the San Diego region 382 Deduction of the change in surface temperatures due to a vertical flow of water near the surface 388 Statement of assumptions and mathematical formulation of the problem and solution for the case in which the flow is coastant 388 Solution for the case in which the flow is a periodic function of the time.... 391 Theoretical reduction of the surface temperature for each month in the San Diego region due to upwelling, and comparison with observations 393 Deductions relative to oceanic circulation in the San Diego region, based on Ekman's hydrodynamical theory 397 Deduction of the upwelling velocity in the San Diego region from the observed relation of salinity to depth, and comparison with that deduced from tem- perature data 406 Conclusion 415 Literature cited.... ....419-421 OCEAN TEMPEEATUEES 337 INTRODUCTION THE PLACE OP MATHEMATICAL METHODS IN RESEARCHES ON OCEANOGBAPHIC PROBLEMS The present paper deals with the formulation and solution of several quantitative problems suggested by data on ocean winds, temperatures, and circulation. Before formulating these problems a brief general discussion of the place of mathematical methods in oceanographic researches is given. The process of testing physical laws in the laboratory is greatly facilitated by devising appropriate experiments in which the variables are largely under the control of the investigator. Even under these favorable conditions the actual phenomena are too complex for de- tailed representation in a mathematical formula, and an appropriate simplification by abstraction is required to formulate problems that are amenable to mathematical treatment. This is true in a much greater degree of the more complex phenomena occurring in nature; yet a rigorous mathematical treatment of natural problems capable of yielding results in agreement with observations, while in general more difficult, is necessary and fully justifies the increasing attention being given to terrestrial and cosmic physics. The actual phenomena of heating and cooling of the water in the ocean are far too complex to be considered in detail. Therefore, in order to apply rigorous mathematical reasoning to these phenomena, it is necessary to devise a comparatively simple ideal system which would behave in essentially the same way as the actual one with reference to the observations in question. Certain problems can then be formulated definitely in such a way as to permit of the precise calculation of results, the comparison of which with observations tests the practical value of the abstract system. It is fortunate for the problems considered in this paper that the proper choice of the simple assumptions needed in devising the ideal system is facilitated by certain general results of numerous and extended ocean as well as laboratory observations. An abstract system founded on such assumptions would in general agree much better with the conditions in nature than one in which the assumptions were hypo- thetical or carried over from some other field. Evidently deductions from any group of simple assumptions cannot have the same degree 338 MISCELLANEOUS STUDIES of certainty as direct observations, since the ideal system cannot con- form accurately to all the details of the phenomena of the actual one. However, if in this way a logical and reasonably accurate description of a wide range of physical quantities is obtained there is good reason to believe that deductions or predictions relative to quantities not yet observed will be in agreement with the facts. This is especially true if two or more lines of reasoning converge to the same conclusion. When it is impossible or impracticable to make the appropriate direct observations the theoretical results must be regarded as the best estimates, even though it is not impossible that future observations may show important deviations from theory. Finally, while the exist- ing observations may be logically described by means of the ideal system, and deductions based on it, extended results reached by apply- ing purely deductive methods to the ideal system are not substitutes for a correspondingly extended series of new observations. The neces- sity for making observations will always exist. SOLAR RADIATION AND SURFACE TEMPERATURE, ASSUMING THE AVERAGE RATE OF FLOW OF THE WATER TO BE ZERO Preliminary discussion, and statement of certain generally accepted conclusions as to the way in ichich the water gains and loses heat. In order to have a basis for estimating the effect of circulation on ocean temperatures it is necessary to work out quantitatively the rate at which the heat of the water is gained and lost under the more simple condition of no flow. This will be done by devising an ideal ocean, based on assumptions agreeing as nearly as possible with the following conclusions which are founded on numerous and widely extended ocean observations. 1. The primary source of heat is the radiant energy of the sun. both direct and diffuse, that penetrates the water (Murray, 1912, p. 225, Gehrke, 1910, p. 67, Helland-Hansen, 1911-12, pp. 64-66). 2. Absorption of this radiation directly heats the water in the upper layers (Nansen, 1913, pp. 21-22), and only a small fraction of this radiant energy penetrates below 25 meters (Kriimmel, 1907. pp. 253-270, Helland-Hansen, 1911-12, pp. 65-68, and Knott. 1903-05). 3. There is always a complex vertical circulation (Helland-Hansen, 1911-12, p. 68, Gehrke, 1910, p. 68, Nansen, 1913, p. 21, Murray. 1912, p. 226) due to a lack of balance of the many forces acting on the water particles. The resultant vertical flow through a finite sec- tion due to this motion may be very small and may be either upward OCEAN TEMPERATUBES 339 or downward. That is, at the same time, some portions of the water are moving upward and others downward, thus tending to mix up the water at different levels. In this problem the resultant of the upward and downward flow will be assumed to be zero. 4. This "mixing process" is most intense in the layers nearest the surface, owing to wave motion and other surface disturbances due to wind, but is present in some degree at all depths (Gehrke, 1909, p. 12, Murray, 1898, p. 127). 5. The amount of heat transferred from one level to another by conduction through the water is a negligible fraction of that carried by the water particles themselves as a result of the mixing process (Gehrke, 1909, p. 12). 6. The mean annual rate of change of temperature with respect to latitude is practically independent of the depth within the upper hundred meters. This is revealed by a study of the average tempera- tures of the North Pacific, tabulated with respect to latitude, longitude, and depth (Schott, 1910, p. 14). 7. At the time of year when the surface temperature is a minimum there is practically no variation of the temperature with respect to depth in the upper thirty meters (McEwen, 1916, p. 272). Statement of assumptions; mathematical formulation of the problem and its solution. Let Kl /! (L, t] equaZ Q^ the amount of radiant energy available per month per unit area of horizontal surface at the latitude L and time t, where Kl is proportional to the solar constant and fl (L,t) is a function of the latitude L and the time t. Let Q equal the amount of radiant energy used directly in heating the water, that is, the amount passing into the water. Also let y equal the distance in meters from the surface of the water, the positive direction being downwards, a equal the specific heat of sea water per unit volume, & equal the temperature, centigrade. t equal the time, the unit being 1 month, and t equal 1 for January, 01 equal a temperature assumed to depend only on the latitude and depth y, and /?! equal the average transmission coefficient of sea water for the solar radiation, that is, the proportion of radiation at any level that passes through unit thickness of water measured from that level. 340 MISCELLANEOUS STUDIES Since the solar radiation consists of a series of waves of varying length, each having a different coefficient of transmission (Murray, 1912, p. 248, Kriimmel, 1907, p. 263), the use of a single average value is only a simple approximation to the true relation. No analysis will be attempted of the complex way in which the heat in an element of volume, specified by given values of y and L, is lost. This loss depends upon evaporation at the surface and on the mixing process at all depths, and the rate of evaporation increases as the temperature increases. Also heat tends to flow from regions Fig. 1. of high temperature to those of low temperature (Gehrke, 1910, p. 68). It seems reasonable to suppose, therefore, that the rate of loss would be greater, the greater the temperature. Although the precise manner in which the rate of loss of heat depends upon the temperature is not known, some definite form of relation must be assumed in order to formulate th'e temperature problem mathematically. For simplicity assume the rate of loss at any depth to be proportional to (6 — 0J at that depth, where 0t is a function of the depth and latitude only. Consider now the time rate at which heat is gained and lost in a given rectangular element of volume of unit cross section and thickness dy whose upper surface is at the depth y (fig. 1). The rate of change of heat in this volume element is evidently t (1) since the volume specific heat multiplied by the volume of the element equals the change in the amount of heat per degree change of tem- perature. OCEAN TEMPERATURES 341 The rate of gain of heat in this element of volume due to the absorption of solar radiation equals the difference between the rate at which the radiant energy passes in through its upper surface and out through its lower surface. At the upper surface the rate is QPS and at the lower surface it is Qfl^*dy. Therefore the rate of gain due to absorbed radiation is (2) since = — (log ft The rate of loss of heat will be assumed to be ka(0 — QJdy where k is a function of y only. Equating the rate of change of heat in the element to the rate of gain from solar radiation less the rate of loss, we have the following differential equation (3) which becomes « _ ot after division by ady. Let L = Ll -f- x where Ll is a standard latitude chosen arbitrarily and x is the distance in degrees from this position, x is positive for latitudes higher than Ll and negative for lower latitudes. The function f-i(L, t), (p. 339), then becomes f(x,t), which expresses the way in which the radiation varies with respect to latitude and time. The precise form of f(x,t] is unknown; however, estimates of the amount of radiant energy available at the earth's surface made by Angot (Hann, 1915, p. 40) can be closely approximated to within a ten-degree interval of latitude by an expression of the form Q1 = K1[ (ax -|- a2x) cos at -f- a3x -f- 1] (5) 7T where a =— , and the coefficient of cos at is negative. 6 Assuming the amount of energy Q that enters the water to be pro- portional to the amount available Ql (6) 342 MISCELLANEOUS STUDIES where the constant A' g A',, since the amount of energy used cannot exceed the amount available. Equation (4) then becomes .«.) (7) Let where B is a constant and & = «-* (9) where ft, is the absorption coefficient (Kriimmel, 1907, p. 263). Equation (7) then reduces to the ordinary linear differential equation - + kO=B[(al +o2x) cosaf + asZ + lJe-^ + fc^ (10) Therefore (11) where F(x,y) is an arbitrary function of x and y. Integrating equation (11) gives . asm at -\-kcos at . Be~^v (l-fa,a-) -a2x) - --- \- - --- \-0l (12) which can be readily transformed into v — \suty yi**' «/ i^w I •» I Va2-f fc2 k } where tan« = - (14) k and only the periodic part of the integral is retained. If 0X is assumed to be independent of JT the latitude gradient g of the mean annual temperature is, from equation (13), . (15) Therefore, since g is independent of y (sixth statement, p. 339) k = kle~^ (16) where fc, is a constant. That is, g=2± OCEAN TEMPERATURES 343 Corresponding to the time of year t0 when the surface temperature has the minimum value 00 equation (13) becomes PO = — 1- 6l — j- — T- \- - — (18) Since the coefficient of cos (at — e) is negative (see p. 341) cos (oi0 — e) must equal plus 1 ; therefore from the seventh general statement (p. 339) 01=*t_:*^dbd^ (19) Vo. + " where 03 is a constant. Making use of the results just found equation (13) becomes [cOs(a*-e)-l]+^+r +*3 (20) where The small variation in temperature with respect to depth in the upper six meters indicates that these upper water layers are very thoroughly mixed (Michael and McEwen, 1915, 1916). Accordingly temperatures in this 6 meter interval will be computed by using 3 meters, the average value of the depth. That is, (y — 3) will be substituted for y when the depth exceeds 6 meters and the constant value (6 — 3) =3 for all depths between 0 and 6 meters. From equation (20) it follows that at the time of minimum temperature the temperature is inde- pendent of the depth y in accordance with the seventh general state- ment (p. 339). But the latitude gradient which is the part of the coefficient of x in equation (20) not involving the time is Bo,* e~^lV Ba, . „ - _ _ I 7 ' This is not in accordance with the observed fact that the latitude gradient is independent of y; but the relative error will depend upon the ratio of the first term to the second term, and may not be important. As will be seen later (p. 345) it proves to be a negligible error if we add to $t of equation (19) the term Boxe- Therefore equation (20) with this modification and the use of (y — 3) for the depth y gives the approximate form of the relation between 344 MISCELLANEOUS STUDIES temperature, time, depth, and latitude, in accordance with the assump- tions and general results of temperature observations already stated. The modified equation is 1--2 r , Baa B , Ba2xe-3t» ( 6= *~ 2 -- [cos (atf— £)—!]+- — X + -T-+- +0-3 22 *2 (22) Also from equations (19) and (20) B , Ba.x , B(a1-\-a2x)e-^v-a) cos (at~€} (23) where a a tan c=-=- k AV Determination of the numerical values of the constants in the solution. In applying mathematical methods to physical problems the functional relation between the variables involves certain constants which must be determined from observed values of these variables. The constants in equation (22) are ax a2 az a kl 03 B and b^ Also from equation (8) we have B = — — . The first four constants cr are found by fitting the function •^i [ (ai + a2x) cos °- (equation 5) to the estimated values of solar radiation, as given for example by Angot's tables (Hann, 1915, p. 40). The next three require observations on temperature. For example, they can be found from the observed values of the normal annual range of temperature at a series of latitudes and from the mean annual temperature at these latitudes. The coefficient of absorption ~b^ can be estimated from direct meas- urements of the intensity of radiation in the ocean at different depths (Grein, 1913), or from observations on water samples taken to the laboratory (Petersen, 1912. p. 39). Also an indirect estimate can be made from temperature and solar radiation data (pp. 350-352) by means of equation (22). However, in the problem of surface tem- perature in which the vertical flow is neglected the value of b^ is not required. OCEAN TEMPERATURES 345 Choosing 30° N for the standard latitude Zr1? the data on solar radiation taken from Angot's tables and based on the atmospheric transmission coefficient of 0.60 gives the following values of the first four constants: a=— .0128 = — .0159, a== 0.523. b Ol = — .47 A later and more accurate estimate of the radiant energy available at the ocean's surface (Schmidt, 1915, p. 121) gives smaller values, on the average, than those of Angot; also instead of the value — .0159 53 for az his results give — 01_ -m ~ — -0244, which will be used in ZJ. i /\ JLU in this paper. Kriimmel (1907, p. 413) gives the observed normal mean annual temperature and the normal annual temperature range for the surface of the ocean corresponding to a series of latitudes. These values are in part presented in the following table. range for the surface of the ocean at latitudes 10° N to 50 N North latitude 10° 20° 30° 40° 50° Mean Annual temperature Annual range 27.2 2 2 25.4 3 6 21.3 6 7 14.1 10 2 7.9 8 4 Half Annual range 1.1 1.8 3.35 5.1 4.2 x -20° -10° 00° +10° +20° From the tabulated values it follows that the gradient of the half range is .175 and the gradient of the mean annual temperature is .72 from latitudes 30° N to 40° N. Let mx equal e~abl where 3 is the mean depth of the upper homogeneous layer. From these values and equation (22) we have Va2 = -3.35 = _ I / *l!5l 2\ a ==_i15==Ba2mi ["i I/ fe*m* Y "I ~2\ » / . (24) (25) and (26) 346 MISCELLANEOUS STUDIES in which the last members of equations (24) and (25) are approxi- / k m \ matolv correct if ( — - — - ) is small. Substituting the numerical values of ar a2 az and a from page 345 we have B= Ejmk* = 29'5k* <27> From equations (24) and (27) neglecting -( — — -) we have the first 2 ^ a. ' approximation 29.5*^ X 1-910 X (—.47) = -3.35 (28) from which 3 35 = '' 29.5 X 1.910 X. 47 Therefore 1 + 1/2 (JW±Y = 1.0292 fc^i = 1.0292 X -1265 = .1302 (29) and 29.5 X. 1302 _ 3.84 Similarly from equations (25) and (27) we have 29.5 kimi X 1.910 X -0128 = .175 from which 17n if m — __ • _ — 2427 " 29.5 X 1.190 X .0128 " Therefore i2= 1.1075 1clml = 1.1075 X .2427 = .2688 (31) and „ 29.5 X .2688 7.927 B = - = - . ( oZ ) Wtj Wlt The difference between the values of B and kl found by these two methods of computation is due to the fact that the ratio between the OCEAN TEMPERATURES 347 half range of radiation at the standard latitude to the gradient of the half range of the radiation is not quite consistent with the ratio of the half range of temperature at that latitude to its gradient. It seemed best to take the average of the two values and to apply corrections to a^ and a2, making them agree with the temperature data; then the difference between the corrected values a\ and a'2 and the original values will indicate the magnitude of this discrepancy between temperature data and solar radiation data. Accordingly B=: x x Wj and 1/2 (.1302 -f .2688) = .1995 = fc^ = .20. (34) From equations (24) and (25) the new values a\ and a'2 of ax and a2 are and - 3.35 V4+ -3.35 (g5) O.9 Substituting these numerical valuations in equation (22) and deter- mining 03 from the observed surface temperature 21?3 when x equals 0 we have, expressing the angle in degrees M_ (—.318 — .0166*0 cr^y-v [COS (30t — e)— 1] V . 274 + .04 ' | 1T.c (37) V-274 + .04 where tan c=: 2.62 ,W* . (38) g-bl(j/-3) For the surface temperature, put y = 6 and we have , = 5.9 (-.318 -.0166.) _6 _ 72i_5.9(.0166). .DO .DO (39) + 17.95 = — (3.35 + . 175oO cos (30^ — 69)° + 21.30 — .72a;. 348 MISCELLANEOUS STUDIES In the same way the following values of the constants for the latitude interval from 20° N to 30° N were determined : a\ = — .343, o'2=— .0159, a3=— .0161, k.m^ —2.= the latitude gradient = — .41, — .155 = the latitude gradient of the half range, 5.535 .523 m, m, B=- -i and tan e-= -2^-^7^7 = 2.41 I ll-i _ I I {/ Substituting these numerical values in equation (22) gives for the surface temperature 6 = — (3.35 + .155*) cos (30* — 67.5) ° + 21.30 — .41* (40) Observed and theoretical lag of temperature maxima and minima behind the radiation maxima and minima. Comparison of computed and observed normal temperatures. The value of e = 69°, corresponding to the latitude interval 30° N to 40° N, was deduced from theory; and since 30° corresponds to 69 one month, 69° corresponds to —=2.3 months, the theoretical lag oU » ,, ( maximum ) . , ,. , ,, ( maximum ) j. ,• of th-e j minimum f temperature behind the j minimum j radiation. The theoretical time of the maximum temperature is therefore 8.3, or about halfway between August and September; while the theoretical time of the minimum temperature is 2.3, or about halfway between February and March. According to Kriimmel (1907, p. 407) from numerous and extended oceanic observations the average time of the lowest temperature is February (t = 2) and that of the highest is August (t = 8). Again, from the three curves (Makaroff, 1894, pi. 26) giving the mean monthly surface temperature observed in the North Pacific between latitudes 30° N and 45° N the minimum temperature occurred when * = 1.8, 3.0 and 2.5 and the maximum temperature occurred when f = 8.1, 8.3 and 7.8 respectively. The average of the above values of t is 2.4 for the minimum and 8.1 for the maximum. Thus the predicted value of the 349 lag agrees very closely with the observed value. Since this value was computed from that of the period of the temperature change, which is accurately known to be twelve months, and from the foregoing determination of the value of k1ml this agreement between theory and observation affords strong evidence in favor of the reliability of the value .2 adopted for k^m^ which is an important constant in the investigation of ocean currents presented later. From numerous surface temperature observations in the Pacific at long. 173° W, lat. 20° N (Puls, 1895, pis. 1-4), off Madeira in the Atlantic, lat. 32° 30' N (Kriimmel, 1907, p. 407) and off Yokohama and at long. 140° W in the Pacific, lat. 35° N (Kriimmel, 1907, p. 408; Thorade, 1909, pis. 1-3) it was found that the mean annual tempera- tures agreed well with the normal values for the latitude. Therefore there is good reason to suppose that the condition giving rise to the temperatures at these places approximates closely to the normal con- dition. Thus a comparison between the theoretical monthly tempera- tures given by equations (39) and (40) with the observed values will give a still more detailed test of the theory (table 2). TABLE 2 Theoretical and observed normal surface temperatures at a series of latitudes Latitude 20° N 21° 18' N 30°N 32° 30' N 35° N 40°N £ § 2 b 8 1 Observed Difference b 1 *Observed Difference b o O H b o I H Observed Difference b o I J3 H Observed Difference £> 1 1 2 3 4 5 6 7 8 9 10 24 °n 24 °1 + °1 23 °3 21 °6 -1°7 18°7 16°6 18°0 + 1°4 14°4 13°4 -1°0 10°1 23.6 24 0 24.2 24 7 + .6 + 7 22.9 23 3 20.8 21 6 -2.1 -1 7 18.0 18 2 15.7 16 0 17.2 17 1 +1.5 + 1 1 13.6 13 8 13.8 13 4 + .2 - .4 9.1 9.3 24.7 25 6 24.7 24 9 + .0 - 7 24.1 25 ? 22.1 23 0 -2.0 -2 2 19.2 20 8 17.1 18 9 17.9 18 7 +0.8 -0 2 15.1 17 0 14.2 17 ? - .9 + 2 10.9 13.3 26 5 25 9 - 6 26 1 24 4 -1 7 2? 6 20 9 20 3 -0 6 19 2 18 5 - 7 15.9 26 8 26 3 - 5 26 5 25 3 -1 2 23 9 >•> \ 21 8 -0 6 21 0 21 6 + 6 18.1 27 2 26 7 - 5 26 9 25 8 -1 1 24 6 23 2 ?:?: 9 -0 3 21 9 23 5 +1.6 19.1 26 8 26 7 - 1 26 5 25 1 -1.4 24 4 23 1 23 2 +0.1 21 6 2? 7 + 1.1 18.9 26.1 26.4 + .3 25.7 24.4 -1.3 23.3 21.9 22.1 +0.2 20.3 20.0 - .3 17.3 11 25.2 25.8 + .6 24.6 23.0 -1.6 21.6 20.1 20.6 +0.5 18.4 17.2 -1.2 14.9 12 24.3 24.8 + .5 23.7 21.1 -2.6 20.3 18.1 19.0 +0.9 16.2 16.4 + .2 12.3 Mean annual 25.4 25.5 + .1 24.9 23.2 -1.7 21.3 19.5 19.9 +0.4 17.7 17.5 - .2 14.1 values *Air temperatures at Honolulu (Monthly Weather Review, 1903, pp. 225-226). 350 MISCELLANEOUS STUDIES It appeals that the theoretical results agree well with observation. If the difference between the theoretical and observed mean annual temperatures due to the average departure of the local conditions from the normal is applied as a correction to the observed monthly temperatures the agreement between theory and observation is very close. Numerical estimates of the coefficient of absorption of solar radiation in sea water. A lower limit of the value of the absorption coefficient bl can be determined from quantities depending on surface temperatures and the amount of solar radiation at the surface of the ocean by the fol- lowing method. The value of Kl (p. 344) obtained from Angot's data (Hann, 1915, p. 40) was 7f1 = 5.18X 107A where A is the solar constant. The more accurate result of Schmidt's later investigation (1915; p. 121) (p. 345) is Since £ = K 1== 217 X 30 X 10* = 3.255 X 107A. Bml = 5.9 (p. 347) .94X!0X5.95.54 6 g= K But since— is the ratio of the amount of energy supplied to the water v by solar radiation to the amount available at the surface, -=- < 1. Therefore K = 5.54 X 106 = 5.54 Kv ~m1bl X 3.255 X 107A ™ 32.55 wi^A < Using the accepted value 2.00 for A we have mjti = b^er^ > .0851. TABLE 3 fc, 0 .05 .10 .12 .15 .20 .25 .30 be-** 0 .043 .074 .083 .096 .110 .118 .122 351 From the values of Z^e'361 given in table 3 it follows that &t > .12 or e~bl = & < .887 where {S^ equals the proportion of incident light that passes through one meter of sea water. Direct observations of the proportion of solar radiation passing through samples of sea water taken from the Nordlichen Ostsee and the Bottensee (Petersen, 1912, p. 39) give values of & varying from .60 to .86, which are less than the upper limit .887 deduced from theory. The variation with respect to depth of the heat absorbed by the water tends to maintain a temperature gradient which would be greater the smaller the transmission coefficient, and the mixing process tends to reduce the gradient by transferring heat from warm to cooler layers. That is, the rate at which heat is supplied to a given layer is equal to that due to direct absorption of radiation plus the amount due to the alternating vertical circulation of the water. But the rate of gain of heat was assumed in the theory to be due entirely to the absorption of radiation ; and therefore the estimate of the value of the transmission coefficient deduced from observed temperatures at dif- ferent depths would be larger than the true value. This conclusion is confirmed by the following computation, based on temperature observa- tions near San Diego (McEwen, 1916, pi. 26). The general equation (22) (p. 344), is of the form 0 = R1 e-Mv-s) [cos (aj _€)_i] +R2 where Rt and R2 are constants, for a given latitude. Therefore, Tj^g-Ms-a) eqliais the half range of temperature at the surface, Tj^g-Mio-3) equais the half range at the depth of 10 meters and [E1e~&i(6-3) — Rle-bi(10~3')] equals the difference between the mean annual temperature at the surface and at the depth of 10 meters. If there is a vertical flow (p. 374) the general temperature equation reduces to the same form (equation 155, p. 390), and can therefore be applied to temperatures in the San Diego region. Substituting the observed average values of these quantities (McEwen, 1916, pi. 26) gives R^-31'! = 3.15 half range at surf ace (41) Rl6-^ = 2.70 half range at depth of 10 meters (42) Rl[e~a^1 — e~76i]=.40 difference in mean annual tem- perature at surface and at 10 meters. (43) 352 MISCELLANEOUS STUDIES From equations (41) and (42) e«>i = |4?r =1-168 or 6, = .039 fi* I U and flje-36' — e-71*]=R1 (.1285) = A5 or #, = 3.50. From equation (43) and the value, 3.5, already found for R1 e-** — er'r* = •£=• = .1142 and &1 = .034 o.D which agrees approximately with the value .039 obtained from the first equation. The average value .0365 should be used instead of the large value of bl exceeding .12 (p. 351), in order to obtain the actual rate at which the water gains heat as a result of both absorption and mixture of water from other layers. That is, the rate of gain of heat in the actual system takes place as if there were no such mixture of the water and the coefficient of absorption were less than the true value. Hence, as far as the rate of gain and loss of heat is concerned we can substitute this more simple ideal system for the actual one. We have now determined all of the constants of the original differential equation (4), on page 341, which expresses the time rate of change of heat in an element of volume, on the assumption that the average flow, either vertically or horizontally, is zero. The modified tempera- ture resulting from any additional factor, for example a current, can be deduced by solving the above differential equation, to which has been added the rate of change of heat due to this factor. DEDUCTION OF THE CHANGE IN SURFACE TEMPERATURE PRODUCED BY A HORIZONTAL FLOW OF WATER Preliminary discussion. Statement of assumptions and mathematical formulation of the problem. It is well known, as stated by a prominent British hydrographer, Wharton (1894, pp. 699-712), that "the most obvious phenomenon of the ocean is the constant horizontal movement of its surface water, which in many parts takes well defined directions. ' ' The work of both practical seamen and scientists has after many years revealed the essential features of the main ocean currents, and in a few limited regions a fairly detailed knowledge of the currents has been obtained. However, all investigators agree that the esti- OCEAN TEMPEEATUEES 353 mation of the direction and rate of flow of water in the ocean is attended with many difficulties. Some of the methods of making such estimates will now be briefly reviewed. The most direct and widely used method is the comparison of the position of a ship every noon determined from astronomical observa- tion and from the log and course during the previous twenty-four hours. The set of a current estimated in this way is subject to large errors, unless special care is taken in making the observations. Under ordinary conditions such estimates of currents less than ten miles in twenty- four hours are quite uncertain (Kriimmel, 1911, p. 420). Another method of studying currents is to use drift bottles enclos- ing slips of paper on which to enter information as to when and where they were found. A sufficient number of records of the initial and final positions of these bottles and the corresponding time intervals will, under favorable conditions, yield information especially as to the average direction of the surface drift. This method is best adapted to small enclosed seas as the bottles may then be easily recovered soon after reaching the shores. For the open oceans it is not satisfactory. Other floating objects, such as wrecks, icebergs, trees, and plankton also furnish some information about the horizontal circulation. Under favorable conditions the current at a given place can be measured directly by means of a current meter or by observing a floating object designed to move with the current. In the open ocean the difficulty of holding a ship in a reasonably fixed position usually renders these methods impracticable. Investigations of the causes of ocean currents and their relation to these causes provide indirect methods of determining them. Ocean currents are directly due to various external forces, the wind or friction of a neighboring current, differences in pressure resulting from evaporation, precipitation and differences in specific gravity, and are modified by the deflecting force due to the earth's rotation and by internal friction of the water. Thus, any theory of ocean currents capable of yielding even a rough approximation to the quantitative relations between the complex system of causes and the resulting motion of the water would necessarily be highly complicated. As a matter of fact, great difficulties always arise in attempts to establish a connection between practical hydrography and theoretical hydro- dynamics, and deductions of currents from their causes are quite uncertain except in special cases in which the conditions in the ideal 354 MISCELLANEOUS STUDIES problem agree well with those in nature. The application of theory to practical problems is rendered especially difficult, first, because of lack of knowledge of the frictional resistance to the motion of sea water, and, second, because of the uncertainty regarding the current produced by a wind of given velocity and direction. One of the most important needs now is a comprehensive pro- gramme of observations at sea, of the currents themselves and their causes, supplemented by attempts to formulate hydrodynamical prob- lems whose solution shall be consistent with the observations. .Much credit is due to the pioneer investigators, Zoppritz, Mohn, Bjerknes, Sandstrom, Ekman, Jacobsen, and others, for their development of methods of dealing with such problems. Another important aid to the determination of oceanic circulation is found in the fact that a current consists of water particles tending to preserve their temperature and salinity as they move along. Tln-s.- characters change slowly and thus serve to depict the currents some- what as do floating objects that are readily identified. This part of the paper presents an attempt to develop, along the line suggested in the following translation from Krummel (1911, p. 439), a method of deducing currents from the temperature dis- tribution : No simple rule has been formulated for determining currents from tempera- ture charts. But it is conceivable if not certain that a systematic investigation of the so-called individual temperature changes will give a reliable basis for the estimation of currents from temperatures. (We must distinguish between the annual temperature range, corresponding to definite geographical positions, and the practically uninvestigated temperature changes which one and the same water particle undergoes along the great horizontal current systems. In a continuous current, for example, the Gulf Stream, these individual temperature changes which must be distinguished from changes at a given position may run through the whole range from tropical heat to the freezing point.) The problem is, however, very difficult, and a cursory comparison of the current charts in the Atlantic as prepared from the Log Book of the "Seewarte" reveals the great complexity of these closely inter-related phenomena. In general, in connection with all water motions time is an all important factor. Rapid and slow currents behave very differently as regards their heat content, and can therefore give rise to widely different types of isotherms. Xo constant angle between stream lines and isotherms can be proposed; the angle can vary between 0° and 90°. The most frequent case is that of stream lines cutting the isotherms obliquely. In general, the rate of change of heat in an element of volume can be expressed by adding to the right-hand member of the differential equation (3) the rate of change due to other factors not considered on OCEAN TEMPEBATUEES 355 page 339, and the solution of the new equation will give the tem- perature under the new conditions. The rate of change of heat due to a horizontal flow H of the water can be readily derived as follows : consider a rectangular element of volume (fig. 2) of unit length per- pendicular to the direction of flow and of breadth dz measured in the direction of flow and thickness dy normal to the direction of flow. Fig. 2. Then the rate at which heat enters into the element less the rate at which it is removed will be HaOdy — Ha(0 + d6) dy = —HadBdij = —H.«) (69) i Substituting (6'-\-6") inequation (68) gives de" * d0' (70) For & use the normal value determined from the expression j of equation (59) for t = t1 then for surface temperatures using the value 6 for y (see page 343) 60' where tan c =7- k This is consistent with equation (69) since 0X may be any function of z. Equation (70) then becomes Integrating equation (71) gives _ fc(z— zn) a TJ 0" = Oe-^^-1 — -^ (72) where 0 is arbitrary. Adding the two solutions ff and 6" gives _ / ^ , , ^z0) Ba*mn , B cos (a# — e) + - -- h' — i -- rr (73) where the expression j Ms the normal temperature. To deter- mine the temperature at a given position, distant (z — z0) from the initial position z0, give 0. such a value that the expression for 0 in equation (73) will reduce to the given temperature when z = z0. Then substitute this value and the given value of z in equation (73). 362 MISCELLANEOUS STUDIES Consider two parallel stream lines, A and B, the velocity being #A along the first and HB along the second, then the temperature in A for any value of z minus the temperature in B for the same value of z is — Hz — Zo) _ fc(z Zn) a —UB—+y-l(HB—HA)=M (74) (75) Denote HA—HB by AH, then fc(z — z«) _ *r(z — Also if -^— is small we have approximately ? _ 9 \ 1 -^ (76) THE RATE OF HORIZONTAL FLOW IN THE NORTH PACIFIC OFF THE CALIFORNIA COAST FROM LAT. 40° N TO 30° N AND IN THE NORTH ATLANTIC OFF THE WEST COAST OF AFRICA FROM LAT. 30° N TO 20° N. The rate of flow deduced from surface temperatures. From the hydrographic charts (Thorade, 1909) of the region of the Pacific off North America, it appears that that the average direc- tion of the surface drift from Cape Mendocino, Lat. 40° N, does not at any season differ greatly from a straight line determined by the points, Lat. 40° N, Long. 124° W, and Lat. 30° N, Long. 126° W. Assuming that there is a surface drift in this constant average direc- tion which is proportional to the average wind velocity over this course, will some numerical value of the drift account for the monthly temperatures at the down-stream end of the line? From the monthly isotherms worked out by Thorade (1909), the observed mean monthly temperatures at any point of the region can be found. From these observed monthly temperatures at the upper end of the line and a mean value of the drift velocity determined by trial, the temperatures at the down-stream end will be computed according to the theory on page 359. A comparison of these theoretical tempera- tures with the observed ones and of this theoretical value of the drift with estimates made in other ways will indicate the practical value of the theory. The observed temperatures taken from Thorade 's chart (1909), and the numerical values of the other quantities computed Month = i Observed temp Normal temper 0" (from equat k - (a^ cos at' — 05 sin C' Ct *t'— -4 Normal temper tf + B" (i — •— cosa# 4-- (* --- ^ ^' 4. ^" _j_ ^'" Observed temp Computed min * These two lin OCEAN TEMPERATURES 363 from the theory (pp. 355-360) are condensed in table 4, in which the following values of the constants are used: «4 = 0, a5 = — .6, <*! = — .318, a3 = — .0244, a2 = — .0166, k —.20, and H = — 1.2 (1 — .6 cos 30° £) equals the drift, in degrees per month equals 1.0 to 3.8 miles in twenty-four hours. The mean wind velocity in miles per hour over the course considered (Moore, 1908-11) is approximately — .6 cos The rate of flow deduced from temperature data compared with that expected from the empirical relation of winds to currents and with direct observations on currents. As stated by Helland-Hansen in his paper on physical oceanography (Murray and Hjort, 1912, p. 247) : The wind may produce a current, particularly in the surface layers, thus altering the direction and velocity of the existing current. We know very little, however, about the relation between wind and current, through lack of detailed observations, although the question is naturally of the first importance from an oceanographical point of view, as well as from its bearings on the conditions of everyday life. This is one of the principal tasks for the ocean- ographer of the future; such observations are difficult to make, no doubt, but with modern methods much can be done. However, numerous observations of winds and currents have been made. And, although the relation of wind and current varies with the wind velocity, the latitude, coast line, depth, and distribution of specific gravity, some progress has been made in estimating the drift that a given wind velocity will produce. A careful investigation of this question based on Ekman's theory (1905, 1906) and a large mass of available data made by Thorade (1914) yielded the following results. In case the coast is sufficiently distant and the effect of the pressure gradient due to differences in specific gravity is small, the drift will be directed at an angle of 45° to the right of the wind direction in the northern hemisphere. The relation of the drift to the wind velocity estimated by Thorade (1914, p. 387) is , (77) Vsin sec. hour and (78) , .. Vsin<£ sec. hour where V is the wind velocity, H is the current in meters per second, and is the latitude. 364 MISCELLANEOUS STUDIES The mean latitude of the drift computed from temperature data (p. 362) is 35° and its direction was 45° to the right of the mean wind velocity in accordance with Ekman's theory (1906) and Thorade's estimate from observations (1914). From equation (78) and the observed value of V (p. 363) the drift would be 3.9 miles in twenty- four hours if it were due entirely to the observed winds, uninfluenced by the coast and differences in specific gravity. This estimate is of the same order as 2.4, that made from temperature observations (p. 363). Again, direct observations of the drift having a southerly component (Thorade, 1914, p. 283) near the head of the stream, Lat. 40° N to 50° N, gave the values presented in table 5. TABLE 5 Observed surface drift, and values computed from temperature data Month 4 5 10 Mean Observed drift in 24 hours 3.69 2.05 2.41 2.6 No. of observations 21 24 54 Computed drift in 24 hours.... 3.12 3.65 1.68 2.8 Thus the theoretical drift estimated from temperature data agrees as well with the observations as could be expected. And it appears from the comparisons made that estimates of the drift from tempera- ture data will prove to be as reliable as those made by other methods. The surface current during a short time interval near the northwest coast of Africa, estimated from surface temperatures, and com- pared with direct observations) and with results deduced from the empirically ascertained relation of winds to currents. From a series of direct measurements by means of a float designed especially for the purpose (Schott ei al., 1914), the average flow between latitudes 20° N and 28° N, off the west coast of Africa, was found to be nearly parallel to the coast and toward the southwest. These current measurements were accompanied by observations of surface temperatures and winds, and the stations were distributed along a line nearly parallel to the average surface drift and about 150 miles offshore. All of the observations were made during the OCEAN TEMPERATURES 365 short time interval from June 2 to June 15, 1911, and are therefore appropriate for the application of the theory developed on pages 360- 362 for estimating surface currents from temperatures. The mean position during the three days, June 2, 3, and 12, was Lat 30° N, Long. 14?6 W, and that during the three days, June 13, 14, and 15, was Lat. 24° N, Long. 17? 3 W. The distance between these positions is 6.74, the unit being a degree of latitude, and the mean surface temperatures were respectively 18? 32 and 19? 12, each value being the average of eighteen observations. In equation (73), page 361, (z — 20) is the distance, measured in degrees of latitude in the direction of the drift, and the initial position is in this case at Lat. 30° N. The direction of the drift was found to be to the south at an angle of about 27° to the right (west) of the meridian, therefore the change in latitude corresponding to the distance (z — 20) along the line of the flow is (cos 27°) (z — £0) = .891 (z — 20). From these values and the numerical values of the constants given on page 346, equation (73) becomes _ - .217(2 - Zn) 0 = 22.6— (.891) (.41) (z — z^+Be -- nl -- +(.891) (1.88JTJ which gives the temperature at any point along the stream line, the mean velocity being Hl degrees per month. To determine Ht substitute the two mean temperatures with the corresponding values of (z — ZQ), thus obtaining two equations 18.32 = - 22.6 +"0 + 1.685J3'1 and . 1.461 19.12 = 22.6 + (.365) (6.74) + Oe~nT+ 1.685H, Eliminating 6 gives the equation 1.461 -(4.28 + 1.6857IJ e~ST-\- 1.6S5H, = —5.94 from which the value of Hlt found by trial is Hl = — 9.4 degrees per month = — .78 miles per hour. Using this value of Hl the theoretical temperature at any point along the stream line is 0 = 6.75 — .365(2 — *0) + 11.57e-°231<*~fo) where (z — 20) is negative since the latitude decreases in the down- stream direction. 366 MISCELLANEOUS STUDIES Direct estimates of the drift were made at six stations along this line from angular measurements relative to a float, the ship being manoeuvered in such a way as to keep the sounding cable as nearly vertical as possible. The values obtained at each station in the order from north to south are 1.0, 0.7, 0.9, 0.8, 0.9, 1.3 miles per hour in a southwesterly direction. Each value is the mean of about twenty-five Fig. 3. Geometrical construction for determining the effect of a coast on the surface current produced by wind. observations. The components parallel to a line from the first to the last station having the mean direction of the observed drift are 0.99, 0.7, 0.9, 0.7, 0.86, and 1.11 miles per hour, and the mean value is 0.88. From the four estimates based on "dead reckoning" and the position of the ship determined from astronomical observations at noon, the drift appeared to be directed to the west of the direction determined by the "float" method. The values are 0.4, 0.5, 0.4, 0.4 and the components parallel to the mean direction of the drift found by the float method are 0.3, 0.2, 0.16, 0.19, the mean value is 0.21. The wind blew steadily from the northeast, the observed velocities in miles per hour being 28, 23, 28, 34, 3, 18, 13, 28, 28, 28, 34, and 34 ; the mean is 25. From equation (78), page 363, using 24°, the mean latitude of the stream line for , the drift due to a wind velocity of V miles per hour would be .01975F miles per hour. Using the value 25 for V the un- OCEAN TEMPEEATUSES 367 disturbed drift due to the wind would be 0.494 directed at an angle of 45° to the right of the wind direction; this direction of drift is nearly the same as that obtained from dead reckoning. If the same wind velocity prevailed over the whole coastal belt, a correction to the above estimate of the drift must be made (Ekman, 1906, p. 23). The computation can be carried out graphically as follows (fig. 3). Let OT be the direction of the wind, and OA represent in magnitude and direction the "undisturbed drift" computed from equation (78). If a circle is described through A tangent to OT, and a line AD is drawn parallel to the coast then OD will represent in magnitude and direction the corrected surface drift. In the case under consideration the corrected estimate OD is twice the value of OA and makes an angle of about 27° to the right (west) of the observed mean direction. Therefore the component parallel to this observed direction is (OD) cos 27° = 0.89(0Z>) = (0.89)2(0^4) = 1.78(0^4), The results corresponding to various values of the wind (V) are presented in the following list. F OA OD (OD) cos 27 13 .257 .51 .46 18 .356 .71 .63 25 .494 .99 .88 34 .672 1.34 1.20 Finally it is evident that the velocity of 0.78 miles per hour deduced from surface temperatures agrees well with the estimates made by the other methods. THE RELATION OF TEMPERATURE TO TIME, DEPTH AND RATE OP VERTICAL FLOW IN THE INTERVAL FROM 40 TO 600 METERS Statement of assumptions and mathematical formulation of the problem. It has been found (p. 351) that the direct heating of the sea water by the absorption of solar radiation is proportional to e~^v where bl > .12 and y is the depth in meters. Hence at the depth exceeding 40 meters this direct heating effect would be less than 1 per cent of that at the surface. Also the temperature range at that depth would bear the same proportion to that at the surface if the variation in rate of gain of heat were due only to the variation in this rate of absorption. 368 MISCELLANEOUS STUDIES However, observation shows that there is a seasonal variation of 5° at 40 meters and exceeding 1° at 100 meters (Murray, 1898, p. 127; McEwen, 1916, p. 268) ; thus something other than the direct absorp- tion of solar radiation must be the main factor in heating the water of these lower levels. These facts show that there must be a transfer of heat between the upper and lower level, but the ordinary process of heat conduc- tivity, as illustrated by laboratory experiments on still water, is wholly inadequate to effect this transfer at a sufficiently rapid rate (Wegemann, 1905l*) — wlal] ± [(2alAi2— wO&Ji (85) 370 MISCELLANEOUS STUDIES and, if the solution is to be a periodic function of the time having the period — where 04 is positive «i I^(al2 — blz) — wla1 = 0 (86) (2a1^ — w1)b1 = a1 (87) Solving equation (86) for al and equation (87) for bt we have «/! ;+: v Wl " • ^7* "\ /QQN «i= jri and 7. - al Since the temperature and the amplitude of the temperature decrease as the depth increases, the exponent a^y and hence al must be negative (y is positive in the direction from the upper surface downward). Therefore only the negative sign is admissible before the radical in equation (88) and is definitely determined by given values of u\, ft2 and ±bl. Solving equation (87) for aa gives therefore because of equation (90) 01Lai must be negative, or &t - must be negative since ax is assumed to be positive. From equations (90) and (91) we have «1»=61X»+ VV (92) and where only the plus sign is admissible since &^ is necessarily positive. Substituting this value of fe^ in equation (90) gives a _ i V OCEAN IEMFESATVBE8 371 substituting this value of a^ in equation (89) gives &i = !L-== (95) 2 which agrees with the result already found on page 370, that -^ PI must be negative. From pages 369 and 370, 0—Meav+™, where a — aizt&i* and b = ± a1= ± (2alfj.2 — wjb^ The solution of equation (81) is therefore 0 = j|fe«iv ± (fciiH-aie)i (96) where M and at are arbitrary constants, a: and &! are given by equa- tions (94) and (95) and the same value of ax is to be used with either the plus or the minus sign before the expression in brackets. From the properties of imaginary exponents equation (96) can be put in the real periodic form $=0*»{Almn(l>l-y + D ;(104) where C and D are arbitrary constants. This expression for 0 can be added to the right-hand member of equation (98), giving the more general solution (105) Solution for the case in which the vertical flow is a periodic function of the time. If the vertical velocity has the value w^=w1 [1 + rcos a£] the general equation (80) becomes — = 2— — w [I-1 J"66 Let (108) (109) and substitute in equation (106), the result is df(t] 2fl2 ^ _ dt from which a where c is an arbitrary constant. OCEAN TEMPEEATUEES 373 Let a = a1±~b-Li or a? = a^ — &X2± 2a1&1i (HO) then — Oi^iT «W]t — ^sinat (HI) the arbitrary constant of equation (109) being so chosen, that when r equals zero, equation (111) reduces to equation (82) derived for a constant velocity. Rearranging the terms in the exponent of e in equation (111) gives (112) Let I>1(2fjiza1 — w1)=a1 (113) and 2/2 7i 2 \ /» * A / "1 "1 A \ as before (p. 370). Substituting in equation (112) and making use of the properties of imaginary exponents gives 0 = M e °iy± ailj/t =*= sin at -sin at (aj + 6^ — ^^sin a#) I + B cos [ajt + b,y — i^-sin at) Y (115) where at and &, have the values given on page 370 and Alt Bl and al are arbitrary. The values 6t = ax = 0 and al = 0 or A are also consistent with equations (113) and (114) and lead to the solution D — c(l — e-~^r- IT where C and Z> are arbitrary constants and \ has the value — ' 374 MISCELLANEOUS STUDIES The differential equation being linear, this solution can be added to the right-hand member of equation (115) giving the solution + «--^.'n at | Al Sin fa,* + blV -^shl at~] •4-BjCOB ajf-f-ftjl/ -- — — sinaf D fa^ + ftaj/ — ii^- si cosa^ + ftaj/ — i- sin af (116) which reduces to equation (105) corresponding to a constant velocity (W T \ —sin at 1 is small equation (116) can be transformed into the following approximate form, retaining only the first powers of the small quantities. 2a (cos (a — aj — btg) — cos (a + a^ + ^y) J — (B^ ( sin (o + a^ + b,y) + sin (a — a^ — &,?/) J | (117) Numerical values of the constants in the solution, determined from temperature observations in the Pacific near San Diego. It is well known that the waters of certain inshore regions, includ- ing that off the west coast of North America, have a temperature significantly below the normal for the latitude. Various explanations of this phenomena off the California coast have been offered, but (Holway, 1905, and McEwen, 1912, 1914, 1916) the only one so far proposed that is consistent with all of the known facts is that of an upward flow of cold water from lower levels. OCEAN TEMPEKATUEES 375 Assuming this upward flow to be the only cause of the temperature reduction, the theory developed on pages 372-374 will now be applied to the series of temperature observations made off the Coronado Island about twenty miles from San Diego (McEwen, 1916, pp. 267, 268 and pi. 26). It follows from Ekman's theory (p. 401) that the vertical velocity off the California coast is proportional to the component of the wind velocity parallel to the coast, and decreases in magnitude as the distance from the coast increases. For this reason the velocity estimated from the temperature data mentioned above will be less than that nearer the coast. TABLE 6 Average of observed and computed monthly temperatures off San Diego at a series of depths. Month 1 2 3 4 5 6 7 ' 8 9 10 11 19 mean Depth in meters o 15 0 14 3 14 6 15 9 16 1 17 8 IP 7 90 6 90 ? 18 8 16 8 15 5 17 0 0 C o 15 0 14 6 14 5 14 7 15 4 16 6 18 9 IP 5 IP P 18 8 16 8 15 4 16 6 10 C o 14 9 14 9 14 0 13 6 13 0 14 9 15 0 16 0 18 ? IP 0 16 9 15 0 15 2 20 C O 13 8 13 8 13 5 19 6 11 0 19 ? 13 0 14 0 17 8 18 0 15 8 14 5 14.2 30 C O 13 4 13 4 13 0 11 0 10 5 10 8 11 8 12 7 14 8 16 8 15 4 14 0 13.1 40 C o 13.4 13 1 11.9 13 0 10.6 19 3 9.9 10 5 9.9 10 0 10.6 10 5 11.9 11 0 13.4 1? 0 14.7 13 6 15.5 15 0 15.5 15 1 14.7 13 5 12 5 50 C 13 9 11 P 10 6 P 8 P 8 10 4 11 6 19 P 14 ? 14 P 15 0 14 4 o 1? 8 1? 6 11 7 10 0 P P 10 9 10 7 11 0 19 8 14 3 14 7 13 9 12 0 60 C O 70 C o 13.1 12.4 12.9 1? 0 11.8 12.1 11.7 11 7 10.6 11.0 10.6 10 7 9.9 9.9 9.8 p 8 9.7 9.8 9.6 P 7 10.2 10.0 10.0 P 8 11.2 10.5 10.9 10 3 12.5 10.8 12.0 10 7 13.7 12.2 13.2 11 8 14.4 13.8 13.9 13 0 14.6 14.1 14.2 13 7 14.1 12.9 13.8 19 7 11.6 11 3 80 C O 12.7 11 7 11.6 11 3 10.6 10 3 9.8 P 6 9.5 P 6 9.8 P 8 10.6 10 ?, 11.6 10 5 12.7 11 ?, 13.5 1? 8 13.7 13 9 13.4 19 3 11.0 90 C o 12.5 11 3 11.5 11 0 10.5 10 0 9.8 P 5 9.5 P 5 9.7 P 7 10.3 10 0 11.3 10 3 12.3 11 0 13.0 19 4 13.3 19 8 13.1 11 P 10 8 100 C 1? 9 11 4 10 4 P 7 P 4 P 5 10 1 10 P 11 P 19 6 13 0 19 8 0 150 C o 10.3 11.2 P 5 9.9 10.7 P 0 9.2 10.0 8 8 9.0 9.4 8 7 9.0 9.0 8 8 9.2 8.9 8 P 9.5 9.1 P 1 9.8 9.6 P 4 10.2 10.2 P 7 10.9 10.9 10 9 11.0 11.3 10 4 10.7 11.4 10 0 9.9 9 4 200 C o 10.1 8 4 9.9 8 1 9.5 8 3 9.1 8 9 8.7 8 9 8.5 8 9 8.5 8 4 8.7 8 7 9.1 P 0 9.6 P 4 10.0 P 4 10.2 8 7 8.6 300 C O 8.5 7 8 8.5 7 7 8.4 7 6 8.2 7 5 8.0 7 6 7.8 7 6 7.7 7 7 7.7 7 8 7.8 8 0 8.0 8 4 80 .« 8 4 8.4 7 8 7.8 400 C 7 4 7 5 7 5 7 5 7 4 7 9 7 1 7 0 7 0 7 1 7 9 7 3 o 7.0 500 C 6 8 6 8 6 8 6 8 6 7 6 7 6 7 6 6 6 6 6 6 6 7 6 7 376 MISCELLANEOUS STUDIES From table 6, which gives the observed temperature averages at different depths and months, the constants of equation (116) or the simpler approximate form equation (117) will now be determined. The mean annual temperature 6m is given by the first two terms }-D = em (iis) (119) which can be put in the linear form e (em — Z>)= Log e€ + \y. Assuming different values of D, plotting the results, and selecting the value of D, for which the points fell most nearly on a straight line, resulted in the following values of the constants: = 5.6, 0 = 8.3, X = —.004 or (120) where y is the depth in meters. The satisfactory agreement between the computed and observed values of 0m, shown by table 7, proves that the form of the function deduced from theory differs but little from the true form. TABLE 7 Computed and observed mean annual temperatures at a series of depths from 40 to 700 meters Depth 40 50 60 70 80 90 100 150 200 300 400 500 600 700 Om computed @m observed 12?7 13 1 12?4 1? *i 12?1 1?! 0 11?9 11 6 11?6 11 3 11?4 11 0 11?2 10 8 10?2 Q 9 9?3 P 4 8?1 8 6 7?3 7 8 6? 7 7 0 6?4 6 3 6°0 5 5 Difference.... -.4 -.1 + .1 + .3 + .3 + .4 + .4 + .3 -.1 -.5 -.5 -.3 + .1 + .5 The time of minimum wind velocity is in December, that of the maximum is in July (McEwen, 1912, p. 265), and the magnitude of the wind velocity, and therefore the vertical velocity of the water, is approximately proportional to 1 -|- r cos - where t = 12 corre- sponds to the time halfway between June and July and r = 0.2. Also since, as shown by table 6, the temperatures have the same period as the wind, ai = a = ^ in equation (117). In order to determine o the remaining constants substract from the observed temperature for OCEAN TEMPEEATVEES 377 each month and depth the observed mean annual temperature for that depth. Then subtract the expression -C from each of these values using a provisional value of wt. Then fit MeaiV cos (at -f- b^ — e') the equivalent of the expression e*>* ] Aj_ sin (at -f 6^)+ B1 cos (at -f b^y) 1 (p. 374) to these remainders, thus determining M, e, ax and &x. The last part of equation (117) is neglected at first and its value estimated later. Assuming w^ to be — 31 — r- the expression - C ^£ (sin at} e^y becomes — .38 (sin -^ \ e-004" . The following formulae corresponding to the special case when a = ax = — are useful in determining a1? 61} Wj. and /u,2, and follow W from equations (89, 91. 94 and 95) remembering that \== — \ V? .741 .524 .524 V" (121) .2619 .524 ^T; rt = 2^ri (123) n ax can readily be determined from the rate at which the annual range varies with the depth. A was determined from the mean annual temperature at different depths. These values substituted in equation (122) give /*261 from which /** and bt can be found by substituting in equations (123) and (122), and finally the product A^2 gives the velocity wr* * If X and 6, are given, the following equations derived from equations 90 and 95 can be used for computing the remaining quantities: — \o, 378 MISCELLANEOUS STUDIES The constants obtained in this way are listed below: A = —.004, 0! = — .008, M2 = 7760, bt = — .00560, Wl = — month Ax=— -J~^=— .0058, M = 4AO, *'= —61°. f" * 12 Assuming £ = 1 for January, and using the same origin for determining the time in the expression for wind velocities, the expres- sion for the temperature becomes 6 = 5.6 + 8.3e-004" + 4Ae-«08« cos (30* — .32t/ + 61) ° -,38e--004!'cos(30/4-75)0 (124) remembering that C = 8.3 and D = 5.6 (p. 376). The value of p2 = 7760, when expressed in c. g. s. units is (100)2 7760 30X24X3600 = which is about 25,000 times the laboratory value (Wegemann, 1905a, p. 139). But this quantity /*2 is the same as the Mischungsintensitat (Jacobsen, 1913, p. 71), which is a measure of the rate of transfer of salts, heat, or other properties of sea water arising from the mixing of water particles in the alternating circulation (p. 368). Suppose the diffusion of salts and the molecular conductivity of heat to be negligible in comparison to the rate of transfer due to the alternating or reciprocal changes in the positions of the water particles: then as Jacobsen (1913, p. 71) says, the value of this coefficient, the Mischungs- intensitat, determined from any of the properties should be the same under the same conditions. He found values ranging from 1.9 to 3.8 from observations on currents and the distribution of salinities in the sea near Denmark. From observations on tidal currents and salinities in a neighboring region he obtained the values ranging from 0.3 to 11.4. The value 30 obtained from temperatures in the San Diego region is of the some order of magnitude, but the intensity of the circulation in the two regions would probably be different, hence the coefficients would be expected to differ. The idea regarding the alternating motion of water in the ocean held by Kriimmel and Ruppin (1905, p. 36) may be summarized as follows : The coefficient of viscosity determined from laboratory experi- ments, in which the motion of the water is slow and takes place along OCEAN TEMPERATURES 379 parallel surfaces, varies from .008 to .02 for a wide range of tempera- tures and salinities. But the idea of laminar flow no longer holds when one considers the motion of whole volumes of water, hundreds of meters in thickness, throughout which there is a pressure gradient, as is often the case in oceanographic problems. In such cases one should not use innere Reibung (viscosity), but Massenwiderstand (hydraulic friction). The character of the motion is no longer simply laminar (one of simple 'sliding to and fro, parallel to a given plane) but the particles of fluid leave their surfaces and move in vortices along stream lines transverse to the laminar motion. Thus a much greater resistance is developed. For example, the values of the coefficient of viscosity obtained by Nansen in his ocean researches are 200 to 40,000 times the laboratory value. The same general idea has been successfully applied to certain meteorological problems relative to wind, temperature, and humidity by G. I. Taylor (1915). He found that the transfer, in a vertical direction, of heat and water vapor in the atmosphere followed the law of heat conductivity in solids, and that the effect of friction on the motion of the air could be taken into account by substituting in the general equations of motion a quantity called "eddy viscosity" for the laboratory value of the coefficient of viscosity. From the observed relation of air temperature to height off the coast of Labrador, he obtained values of the coefficient; of ''eddy conductivity" from .57 X 103 to 3.4 X 103, corresponding to wind velocities varying from 2 to 3.4 Beaufort. Also from observations on the relation of wind velocity and direction to height he obtained values of the coefficient of eddy viscosity varying from .77 X 103 to 6.9 X 103. The values of these coefficients are more than 10,000 times the labora- tory values, the ratio being of the same order of magnitude as that obtained for sea water. In general, comparisons of his theoretical results with observations indicated a very satisfactory agreement. An especially good agree- ment was found between the predicted and the observed values of the angle between the wind and the horizontal pressure gradient at different levels. 380 MISCELLANEOUS STUDIES JULY 350 Meters I I 300 350 Meters 350 Meters Figs. 4, 5, 6, 7, 8, and 9. Curves showing the theoretical relation of ocean temperatures to depth in a region approximately eight miles west of the Coronado Islands. The crosses ( + ) correspond to observed temperatures. OCEAN TEMPERATURES 381 OCTOBER 50 100 150 2CO fiO 300 100 350 150 200 400 Meters 250 300 350 Meters NOVEMBER 150 200 400 Meters 300 350 Meters DECEMBER 300 350 Meters Figs. 10, 11, 12, 13, 14, and 15. Curves showing the theoretical relation of ocean temperatures to depth in a region approximately eight miles west of the Coronadp Islands. The crosses ( + ) correspond to observed temperatures. 382 MISCELLANEOUS STUDIES Comparison of theoretical and observed monthly temperatures at depths from 40 to 600 meters in the San Diego region. The values computed from equation (124) and entered under the observed temperatures given in table 6 are seen to agree well with the mean of the observed values, thus proving the approximate correctness of the form of the function deduced from theory. These computed values and those from table 12 for the surface are also shown graph- ically by figures 4 to 15, on which are entered a number of points corresponding to actual observations (Michael and McEwen, 1915, 1916). Solution of the problem of temperature reduction due to upwelling with application relative to the 40 meter level in the San Diego region. In the relation of mean annual temperature to depth D =-- (125) deduced from the differential equation (80), A = -4 equals the velocity divided by the diffusivity, but C and D are constants of integration. From observations of the mean annual temperature at a series of depths these constants can be determined as was done on pages 372 to 376, and they correspond to the particular physical con- ditions under which the observations were made. For the same value of D, the deep water temperature, but a different value of one of the physical conditions, say the velocity w^ what will the temperature <£ be? To answer this question it is necessary to know the relation of each constant to the velocity w^. The relation of A to wl is known and it remains to find the relation of C to u\. In the limiting case in which A = 0, denote the new value of the constants by C", D' and A'; then expanding the exponential gives 1' (126) where B' = C'\r is the constant temperature gradient corresponding to zero vertical velocit. C=-/1(A) (127) A A) (128) where A(0) =/2(0) = 1, since, as A = 0. C = C" and D= D'. OCEAN TEMPERATURES 383 Substituting in equation (125) gives >'/2(A) (129) where the forms of the functions /t(A) and /2(A) are to be deter- mined. At the greatest depth, yl for which the theory is valid, assume the temperature to have the constant value ^ for all values of A. What effect will a vertical velocity have on the temperature above this level? The right-hand members of the equations (126) and (129) are equal for y = y1, since 1 is assumed to be independent of A at that depth, that is, X)=B'y1 + D'+C' (130) A Therefore from equations (129) and (130) ^. (131) Subtracting the general value of given by equation (131) from the particular value ' corresponding to the case of no upwelling given by equation (126) gives 4>'_ + = B'(y — yj— f/1(A)(^_ex,l)=A) = CeMe— — e from which the temperature reduction due to the velocity wl is (133) The approximate temperature reduction deduced by two inde- pendent methods is given by equations (132) and (133), respectively. Equating these two values and using equation (127) gives (134) Solving for the unknown function /t(A) gives A(y — yj y-r f ^il (135) Since A is assumed to be independent of y, the variation of the right-hand member of equation (135) with respect to y is a measure of the error in the two expressions for A<£. Also a comparison of the AC theoretical temperature gradient, £'=: ^--^-- (equation 126), which /i(A) would be expected in case of no upwelling with observations of deep water temperature in such regions affords an additional test of the theory. The following values of the constants of equations (125) and OCEAN TEMPERATURES 385 (133) computed on pages 376 to 378, (7 = 8.3, D = 5.6, \ = — .004, w^ = — 31, y± = 600, — - = .237 and sinh — - = .24 are used in a a table 8, which gives the relation of /\(A) (equation 135) to y. TABLE 8 The variation of /^(X) wni/i respect to y. y ^(y-yi) e*v— e**+ex»smh ( — ) V a / AW 30 2.28 1.009 2.26 40 2.24 0.965 2.32 50 2.20 0.924 2.38 60 2.16 0.885 2.44 70 2.12 0.846 2.51 80 2.08 0.809 2.57 90 2.04 0.744 2.63 100 2.00 0.740 2.70 200 1.60 0.466 3.59 300 1.20 0.282 4.26 400 0.80 0.160 5.00 500 0.40 0.076 5.26 600 0.00 0.022 0.00 700 800 Table 8 shows the variation of f1(\) with respect to depth to be less than 20 per cent in the depth interval from 30 to 100 meters, hence the two methods (equation 134) of estimating A are in good agreement within this interval. The value of A (A.), corresponding to 30 meters, the smallest value of y for which the theory is valid, gives the best estimate of A (A), and hence of 5',, since the variation of /t(A) with respect to y is least for small values of y. Substituting the numerical values gives \c, (136) the mean annual theoretical temperature gradients that would be expected at latitude 32° 30' if there were no up welling and the other conditions remained the same as those prevailing when the observations in the San Diego region were made. The observed temperature gradient at the depth of 600 meters not near shore would be inde- pendent of seasonal variations and would be but little affected by horizontal currents, and is in the depth interval of the observations from which the constants of the theoretical formula for mean annual temperatures were computed. 386 MISCELLANEOUS STUDIES TABLE 9 Vertical temperature gradients in degrees per meter at the depth of 600 meters. Indian Ocean South Atlantic Ocean North Atlantic Ocean Lat. 30° to 35 S Lat. 30° S Lat. 30° N -.004 -.0135 -.0025 -.006 -.0160 -.0080 -.007 -.0160 -.0090 -.0085 -.0165 -.0110 -.0095 -.0210 -.0150 -.0115 -.0260 -.0155 -.0130 -.0160 -.0140 -.0175 North Pacific Ocean Lat. 30° to 35° N -.0075 -.0140 -.0215 -.008 -.0150 -.0215 -.0095 -.0150 -.0220 -.0095 -.0150 -.0235 -.0100 -.0155 -.0245 -.0100 -.0155 -.0250 -.0105 -.0160 -.0260 -.0120 -.0170 -.0290 -.0120 -.0195 -.0305 -.0125 -.0205 -.0315 -.0350 Table 9 shows the observed temperature gradient at the depth of 600 meters and at the approximate latitude 32° 30', corresponding to widely different positions between latitudes 30° S to 35° S and 30° N to 35° N, and their average is probably a good approximation to the normal gradient at 600 meters. The average of the 22 observations in the Indian and Atlantic oceans (Schott, 1902, pp. 158-160) is — .0126 degrees per meter, and the average of the 31 observations in the North Pacific (Makaroff, 1894, pp. 456^64) is —.0179. The theoretical result — .0148 agrees well with these observations. The reduction of the mean annual temperature at a given level y for a given velocity w\ is proportional to CeXv (equation 133). that is, the reduction is proportional to the difference between the tempera- ture at the depth y and the constant D. Therefore the temperature reduction corresponding to a given month is proportional to the differ- ence between the temperature at that time and the same constant D. That is, A4" t — D t — D rio7s »\ T\ — , T\ V -1-0' / OCEAN TEMPERATURES 387 where t is the temperature at the time t, A<^ is the corresponding reduction, m is the mean annual temperature, and A<£ is the reduction of the mean annual temperature. Substituting the numerical values for y equals 40 meters, from page 385, equation (137) reduces to A*t = 13\15566(8-3) ('852) ('24)= (^^) 1-7 = -227^-1.27 (138) Substituting the observed values of t at the depth y equals 40 from table 6 in equation (138) gives the values of A<^ entered in the second line of table 10. TABLE 10 The monthly temperature reduction at the depth of 40 meters near San Diego. t 1 2 3 4 5 6 7 8 9 10 11 12 *+t A<£r 1.75 -.10 1.75 - 27 1.68 — 37 1.23 - 37 1.11 - 27 1.18 - 10 1.41 - 10 1.61 .27 2.09 .37 2.55 .37 2.23 .27 1.91 .10 *4 1 65 1 48 1 31 0 86 0 84 1 08 1 51 1 88 ?. 46 ?, W, ?, 50 2.01 But the vertical velocity is u\ ( 1 -|- .2 cos ^ Y and because of its \WiT variation with respect to time a correction equal to ey^ C ~^~ sin at (equation 116) must be added to these values. The correction for this case is .38e--16 cos (30* + 75)° = .324 cos (30* + 75)° = Ar (last term of equation 124, p. 378), and the values are entered in the third line of table 10. Finally the fourth line gives &t + Ar = A0( the total temperature reduction at the depth y = 40 meters. Computing C from equations (136) and (135) and substituting the result in equation (133) gives the expression (?/ — 600) (—.0148) sinh (w 2 \ 4Qg2J 6 7760 e 7760 — e 7760 4- sinh e 7750 .. \4062 / for the mean annual reduction in temperature at the depth y due to the mean annual velocity of up welling ivl. The values of this ex- pression corresponding to a series of values of n\ (expressed in meters per month are presented in table 11 for the depth y = 40 meters. 388 MISCELLANEOUS STUDIES TABLE 11 Theoretical temperature reduction at the depth of 40 meters corresponding to a series of values of the vertical velocity «;,. wl 0 10 20 30 40 50 60 70 80 90 100 Temperature reduction 0°0 0°38 0°95 1°67 2°48 3°34 4°18 5°00 5°80 6°48 7°07 From plates 24 and 36 (McEwen, 1916), and from an examination of the temperature data (Michael and McEwen, 1915, 1916) it appears that the temperature reduction at the 40 meter level, inshore averages from 2° to 3° more than that ten miles offshore. Also surface tem- peratures as much as 9° below the normal have at times been found close inshore in July or August, when the normal temperature is about 23°, while the reduction of the surface temperature ten miles offshore does not at any time exceed 3?5 (table 12). If, corresponding to a temperature reduction of 1?7 ten miles offshore, the inshore reduction is 1?7 plus 2?5 equals 4?2, the corresponding velocity of upwelling inshore would, from table 11, be about twice as great as that ten miles offshore. DEDUCTION OF THE CHANGE IN SURFACE TEMPERATURES DUE TO A VERTICAL FLOW OF WATER NEAR THE SURFACE Statement of assumptions and mathematical formulation of the problem, and solution for the case in ivhich the flow is constant. The temperature reduction at the 40 meter level due to upwelling applies also to the surface water, but owing to the upwelling in this upper level the surface temperature will be still more reduced. The time rate of change of temperature in the case of no resultant flow given by the differential equation (10) on page 342 plus the term — ti'0 — will be the modified rate due to the vertical flow w0 as on °6y page 354. Hence the new differential equation corresponding to a vertical flow near the surface is dT where k = k^ at + azx) cos a* -f a3x + 1] — — w oy (139) OCEAN TEMPEEATURES 389 In case w0 is constant, assume for the form of the solution 6 = fM tan at + f2(y)eoSat + fs(y)x + ft(y)+6i (140) where ^ is independent of t and x. Substitute this expression in equation (139), thus obtaining the following equations: (sin «0 «/,(*) - k. (cos aO [ -a/, (y) + B ay = 0 (142) =0 (143) (144) in which # is regarded as a constant. In case of no vertical velocity the variation of (6 — Ot) with respect to time is small compared to its mean value, which is independent of the time (p. 344). Therefore, assuming this to be true for the present case, a good approximation would result if the constant part were multiplied by the correct factor fete"6ij/ and the variable part by an average value k. Making this change in equations (141) to (144) we have the much simpler ones (145) (146) (147) From equations (145) and (146) (149) where = k — ^& and tan 60=:^-. 390 MISCELLANEOUS STUDIES From equation (147) /s(y)=^ (150) and from equation (148) --5- equals — b^^-^v which gives (152) where ffz is a constant of integration. Substituting these values in equation (149) gives (153) As on page 343 and since the change in temperature due to upwelling near the surface is due to the gradient—- , only terms involving y should be functions oy of w0. Moreover, as w0 increases indefinitely the temperature at the lower boundary of this upper layer should approach the constant value where 0 — 0' ^ —\ — f Therefore, as on page 344 (155) 7* which reduces to equation (22), (p. 344), when w0 = 0, except that 6.2 takes the place of 0, and the average value of k2 takes the place of [&,e~6l<1'~8)]2. The latter quantities are small compared to a2 and therefore the difference between their values makes but little difference in the result. This difference or error comes from the approximation made in solving the differential equation (139), (p. 388). 6.2 is found by subtracting the temperature reduction due to upwelling at and below the surface (3 meter level) from 03, therefore in case of no OCEAN TEMPEBATUEES 391 upwelling 02 equals 03. A second approximation to the solution of \n equation (139) can be found by substituting for — its value from dy the first approximation. The solution is then reduced to i /a2 +V k - _ . i 7, ~r (156) where tan e., = • 1 i ™J0V1 \n' k ' «2+ (hz)2 If t<;0 = 0, equation (156) is identical with equation (22). Solution for the case in which the flow is a periodic function of the time. If the vertical velocity equals W0[l -f-r COS (at — ej] the -time rate of change of temperature can be obtained from the dif- ferential equation (139) in which the last term is multiplied by The new differential equation is therefore l dy (157) Let & be the solution already found when r = 0, and let 8" be the correction due to r, then 0 = 0'-}- 0", and the result of substituting in equation (157) is dO" ^ 60" . .60' . .60" -^- + A:0"+ w0— + w0r cos (a^ — O — + uy cos (at — ej— = 0 (158) 392 MISCELLANEOUS STUDIES Equation (155), using y instead of (y — 3), gives approximately ff and (159) 66' Substituting this value of - in equation (158) and letting dy 0" = ve-^v results in the ordinary differential equation dv i kv — tt'o&jV — [tt'0rcos (at — ej] ' f_ — [f>na (a£ — e2) — 1] / 2 I ]• 2 — rw^vcos (a* — cj (160) where v is a function of £ only. Let k — ?/'(,&! = fc, and Mz = — — ' 1 _ 2 — then equation (160) can be put in the form )S (at — ej— ^ [COS (2at — e3)-|-COSc4] [ \ -f- rwj)^ cos (at — €x) (161) where e2 4~ ei — c When the vertical velocity is directed upward -uf0 is negative. therefore k2=(k — u?061)> | MJ0&i| and the last term of equation (161) can be neglected in the first approximation, which is v = e-™ | — r¥2 f e *»' [cos (a* — Cl ) —-cos ( 2at — e3 ) — -cos J r« + C I 77- f Fa cos f, -\- A\ sin e,~| . FA'., cose, — a sin €]~| : -^ \ I $+?- - J sin «' + [ -^+7^ Jeos a* r2acosC3+A:2smc3"| ~L 2(4a2+^) JS1 [/>•„ cose, — 2asin€.,~| cose4) /ico\ 2(tf+t.') Jeos ~~2^ [ The arbitrary constant C is 0, since from physical considerations the solution must be a periodic function of the time. Substituting OCEAN TEMPEEATUSES 393 (y — 3) for y in the exponential ve~blV and adding the result to 0 from equation (156) gives the following approximate value of the tem- perature in case the velocity of up welling is w0[l-|-rcos (at — ej] COS (at — £,)— 1 rw0Bb1(al-{- a2 a cos c, -4- fc, sin e, ~| . 2 "2 L \sinat a H-/C2 [A:, cos tj — a sin Cj ~1 a2 I /g ^ "2acosc, -4- fe0 sin to"! . " 2. si T*a J cos e. sc, — 2asinc, ] , COS 2^ e" (163) where tan Co = H-"2-^- +- (164) THEORETICAL REDUCTION OF THE SURFACE TEMPERATURE FOR EACH MONTH IN THE SAN DIEGO REGION, DUE TO UPWELLING ; AND COMPARISON WITH OBSERVATIONS The theoretical relation of ocean temperatures to time and depth developed in pages 368-381 was found to agree well with observations from 40 to 700 meters in the San Diego region. The theory developed in pages 388-393 is valid for only the upper ten meters ; but no satis- factory theory for the intermediate interval from 40 to 10 meters or to the surface has been worked out. Now since the temperature reduc- tion at the surface depends upon the upwelling in all three intervals, it is necessary to estimate the reduction in this intermediate interval for which we have no theory. A method of making this estimate is included in the following plan of computing the theoretical tempera- ture reduction at the surface. 394 MISCELLANEOUS STUDIES An explanation of symbols used in making the computations will be given for reference: ff equals the normal surface temperature. 6 equals the theoretical surface temperature when the effect of upwelling is considered. ~& equals the mean annual normal temperature at the surface. Ob equals the constant temperature at the depth 600. A07 equals the total theoretical reduction of the surface temperature. A0'a equals the theoretical reduction of the temperature at the depth of 3 meters which corresponds to surface conditions (p. 343). A<£' equals the theoretical reduction of the surface temperature due to upwelling in the interval from 3 to 600 meters.. A<£' equals the mean annual temperature reduction at the 3 meter level due to upwelling in the interval from 3 to 600 meters. A<£8 equals the mean annual temperature reduction due to up- welling at the 3 meter level. A0' equals the total theoretical reduction of the mean annual tem- perature at the depth of 3 meters. A^r'3 equals the mean annual temperature reduction due to up well- ing in the interval from 40 to 3 meters. Ai£'40 equals the mean annual temperature reduction due to up- welling in the interval from 600 to 40 meters. Throughout the interval from 100 to 40 meters the temperature reduction increases at a constant rate by the amount .36 (table 8), the velocity is practically constant (=w^), and the mean annual 2 3 temperature gradient is -^r. In the interval from 40 to 3 meters the bO 1 7 Q 1 Q 1 CJ () mean annual gradient is - ' — = ^- (table 6), but the mean o7 01 velocity is approximately = (1 -(- q)v\ where qu\ is the velocity nt £t the depth 3 meters. Assuming provisionally that g = 0.1 (p. 403) the mean velocity in this interval is .55n\. The temperature reduction in any depth interval is proportional to the length of the interval, as was shown to be the case in the interval from 100 to 40 meters, and OCEAN TEMPEBATUBES 395 is proportional to the temperature gradient (p. 386). Therefore if the velocity were the same in the interval from 40 to 3 meters, as at the levels below 40 meters, the following relation would hold .36 ~/2.3\6()~2.3 _ / \ _ _ _ ~ /2.3\ \60 / But using the provisional estimate 0.55^ of the mean velocity in this interval we have Ai//3 = .55 X -61 = .34. Using the principle (p. 386) that for a given velocity the temperature reductions are proportional to the temperature gradients (165) Solving for A<£' gives (/)/ /) A /)' \ " - ^6 — ^" s\ i A~7/\ i-\cc\ - — — =— ) (A<£ ) (166) ff—e*—*ff. ) From page 387, and the value of Ai//3 we have A^'=1.7 + .34= 2.04. From page 347, the normal temperature is 0'=— 3.79 cos (30# — 69) ° + 19.5 (167) therefore -3.79 cos (3Q(-69r 13.2 -A since 0000=6?3 (p. 376). The observed mean annual surface temperature is 17?0 (p. 375) but the normal value less A^' equals (19?5 — 2?04) equals 17?46, which is ?46 higher than the observed value. This indicates that there is a still further temperature reduction of the surface temperature due to upwelling at the 3 meter level. From page 390, 02 = 03 — A^>'; therefore, if A' is added to both members of equation (163) we can replace 02 by 03, and the value of 0 -\- A<£' differs from the normal surface temperature solely because of the upwelling at the 3 meter level. Therefore 6' — (6 -f A<£') equals the temperature reduction A0'8 due to upwelling at this depth. Since only the surface tempera- 396 MISCELLANEOUS STUDIES tures are required k can be put equal to k, then k2 will equal k2. From the value of ff (equation 24) and equation (163) we have for the value of A0'8 = ff — (6 + A<£') __ 1 _ ) _ rw0Bb^(a -f- aga: ) j cos c4 i"a cos ( i ««J-* i , _ _ . — • — - — — ccr\ i i -560 ' (.274 + V) ( f.506 + .259A-,~| . , r.966fc, — .1361 | L .274 + VjSm at + [ .274 + V JC°S at fl.046 cos €s -f k* sin c,"] . _ ^ , ffc, cos c3 — 1.046 sin e3"j 2(1.096 + ft>) " 2(1.096 + *,«) J cos2af I (170) using the following values of the remaining constants : a,^ = — .318, a2= -.0166, Be-3^=5.9,Cl = 195, c = 69, e3=(€l+e2), c4=(e2— ej, r=.2, a =.523, &, = .0365, (pp. 347, 351, 376), k = .2, k2 = .2 — .0365w0, tan e2=T-(p. 394). Assume w0 equals — 3, then K2 A^.= .448 — 3.78 cos (30* — 60) + 3.48 cos (30< — 69) - .113 j 1.58 sin 30* + .441 cos 30* i =.448 —.69 cos 30* — .18 sin 30* (171) The values of the temperatures and their reductions are given in table 12. OCEAN TEMPEBATURES 397 TABLE 12 Normal surface temperatures and temperature reductions in the San Diego region. t= 1 2 3 4 5 6 7 8 9 10 11 12 means 0' 16.55 15.75 15.95 17.11 18.91 20.86 22.45 23.25 23.05 21.89 20.09 18.14 19.50 A0S' -.24 -.06 + .27 + .64 + .96 +1.14 +1.14 + .96 + .63 + .26 -.06 -.24 + .45 A<£' 1.66 1.52 1.50 1.63 1.86 2.15 2.40 2.56 2.58 2.45 2.22 1.93 2.02 *A<£r -.10 -.27 -.37 -.37 -.27 -.10 + .10 + .27 + .37 + .37 + .27 + .10 .00 •A0' 1.32 1.19 1.40 1.90 2.55 3.19 3.64 3.79 3.58 3.08 2.43 1.79 2.47 A0' obs. 1.55 1.35 1.35 1.91 2.81 3.06 2.75 2.65 2.85 3.09 3.29 2.64 2.50 0 comp. 15.23 14.56 14.55 15.21 16.36 17.67 18.81 19.46 19.47 18.81 17.66 16.35 17.03 0 obs. 15.00 14.30 14.60 15.20 16.10 17.80 19.70 20.60 20.20 18.80 16.80 15.50 17.00 Difference + .23 + .26 -.05 + .01 + .26 -.13 -.89 -1.14 -.73 + .01 + .86 + .85 + .03 From line 3, table 10 (p. 387). The agreement between the predicted monthly temperatures and ' the observed averages is very satisfactory. Moreover, from the rela- tion of the vertical velocity to depth deduced from hydrodynamical principles, and shown by table 13, the velocity w0 at the 3 meter level, would be .116^, where w± is the velocity below the 40 meter level. - That is, the value of w0 to be expected from that deduced from deep water temperautres (p. 403) is .116 X ( — 31) equals — 3.6, which agrees well with the value — 3.0 deduced from the surface temperature. DEDUCTIONS KELATIVE TO OCEANIC CIRCULATION IN THE SAN DIEGO •REGION BASED ON EKMAN 's HYDRODYNAMICAL THEORY Zoppritz (1878) obtained some theoretical results relative to oceanic circulation, from the general equations of motion of a viscous fluid, and some of his conclusions have been widely used by oceanographers and geographers ; but a critical examination made in the light of later observations showed that his conclusions do not apply to conditions found in nature. These erroneous conclusions are due to his failure to take into account the deflecting force of the earth's rotation and to his use of the laboratory value of the coefficient of viscosity. The importance of the effect of the earth's rotation on currents in the air and ocean was pointed out long ago by Hadley, Coriolis, and Ferrel ; but with the exception of free currents, that is, currents moving by their own inertia, the deflecting force due to the earth's rotation was thought to be so small that it could be neglected until Bjerknes (1901) first made clear the importance of this deflecting force in the case of forced currents. 398 MISCELLANEOUS STUDIES Ekman (1905) also used the general equations of the motion of a viscous fluid, but included the deflecting force due to the earth's rotation, and used in place of the coefficient of viscosity a constant whose value was estimated by applying his formal solution of the equations to field data. That is, he used a virtual value of the co- efficient of viscosity in order to take into account the effect of the irregular vortex motion which greatly increases the magnitude of the mutual reaction between the adjacent water layers. On the simple assumption that the depth of the region considered is large and the coast is at a sufficiently great distance Ekman (1905, p. 7) deduced the effect of a wind, constant in magnitude and direc- tion, over the whole region. His results for the northern hemisphere are, for the velocity of the water, perpendicular and parallel respec- tively to that of the wind, U' = V0e-™ cos (~ ay\ (172) V = VQe-°y sin fc— ay\ (173) Where V0 is the absolute velocity of the water at the surface y is the depth below the surface and a is a constant. The value of a (Ekman. 1905, p. 6) is n = v* sm is the latitude, p.2 is the virtual coefficient of viscosity, and q is the density of the water. From equations (172) and (173) it follows that the surface water velocity (where y equals zero) makes an angle of 45 degrees to the right of the wind velocity, and the angle increases as y increases. "When y has such a value (denoted by D) that the water velocity has the opposite direction to that of the sur- face, that is, when f (174) the magnitude of the velocity is e~v or .043 times its surface value. D is called the "depth of frictional influence," since the water velocity below that depth produced by a wind over the open ocean is but a small fractoin of that at the surface. From an estimate of the relation between the wind velocity and its tangential pressure and the corre- OCEAN TEMPEBATUBES 399 spending ocean current produced, Ekman (1905, p. 42) concluded that .0127 the surface velocity V0 would be approximately D would have the approximate value meters h and that (175) where h is the wind velocity in meters per second. Thus for a wind velocity of ten miles per hour (5.1 meters per second) and at the Fig. 16. Components of the water velocity U' and V perpendicular and parallel respectively to the wind, and the velocity of Vc in a direction perpen- dicular to the coast. 76X51 latitude 35° D would equal ' = 51 meters, and for a velocity V sin of fifteen miles per hour D would equal 75 meters. Solving equation (174) for fj.2 gives 2 = — in — •°000729 • )D2 IT* 7T* which equals 217 in c. g. s. units, when D equals 7500 cm. and equals 35°. The relation of vertical velocity to depth will now be deduced from the results of Ekman 's theory. Let V make an angle A with the coast (fig. 16) and U' the angle (90-)- A) ° with the coast, then the velocity perpendicular to the coast is, from equations (172) and (173), F'sin A + Z/'sin (90 -f A) = Vc 400 MISCELLANEOUS STUDIES where a velocity directed away from the coast is regarded as positive. That is, Yc="P0e~OI'jcosAcosQ —ay J-f sin Ash:Q -ay\ ( = V0e-a»cos(^ -ay— A) (176) Let z equal the distance perpendicular to the coast, then Vc from equation (176) is the limiting value of the velocity perpendicular to the coast as z increases. Also, adjacent to the coast where z equals zero, the velocity perpendicular to the coast must be zero. Let the velocity perpendicular to the coast at the distance z be given by the equation V=Vcf(z) (177) where /(0)=0 and f(z) =1 as z increases. The removal of water at and near the surface due to a flow away from the coast decreases the pressure at the lower levels, and gives rise to a com- pensating flow of deep water toward the coast. Therefore in a coastal region where the surface water flows away from the coast there is a compensating upward flow of deep water. Denoting the vertical velocity by W, the equation of continuity is dz dy neglecting the variation of the component parallel to the coast. There- fore from equation (177), assuming W = fl(z)f2(y) (179) we have /i(2)W=0 (180) To solve equation (180) let df(z} (181) dz where M is a constant. Then from equation (176) and (180) dy \4 / OCEAN TEMPEEATUEES 401 from which we have f2(y)= —MV0 I e-w cos ( ~ ay — A J dy + Cx 0 j sin A sin a?/ — cos A cos ay [ e-w -f Ox Za ( ) i/y A/o" ' 2°a e"ayc°S (oy + A) +(71 (183) where C^ is the constant of integration which must have the value MV V~2~ - cos A in order that /2(0) may equal zero. From equa- £i(t tions (176, 177, 179, and 181) it follows that the horizontal and vertical components of the velocity are respectively V = f(z)V0e-a»cos( ^ -ay — A) W = — fM \ — — =+ [e-°»coa(-—ay — \}dy \MV0 ( V2« J \4 / ) (184) df(z} ( f /* . \ , cos A ) ~ay cos ( - -^- ay — A ) dy = V V0 e~ay cos (ay -f- A) — cos A f- ^ u,z Since the horizontal velocity of the surface water is proportional to the wind velocity (pp. 363, 398) it follows from equation (185) that the vertical velocity of the water is also proportional to the wind velocity. The differential equation of a stream line is in general -^-equals (JLZ w the slope of the curve equals — equals ( f I" * Y* cosA )d/(z) — •{ / e~ay cos ( ay — A }dy V —5 — dy ( J \4 / V2a ) dz ._„(_._ (*_ _ay_A[f(2) (186) which can be reduced to the exact differential equation df(z) /(*) " whose solution is e~av cos f ^ — ay — A J dy j fe-»vcos(-— ay — \\dy- ^4=1 (187) [cos A — e-** cos (ay -{- \)]f(z)= C2 (188) 402 MISCELLANEOUS STUDIES where C2 is a constant of integration corresponding to a given stream line. From equation (185) the upward flux through a horizontal area of unit width and length z measured perpendicularly to the coast is rWdz=—^ Jo [cos A — e"aycos (az -f -, u \~, i ngo) Rembering that /(O) =0 and /(«)=! as z = \ I/O 0[cosA — e-^cos (ay + A)]/(«) •jy^2__ L ^^_vv> (190) and that the maximum numerical value for a given value of y is I Wdz = -V« [C°S A ~ e'"V e™ (191) which approaches the value - ( ^) as V increases, the ratio R of the upward flux through a horizontal area at the depth y of unit width and length z measured perpendicularly to the coast to the total upward flux is I J Wdz [cosA — V cos A cos A Therefore the parameter C2 in the equation of the stream line (equa- tion 188) equals the ratio R multiplied by cos A, and the flux between any two adjacent stream lines of a series in which the increments of C2 are equal is constant. The mean wrind velocity of the 5 degrees square of the U. S. Coast Pilot Charts (Moore, 1908-11) west of San Diego was found to be about fifteen miles per hour in a southeasterly direction, approxi- mately parallel to the coast. Therefore for the San Diego region the angle A in equation (185) is zero, and the vertical velocity at the depth y is, from equation (185), proportional to [1 — e-"vcosay] where a= ^ = ^ (p. 398). The values of this function are tabu- D 75 lated with respect to depth in table 13. OCEAN TEMPEBATUEES 403 TABLE 13 Tabulation of the function I ^ _ \ - 75 CQS 75 y Z?L Try l-e-75 cos=| I y I*. 7TW l_g-75 COS=f- 75 0 0 18 .658 i .043 19 .685 2 .085 20 .710 3 .116 21 .737 4 .166 22 .760 5 .207 23 .783 6 .246 24 .805 7 .288 25 .825 8 .325 30 .913 9 .361 35 .977 10 .399 40 1.02 11 .436 50 1.067 12 .471 60 1.065 13 .515 70 1.052 14 .535 80 1.034 15 .568 90 1.019 16 .600 100 1.007 17 .630 infinity 1.000 The relation of the velocity to depth was deduced from hydro- dynamical considerations, but its relation to distance from the coast, which requires the determination of the function f(z) (equation 177, p. 400), did not result from the foregoing reasoning, but will now be considered. From equation (177), page 400 /(0)=:0 and f(z)= 1 as z increases, and for large values of y off San Diego, equation (185) becomes T7 ,7JV~\ (193) ay 2 dz where (pp. 377, 388) W1 = — 31 meters per month where z equals 10 miles, and equals double that value or 62 meters per month, where z equals zero. From page 363, for an average wind velocity of 15 miles per hour or 7.5 meters per second .0126 X 7.5 Vsin 35° = .125 meters per second 404 MISCELLANEOUS STUDIES equals 324,000 meters per month and a equals — (p. 402). Substi- 75 tuting these numerical values in equation (193) and expressing z in miles gives df(z) =.Q2W for 3 = 0, dz and df(z) = .0105 for 0 = 10. (194) While these conditions, which f(z) and , must satisfy, do not dz determine the functions precisely, they suffice for a rough estimate. The following form f(z) = 1 _ kj-te — (1 — kje-*** (195) has the value zero when z equals zero and approaches 1 as z increases indefinitely for all positive values are of /^ and h2, and differentiating with respect to z (196) The above expression for - satisfies the conditions expressed by equation (194) for the following values of the constants found by trial : 7^ = 01, ^=.93, 7i2=.17, (1 — A:J=.07. Therefore from equation (193) the vertical velocity at any depth ?/ equals W = —2960 $1^1 = —296,0 (.0093e-01* — .0119e-17*) (197) az and from equation (192) the ratio of the upward flux within a dis- tance z from the coast to the total flux is proportional to /(z) = l_.93e-01* — .07e-1T* (198) where z is the distance from the coast in miles. The values of /(«) and -^5 — are tabulated with respect to z in table 14. dz OCEAN TEMPERATURES 405 TABLE 14 Tabulation of the functions f(z) and dz z /(*) dm z /(*) df(z) dz dz 0 0 .0212 40 .380 .0062 1 .020 .0192 50 .430 .0057 2 .040 .0175 70 .530 .0046 3 .060 .0161 100 .660 .0035 4 .075 .0150 200 .870 .0013 5 .090 .0139 300 .950 .00046 10 .150 .0105 400 .980 .00020 15 .190 .0089 500 .994 .00006 20 .240 .0080 700 .9992 .00000 30 .310 .0070 1000 .99995 .00000 Thus it appears that 90 per cent of the upward flux is confined to a coastal belt about 250 miles wide. Finally the stream line equation (188) becomes 17*l = C2 (199) _ ,93e-01* — . _ e-?rcos H 1 for the San Diego region, and the stream lines corresponding to C2 equal 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1.0 are shown in figure 17. •15 0 liOO Fig. 17. Traces of theoretical surfaces of flow on a vertical plane perpen- dicular to the coast. The flow included between any two consecutive surfaces is one-tenth of the total amount. 406 MISCELLANEOUS STUDIES Figure 17 represents the component of the hypothetical circulation in a plane perpendicular to the coast corresponding to a uniform \\ind over the whole region, in which the bottom bends sharply upward at the coast, but gives some idea of the actual circulation. In examining the figure it must be noted that the vertical is very much greater than the horizontal scale. In fact, if the horizontal scale were the same as the vertical one actually used the diagram would be about one and one-half miles in length. DEDUCTION OF THE UPWELLING VELOCITY OFF SAN DIEGO FROM THE OBSERVED RELATION OF SALINITY TO DEPTH If the rates of molecular diffusion of salts and conduction of heat are relatively very small as compared with the rate of transfer due to the alternating circulation (p. 368), the differential equation W (200) 6t dy2 dy (equation 80, p. 368) applies in general where the constant p- is a measure of the rate of transfer, and the dependent variable is the salt concentration or temperature. An application to temperature data has already been made, and we have only to replace 0 by the salinity 8 in the temperature equation and its solution already worked out (pp. 375-378) in order to obtain the corresponding formulae for salinity. However, the salinity data are too incomplete to furnish reliable estimates of averages for each month, and it seemed best to use the data taken in the same region (Section 404) for each of the three months, August, 1912. February, 1913, and April, 1913, which correspond to an interval of less than one year. These data are presented in table 15. OCEAN TEMPEEATUEES 407 TABLE 15 Observed Salinities for August, 1912, February, 1913, and April, 1913, in Section 40t Depth Salinities y (i = 2) February 0-4) April 0-8) August Mean annual values 0 33.47 33.58 33.75 33.61 10 33.47 33.58 33.69 33.58 20 33.44 33.58 33.58 33.51 30 33.42 33.61 33.54 33.48 40 33.46 33.66 33.57 33.52 50 33.50 33.73 33.65 33.57 60 33.54 33.79 33.73 33.63 70 33.57 33.85 33.57 33.67 80 33.62 33.90 33.81 33.72 90 33.66 33.94 33.85 33.76 100 33.70 33.99 33.88 33.79 150 34.03 34.19 34.07 34.05 200 34.25 34.30 34.17 34.21 300 34.32 34.33 34.23 34.27 400 34.33 34.34 34.28 34.30 500 34.36 34.35 34.32 34.34 600 34.40 800 34.48 1100 34.53 From the formula for salinity (replacing & by 8 in equation 117) it follows that the mean of any two salinities corresponding to a time interval of six months would equal approximately the mean annual salinity. Accordingly, the means of the salinities for February and August are assumed to be the mean annual salinities in this case. The constants C, D, and A of equation (117) were found as in the case of temperature data by fitting the equation Sm=Ce** + D (201) to the observed mean annual salinities, Sm. Then the observed mean annual salinity was subtracted from each of the entries under February and April, and the expression was subtracted from each of these, using the same numerical values for wt, r and a as on page 377, and the value of C determined above. The remaining expression Me™ cos (at -f &!# — e') 408 MISCELLANEOUS STUDIES (p. 377) was fitted to these remainders. The values of the constants thus found are D = 34.55, C = — 1.25, A= —.005, M=— .6, f' = — 65, a1==— .0075, /i2= 10,600, wj==— 53, 61==— .00495. The value of &! determined from equation (121) exceeds numerically the value — .00175 determined from the observations. Expressing the angle in degrees, these values are — .28 and — .10 respectively. The values n2 = 10,600 and wl = — 53 obtained from the salinity data are in good agreement with the values 7760 and — 31 obtained from the more complete and extensive temperature data (p. 378). The com- puted and observed values of the remainders and of the mean annual salinities are entered in table 16 as an additional test of the theory. The computed remainders were obtained from _ .6 e-. DOTS, cos (30£ _ ly _j_ 65) ° and the computed mean annual salinities were obtained from 34.55 — 1.25 e-005". TABLE 16 Computed and Observed Remainders for February and April, and the Computed and Observed Mean Annual Salinites Remainders Mean annual Depth Salinities < = 2 Feb. t = 4 April y Computed Observed Computed Observed Computed Observed 50 .14 -.07 .32 .16 33.53 33.57 100 .07 -.09 .21 .20 33.74 33.79 150 .02 -.02 .13 .14 33.96 34.05 200 .00 .04 .08 .09 34.04 34.21 300 -.01 .05 .03 .06 34.22 34.27 400 -.01 .03 .01 .04 34.33 34.30 500 -.01 .02 .00 .01 34.40 34.34 600 34.44 34.40 800 34.48 34.48 1100 34.50 34 . 53 The mean velocity of upwelling can also be estimated from the salinity distribution in the upper 30 meter layer, and by an entirely different method. A comparison of this value with the two estimates made with the aid of theoretical results already presented affords a severe test of the theories and gives an idea of the reliability of the OCEAN TEMPEEATUBES 409 Water Sc/rface results. In dealing with mean annual values we can assume all con- ditions to be independent of the time, from which it follows that the total amount of water in a given volume remains constant and the total amount of salts remain constant. Therefore the rate of flow of water and salts into the volume must equal the rate of flow out of the volume. This principle will be applied to two different volumes, thus giving two estimates of the velocity of the up- welling. First, consider a vertical column (fig. 18) whose cross section is a square of unit area and whose base is at the depth y2 where the salinity has its minimum value (Mc- Ewen, 1916, p. 272). The explanation of symbols used follows : Coast Bottom S = the salinity at any depth y. $0 = the salinity at the surface. S2 = the salinity at the depth y2. r2Wl = the vertical velocity at the depth y2, Wi is the maximum value, and corresponds to large values of y (table 13). y = the horizontal velocity. E = ihe rate of evaporation at the surface. Fig. 18. Eectangular volume of water from the depth y2 of mini- mum salinity to the surface, used in determining the velocity of up- welling from salinity. A flow into the volume is regarded as negative, and a flow out is regarded as positive, the vertical distances and velocities are regarded as positive when directed downward from the surface, and horizontal distances and velocities are positive when directed away from the coast. Because of the invariability of the amount of water in the volume r2W1 — E+fvdA = (202) 410 MISCELLANEOUS STUDIES where dA is an element of the vertical surface enclosing the column, and the integral is taken over the whole vertical surface. Similarly because of the invariability of the amount of salts in the volume r2W18a +fvSdA = 0. (203) Let S = S + *S (204) where S is the constant mean salinity for the whole volume and AS is a variable increment. Then equation (203) becomes (205) and substituting the value of J Vd A from equation (202) we have raW18a — '8(r.tWl — E) +JV(Afl)OOOOW^»flW fe~ ^^ l^ ^J^ CO CO CO CO CO ^* *O 7111111111 /*yi osot-ooTjiosooe^oo Jo ' (* "I" O 00 CO OO CO CO CO Is- ^t* *O 5lCN(N(M-„(,-,)* 00^(-coic<*'3|oo ^-(i-H^HOOOOOOO 1 1 1 1 1 1 1 1 1 1 loo >OiOOOiOO500O^Q>-( ^CNOO500t>-t>-COCOiO COCOCOiOU3U3»OiC>OiO co oo co co co co oo co co oo 00 OO 00 00 OO OO OO CO 00 00 s OO«OOCNiOOO'-i'«tit--O i-H r-t i-H C1 CN CN OO OCEAN TEMPERATURES 415 Except for the first two values of y^ near the surface, where the water is most disturbed, and for the largest value of t/15 where the difference (S2 — SJ is so small that it is subject to the largest pro- portional error, the computed values of the velocity Wx shown in the last column are in good agreement. And the mean of the central values, which are subject to the least error, is about — 35, which is the best estimate from the available data and agrees well with the values — 31 and — 53 found before, page 408. CONCLUSION In the case of no average flow of the water the form of a function giving the rate of gain of heat and of another giving the rate of loss of heat from a small volume of water at a given latitude and depth, was developed from a few simple assumptions, suggested by laboratory experiments as well as field observations. Equating the sum of these two expressions to the product of the specific heat by the volume by the rate of change of temperature resulted in a differential equation whose solution gave the temperature from the surface to a depth of ten meters as a known function of time, depth, latitude, and certain physical constants, under the conditions of no average flow of water. From observations on the relation to latitude of the mean annual surface temperature and the annual temperature range and the relation to latitude of the mean annual solar radiation and its annual range, all of the physical constants of the formula were computed. The lag between the time of the temperature maxima and minima and the time of the maximum and minimum values of the solar radia- tion deduced from these constants agreed well with the observed value. Also the mean monthly temperature at a region whose mean annual temperatures agree well with the normal value for the latitude, that is, the value corresponding to no average flow, would be expected to agree with those computed from the formula for normal temperature. A comparison of such computed and observed temperatures for a series of latitudes from 20° N to 40° N indicated a very satisfactory agreement. If the rate of change of temperature due to some factor not in- cluded in the above reasoning is known this quantity can be added to the differential equation already derived. Since all of the constants of the original differential equation are known the solution of the modified equation will give the temperature due to the new factor. 416 MISCELLANEOUS STUDIES If, for example, there is a flow of the water, the rate of flow multiplied by the temperature where the water enters a given element of volume gives the rate at which the heat is carried into the volume. The rate at which the heat leaves the volume, computed in the same way, subtracted from the rate at which it enters gives the rate of change of heat in the volume due to the corresponding ocean current, whether horizontal or vertical. A term expressing this rate of change of heat in the case of a horizontal current was added to the differential equation, and the solution furnished a means of estimating the magni- tude of horizontal currents from surface temperatures without con- sidering the causes of the currents. Numerical applications of this formula to a region of the North Pacific off the California coast and of the North Atlantic off the African coast gave estimates of the horizontal flow in good agreement with direct observations and with what would be expected from the observed wind velocity. Conclusive evidence of the presence of currents directed upward from the bottom along the California ccast which cause reduction in temperature has been published before; but to test this conclusion further it was assumed that the reduction of the temperature of the coastal water was due entirely to the upwelling of deep water, and the temperature distribution at depths exceeding 40 meters was assumed to result from a flow of heat according to Fourier's well known conductivity equation, in which a term expressing the rate of loss of heat due to upwelling was added. The formal solution of this equation contained certain physical constants whose evaluation re- quired the observed monthly temperatures at a series of depths. Our temperature data for a deep water region twenty miles offshore from San Diego were sufficient for making approximate estimates of all of the constants, of which the velocity of upwelling and the term corre- sponding to conductivity are of special interest. The latter constant depends largely upon the eddy motion, or alternating circulation, which tends to mix the water and has been called eddy conductivity or Mischungsintensitat, and was found in this case to be several thousand times the laboratory value. In dealing with salinities the same formula can be used; and a similar constant appears, which also depends largely on the mixing motion of the water, and would be expected to have practically the same value as that determined from temperatures. Our salinitiy data, though not so complete as the temperature data, confirmed this conclusion and gave approximately 417 the same velocity of upwelling. Moreover, in applying hydrodynamical equations to problems of oceanic circulation the coefficient of viscosity must be replaced by another constant depending on the eddy, or turbulent motion, and having a much greater value than the laboratory value obtained from observations on a slow laminar flow free from irregular motions. Similar results have also been found by G. I. Taylor in certain recent studies of the temperature, water vapor, and velocity in the atmosphere. The results of laboratory experiments and theories based on them were helpful but could not provide the numerical values required; in each case field observations were neces- sary. Furthermore, since the eddy conductivity, or Mischungs- intensitat, is not a physical constant of the substance, sea water or air, but depends upon the intensity and character of the circulation, its value will vary accordingly. The following approximate values of these constants, the coefficient of viscosity, diffusion, and conductivity under laboratory conditions and estimated from field observations in the ocean and the atmosphere, illustrate the great differences between field and laboratory conditions. TABLE 19 Estimates of the coefficients of viscosity, diffusion, and heat conductivity made from field observations in the ocean and atmosphere compared ivith values obtained in laboratory experiments Sea Water Observer Coefficient Laboratory value in c. g. a. units Value from field observations in c. g. s. units Ratio of the field to the laboratory value Ekman Jacobsen Viscosity1 Diffusion .014 .0000125 217 .3 to 11.4 15,500 24,000 to McEwen Diffusion .0000125 40 320,000 McEwen Conductivity2 .0012 30 25,000 Air Taylor Taylor Viscosity1 Conductivity2 .13 .20 770 to 6,900 570 to 3,400 6,000 to 50,000 3,000 to 17,000 1 The laboratory value of the "kinetic coefficient" of viscosity, or the coefficient of viscosity divided by the density, is given since it is the constant in the equations of motion, which is formally equivalent to the one given by field observations. 2 The laboratory value of the thermometric conductivity is given since that is the constant in the equation of heat conductivity, which is formally equivalent to the one given by field observations. The estimation of the effect of upwelling on the surface tempera- ture made necessary the consideration of results obtained for depths 418 MISCELLANEOUS STUDIES below the 40 meter level and the solution of the original differential equation for surface temperatures after adding a term giving the rate of temperature change due to upwelling. The monthly values deduced in this way for the San Diego region agree very well with those afforded by the observations. From the magnitude of the vertical velocity found from tempera- tures and from certain results deduced from Ekman 's hydrodynamical theory, the distribution of the horizontal and vertical velocity of the water in a vertical plane perpendicular to the coast was deduced and represented graphically. An independent estimate of the velocity of upwelling made from the distribution of salinities in the upper 30 meter layer and of the rate of evaporation at the surface agreed well with the other two estimates. 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On the annual range of temperature in the surface waters of the ocean and its relation to other oceanographic phenomena. Geog. Jour., 12, 113-137. MURRAY, Sir JOHN, AND HJORT, JOHAN. 1912. The depths of the ocean. (London, Macmillan), xx + 821 pp., 9 pis., 575 figs, in text. NANSEN, F. 1913. The waters of the north-eastern North Atlantic. Intern. Rev. d. ges. Hydrobiol. u. Hydrog., 4, 1-139, pi. 17, figs. 1-52 in text. PETERSEN, JOHANNES 1912. Hydrographie und Meteorologie Finnlands und der benachbarten Meere, nach "Atlas de Finlande." Ann. Hydr. u. marit. Meteor., 40, 131-145, 4 figs, in text. PULS, CASAR. 1895. Oberflachentemperaturen und Stromungsverhaltnisse des Aequatorial- giirtels des Stillen Ozeans. Aus dem Archiv der deutschen See- warte, 18, 1-38, pis. 1-4. SCHMIDT, WILHELM. 1915. Strahlung und Verdunstung an freien Wasser flachen. Ein Beitrag zum Warmehaushalt des Weltmeers und um WTasserhaushalt der Erde. Ann. Hydr. u. marit. Meteor., 43, 111-124. OCEAN TEMPERATURES 421 SCHOTT, G. 1895. Die jahrliche Temperaturschwankung des Oceanwassers. Petermanns Mittelungen, 41, 153-159, pi. 10. 1902. Oceanographie und maritime Meteorologie. Wissenschaftliche Ergeb- nisse der deutschen Tief see-Expedition auf dem Dampfer "Val- divia," 1898-1899. (Jena, Fischer), 1, xii + 403 pp., 26 pis. and 35 figs in text. SCHOTT, GERHARD, UND SCHU, FRITZ. 1910. Die Warmeverteilung in den Stillen Ozeans. Ann. Hydr. u. marit. Meteor., 38, 1-26, 15 pis. 1 fig. in text. SCHOTT, G., SCHULZ, B.r UND PERLEWITZ, P. 1914. Die Forschungsreise S.M.S. " Mb'we, " im Jahre 1911. Aus dem Archiv der deutschen Seewarte, 37, vi + 104 pp., 8 pis. and 16 figs, in text. TAYLOR, G. I. 1915. Eddy motion in 'the atmosphere. Philos. Trans. Eoyal Soc. London,. 215, ser. A, pp. 1-26, figs. 1-5 in text. THORADE, H. 19'09. Ueber die Kalifornische Meeresstromungen, Oberflachentemperaturen und Stromungen an der Westkiiste Nordamerikas. Ann. Hydr. u. 9 marit. Meteor., 37, 17-34, 63-77, pis. 5, 10, 11, 5 figs, in text. • 1914. Die Geschwindigkeit von Triftsstromungen und die Ekmansche Theorie. Ibid., 42, 379-391, 3 figs, in text. WEGEMANN, G. 1905rt. Die vertikale Temperaturverteilung im Weltmeere durch Warmeleit- ung. Wissenschaftliche Meeresuntersuchungen, herausgegeben von der Kommission zur Untersuchung der deutschen Meere in Kiel und der Biologischen Anstalt auf Helgoland. Abteilung Kiel, N. F., 8, 137-143. .1905&. Ursachen der vertikalen Temperaturverteilung im Weltmeere unter besonderer Beriicksichtigung der Warmeleitung. Ann. Hydr. u. marit. Meteor., 33, 206-211. WHARTON, W. J. L. 1894. Presidential address, Section E, Geography. Eept. Brit. Assoc. Adv. Sci. WlNKELMANN, A. 1906. Handbuch der Physik. (Leipzig, Earth), 3, xiv + 1178, 206 figs, in text. ZOPPRITZ, K. 1878. Hydrodynamische Probleme in Beziehung zur Theorie der Meeres- stromungen. Wiedemanns Annalen, 3, 582-607. CHANGES IN THE . CHEMICAL COMPOSITION OF GRAPES DURING RIPENING BY F. T. BIOLETTI, W. V. CRUESS, AND H. DAVI [University of California Publications in Agricultural Sciences, Vol. 3, No. 6, pp. 103-130] CHANGES IN THE CHEMICAL COMPOSITION OF GRAPES DURING RIPENING BY F. T. BIOLETTI, W. V. CRUESS, AND H. DAVI The investigations reported in this paper were undertaken to determine the changes in chemical composition of vinifera varieties of grapes in California during the growing and ripening stages. A survey of the literature indicated that, although the subject had been quite fully investigated in Europe with vinifera varieties and in America with the native varieties, very little had been published upon the ripening of vinifera varieties under California Conditions. A great many analyses of different varieties of grapes have been made by chemists of the University of California Experiment Station, nota- bly by G. E. Colby, and are reported in the publications of this station.1 A paper by G. E. Colby2 gives data upon the nitrogen content of a number of varieties of ripe vinifera grapes. Most of the analyses, however, do not show the changes in composition during ripening. Of the more recent European investigations3 some deal with the changes in general composition, others are confined to a discussion of a single component, such as sugar, or coloring matter, or acid principles. The changes in composition of American varieties of grapes during ripening have been studied quite thoroughly by W. B. Alwood4 and his associates. These investigations gave particular attention to the 1 Hilgard, E. W., The composition and classification of grapes, musts, and wines. Eept. of Viticultural Work, Univ. Calif. Exper. Sta. Rep., 1887-93, pp. 3-360. 2 Colby, G. E., On the quantities of nitrogenous matters contained in Cali- fornia musts and wines. Ibid., pp. 422-446. s Kelhofer, W., The grape in the various stages of maturity; trans, by E. Zardetti. Gior. Vin. Ital., vol. 34 (1908), no. 30, pp. 475-477. Barberon, G., and Changeant, F., Investigations on the development and [103] 424 MISCELLANEOUS STUDIES increase in sugar content and changes in acidity during the period in which the grapes were under observation. Alwood and other mem- bers of the Bureau of Chemistry, United States Department of Agri- culture, have also published a number of reports4 on the general composition of American varieties of grapes as affected by season, locality, etc. The most notable changes taking place during ripening were found by the European and American investigators mentioned above to be : (1) increase in total sugar ; (2) decrease in ratio of glucose to fructose ; (3) decrease in total acid; (4) increase in ratio of cream of tartar to total acid due to decrease in total acid ; (5) decrease in tannin ; and (6) increase in coloring matter. The cream of tartar and protein change very little in percentage during ripening, although, according to the composition of varieties of grapes in Abraon-Durso. Ann. Soc. Agr Sci. et Ind., Lyon (8), vol. 1 (1903), pp. 97-159. Laborde, J., The transformation of the coloring matter of grapes during ripening. C. R. Acad. Sci. (1908), vol. 17, pp. 753-755. Martinand, V., On the occurrence of sucrose and saccharose in different parts of the grape. C. R. Acad. Sci. (1907), vol. 24, pp. 1376-79. Eoos, L., and Hughes, E., The sugar of the grape during ripening. Ann. Falsif. (1910), vol. Ill, p. 395. Bouffard, A., Observations in regard to the proportion of sugar during ripen- ing. Ann. Falsif. (1910), vol. Ill, pp. 394-5. Zeissig, Investigations on the process of ripening on one-year-old grape wood. Ber. k. Lehranst. Wien, Obst-u. Garten-bau (1902), pp. 59-64. Koressi, F., Biological investigations of the ripening of the wood of the grape. Rev. Gen. Bot., vol. 13 (1901), no. 149, pp. 193-211; no. 150, pp. 251-264; no. 151, pp. 307-325. Brunet, R., Analysis and composition of the grape during ripening. Rev. de Viticulture, vol. 37, pp. 15-20. Garina, C., Variations in the principal acids of grape juice during the process of maturing. Canina. Ann. R. acad. d'agricultura di Torino, vol. 57 (1914), p. 233. Cf. Ann. Chim. applicata, vol. 5 (1914), pp. 65-6. See also Ann. r. acad. d'agr. di Torino, vol. 57, pp. 233-90. Baragolia, W. L, and Godet, C., Analytical chemical investigations on the ripening of grapes and the formation of wine from them. Landw. Jahrb., vol. 47 (1914), pp. 249-302. Riviere, G., and Bailhache, G., Accumulation of sugar and decrease of acid in grapes. Chem. Abs. Jour. (1912), p. 1022; Jour. Soc. Nat. Hort. France (4), pp. 125-7; Bot. Cent., 1912, pp. 117, 431. Pantanelli, Enzyme in must of overripe grapes. Chem. Abs. Jour., vol. VI (1912), p. 2447. < Alwood, W. B., Hartmann, J. B., Eoff, J. R., and Sherwood, S. F., Develop- ment of sugar and acid in grapes during ripening. U. S. Dept. Agric. Bull. 335, April 11, 1916. The occurrence of sucrose in grapes. Jour. Indust., vol. II, Eng. Chem. (1910), pp. 481-82. Sugar and acid content of American native grapes. 8th Inter. Cong. Appl. Chem. (1912), Sect. Vla-XIv, pp. 33, 34. Enological Studies: the chemical composition of American grapes grown in Ohio, New York, and Virginia. U. S. Dept. Agric. Bur. Chem. Bull. 145, 1911. — Crystallization of cream of tartar in the fruit of grapes. U. S. Dept. Agric. Jour. Agric. Research (1914), pp. 513, 514. Alwood, W. B., Hartmann, B. G., Eoff, J. R., Sherwood, S. F., Carrero, J. O., and Harding, T. J., The chemical composition of American grapes grown in the central and eastern states. U . S. Dept. Agric. ( 1916) Bull. 452. CHEMICAL COMPOSITION OF GRAPES 425 investigations referred to, there is a slight increase in both of these constituents. In the investigations reported in the present paper, particular attention was given to increase in total solids and sugar, decrease in total acid, and changes in protein and cream of tartar in the must or juice of the grapes. The ripening of the leaves was traced by noting the changes in starch, sugar, acid, and protein content. Sampling. — During 1914 and 1915 samples of fruit were taken from the time the grapes had reached full size but were still hard and green until they had become overripe. During 1916 the first samples were taken shortly after the berries had set and before the seeds had formed. The last samples were taken when the grapes had become overripe. Samples of leaves were also taken in 1916 on the same dates that samplings of the grapes were made. The samples were taken at intervals of approximately one week. They were in all cases taken from the experimental vineyard at Davis.5 Five-pound samples of grapes were used. The grapes were picked from the first crop, except in 1914, when a comparison of the ripening of first and second crops was made. An ordinary five-pound grape basket was filled with leaves at each sampling. The samples of grapes and leaves were shipped from the vineyard to the laboratory at Berkeley, where the grapes were placed in an Enterprise fruit crusher and pressed. The juice was sterilized in bottles at 212° F. The leaves were ground in an Enterprise food chopper and sterilized at 212° F in wide mouth, air tight bottles. The samples were then reserved for chemical examination. In 1914 it was found that there was considerable irregularity in the variation of samples from week to week. For example, instead of an increase of total solids during the periods between samplings, a slight decrease was found in a few samples. During the 1915 season it was therefore considered of interest to note what effect certain factors might have upon the composition of samples taken on the same date. 1. Effect of Age of Vine. The entire first crop from three large old vines and from three small young vines, all of the Muscat variety, was picked, crushed, and pressed. Analyses of the juices were made with the following results : 5 The authors wish to express their appreciation of the assistance of F. C. Flossfeder, of the University Farm at Davis, who gathered most of the samples reported upon in this paper. 1105} 426 MISCELLANEOUS STUDIES TABLE 1 — EFFECT OF AGE OF VINE ON BALLING AND ACID OF MUST OF MUSCAT GRAPES Vine Balling Acid Small, no. 1 24.7 .67 Small, no. 2 27.7 .49 Small, no. 3 27.6 .67 Large, no. 1 22.0 .88 Large, no. 2 23.5 .75 Large, no. 3 23.6 .76 Average, small 26.7 .61 Average, large 23.0 .81 Difference 3.7 — .20 The results show rather strikingly that young vines ripen their fruit earlier than do mature vines. This fact makes it essential that samples, to be comparative, must be taken from vines of the same age. 2. Comparison of Grapes from North and South Sides of Vines. The whole first crop from three large Muscat vines was picked. The bunches from the north and south sides of each vine were kept sep- arate. They were crushed, pressed, and analyzed for Balling and acid content. TABLE 2 — COMPARISON OF BALLING AND Aero OF JUICE FROM GRAPES PICKED FROM NORTH AND SOUTH SIDES OF VINES Vine and side of vine Balling Acid 1-N 21.3 .92 1-S 22.7 .84 2-N 23.5 .81 2-S 23.5 .80 3-N 23.1 .81 3-S 24.1 .71 Average, N side 22.63 .85 Average, S side 23.43 .78 Difference 80 —.07 The tests indicate that grapes located on the south side of the vine ripen more rapidly than those on the north side. This difference is apparently due to the fact that the south side of the vine receives more heat than the north side. 3. Effect of Location of Bunch on Cane. Grapes of first crop, from canes showing two bunches each, were picked and the bunches from near the bases of the canes kept separate from those near the tip of the cane. They were crushed, pressed, and analyzed for Balling and acid. [106] X CHEMICAL COMPOSITION OF GRAPES 427 TABLE 3 — EFFECT OF LOCATION OF BUNCH ON CANE Nearest base of cane Nearest tip of cane Vine Balling Acid Balling Acid Muscat, no. 1, cane 1 25.1 .73 23.7 .83 Muscat, no. 1, cane 2 25.6 .79 24.8 .80 Muscat, no. 2, cane 1 25.1 .85 24.6 .87 Muscat, no. 2, cane 2 25.2 .78 24.7 • .85 Muscat, no. 3, cane 1 23.0 .79 22.6 .82 Muscat, no. 3, cane 2 24.5 .73 23.8 .73 Muscat, no. 4, cane 1 24.2 .90 25.2 .90 Muscat, no. 4, cane 2 24.5 .68 23.8 .83 Tokay, cane 1 21.2 .67 21.2 .80 Tokay, cane 2 23.0 .63 22.4 .76 Sultanina, cane 1 23.3 .61 22.3 .62 Sultanina, cane 2 22.5 .61 23.0 .63 Sultana, cane 1 23.2 .78 21.6 .70 Sultana, cane 2 21.1 .90 20.0 1.20 Palomino, cane 1 25.1 23.5 Palomino, cane 2 22.0 23.7 Means 24.9 .75 23.1 .81 The data indicate that bunches at the base of the cane ripen in most cases more rapidly than those near the tip, although this relation does not always hold and may be reversed in some instances. 4. Variation in Balling Degree of Must from Bunches of Similar Appearance and Size from Same Vineyard and Gathered on Same Date. A five-pound basket of grapes of first crop and selected for similarity of color, size of bunch, and general appearance was picked from each of a number of vines in the same vineyard. Vines of similar size and appearance were chosen. Several varieties were rep- resented in the experiment. Tests of Balling degree only were made. TABLE 4 — VARIATION IN BALLING IN MUST FROM GRAPES OF SAME VARIETY PICKED FROM DIFFERENT VINES OF SIMILAR APPEARANCE Vine Mean Maximum Variety number Balling Balling variation Cornichon 3 14.5 ...... Cornichon 6 15.0 Cornichon 9 14.2 Cornichon 11 14.7 Cornichon 16.1 14.9 1.9 Emperor 10 12.0 Emperor 11 14.5 Emperor 13 15.2 Emperor 14 15.5 Emperor 17 15.0 14.4 3.5 Malaga 5 . 18.5 Malaga 6 17.2 [107] MISCELLANEOUS STUDIES TABLE 4 — (Continued) Vine Mean Maximum Variety number Balling Balling variation Malaga 7 19.7 Malaga 9 18.5 Malaga 11 19.2 18.6 2.0 Muscat * 21.7 Muscat * 21.1 Muscat * 20.9 ....:. Muscat * 21.5 Muscat * 21.7 21.4 .8 Palomino 3 19.5 Palomino 4 21.0 Palomino 6 21.2 Palomino 7 20.7 Palomino 9 18.8 20.2 2.4 Sultanina * 22.5 Sultanina * 21.5 Sultanina * 18.7 Sultanina * 22.0 Sultanina * 22.6 21.5 3.9 Tokay * 19.8 Tokay * 19.3 Tokay * 18.7 Tokay * 20.7 Tokay * 19.5 19.6 2.0 Pedro Zumbon 7 21.5 Pedro Zumbon 4 21.2 Pedro Zumbon 6 20.6 Pedro Zumbon 3 18.5 Pedro Zumbon 5 19.8 20.3 3.0 Emperor 15 18.1 Emperor 8 15.8 Emperor 14 16.2 Emperor 9 16.8 Emperor 16 16.3 16.6 2.3 Cornichon 4 17.3 Cornichon 9 16.3 Cornichon 10 17.9 Cornichon 11 17.8 Cornichon 13 18.0 17.5 1.7 Malaga 4 18.3 Malaga 5 20.4 Malaga 6 20.0 Malaga 8 20.1 19.7 1.8 Mean variation, six ripest varieties 2.32 Mean variation, six least ripe varieties 2.20 Average variation, whole series 2.30 Adjacent vines. CHEMICAL COMPOSITION OF GRAPES 429 The data illustrate the difficulty of selecting five-pound lots of the same variety that will represent average samples. 5. Effect of Location of Berries on the Bunch. All of the bunches of the first crop were taken from two Muscat vines. • The bunches were cut into top and bottom halves. These lots were crushed sep- arately, pressed, and the juices analyzed. TABLE 5 — EFFECT OF LOCATION OF BERRIES ON BUNCH Sample Balling Acid Vine no. 1, stem end of bunch 23.6 .76 Vine no. 1, apical end of bunch 22.7 .87 Vine no. 2, stem end of bunch 21.3 .92 Vine no. 2, apical end of bunch 21.3 .93 The results show that considerable variation in composition of the berries may exist within the same bunch. 6. Effect of Thoroughness of Pressing. About ten pounds of Mus- cat grapes were crushed and lightly pressed. The pulp and skins left from this pressing were then thoroughly crushed and pressed a second time. The juices from the two lots were analyzed separately. TABLE 6 — EFFECT OF THOROUGHNESS OF PRESSING Sample Balling Acid First pressing 22.8 .78 Second pressing 22.8 .79 There was practically no difference between the juices from lightly and thoroughly pressed grapes of the same lot. The data from the above six tests indicate that it is a very difficult matter to select grapes that will represent a fair average sample of the grapes to be studied. The size and age of the vine, the side of the vines, the location of the bunch on the cane, and individual vines, all affect the composition of the juice from the grapes very materially, and these factors should be taken into account when samples are taken. Preservation of Samples and Preparation for Analysis. — In 1914 the samples of juice were preserved with HgCl2, 1 :1000. In 1915 and 1916 the samples were sterilized at 100° C. Before analysis the bottles were heated to 100° C for an hour to dissolve any cream of tartar which might have separated. The juices were filtered before analysis. Con- siderable coagulation of dissolved solids took place during sterilization. [1091 430 MISCELLANEOUS STUDIES Methods of Analysis. — The samples were analyzed by the methods in use in the Agricultural Chemistry Laboratory and the Nutrition Laboratory of this station. A brief description of the methods follows : 1. Total Solids. The juice was filtered clear and cooled below 15° C. The specific gravity was determined by a pycnometer at 15? 5 C. The corresponding total solids, or extract, was found from Windisch's tables in Leach's Food Analysis, page 697. This table gives the extract as "grams per 100 grams"; that is, per cent by weight. To calculate the corresponding grams per 100 c.c., the per cent by weight was multiplied by the specific gravity. This gives a figure not very much greater than grams per 100 grams in juices of low specific gravity, but gives a figure as much as 2 per cent greater where the total solids are much above 20 per cent. The two methods of reporting total solids has in the past led to much unnecessary confusion. It is therefore urged that the reader bear in mind the distinction between the two methods when reading the discussions in this paper or examining the curves. 2. Sugar. The sample was filtered; an aliquot was treated with lead acetate ; diluted to mark ; filtered ; lead removed with anhydrous Na2C03, and the sugar determined in an aliquot by the gravimetric method, using Soxhlet's modification of Fehling's solution. The Cu20 was weighed directly after drying at 100° C. The corresponding sugar as invert sugar was obtained from Munson and Walker's table in Leach's Food Analysis. The grams of invert sugar per 100 c.c. found in this way was divided by the specific gravity of the must to obtain the corresponding grams per 100 grams of juice. 3. Total acid was determined by titration of a 10 c.c. sample with N/10 NaOH, using phenolphthalein as an indicator, and is reported as tartaric acid, grams per 100 c.c. 4. Cream of tartar was estimated by a method suggested by Pro- fessor D. R. Hoagland of the Division of Agricultural Chemistry. Ten c.c. of the juice was incinerated at a low heat in a muffle furnace until well carbonized, but not to a white ash. (Excessive heating results in loss of K by volatilization.) The K2C03 formed by incin- eration was leached out with hot water and a known excess of N/10 HC1 added. This was titrated back with N/10 NaOH, using methyl orange as an indicator. The K2C03 is obtained by difference and calculated back to cream of tartar, assuming that all of the K2C03 is formed by the oxidation of cream of tartar, KH(C4H406). It is [110] CHEMICAL COMPOSITION OF GRAPES 431 reported as grams KH(C4H4O6) per 100 c.c., and also as tartaric acid. 5. Free Tartaric Acid was obtained by difference between total acid and cream of tartar calculated as tartaric acid. It is reported as grams per 100 c.c. 6. Protein in the juice was determined by the usual Kjeldahl- Gunning method upon a 10 c.c. sample. It is reported as grams per 100 c.c. 7. Moisture in the leaves was determined by drying the sample at 100° C. 8. Sugar in the leaves was estimated by leaching the dried sample with cold water and determining sugar by the gravimetric Fehling method in the nitrate. 9. Starch in the leaves was determined by hydrolysis of the dried ground sample with dilute HC1 at 100° C., followed by nitration and the usual gravimetric Fehling method for juice described above. 10. Protein in the leaves was determined by the Kjeldahl-Gunning method on .5 gram samples. 11. Acid in the leaves was estimated by leaching in hot water and titrating in the presence of the leaves, using litmus paper as indicator. Analyses of Musts from Grape-Ripening Samples, 1914, 1915, 1916. The data from the analyses have been assembled in the following tables. Owing to the size of the tables, abbreviations have been necessary for the headings of the columns. EXPLANATIONS OP HEADINGS OF TABLES 1. Sp. gr. = Specific gravity at 15?5 C. 2. T. S. G. = Total solids in grams per 100 grams. 3. T. S. C. = Total solids in grams per 100 c.c. 4. S.G, = Sugar in grams per 100 c.c. 5. S. T. = Sugar in grams per 100 grams. 6. Tl. A. = Total acid in grams per 100 c.c. 7. C. T. = Cream of tartar in grams per 100 c.c. 8. C. T. T. = Cream of tartar as tartaric acid, grams per 100 c.c. 9. T. A. = Total free acid as tartaric obtained by subtracting cream of tartar as tartaric from total acid as tartaric. 10. P. = Protein, grams per 100 c.c. 11. S. = Sum of sugar, cream of tartar, tartaric acid, and protein in grams per 100 c.c. 12. T. S. — S. = Total solids (T. S. C.) — S (preceding column). [nil 432 MISCELLANEOUS STUDIES TABLE 7 — GEAPE RIPENING TESTS, 1914 (Grapes from Davis) Malaga First crop: Variety l 2 3 4 5 6 7 8 9 10 11 12 and date 8p.gr. T. 8. O. T. 8. C. 8. G. S.I. Tl. A. C. T. C. T. T. T. A. P. 8. T. 8. 6. Aug. 19 1.0396 10.25 10.65 7.32 7.04 2.78 .35 .13 2.65 .21 10.53 .12 Aug 26 1.0413 10.69 11.13 7.84 7.53 2.65 .36 .14 2.51 .25 10.96 .17 Aug. 26 1.0595 15.42 16.33 13.37 12.62 .77 .48 .19 .58 .55 14.98 1.41 Aug. 26 1.0613 15.87 16.84 14.31 13.50 1.46 .31 .12 1.34 .33 16.29 .55 Aug. 26 1.0694 18.01 19.25 16.59 15.52 1.00 .36 .14 .86 .38 18.19 1.06 Aug. 31 1.0732 19.00 20.39 17.65 16.45 .87 .55 .22 .65 .45 19.30 1.09 Sept. 23 1.0736 19.10 20.50 17.83 16.60 .74 .38 .15 .59 .52 19.32 1.18 Oct. 5 1.0965 25.12 27.54 24.89 22.70 .72 .50 .20 .52 .57 26.48 1.06 Second crop Aug. 10 1.0213 5.51 5.62 2.07 2.03 3.22 .23 .09 3.13 .17 5.60 .02 Aug. 31 1.0495 12.82 13.45 9.58 9.13 2.51 .40 .16 2.35 .28 12.61 .84 Sept. 14 1.0532 13.78 14.51 11.89 11.30 2.07 .37 .15 1.92 .31 14.49 .02 Sept. 23 1.0670 17.43 18.60 15.29 14.33 1.54 .50 .20 1.35 .29 17.43 1.17 Sept. 23 1.0869 22.59 24.55 22.04 20.19 1.07 .45 .18 .89 .41 23.79 .76 Oct. 5 1.0930 24.20 26.45 23.90 21.87 .94 .48 .19 .75 .41 25.54 .91 Tokay ( First crop: Aug. 2 1.0454 11.75 12.28 8.73 8.35 2.63 .46 .18 2.45 .32 11.96 .32 Aug. 10 1.0624 16.08 17.08 14.28 13.44 1.56 .45 .18 1.38 .27 16.38 .70 Aug. 19 1.0682 17.69 18.90 15.94 14.92 1.32 .45 .18 1.14 .27 17.80 1.10 Aug. 3i 1.0849 22.09 23.97 21.87 20.16 .63 .59 .23 .40 .40 23.26 .71 Sept. 4 1.0865 22.49 24.44 22.21 20.44 .77 .43 .17 .60 .32 23.56 .88 Sept, 4 1.0912 23.72 25.88 23.44 21.48 .59 .64 .25 .44 .41 24.93 .95 Sept. 23 1.0937 24.38 26.66 24.15 22.08 .58 .49 .19 .30 .39 25.33 1.33 Oct. 14 1.0991 25.80 28.36 25.55 23.25 .45 .54 .21 .24 .45 26.78 1.58 Oct. 14 1.1000 26.04 28.64 25.78 23.44 .52 .58 .23 .29 .58 27.23 1.41 Second crop Aug. 19 1.0657 17.04 18.16 15.03 14.10 1.91 .50 .20 1.70 .32 16.55 .61 Sept. 14 1.0701 18.19 19.47 16.68 15.59 1.29 .52 .21 1.11 .33 18.64 .83 Sept. 23 1.0769 19.95 21.48 19.22 17.85 1.01 .48 .19 .82 .40 20.92 .56 Oct. 14 1.0911 23.70 25.86 23.43 21.47 .69 .60 .24 .45 .40 24.88 .98 TABLE 8 — GRAPE RIPENING TESTS, 1915 (Grapes from Davis) Cornichon Variety 1 2 3 4 5 6 7 8 9 10 11 12 and date Sp.gr. T. S. O. T. 8. C. 8.0. 8. I. Tl. A. C. T. C. T. T. T. A. p. 8. T. 8. S. Aug. 22 1.0324 8.38 8.65 3.99 3.86 3.05 .58 .23 2.82 .38 7.77 .88 Sept. 1 1.0514 13.31 13.99 10.70 10.18 1.62 .61 .25 1.37 .42 13.10 .89 Sept. 15 1.0688 17.85 19.08 15.94 14.91 .97 .70 .28 .69 .43 17.76 1.32 Sept. 22 1.0723 18.76 20.12 16.97 15.83 .94 .71 .28 .66 .46 18.80 1.32 Sept. 29 1.0737 19.13 20.54 18.31 17.05 .87 .75 .30 .61 .66 20.33 .21 Oct. 7 1.0781 20.28 21.86 19.41 18.02 .71 .73 .29 .42 .48 21.04 .82 Oct. 14 1.0843 21.91 23.76 20.40 18.81 .78 .68 .27 .62 .66 22.36 1.40 Oct. 22 1.0873 22.70 24.68 21.06 19.37 .75 .78 .31 .44 .46 22.74 1.94 [112] CHEMICAL COMPOSITION OF GEAPES 433 TABLE 8 — (Continued) Emperor Variety l 2 3 4 5 6 7 8 9 10 ll 12 and date Sp. gr. T. S. G. T. S. C. S. G. S.I. Tl. A. C. T. C.T.T. T. A. p. S. T. A. S. Aug. 19 1.0420 10.87 11.33 6.96 6.68 2.33 .38 .15 2.18 .38 9.90 1.43 Sept. 1 1.0479 12.40 12.99 9.82 9.37 1.89 .40 .16 1.73 .62 12.57 .42 Sept. 7 1.0560 14.51 15.32 11.48 10.87 1.70 .47 .19 1.57 .54 14.00 1.32 Sept. 15 1.0632 16.37 17.40 14.88 14.00 1.40 .53 .21 1.18 .54 17.13 .27 Sept 22 1.0652 16.91 18.01 15.46 14.51 .93 .48 .19 .74 .55 17.23 .78 Sept. 29 1.0672 17.43 18.60 16.37 15.34 .91 .48 .19 .72 .66 18.23 .37 Oct. 7 1.0744 19.31 20.75 17.82 16.59 .79 .58 .23 .56 .51 19.47 1.28 Oct. 14 1.0765 19.86 21.38 18.37 17.06 .79 .59 .24 .56 .63 20.15 1.23 Oct. 22 1.0792 20.57 22.20 19.81 18.36 .75 .63 .25 .49 .66 21.59 .61 Malaga Aug. 19 1.0546 14.14 14.91 12.47 11.82 2.05 .36 .15 1.90 .75 15.48 .57 Aug. 2n 1.0651 16.86 17.96 14.53 13.64 1.66 .46 .18 1.48 .90 17.37 .59 Sept. 1 1.0678 17.59 18.78 16.75 15.69 1.38 .44 .18 1.20 .89 19.28 .50 Sept. 7 1.0719 18.66 19.50 17.00 15.86 1.29 .44 .18 1.11 .70 19.25 .25 Sept. 15 1.0758 19.68 21.17 18.17 16.89 1.21 .62 .25 .96 .70 20.45 .72 Sept. 22 1.0760 19.81 21.32 18.39 17.09 1.18 .61 .25 .93 .74 20.67 .65 Sept. 29 1.0812 21.20 22.92 18.48 17.09 1.07 .58 .23 .84 .75 20.65 2.27 Oct. 7 1.0838 21.78 23.61 21.03 19.40 1.07 .65 .26 .81 .73 23.22 .39 Oct. 14 1.0970 25.25 27.70 24.58 22.41 .59 .83 .33 .26 .88 26.55 1.15 Muscat Aug. 19 1.0615 15.94 16.92 13.93 13.12 1.70 .36 .15 1.55 .70 16.54 .38 Aug. 25 1.0744 19.31 20.75 17.96 16.72 1.21 .62 .25 .96 .62 20.16 .59 Sept. 1 1.0805 20.91 22.59 19.50 18.05 .79 .63 .25 .54 .63 21.30 1.29 Sept. 7 1.0827 21.47 23.25 20.39 18.83 .76 .65 .26 .50 .66 22.20 1.05 Sept. 15 1.0917 23.85 26.04 23.49 21.52 .96 .58 .23 .73 .58 25.38 .66 Sept. 22 1.0954 24.14 26.44 24.54 22.40 .77 .62 .25 .52 .85 26.53 .09 Sept. 29 1.1048 27.30 30.16 27.01 24.45 .72 .72 .29 .44 .72 28.89 1.27 Oct. 7 1.1079 28.12 31.15 28.28 25.53 .66 .59 .23 .43 .66 29.96 1.19 Pedro Zumbon Aug. 19 1.0555 14.38 15.18 11.96 11.33 1.81 .68 .27 1.54 .33 14.51 .67 Aug. 25 1.0588 15.24 16.14 13.77 13.01 1.09 .57 .23 .86 .53 15.73 .41 Sept. 1 1.0642 16.64 17.71 15.61 14.67 .58 .52 .21 .37 .43 16.93 .78 Sept. 7 1.0693 17.98 19.23 16.55 15.48 .84 .48 .19 .65 .73 18.41 .82 Sept. 15 1.0708 18.37 19.67 18.17 16.97 .56 .58 .23 .33 .64 19.72 . .05 Sept. 22 1.0912 23.72 25.88 23.02 21.10 .53 .87 .35 .19 .64 24.72 1.16 Sultana Aug. 19 1.0673 17.80 19.00 15.63 16.64 1.69 .33 .13 1.56 .32 17.84 1.16 Aug. 25 1.0746 19.37 20.82 17.96 16.71 1.44 .37 .14 1.30 .38 20.01 .81 Sept. 1 1.0815 21.17 22.90 20.26 18.73 1.14 .54 .22 .92 .50 22.22 .68 Sept. 7 1.0893 23.22 25.29 23.02 21.13 .78 .44 .18 .60 .34 24.40 .89 Sept. 22 1.0902 23.39 25.50 23.10 21.19 1.24 .50 .20 1.04 .38 25.02 .48 Sept. 29 1.0922 23.99 26.20 . 24.04 22.01 .80 .41 .17 .63 .42 25.50 .70 [113] 434 MISCELLANEOUS STUDIES TABLE 8 — (Continued) Sultanina Variety 1 2 3 4 5 6 7 8 9 10 11 12 and date Sp. gr. T. S.Q . T. S. 0. S. G. S.I. Tl. A. C. T. C.T.T. T. A. P. 8. T. A. b. Aug. 19 1.0673 17.46 18.64 15.87 14.87 1.27 .44 .18 1.09 .42 17.82 .82 Aug. 25 1.0743 19.26 20.69 18.30 17.03 1.19 .47 .19 1.00 .37 20.14 .55 Sept. 1 1.0771 20.02 21.56 18.98 17.62 .85 .49 .20 .65 .42 20.54 1.02 Sept. 7 1.0892 23.20 25.27 22.42 20.58 .72 .80 .32 .40 .62 24.24 1.03 Sept. 15 1.0927 24.12 26.36 23.62 21.62 .79 .76 .30 .39 .45 25.22 1.14 Sept. 22 1.0984 25.62 28.14 25.71 23.41 .60 .58 .23 .37 .45 27.11 1.03 Sept. 29 1.1049 27.33 30.20 27.41 24.81 .54 .51 .20 .34 .42 28.68 1.52 Toicay Aug. 19 1.0598 15.50 16.43 14.41 13.60 1.74 .41 .16 1.58 .29 16.69 .26 Aug. 25 1.0676 17.54 18.73 15.63 14.64 1.24 .39 .15 1.09 .69 17.80 .93 Sept. 1 1.0757 19.65 21.14 18.17 16.89 .84 .47 .19 .66 .44 19.74 1.40 Sept. 7 1.0781 20.28 21.86 19.11 17.73 .79 .45 .18 .61 .37 20.54 1.32 Sept. 15 1.0785 20.39 21.99 19.26 17.86 .74 .48 .19 .55 .40 20.69 1.30 Sept. 22 1.0798 20.73 22.38 20.17 18.68 .59 .51 .20 .39 .36 21.43 .95 Sept. 29 1.0823 21.38 23.14 20.76 19.18 .85 .58 .23 .62 .28 22.24 .90 Oct. 7 1.0830 21.57 23.36 20.87 19.27 .69 .63 .25 .44 .42 22.36 1.00 Oct. 14 1.0851 22.12 24.00 21.53 19.84 .65 .69 .28 .38 .36 22.96 1.04 Oct. 22 1.0895 23.28 25.36 22.91 21.03 .66 .72 .29 .37 .37 24.37 .99 TABLE 9 — GRAPE EIPENING TESTS, 1916 Burger Variety 1 2 3 4 5 6 7 8 9 10 11 12 and date Sp.gr. T. S. G. T. S. C. S. G. S. I. Tl. A. C. T. C. T. T. T. A. P. 8. T. S. S. June 12 1.0212 5.48 5.59 1.29 1.55 2.95 .55 .22 2.73 .44 5.27 .32 June 19 1.0195 5.04 5.88 .87 .88 2.88 .51 .21 2.67 .45 4.51 1.37 June 27 1.0220 5.69 5.82 1.25 1.28 2.94 .33 .13 2.81 .45 4.87 .95 July 7 1.0220 5.69 5.82 1.11 1.28 2.98 .49 .20 2.78 .31 4.86 .96 July 10 1.0200 5.17 5.27 .93 .95 3.32 .57 .23 3.09 .37 4.97 .30 July 19 1.0205 5.30 5.41 1.03 1.05 3.13 .55 .22 2.91 .35 4.86 .55 July 27 1.0225 5.82 5.95 1.13 1.15 2.93 .48 .19 2.74 .34 4.71 1.24 Aug. 3 1.0258 6.67 6.84 2.14 2.19 2.71 .63 .25 2.46 .40 5.68 1.16 Aug. 7 1.0330 8.53 8.83 3.36 3.46 2.67 .87 .35 2.32 .47 7.12 1.21 Aug. 16 1.0391 10.11 10.51 5.90. 6.13 .2.41 .95 .38 2.03 .46 9.57 .94 Aug. 23 1.0422 10.92 11.38 6.03 6.27 2.10 .98 .39 1.71 .63 9.59 1.89 Aug. 30 1.0529 13.70 14.42 9.95 10.42 1.15 1.03 .41 .74 .49 12.70 1.72 Sept. 5 1.0645 16.73 17.81 14.51 15.43 1.01 1.07 .43 .68 .61 17.79 .02 Sept. 12 1.0717 18.61 19.94 16.27 17.36 .95 .98 .39 .56 .82 19.72 .22 Sept. 20 1.0765 19.86 21.37 17.44 18.73 .87 1.06 .42 .45 .62 20.86 .51 Sept. 26 1.0808 20.99 22.68 18.48 19.99 .81 1.01 .40 .41 .83 22.24 .44 Cornichon June 12 1.0202 5.22 5.32 .91 .93 3.15 .64 .26 2.89 .32 4.78 .54 June 19 1.0200 5.17 5.27 .86 .88 2.96 .62 .25 2.71 .42 4.63 .64 June 27 1.0193 4.99 5.08 .84 .86 2.89 .39 .16 2.73 .56 4.54 .44 July 7 1.0201 5.19 5.29 .87 .89 2.88 .44 .18 2.70 .52 4.55 .74 July 10 1.0206 5.32 5.43 .85 .87 3.27 .54 .22 3.05 .53 4.99 .44 July 19 1.0225 5.82 5.95 1.28 1.30 3.11 .57 .23 2.88 .55 5.30 .65 July 27 1.0242 6.25 6.40 1.63 1.66 2.94 .54 .22 2.72 .44 5.26 .14 Aug. 3 1.0373 9.65 10.00 5.00 5.19 2.87 .59 .24 2.63 .56 8.97 1.03 [114] CHEMICAL COMPOSITION OF GSAPES 435 TABLE 9 — (Continued) . Variety l 2 3 4 5 6 7 8 9 10 11 12 and date Sp. gr. T. S. G. T. S. C. S. G. S.I. Tl. A. C. T. C T.T. T. A. P. S. T. A. S. Aug. 7 1.0375 9.70 10.06 5.28 5.48 2.79 .65 .26 2.53 .66 9.32 .64 Aug. 16 1.0434 11.23 11.71 6.30 6.57 2.75 1.06 .43 2.32 .53 10.48 1.23 Aug. 23 1.0635 16.47 17.51 12.19 12.96 1.85 1.06 .43 1.42 .58 16.02 1.49 Aug. 30 1.0685 17.77 18.97 14.75 15.61 1.16 1.10 .44 .72 .63 18.06 .91 Sept. 5 1.0694 18.01 19.25 15.03 16.07 .93 .90 .36 .57 .58 18.12 1.13 Sept. 12 1.0757 19.65 21.09 16.37 17.60 .87 1.14 .46 .41 .78 19.97 1.12 Sept. 20 1.0786 20.41 22.00 17.52 18.88 .84 .94 .37 .44 .59 20.85 1.15 Sept. 26 1.0828 21.52 23.30 18.52 20.03 .72 .83 .33 .39 .85 22.10 1.20 Muscat June 12 1.0203 5.25 5.35 .91 .93 2.93 . .65 .26 2.71 .38 4.67 .68 June 19 1.0199 5.14 5.24 .70 .72 3.37 .63 .25 3.12 .44 4.91 .33 June 27 1.0210 5.43 5.54 1.33 1.36 3.33 .48 .19 3.14 .49 5.47 .07 July 7 1.0210 5.43 5.54 1.63 1.66 3.32 .54 .22 3.10 .45 5.75 .21 July 10 1.0195 5.04 5.14 1.33 1.36 3.60 .55 .22 3.38 .36 5.65 .51 July 19 1.0251 6.49 6.65 2.55 2.61 3.40 .58 .23 3.17 .49 6.85 .20 July 27 1.0308 7.97 8.22 3.56 3.67 2.67 .66 .26 2.01 .45 6.79 1.43 Aug. 3 1.0488 12.64 13.26 9.72 10.19 1.77 .68 .27 1.50 .46 12.83 .43 Aug. 7 1.0582 15.68 16.58 12.72 13.53 1.60 .73 .29 1.31 .55 16.12 .46 Aug. 16 1.0803 20.86 22.53 16.81 18.15 1.16 .94 .38 .78 .51 20.38 1.70 Aug. 23 1.0910 23.67 25.82 20.20 22.04 .82 1.04 .42 .40 .56 24.04 1.78 Aug. 30 1.0972 25.30 27.75 21.87 22.99 .65 1.21 .49 .16 .58 25.94 1.81 Sept. 5 1.1023 26.64 29.36 23.28 24.74 .60 1.17 .47 .13 .65 26.69 2.67 Sept. 12 1.1101 28.70 31.85 25.95 27.83 .56 1.35 .54 .02 .69 29.89 1.96 Sept. 20 1.1122 29.25 32.72 26.43 29.39 .68 1.56 .63 .05 .58 31.27 1.45 Sept. 26 1.1133 29.54 32.89 26.68 29.70 .56 1.39 .56 .00 .59 31.57 1.32 TABLE 10 — CATAWBA GRAPE RIPENING TESTS (Table from U. S. Dept. Agric Catawba , Bulletin 335, by W. B. Alwood) 1912: . ' Variety l o 3 4 5 6 7 8 9 and date Sp. gr. T. S. G. T. S. C. S.I. S. G. Tl. A. C. T. C. T. T. Days Sept. 4 1.0329 8.51 8.84 3.60 3.72 3.68 .39 .16 0 Sept. 9 1.0419 10.84 11.29 6.68 6.96 3.02 .41 .16 5 Sept. 12 1.0515 13.34 14.03 9.35 9.78 2.48 .46 .18 8 Sept. 17 1.0537 13.91 14.66 10.38 10.95 2.12 .45 .18 13 Sept. 24 1.0569 14.74 15.58 11.33 11.96 1.74 .53 .21 20 Oct. 1 1.0614 15.92 16.89 12.75 13.48 1.63 .54 .22 27 Oct. 7 1.0663 17.20 18.34 13.79 14.71 1.53 .61 .24 33 Oct. 16 1.0725 18.82 20.18 15.35 16.46 1.34 .61 .24 42 Oct. 23 1.0716 18.58 19.90 15.01 16.09 1.28 .59 .24 47 Oct. 29 1.0769 19.97 21.50 16.49 17.75 1.22 .57 .23 53 Nov. 4 1.0790 20.52 22.14 16.77 18.08 1.28 .71 .28 59 Nov. 8 1.0755 19.60 21.07 16.39 17.61 1.09 .52 .21 63 nisi 436 MISCELLANEOUS STUDIES Curves of Total Solids, Sugar, Total Acid, Free Acid, and Cream of Tartar. — In order to present the data in a form in which they may be readily studied, graphs have been constructed using time in days as abscissae and the above constituents expressed in grams per 100 c.c. as ordinates. The curves represent the data for 1914, 1915, and 1916. For comparison, curves of the changes in composition of Catawba grapes reported by W. B. Alwood in the United States Department of Agriculture Bulletin 335 have been included. The acid principles have been plotted to a scale five times as great as that used for total solids and sugar in order that the variations in acidity might be more apparent. Discussion of Graphs of Total Solids, Sugar, Total Acid, Cream of Tartar, and Free Acid. — (1) Total Solids and Sugar. The data are more complete for 1916 than for 1914 or 1915, and include the period during which the berries are growing to full size as well as the ripen- ing period itself, during which the rapid increase in sugar occurs. The curves for 1916, therefore, are of more interest than those for 1914 and 1915. In the case of the Burger variety, total solids and sugar remained constant for approximately forty days after the tests were started. There was then a slight rise in these components for a period of about ten days. From that point on the rise in total solids and sugar was very rapid and fairly uniform. The behavior of the Cornichon was very similar. The Muscat began ripening about ten days earlier than the Burger and Cornichon, and proceeded much more rapidly up to about the ninetieth day after the experiment was started. There was then a slowing up in the increase in total solids and sugar corresponding to the period of over-ripeness. This slower increase in total solids is also evident in the curves for Emperor, Muscat, Sultana, and Tokay for the 1915 season, and would undoubtedly show in all cases if the observations were continued sufficiently. The effect of the season upon the rate of ripening is shown by a comparison of the Cornichon and Muscat varieties for 1915 and 1916. All varieties ripened more slowly in 1915 than in 1916, resulting in steeper curves for 1916. However, owing to the fact that sampling was started later in 1914 and 1915 than in 1916, the curves for the former two years show only the changes taking place during the latter half of the ripening period. No very close comparisons therefore can be made of the three years. The Catawba reported by Alwood, and for which curves appear [116] CHEMICAL COMPOSITION OF GBAPES 437 CROP* 9/4- x. & lartanc. G< -Jfn.i XX, Cream efTgffa. ^ /o E.V 3t /Or/ari'c Tar far IQOCJL. 2+ £C+_ 13 JtO Fig. 1 — Malaga first and second crops, 1914. [117] 438 MISCELLANEOUS STUDIES nihlfa4r«* / ht aad-Lj-eaaL XV- &^ ZO&. 15 ft (A 10 5 V m of Taffor Fig. 2 — Tokay first and second crops, 1914. [118] CHEMICAL COMPOSITION OF GBAPES 439 COrfN/CjJON /? = Tfitnlflr.J Tc/rfa fe: an of of d ^in-tar <3rr?3 /OOd- ft &0 18 16 \\ s IX 13 #4 50 36 TIMC IN OfF/5 60 66 Fig. 3 — Cornichon and Emperor, 1915. [119] 440 MISCELLANEOUS STUDIES i Kb a *7. it K)& 6 7x ^F7 30 55 IN Fig. 4 — Malaga and Muscat, 1915. [120] s CHEMICAL COMPOSITION OF GKAPES 441 to*. to K /<3 &f 30 36 -f/C" -73 tO 66 "-Total, \UL7QNft of ~fertir Gm Per /dO tt 2C4- «L. It 10 & 6 _&& e /*> TO #* T/M£ IN D/?y S Fig. 5 — Pedro Zuinbon and Sultana, 1915. [121] 442 MISCELLANEOUS STUDIES ~IZ 73 T& 70 3T Ifll Fig. 6 — Sultanina and Tokay, 1915. 66 [122] CHEMICAL COMPOSITION OF GSAPES 443 TIME IN DftYS Fig. 7 — Burger and Cornichon, 1916. [123] 444 MISCELLANEOUS STUDIES JO "iv TIME IN o/rys Fig. 8— Muscat, 1916. Fig. 9— Catawba (U. S. Dept. Agric. Bull. 335). [1241 CHEMICAL COMPOSITION OF GRAPES 445 in figure 9, ripened more slowly than the Vinifera varieties. For example, during a period of fifty days, the total solids increased only 4 per cent. It can not be said from the data at hand whether this slow ripening is due to the conditions under which the grapes were grown or to the variety. By reference to figures 1 and 2 it may be seen that the general form of the ripening curves is the same for the first and for second crop. In one case, the Malaga, the curves are almost identical for the period common to both, i.e., from 10.6 Bal. to 26.3 Bal., showing an equal rate of ripening. In the other, the Tokay, the curve of the second crop, from 18.2 Bal. to 24.6 Bal., is much flatter than that of the first, indicating a rate of ripening with the latter of about two and a half times that of the former. This difference can be accounted for by the cooler weather during the time the second crop Tokay was ripening, which was about ten days later than in the case of the second crop Malaga. The slower ripening is probably due both to the direct effect of the cool weather and to the decreased activity of the leaves at lower temperatures. (2) Changes in Total Acid, Cream of Tartar, and Free Acid. Owing to the fact that the analyses were started in 1914 and 1915 after ripening had commenced, the curves for these years show a decrease in acid throughout the period of the tests. In 1916, however, a rise in total acid occurred during the growing stage, as shown by a rise in the curve during the first thirty days of the experiment. Although this rise is not very large, it is quite definite, and occurs in all three varieties tested. The rise was most positive in the case of the Muscat grape, and amounted to .67 per cent acid as tartaric. From the point of maximum acidity, the total decreases slowly until the period of rapid ripening sets in. The total acid then decreases very rapidly for a time and more or less in proportion to the increase in total solids and sugar. As the grapes near maturity, the rate of de- crease of total acid becomes less and the total remains practically constant after the grapes have reached maturity. The cream of tartar in general increases very slightly during the periods of growth and ripening. The increase in total acid during the first stages of growth is due to increase in the free acid. Since the cream of tartar remains almost constant throughout the ripening period, the curve of the free acid is practically parallel with that of the total acid. As the grapes approach maturity, the cream of tartar calculated as [1251 446 MISCELLANEOUS STUDIES tartaric acid approaches the total acid, and in one case, (Musct, 1916), actually became equal to the total acid, indicating that in this instance no free acid remained. Second crop grapes were found to be higher in free acid than first crop grapes of the same total solids and sugar content. The Catawba grape grown under eastern conditions (fig. 9) exhibits rela- tively high free acid. Alwood6 has found this free acidity in eastern grapes to be due largely to malic acid. No attempt was made in the analyses of the California samples to identify the various acids making up the free acidity which was calculated as tartaric acid. Mean Differences Between Total Solids and Sugar. — The following table contains figures representing the differences between total solids and sugar at the various percentages of total solids indicated at the tops of the columns. The data represent a range of total solids from 5 per cent to 30 per cent. The figures were taken from the data reported in tables 7 to 9, and represent several varieties of grapes. Only a few determinations of total solids and sugar were available for the lower concentrations (5 per cent to 15 per cent), and therefore the figures for this range may not represent averages so accurately as the figures above 15 per cent total solids. Between 5 per cent and 11 per cent solids, the average difference between total solids and sugar remains practically constant. From 11 per cent to 17 per cent total solids, the mean difference decreases quite rapidly. From 17 per cent to 30 per cent, the difference remains fairly constant. The variations noted after 17 per cent total solids Fig. 10 — Mean differences between total solids and sugar between 5 per cent and 30 per cent total solids. e U. S. Dept. Agric. Bull. 335. [126] CHEMICAL COMPOSITION OF GSAPES 447 t> CO to £ co "2. ::::!: If., to to o> "S 2- .*• " : : : :::::: ?° !*• !^ co co ::::i:i::cocn~3 co en K-» :::::cn co to #. co eo s os g p CO *• CO ^ g b to :;i:i:i!l:booM I I to co «o to en w n> & H co co co eo i_i <->• 45 b\ co CO ......... COCOfcOMg£l J-» co, : i : i i i i i i bo io co w =: g " w to . ...... toeoeototoi-'p g bo en i i i i i i i «o rf»- co bo Ic- oo 1 on OT to .... to co to to to co co to M * o> QO to b ^ co ^ co b w •* » W to i w to ..... tO to tO tO CO CO tO HI ? ^ bo ~j iiiiiio-vjbo-vicocoto00 rf^. ^ M P ^ to ,_, . cotocotototocotoeototoi-' 2. bo H-> ocoto«ob>: M "£' > h-> i co !*>. o bo rf>- If*. J-i ^ to •<» en ° n' t" to ,_, *• to to to to to to to to to co j-i to '-q to o to en «o «o co rf». to «o co J-" ^ M 5? to . . co to co to to to to to co to to £. j^ ^i iib^bbobjbobsenbjb10 os 2. o to ;>;;K>COCOtOtOCOrfk.tOt3aQQ bj to i:i:-4bb»b>rf^btOMw to g o to ,_, ...cototOMbotocotototoS. n rik. i en en ^ «o bo o> en bi to *" g co •» to . . co to to to to to to to M 5' co co ::::rf^£to>>ffctocnO)Cn St ^ to ....... to to to to to to ff to t> to co to to to _to to g. b» en iiiJ^.'h-'enenco^iQ oo «> tO . . ; ; ; ; ; • JO tO tO g S, en co iiiiiiliiitkOkfc n o 8. to to to to «o bo co ; ; •;;:;;: bo bo bo • ^ ••••;:::: .M ?» -10 o co eo :::::: co >-> «o 448 MISCELLANEOUS STUDIES was reached are probably within the experimental error. The large difference between the total solids and sugar noted during the first stages of ripening is no doubt due to the high acid content of the unripe grapes. The fact that the difference remains fairly constant after the grapes have become mature is to be expected, because the cream of tartar, total acid, and protein remain fairly constant as maturity is approached and during the periods of maturity and over- ripeness. • 6 I- Van'af/oa /a Thr A/oft os /OOcc go 3o •TO oo oo /o ov yo /oo /TO Fig. 11 — Variation in non-coagulable protein content for three varieties, 1916. Protein. — The total nitrogen content of the various samples was multiplied by 6.25 to convert it into its protein equivalent. Owing to the fact that the samples were sterilized by heat and filtered before analysis, the figures represent only the protein not coagulated by heat. The curves show that there is a slow increase in protein content during growth and ripening and the greatest increase occurs during the period of most rapid increase of sugar and most rapid decrease of acid. The increase amounted to about .2 per cent in the case of the Muscat and .6 per cent in the case of the Cornichon. The increase seems to be quite definite, although the protein curves are not so regular as those of total solids, sugar, and total acid. [128] CHEMICAL COMPOSITION OF GEAPES 449 SUMMARY OP CHANGES IN MUST OP GRAPES DURING GROWTH AND RIPENING OF BERRIES 1.. Total Solids.— The total solids remain fairly constant during the period of growth, corresponding to the period between setting of the berries and the time at which the berries have reached almost full size but are still hard and green. From this point on, there is a rapid increase in total solids due to increase in sugar. After the period usually considered as full maturity is reached, the increase in total solids is slow. The question may be raised as to whether this last increase is due to an actual synthesis and secretion of sugar or other solids, or simply to evaporation of water. The fact that there is no change in the curve of the acid decrease at this time indicates that the same processes are continuing and that the increased Balling degree represents an actual increase of solids. This view is fortified by observations regarding the increase of weight of solids during the ripening of raisin grapes. It has been shown that the weight of dried grapes shows a continuous increase up to the highest degree observed, 28.75 Balling.7 2. Sugar. — The total sugar during the growth period comprises only a small amount of the total solids. During ripening, the sugar- rapidly increases and then constitutes a much greater proportion. During ripening, the sugar curve follows the total solids curve closely. It is more or less the mirror image of the total acid curve multiplied by five, i.e., increases as the acid decreases. 3. Total Acid and Free Acid. — During the early stages of the growth of the berries, the acidity increases owing to an increase of free acid. This is a fact that the authors have not found mentioned in the literature. During ripening, the total and free acid rapidly decrease. After maturity is reached, the decrease is very slow. 4. Cream of Tartar. — There is a very slow, but usually fairly defi- nite, increase in cream of tartar during ripening. This increase is very much less than the decrease in free acid, and therefore can not account for any great part of this decrease. 7 Bioletti, Frederic T., Relation of the maturity of the grapes to the quantity and quality of the raisins. Proc. Inter. Cong, of Viticulture, San Francisco, 1915, pp. 307-314. [1291 450 MISCELLANEOUS STUDIES 5. Protein. — The protein not coagulated by heat increased defi- nitely during growth and ripening, although the increase was not so regular nor so marked as the increase in sugar or the decrease in total acid. 6. Difference Between Total Solids and Sugar. — This factor re- mained constant for the lower percentages of total solids, decreased during the rapid ripening stage, and remained constant through maturity and over-ripeness. [130] X Q 111 California. University Miscellaneous studies in agriculture and biology PLEASE DO NOT REMOVE CARDS OR SLIPS FROM THIS POCKET UNIVERSITY OF TORONTO LIBRARY