90 APHIDS OF THE ROCKY MOUNTAIN REGION 
Subtribe Chaitophorina Baker 
Baker, 1920a:33. 
Characters. Frontal tubercles lacking. Body, legs and usually antenna with 
numerous long hairs; hairs simple, spinelike. Cornicle truncate, length never 
greatly exceeding diameter at base, reticulated on distal portion (except Hoplo- 
chaitophorus). Anal plate rounded or indented, never divided. Cauda rounded 
or knobbed, never elongate. Fore wing with radial sector distinct, media twice- 
forked. Living in colonies; sluggish in movement. 
Key to Genera of Chaitophorina 
is Cauda knobbed \...00..-2-. 2 A Se SE ere 2 
me | \Cauda:semilunar® broader than’ lors (1,943) cece ence eee Periphyllus 
2, Antenna’ five-segmented (p. 103.) <2 -2sckiekscccelees cece c ethos pean aceene eee pene ee Sipha 
Antenna Six*segmrented! 2b si.2i. 20.5 25. coe gnecet eas teep sdcsbee nase ent eeteons ead area coe 3 
3. Cornicle reticulated; anal plate rounded or merely emarginate (p. 90)............ Chaitophorus 
Cornicle not reticulated; anal plate indented (p. 93)...--.----..---:c-cccceeeeeee Hoplochaitophorus 
Genus Chaitophorus Koch* 
Koch, 1854:1; Baker, 1920a:33. 
Characters. Frontal tubercles absent. Antenna six-segmented, with cir- 
cular or oval sensoria and bearing prominent hairs, unguis twice or more times 
as long as base of VI. Hairs simple, usually spinelike, numerous on body. Cor- 
nicle truncate, hardly longer than broad, reticulate distally and imbricated 
proximally. Cauda knobbed; anal plate rounded or indented. Fore wing with 
media twice-branched. Male either apterous or alate. Ovipara apterous. 
Genotype (fixed by Gerstaecker, 1856:202), Aphis populi Linn.* 
Key to Species of Chaitophorus 
1. Sensoria on III in alata, arranged in a single row, not more than 10 in numbet.................. 2 
Sensoria on III in alata arranged in irregular double row, 9 or more : 
Cusually 12) in number: 2x5, Rieti tae dees Perec 3 
2. IV hardly ever exceeding .15 in length; sensoria on III in alata 8-10, never 
with green circle on dorsum. On Salix (ps 92) 5 ce ee viminalis 
IV exceeding .15 in length; sensoria 2-7 on III in alata; with green circle 
on-dorsum, -On Popultis (pe SO) eit eae ee ere populellus 
3. ..Sensoria absent on 1V of|alata’(pi91)) 24 See ee eee popult 
Sensoria usually present on IV of alata (p. 92) ......2..........: EER ERR SA! 8) populifoliae 
Chaitophorus populellus Gillette and Palmer 
The Clear-winged Cottonwood Leaf Aphid (Plate III, 10-12) 
Chaitophorus populella Gillette and Palmer, 1928:15 and 1931:917. 
Fundatrix. Body length 2;hind tibia .50-.60; antenna .72-.90, III .254.312 9) Veetso-1) 
V .11, VI .08+.17-.20. 
Apterous Summer Vivipara. Light green to yellowish with darker green circle on dorsum 
of abdomen connected by lines to lateral margins of abdominal I, IV and VII; legs pale, tarsi 
black. Body length 1.5-2; hind tibia .50-.70; hind tarsal II .12; antenna .95-1.4. Hairs on body 
stout and pointed, .08-.10 long, fairly numerous; on antenna finer, .04 long; on hind tibia .06 
long moderately numerous and erect. Rostral IV+V .12 long and attaining about 2d coxa. 
Alate Vivipara. Same in color and measurements as apterous vivipara except faint, dusky 
bands on abdomen, green markings coalescing on sides leaving pale yellow circle on dorsum of 
abdominal II, III and IV and around cornicle bases; wings hyaline. 
Ovipara. Apterous. Measurements same as apterous vivipara. Hind tibia moderately 
swollen and covered with scattered sensoria. 
Apterous Male. Head and thorax black; abdomen dark green with blackish dashes and 
lateral areas on each segment. Body length 1.2; hind tibia .50-.60; antennal 1.1-1.4. 
Alate Male. Body length 1.5-2.0; other characters as in apterous male. 
*The status of this generic name is in question, pending an opinion by the International 
Commission of Nomenclature to whom a petition has been submitted asking that 
Chaitophorus be made nomen conservanda and requesting the setting of a more suitable 
genotype. The present genotype Aphis populi Linnaeus varies from Koch's concept of 
the genus, since Linnaeus described it ‘‘cornicula nulla.’’ Linnaeus’ description agrees 
with Asiphum tremulae DeGeer and would bring about the replacement of Asiphum 
by Chaitophorus, placing the latter name in a concept totally disagreeing with Koch’s 
clear description of the genus. 
