126 APHIDS OF THE ROCKY MOUNTAIN REGION 
Apterous Summer Vivipara. Large Form. Body length 1.45; antenna .85; hind tibia .83; 
hind tarsal II .11-.14; rostrum obtuse, slender, attaining 3d coxa. Hairs on vertex and antenna 
fine, pointed, sparse, .01 long; on hind tibia sparse, .015-.02 long. Cauda tapering bearing 4 
hairs on each side. Lateral tubercles evident only on prothorax. Small Form. Body length 
1.3; hind tibia .50; hind tarsal II .10; antenna .53-.60; cauda .10 on median line, bearing 2-3 
hairs on each side. 
Collections. On leaves and twigs of Sarcobatus vermiculatus. Colorado: 
Manzanola and Grand Junction. Idaho: Delco and Parma. Utah: Throughout 
northern part of state. Alate viviparae May 18 and in Sept., apterous viviparae 
May 15 to Nov. 10, dwarf apterous viviparae at Grand Junction June 24 and 
Parma July 23; probably not rare but little collecting has been done in locali- 
ties where the host occurs. 
Cotypes. Knowlton, Utah Agr. Exp. Sta. and Colo. Agr. Exp. Sta. Collec- 
tions. 
Chief Distinguishing Characters. Pale blue-green body without markings, 
fact that rostral IV+V, cauda, unguis and base of VI are about the same 
length and cornicle variation, from the same length as the latter parts to 1.5 
times their length. 
Aphis canae Williams 
Aphis canae Williams, 1910:39; Davis, 1911b:11; Gillette and Palmer, 1932b:385. 
Anuraphis canae, Gillette and Palmer, 1928:10. 
Apterous Summer Vivipara. Green with darker mottling, with whitish band on abdom- 
inal I and lighter color around margins of body; head darker; cornicle black; legs pale. Body 
length 1.60; antenna .71-.93; hind tibia .50-.60; hind tarsal II .10; rostrum acute, tip beyond 
hairs compressed laterally, needlelike in ventral view, .06 long, resembling distinct segment 
V, attaining abdominal I. 
Cor IS -25 
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ts 
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Fig. 134. Aphis canae 
Alate Vivipara. Color as in apterous vivipara. Body length 1.24; antenna .82-.92, sec- 
ondary sensoria large, in single row, on III. Cauda tapering, with rounded tip, bearing 3 
curved hairs on each side. Lateral tubercles developed on prothorax and abdominal I and 
VIL 
Collections. On leaves and stems of Artemisia cana, A. filifolia, A. tri- 
dentata and A. longifolia. Throughout region. Apterous summer viviparae May 
17 to Aug. 8, alate viviparae May 17 to July 15; not abundant. 
Cotypes. U.S.N.M., No. 60 and Univ. of Neb. Collection, No. 54. 
This group containing A. canae, A. filifoliae, A. hermistonii and A. oregon- 
ensis, presents a very puzzling series of gradations. No structural differences, 
other than size and proportions of antennal segments and cornicles, were de- 
tected; and no distinct line can be drawn between any of the forms. Neither 
is any definite aid to be gotten from the host species as each form has been 
taken on several species of Artemisia. On the other hand the limits of varia- 
tion represented by the extreme forms make it seem rather improbable that 
only one species is concerned. This is supported by the fact that with but a few 
exceptions, the individuals of a single collection all fall in the same group. 
Since the several species names have been established it seems most advisable 
to the author to hold them distinct until further study proves otherwise. 
