106 APHIDS OF THE ROCKY MOUNTAIN REGION 
Egg. Newly-laid, pale olive-yellow; later, black; naked. Size 1.25 by .50. 
Collections. On bark of Salix sp. Generally throughout region. Fundatrices 
April 2 to 18, alate and apterous summer viviparae April 2 to Nov. 6, sexuales 
Oct. 2 to Nov. 13; extremely common and abundant. 
Cotypes. Univ. of Minn. Collection. 
This form differs from P. populifoliae as follows: Shorter cornicle (.25-.35, 
about the same as unguis, instead of .33-.40 and longer than unguis), shorter 
antenna (1.5-2 instead of 2-2.25). These two forms are very closely related and 
really rank intermediate between P. bicolor and P. populifoliae Fitch, as de- 
scribed by Baker (op. cit.). The unguis in summer viviparae of Colorado 
examples from Salix hardly ever attains twice and sometimes hardly more 
than 1.5 times length of base of VI and varies from once to 1.5 times base in 
Colorado examples from Pcpulus, but is same length as base in fundatrices of 
both forms. There is sufficient overlapping so that no distinct line can be 
drawn and very few reach the extremes given by Baker (op. cit.) for the two 
species. Possibly these forms are but variations of a single species. At present 
it seems best to determine the Salix form as P. bicolor and the Populus form as 
P. populifoliae, awaiting biological tests. 
Pterocomma braggii (Gillette and Palmer) n. comb. 
Plocamaphis braggii Gillette and Palmer, 1929a:1 and 1931::930. 
Fundatrix. Same as summer apterous vivipara except as follows: Appendages darker; 
hind tibia shorter (1.27) and antenna slightly shorter (1.50). 
Apterous Summer Vivipara. Yellowish to dusky brown, with blackish lateral areas and 
lighter, sordid tan and powdery intersegmental lines and median line; hairy; appendages 
sordid yellowish brown, blackish on tarsi, tips of tibiae and antennal I, II, V and VI; cornicle 
pale or concolorous with body. Body length 2.5-3; hind tibia 1.5-1.8; hind tarsal II .20; 
antenna 1.5-1.9; cornicle .05-.06. Hairs pointed, numerous; on antenna erect, slightly longer 
than diameter of III; on hind tibia about same length but slightly shorter than diameter of 
tibia; on body .08-.10 long. Lateral tubercles conspicuous on prothorax and all abdominal 
segments except VIII. Ocular tubercle inconspicuous. Cornicle minute, difficult to discern, 
slender, cylindrical, hardly swollen, curved inward, without flange and constricted at opening, 
imbricated. Rostral IV+V .21 long, broadly obtuse; attaining abdomen. 
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Fig. 115. Pterocomma braggii 
Alate Vivipara. Head and thorax blackish; abdomen yellowish dusky brown with black- 
ish lateral areas; appendages sordid to dusky yellowish brown, darker distally; cornicle pale 
yellow-brown and inconspicuous; wings hyaline, fore wing with media once-branched (in the 
4 examples taken), posterior edge of stigma with scattered setulae. Measurements as in 
apterous vivipara. 
Ovipara. Apterous. Color and measurements as in viviparae except body slightly more 
elongate. Venter of abdominal VI, VII and VIII bearing short wax filaments. Hind tibia 
very slightly swollen on proximal half and bearing thinly scattered minute sensoria. 
Male. Apterous. Color same as in viviparae. Body length 2.30; hind tibia 1.20; antenna 
del. 
