SUBFAMILY APHINAE 91 
Collections. On leaves of Populus sargenti, P. angustifolia and P. sp. Colo- 
rado: Fort Collins, Aspen, Eckert, and Steamboat Springs. Utah: Morgan, 
Tooele and Pinecrest. Fundatrices March 30 and April 2, apterous viviparae 
April 20 to July 23, alate viviparae April 20 to July 20, sexuales Oct. 10 to 23; 
fairly common. 
Type. U.S.N.M., No. 41972. Paratypes, Colo. Agr. Exp. Sta. Collection. 
Fig. 98. Chaitophorus populellus 
Chief Distinguishing Character. Length of III (longer than unguis), length 
of V (1.5 - 2 times base of VI, length of unguis (2 - 3 times base of VI), number 
of secondary sensoria on III (fewer than 9) and their arrangement in a single 
row, absence of sensoria on IV and absence of distinct dark bands on the abdo- 
men of the alate vivipara. 
[Genotype Chaitophorus populi (Linnaeus) ] 
Aphis populi Linnaeus, 1758:453. 
Aphis populeti Panzer, 1801:6. 
Chaitophorus popull, Koch, 1854:12; Buckton, 1877:140; Theobald, 1929:10. 
Fig. 99. Chaitophorus populi 
