7 
Puant Lice Ingurinc FouIaAGE AND FRuIT oF THE APPLE 685 
The mature stem mothers are more easily separated than are the nymphs, 
tho the color markings vary considerably with each species. The typical 
forms, drawn to the same scale, are shown in Plates XIX—XXI, and 
the antenne in figure 112. 
Aphis pomi undergoes very slight changes in color. The mature stem 
mother is bright yellowish green (Plate XIX). The head is brownish, 
Fic. 112. ANTENNAE OF MATURE STEM MOTHERS 
A, Aphis pomi; B, A. avenae; C, A. sorbi. All drawn to same scale 
tending toward almost black in some cases. The cornicles, the tips of 
the antennae, and the cauda are black, showing in marked contrast 
to the remainder of the body. 
Aphis sorbi varies considerably in color markings. The typical form 
is shown in Plate XX. The color is generally a purplish brown, inter- 
mingled with greenish on the dorsum. The whole body is covered with 
a fine white pulverulence. There is generally a reddish brown area 
between the bases of the cornicles. The cornicles and the antennae, 
except the basal segments, are black. 
