106 MANUAL OF V EC ET A liLE-d AHDEN INSECTS 



Fig. 66. — Wiiijuilo.ss vivipnrou.s 

 female spinach aphis (X 11). 



are then greenish with the liead, thorax and a hirge spot on the 

 abdomen hhick. These winged forms leave the tree and fly 

 to their various her})a('eons food plants where they found eolonies 

 of young. When the lice have survived the winter on weeds 



or vegetables, rei)roduetion is resumed 

 as soon as new growth starts in the 

 s})ring. They multiply rapidly and 

 the plants soon become covered with 

 the lice. The wingless forms found 

 oil the summer food plants have the 

 body a uniform greenish yellow, 

 without the darker lines found on 

 the forms on the peach or i)lum 

 (Fig. ()6). When the })lant becomes 

 crowded, winged forms (Fig. 07) are 

 produced which migrate to new feed- 

 ing grounds. The insects are most destructive to spinach 

 late in the season when the cooler weather i)revents the rapid 

 multiplication of their ])redaceous and parasitic enemies, 

 although they may become troublesome at any time. In the 

 fall some of the winged females return to the ])each, ])lum ( r 

 cherry, establish themselves 

 along the veins on the un- 

 derside of the leaves and 

 give birth to true or ovipa- 

 rous females. The latter are 

 usually of a pinkish color, 

 similar to the stem-mothers 

 of the preceding spring. 

 After ])airing with the 

 winged males, they deposit their eggs in the axils of the buds 

 and in crexices of the bark. The eggs are small, oxal and 

 shining black, and closely resem})le those (5f the conunon green 

 apple aphis. 



Fi( 



— ^^'illgcd viviparou-; fcinalc 

 spinach aphis (X 7^). 



