PLANT LICE. 195 
the buds; they are very minute, oval, shining and black, but 
when first laid they are of a light yellow or greenish color. Early 
in spring the young lice hatch, and reaching maturity in ten 
to twelve days, they commence to give birth to living young at 
the rate of two each day. The young locate as closely to the 
parents as they can, and also become mothers before very long. 
The young lice, when newly born, are almost white, but soon 
become of a pale, dull, yellowish-green color. The insect is 
shown in Fig. 156. As far as Minnesota is concerned the 
migration to wheat fields has not yet been observed. 
Fic. 156—Aphis mali Fab.; winged viviparous female, apterous viviparous 
female. After Bruher. 
Aphis malifolie Fitch is perhaps only a variety of the above 
insect. It is, however, black. 
In Fig. 156, Plate XII, is illustrated another plant-louse 
infesting the apple; it is Aphis sorbi Kaltenbach of Europe. 
Aphis prunifolie Fitch (prunt Thos.). (The Plum-tree Plant- 
louse). 
This insect resembles the Apple Aphis,and is sometimes rather 
common. It infests the underside of the plum leaves, puncturing 
them, and if at all numerous, curling and twisting the same. 
When first hatched the young lice are of a whitish green color, 
but as they grow older they become a deeper green, and when 
mature they have a shining black head and thorax, with a 
pale green abdomen, marked with a row of dots; the winged forms 
possess dusky wings. 
