144 



INSECTS AFFECTING SHADE TREES. 



of a brown, circular, leathery scale, about one-quarter 

 of an inch in diameter, beneath which is a peculiar, 

 fluffy, cottony mass (Fig. 72, a). In the spring there 

 may be found in each of these masses, great numbers 

 (from 700 to 1,000) of small, white, spherical eggs. 

 Early in summer these eggs hatch into young lice, 

 which scatter over the trees, wandering about on the 

 twigs and leaves for a few days, and, finally, fixing 

 themselves upon the lower leaf surface, insert their 

 tiny beaks and suck out the sap. They remain in 



Fig. 72. Maple Bark-louse : a, cottony scales on twigs ; 



b, back view of scale, magnified ; c, ventral 



view of scale, more magnified. 



this position several weeks, when a few of them be- 

 come fully developed winged males. These mate 

 with the remainder, which are females, and soon die. 



