150 



INSECTS AFFECTING SHADE TKEES. 



body is bluish-black, with the wings transparent and 

 their veins yellowish-brown. 



The oviparous females congregate for the purpose 

 of depositing their eggs in one or a few places on the 

 tree, where they cover the bark with them (Fig. 76). 

 The egg (a) is about one-twentieth of an inch long 

 and oval in form; when first laid it is covered with 

 a liquid which on exjiosure to the air dries into a 

 thin, grayish, irregular covering, suggestive of felt. 



Remedies. — Spray with kerosene emulsion ; cut 

 off and burn the limbs on which the eggs are laid. 



The Toothed Willow Aphis. 



Lachnus dentatus. 

 This is the largest of the aphides affecting the 

 willow, being in fact one of the largest known species 



Fig. 77. Toothed Willow Aphis, viviparous female : a, side view; 6, back view. Magnified 



of this family. The wingless forms are one-fourth 

 of an inch Ions;. Its life-history is much like that of 



