ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 



23 



White-Marked Tussock Moth, Hemerocampa leucostigma 

 (J. E. Smith), fig. 17. — Second in importance to the spring can- 

 kerworm as a leaf eater of American elm, this insect in its larval 

 stage is mainly a pest of city shade trees. The showy caterpillar 

 of the tussock moth begins feeding a little later in the spring 

 than the cankerworm but may develop two generations in a 

 year to make up for the late start. Its body is covered with tufts 



Fig. 16. — Spring cankerworm: A, male adult; B, female adults (wing- 

 less); C, eggs; D, larva; E, pupae. The larva is dark green, brown, or 

 black. (Photographs from United States Department of Agriculture.) 



of long white hairs. Two longer tufts of black hairs provide 

 "horns" at the front, while a single black tuft "flags" the rear. 

 When 5 or 6 weeks old, the caterpillar stops consuming leaves 

 and spins a cocoon on the trunk or a limb of the tree on which it 

 has been feeding, or on a fence or house. Here transformation 

 takes place. From the cocoons emerge winged males and wing- 

 less females. A wingless female, after emerging and mating, 

 lays several hundred white eggs, all glued together in a clump, 



