330 Report of the Entomologists of the 



past. Two tubercles, nearly white with dark colored tips, are 

 conspicuous on the lateral margins of the first two abdominal seg- 

 ments. At the tip of the abdomen is a disc covered with a sticky 

 substance which is used both as an aid in crawling about and to 

 hold to the support when necessary. This is especially true with 

 the newly-hatched larva:. Its chief office, however, appears to 

 be as a means of attaching the larva: to the leaf when about to 

 pupate and to hold the suspended pupa until the beetle emerges. 

 The larva: are mature in about two weeks. 



Habits of the larva. — The newlv-hatched larva 1 remain for a 

 few hours crawling about over the empty egg shells, but soon 

 settle down in the immediate vicinity and begin gnawing through 

 the epidermis to feed on the soft tissues beneath. They feed side 

 by side for three or -four days, finally separating to feed independ- 

 ently on different parts of the leaf. As they grow older and 

 stronger they devour the entire leaf with the exception of the 

 midrib and larger veins. (Plate XX, Figure 1.) 



In several cases under observation the eggs had been placed on 

 old leaves and the young larva:, not finding tender food, migrated 

 to the tips of the shoots to feed on the tender leaves and bark thus 

 causing the same injury as the beetles. 



The larva: are full grown in from 10 to 15 days and, after re- 

 maining comparatively inactive for a day or two, prepare for pupa- 

 tion. Plate XX, Figure 2, is from a photograph of a larva, 

 natural size, and enlarged.' 



Pupation. — Pupation takes place above ground. When about 

 to pupate, the larva attaches itself to the leaf by means of the 

 sticky disc at the tip of the abdomen and allows its body to hang 

 down. The head is gradually bent forward and the legs drawn 

 up to the body. The transformation from the larva to the pupa 

 takes place in a few hours. The pupa is retained in the larva 

 skin. 



The pupa. — The pupa: are familiarly known among the willow 

 pupated growers as " hangers." Usually all of the first brood 

 pupate by June 10. The pupae are attached promiscuously to the 



