42 



found at Gaueva as late as May 26, and colonies of newly hatched 

 caterpillars were found at various times between, while by May 22 

 large numbers ot caterpillars had reached nearly full size. 



Growth. — Under normal conditions the caterpillars are full- 

 grown within about six weeks, but in case they hatch before the leaf 

 buds of their food plants have burst, their development is retarded 

 by lack of food. Cold or inclement weather soon after the young 

 caterpillars have hatched also delays their growth. Dr. Riley'= 

 states that the newly hatched caterpillars are able to fast fully 

 three weeks and "to withstand any amount of inclement weather," 



Feeding hoMls. — During the first three or four weeks the cater- 

 pillars are gregarious, but as they approach full size, and especially 

 after the last molt they scatter about the tree. During the earlier 

 stages only a portion of the leaf is consumed, but later nearly the 

 entire leaf may be devoured. Weed states'* that ' ' the caterpillars 

 Commonly eat through the leaf in such a way that the outer end 

 drops to the ground," thus causing the insect to be relatively 

 more destructive than if devouring the entire leaf. They feed 

 chiefly during the night, and to a limited extent during the cool 

 of the day. While not feeding they were oftefi seen last season 

 resting in small groups upon the leaves, as shown in Plate 

 II, fig. 2, which is from a snap-shot taken on a very warm day at 

 11:15 A.. M. The nature of the injury to the leaves is also shown 

 in this picture. 



Silk spinning habit. — From th« first the young caterpillars 

 spin a thread of silk wherever they go, but seldom if ever make a 

 true nest. Sometimes a few leaves that the caterpillars have 

 passed over will become covered with silk and attached to adjoin- 

 ing leaves, thus giving the whole the appearance of a rude nest 

 or tent. If disturbed the young caterpillars will drop quickly 

 to the ground. In the bulletin just referred to Dr. Weed reports 

 an observation by Mr. W. F. Fiske to the effect that the young 

 caterpillars when suddenly disturbed while feeding will drop 

 to the ground without attaching a thread. This is also 

 true of the older caterpillars. When congregated upon a twig 

 the young caterpillars are more apt to attach a thread which, 



■sAmer. Ent. and Bot, 2: J62. 



"N. H. Agr. Exp. Sta. Bull 64, pp. 83-84. 



