300 Report of the Entomologists of the 



lias observed the caterpillars disperse toward evening after having 

 remained together during the greater part of the day. When 

 about to molt their usual places for congregating are upon the 

 branches and trunks of the infested trees. The young caterpil- 

 lars are more often found upon the former and those that are near- 

 ing fully growth upon the latter or on the large limbs of the larger 

 trees. Plates XXIII is from a photograph of a group of caterpil- 

 lars, most of which were not more than half grown, upon a limb of 

 a young basswood tree. This photograph was taken at 11 :30 a. m. 

 In the sections of the State where the caterpillars were very 

 abundant they were frequently found together, when preparing to 

 molt, in such large numbers as to completely cover one side of 

 the trunk of a full-grown sugar maple tree to the distance of throe 

 or four feet. Plate XXIV is from a photograph taken at 3:15 

 p. M., of a comparatively small group of caterpillars about two- 

 thirds grown upon a small plum tree in an orchard .near Geneva. 



Bestlessness of the full-grown caterpillars. — After the last molt 

 the caterpillars become very restless, wandering up and down the 

 trunks, along fences, etc., until finally the cocoons are spun. It 

 has been observed that they feed but little during this period. 

 This was also indicated by the colonies kept in our breeding 

 cages. After the last molt they ate but very little, wandering about 

 for three or four days and finally spinning their cocoons in all 

 parts of the cages. 



Number of molts and descriptions. — The number of molts is 

 usually four. A fifth molt occurs soon after the cocoon is spun. 

 The molting periods, with the exception of the first, which was 

 not observed, of a large number of caterpillars confined in breed- 

 ing cages last spring were as follows : The first molt was about 

 May 8, the second May 16, the third May 31. About ten days 

 later part of them molted a fourth time and within three days 

 spun their cocoons. A small proportion of those that molted but 

 three times spun cocoons. The remainder died. This lack of 

 normal development was probably due to insufiicient food as they 

 were accidentally deprived of fresh food for nearly two days be- 



