370 Report of the Entomologists of the 



covered with long gray hairs. When first hatched they swarm 

 upon the egg mass. If other food is not plenty they will eat the 

 glue that covers the eggs. About 100 caterpillars hatched in a 

 cage in the laboratory subsisted for 6 days upon no other food 

 than the frothy glue that protected the eggs from which they 

 hatched. 



The caterpillars spread a thread of silk wherever they go. The 

 young when disturbed will drop suddenly, suspending themselves 

 by means of a silken thread in much the same manner as the 

 canker worm. This habit of the young is not common with the 

 mature caterpillars. 



Soon after hatching, if food is plenty, they select a place to 

 build a nest. Usually the nest is built by only one colony of cater- 

 pillars, but if two masses of eggs are placed near together the 

 caterpillars from both masses may unite in building a single nest. 



From observations on several nests it appears that if the weather 

 is favorable and food plenty the caterpillars are ready to begin 

 building the nest within about two days after hatching. The 

 place selected is usually tlje angle formed by some branching limb 

 near the egg mass. The larvas are social, living together within 

 the nest and feeding together upon the leaves. 



The number of molts. — Some of the caterpillars kept in breed- 

 ing cages molted 5 and a few 6 times. The first 2 molts 

 take place within 7 or 8 days after hatching and the third 

 about a week from the second. The fourth and fifth take place 

 within the next 2 or 3 weeks and the sixth, when it occurs, 

 4 or 5 days later. The color markings begin to show prominently 

 after the first molt. 



Growth and feeding habits. — Most of the caterpillars under 

 observations were fully grown and ready to pupate about 6 weeks 

 after hatching. They were extremely voracious especially when 

 about two-thirds grown. It has been estimated that when at this 

 age a single caterpillar will eat two fair-sized apple leaves in a 

 single day. A nest of 200 caterpillars all eating at this 



