THE FALL WEBWORM — SNODGRASS. 403 



seen caterpillars at work on outlying structures quit their spinning 

 and gather on the top of the main web where they all stretched out 

 motionless against the surface. Soon the big drops were coming 

 down. The first that struck the tent only created a little commotion 

 amongst the inhabitants, but within five minutes after the rain was 

 comino- down in earnest every webworm had moved to the under sur- 

 face of the tent or to the side away from that toward which the 

 rain was slanted. Only a few took refuge within. After a hard 

 rainstorm the webs are wretched and bedraggled looking things, 

 but the industrious owners proceed with the building of additions 

 or the construction of a new house. 



Sometimes a colony for some reason becomes dissatisfied with its 

 location in a tree and decides to migrate. On such occasions the 

 worms may move a considerable distance, going down one branch 

 and up another, passing an abundance of foliage on the way, and 

 generally selecting the end of a twig as a new building site. In cases 

 of bad infestation, when a tree becomes largely or completely de- 

 foliated, the caterpillars are said to travel all over it in search of new 

 provender or to go off to another tree. During their smaller migra- 

 tions, which the writer has observed, there never appears to be any 

 definite leadership nor any organized progression to a new camping 

 place. A few venturers explore the twig or branch, laying a line of 

 silk that the others eventually follow. Wherever the pioneers halt 

 and begin the spinning of a web there the others finally accumulate 

 and fall to work. 



One writer has described the webworms as nocturnal wanderers, 

 going forth from their homes at night to feed in the open with no pro- 

 tection but the darkness, returning at an early hour in the morning 

 with full stomachs to pass the day resting inside, where they do little 

 if any feeding. Personally I have never observed anything of this 

 sort in connection with the webworms. Those visited at night were 

 always either working on the web or feeding inside just as in the 

 daytime; or, if any were away from it, they were busy weaving a 

 new structure or an extension to the old one. For two seasons I kept 

 colonies in my room where I lived and slept and never did the worms 

 wander from their homes, except in the last stage when they go off 

 but do not return. Out of doors one never sees devastated leaves in 

 the neighborhood of the webs, while the webs are always full of 

 them — sufficient evidence of the feeding within them. The noc- 

 turnal habits and other traits described by the present writer are so 

 characteristic of another species, the tent caterpillar, that one is 

 tempted to believe he did not distinguish between them in the dark. 



The caterpillars of the Connecticut colony that hatched on the 

 15th of June began to appear in the fifth stage on July 9. In Stage 



