OBSERVATIONS ON HABITS OF FALL WEB WORM. 47 



tion I believe distinctly indicates that the webs serve mainly for pro- 

 tection from enemies during the day. 



I found the caterpillars during July breaking camp at about 7.15 

 p. m., and by 7.30 they were feeding; at 10 p. m. and at 3 a. m. also 

 they were feeding, there being only a few individuals, evidently 

 getting ready to molt, in the nests ; at 4 a. m., daybreak found them 

 homeward bound. Younger broods, below the second moult, were 

 observed to be slower in coming home. Only one observation was 

 made at 3 a. m. and two at 4 a. m. ; between 7 and 10 p. m. frequent 

 observations were made.® 



The black-billed cuckoo was seen feeding upon the worms at differ- 

 ent times. Dr. William E. Kellicott, whose work gave him oppor- 

 tunity to observe the contents of toads' stomachs, kindly consented 

 to make special note of these, in order to determine to what extent 

 the toads at the Point feed upon the webworm. His observations are 

 wholly negative, however, probably because he never used the toads 

 until about twelve hours after collecting, when nothing but the harder 

 parts of beetles, crickets, grasshoppers, and the like could be identi- 

 fied. He expresses doubt that the toads feed much upon the cater- 

 pillars. Riley's bulletin states that the toads fed freely upon the 

 worms. 



GROWTH AND MOLTING. 



A brood of small worms, which I judged could not be over a few 

 days old, was transferred to another cherry tree more favorably 

 located for observation. The twig upon which they lived was cut 

 off and tied to a branch in the new location. It was only after sev- 

 eral days that the caterpillars migrated to fresh leaves, the old ones 

 in the meantime having become quite dry. They did not seem to 

 thrive after that, and during 22 days, the time that they were 

 under observation, they grew but little, if any, in length, as shown 

 by actual measurement. They began to molt in 12 days from the 

 time that they were first observed. Thus it appears that their first 

 molt occurs 12 or 15 days after hatching. Another slightly older 

 brood (on some willows), which measured one-fourth inch (6.25 

 mm.) in length measured one-half inch (12.5 mm.) after 22 days, 

 having thus grown one-fourth inch in that time. This brood be- 

 came mixed with an older brood with which it went to live, so that 

 nothing in regard to its molting could be determined. Another 



a I tried to corroborate these conclusions upon feeding by an examination of 

 the digestive tracts of specimens collected at different times of the day. Thus 

 I dissected specimens collected at 7 and 10 a. m. and at 1 and 5 p. m. Not less 

 than 20 specimens were examined, but little difference was observed except that 

 I concluded that the anterior parts of the digestive tracts of the latter were less 

 gorged. 



