456 The Ohio Naturalist. [Vol. VI, No. 4, 



A small hoptree {Ptelea trijoliata) immediately beneath the 

 webs in the walnuts was injured but very little, the worms 

 having a decided aversion for it. 



Feeding. — My observations in this direction clearly show that 

 the worms feed but little if at all during the day. At night they 

 leave the nests, or thicker parts of the webs, and move about 

 freely. Some will even leave the protection of the thinner parts 

 of the web and feed unprotected except by the darkness. (I do 

 not mean to assert, however, that there were no threads of silk 

 leading back from the worms to their web.) 



Growth and Moulting. — By actual measurement of worms in 

 a certain brood I found that they increased in length about one- 

 fourth of an inch in twenty-two davs, i. e., they increased in 

 length from one-fourth to one-half inch. At that rate it would 

 take about two months for a worm to mature, which appears to 

 be about the time required at Cedar Point. 



The observations that I succeeded in making upon moulting 

 give me twelve to fifteen days as the interval, the interval from 

 birth to the first moult included. Allowing five moults per 

 season, this would again give us about two months for a worm 

 to become mature. Mature worms probably average from 

 three-fourths to one inch in length. 



The heads moult first, the skin of the head drops off, and 

 the worm then crawls out of the opening. The thorax rarely 

 splits dorsally. 



Other Observations. — I have previously remarked that a 

 brood may divide, each part building a new nest. This I actually 

 observed in several instances. Again, two broods may unite 

 into one brood or a brood may desert its old nest and build a 

 new one. 



In one instance I cut out a nest while the worms were out 

 feeding. Upon their return at daylight they wandered about 

 aimlessly for a while, when one portion settled down and formed 

 a new nest, while the rest returned to an empty nest nearby from 

 which a ])art of the brood in question, a double brood, had come 

 some days before. 



Of three nests cut out and placed upon the ground near some 

 bushes, the worms of one nest were back upon the bush in a new 

 web the morning of the second day, while those of the other two 

 nests gradtially disappeared and apparently migrated to the 

 bushes. 



The appreciable economic loss from the webworm is prob- 

 ably not great, and but few trees are ever endangered; except 

 small trees, which latter may easily become denuded of all their 

 foliage by one or a few broods. 



Biological Hull, (). S. U... Columbus, December 5, 1905. 



