456 
The Ohio Naturalist. 
[Vol. VI, No. 4, 
A small hoptree (Ptelea trifoliata) 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 days, 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 actual!}’ 
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 part 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 gradually 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 H.all, O. S. U., Columbus, December .5, 190.5. 
