UMENITIS I. 
thick permanent covering to this gap; which done, it worked back, drawing the 
e < ° es as ^ eiore > ant ^ weaving, till at length the case was complete. (Fio*. i.) 
As it spun, the larva was in a constant state of anxiety about its work, as if it 
foresaw the storms of rain and wind it must be subjected to for many long months 
shut in tins slender house. In closing, it lies along the midrib inside, its anterior 
segments extending over the top, and it moves its head from side to side weaving 
a concave edge. But it often reached far over and added a thread here and there 
where the work seemed to be finished, and it would frequently leave the case to 
inspect the fastenings about the branch, and to weave additional threads there 
as needed. The silk is passed entirely around the branch, and binds both sides 
of the leaf-stem. In weaving at the case the larva would soon become ex¬ 
hausted. I timed one actively at work for ten minutes, and there succeeded an 
interval about as long of rest, the larva lying motionless along the midrib. 
\\ hen at last the case is finished, the larva enters, and rests awhile, but presently 
comes out, runs about examining the stem and the fastenings, then returns_ 
and this scrutiny will be repeated perhaps three or four times. Two larvse 
weie kept in the same glass, each of which had commenced a case and partly 
inclosed it, when I removed one. The other soon began to amuse itself by 
shifting about, trying each case and working at it, and finally completed and oc¬ 
cupied that which it had not begun. Some days after all had apparently retired 
foi the season, one came out and wandered uneasily about, but a few hours later 
v as found to have leturned to its case and was seen no more. 
Iliere was some variation in the mode of cutting the pattern, as sometimes 
work was begun on the side of the leaf instead of at the base. But it always 
resulted in the same fiddle-shaped piece. The cutting was evidently fatiguiim 
from the inconvenient position of body required, the head and anterior segments 
having to be bent sideways, even to a right angle much of the time, and the 
larva frequently rested and shifted its place. It was never found on the wroim 
side of the cut, however, or in danger of falling with the rejected portion of the 
leaf. Occasionally after having begun a case the larva would desert it and con¬ 
struct another. The larvae finally entered the cases head first, their bodies con¬ 
tracting m length and proportionately thickening so as to completely fill the 
upper end of the tube, and allow nothing to be visible from the aperture, while 
over this last the long flap of the leaf soon curved sufficiently to keep out water. 
Probably in natural state the case is constructed from the leaf on which the 
caterpillar began its existence, whether willow or aspen. This is so with Zfisip- 
2 ms.. The ends of the leaves have been eaten away and only the sides need 
s lapmg. But if the residue is insufficient, or for any reason does not answer 
the purpose, the caterpillar moves to another leaf and begins cutting 
O O’ 
