THE CANADIAN ENTOMOLOGIST. 'I'll 



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 this 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 exhausted. 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. When 

 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 were 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 occupied that which it had not begun. Some days 

 after all had apparently retired for the season, one came out and wandered 

 uneasily about, but a few hours later was found to have returned to its 

 case and was seen no more. 



There 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 fatiguing, 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 wrong 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 construct another. The 

 larva? finally entered the cases head first, their bodies contracting in 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 the natural state the case of A rthemis is constructed from the 

 leaf on which the caterpillar began its existence, whether willow or aspen. 



