THE CANADIAN ENTOMOLOGIST. 



third moult, and there was not a thread of a web.* The larvae of thaws are 

 sluggish, and a pretty sharp jar is necessary to cause them to drop from 

 the leaf This they do in a coil, and their bristles effectually protect them 

 from all harm. 



When about to moult, the larvrebred by me ceased feeding, and collected 

 in groups on the covers of the glasses in which I usually kept them, resting 

 for about 36 hours. The body contracted, and as the time for, the moult 

 drew near, the skin became glassy as it separated from the newly formed 

 skin beneath. The spines and bristles of the new skin lie folded down 

 and back, and as the old skin, after splitting behind the head, is shuffled 

 past the successive segments, the spines and pencils of hairs suddenly 

 spring up, and the latter instantly become divergent. For some moments 

 the old mask adheres to the new face, but the larva presently proceeds to 

 rub it off with its feet. When the larva prepares for chrysalis, it spins a 

 button of white silk, and hangs suspended for about 24 hours, its position 

 being nearly circular. 



As I have shown, iharos is polygoneutic in West Virginia, digoneutic 

 in the Catskills, of New York. In a high latitude, or at a high altitude, 

 we might then expect to find it monogoneutic, and restricted probably to 

 the winter form marcia. And this is precisely what does occur in the 

 island of Anticosti (about lat. 50°) and on the southern coast of Labrador 

 opposite. Mr. Couper, who collected in 1873 on the island, informs me 

 that tharos is a rare species there, though he saw it in localities 100 miles 

 apart ; that he saw no examples later than 29th June, from which date 

 " it disappeared " ; and adds, " I do not think any of the diurnals on 

 Anticosti or in Labrador produce a second brood." • When he left, 27th 

 July, " the weather was becoming cold and very few butterflies of any sort 

 were to be seen." Also, " the summer temperature of Southern Labrador 

 and Anticosti are about the same." Of tharos from Anticosti Mr. Couper 

 has sent me 14 males, 8 females. Of these males, all are var. D ; of the 

 females, i is var. C, 7 var. D. With these also came 1 1 males, 2 females 

 from Labrador, all of same variety, D. All these examples are of reduced 

 size, as might be expected from so cool a region. 



Dr. Weisman states (See Can. Ent., Vol. vii, p. 232), that Dorfmeister 

 was led by his experiments on the effect of cold on the pupae of butter- 



* I found last summer that nydds larva; will eat asters as readily as Actinomeris 

 squarrosa, which hitherto I had fed them on. 



