412 THE CANADIAN ENTOMOLOGIST. 



fixed in the silk. The chrysalis first appeared through the black skin as 



a white dash in the middle of the second thoracic segment. This slit was 



gradually enlarged by the contortions of the chrysalis, the split running 



down the body very slowly until the head portion was withdrawn from 



the skin. After that, by a continuation of laboured expansions and 



contractions of the body, the skin was gradually worked back until it 



reached the last segment but one of the chrysalis on the dorsal side ; but 

 the head and first segments of the larval skin had then only just passed 

 the tips of the wing-cases on the ventral side. Then the skin was 

 gradually slipped back two more segments on the ventral side, after which 

 the cremaster was withdrawn from beneath the skin and was, evidently 

 with much exertion, slowly pushed up until it reached the pad of silk. 

 Here, immediately it touched the silk, it was worked round and round 

 vigorously, and there was a distinct discharge of a pinkish glutinous liquid, 

 by which the cremastral hooks were apparently cemented into the silk, 

 and which gave a pink tinge to the part where the hooks were attached. 

 I was surprised to see this liquid, and at once asked Mr. Gibson to 

 confirm the observation through a lens, which he did. By the twisting 

 of the body the cast-off skin was now gradually worked off, and the 

 chrysalis continued for about 15 seconds twisting, the cremaster into the 

 silk. The whole operation, from the time the skin burst until the 

 chrysalis was attached to the silk, was 12 and 15 seconds, but the 

 chrysalis did not take its permanent hardened form for an hour afterwards, 

 and the thorax remained white and facelike for some hours. 



As far as we could observe, there was no grasping of the larval skin 

 between the abdominal segments of the chrysalis, but the moisture with 

 which the whole surface of the new chrysalis was bathed seemed sufficient 

 to hold it to the skin and keep it from falling until the cremastral hooks 

 were worked into the silk. 



The larva was one of a belated brood which was collected on 

 Saturday, October 27th. There had been several sharp frosts, and the 

 thermometer was almost at the freezing point when these caterpillars were 

 rescued. The leaves on the willow tree where they were found were 

 mostly frostbitten or ripened to a yellowish colour. When brought into 

 the office, the most of them recovered and fed, but a few were apparently 

 too far starved and died. 



Pupation of those which survived took place from Nov. 5th to i2ih. 



