( xxxviii ) 



double-brooded, though he had obtained no evidence that 

 it could survive an English winter in the pupal stage, as 

 it is stated to do in the very different North American 

 winter. Pupfe of the summer emergence of Chri/sophaiius 

 pldceas were exposed to temperatures ranging from 80° to 90°, 

 emerging in six days ; and down to 45°, emerging in about 

 eight weeks. In those at the highest temperature the coppery 

 colour was dusky, the spots large and not sharply defined ; as 

 the temperature was lowered, the copper colour became 

 brighter, the black more intense, and the spots smaller and 

 more sharply defined, and the copper band on the hind wings 

 much broader. Some that were iced (33°) for ten weeks, and 

 then plunged into a high temperature, showed most of the 

 features of those which had been throughout at the high 

 temperatures. The results seemed to indicate that the dusky 

 colouring of C. phlceas in Southern Europe, and the varying 

 colour of the American C. Jujpnphlaas, according to the 

 season of its emergence, as described by Mr. Scudder, were 

 in a large measure owing to the temperature to which the 

 individual pupje were subjected. Of E. punctaria he had a 

 large brood of the summer emergence from the same parent. 

 These were subjected to varying temperatures, and showed 

 a gradual disappearance of the conspicuous submarginal 

 blotches, an increase of the sprinkling of dark scales on the 

 ground colour and an intensification of the central line, as 

 the temperature was lowered from 90°, through 70° and 56° 

 to 45°. There was no great difference between those at 

 90°, which emerged in from four to five days, and those 

 at 70^, emerging in from ten to eleven days ; but the 

 difference was considerable in those at 56°, emerging in from 

 twenty-two to twenty-seven days ; and greater still in those at 

 45°, which emerged in from fifty-seven to seventy days ; in 

 these last the blotches had disappeared. A temperature of 

 33° seemed to suspend the physiological changes without 

 much, if any, other effect ; for tliose which were tlius iced for 

 over three months, and then exposed to a high temperature, 

 emerging in from five to seven days, closely resembled in 

 appearance tliose exposed to a similar temperature without 

 having been iced at all. A large number of specimens were 

 exhibited in illustration of the paper. 



