THE CANADIAN ENTOMOLOGIST. 179 



completed by Sept. 25th of the same year. This year, although every- 

 thing is about two weeks behind its usual time, I received two mature 

 larvae July 5th, both of which had unfortunately been killed ; with them 

 came a moth taken the same da\-, whose wings had not expanded when 

 discovered. 



The time from deposit of egg to pupation is about eight weeks, some- 

 times a day or two more, but usually three or four days less, hence these 

 ova must have been deposited before May loth, or before even Colias 

 philodice had appeared. As I know of no Sphinges emerging here before 

 the middle of June, the contraction of the time of growth would be very 

 remarkable in this case, even had the weather been hot, which it has not. 



I have taken this moth (P. nchemon) in May, flying about the early 

 spring flowers in company with Dcilephila lineata, both very ragged and 

 much faded ; this would seem to suggest that P. achemon (and perhaps 

 other Sphinges) exists as it were in duplicate, the September examples 

 hybernating in the perfect state and depositing ova in the spring. A state 

 of affairs possibly instituted by a long, dry and warm season in summer 

 and autumn, and continuing until a severe winter, destroys the hybernating 

 examples, which must also suffer greatly from mice, and their ova and 

 larvcC from late frosts, thus accounting for their rarity. 



This is, I admit, a very weakly supported hypothesis, resting entirely 

 upon circumstantial evidence, as early examples of strong moths like 

 Sphinges mi^ht travel many miles before a strong south wind ; if, however, 

 some collector who has females emerge in September, w'ould dissect them 

 and ascertain how far the ova are developed, the result would probably 

 offer a satisfactory solution as to the probability of occasional or regular 

 hybernations. 



It may be a matter of interest that Pieiis rapce has reached this point 

 in its westward journey. I took one ^ example at Maplewood, imme- 

 diately west of this city, Sept. 8th ; seemed to be more abundant than 

 P. protodice, wliich was flying in the same locality. 



C. E. WoRTHiNGTON, Chicago. 



'■b^ 



DRYOCAMPA RUBICUNDA (fABR.) 



Dear Sir, — 



Mr. Linter, in his "Entomological Contributions," No. 3, has a very 

 elaborate description of this larva, noting, indeed, very minute char- 



