134 



SOME REMARKS ON THE ALLEGED ABNORMAL 

 PECULIARITIES OF ARGYNNIS MYRINA. 



By W. H. Edwards. 

 [Read before the Ent. Sub. Section of the Am. Ass'n, at Cinn., 19 Aug. 1881]. 



In Amer. Naturalist for Sept. 1872, Mr. S. H. Scudder pub- 

 lished a paper entitled "The Curious History of a Butterfly," 

 which reads thus : " Of all American butterflies, Brenthis (Argy- 

 nnis) Bellona presents the strangest history." Again : " In this 

 genus, at least in B. Bellona and B. Myrina, occurs a phenomenon 

 which, so far as I know, is quite unique among butterflies: there 

 are two sets of individuals, each following its own cycle of 

 changes, apparently with as little to do with the other set as if 

 it were a different species ; each set has its own distinct season 

 and thus gives rise to the apparition of two or three successive 

 ' broods ' in the course of the year. At the very end of the 

 season this butterfly will be found laying eggs, which hatch in a 

 few days ; the little caterpillars, after devouring their &^^ shells, 

 refuse further food, and undoubtedly hibernate in this state ; 

 * * * This we will term the aestival series, for by the 

 end of the following June, the caterpillars have attained their 

 growth, and passing through the chrysalis state, emerge as butter- 

 flies about the middle of July; these are the butterflies of mid- 

 summer, continuing upon the wing until the end of September. 

 In this butterfly the eggs are wholly undeveloped at the birth of 

 the female, and in the aestival series are not deposited until Sep- 

 tember; they hatch in from five to nine days, and the young 

 caterpillars, as we have said, pass directly into a state of hiber- 

 nation, making the cycle of the year's changes complete with a 

 single generation. The second set of individuals, which we will 

 term the vernal, hibernates as half-grown caterpillars and pro- 

 duces the earliest brood of butterflies ; these make their appear- 

 ance about the middle of May, although they are occasionally 

 seen earlier; they are hardly common before the end of the 

 month, and are as long-lived as their companions of the aestival 

 series; they do not lay their eggs until the latter part of July or 

 early in August, just when the butterflies of the aestival series 

 are becoming common ; the eggs hatch and the caterpillars grow 

 as usual, sloughing their integuments twice. Beyond this point 

 all caterpillars do not develop alike: some continue in what 

 would appear the natural way; we will first follow them — it will 

 be to their grave ! As caterpillars they eat, as chrysalids they 

 sleep and then appear in September, gay and frolicsome butter- 



