192 THE CANADIAN ENTOMOLOGIST. 



of June. If, however, any of the last brood of larvae, instead of at once 

 beginning hybernation, incline to feed for two or three weeks, there is 

 plenty of time before severe frosts come to do so and reach the third 

 moult, at which time, in all five-moulting species that I have experimented 

 on, the hybernation occurs, if at all. In such case the larvae would also 

 awake in May, and would reach the butterfly stage two or three weeks earlier 

 than the 25th of June. If any of the summer brood of larvae hybernate 

 after their third moult (a fact which I had no opportunity to establish), 

 then the larvae of both broods would awake at the same time and become 

 butterflies at the same time, making the summer brood. It is to be 

 observed that the several stages of the same brood of larvae do not occur 

 in exactly the same periods of time. From eggs laid on the same day, by 

 the same female, some of the larvae hatched will reach chrysalis several days 

 before others. In the larger Argynnis there will be such a difference, 

 amounting to two or three weeks. Therefore some of the larvae which 

 hybernate at the third moult may be retarded so that their butterflies shall 

 emerge contemporaneously with those which proceed from the larvae that 

 hybernate as soon as they leave the egg. The case is parallel with that of 

 Phyciodes nycteis and with that of Apatura celtis, both double-brooded species, 

 both discovering larvae from the summer brood which hybernate when half 

 grown, while a part of the brood go on to chrysalis and give the fall brood 

 of butterflies, these again producing larvae which also hybernate. (In 

 both these the last hybernation begins after the larva is half grown, the 

 third moult in nycteis, the second in celtis.) Mr. Scudder has made a 

 hypothetical case which is precisely the actual case that- 1 have set forth 

 above. He says : " Should the season be so long that the second brood 

 could lay eggs, the caterpillars would then be forced to hybernate as those 

 of the aestival series and become members of that series the next year. Thus 

 the vernal series would 'continually feed the aestival" &c. Moreover, in no 

 species do the several preparatory stages of its members run even. On 

 the contrary, in any, whether single or double brooded, there will be 

 found by different females eggs freshly laid, eggs ready to hatch, young 

 larvae and mature larvae, all at the same time. By this means there is 

 kept up for a long period, often for weeks, a succession of newly emerged 

 butterflies of the same brood, and the newer and older are constantly 

 mating. On one day in September of this year I cut a branch of Wild 

 Senna (cassia), on which at the moment were newly laid eggs of Terias 

 nicippe, larvae in every stage of growth, and a butterfly of the same species 

 just emerged and still resting on the empty shell of its chrysalis. 



