SEASONAL CHANGES AND HISTORIES. 145 



term the vernal, in contrast to the aestival series, 

 hibernate as half -grown caterpillars and produce 

 the earliest brood of butterflies ; these make their 

 appearance 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 before July 

 or the end of June that is, about the time 

 when the butterflies of the aestival series ap- 

 pear ; the eggs hatch speedily and the cater- 

 pillars grow as usual, moulting twice ; beyond 

 this point all the caterpillars do not develop 

 alike ; some continue in what would appear the 

 most natural way ; as caterpillars they eat, as 

 chrysalids they sleep, and then appear in Sep- 

 tember, gay and frolicsome butterflies but 

 doomed, I believe, to an untimely end ; for the 

 cold autumnal blasts sweep them away before the 

 eggs are fully developed in their ovaries. It is, 

 however, possible that some of them may lay eggs 

 which, hatching, produce larvae which at once 

 hibernate and the following year become members 

 of the aestival series.* It appears more probable, 



* Since this was written, some facts have come under my own 

 and others' observation, leading to the belief, as suggested in the 

 text as possible, that the butterflies of this brood lay eggs at 

 once, and that the caterpillars from them hibernate in their 

 earliest stage, thus transferring their allegiance the following 



