616 THE BUTTERFLIES OF NEW EXGLAXl). 



Avhich have been })r()duced directly without any interruption and those 

 which came from the retarded caterpillars, seem to behave in a different 

 way, the first feeding until they have passed two or three moults (or the 

 lethargic period in this caterpillar) , when they go into hibernation for the 

 winter ; while the caterpillars from the later eggs, laid by butterflies pre- 

 sumably from the retarded caterpillars, hibernate at once after leaving the 

 eiT"" : and this difference in age of the hibernating caterpillars no doubt 

 accounts, at least in part, for the length of time during which in the 

 spring fresh butterflies make their appearance. 



It is a curious fact that in all the experiments of ISIr. Edwards in the 

 Catskills and in West Virginia, upon the allied species B. myrina, he has 

 in no case observed any instance of lethargy on the part of caterpil- 

 lars obtained by him. But as it has been observed in this species in the 

 neiohborhood of Boston, in caterpillars raised from the eggs obtained from 

 Professor Hamlin about AVaterville, ISIe., as well as in those from eggs 

 obtained about Boston in several instances and in different years, there 

 can be no doubt that such a phenomenon does sometimes occur, at least in 

 the present species. In both the spring brood and the mid-summer brood 

 of butterflies, there are many instances, as I have found by repeated 

 examination covering many different years, in which the eggs are not 

 developed in the body of the mother until the butterfly has to all appear- 

 ance been upon the Aving for several weeks, and even apparently for more 

 than a month ; and it would appear from the condition of those in which 

 eo-o-s were found (though of this there can be of course no absolute i>roof), 

 that when the eggs are not developed at birth they do not develop in the 

 body of the female until at or about the time of the api)earance of the 

 subsequent brood of butterflies, so that one finds upon the wing and lay- 

 ino- eo-o-s at the same time individuals of the first and second and of the 

 second and third broods. My failure years ago to obtain eggs from fresh 

 females in July and September, led me to believe that all the eggs laid at 

 that time were laid by old decrepit females, and the hypothesis of two 

 series of individuals was constructed partly on this basis. It has since 

 been proven by my own observations, as well as by those of others, that the 

 fresh individuals of the two later broods often lay eggs shortly after eclo- 

 sion. But I have not yet been able so to obtain them from individuals of 

 the first brood. It thus appears probable that a mixture of broods takes 

 place in two distinct ways : first, by the conniiingling of fresh and worn 

 eo-jT-laying females upon the wing late in July and late in August, i. e., 

 belonging to the first and second, and the second and third broods, and 

 second by lethargy on the part of the caterpillars of one brood by which 

 the l)utterflies produced from them apparently form a part of the brood 

 which regularly succeeds them in time. It should be remarked also that, 

 as observed by seAcral of my correspondents, this butterfly is very much 



