EUPLOEINAE: ANOSIA PLEXIPPUS. 743 



hai)s, aware that the valley of this river is one in which southern butter- 

 flies find their way ftirther north than at any other point in New England, 

 exce))ting in some instances along the seaboard. 



My own collecting in New p:ngland, where this butterfly is nuich less 

 common than further south, leads me to believe that it is far easier to ob- 

 tain it by search for the caterpillar on the leaves of Asclepias, than by 

 capture upon the wing ; and I would rather decide upon the presence of 

 butterflies in any particular district by a search for plants of Asclepias in 

 suito,ble spots than by watching for the butterflies ; so that the failure year 

 after year to find such larvae on young and tender plants in the very spots 

 whicli are invariably chosen by the July butterfly whereon to deposit its 

 eggs, is to me very strong proof that the buttei-fly does not ordinarily exist 

 in any form during the early months of the year in regions that I have 

 searched. Regarding the later broods it may be added that the observa- 

 tions of Mr. Marsh, who raised butterflies as late as the latter half of Octo- 

 ber and even in November, were made, in part at least, upon housed 

 larvae, and that at this late epoch of the year the transformations of the 

 insect are very much slower than they are earlier in the season. Thus 

 Mr. Marsh himself states that the pupal period in October is about three 

 weeks, while in September it is only about a fortnight. In midsummer it 

 is about ten to twelve days. 



Mr. Edwards, accepting a suggestion of Mr. Marsh, further urges that 

 the failure to discover the hibernators in the spring is due to their rarity in 

 the autumn, and the latter from the fact that in New England the fields 

 are often mowed for a second crop, and that with the hay great quantities 

 of milk weed are cut down. But aside from the fact that the larger part 

 of the milk Aveeds inhabited by the caterpillars are found by the side of 

 roads and lanes and in close vicinity to shrubbery, where it is not disturbed 

 by the scythe, there is a single fact which renders this argument absolutely 

 useless, viz., that the imago is usually far more abundant late in the season 

 than at any other time in the year, sometimes swarming to an excessive 

 extent, and found in New England in the same abundance that it is so 

 often found in the west. Yet so far as I have been able to find from in- 

 quiries (unfortunately not made at the time) in no instance have hiber- 

 nators been seen in years immediately succeeding autumns which have 

 witnessed a vast profusion of butterflies, nor have autumns of great abund- 

 ance been followed by springs of plenty. 



In the extreme south the butterflies do not hibernate, but continue on 

 the wing throughout the winter. :Mr. Thaxter often observed them pair- 

 ing in the winter in Florida (Can. ent., xii : 38) while they were in flocks 

 (which he recently writes me were first observed by him January 3, 187fi), 

 and although, as before stated, Dr. Chapman finds them rare in Florida 

 from May to November, Gosse in Alabama reports a larva in June, and 



