532 THE BUTTERFLIES OF NEW ENGLAND. 



and the distinction is so slight it might be readily overlooked, yet it is 

 the only difference one can find, and there is nothing analogous to it in 

 the allied species, V. cardni. On the other hand, the two sexes of Erora 

 laeta have so different an appearance that it is not strange that they were 

 originally described by the same person as two distinct species ; and the 

 difference is still more marked in the Chrysophanidi, where it may possibly 

 be said to affect also the pattern of coloration. In one species, Epidemia 

 epixanthe, the female, besides lacking on its upper surface the brilliant and 

 peculiar lustre of the opposite sex, is also marked by the presence of a 

 row of blackish spots, which is quite wanting in the male. In another, 

 Chrysophanus tlioe, the male has the upper surface of a deep coppery hue, 

 with a narrow black border ; while the female has a deep orange color 

 with a broad black margin and a transverse row of distinct black spots 

 near the middle of the outer half of the wing, which appear in the male 

 only through the diaphanous nature of the wings, the same row occurring 

 in both sexes upon the under surface. This strikes us as the more remark- 

 able, since in the two New England genera which are most closely allied to 

 it, and with one of which it is usually directly associated, no such sexual 

 distinction is found. A somewhat similar example occurs in Papilio 

 polyxenes, the male of which presents upon the upper and under surfaces of 

 all the wings, a little distance beyond the middle, a transverse series of yel- 

 lowish or orange spots, which are equally distinct on the under surface of the 

 female, but partially or sometimes wholly obsolete above. In Thymelicus 

 brettus we have even a more conspicuous example. The female is very 

 dark brown, almost black, with two little yellow spots in the middle of 

 the front wings ; while the male differs totally, being tawny, with indented 

 brown borders and an oblique black dash in the middle of the front wings : 

 at first glance no one could suppose them identical. In Semnopsyche 

 (liana the male is a rich dark brown, with a very broad fulvous margin 

 upon all the wings, marked on the front wings by one or two rows of 

 black spots. The female, on the other hand, is a rich purple black, with 

 no trace of fulvous, but with the space where it belongs occupied on the 

 fore wings by three rows of white spots and dashes, and on the hind wings 

 by two belts of blue, broken into spots, one of the belts narrows the other 

 exceedingly broad.* 



It is not a little remarkable that in all these examples, and indeed in 

 very nearly all that have come under my notice, this sexual diversity is 

 displayed only upon the upper surface of the wings, and almost invariably 

 upon the fore wings, f a mark of ancestry and of the lower position of 



* Here, however, as will be shown in an- large patch of glistening scales on the under 



other excursus, the difterence is really due to surface of the fore wings (Butt. India, ii : 8) ; 



another disturbing element, mimicry. and what under the circumstances is curious, 



t De Nic6ville states that in Ergolis, a genus these butterflies always settle with expanded 



of oriental Nymphalidae, the males have a wings. 



