ON THE VARIATION OP INSECTS. 37 



Howard, in describing this Clialcid from New Mexico, mentions 

 that four females had a black shade in the middle of the 

 mesocutum, and black instead of yellow axillae, thus resembling 

 the normal S' of the species. — Following the line of argument 

 under " h," these will appear as examples of reversion to the 

 primitive type, which has been maintained typically in one sex, 

 but lost in the other. From the facts recorded by Mr. J. Bland 

 Sutton, concerning a female golden-pheasant which took the 

 plumage of the male, and his comments thereon, it would appear 

 probable that the immediate cause of this reversion to the 

 supposed primitive type is the abortion of the organs of 

 generation. In many species of vertebrata the young of one sex 

 resemble closely the adult of the other in superficial characters ; 

 it may be that some Lepidoptera pass through a primitive stage, 

 which characterises the adult of the opposite sex, in the pupa, 

 and the sexual organs being occasionally aborted at this critical 

 moment, the secondary sexual characters do not further develop, 

 resulting in a specimen such as those referred to above. It 

 would, therefore, be of the highest interest if any future captor 

 of such a specimen would dissect it while fresh, and examine the 

 condition of the reproductive organs. 



k. Seasonal forms. 



Papilio ajax, spring form telamonides, Feld., and summer form 

 marcellus, Bd. Pieris protocUce, spring form vernalis, Edw., is 

 smaller and darker than the summer form. P. oleracea, summer 

 form often larger, and wings thinner and purer white than spring 

 form. P. rapcB, " Farther south (in the United States) the winter 

 (spring) form tends to pure white on the upper surface " (G. H. 

 French). Colias eurytlieme, spring form keeivai/din, Edw., smaller 

 than summer form, duller yellow and with less roseate reflection, 

 both sides more sprinkled with black scales, the orange patch on 

 the fore wings not so marked, sometimes almost absent. Phyciodes 

 tharos, seasonal forms marcia, Edw., and morpheus, Fb. ; P. p)haon 

 also has seasonal forms. Grapta interrogationis, hybernating form 

 fabricii, Edw., summer form umbrosa, Lintn. ; " There are about 

 four broods in a season, and while those of the last or hybernating 

 brood are the pale forms, the others are more or less mixed, as 

 Mr. Edwards has shown" (G. H. French). G. comma, hyber- 

 nating form harrisii, Edw., summer form dryas, Edw. Lyccena 

 pseudargiolus vars. lucia, Kirby, and marginata, Edw., coming from 

 pupfe which have hybernated, show coalescence of markings on 

 the under side of the hind wings. Selenia hilunarla jidlaria, 

 Haw., and S. lunaria deliinaria, Hb. — In North America, owing 

 to the great difference between the summer and winter climates, 

 seasonal forms are often very marked. As a rule, the spring 

 form, emerging from pupse which have hybernated, is smaller 



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