ZOOLOGY. 281 



ings of the American Academy of Arts and Sciences, Boston, 

 the author states that Darwin, in his work on sexual selec- 

 tion, discusses the difference of coloration which frequently 

 distinguishes the sexes of butterflies, and concludes that " the 

 male, as a general rule, is the most beautiful, and departs 

 most from the usual type of coloring of the group to which 

 the species belongs." Mr. Scudder remarks that of the first 

 proposition there is no doubt, but that in the second two dis- 

 tinct elements appear to be confounded, the separation of 

 which he attempts. He suggests the term antigeny, signify- 

 ing opposition or diversity of the sexes, to avoid circumlocu- 

 tion, for there are so many forms of sexual dimorphism that 

 a compound term for the general phenomenon becomes in- 

 convenient. He cites a number of cases of partial antigeny, 

 and concludes that in all these cases it is the female, and 

 never the male, which first departs from the normal type of 

 coloring of the group to which the species belongs. Occa- 

 sionally the feminine peculiarity has been transmitted to the 

 male, and by this means a new type of coloration established 

 in the group ; but Mr. Scudder recalls no case where the 

 male alone departs from the general type of coloring pecul- 

 iar to the group. This is precisely the opposite conclusion 

 to that which Darwin reached. 



Sexual dimorphism is not confined to coloration, but to 

 structural features. The latter is alwavs confined to the 



ml 



males, and in butterflies is mostly confined to the wings and 

 the legs ; occasionally it appears in the antenna}, while some- 

 times it affects the contour of the wings. 



Darwin supposes that the various male characteristics 

 have all arisen by natural selection, one of rival males be- 

 ing selected as a mate whose outward charms are greatest. 

 Mr. Scudder brings forward as limiting this notion the fact 

 that the males of many butterflies possess peculiar cells, 

 which he calls androconia, and are of great beauty and deli- 

 cacy, but are hidden among the others. In this respect the 

 theory of sexual selection proposed by Darwin appears to 

 fail just where it should aid us most. 



Anatomy and Physiology. 



In an account of experiments on the sense organs of in- 

 sects in the American Naturalist, Mr. A. S. Packard, Jr., 



