Chap. VIII.] SEXUAL SELECTION. 305 



as 122.7 to 100 females. But the numbers are hardly large 

 enough to be trustworthy. 



On the whole, from the above various sources of evidence, 

 all pointing to the same direction, I infer that, with most species 

 of Lepidoptera, the males in the imago state generally exceed the 

 females in number, whatever the proportions may be at their first 

 emergence from the egg. 



With reference to the other Orders of insects, I have been 

 able to collect very little reliable information. "With the stag- 

 beetle {Lucanus cermis) " the males appear to be much more 

 numerous than the females ; " but when, as Cornelius remarked 

 during 1867, an unusual number of these beetles appeared in one 

 part of Germany, the females appeared to exceed the males as 

 six to one. With one of the Elateridte, the males are said to be 

 much more numerous than the females, and " two or three are 

 often found united with one female; " '* so that here polyandry 

 seems to prevail. With Siagonium (Staphylinidie), in which the 

 males are furnished with horns, " the females are far more 

 numerous than the opposite sex." Mr. Janson stated at the 

 Entomological Society that the females of the bark-feeding 

 Tomicus villosus are so common as to be a plague, while the 

 males are so rare as to be hardly known. In other Orders, from 

 unknown causes, but apparently in some instances owing to 

 parthenogenesis, the ujales of certain species have never been 

 discovered, or are excessively rare, as with several of the Cyni- 

 pidffi." In all the gall-making Cynipidaj known to Mr. Walsh, 

 the females are four or five times as numerous as the males ; and 

 so it is, as he informs me, with the gall-making Cecidomyiife 

 (Diptera). With some common species of Saw-flies (Tenthre- 

 dinaj) Mr. F. Smith has reared hundreds of specimens from larvai 

 of all sizes, but has never reared a single male : on the other 

 hand, Curtis says,"^ that with certain species (Athalia), bred by 



«* Giinther's 'Record of Zoological Literature,' 1867, p. 260. On the 

 excess of female Lucanus, ibid. p. 250. On the males of Lucanus in Eng- 

 land, Westwood, 'Modern Class, of Insects,' vol. i. p. 187. On the Sia- 

 gonium, ibid, p 172. 



" Walsh, in 'The American Entomologist,' vol. i. 1869, p. 103. F 

 Smith, ' Record of Zoological Literature,' 1867, p. 328. 



'^ 'Farm Insects,' pp. 45, 46. 

 14 



