338 SEXUAL SELECTION. [Part h. 



Order, Thysanura. — The members of this Order are 

 lowly organized for their class. They are wingless, dull- 

 colored, minute insects, with ugly, almost misshapen heads 

 and bodies. The sexes do not differ ; but they offer one 

 interesting fact, by showing that the males pay sedulous 

 court to their females even low down in the animal scale. 

 Sir J. Lubbock, 17 in describing the Smynthurus luteus, 

 says : " It is very amusing to see these little creatures co- 

 quetting together. The male, which is much smaller than 

 the female, runs round her, and they butt one another, 

 standing face to face, and moving backward and forward 

 like two playful lambs. Then the female pretends to run 

 away and the male runs after her with a queer appearance 

 of anger, gets in front and stands facing her again ; then 

 she turns coyly round, but he, quicker and more active, 

 scuttles round too, and seems to whip her with his antenna) ; 

 then for a bit they stand face to face, play with their an- 

 tenna?, and seem to be all in all to one another." 



Order, Diptera (Flies). — The sexes differ little in color. 

 The greatest difference, known to Mr. F. Walker, is in the 

 genus Bibio, in which the males are blackish or quite 

 black, and the females obscure brownish orange. The 

 genus Elaphomyia, discovered by Mr. Wallace 18 in New 

 Guinea, is highly remarkable, as the males are furnished 

 with horns, of which the females are quite destitute. The 

 horns spring from beneath the eyes, and curiously resemble 

 those of stags, being either branched or palmated. They 

 equal in length the whole of the body in one of the spe- 

 cies. They might be thought to serve for fighting, but, as 

 in one species they are of a beautiful pink-color, edged 

 with black, with a pale central stripe, and as these insects 

 have altogether a very elegant appearance, it is perhaps 



17 ' Transact. Linnean Soc' vol. xxvi. 1868, p. 296. 

 ' The Malay Archipelago,' vol. ii. 1869, p. 313. 



