S80 THE DESCENT OF MAN 



sexes rarely differ much in color, it is not probable that 

 they owe their bright tints to sexual selection. Conspicuous 

 colors may be of use to these insects, by giving notice that 

 they are unpalatable. Thus it has been observed" that a 

 bright-colored Indian locust was invariably rejected when 

 offered to birds and lizards. Some cases, however, are 

 known of sexual differences of color in this Order. The 

 male of an American cricket" is described as being as white 

 as ivory, while the female varies from almost white to 

 greenish-yellow or dusky. Mr. Walsh informs me that the 

 adult male of Spectrum femoratum (one of the Phasmidae) 

 "is of a shining brownish-yellow color; the adult female 

 being of a dull, opaque, cinereous brown; the young of both 

 sexes being green. ' ' Lastly, I may mention that the male 

 of one curious kind of cricket" is furnished with "a long 

 membranous appendage, which falls over the face like a 

 veil"; but what its use may be is not known. 



Order, Neuroptera. — Little need here be said, except as 

 to color. In the Ephemeridae the sexes often differ slightly 

 in their obscure tints ;" but it is not probable that the males 

 are thus rendered attractive to the females. The Libellu- 

 lidse, or dragon-flies, are ornamented with splendid green, 

 blue, yellow, and vermilion metallic tints; and the sexes 

 often differ. Thus, as Prof. Westwood remarks,'" the males 

 of some of the Agrionidse "are of a rich blue with black 

 wings, while the females are fine green with colorless 

 wings." But in Agrion Ramburii these colors are exactly 

 reversed in the two sexes." In the extensive North Ameri- 

 cans genus of Hetserina, the males alone have a beautiful 



*« Mr. Oh. Home, in "Proc. Ent. Soc," May 3, 1869, p. xii. 



■*' The (Ecanfhus nivalis. Harris, "Insects of New England," 1842, p. 124. 

 The two sexes of CE. peUucidus of Europe differ, as 1 hear from Victor Oarus, 

 in nearly the same manner. 



^ Piatyblemnus : "Westwood, "Modern Clas.," vol. i. p. 447. 



■" B. D. Walsh, the "Pseudo-neuroptera of Illinois," in "Proc. Bnt. Soc, 

 of PhUadelphia," 1862, p. 362. 



™ "Modern Class.," vol. ii. p. 3?. 



" Walsh, ibid., p. 382. I am indebted to this naturalist for the following 

 facts on Hetasrina, Anaz, and Gomphus. 



