ORTHOPTBRA. 287 



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 in color in this 

 Order. The male of an American cricket*' is described as being as 

 white as ivory, whilst 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 Phasmidse) "is of a shin- 

 "Ing 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, Neiwoptera. — Little need here be said, except as to color. 

 In the Ephemeridse the sexes often differ slightly in their ob- 

 scure tints;'" but it is not probable that the males are thus ren- 

 dered attractive to the females. The Libellulidse, or dragon-flies, 

 are ornamented with splendid green, blue, yellow, and vermilion 

 metallic tints; and the sexes often differ. Thus, as Prof. West- 

 wood remarks,™ the males of some of the Agrionidse, "are of a 

 'rich blue with black wings, whilst the females are fine green with 

 "colorless wings." But in Agrion Ramburii these colors are ex- 

 actly reversed in the two sexes." In the extensive N. American 

 genus of Hetserina, the males alone have a beautiful carmine spot 

 at the base of each wing. In Anax Junius the basal part of the 

 abdomen in the male is a vivid ultramarine blue and in the fe- 

 male grass-green. In the allied genus Gomphus, on the other 

 hand, and in some other genera, the sexes differ but little in 

 color. In closely-allied forms throughout the animal king- 

 dom, similar cases of the sexes differing greatly, or very 

 little, or not at all, are of frequent occurrence. Although there is 

 so wide a difference in color between the sexes of many Libel- 

 lulidse, it is often diflBcult to say which is the more brilliant; and 

 the ordinary coloration of the two sexes is reversed, as we have 

 just seen, in one species of Agrion. It is not probable that their 



« Mr. Ch. Horn©, in 'Proc. Bnt. Soc' May 3, 1869, p. xii. 



" The Oecanthus nivalis. Harris, 'Insects of New England,' 1842, 

 p. 124. The two sexes of Oe. pellucidus of Europe differ, as I hear 

 from Victor Carus, in nearly the same manner. 



*« Platyhlemnus : Westwood, 'Modern Class.' vol. i. p. 447. 



*» B. D. Walsh, the 'Pseudo-neuroptera of Illinois,' in 'Proc. Ent. 

 Soc. of Philadelphia,' 1862, p. 361. 



s" 'Modern Class." vol. ii. p. 37. 



" Walsh, ibid. p. 381. I am indehted to this naturalist for the fol- 

 lowing facts on Hetaerina, Anax, and Gomphus. 



