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Show 360 SEXUAL SELECTION. .PART II. same object gained by the most diversified means; this being due to the whole organisation undergoing in the course of ages multifarious changes; and as part after part varies, different variations are taken advantage of for the same general purpose. Tho diversificatio~. of the means for producing sound in the three fam1hes of the Orthoptora and in the Homoptera, impresses the mind with the high importance of these structures to the males, for the sake of calling or alluring the female~. vV e need feel no surprise at the amount of modification which the Orthoptera have undergone in this respect, as we now know, from Dr. Scudder's remarkable discovery,42 that there has been more than ample time. This naturalist bas lately found a fossil insect in the Devonian formation of New Brunswirk, which is furnished with "the well-known tympanum or stridulating apparatus "of the male Locustidre." This insect, though in most respects related to the N europtera, appears to connect, as is so often the case with very ancient forms, the two Orders of the Neuroptera and Orthoptera which are now generally ranked as quite distinct. I have but little more to say on the Orthoptera. Some of the species are very pugnacious: when two male field-crickets (Gryllus campest1·t"s) are confined together, they fight till one kills the other ; and the species of Mantis are described as manamvring with their sword-like front-limbs, like hussars with their sabres. The Chinese keep these insects in little bamboo cages and match them like game-cocksY \!Vith respect to colour, some exotic locusts are beautifully ornamented ; the posterior wings being marked with red, 42 'Transact. Ent. Soc.' 3rd series, vol. ii. ('Journal of Proceedings, p.ll7.) 43 Westwood, 'Modern Class. of Insects,' vol. i. p. 427; for crickets, p. 445. C!lAl' . X. NEUROPTERA. 361 1lue, and black; but as throughout the Order the two sexes rarely differ much in colour, it is doubtful whether they owe these bright tints to sexual selection. Conspicuous colours rna y be of use to these insects as a protection, on the principle to be explained in the next chapter, by giving notice to their enemies that they are unpalatable. Thus it has been observed 44 that an Indian brightly-coloured locust was invariably rejected when offered to birds and lizards. Some cases, however, of sexual differences in colour in this Order are known. The male of an American cricket45 is described as being as white as ivory, whilst the female varies from almost white to greenish-yellow or dusky. l\fr. vValsh informs me that the adult male of Spectrum femoratum (one of the Phasmidro) "is of a shining "brownish-yellow colour; the adult female being of " a dulJ, opaque, cinereous-brown; the young of both " sexes being green.'' Lastly, I may mention that the male of one curious kind of cricket 46 is furnished with "a long membranous appendage, which falls over the -''face like a veil;'' but whether this serves as an ornament is not known. Order, Newtoptera.-Little neeu here be said, except in regard to colour. In the Ephemer.idro the sexes often differ slightly in their obscure tints ;47 but it is not probable that the males are thus rendered attractive to the females. The Libellulidre or dragon-flies .are ornamented with splendid green, blue, yellow, and ~4 ~Ir. Ch. Horne, in' Proc. Ent. Soc.' 1\fa.y 3, 18GD, p. xii. 4 5 The Oecanthus nivalis. Harris, 'Imects of :New En.,.land ' 1 8!2 p. 124. 0 ' ' ~ 6 Platyblemnus: ·westwood,' Modern. Class.' vol. i. p. 447. 4 7 B. D. Walsh, the Psendo-neuroptera oflllinois, in' Proc. Ent. Soc. <>f Philudelphin,' 1862, p. 3Gl. |