crickets, p. 445.) With respect to colour, some exotic locusts are
beautifully ornamented; the posterior wings being marked with red,
blue, and black; but as throughout the Order the sexes rarely differ
much in colour, it is not probable that they owe their bright tints to
sexual selection. Conspicuous colours may be of use to these insects,
by giving notice that they are unpalatable. Thus it has been observed
(46. Mr. Ch. Horne, in Proceedings of the Entomological Society, May
3, 1869, p. xii.) that a bright-coloured Indian locust was invariably
rejected when offered to birds and lizards. Some cases, however, are
known of sexual differences in colour in this Order. The male of an
American cricket (47. 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.) 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 Phasmidae) is of a
shining brownish-yellow colour; 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 (48.
Platyblemnus: Westwood, Modern Classification, vol. i. p. 447.) 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 colour. In the Ephemeridae the
sexes often differ slightly in their obscure tints (49. B.D. Walsh, the
Pseudo-neuroptera of Illinois, in Proceedings of the Entomological
Society of Philadelphia, 1862, p. 361.); but it is not probable that
the males are thus rendered attractive to the females. The
Libellulidae, or dragon-flies, are ornamented with splendid green,
blue, yellow, and vermilion metallic tints; and the sexes often differ.
Thus, as Prof. Westwood remarks (50. Modern Classification, vol. ii.
p. 37.), the males of some of the Agrionidae, are of a rich blue with
black wings, whilst the females are fine green with colourless wings.
But in Agrion Ramburii these colours are exactly reversed in the two
sexes. (51. Walsh, ibid. p. 381. I am indebted to this naturalist for
the following facts on Hetaerina, Anax, and Gomphus.) In the extensive
N. American genus of Hetaerina, the males alone have a beautiful
carmine spot at the base of each wing. In Anax junius the basal part of
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