many insects, the legs are furnished with peculiar spines, knobs or
spurs; or the whole leg is bowed or thickened, but this is by no means
invariably a sexual character; or one pair, or all three pairs are
elongated, sometimes to an extravagant length. (8. Kirby and Spence,
Introduct. etc., vol. iii. pp. 332-336.)
[Fig. 10. Taphroderes distortus (much enlarged). Upper figure, male;
lower figure, female.]
The sexes of many species in all the orders present differences, of
which the meaning is not understood. One curious case is that of a
beetle (Fig. 10), the male of which has left mandible much enlarged; so
that the mouth is greatly distorted. In another Carabidous beetle,
Eurygnathus (9. Insecta Maderensia, 1854, page 20.), we have the
case, unique as far as known to Mr. Wollaston, of the head of the
female being much broader and larger, though in a variable degree, than
that of the male. Any number of such cases could be given. They abound
in the Lepidoptera: one of the most extraordinary is that certain male
butterflies have their fore-legs more or less atrophied, with the
tibiae and tarsi reduced to mere rudimentary knobs. The wings, also, in
the two sexes often differ in neuration (10. E. Doubleday, Annals and
Mag. of Nat. Hist. vol. i. 1848, p. 379. I may add that the wings in
certain Hymenoptera (see Shuckard, Fossorial Hymenoptera, 1837, pp.
39-43) differ in neuration according to sex.), and sometimes
considerably in outline, as in the Aricoris epitus, which was shewn to
me in the British Museum by Mr. A. Butler. The males of certain South
American butterflies have tufts of hair on the margins of the wings,
and horny excrescences on the discs of the posterior pair. (11. H.W.
Bates, in Journal of Proc. Linn. Soc. vol. vi. 1862, p. 74. Mr.
Wonfor s observations are quoted in Popular Science Review, 1868, p.
343.) In several British butterflies, as shewn by Mr. Wonfor, the males
alone are in parts clothed with peculiar scales.
The use of the bright light of the female glow-worm has been subject to
much discussion. The male is feebly luminous, as are the larvae and
even the eggs. It has been supposed by some authors that the light
serves to frighten away enemies, and by others to guide the male to the
female. At last, Mr. Belt (12. The Naturalist in Nicaragua, 1874, pp.
316-320. On the phosphorescence of the eggs, see Annals and Magazine
of Natural History, Nov. 1871, p. 372.) appears to have solved the
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