The Descent of Man

times 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 neu-