for in the true Libellulae, when the sexes differ in colour, the
females are orange or yellow; so that supposing Agrion to be descended
from some primordial form which resembled the typical Libellulae in its
sexual characters, it would not be surprising that a tendency to vary
in this manner should occur in the females alone.
Although many dragon-flies are large, powerful, and fierce insects, the
males have not been observed by Mr. MacLachlan to fight together,
excepting, as he believes, in some of the smaller species of Agrion. In
another group in this Order, namely, the Termites or white ants, both
sexes at the time of swarming may be seen running about, the male
after the female, sometimes two chasing one female, and contending with
great eagerness who shall win the prize. (54. Kirby and Spence,
Introduction to Entomology, vol. ii. 1818, p. 35.) The Atropos
pulsatorius is said to make a noise with its jaws, which is answered by
other individuals. (55. Houzeau, Les Facultes Mentales, etc. Tom. i.
p. 104.)
ORDER, HYMENOPTERA.
That inimitable observer, M. Fabre (56. See an interesting article,
The Writings of Fabre, in Nat. Hist. Review, April 1862, p. 122.),
in describing the habits of Cerceris, a wasp-like insect, remarks that
fights frequently ensue between the males for the possession of some
particular female, who sits an apparently unconcerned beholder of the
struggle for supremacy, and when the victory is decided, quietly flies
away in company with the conqueror. Westwood (57. Journal of
Proceedings of Entomological Society, Sept. 7, 1863, p. 169.) says
that the males of one of the saw-flies (Tenthredinae) have been found
fighting together, with their mandibles locked. As M. Fabre speaks of
the males of Cerceris striving to obtain a particular female, it may be
well to bear in mind that insects belonging to this Order have the
power of recognising each other after long intervals of time, and are
deeply attached. For instance, Pierre Huber, whose accuracy no one
doubts, separated some ants, and when, after an interval of four
months, they met others which had formerly belonged to the same
community, they recognised and caressed one another with their
antennae. Had they been strangers they would have fought together.
Again, when two communities engage in a battle, the ants on the same
side sometimes attack each other in the general confusion, but they
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