The male cochineal has a long body with very delicate wings, transparent and which at a distance look like those of a bee; he is provided with a sort of tail formed of two silky strands. One sees him flying over the nopals, then suddenly alighting on a female, who resembles a fat wood-louse round and puffy, twice as stout as the male, wingless. Glued by her feet to a branch, with her proboscis stuck into it, continually pumping sap, she looks like a fruit, like an oak-apple or oak-gall on a peduncle for which reason Réaumur called her picturesquely the gall-insect. In certain species of cocides the male is so small that his proportion is that of an ant strolling over a peach. His goings and comings are like those of an ant hunting for a soft spot to bite, but he is seeking the genital cleft, and having found it, often after long and anxious explorations, he fulfills his functions, falls off and dies.
[1] These are neuroptera or pseudo-neuroptera, but their habits bring them noticeably near to social hymenoptera.
[2] Souvenirs entomologiques, tome V. p. 256.
_II. Vertebrates:--Unnoticeable in fish, saurians, reptiles.--The Bird World.--Dimorphism favourable to males: the oriole, pheasants, the ruff.--Peacocks and turkey-cocks.--Birds of paradise.--Moderate dimorphism of mammifers.--Effects of castration on dimorphism._
II. Vertebrates.--Sexual differences are generally unnoticeable in fish, reptiles and saurians. They are accentuated when we come to superior vertebrates, to birds and mammals, but without ever attaining the extreme difference which characterizes a great number of arthropodes. In birds the disparity may be of colouring, size, or length, form and curliness of the feathers; among mammals, of shape, hair, beard or horns. Sometimes the female bird is finer and stronger; thus stronger and of more powerful wing-spread in the case of the secretary, the buzzard, the falcon, the ash-coloured vulture and many birds of prey; more beautiful as in the Indian tumices.[1] One of them, the gray phalarope, solves woman's dream in favour of the female, leaving her the brilliant colours; the male contents himself with more sober clothing and, not being able to lay, assumes at least the further maternal cares: sitting on the eggs.