During the hottest summer months, and particularly in August and September, a rather small brown moth may be seen almost everywhere, flying rapidly and in a very erratic manner in the bright rays of the midday sun. This is the common Vapourer Moth, which may be known at once by its bright chestnut colour, with darker transverse markings, and a white crescent-shaped spot in the anal angle of the fore wings. It seems somewhat partial to civilised life, for it frequents the streets of our metropolis, even in the very densely populated parts; and the larva is one of the commonest of the insect forms infesting our gardens and squares. [Illustration: FIG. 125.--THE VAPOURER MOTH--MALE.] [Illustration: FIG. 126.--THE FEMALE VAPOURER.] The caterpillar is variously coloured; but the prevailing tints are dark brown, grey, and pink. On the second segment are two long tufts of hair directed forward, and on the twelfth segment a similar tuft directed backward. On each of the segments five to eight inclusive is a brush-like tuft of yellowish hairs. It feeds on almost every tree usually to be found in parks and gardens. When fully grown it spins a web on the bark of a tree, or on a wall or fence, and changes to a hairy chrysalis. [Illustration: FIG. 127.--LARVA OF THE VAPOURER MOTH.] The female of this species is wingless, and never moves away from the cocoon out of which she has crawled, but lays her eggs on the outside of the silken web, and there remains to die. The clusters of eggs may be found in abundance throughout the winter months. Family--BOMBYCIDAE This family contains eleven thick-bodied moths, mostly of large size, in which the predominating colours are greys and browns. Their hind wings are generally paler than the front pair, and less distinctly marked; and the antennae of the males are pectinated. The caterpillars are very hairy, but the hairs are uniformly distributed, and not arranged in tufts as in the larvae of the last family. The chrysalides are inclosed in silken cocoons, but are not hairy. We shall briefly examine three of the members of this family. _The Oak Eggar_ (_Bombyx Quercus_) The male of this species is shown on Plate X (fig. 5). The female is much larger, and of a pale tawny colour. The ground colour of the caterpillar is black; but it is so closely covered with short yellowish brown hairs that the black is scarcely visible, excepting when the creature rolls itself up into a ring, which it does when alarmed. The spiracles are white, and there is a series of white spots down the middle of the back and along each side. It feeds on whitethorn (_Crataegus oxyacantha_), heather (_Calluna_, _Erica_), poplar (_Populus nigra_), and various other plants and trees.