When full grown, in the autumn, the caterpillar is velvety black, and above this colour is most in evidence between the rings; the back is clothed with dense, short, bright reddish brown or tawny hair, and the whole body is covered with brownish hairs, varying in length, but always much longer than the tawny ones; along each side are some whitish hairs. Head blackish covered with brownish hairs. It feeds in August and onwards to October, when it seeks winter quarters, reappearing in the following spring, but not feeding again. After enjoying the sunshine whenever the opportunity offers through the early months of the year, it finally pupates in March or April. The cocoon is a long, more or less tubular, brownish construction of silk and larval hairs. It is spun up, usually somewhat upright, low down among the food plant, or at the roots of grass, etc.; sometimes among moss, when the rounded head end can just be seen above the moss (Plate 58). In certain localities and seasons the caterpillars have been seen in enormous numbers, but such profusion only happens now and then. In some districts they may be abundant one year, and then scarce or quite absent for several years. When handling the larvæ it will often be noted that the tips of one's fingers are thickly felted with the tawny hairs from the creature's back; if these hairs get transferred to the face or neck considerable irritation may be the result. [Illustration] Pl. 58. FOX MOTH: _caterpillars_. [Illustration] Pl. 59. 1, 2. FOX MOTH, _males_; 3 _female_. {123} The late Mr. Robson used to collect the caterpillars on fine days in early spring, put each caterpillar into a separate paper box about two inches square, and keep them on a shelf over the kitchen fire, where they would duly pupate. Various methods for keeping these caterpillars through the winter have been described, and all appear to have been fairly successful. The most simple would seem to be the following: Bore a number of holes in the bottom of a roomy box, and fasten wire gauze on a close fitting frame to serve as a top. Cut a tuft or two of heather to cover the floor space of the box. Caterpillars collected in the autumn may be put into this receptacle and supplied with food, such as bramble or sallow, as long as they seem inclined to feed. Do not crowd too many into the box, and let it stand out in the garden, preferably on the soil. The moths emerge in May or June. The males are very active on the wing in the afternoon sunshine, and later on, and may often be seen in numbers dashing hither and thither in an apparently erratic flight over heaths and open spaces, in search of the females. The latter do not fly till night, and occasionally they are attracted to a bright light. Except that it has not been noted in the Shetlands, the species occurs throughout the British Isles. Abroad its range extends over Europe, and it is found in Amurland. THE DRINKER (_Cosmotriche potatoria_).