On Plate 107 will be found figures of the early stages. The egg, which is usually laid on the upper side of a terminal leaf of bird's-foot trefoil (_Lotus corniculatus_) or on rest-harrow (_Ononis spinosa_), is whitish-green in colour, netted with glossy white. The caterpillar is green, covered with short brownish hairs, with which are mixed some longer ones; it is wrinkled on the side, ridged on the back, and the line along the middle of the back is darker. Head black and glossy. The chrysalis is green, with the head, wing-cases, and sometimes the hinder parts of the body, tinged with buff; thorax brighter green, rather shiny; a darker line down the centre of the body. The plants mentioned, and especially rest-harrow, are known to be the food of the caterpillar, but eggs have also been found, in Scotland, on red clover, plantain, burnet saxifrage, and yarrow. The caterpillars are to be found, after hibernation, in April, and a second brood in June and July. Those feeding on rest-harrow seem to prefer the blossom. This caterpillar is stated to form a cocoon, but the only approach to any such structure made by the seven individuals I had under observation was in the case of two caterpillars that pupated among leaves of _Lotus_, which were drawn together by the slenderest of threads. Four effected the change at the bottom of the cage and seemed to be quite free, one had climbed to the leno top of the cage and there spun a silken carpet under itself, which drew the leno together, and so formed a shallow cave in which the chrysalis rested. In every case the cast skin was attached to the tail, and so remained after the butterflies emerged. The butterfly is to be found almost everywhere in the country, and its distribution extends throughout the United Kingdom, except, perhaps, the Shetland Isles. There appears to be only one flight in the north of Scotland and Ireland, and this occurs in June and July. In England there are two broods, and in some years probably three in the southern counties. It may be seen on the wing, in greater or lesser numbers, all through the season from May to September. Abroad, the range extends over the whole of Europe to North Africa, and through Western and Northern Asia to Amurland and China.