Both sexes are blackish, or sooty-brown; the male is powdered, more or less, with silvery-blue scales. The under side is greyish-white with a tinge of blue at the base of each wing, but chiefly on the hind pair; the spots are black encircled with white. As will be seen on turning to the plate, there is variation in size. Fig. 5 represents a giant race occurring in some localities, and the particular specimen depicted was taken, with many others, on the coast near Lymington, Hants; it seems to be referable to var. _alsoides_, Gerhard. Variation on the under side is usually in the direction of complete absence of spots, but Mr. Joy has recorded a specimen with the spots on the hind wings extended into streaks of considerable but varying length. Figures of the early stages will be found on Plate 114. The egg is pale greenish in colour, netted with whitish; it is laid in June on the calyx of a flower-bud, generally low down, of the kidney-vetch (_Anthyllis vulneraria_). According to Buckler, caterpillars hatched on June 21 from eggs laid between the 16th and 18th of that month, and at once commenced to feed on the flowers of the kidney-vetch, and made their way to the seed, for which they evinced a marked preference. When full grown, the caterpillar is brownish, sometimes tinged with pink. The fine bristles are dark brown; there is a darker line along the middle of the back, and a line of dark marks on each side. The head is black and shining. The chrysalis is described by Buckler as "dirty whitish-grey, approaching to drab, palest on the back of the abdomen, greyish on the head and thorax, both of which are marked with a black dorsal stripe, which is a little interrupted; on either side is a subdorsal row of short slanting black dashes. The pale ground colour is sprinkled with some very minute black specks. The head, thorax, and abdomen are hairy with bristly whitish hairs." Although the caterpillars feed up rather quickly and are full grown and apparently ready to assume the chrysalis state, they do not effect the change until the following May or June. [Illustration: _Pl._ 114. =Small Blue.= _Eggs, natural size and enlarged; caterpillar and chrysalids._] [Illustration: _Pl._ 115. =Small Blue.= 1 _male_; 2, 3 _female_; 4, 5, 6, 7, 8 _male vars_. =Mazarine Blue.= 9, 11 _male_; 10, 12 _female_.] The butterfly emerges in about three weeks, so it will be seen that this species continues the caterpillar existence for something over ten months.