This very pretty little insect is the blue butterfly one sees everywhere, abounding in meadows, on heaths and downs, and not at all confined to chalky soils, like some other "blues." The _caterpillar_ is green, with darker stripe on the back, and white spots on each side. It feeds on Bird's-foot Trefoil and other leguminous plants. The _butterfly_ is to be found almost constantly from the end of May to the end of September, being double-brooded. * * * * * THE SILVER-STUDDED BLUE. (_Polyommatus Ægon._) (Plate XIV. fig. 5, male; 5 _a_, Female.) _Colouring_:--Upper side, _male, purplish blue_ (rather deeper than that of Alexis), with a rather broad black margin. Female, dark brown, sometimes slightly tinged with blue, and bordered on the hind wings with dull orange spots; but these are often absent. Fringe white, _not_ barred with black. Under side, _near the margin of the hind wings_, and between that and the orange border spots, are several _metallic spots, of a bluish tint_, whence the insect has its name of "Silver-studded." {159} The _caterpillar_ is brown, with white lines. Feeds on broom and other plants of the same order. The _butterfly_ appears in July and August, and is very frequently met with throughout the country on heaths, commons, and downs, both on sandy and chalky soils. In many places it is the commonest of the "Blues." It has been found at Epping; Coombe Wood; Darenth Wood; Box Hill; Ripley, Surrey; Brighton; Lewes; Deal; Lyndhurst; Blandford; Brandon, Suffolk; Holt, Norfolk; Birkenhead; Bristol; Sarum, Wiltshire; Lyme Regis; Parley Heath, Dorsetshire; Manchester; York; several places in Scotland. * * * * * THE BROWN ARGUS. (_Polyommatus Agestis._) (Plate XIV. fig. 6.) Though this butterfly and the next are classed among the "Blues," from their possessing the same structure and habits, there is _no trace of blue_ in the colouring of _either sex_, as in all the preceding species of _Polyommatus_.