The _butterfly_ is chequered on the upper surface with {140} tawny, and dark brown or black. It appears in May and June, and again in August, being found in woods, principally in the south, and its range is often confined to a small spot hardly fifty yards in diameter, within which it may be quite plentiful. The following are among its recorded localities:--Carlisle; Lake District; West Yorkshire; Roche Abbey, Yorkshire; Peterborough; Stowmarket; Pembury; Barnwell Wold, Northants; Oxford; Blandford; Worcester; Gloucestershire; Bedfordshire; Epping; Coombe Wood; Darenth Wood; Boxhill; Dorking; Brighton; Lewes; Worthing; Lyndhurst; Teignmouth. The _males_ of all the members of the family to which this butterfly belongs, and of which this is the sole European representative--_the_ ERYCINIDÆ--have only _four_ legs adapted for walking, whilst the _females_ have _six_. * * * * * THE BROWN HAIR-STREAK. (_Thecla Betulæ._) (Plate XII. fig. 1, Male; 1 _a_, Female.) The genus to which this butterfly belongs, contains five British species, elegant and interesting insects, though not gaily tinted. They are most obviously distinguished from other small butterflies by the _tail-like_ projection on the lower edge of their hind wings (though one of their {141} number, _T. Rubi_, has this very slightly developed). From each other they are best distinguished by the characters on their under surface, where they all bear a more or less distinct _hair_-like _streak_, whence their common name--Hair-streak. The Brown Hair-streak is the largest of the genus, measuring sometimes an inch and two-thirds in expanse. The two sexes differ considerably on the upper surface, the male being of a deep brown colour, slightly paler near the middle of the front wing, while the female possesses on the front wing a _large patch of clear orange_. Both sexes have several orange marks upon the lower angles of the hind wings. Beneath, the general colour is tawny orange with duller bands, and marked with one white line on the front wing, and _two parallel white lines on the hind wings_. The _caterpillar_ is green, marked obliquely with white; it feeds on the birch and also on the sloe. The _butterfly_ appears in August, continuing into September. It is generally distributed through the south, but is by no means an abundant insect. Mr. Stainton observes that it has a habit of "flitting along in hedges just in advance of the collector;" but it is also found in oak woods in company with the Purple Hair-streak.