By some authorities the double-brooded _bistortata_ is {313} considered specifically distinct from the, normally, single-brooded _crepuscularia_; others hold the opposite view. The March and April moths are generally rather browner in colour than those appearing in May and June, but I have some specimens taken in Wiltshire at the end of March, which are quite as pale as any example in the May-June series. Probably, we should be right in regarding _crepuscularia_ as the older stock from which the double-brooded race, _bistortata_, has sprung. The former has a more extensive range, as it inhabits Northern Europe (Sutherlandshire in British Isles), whilst _bistortata_ seems to be confined to Central Europe. A Perthshire form of the May-June race is shown on Plate 136, Fig. 7; and an example of ab. _delamerensis_, White, from Delamere Forest, Cheshire, is represented by Fig. 8. Figs. 6 [male], 7 [female], represent examples of the March and April race. Black or blackish forms, with the sub-marginal line more or less distinctly white, occur in both races, chiefly in Glamorganshire, South Wales. {314} A photograph, by Mr. H. Main, of the caterpillar, is reproduced on Plate 138, Fig. 3. The general colour is grey, inclining to yellowish or brownish; sometimes it is reddish brown; two broken dark-grey lines on the back, and some pale blotches on the sides. The caterpillars of the first race (_bistortata_) feed in May and June, and again in August and September. Those of the second race in June and July, or later. They seem to eat the foliage of trees, including those in orchards. NOTE.--Cross-pairings between _bistortata_ [male] and _crepuscularia_ [female] resulted in the ab. _ridingi_, Tutt, whilst the offspring of a crossing of _crepuscularia_ [male] and _bistortata_ [female] have been named _bacoti_, Tutt. Pairings of _bistortata_ [male] and _delamerensis_ [female] produce ab. _ridingi-suffusa_, Tutt; and those of _delamerensis_ [male] and _bistortata_ [female] = _bacoti-suffusa_, Tutt. Further, _bacoti-suffusa_ will pair with _ridingi-suffusa_, or the last named with _crepuscularia_; the progeny being in the first case _mixta_, Tutt, and in the latter, _reversa_, Tutt. BRINDLED WHITE-SPOT (_Tephrosia luridata_). Two examples of this species (also known as _extersaria_, Hubner) are depicted on Plate 137, Figs. 1 [male], 2 [female]. There is variation in the amount of black speckling and in the strength of the cross lines.