The species is widely distributed over the southern and eastern counties, common in many parts; but its range extends through England to Durham, and it has been recorded from Wales. Although it does not seem to have been noted in Scotland south of Kincardineshire, it occurs on the east to Moray. Westmeath is the only Irish locality that has so far been mentioned. Its distribution abroad extends to East Siberia and Amurland. THE LIGHT ORANGE UNDERWING (_Brephos notha_). Very similar to the last species, but rather smaller in size, and the fore wings are much less variegated. The antennae of the male of this species are bipectinated, whilst those of _parthenias_ are finely serrated. (Plate 38, Figs. 4 [male] and 5 [female].) [Illustration] 2 Pl. 38. 1, 2. ORANGE UNDERWING. 3. THE REST HARROW. 4, 5. LIGHT ORANGE UNDERWING. 6-8. GRASS EMERALD. [Illustration] 2 Pl. 39. 1. ORANGE UNDERWING: _caterpillar_. 2, 2a. LIGHT ORANGE UNDERWING: _caterpillar and chrysalis_. 3. LESSER BELLE: _caterpillar_. {99} The caterpillar feeds in May and June on aspen, eating the foliage and hiding between two leaves drawn together. The head is greenish or greenish-brown, with three conspicuous black spots. Body, green, olive-green, or reddish; line along middle of the back darker green edged with white; two thin white lines on each side, and a whitish stripe along the spiracles. When mature it burrows into decayed bark or wood (virgin cork in confinement), and before changing to a reddish-brown chrysalis, it spins a thin covering of silk and woody particles over the mouth of the chamber. The caterpillar and the chrysalis are shown on Plate 39, Figs. 2 and 2a. Although the bulk of the moths emerge the following April, some have been known to remain until the following or even the third year. The males fly about aspen, but only in the sunshine; in other respects its habits are pretty much those of the last species. The distribution of the species in England seems confined to two areas: a western one represented by Worcester, Gloucester, with Monmouth, Wales, Wilts, and Dorset; and an eastern one by Norfolk, Cambridgeshire, Suffolk, Essex, Middlesex, Kent, Surrey, and Sussex. In Scotland only recorded from Moray. The range abroad extends to Amurland. GEOMETRIDAE.