Very similar to the last species, but rather smaller in size, and the fore wings are much less variegated. The antennæ of the male of this species are bipectinated, whilst those of parthenias are finely serrated. (Plate [38], Figs. 4 ♂ and 5 ♀.)
|
| 2 Pl. 38. |
| 1, 2. | Orange Underwing. | 3. | The Rest Harrow. |
|
| 4, 5. | Light Orange Underwing. | 6-8. | Grass Emerald. |
|
|
| 2 Pl. 39. |
| 1. | Orange Underwing: caterpillar. |
|
| 2, 2a. | Light Orange Underwing: caterpillar and chrysalis. |
|
| 3. | Lesser Belle: caterpillar. |
|
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.
GEOMETRIDÆ.