Achrosis lithosiaria Walker comb. n.

Omiza lithosiaria Walker, 1862, List Specimens lepid. Insects Colln Br. Mus. 24 :1085.

Diagnosis

This and Achrosis rigorata Prout have similar uniform grey forewings, but the angled forewing margin in lithosiaria has been lost in rigorata; the latter has straight oblique fasciae, but these are irregular and only strong costally and sometimes dorsally in lithosiaria. The female forewings are more rufous in lithosiaria.

Taxonomic Notes

The species is close in facies to the Himalayan A. quadraria Warren comb. rev. It resembles Achrosis rigorata Prout also, sharing the uniform, grey forewings and spinose aedeagus apex.

The larva of Achrosis lithosiaria has been reared from an unidentified shrub in Peninsular Malaysia (S.K.L. Hok & H.S. Barlow, pers. comm.) and is illustrated in Plate 9. The ground colour is a dull, pale emerald green throughout, except for T1 which is more yellowish. All parts are marked in black as illustrated, the head with four dorsal patches with a pair of lateral bars ventral to these. The thoracic and abdominal segments have transverse bars of black, the latter each having three, the most anterior one broken, the second almost entire, and the most posterior one entire, and much broader on A1-4. The black markings are in broader patches over the ventral part of the body. Though the host plant is unidentified, the genus appears to be closely associated with Ixora (Rubiaceae) as discussed in Part 11.