Mythimna (Pseudaletia) separata Walker

Leucania separata Walker, 1865, List Specimens lepid. Insects Colln. Br. Mus., 32: 626.

Leucania consimilis Moore, 1881, Proc. zool. Soc. Lond., 1881: 336.

Pseudaletia separata Walker; Franclemont, 1951 : 65; Calora, 1966 : 701;Holloway 1976 : 9.

Diagnosis

The forewing is pinkish buff, with a straight brownish streak running from the apex obliquely to the postmedial row of dots. Vein CuA in the cell is delineated darkly, with the dark broadening at the discal end. Compared with the next species, the cucullus is narrow, asymmetric, and the sacculus is also much narrower.

Geographical range

Indo-Australian tropics and subtropics to Fiji, Samoa, E. Australia, Norfolk I. and New Zealand; migratory in subtropics.

Habitat preference

The species is rare and perhaps restricted to montane localities in Borneo. Two specimens were taken at 2600m on G. Kinabalu and a third at 2360m near the summit of G. Mulu.

Biology

bell (MS) has described the larva in India as typically trifine in form, light mauve-brown in colour, marbled orange-brown, with lateral and subspiracular, yellowish, longitudinal bands each edged white and containing the orange-brown marbling. There is a narrow white dorsal line. The ventrum is pale green. Sugi (1987) illustrated a somewhat greener larva than indicated by Bell’s description but with similar features. The eggs are laid on young parts of the plant, and the larva attacks tender shoots. Pupation is on the ground in an oval chamber lined thinly with silk to which the cremaster points are attached.

Host plants in the Gramineae are Andropogon, Brachiaria, Dactylis,Echinochloa, Oryza, Panicum, Saccharum, Setaria, Triticum, Zea, and it is a serious pest of many graminaceous crops (Robinson, 1975; Miyata, 1983; Bell, MS; CIE Records). Miyata (1983) also mentions Ipomoea (Convolvulaceae), Gossypium (Malvaceae), Fagopyrum (Polygonaceae), Raphanus and Brassica (Cruciferae).

Genitalia: