Netria viridescens Walker

Netria viridescens Walker, 1855, List lepid. Insects in Colln Br. Mus. 6: 1504; Kiriakoff, 1968: 138; Holloway 1976: 56, Fig. 361.

Diagnosis

This large species is unmistakable in its green forewings with darker, finely fasciated medial and basal bands. There is some variation in the green tone (usually paler in the larger female) and the intensity of the banding.

Taxonomic Note

Schintlmeister (1994b, 2006) discovered that the large, apparently widespread species Netria viridescens Walker was in fact a major complex of ten species, with three species flying in Borneo. They are all very similar in facies, and best distinguished from features of the male eighth segment and genitalia. One is true viridescens, which has a single, asymmetrically placed spine on the eighth tergite and a rounded apex to the corresponding tergite. The uncus has two robust digitate processes, the valves are relatively gently curved over the narrow apical part, the juxta is broad, and the saccus moderate in length. This is the species of which the genitalia were illustrated by Holloway (1976: fig 361). The typical race flies in Sundaland, with ssp. pallidabasis Schintlmeister in Palawan and ssp. continentalis Schintlmeister and ssp. suffusca Schintlmeister in mainland Asia, the last, in Yunnan and Burma, disrupting the continuity of the range of continentalis.

Geographical range

Oriental tropics to New Guinea.

Habitat preference

On G. Kinabalu the species was taken infrequently on the transect sampled to as high as 2600 m. In the Mulu survey it was infrequent in lower and upper montane forest but more common in kerangas and lowland limestone forest. It was common at 300 m in hill dipterocarp forest at Ulu Temburong, Brunei.

Biology

The life history has been studied in the Indian Subregion (Moore 1882-4, Lepid. Ceylon Vol II; Bell MS).

The egg, 2.7 mm by 1.4 mm, is a low dome with a closely pitted surface, pale yellowish white.

The larva is a stout, rather elongate ovoid shape, narrower posteriorly than anteriorly, bifid anally. The head is large, oval, shiny-granular, with short hairs. The body is smooth, dull, green in colour with an orange-red ‘collar’; a broadish dorsal ‘pulsating’ plum-coloured line runs the length of the body from the collar, edged by equally broad whitish lines; there is a ventrolateral white to yellow band below the spiracles. A series of yellow diagonal lines occurs on each side, and the whole surface is invested with small yellow dots, each bearing a hair. The tips of the anal points are pink. The white spiracles are ringed outwards with black, blue-green and brown.

The larvae live on the undersides of the leaves of their host-plant, feeding only on young leaves. Recorded host-plants are all in the family Sapotaceae: Bassia, Mimusops, Sideroxylon (Bell MS); Achras sapota (CIE records, India).