Risoba obstructa Moore

Risoba obstructa Moore, 1881, Proc. zool. Soc. Lond., 1881: 328.

Risoba grisea Bethune-Baker, 1906, Novit. zool., 13: 234, **syn. n.

**

Diagnosis

This species is a smaller, greyer version of the prominens/olivens pair in the vialis group. The forewing apical brown patch is narrower, with the section of the submarginal adjacent to it more oblique. The postmedial meets the dorsum obliquely, with an acute angle distad and a slight kink. In olivens this line curves round distad to meet the dorsum with an acute angle basad; prominens is somewhat intermediate as discussed below. See the generic introduction for distinctive features of the male genitalia which are very different from those of members of the vialis group.

Taxonomic note

The male genitalia of obstructa and grisea appear identical, with features described in the generic introduction and illustrated.

Geographical range

Sri Lanka, India, Thailand, Borneo, Java, Philippines, Sulawesi, New Guinea, Queensland, Solomons (Bougainville).

Habitat preference

The three specimens seen are from Brumas and Tampanuli in Sabah, both lowland localities.

Biology

Bell (MS) and Gardner (1941, 1948a) recorded the larva in India, and Moore (1883) illustrated it from Sri Lanka. It has a transverse hump on A8. The body in Sri Lanka is purplish brown with dorsal and lateral broken white lines and a sublateral row of whitish streaks. The banding in S.India (Bell) is yellowish white to orange. Bell described the behaviour; it is similar to that of basalis.

Host plants recorded by these authors and others (Robinson et al., 2001) are species of Quisqualis, Terminalia (Combretaceae), Xylia (Leguminosae), Lagerstroemia (Lythraceae) and Sterculia (Sterculiaceae).

Genitalia: