“Eublemma” brachygonia Hampson

Eublemma brachygonia Hampson, 1910, Cat. Lepid. Phalaenae Br. Mus., 10: 166.

Diagnosis

This species, as well as abrupta Walker, members of the versicolor Walker subgroup and perversicolor sp. n., have very similar markings of the Autoba type, consisting, on the forewing, of an oblique medial that runs from the dorsum to a subcostal angle; the postmedial is more irregular and crenate but also has a subcostal angle distal to that of the medial such that these fasciae meet the costa much further apart than where they almost coincide at the angle of the medial. The oblique course of the medial can be continued through this point of contact by a subsidiary line almost to the apex (absent in brachygonia). There is a straight central fascia on the hindwing that also continues this line in a similar form. The three species are all approximately the same size but show diagnostic variants on this theme. The ground in brachygonia and abrupta Hampson is a darker brown than in the versicolor group which is more fawn to straw colour or violet-grey, and slightly darker and richer in abrupta than brachygonia. The forewing medial in brachygonia is pale, with a narrow rufous edging basally; the angle is rather blunt, and the postmedial is obscure and does not come as close to the angle of the medial as in the other two. In abrupta the medial is doubled, with a greyish tinge to the paler band between the two components; there is a small pale lens enclosed between the postmedial beyond its angle and the subsidiary line that continues the oblique fascia, placing this lens subapically at the costa; there is also a diagnostic dark spot at the tornus of the hindwing. In versicolor the forewing medial is single, often conspicuously darker, the dark grading away distad (particularly well developed in the holotype (OUMNH)) and continuing evenly as a subsidiary line to the apex. The ground colour in the versicolor subgroup, as indicated by its name and earlier above, is basically fawn to violet-grey, but can be suffused strongly with pinkish brown, and this suffusion often intensifies at the distal margins of the wings.

Taxonomic note

This species has not been reliably identified from Borneo, though the larva has been recorded as feeding on various fruit trees in Thailand (Kuroko & Lewvanich, 1993). Voucher material reared in Peninsular Malaysia from mango in BMNH proved to belong to an externally very similar species that also occurs in Sulawesi and might therefore in future be recorded from Borneo. There is a third species in New Guinea, the Bismarck Is. and Queensland to which the name lurida Pagenstecher stat. rev. is applicable (shown below). Poole (1989) placed lurida as a synonym of abrupta, but the facies is more as in brachygonia. However, the male genitalia of lurida (Fig 320) have, on the valve, a longer, more tongue-like central setose process than in brachygonia, where this is acutely triangular and accompanied by a slight bulge on the ventral margin of the valve, so the former should be treated as a distinct species. E. latericolor Turner (Queensland) has similar male genitalia to lurida, and is probably conspecific. The species from Peninsular Malaysia and Sulawesi (shown below) is undescribed and has a darker discal spot on the forewing than in typical brachygonia (the specimen illustrated by Kuroko & Lewvanich is of this type, so its identity is uncertain). A male from Sulawesi (Fig 319; slide 21229) has the valve membranous in a similar position to the bulge of brachygonia and the saccular process is smaller, rounded, and more obliquely based. The female genitalia (Fig 323) are similar to those of lurida (Fig 324) with a pyriform corpus bursae that, at its widest, is twice as wide as the narrow, sausage-like corpus of brachygonia; no pair of spines is present in this trio or in abrupta, a feature that distinguishes the species from those of the versicolor subgroup and the four species that follow it. Reference to this trio of species is therefore included here to facilitate distinction from other very similar species that do occur in Borneo, particularly the six immediately following. The species were all placed in Autoba by Poole (1989).

Geographical range

Indian Subregion, ?Thailand (Kuroko & Lewvanich, 1993; see above).

Habitat preference

Chey (1994) recorded brachygonia from softwood plantations near Brumas in the lowlands of Sabah, but this represents a misidentification of E. castanea Hampson (see p. 186).

Biology

According to Bell (MS), the larva of brachygonia is more cylindrical than spindle-shaped, with only a slight narrowing at each end. Prolegs are absent from A3 and A4. The head is glossy, the body smooth, with the setae on small cylindrical chalazae. The colour is light olive-green, tinged brown, marbled paler subcutaneously in a way that may form a dorsal band (sometimes pure white) and more obscure lateral lines.

The larva lies on the branches of the flower panicles of the host under a light silken web into which are woven flower particles. It rests fully stretched or with the front of the body curled. It feeds on the flower panicles and pupates in a more compact cell of the same type.

Robinson et al. (2001) recorded the larva as feeding on the flowers and fruit of the following:

• Buchanania, Mangifera (Anacardiaceae)
• Indigofera, Senna (Leguminosae)
• Dimocarpus, Lepisanthes, Litchi, Nephelium (Sapindaceae).

Genitalia:

Other images: