Anachrostis Hampson

Type species: nigripuncta Hampson, Sri Lanka.

This, Neachrostia and Trigonochrostia belong to a complex that is much in need of revision but, as in the superficially similar Micronoctuidae, this needs to be done on the basis of a much more substantial body of material. Indeed, many of the species involved may prove to be Micronoctuidae and are under study by M. Fibiger as indicated below.

The typical facies in Anachrostis is much as in the Bornean species described below and has a general resemblance to some lithosiines in Eugoa Walker and to the Micronoctuidae. The forewing venation has the radial sector veins reduced to four, the anterior and posterior ones arising independently from the cell, and the central two being stalked. The hindwing venation is also reduced, with M2 lost; Rs and M1, and M3 and CuA1 are stalked. The phragma lobes between the first and second abdominal tergites are vestigial.

In the male abdomen, the eighth tergite is enlarged, somewhat ovate, with a central ridge of thickening. The sternite is short, with the sides and anterior margin forming a narrow, incomplete frame. The seventh tergite has an inverted T-shaped thickening at the anterior margin, but the sternite is very much enlarged to more than twice the length of a normal segment, with spines, asymmetrically sized, arising from each posterior corner. The anterior margin is rather rounded and overlaps the semicircular sixth sternite, and the fifth also has a curved anterior margin. The genitalia show striking bilateral asymmetry, mainly in the long, slender valves that have subbasal and central processes, the latter also slender, arising from the costa. The tegumen is very much longer than the vinculum and can be rather straight. The uncus is also straight, narrow, and slightly tapering to a blunt apex. The genitalia of three Japanese species are illustrated by Sugi in Inoue et al. (1982) and show these features clearly, but the uncus in all three is shorter than in the type species.

In the female, the ductus is narrow, tubular and somewhat sclerotised, with a flexure at two-thirds from the ostium, which opens at the anterior of the eighth segment. The corpus bursae is pyriform but with a very long neck that is swollen and thickened, at the distal end and with the ductus seminalis arising just distal to the junction with the ductus bursae. There is a pyriform sclerite with four widely separated transverse ridges situated at the base of the distal sphere of the corpus bursae.

Poole (1989) listed eight further Oriental species, three from New Guinea and eastwards and one African one in the genus. However, some of these, particularly the more easterly ones, may prove to be Micronoctuidae, such as elachista Fletcher from the Rennell Is. which has male genitalia that show several micronoctuid features such as loss of the uncus and a strongly developed juxta and anellar structure. Fletcher (1957) indicated that the male genitalia of A. minima Hampson (Sumbawa) and A. timorensis Hampson were similar. These are being studied by M. Fibiger.