Mecistoptera group of genera
This group, which should probably also include Hepatica Staudinger and Gonoglasa Hampson, treated already by Holloway (2005), shows some cohesion in general build, facies and genital characters, but falls apart if the position of the counter-tympanal hood is applied rigorously to separate the Hypeninae from the Herminiinae as recommended by Lödl (1997). This convention has, however, been breached by Owada (1998) in his placement of the genus Ochrotrigona Hampson (see p. 86) in the Herminiinae. Whilst Mecistoptera has the herminiine condition of a prespiracular counter-tympanal hood, the other genera have the postspiracular, hypenine condition. However, Lödl at a later date (1999d: 150), in his revision of Perciana Walker, drew attention to the similarities of that genus (e.g. the valve structure) to Mecistoptera, and suggested that both genera were hypenine, also casting doubt on whether the hood character is fully reliable for separating the two groups.
There are several features that are seen in most or all of the genera suspected to belong to the complex. The forewings are obtusely angled at the centre of the margin and are slightly bifalcate in some members of the group (e.g. Mecistoptera, Perciana). The hindwings have a straight (sinuous in Perciana), dark fascia that runs from the tornus forward to meet the costa at approximately two-thirds. The abdomen extends well beyond the hindwings by perhaps a third or more of its length. The phragma lobes between the first two abdominal tergites are very large as in the Hypena group, triangular. The labial palps are usually slender, directed forwards to twice the length of the head; the third segment is shorter and narrower than the second. The male antennae are fasciculate or ciliate, though some species of Acidon Hampson have them serrate. See also preliminary comments on this group published by Holloway (2005: 29, 402, 416).
The male abdomen is of the framed corematous type, with the frame of the sternite approximately square, though the anterior part of the frame is concave, with the weak coremata close to it. When coremata are more developed, they are paired, rather than single as in Herminiinae. The tergite is reduced, in extreme cases to a trifid sclerite consisting of the splayed apodemes and a posterior extension of sclerotisation from their meeting point. The genitalia have a rounded angle to the ventral inner margin of the tegumen on each side. The juxta in several genera is longer than broad, somewhat ovate or flask-shaped, with a central structure that often consists of two long, dorsally converging pleats (e.g. Fig 393). The valves are rather narrow, tongue-like, expanding to a rounded apex, with a longitudinal pleat or groove running up the centre from the base of the costa. This pleat is associated on its costal side with strong, often complex, always slender processes in Hepatica, Mecistoptera and Perciana, but all taxa have a digitate process near the very base of the saccular zone. This can be directed towards the costa or towards the apex of the valve.
In the female genitalia, the ostium is often wide, associated with the posterior of the eighth segment, and the ductus is short. The corpus bursae is ovate to elongate, with the ductus seminalis arising basally from it on one side from a slight appendix directed posteriorly. This appendix, the bursa and the ductus are frequently extensively but finely scobinate, often with slight corrugation. The scobination may be concentrated into a slight signum in the distal part of the bursa.
The larvae of Mecistoptera (see below) have the prolegs on A4 reduced and those on A3 minute.
The genera that are clearly members of the group on the basis of these features are predominantly Oriental, though Acidon has one species in Madagascar and Mecistoptera extends to New Guinea. The male genitalia illustrated (Wiltshire, 1979) for the Indian Metoponrhis fuscipars Hampson, stated by Wiltshire to be atypical for the genus Metoponrhis Staudinger, show some features of the group, and are particuarly similar to those of some Acidon species. Of more dubiously associated genera, Gonoglasa is also Oriental. Radara Walker has some similarities of build, including an abdomen distinctly longer than the hindwings, and a similar forewing shape to the group, but has somewhat different abdominal features and should probably be excluded; it is a pantropical genus.
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