Miscellaneous Genera VI
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Chorsia Walker Gen. rev.

Type species: maculosa Walker.

Synonyms:
Aeologramma Strand (type species picatum Butler, Borneo) syn. n.; Neustrotia Sugi (type species japonica Warren, Japan) syn. n.; Poecilogramma Butler (praeocc.; type species picatum) syn. n.; Pseuderiopus Warren (type species albiscripta Hampson; Indian Subregion, Japan, Borneo) syn. n.

Aeologramma was treated previously in this series (Holloway, 1989) in the subfamily Amphipyrinae, but shares the features of facies and the male and female abdomen used here to define Chorsia and distinguish it from Oglasa. It included three Bornean species that must now be transferred to Chorsia: C. picatum Butler comb. n. (endemic); C. decolorata Holloway comb. n. (endemic) and C. albiscripta Hampson comb. n. (widespread Oriental; see above).

The species assigned to
Neustrotia Sugi in Inoue et al. (1982) have facies and male genitalia characters as in Chorsia, and Neustrotia is therefore brought into synonymy. The genus was originally placed in the Acontiinae by Sugi (loc. cit.), though he placed the probably related Microxyla Sugi (see p. 413 and note under C. perversa Walker comb. n. below) in the Ophiderinae. Ueda (1984, 1987) investigated Neustrotia in relation to other Japanese Acontiinae and found it to have several characters that distinguished it from the other genera studied, including the fused sacculi of the male genitalia noted below. He inferred it occupied a ‘peculiar position’ in the subfamily. The higher classification of this whole generic complex needs resolution and will be revisited when the remaining Noctuidae parts of this series are in preparation.

The male antennae are fasciculate and the third segment of the labial palps is a third or less the length of the second, and very small to the point of invisibility in the group with the modified uncus mentioned later. The hindwing has vein M2 present but weak and well separated from M3, whereas in
Oglasa it is more closely associated. One species included here, C. rufitincta Hampson comb. n., was in fact originally also described in an amphipyrine genus as discussed below.

The forewings are narrower but the facies is normally very similar to that seen in typical
Oglasa, with two darker brown triangles on the costa and a darker brown area at the anterior half of the distal margin. However, there is often a brown patch centrally or on the dorsum also, and the reniform is punctate rather than obliquely lunulate. On the underside there is almost always a subapical white or paler spot within the uniform dark ground, a feature shared with typical Pseudogyrtona. Something similar is seen in Hypena Schrank and allies.

The male abdomen has a framed pair of coremata, usually basal, on the sternite, the frame anteriorly rounded and often bilobed posteriorly. The coremata of the type species are unusually large and dark, and there is a small central apodeme on the seventh sternite. In
Oglasa the frame is broader, the sides converging slightly towards the posterior. The eighth tergite of Chorsia has a narrow central sclerotisation that expands at the distal margin, whereas the reverse holds in Oglasa or the thickening occurs both anteriorly or posteriorly. The genitalia are similar to those of Oglasa except the valves have the saccular bases broadly adjacent to fused in the centre of the diaphragma rather than well separated as in Oglasa. In one group, the uncus has a prominent dorsal process. The aedeagus vesica varies in breadth and in the number and complexity of the diverticula.

In the female genitalia (
C. hemicyclopis Hampson comb. n., C. albiscripta, C. greenleavesi sp. n.), the corpus bursae is generally distinctly scobinate without this scobination being intensified in a signum as in Oglasa. The ductus seminalis arises on a tapering, reflexed diverticulum at the base of the corpus bursae, a feature also seen to some extent in Oglasa. The ductus is lightly sclerotised over most of its length, and the ostium can be set just distal to a slight notch or excavation in the posterior margin of the seventh sternite, whereas the latter is straight in Oglasa.

The genus may prove to be diverse in the Oriental tropics and warm temperate latitudes, as it is in Borneo, and certainly requires further study. Two non-Bornean species that should be transferred are
C. trigona Hampson comb. n. (S. India) and C. trichocera Hampson comb. n. (Philippines). Chey (1994) noted members of the genus as frequent in softwood plantations in the lowlands of Sabah.

Sugi (1987) observed that larvae of Japanese species were associated with deciduous trees, and cited the observation of Nozaki (1987) that the final instar of one species does not feed and soon enters the soil to pupate; its head capsule is smaller than that of the preceding instar. He noted that Gardner (1947) had described a similar phenomenon in
C. trigona Hampson (as Metachrostis trigona), including significant differences in the structure of the mandibles of final and penultimate instars, that of the latter being normal with an entire distal margin and a strong, curved, subapical carina on the inner face, and that of the former being reduced, with one long and two shorter acute distal teeth. Both instars are green, the final one immaculate, the penultimate one with many of the setae arising from black spots. The prolegs of A3 are absent, those of A4-6 nearly equal. Gardner stated that the final instar did not feed, and formed its cocoon between leaves almost immediately. The host plant of C. trigona was Dalbergia (Leguminosae).

Bell MS) described the larva of C. albiscripta, but this was not included for the species by Holloway (1989). It is cylindrical, with the prolegs on A3 absent but those on A4 only very slightly reduced. The head is broader than deep, grass-green, tinged yellow and spotted with groups of light sepia dots; the setae arise from black dots. The body is smooth, the segments clearly defined; the primary setae are set on small chalazae, colourless except for those on A1, A2 and all supraspiracular ones. The colour is grass-green, with a thin, whitish spiracular line, and variably with a darker green or maroon dorsal band. Bell did not refer to any differences between the last two instars. The larva lives fully stretched on the underside of host plant leaflets or the midrib of the leaf. It pupates on the ground in a roomy silken cell containing earth particles, the larva turning pink before pupation. The host plants were in the genus Dalbergia (Leguminosae) with the moth showing a preference for climbing species. Robinson et al. (2001) additionally recorded Amphicarpaea from the same family.

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