Type species: aenigma Prout, Taiwan.
Though the facies is atypical of the Boarmiini, the presence of a
cucullus on the valve and the general structure of the male genitalia, indicate
this genus belongs within the boarmiine complex. The pupal cremaster in the two
Japanese species (material sent to the author by Dr. R. Sato) is robust, rather
asymmetric, bearing at least four major spines. This may indicate that the
concept of the Boarmiini presented here is paraphyletic, with at least Acrodontis
branching off more basally from most of the Boarmiini than do the three
other tribes with a bifid cremaster.
The insect is large with an irregularly falcate forewing apex. The
pattern consists of irregular mottling and blotching of rufous, pink and grey on
a pale yellow ground; darker post medial fasciae are present, more or less
punctate, and a broad, diffuse, discal spot on the forewing. The pattern is
repeated on the underside.
The male antennae are bipectinate almost to the apex, those of the
female filiform. In the abdomen, the tympanic bullae are relatively small. A
fovea is present on the male forewing.
In the male genitalia the gnathus is robust, the tongue-like apical
portion coarsely scobinate. The cucullus of the valve is well developed, the
zone with coarse, short setae extending well basal along the costal margin and
having a central lobe in the type species and the Japanese A. fumosa Prout.
The sacculus terminates distally in a quadrate process, and a band of
sclerotisation extends from it towards the costa. The aedeagus vesica bears
scobination, often coarse, but no major cornuti; the apex of the aedeagus
extends as sclerotised bands that bear spines, one or several.
The female genitalia have an extensively sclerotised lamella postvaginalis, with a system of fine folds surrounding a central zone that is
less scobinate than the rest. The ductus is short, the base of the tubular
section of the bursa scobinate and irregularly folded transversely. In the
pyriform distal portion there is a transverse, mouth-shaped signum, a
modification of the usual ‘mushroom’ type.
Larvae of the two Japanese species were illustrated by Sugi (1987). They
are robust, finely striped longitudinally with white and blue-black, with
irregular red or yellow patches along the flanks in association with the legs,
prolegs and spiracles. One species is polyphagous but A. fumosa is
restricted to Stachyurus (Stachyuraceae). This monobasic plant family
extends from the Himalayas to Japan but is not known from Borneo or eastwards.
The genus is restricted to China, Japan and Korea apart from the new
species described below.
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