Acygnatha Hampson

Type species: atrapex Hampson.

This genus bears some resemblance in facies to the aventiine genus Cerynea, particularly omphisalis, the type species, but the upcurved labial palps with a long, very slender third segment are atypical of the subfamily. Nye (1975) and Poole (1989) assigned the genus to the Ophiderinae, and it is added to the miscellaneous sequence here.

The male abdomen (atrapex) is of the framed corematous type, the sternite with slender lateral rods to a similarly slender frame that supports a finely scobinate (possibly setal bases) membrane that fills it. There were no phragma lobes evident between the first two abdominal tergites. The genitalia have a slender, downcurved uncus. The valves are relatively short, robust, tapering and unequally bifid at the very apex. The juxta is approximately square, with the dorsal side concave. The aedeagus vesica lacks cornuti.

The female genitalia show features that could indicate placement in the Aventiinae: vestigial apodemes on the eighth segment that are associated with slightly scobinate pockets on each side of the obliquely ovate ostium; a slight coil to the neck of the corpus bursae. The ductus bursae is narrow, evenly sclerotised. The distal part of the corpus bursae is elongate-ovate, slightly scobinate at each end, and with oblique wrinkles over the central part.

Poole (1989) listed four further species in the genus, one from each of Sri Lanka, India, Taiwan and the Philippines.