The frigida group
Externally, species are characterized by dark markings (a spot or fascia) on the costal margin of the forewing; a frontal tuft that is pure white to golden cream or dull yellow ( P. myxodes), or orange-ochre ( P. subviolacea). In the male genitalia, the uncus possesses two slender, short or long lateral lobes; the gnathos is a large plate with a distinctive, wide, spiny caudal process; and the vinculum has a distinctive, long, rod-like juxta (Fig. 1). In the female genitalia, apophyses are long; anal papillae are modified into a single, round, oval or triangular element (Fig. 1) (see Discussion); the signum is absent ( P. myxodes), weakly developed, indistinctive ( P. subviolaceae, P. similantis), or well-developed, lamellar ( P. frigida).
From other groups of Oriental Pseudopostega, the frigida group is distinguished by the combination of costal markings of the forewing, and a spiny gnathos.
Distribution. Currently the group is comprised of five species distributed in India, Nepal, Sri Lanka, Indonesia, Thailand, and Taiwan.
Remarks. Previously, P. subviolacea was left unplaced in a species group (Puplesis and Robinson 1999), but upon re-examination of the female genitalia of P. subviolacea we newly attribute this species to the frigida group because the anal papillae are modified into a single element, a character shared with other species in the frigida group.
The presence of modified anal papillae in the female genitalia makes the group distinctive (see Discussion).