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Plotheia Walker

Type species: decrescens Walker, Sri Lanka.

Synonym: Cryptothripa Hampson (type sp
ecies occulta Swinhoe, India), syn. Ochrothripa Hampson (type species leptochroma Turner, Australia) may also be referable (see below).

This genus is available for a number of species previously assigned to Gadirtha that have distinctive features of the male genitalia such as more elongate, entire valves and striking development of what appear to be socii on the uncus, bearing dark spines at their apex. The uncus is relatively long and slender, sometimes apically bilobed or bifid. The tegumen is also more elongate and, in the type species of Cryptothripa and an undescribed species from Java and Bali (slide 16865), has slender, sinuous, digitate processes on each side, and there are shorter, broader ones in the type species of Plotheia. In
exacta Semper the tegumen is distinctly broadened on each side but lacks processes. The aedeagus is simply curved, the vesica rather globular, and there may be development of a juxta.

The female genitalia have a short, sclerotised ductus and often a very elongate bursa within which the paired, spined bands are elongate and rather weak or absent. The bursa may have a small, spherical appendix, separated by a narrow constriction.

The species are generally smaller than those in Gadirtha and have a distinctive greenish forewing facies with a paler apical patch similar to that of Arachnognatha in the Ariolicini.

As well as the species noted above and below, the genus also includes P. trichocera Hampson comb. n. (New Guinea), P. albivenosa Prout comb. n. (New Guinea) and probably P. muscosa Fletcher comb. n. (Solomons: Rennell I.). The South African species, P. polyhymnia Hampson, has female genitalia typical of the Iscadia group, but more robust than in Oriental species. Two Australian species may also be referable to Plotheia, but no males were available for examination: “Iscadia” poliochroa Hampson; Ochrothripa leptochroma Turner.

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