Histia Hübner

Type species: flabellicornis Fabricius, Oriental Region (mainland).

The remaining two genera are members of one of the major subclades of Clade 18, the others being the large Wallacea + New Guinea clade, which includes a Sundanian group misplaced in Anarbudas (see the generic description for Boradiopsis Hering), and the small group formed of taxa misplaced in Phlebohecta and Trypanophora discussed on the specific account of “Phlobecta” viduata. The monobasic western Chinese genus Scotopais Hering is an outlier within Clade 18.

The analysis recaptured all three exemplars of Histia as a monophyletic group, sister to a clade with a monophyletic Gynautocera Guérin-Méneville placed as sister-group to the monobasic Pompelon Walker. All these genera contain species with elongated forewings and metallic blue hindwings (Yen et al., 2005). “Eterusia” raja Moore is sister to the clade consisting of the three genera. All three genera have a series of crossveins between the costa and vein Sc of the forewing, otherwise only seen in Cyclosia (p. 45) and Eucormopsis (p. 42). The shape of the sacculus in the male genitalia could also be definitive, and it has dense transverse ridges in Histia and Gynautocera, but not Pompelon. The aedeagus has a protuberance near the apex in some of the species.

In Histia, all wings are narrow, apically produced, black with paler lining to the veins, and variably extensive areas of iridescent blue or green on the hindwing, sometimes with white areas, particularly in more easterly taxa, where the production of the wings is also reduced. The antennae of both sexes are narrowly bipectinate.

The male genitalia bear some resemblance to those of Psaphis, particularly in the shape of the valves and the linear rugosity on the inner surface of the sacculus that may be homologous with the flange in the same position in Psaphis.

The genus consists of six more or less allopatric except in Sulawesi and Java species, flabellicornis Fabricius, widespread in mainland Asia to Peninsular Malaysia; libelluloides Herrich-Schäffer from Sundaland and the Lesser Sundas; eurhodia Jordan from the Philippines; dolens Druce from Sulawesi and the northern Moluccas; porphyropyga Hering, Sulawesi; nigridorsalis Röber, Java. Inoue (1992) reviewed the subspecific variation of the two more widespread species, and Owada (2008) extended these observations for the type species.

The larva of type species was illustrated by Yen et al. (2005) and Owada (2008). It is deep pink, with the primary setae on pronounced tubercles of the same colour, the most ventral row being larger than the rest. Between them in depressions are black, transversely oval patches dorsally and dorsolaterally.

Robinson et al. (2001) cited larval host plant records for Buddleja (Buddlejaceae) and Bischofia (Euphorbiaceae), but the former was for flower-feeding and may refer to the adult; the latter was definitely a larval host (Piepers & Snellen, 1902 [1903]), and was also noted by Tarmann (1992b) and Owada (2008).