Tactusa Fibiger, 2010

FIBIGER, MICHAEL, 2010, Revision of the Micronoctuidae (Lepidoptera: Noctuoidea) Part 3, Taxonomy of the Tactusinae, Zootaxa 2583 (1), pp. 1-119 : 13-14

Genus Tactusa Fibiger , new genus

Type-species: Tactusa sumatrensis Fibiger , new species.

Taxonomic notes. The genus Tactusa includes 27 known species, placed in 4 species-groups: T. major species-group; T. trigonifera species-group; T. nieukerkeni species-group and T. artus species-group. Except that they share several prominent structural features, they are regarded as modifications within the generic ground plan of the genus. With only a few exceptions, the species can be recognised only by structures in the male and female genitalia.

Diagnosis. Character states of Tactusa generally defined above, in subfamily Tactusinae and tribe Tactusini diagnoses; apomorphies for Tactusa indicated by (apo.);

Imago (external). Thorax, tegulae and ground-colour of forewing: light yellowish brown, forewing often with a well-marked quadranglar or triangular costal patch between antemedial and postmedial lines.

Reniform stigma: outlined by large costal patch; often difficult to observe.

Hindwing: dark greyish; with brown terminal line and indistinct discal spot; without medial line.

Male genitalia. Tegumen: narrow, considerable narrower than vinculum and saccus (apo).

Vinculum: strongly built.

Saccus: short; strongly built, broadly U shaped.

Fultura superior: membranous.

Valva: asymmetrical.

Ampulla: more or less forming a cross with axis of valva; elongated and narrow (apo.) (shorter by T. ostium ); convex by valva; distal edge concave; some species distally with short, stout spines, and with differently shaped inner and outer edges.

Digitus: usually absent; present in one species group.

Juxta and anellus plate: totally fused, with hole for phallus; slightly asymmetrical.

Phallus: long; coiled clockwise, tapered towards apex; coecum upturned only in type-species); with humps subbasally; almost straight until strong coil subterminally in a few species; subapically with a prominent, long spine, also in a few species; some species with a shorter straight cylinder; and some with less prom-

Female genitalia. Ovipositor: quadrangular with rounded corners.

Anterior apophyses: longer than posterior apophyses (apo.).

Ostium: displaced to left.

Antrum: cylindrical; short; narrow; heavily sclerotised (apo.).

Ductus bursae: membranous, long, narrow; slightly coiled.

Appendix bursae: arising anteriorly from ductus bursae, immediately posterior to antrum.

Corpus bursae: globular.

Signum: cross shaped.

Differential diagnosis. Species of Tactusa differ from those of Obscura in elongated shape of ampulla; in anterior apophyses being shorter than ovipositor; and in short, narrow, cylindrical antrum.

Distribution. Genus occurs in tropical and subtropical areas of SE Asia and Oriental regions.