Thysanoptyx directa (Leech, 1899) Volynkin, 2024

Volynkin, Anton V., 2024, Taxonomic review of the Thysanoptyx Hampson generic complex (Lepidoptera: Erebidae: Arctiinae: Lithosiini). II. The genus Thysanoplisna Volynkin with descriptions of seven new species from Vietnam and mainland China, Zootaxa 5506 (3), pp. 428-450 : 437

The Th. directa species-group

Diagnosis. Compared to the Th. signata species-group, two of three species of the Th. directa species-group display a moderate sexual dimorphism expressed in the considerably narrower medial forewing spot in the female. The male genital capsule structures of the two species-groups are similar and the differences are found in the vesica, which in the Th. directa species-group has a more elongate distal section with a ventral medial diverticulum bearing an additional cornutus, and a utricular dorsal subbasal diverticulum, which is trapezoidal in the Th. signata species-group. In the female genitalia, the Th. directa species-group is characterised by the lateral position of the posterior gelatinous enlargement of the corpus bursae (vs. ventral position in the Th. signata species-group), which is well-separated from the appendix bursae.