Dolgoma Moore, 1878

Volynkin, Anton V. & Černý, Karel, 2021, Taxonomic review of the genus Dolgoma Moore (Lepidoptera: Erebidae: Arctiinae) from Thailand with descriptions of three new species, Zootaxa 5060 (3), pp. 417-428 : 418

Genus Dolgoma Moore, 1878

Dolgoma Moore, 1878 , Proceedings of the Scientific Meetings of the Zoological Society of London, 1878, 20.

Type species: Lithosia reticulata Moore, [1866] (by original designation).

Dolgma: Černý & Pinratana (2009), misspelling.

Diagnosis. In the male genitalia, the apex of the distal saccular process is short (from 1/12 to 1/7 of the sacculus length), dilated, heavily sclerotized and armed with spinules (an autapomorphic feature) while in the similar Teuloma and Teulisna Walker it is elongate and curved. Additionally, the vinculum of Dolgoma is short (ca. 1.4–1.7 times shorter than the tegumen), more or less V-shaped, moderately sclerotized and lacking coremata while in Teuloma and Teulisna it is more elongate, more or less rectangular, weakly sclerotized and has coremata. In the female genitalia, the presence of a large, sack-like lateral diverticulum of the appendix bursae is characteristic for the genus ( Dubatolov & Zolotuhin 2011; Singh et al. 2019).

Redescription. External morphology of adults. Sexual dimorphism limited: female somewhat larger than male, slightly darker colored and has slightly narrower forewing. Forewing length 6.5–14 in males and 7–16 mm in females. Antenna sparsely ciliate in both sexes. Body and forewing coloration from pale yellow to dark brown in different species. Forewing costa convex subapically. Forewing pattern represented by diffuse postmedial line angled medially or longitudinal stripes or reduced in certain species. Additionally, suffusion of numerous small dark spots may be present. Hindwing paler than forewing, without ornamentation. Male genitalia. Uncus dilated medially or subdistally, tapered distally with tiny claw-like pointed tip, in certain species with thin crest dorsally. Tuba analis membranous. Arms of tegumen dilated posteriorly, fused in distal third. Vinculum ca. 1.3–1.5 times shorter than tegumen, with short and more or less V-shaped saccus. Valva elongate and narrow (length to width ratio from 2.8:1 to 3.8:1), somewhat dilated subdistally, with rounded apex. Sacculus narrow (from 1/4 to 1/3 of valva width). Distal saccular process short, dilated, heavily sclerotized and armed with spinules. Juxta consists of thin sclerotized crests connected by wide membranous commissures. Phallus somewhat dilated proximally; its width varies in different species groups. Vesica globular, with membranous distal diverticulum and lateral diverticulum bearing cluster of numerous tiny spine-like cornuti. Vesica ejaculatorius projected ventrad. Female genitalia. Papilla analis trapezoid with rounded corners, weakly setose. Apophyses elongate and thin, apophysis anterioris shorter than posterioris one. Ductus bursae short (in proportion to ovipositor length), dorso-ventrally flattened, its posterior section of ductus bursae sclerotized with oblique anterior margin, anterior section significantly shorter and membranous. Posterior section of corpus bursae fully or laterally sclerotized. Anterior section of corpus bursae markedly broader than posterior one, more or less globular, membranous with one or two round signa. Appendix bursae positioned postero-laterally and projected anteriad, its proximal section sclerotized while anterior one broader, membranous, with distal end directed inwards and sack-like diverticulum directed anteriad.

Remarks. The male genitalia of species of the genus are rather uniform within species groups and interspecific differences are relatively minor. However, in addition to the external appearance, diagnostic features can be found in the valva proportions, the shape and size of the distal saccular process and the vesica structure. On the basis of the male genitalia structures, the genus was subdivided by Singh et al. (2019) into three species-groups two of which are present in Thailand.