On the taxonomy of the genus Eugoa Walker, 1858, with descriptions of two new species from Laos and Vietnam (Lepidoptera, Erebidae, Arctiinae, Lithosiini)

Two new species of the genus Eugoa Walker, 1858, Eugoa dubatolovi Volynkin, Bucsek & Černý, sp. nov. (South Laos and South Vietnam) and Eugoa sinxayi Volynkin, Bucsek & Černý, sp. nov. (Central Laos) are described. Both new species are related to Eugoa zolotuhini Dubatolov & Bucsek, 2016 and Eugoa hainanensis Fang, 2000. Adults and male genitalia of the new and related species are illustrated.

During studies of Lithosiini materials from Laos and Vietnam, we found two more, yet undescribed species of Eugoa.The descriptions of the new species are presented below.

Material and Methods
The genitalia were dissected and mounted in euparal on glass slides.Photos of imago where taken using the camera Nikon D3100/AF-S Nikkor, 18-55 mm.Genitalia images were taken by the same camera attached to a microscope with an LM-scope adapter.
Abbreviations used: AV = genitalia slides prepared by Anton Volynkin; CAV = private collection of Anton V. Volynkin (Barnaul, Russia); CKB = private collection of Karol Bucsek (Bratislava, Slovakia) 3) can be easily distinguished from E. zolotuhini (Fig. 5) by its larger size, darker forewing ground color, much broader antemedial line of forewing interrupted into two broad dark spots, posteriorly broader postmedial line, and well developed subterminal line; from E. hainanensis (Fig. 6) it differs by the larger size and much broader antemedial line of forewing interrupted into two broad dark spots.The male genitalia of E. dubatolovi sp.nov.(Figs 7-9) differ from those of E. zolotuhini (Fig. 11) by the uncus much broader basally and medially, broader penicular lobes, much longer juxta, much larger, trigonal dorsal lobe of sacculus with less setose dorsal margin (whereas in E. zolotuhini the dorsal lobe of sacculus is much narrower, finger-like, heavily setose), broader apex of valva, larger subapical ventral process of valva, broader subbasal ventral diverticulum, absence of medial dorsal diverticulum, much smaller and slightly C-like curved apical diverticulum, and presence of a row of 3-5 short cornuti in the medial section of vesica (whereas in E. zolotuhini the subbasal ventral diverticulum is narrower, the medial dorsal diverticulum is present, the apical diverticulum is much larger, S-like curved, and there are only two short cornuti in the medial section of vesica); from those of E. hainanensis (Fig. 12) the male genitalia of E. dubatolovi sp.nov.differ by the basally narrower and dorso-ventrally flattened uncus, narrower penicular lobes, dorsally curved distal section за valva, much larger, trigonal dorsal lobe of sacculus, much larger, round apex of valva, much smaller, trigonal subapical ventral process of valva, smaller subbasal ventral diverticulum, absence of medial dorsal diverticulum, much smaller and slightly Clike curved apical diverticulum, and presence of a row of 3-5 short cornuti in the medial section of vesica, whereas in E. hainanensis the basal section of uncus is broader and inflated, the penicular lobes are broader, the distal section of valva is straight, the dorsal lobe of sacculus is smaller, rounded, the apex of valva is small, thorn-like, the subapical ventral process of valva is large, rounded, the subbasal ventral diverticulum is much broader, the medial dorsal diverticulum is present, the apical diverticulum is much larger, S-like curved, and there are only two small cornuti in the medial section of vesica.The differences between E. dubatolovi sp.nov.and E. sinxayi sp.nov.are listed in the diagnosis of the latter.-8.Eugoa spp.: adults.1, E. dubatolovi, holotype male, S Laos (NHMUK); 2, E. dubatolovi, paratype male, S Vietnam (CKC); 3, E. dubatolovi, paratype male, S Vietnam (CAV); 4, E. sinxayi, holotype male, C Laos (MWM/ZSM); 5, E. zolotuhini, holotype male, N Vietnam (SZMN); 6, E. hainanensis, male, S Laos (CAV).1-3).Forewing length 10.5-12 mm.Male antennae bipectinate.Head and thorax dark brown; tegula with large blackish spot; abdomen ochreous brown.Ground color of forewing pale grayish brown, with strong dark brown suffusion.Pattern blackish brown.Basal line interrupted into broad costal spot and short and thin medial stroke; antemedial line broad, interrupted into two large spots; postmedial line S-like curved, strongly broadened at costa and anal margin; subterminal line thin, diffuse, broken; two blackish dots in cell; cilia pale brown, with row of blackish brown dots between veins.Hindwing pale brown with grayish suffusion; cilia pale brown.Male genitalia (Figs 7-9).Uncus spearheadlike, dorso-ventrally flattened; tuba analis membranous, scaphium narrow, weakly sclerotized, subscaphium weakly setose; tegumen short, penicular lobes medium-broad, rounded; juxta large, trapezoidal, with small apical medial concavity; vinculum very short, U-like.Valva elongated, distally slightly narrowed and dorsally curved; broad row of strong hair-like setae in medial area of valva; apex of valva heavily sclerotized, broad, rounded; subapical ventral process of valva trigonal, apically pointed, directed ventrally; sacculus broad, its basal lobe large, broadly trigonal, apically tapered, setose, extends beyond costal margin.Aedeagus medium-long, proximally broadened, slightly curved distally; vesica broad, membranous, with membranous, broad and round subbasal ventral diverticulum, granulated, broadly conical medial ventral diverticulum, granulated, round medial lateral diverticulum, and membranous, finger-like apical diverticulum; row of three-five thorn-like cornuti of different size medio-laterally; vesica ejaculatorius directed dorsally.

Description. Adult (Figs
Female unknown.
Distribution.The species is known from South Laos and South Vietnam.
Etymology.The species" name is dedicated to Dr. Vladimir V. Dubatolov (Novosibirsk, Russia), a famous expert in the Arctiinae taxonomy.Diagnosis.Eugoa sinxayi sp.nov. is a sister species of E. dubatolovi sp.nov.Externally the two species are very similar (Figs 1-4), only pattern elements of E. sinxayi sp.nov.seem to be slightly paler, brown.The main differences between these species can be found in the male genitalia structures: in E. sinxayi sp.nov.(Fig. 10) the uncus is narrower basally than that of E. dubatolovi sp.nov., the penicular lobes are shorter, with more smoothly curved margins, the juxta is longer, the basal lobe of sacculus distally narrower and rounded, the apex of valva is slightly longer, apically dentate, the subbasal lateral diverticulum is much broader, the medial lateral diverticulum is broader and weaker granulated, the medial ventral diverticulum is much longer, the apical diverticulum is narrower.
Female unknown.Distribution.The species is known only from Central Laos.