Glyptobasis nigrifrons Kimmins, 1949

(Figs. 10–14)

Glyptobasis nigrifrons Kimmins 1949: 25; Ghosh & Sen 1977: 322; Sziráki 1998: 62; Chandra & Sharma 2009: 5; Bijoy & Rajmohana 2015: 29; Singh et al. 2020: 504; Suryanarayanan & Bijoy 2021: 58.

Type locality: India (Kerala).

Type material examined. Holotype male, preserved in NHMUK, was checked. / [Holo]Type // Tenmalai 500–800’ / Travancore / S. India / 11–17-X-[19]38 // Brit. Mus / 1939. 205 // Glyptobasis nigrifrons / ♂ Kim. / D. E. Kimmins det. 1947. // NHMUK 0138040011 / (Figs. 10A–C).

Additional figs.

https://data.nhm.ac.uk/object/cb63203c-b93d-4c7c-8ea1-1244988aa8a7/1700092800000

Retrieved: 18 Nov 2023 18:43:09 (UTC)

In Kimmins (1949): Travancore, Tenmalai, 500–800 ft., 11–17. X. 1938 (G. M. Henry).

Additional material examined. In coll. SERL: 1♂, 1♀ INDIA, Kerala State, Palakkad Dist. [rict], Nelliyampathy, 1196 m , (coordinates: 10°32’16.51”N, 76°42’31.57”E), 07.X.2021, leg. Suryanarayanan. T. B., SERLNR181, SERLNR182 . 1♂ INDIA, Kerala State, Malappuram Dist. [rict], Nedumkayam, 63 m, (coordinates: 11°17’32.70”N, 76°20’25.80”E) , 11.X.2021, leg. Suryanarayanan. T. B., SERLNR193 .

Diagnostic characters. Vertex, frons, and thorax densely hairy. Labrum, clypeus, frons and gena black. Mandible silvery-white. In males, 2–10 flagellar segments slightly curved, and 5–8 segments with moderately long spines. Wing tips rounded, acute. Pterostigma dark-brown. Legs short and strong. Terminalia and genitalia as in Kimmins (1949: figs 8–9) as well as in Figs. 13A–F. See the key at the end of this chapter for separating the species.

Redescription.

Measurements. Male (n=2): body length: 31–32 mm, forewing length: 35–36 mm, width: 9 mm; hindwing length: 31–32 mm, width: 7 mm. Female (n=1): body length: 28 mm, forewing length: 41 mm, width: 12 mm; hindwing length: 37 mm, width: 9 mm (Figs. 11A–B).

Head (Fig. 12A). Vertex narrow; frontal and dorsal parts dull - yellow, densely covered with long black hairs. Caudal part of vertex yellow without hairs; frons shining black, with long dense black hairs. Long, dense tuft of black hairs between scape; gena usually black on inner margin, yellow (sometimes black) on outer margin; clypeus black, with black hairs, labrum dull-black with ochreous setae directed towards mouthparts. Base of each mandible black with black hairs on lateral side. Maxillary and labial palpi dark-brown, with short brown setae and long black hairs at joints. Eyes divided by transverse furrow, lower portion slightly longer than upper portion. Antennae with scape and pedicel black, covered with long soft black hairs intermingled with some white ones; flagellomeres dull-black, with distinct lateral spines in basal flagellomeres (4–12 segments); club subglobular with flattened apex, dark-brown, with black verticils.

Thorax (Fig. 12B). Pronotum narrow, both margins bright-black, and with transverse dull-yellow stripe, posterior margin with long soft black hairs. Mesonotum and metanotum generally black, medially with broad yellow stripe, covered with long black setae.

Wings (Fig. 12C). Forewings longer than hindwings; forewing membrane completely transparent, veins brown with sparse short black setae; wing tip rounded; wing tapering basally; anal area with distinct triangular projection. Pterostigma 3x longer than wide, rhomboid-shaped, brown to dark-brown, with 6 cross-veins; apical area beyond Sc+R with three rows of cells. In front of origin of Rs with 8–9 cross-veins; Rs with 6 branches. Hindwings longer than abdomen. Membrane transparent with brown shaded cross-veins. Pterostigma 4x longer than wide, rhomboid-shaped, brown to dark-brown with 6 cross-veins; apical area beyond Sc+R with three rows of cells. In front of origin of Rs with 6–7 cross-veins; Rs with 6–7 branches.

Legs (Figs. 12D–E). Each leg short brown and hairy; coxae dark-brown with long brown and black hairs; trochanters with short dense black hairs; femora dark-brown and slightly shorter than tibiae, with short and long black hairs; tibiae dark-brown with short and long black hairs; foreleg, tibial spurs as long as t1–t2, tarsomeres with short black setae, t1–t4 nearly equal in length, t5 as long as t1–t4 combined. Tibial spurs of hindlegs shorter than length of t1, tarsomeres with short black setae, t1 longer than t2; t2–t4 nearly equal in length, t5 shorter than combined length of t1–t4.

Abdomen. Shorter than wings. Tergites dark-brown with alternating, rounded dull-yellowish spots, covered with short black setae; sternites dark-brown with short black hairs.

Male terminalia and genitalia (Figs. 13A–D). Tergite 9 somewhat quadrate, brown with black hairs. Ectoproct brown sparsely covered with short black hairs. Ectoproct processus short and thick directed ventrally with stout apices covered with long, stiff bristles. In ventral view, base of sternite 9 considerably wider than long, tip pointed, subacute. Gonocoxite 9 hood-like with pair of long narrow evenly curved horn-shaped extensions, apices acute, slightly wider at base without protuberance as viewed in ventral view.

Female terminalia (Figs. 13E–F). Tergite 9 nearly quadrate, dominantly yellow with dark-brown mark ventrocaudally covered evenly with short black hairs. Ectoproct oval brown plate, covered with dense black hairs caudally and ventrally. Gonocoxites 8 finger-like brown with short black setae, gonocoxites 9 small hemispherical with black hairs in lateral view.

Distribution. India (Kerala) (Fig. 21).

Flight period and habitat of adult. During the day, adults perch on short blades of grass alongside water bodies in forested areas, which are surrounded by small grasses, mature trees and bushes (Figs. 14A–B). The seasonality and flight activity of the imago is from September to October based on previously published literature. In Kerala, based on the field collection data, the species is mainly active in October, indicating that it is highly seasonal (Fig. 22).