Sphegina (Asiosphegina) hamulata sp. nov.

urn:lsid:zoobank.org:act: 27D750EC-4C1C-4D05-B742-F34748CBE9ED

Figs 38I, 40, 41D

Differential diagnosis

Sphegina (Asiosphegina) hamulata sp. nov. is not especially similar to any other known Sphegina and is easily distinguished by the characters mentioned in the key. It resembles a number of those species which have strong setae posteriorly on male sternum IV, but the setae are all pale (in the other species at least a number of them are black). In addition, the sternum is almost symmetrical (distinctly asymmetrical), except for the submembranous flange posteriorly from the setae which is situated on the left side. The asymmetrical surstyli with the right-side one wider than the left-side one occur commonly in this group. The narrow hook-shaped left surstylus is unique.

Etymology

The specific epithet is from the Latin ‘ hamulata ’, meaning ‘with a little hook’ and referring to the posteriorly hooked right side surstylus.

Material examined

Holotype

INDIA • ♂; “India, W.B. [West Bengal] / Rangiroon 6500’ [ft] / 24.V 1962 / [leg] Gupta ”; “ Ghorpade / Collector / Bangalore”; USNM.

Description

Male

LENGTH. Body 6.0 mm, wing 4.6 mm.

HEAD. Face in lateral view concave, weakly projected antero-ventrally; frontal prominence weakly developed. Ratio width of vertex at anterior ocellus: width of head 1: 3.8; ratio width of ocellar triangle: width of vertex 1: 2.2; ratio length of ocellar triangle: length of frons 1: 2.2. Face black, light grey pollinose long pilose along eye-margin. Hypostomal bridge black, long pale pilose. Gena and mouth edge black with large subtriangular non-pollinose shiny area. Frons and vertex black, slightly pollinose, a semi-circular area posterior of lunula non-pollinose and shiny (Fig. 38I); pile short, light yellow. Frons with deep pit anteromedially and wide but weak medial furrow. Occiput black, light grey pollinose, light yellow pilose. Eye without enlarged facets at anterior margin. Antenna with scape and pedicel black, basoflagellomere dark brown, with black setae dorsally on scape and pedicel; basoflagellomere oval, ratio width: length 1: 1.1; arista long pilose, about 2.5 times as long as basoflagellomere.

THORAX. Colour black, weakly greyish pollinose, pleuron entirely more heavily grey pollinose; scutum and pleuron with very short adpressed light yellow pile. Scutellum crescent-shaped, black, grey pollinose, with pile slightly longer than on scutum, with two closely set, short setae, as long as length of scutellum.

WING. Entirely microtrichose; hyaline, stigma yellowish. Crossvein dm-cu meeting vein M obliquely and vein M 1 meeting vein R

4+5

perpendicularly.

LEGS. Pro- and mesoleg yellow, protarsus entirely black, mesotarsus with tarsomere 2 brown and tarsomeres 3–5 black. Metaleg with coxa black, trochanter yellow; femur black with basal ⅓ yellow, slightly incrassate, ratio width: length 1: 4.2; tibia black and yellow biannulate, with short rounded apicoventral dens; tarsus entirely black, basitarsomere rather thin, ratio width: length 1: 3.8.

ABDOMEN. Length ratio of terga I: II: III: IV 1: 3.7: 2.1: 1.8; ratio width at posterior margin: medial length of tergum II and III 1: 4.3 and 1: 1.1. Terga black, anterior ¼ of tergum III with yellow fascia; pile pale, on terga short, laterally on terga I and II long; tergum I with 2 widely separated strong light-brown setae at lateral margin; sternum III squarish, ratio width: length 1: 1.5; sternum IV, Fig. 40A; sterna VI, VII and VIII simple, with long yellow pile. Genitalia, Fig. 40 B–D: note the asymmetrical surstyli and superior lobes.

Female

Unknown.