Ngirhaphium Evenhuis & Grootaert, 2002

Grootaert, Patrick & Puniamoorthy, Jayanthi, 2014, Revision of Ngirhaphium (Insecta: Diptera: Dolichopodidae), with the description of two new species from Singapore’s mangroves, Raffles Bulletin of Zoology 62, pp. 146-160 : 147

Genus Ngirhaphium Evenhuis & Grootaert, 2002

Ngirhaphium Evenhuis & Grootaert, 2002 , Raffles Bulletin of Zoology, 50: 310.

Type species by original designation: Ngirhaphium murphyi Evenhuis & Grootaert, 2002 .

Diagnosis. Medium-sized species with a metallic green or blue ground-colour. Antenna very long in males, a little shorter in females. Arista apical, basal aristal segment long; length apical aristal segment specific. Rostrum in male small with well-developed labellae. Rostrum very large in female. Face wide, clypeus only a narrow strap in male; very long in females, pointed. Vertex excavated (cf. Sciapodinae ) and ocellar tubercle much raised above frons. The ocellar bristles are very long and with a thick socket on ocellar triangle.

Thorax with biserial acr; dc multiseriate in front of suture, further uniserseriate ending in 2 long prescutellars. A pair of long scutellars. A group of short upper propleurals and 2 longer lower propleurals.

Fore legs much shorter than mid and hind legs. No exterior bristle on mid and hind coxae. Hind coxae bare. Femora without conspicuous bristling. All tibiae with strong bristles. Fore leg in male with tarsomere 4 with an asymmetrical apical dorsal protuberance (absent in female); terminal segment with a pair of normal claws and a thickened claw-like structure beneath the posterior claw. Female with the claws as usual, but the terminal segment bears a long dorsal protuberance. Mid and hind legs with tarsal segments 1–4 with an apical comb of short spinules.

Wing with tip of vein M 1+2 sharply bent upward just before reaching the wing border and ending near tip of vein R 4+5.

Differential diagnosis. The genus resembles Rhaphium , especially the species R. longicorne (Fallén) . Both genera have short fore tarsi. Rhaphium has the fore tarsomeres 4 and 5 normally shaped, has no apical comb of spinules on the tarsal segments 1–4 of the mid and hind legs. Vein M 1+2 can converge a little to R 4+ 5 in Rhaphium , but in Ngirhaphium the vein M 1+2 bends up sharply before the tip of the wing and eventually ends close to R 4+ 5 in the wing tip.

Key to males of Ngirhaphium from Singapore:

1. Mesonotum and tergites shining metallic blue. Large species (7–8 mm) with apical aristal segment filiform and much longer than basal aristal segment ........... N. caeruleum , new species

– Mesonotum and tergites shining metallic green. Medium-sized species (4.5–7.3 mm) with apical aristal segment shorter or about half as long as apical aristal segment ....................... 2

2. Wing membrane not infuscate. Apical aristal segment about half as long as basal aristal segment. Cerci fused and tips are protruding from tips of surstyli ( Figs. 4, 5 ) ............................ .......................................... N. murphyi Evenhuis & Grootaert

– Wing membrane infuscate brown or black with longitudinal veins and Tp dark seamed. Apical aristal segment broad at base and tapering toward apex, nearly as long as basal aristal segment in male, sometimes a little longer in female. Tip of dorsal surstylus truncate, very wide and darkened ( Figs. 9, 10 ) ................................................. N. sivasothii , new species

Figures

Figs. 4–5. Ngirhaphium murphyi, Evenhuis & Grootaert: 4, Dorsal view of genital capsule; 5, Lateral view of genital capsule with left ventral surstylus removed, hypandrium at the front, right ventral surstylus at the back.

Figs. 9–10. Ngirhaphium sivasothii, new species (Semakau, Singapore): 9, Lateral view of genital capsule with left ventral surstylus at the front; 10, Dorsal view of cerci.