Trigonocera, Becker, 1902

Grootaert, Patrick, Velde, & Isabella Van de, 2024, New long-legged flies from mangroves on Pulau Ubin (Singapore) (Insecta: Diptera: Dolichopodidae), Raffles Bulletin of Zoology 72, pp. 303-323 : 314

Key to the Southeast Asian Trigonocera with basal abdominal tergites mainly yellow. Both new species have the basal abdominal tergites largely yellow and so only comparisons with T. lucidiventris Becker, 1922 and T. specialis Becker, 1922 are required.

1. Fore tarsus with enlarged pulvilli and lacking claws. Frons shining blue-green; 2.0– 2.3 mm [Oriental: Nepal, India (West Bengal)] ........................................... T. specialis Becker, 1922

– Fore tarsus with small pulvilli and claws present..................2

2. Scape with dorsal bristles. Tergite 1 yellowish brown, abdominal segments 2 and 3 entirely yellow [ Singapore] ......................... .............................................. Trigonocera pilifer , new species

– Scape lacking dorsal bristles...................................................3

3. Tergite 1 entirely yellow, tergites 2, 3 partly yellow. Arista 2 times as long as postpedicel. Epandrial lobe very narrow. [Oriental: China (Taiwan), Laos, Thailand] ............................. ................................................... T. lucidiventris Becker, 1922

– Tergites 1–3 yellow, but all with a black apical border. Arista at most 1.5 times as long as postpedicel. Epandrial lobe broad, trapezoid [ Singapore] ...................... T. ubinensis , new species