Hydrotaea meteorica, Linnaeus, 1758

Vikhrev, Nikita E., 2023, Review of the Hydrotaea meteorica group (Diptera, Muscidae), Amurian Zoological Journal XV (4), pp. 838-846 : 845-846

Key to the females of the Hydrotaea meteorica group

1. Paleotropical. Small, body length about 3 mm. No minute setulae between outer ac setae. Frons distinctly narrower than 1/3 head width. (Notopleuron bare. Parafacials and fronto-orbital plates entirely dusted. t3 without or with very short pd.).................................. nigribasis Stein

— Body length about 4–5 mm. Surface between outer ac setae covered with minute setulae................................ 2

2. Oriental. Upper parafacial glossy black... ....................................... 3

— Palaearctic. Parafacial and fronto-orbital plates entirely dusted. (Notopleuron with hairs. t3 with 1 pd and 1 ad.)........... 5

3. Notopleuron bare. t3 without pd. Frons narrower than 1/3 head width. Fronto-orbital plates mostly glossy black.............. 4

— Notopleuron with hairs. t3 with ad and pd. Frons wider than 1/3 head width. Fronto-orbital plates dusted........................................ cilifemorata Emden

4. Arista whitish in second quartre. Aristal hairs shorter than base of arista. t3 with ad ...................... spinigena Xue & Li

—Arista entirely dark. Aristal hairs as long as base of arista. t3 without ad. (Apart from Oriental realm, this species is known from SE Palaearctic.).............. affinis Karl

5. Knob of halters always brown. Notopleuron with hair(s) near posterior seta............................. meteorica Linnaeus

— Knob of halters yellow. Notopleuron without hair(s) near posterior seta........................ cinerea Robineau-Desvoidy