Hydrotaea dentipes, Fabricius, 1805

Vikhrev, Nikita E., 2024, Review of Hydrotaea dentipes species group (Diptera, Muscidae), Amurian Zoological Journal XVI (4), pp. 1008-1020 : 1018-1019

Key for the Hydrotaea dentipes group, ♂♂

1. Eyes bare ( Fig. 5, except for H. kashmirana and H. villosa with short and sparse hairs as in Fig. 6). t3 without pv setae. f 2 in basal half without straight, strong, and spinulose v-pv setae (except H. similis )............ 2

— Eyes covered with long and dense hairs as in Fig 7. t 3 with a row of several pv setae (about as long as tibia width). f 2 in basal half with straight spinulose v-pv setae, which are distinctly stronger than a-av setae (except H. maculithorax )........... 9 ( H. cyrtoneurina clade)

2. Mid coxa on hind inner margin with a close-set cluster of 3–4 blunt spinulose setae (Fig. 10). t2 with 2 strong ad in apical half. Abdomen densely grey dusted with distinct black median vitta. Frontal vitta wider than width of postpedicel. (Prealar seta absent or very weak. Notopleuron bare around post ntp seta. f 2 in basal half with shorter (at most 2x femur width) and sparser outcurved a and av setae than in H. dentipes . t2 without row of short stubbly ad hairs. f3 with fine ventral setae dense but short, at most as long as femur width. t3 with about 3 av.).............. palaestrica Meigen

— Mid coxa without modified setae. t2 without strong ad (except H. anxia with 1 ad). Abdomen only finely grey dusted with less distinct median vitta. Frontal vitta narrow- er ................................... 3

3. Apex of t3 with ventral tuft of short, dense setae as in Fig. 9. f2 with long and dense outcurved a and av setae in basal half, those 2–3x as long as femur width. (Frontal vitta slightly narrower than width of postpedicel. Prealar seta absent. Notopleuron bare around post ntp seta. f2 with straight pv setae fine, but dense and long. t2 without strong ad; with a row of short stubbly ad hairs. t3 with about 3 av.)........... 4

— t3 without ventral tuft at apex. f2 with outcurved a and av setae shorter in basal half..................................... 5

4. f 3 in basal half with fine ventral setae as long as femur width. Apical tuft on t3 less distinct. Holarctic......... dentipes Fabricius

— f 3 in basal half with only short setulae. Apical tuft on t3 more distinct (Fig 9). Nearctic....................... cristata Malloch

5. t3 with 6–8 long av. Prealar seta absent. Notopleuron hairy around post ntp seta. Body length usually more than 8 mm. (Frontal vitta narrow, almost linear. f2 with shorter (at most 2x femur width) and more srarce outcurved a and av setae in basal half. t2 without strong ad seta. f3 with ventral setae fine and sparse but longer than femur width.).............................. 6

— t3 with 2–3 av. Prealar seta present. Notopleuron bare or hairy around post ntp seta. Body length usually less than 8 mm ...... 7

6. Eyes bare ( Fig. 5). Calypters whitish-yellow. f2 with pv setae strong and spinulose. Palaearctic................. similis Meade

— Eyes hairy, though with rather short and sparsely hairs ( Fig. 5). Calypters light brown. f2 with pv setae fine. N India & Nepal................... kashmirana Pont

7. t2 with 1 ad near apex; without short stubbly a hairs. Presutural part of scutum undusted. One prealar seta. (Notopleuron hairy around post ntp seta. Frontal vitta linear. Body with greenish or bluish metallic tint.) Circumpolar Holarctic species...................... anxia Zetterstedt

— t2 without ad near apex; with a row of short stubbly ad hairs. Two prealar seta. N or S America.............................. 8

8. Notopleuron bare around post ntp seta. Eyes bare or almost so. Body without metallic tint. Nearctic....... houghi Malloch

— Notopleuron hairy around post ntp seta. Eyes hairy. Body with metallic tint (Fig. 8). Neotropical................ villosa Stein

9. Thorax with Anthomyia -pattern (Figs 2–4): grey dusted, with 3 presutural and 3 postsutural dark spots. t2 near apex with ad seta or av setae. Abdomen densely grey dusted............................. 10

— Thorax without Anthomyia -pattern, glossy black. t2 without anterior seta(e). Abdomen with only fine grey dusting....... 11

10. Body length usually 7–7.5 mm. Thorax (Fig. 12) with an indistinct Anthomyia - pattern: dirty black spots on dirty dark grey background with vague borders; postsutural median and lateral spots not fused. Notopleuron densely hairy. t 2 in apical quarter with 1 short, strong ad. f 2 in basal half with two rows of strong, spinulose v setae. Distance between eye margins more than width of antenna. Fronto-orbital plates entirely matt.................... fasciata Stein

— Body length 6 mm. Thorax (Fig. 13) with a distinct Anthomyia -pattern; postsutural median and lateral spots fused in black transversal band. Notopleuron bare. f 2 in basal half without rows of spinulose v, only with fine setae. t 2 in apical quarter with a row of 5–6 fine, longer av. Distance between eye margins less than width of antenna. Fronto-orbital plates partly shining.................... maculithorax Stein

11. Calypters yellow. Wings with yellowish tint. (♀: frontal triangle and fronto-orbital plates dusted.) Palaearctic and N Oriental............... cyrtoneurina Zetterstedt

— Calypters dark brown. Wings with brownish tint. (♀: frontal triangle and fronto-orbital plates glossy.) Afrotropical....................... fumifera Walker