Affiliated to the British Entomological and Natural History Society (BENHS)
You are not logged in.
This fly was caught inside the house towards the end of January. I have found H. rotundicornis before and it is clearly different in frons and face width. I have the key of Godurov (1988) but the British key of Collin (1943) does not seem to be readily available.
The key to genera is rather cryptic, but assuming it IS Heteromyza, then the pre-sutural dc rules out H. oculata. That leaves H. atricornis and H. commixta. Having looked at the British checklist and also on Diptera.info, I found there is some confusion about whether H. atricornis has been recorded in Britain - this name was formerly wrongly applied to H. rotundicornis, but the species may have been recorded recently in Shetland.
Returning to the key the question is whether the frons is "anteriorly tapered only slightly" (atricornis) or "anteriorly tapered gradually" (commixta).
So I would be grateful both for clarification on the British status of H. atricornis and whether my photos show H. commixta.
Hi Phil - don't know if it helps but the relevant Collin 1943 reads
1(6) dc before suture well deveoped
2(3) In male frons anteriorly tapered only slightly. Body 6-7mm. H.atricornis Mg.
3(2) In male frons anteriorly tapered gradually
4(5) In male face narrower than frons in middle. Body 4-5mm. H.rotundicornis Ztt
5(4) In male face not narrower than frons in middle. Body 6.0mm H.commixta Collin