Banded Winter Gnat Trichocera annulata

The pale yellow-banded abdomen is a characteristic feature of this species, shared only with Trichocera maculipennis (on which the yellow is at the rear of each segment, and which has a more prominent wing spot).

female Trichocera annulata showing wing, abdomen from above (a little dried up after death) and cerci, North Elmham (Norfolk, UK), 1st January 2023

This one came to light. Its wing length was 5.35mm.

female Trichocera annulata showing wing, head, mid abdomen and cerci, Wendling Beck Environment Project (Norfolk, UK), 31st October 2023

This one also came to light and proved to be a bit of a conundrum. The bands on the abdomen are the wrong way round, with yellow at the distal section of each segment and black (well, grey) at the base. This points to Trichocera maculipennis which appears to be a rare upland species so far as I can tell, so not expected in mid Norfolk. But I don't believe it is a rarity, at least not this rarity, because maculipennis also differs from annulata in having a distinct dark spot over vein r-m. This individual only has a faint dark mark here, which is normal for annulata. Stubbs also includes diagrams of each species' cerci and on maculipennis it is more strongly curved. Furthermore I found another reference which showed maculipennis with additional markings on the wings and which made mention of maculipennis having larger first segments of the antennae than other species. So I am satisfied that my insect is not maculipennis. I suppose the question of whether it is annulata with bands the wrong way round or a normally unbanded species remains, however based on the cerci diagrams in Stubbs I think it must be annulata. The only other species with similar-shaped cerci is hiemalis, however I think that is a greyer species with shorter outer wedge cells.

female Trichocera annulata showing wing, head, mid abdomen and cerci, Wendling Beck Environment Project (Norfolk, UK), 31st October 2023

When I was figuring out the insect above I couldn't work out from my previous photos how big the first antennal segment normally was on annulata, so I couldn't tell if that one was bigger or not (as it's meant to be on maculipennis). So the next morning I got this one in from the moth trap to have a look...

female Trichocera annulata showing wing, head, mid abdomen and cerci, Wendling Beck Environment Project (Norfolk, UK), 31st October 2023