Semidalis pseudouncinata

One caught in my garden in 2017 was the first record for Norfolk. Three more were caught in my moth trap over two nights in 2020 and I caught at least 10 here in 2022.

Semidalis species are separated from Conwentzia by the size of the hindwing and from other waxfly genera (Coniopteryx and Parasemidalis in Norfolk) from details of wing venation. Only male Semidalis can be identified to species level and pseudouncinata is told from the other species, aleyrodiformis (not yet covered here as I'm yet to find one), by the shape of its paramere.

This individual was Norfolk's first. Note that the wing-venation isn't exactly as it should be. In the highlighted area of the forewing you can see that vein MCCV (the one running at 4 o'clock from the junction in the inset) is more-or-less opposite or even slightly basal to the fork of the median vein - according to Plant (1997) in Semidalis MCCV should be after (i.e. distal to) the fork in vein M or absent and basal to it in genus Parasemidalis. This is a good example of care needed in interpreting wing-venation - there is individual variation and sometimes a feature may be correct on one wing and not on the other. In this case the genitalia removed any doubt, eliminating both Parasemidalis and the other Semidalis. Note that in the photo one of the paramere arms has shifted so that the two parameres have diverged, but downwardly hooked appendage at the tip of each paramere is clearly visible (and would be lacking on aleyrodiformis).

male Semidalis pseudouncinata showing left forewing and hindwing and cleared abdomen from side, North Elmham (Norfolk, UK), 22nd August 2017

On this one you can see that vein MCCV is clearly distal to the fork in vein M as it should be, and again the semi-circular hooked appendages on the parameres are visible (although angled here so that the hook points more right than down, nevertheless clearly in the opposing direction to the upward turn of the tip of the paramere arm).

male Semidalis pseudouncinata showing right forewing and hindwing and cleared abdomen from side, North Elmham (Norfolk, UK), 15th August 2020

On this one I managed to get a clearer photo of the genitalia. Again the arms of the parameres have diverged but the curved appendages at their tips remain in place, clearly hooked in the opposite direction to the tip of the paramere arm.

male Semidalis pseudouncinata showing cleared abdomen from side, North Elmham (Norfolk, UK), 16th August 2020

The second individual caught the same night as the last:

male Semidalis pseudouncinata showing cleared abdomen from side, North Elmham (Norfolk, UK), 16th August 2020

One more after a blank year:

male Semidalis pseudouncinata showing left forewing and hindwing and cleared abdomen from side, North Elmham (Norfolk, UK), 2nd August 2022

On the next one vein MCCV joined the median vein at the fork on one wing:

male Semidalis pseudouncinata showing forewings (including close-ups showing position of MCCV), hind wings and cleared abdomen from side, North Elmham (Norfolk, UK), 20th August 2022

Here is another one where cross-vein MCCV is pretty meets vein M pretty much at its fork.

male Semidalis pseudouncinata, North Elmham (Norfolk, UK), 22nd August 2022

The next one was similar.

male Semidalis pseudouncinata, North Elmham (Norfolk, UK), 24th August 2022

2022 was a bumper year for this species in my garden with 10 males caught in my garden moth trap (plus 15 females that were very likely to be the same species). There were 11 (5 males and 6 females) in one night!

male Semidalis pseudouncinata, North Elmham (Norfolk, UK), 4th September 2022

second male Semidalis pseudouncinata, North Elmham (Norfolk, UK), 4th September 2022

third male Semidalis pseudouncinata, North Elmham (Norfolk, UK), 4th September 2022

fourth male Semidalis pseudouncinata, North Elmham (Norfolk, UK), 4th September 2022

fifth male Semidalis pseudouncinata, North Elmham (Norfolk, UK), 4th September 2022

male Semidalis pseudouncinata, North Elmham (Norfolk, UK), 5th September 2022

male Semidalis pseudouncinata, North Elmham (Norfolk, UK), 22nd August 2022

male Semidalis pseudouncinata, North Elmham (Norfolk, UK), 11th September 2023