Conwentzia psociformis

Conwentzia psociformis

The two Conwentzia species are readily separated from nearly all other British waxflies by their very small hindwings (much smaller than their forewings), although seeing this when in resting position isn't so easy. The genus Helicoconis shares small (if not so narrow) hindwings but these are not known from Norfolk (or anywhere in England so far as I know).

Conwentzia psociformis is common in Norfolk, but needs to be separated from the scarcer Conwentzia pineticola. It would be particularly worthwhile to check any Conwentzia that appear to be associated with pine as these are more likely to be pineticola.

This species flies between late April and mid September.

male Conwentzia psociformis, North Elmham (Norfolk, UK), 2nd May 2019

Male Conwentzia can be identified by looking at their genitalia after macerating the abdomen (I use 10% potassium hydroxide). You need to view the abdomen end-on and there are two characters you need to look for. The parameres (red arrows in the image below) diverge more widely in pineticola, but be careful here as I find that in psociformis they can shift when the abdomen is cleaned if you're not very careful, causing them to diverge more widely than they sit naturally. Even with care, they can diverge more widely than shown in the figure in Plant (1997). I therefore find the second character more helpful, the tips of the ectoprocts which extend from the sides of the abdomen towards the parameres in the centre (blue arrows in the image below). The tips are obviously forked in pineticola but only slighly bifurcate in psociformis.

male Conwentzia psociformis, North Elmham (Norfolk, UK), 3rd September 2021

In the above image the parameres diverge slightly more than you might perhaps expect but you could be forgiven for identifying the next individual as pineticola based on the parameres. However the tips of the ectoprocts clearly pointed to psociformis.

male Conwentzia psociformis, North Elmham (Norfolk, UK), 1st May 2018

In this one the parameres are only slightly divergent, just as they're supposed to be on psociformis.

male Conwentzia psociformis, North Elmham (Norfolk, UK), 1st May 2018

Unusually for a waxfly, this one was identified while it was still alive. Admittedly it was only just alive, lacking the energy to right itself when laid on its back and on an incline to allow visibilty up the 'tail'. The parameres were easily visible (and show in the photo) and the ectoprocts were also just visible through the microscope (but haven't come out clearly in the photo).

male Conwentzia psociformis, Wendling Beck Environment Project (Norfolk, UK), 7th May 2023

Although you shouldn't ever confuse Conwentzia with Coniopteryx or Semidalis because of the size of the hindwings, if for any reason you do need to use abdominal characters alone then it might help to know what Conwentzia looks like from the side - a view that isn't given in the FSC guide.

male Conwentzia psociformis, North Elmham (Norfolk, UK), 1st August 2022

male Conwentzia psociformis, Wendling Beck Environment Project (Norfolk, UK), 7th May 2023

2x male Conwentzia psociformis, North Elmham (Norfolk, UK), 1st July 2023

male Conwentzia psociformis, North Elmham (Norfolk, UK), 1st July 2022

male Conwentzia psociformis, North Elmham (Norfolk, UK), 3rd July 2022

male Conwentzia psociformis, North Elmham (Norfolk, UK), 29th April 2023

male Conwentzia psociformis, North Elmham (Norfolk, UK), 17th August 2022

male Conwentzia psociformis, North Elmham (Norfolk, UK), 19th August 2023

male Conwentzia psociformis, North Elmham (Norfolk, UK), 24th September 2023

male Conwentzia psociformis, North Elmham (Norfolk, UK), 25th June 2023

male Conwentzia psociformis, North Elmham (Norfolk, UK), 28th June 2023

male Conwentzia psociformis, North Elmham (Norfolk, UK), 28th July 2023

male Conwentzia psociformis, North Elmham (Norfolk, UK), 17th June 2022

2x male Conwentzia psociformis, North Elmham (Norfolk, UK), 11th July 2022

Female Conwentzia species are thought to differ in their number of antennal segments with psociformis having between 36 and 43 segments on each antenna and pineticola having between 28 and 36 segments. So far as I know it has not yet been established whether this character is reliable, so females can only be identified provisionally.

I am happy to receive records of female Norfolk Conwentzia provided the number of antennal segments is recorded (and preferably any association with either pine or decidious trees). Even if the records are currently provisional it may be possible to upgrade them in future. Ideally you should count the segments on both antennae as they can differ slightly and it helps to eliminate the risk of a low count being a result of damage to the antennae.

This female had 40 segments on each antenna so was presumably psociformis:

probable female Conwentzia psociformis, North Elmham (Norfolk, UK), 27th April 2018