Cacopsylla rhamnicola

Previously known as Psylla rhamnicola but now placed in the genus Cacopsylla. I'm grateful to James Emerson (county recorder for jumping plant lice) for confirming that the individual featured below is the first record for Norfolk.

This was one of several psyllids beaten from the lower branches of a pine tree. Although the plant association of rhamnicola is Buckthorn, many psyllids that aren't associated with conifers nevertheless overwinter in conifers. I didn't notice if Buckthorn grows in the immediate vicinity, but it grows much more abundantly in the Brecks generally than it does in most of Norfolk, so it's likely to be growing fairly nearby.

It keyed to genus Psylla (sensu lato) fairly straightforwardly using the RES key. It seemed to have a dark spot along the wing edge near the clavus which caused me to consider pyricola, but on closer inspection this was positioned basal to the end of the clavus not over it, and the appearance of a spot was caused by a darkened thickening of the anal vein rather than dark pigment on the membrane, and possibly exaggerated by darkening in the same area on the hindwing which showed through.

The radular spinules were very obviosuly conspicuous and form "well-defined inwardly directed bands" as described in the key. The surface spinules basal to these are very indistinct and hard to see but they are present and only at the centres of the cells, the cells having wide spinule-free margins, so I think that is consistent with the key too.

The forewing length was about 3.1mm so within range for female rhamnicola, and the appearance of the proctiger matches the diagram in the key. The genal cones are perhaps not quite such a precise match for the diagrams in the key, but the description allows for some variation so I think these are ok too.

female Cacopsylla rhamnicola showing genal cones, terminalia and wings (with close-ups showing forewing radular spinules and centre of forewings), Langmere (Norfolk, UK), 7th February 2024