Wesmaelius concinnus

This species had not been recorded coming to light in Norfolk before I took this one. The last county records before this were one found in a Malaise trap in 1983 and one beaten from pine in 1994.

Like Hemerobius, Wesmaelius has a recurrent humeral vein but unlike Hemerobius the cross vein RMCV falls distal to the fork in vein M. Separating the various species of Wesmaelius from one another usually requires examination of the tip of the abdomen. This is hard to do on live specimens so it will normally be necessary to retain specimens for identification.

The shape of the appendage at the tip of the abdomen is crucial for identifying males. On females you need to look at the genital plate which is best viewed by clearing the abdomen in, for example, potassium hydroxide solution.

This was noticeably large and broad-winged for a brown lacewing - the largest I've seen (10.3 mm forewing) - and quite different in appearance compared to the two commoner Wesmaelius species in Norfolk (nervosus and subnebulosus).

female Wesmaelius concinnus showing fore and hindwings, abdomen from side and below including close-ups of genital plate, North Elmham (Norfolk, UK), 12th July 2022