Sympherobius fuscescens

Sympherobius fuscescens

Four of the five British Sympherobius species have been found in Norfolk so far but none of them have been recorded more than half a dozen times up to 2025. However, as I've recorded 11 individuals covering all four species in unremarkable habitat here in North Elmham, I think they must be vastly under-recorded.

Most members of the genus tend to be rather dark brown and thus can recall the spongeflies (family Sisyridae). They can be distinguished from spongeflies by the presence of a recurrent humeral vein and the presence of forks in many of the veins along the front margin of the wing. From other genera of brown lacewings they are best differentiated by having fewer cross-veins in the hindwing (specifically, according to Plant (1997), none in the outer third of the hind wing OR no more than four altogether) - of course this is very hard to see on a live insect and unlikely to be evident from photos.

Like Sympherobius pellucidus and Sympherobius klapaleki, but unlike the other species in the genus, fuscescens has three branches to the radial sector of the forewing - the others have two. Unlike pellucidus, there is no distinct darkening around the cross-veins of the forewing, however this needs to be judged carefully: in my experience this darkening was not obvious on pellucidus though it was apparent in photos of the live insect, whereas on fuscescens a tiny amount of darkening is apparent if you look very closely, but this was not apparent in photos of the live insect. Sympherobius klapaleki is similar to Sympherobius pellucidus but has contrastingly pale yellow-brown first and second segments of the antennae. Identification of males is best confirmed by examining the tip of the abdomen (again, see Plant for diagrams).

Although historically Sympherobius fuscescens was the best-recorded Sympherobius in Norfolk (with four records) none were reported after 1994 until I caught three in two nights in my garden moth trap in 2025. Unfortunately all three were females - I would really like to find a male!

female Sympherobius fuscescens showing right forewing and hindwing and close-up of right forewing, North Elmham (Norfolk, UK), 12th July 2025