In the British Isles there are three species of Sisyridae all in the genus Sisyra:
Sisyra nigra, Sisyra terminalis, and Sisyra dalii
Occassionally, there can be confusion between the family Hemerobiidae (Brown Lacewings) and Sisyridae, as they superficially resemble each other. If you look at the forewings it is relativley easy to differentiate between these two families. Hemerobiidae only have two longitudinal veins in the the top half of their forewing, whereas Sisyridae have three (see image below).
It is possible to identify these species from good quality photographs, where the wing and antennae are in focus (see below).
However, it is very easy to differentiate between the species by looking at the male genitalia:
