Lacewings are common insects in British gardens and are easy to recognise by their transparent lace-like wings, which are nearly twice as long as the abdomen. Lacewing larvae are voracious consumers of aphids and insect eggs. There are several British lacewing species, which are often divided by colour, into green (14 species) or brown (29 species) forms. The giant lacewing (Osymlus fulvicephalus), with a wingspan of up to 5 cm, is often found near streams and rivers. They are fairly slow moving and would make a ready meal for a foraging bird, so are rarely seen flying during the day. Instead of feeding on aphids, the larvae of the giant lacewing are semi-aquatic, and feed on the larvae of midges and other small species. Lacewings can be encouraged to remain in your garden by providing homes for their winter hibernation, which can be bought from some garden centres. They will be ready to lay eggs and help to control your aphids when they emerge from hibernation in the spring.
Lacewings court by 'tremulation', a low frequency sound produced by vibrating their abdomens, which in turn causes the substrate they are standing on to vibrate. The males and females will take turns tremulating; this duet is an essential prerequisite for mating.
The common green lacewing was thought to be one species, but recent research has shown that they are several closely-related species, which can only be distinguished by their courtship songs.