Green lacewings

Green lacewings are delicate insects with a wingspan of 6 to over 65 mm, though the largest forms are tropical. They are characterized by a wide costal field in their wing venation, which includes the cross-veins. The bodies are usually bright green to greenish-brown, and the compound eyes are conspicuously golden in many species. The wings are usually translucent with a slight iridescence; some have green wing veins or a cloudy brownish wing pattern. The vernacular name "stinkflies", used chiefly for Chrysopa species but also for others (e.g. Cunctochrysa) refers to their ability to release a vile smell from paired prothoracal glands when handled.

Adults have tympanal organs at the forewings' base, enabling them to hear well. Some Chrysopa show evasive behavior when they hear a bat's ultrasound calls: when in flight, they close their wings (making their echolocational signature smaller) and drop down to the ground. Green lacewings also use substrate or body vibrations as a form of communication between themselves, especially during courtship. Species which are nearly identical morphologically may sometimes be separated more easily based on their mating signals. For example the southern European Chrysoperla mediterranea looks almost identical to its northern relative C. carnea (Common Green Lacewing), but their courtship "songs" are very different; individuals of one species will not react to the other's vibrations.
Larva of unknown species (from Latvia) camouflaged with sand grains

Adults are crepuscular or nocturnal. They feed on pollen, nectar and honeydew supplemented with mites, aphids and other small arthropods, and some, namely Chrysopa, are mainly predatory. Others feed almost exclusively on nectar and similar substances, and have symbiotic yeasts in their digestive tract to help break down the food into nutrients.

Larvae have either a more slender "humpbacked" shape with a prominent bulge on the thorax, or are plumper, with long bristles jutting out from the sides. These bristles will collect debris and food remains – the empty integuments of aphids, most notably – that provide camouflage from birds.