Green lacewing larvae are common predators of several soft-bodied arthropods pests such as scale insects, spider mites, aphids, thrips, and eggs of pest insects. They are useful in biological control because of their generalist and voracious feeding habits.
Lacewing larvae have large pincer mouthparts that they use to penetrate bodies of prey, paralyze them, and suck out their insides. They use these mouthparts to devour several hundred prey per week. Lacewings are known to be cannibalistic if they cannot find any other food source. This is probably one reason they deposit their eggs individually on long hairs that suspend them above the leaf surface out of reach. You can find these eggs very easily just by searching leaves of trees and bushes. They are even more common on plants with lots of prey.
Some but not all green lacewing larvae develop a camouflage cover which hides them from their prey and predators. These are called debris-carrying lacewing larvae because they pick up plant debris, lichen, and remains of their prey and attach it to their back. This camouflage makes them difficult to recognize by prey, natural enemies, and the
inexperienced human eye. Often they will appear to be a cluster of tree lichen until you notice it start to move. This time of year when flatid planthoppers are producing lots of cottony fluff I see lacewings covered in the same cottony fluff. On a hike in Umstead State Park last week I found half a dozen. Debris carrying lacewing larvae are easy to find. Just look for little mounds of debris moving around the top of leaves.
The ones covered in flatid fluff are bright white and stand out against leaves. They remain larvae for two to four weeks then pupate and emerge as winged green lacewing adults. Adult lacewings are not predators and primarily feed on plant nectar. The adults are commonly attracted to lights at night and can often be found around your home.