Close-up of head, showing bristles and compound eyes
Neuropterans are soft-bodied insects with relatively few specialised features. They have large lateral compound eyes, and may or may not also have ocelli. Their mouthparts have strong mandibles suitable for chewing, and lack the various adaptations found in most other endopterygote insect groups.
They have four wings, which are usually similar in size and shape, and a generalised pattern of veins. Some neuropterans have specialised sense organs in their wings, or have bristles or other structures to link their wings together during flight.
The larvae are specialised predators, with elongated mandibles adapted for piercing and sucking. The larval body form varies between different families, depending on the nature of their prey. In general, however, they have three pairs of thoracic legs, each ending in two claws. The abdomen often has adhesive discs on the last two segments.
As in other holometabolic orders, the pupal stage generally is enclosed in some form of cocoon composed of silk and soil or other debris. The pupa eventually cuts its way out of the cocoon with its mandibles, and may even move about for a short while before undergoing the moult to the adult form.
Lace wing larva or "trashbug"
Adults of many groups are also predatory, but some do not feed, or consume only nectar.
The use of Neuroptera in biological control of insect pests has been investigated, showing that it is difficult to establish and maintain populations in fields of crops.
Neuroptera have artistic demonstrations since beginning of civilizations, which can be found in numerous art galleries such as Lacewing Design Gallery and Studio of Northampton, Lacewing fine art of Salisbury.
The New Guinea Highland people claim to be able to maintain a muscular build and great stamina despite their low protein intake as a result of eating Neuroptera among other insects.
Taxonomy and systematics
A 49-million-year-old fossil wing of Palaeopsychops marringerae (Polystoechotidae), showing color pattern
The understanding of neuropteran phylogeny has vastly improved since the mid-1990s, not the least courtesy of the ever-growing fossil record. In 1995, for example, it was simply known that the Megaloptera and Raphidioptera were not part of the Neuroptera in the strict sense, and the Mantispoidea and part of the Myrmeleontoidea were the only groups that could be confirmed by cladistic analysis. Though the relationships of some families remain to be fully understood, most major lineages of the Neuropterida can nowadays be robustly placed in an evolutionary context.