Order Neuroptera - Lacewings, Alder Flies & Snake Flies

• Ant-lion
• Lacewing
• Snake Fly
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Small to large soft-bodied insects, with two pairs of very similar membranous wings covered with a delicate network of veins and held roof-wise over the body at rest. Antennae generally long and thread-like, sometimes with a terminal club. Mouthparts for biting. Abdomen fairly slender, without cerci. There is a complex metamorphosis, with a pupal stage. The larvae are carnivorous, with biting or suctorial mouthparts. This is an ancient Order and contains some of the most primitive living endopterygote insects. Nearly 5,000 species are known, of which about 60 occur in the British Isles.

There are considerable differences, particularly in the young stages, between the Alder Flies and Snake Flies on the one hand and the rest of the Neuroptera on the other. In fact, many entomologists place the insects in two separate Orders. When treated as a single order, the Alder Flies and Snake Flies (whose larval stages have biting mouthparts) are placed in a sub-order called MEGALOPTERA, and the rest of the Neuroptera (Ant-lions, Lacewings, etc., whose larvae have sucking mouthparts) are placed in a sub-order called PLANIPENNIA.

Description. Adult 35-40 mm long, superficially like a dragonfly, but easily distinguished by its stout, clubbed antennae and much slower flight. Wings with brown spots. Larva greyish-brown, up to 12 mm long, with large powerful jaws curving inwards at the tips and a broad oval body.

Biology. Found in sandy places, often on the edges of coniferous forests. The adults fly with a lazy rising and falling motion and rarely move far at any one time. The name 'Ant-lion' refers to the larva. This lives in sandy soil and excavates a small pit. It buries itself at the bottom, leaving only its strong jaws above the sand. When passing insects fall into the pit they slip to the bottom on the loose sand and are quickly seized by the ant-lion and sucked dry. The pits of full-grown larvae are up to 5 cm deep and 8 cm across. Larvae take two years to complete their development.

Distribution. Europe.

Photos: V.J. Stanek ©

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Adult

Larva

Larval pits

Description. Adult about 15 mm long, with the body and wing veins a delicate shade of green. The prominent eyes have a bright metallic appearance. Larvae up to 12 mm long, mottled brown, with long curved jaws.

Biology. Both adults and larvae are important natural enemies of aphids (greenfly, blackfly, etc.) and can provide a biological control of these plant pests.

Distribution. Europe, including the British Isles (similar species occur in parts of Africa, Asia and North America).

Photo: A. Feininger ©

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Description. Adult about 10-12 mm long and dark brown in colour. Easily recognised by the long thorax, which can raise the head above the rest of the body in the manner of a snake about to strike. The female has a long, tail-like ovipositor at the end of the abdomen. The larva is also brown, with a slender, elongated body, narrow thorax and short, but strong, biting jaws.

Biology. Generally found on trees, especially in oak woodland. The female uses her long ovipositor to lay eggs deep in the cracks and crevices of tree bark. The larvae live mainly under loose bark, where they feed on other insects. They can be important predators of insect pests, such as aphids, scale insects and bark beetle larvae.

Distribution. British Isles and parts of Europe.

Photo: V.J. Stanek ©

Adult Male