Nerve^winged or Lace^winged Insects 



701 



plants. In colour it is pale green, with a peculiar milky appearance, and the eyes glow as 

 though lighted by an inward fire. The wings are so closely and elaborately veined that 

 they look like a piece of the most delicate lace-work. It is not advisable to handle the insect, 

 for, although perfectly harmless, it possesses the power of pouring out from its body a liquid 

 of the most horrible odour, which clings to the fingers in spite of repeated ablutions. 



The life-history of the lacewing-fly is very curious. When the maternal insect lays her 

 eggs, she first deposits a drop of a highly glutinous fluid upon a leaf or slender twig, and 

 then, with an upward jerk of her long body, draws it out into a slender thread. On contact 

 with the air this thread immediately hardens, and just as she releases her hold the fly attaches 

 a single egg to the tip. In this way 200 or 300 eggs are laid together in a little cluster, 

 which looks just like a tiny patch of moss. In the earlier botanical manuals, indeed, it was 

 actually named, figured, and described as a moss. 



The grubs which hatch out from these eggs feed upon plant-lice, of which they devour 

 vast numbers, draining the juices by means of their 

 hollow jaws, and then fastening the empty skins on 

 their own backs, as an American Indian might decorate 

 himself with the scalps of his victims. Owing to this 

 singular habit, the grub becomes perfectly unrecognis- 

 able after the first few days of its life, only the jaws and 

 feet being visible beneath the pile of dry skins. When 

 fully fed, it changes to the pupal condition in a silken 

 cocoon, which it attaches to a leaf, and the perfect insect 

 makes its appearance in the course of a few days. 



The ALDER-FLIES, in general appearance, are not 

 unlike caddis-flies, but may easily be distinguished by the 

 fact that the wings are not longitudinally folded while at 

 rest. They are very abundant in the neighbourhood of 

 ponds and small streams, where they may be seen flying 

 slowly and heavily, or resting on low herbage or the foliage 

 of trees and bushes. The female insect lays her eggs in 

 clusters of 300 or 400 on the leaves of water-plants, 

 and the little grubs make their way down into the water 

 immediately on hatching out, where they creep about on 

 the mud at the bottom in search of the tiny creatures on 

 which they feed. When full-grown, they are about an 

 inch in length. They then leave the water and bury 

 themselves in the earth, where they change to pupae, 

 the perfect insects emerging in June or July. 



The CADDIS-FLIES, of which there are many British representatives, belong to the Hairy- 

 winged group. The larvae of these insects are entirely aquatic, and remind one of hermit-crabs, 

 the front part of the body being clothed with horny armour, while the hinder part is entirely 

 unprotected. In order to escape the attacks of predaceous insects these grubs construct cases 

 round their bodies, which they drag about wherever they go. In one or two instances, 

 however, the case is attached to the lower surface of a stone. 



The materials of which these cases are made vary in accordance with the species. In one 

 group, for instance, they consist of pieces of twigs and leaves, cut into short lengths, and arranged 

 side by side in such a manner as to form a spiral band. The larva of another kind uses entire 

 leaves, gluing them firmly together and living between them. A third species employs grains of 

 sand and tiny stones, which it arranges in the form of a cow's horn. Most curious of all, however, 

 is the case of a caddis-fly which is made entirely of the shells of water-snails. As these shells are, 

 as a rule, still tenanted by their owners, the snails may sometimes be seen attempting to crawl 

 simultaneously in half a dozen different directions, while the grub is dragging them in a seventh. 



Photo by W. P. Dando, F.Z.S., Regent's Park. 

 LARGE CADDIS-FLY. 



The largest British species measures about an inch and a' 

 half across the wings. 



