Fig. 313.—Chrysopa flava. Cambridge.
Fig. 314.—Eggs of Chrysopa. A, Five eggs on a leaf; B, one egg, more magnified. (After Schneider.)
Fig. 315.—Larva of Chrysopa sp. Cambridge. A, The Insect magnified; B, foot more magnified; C, terminal apparatus of the claws, highly magnified.
The lacewing-flies—also called stink-flies and golden-eyes—are excessively delicate Insects, of which we possess about 15 species in Britain. Their antennae are more slender and less distinctly jointed than they are in Hemerobiides, and the Chrysopides are more elongate Insects. The peculiar metallic colour of their eyes is frequently very conspicuous, the eyes looking, indeed, as if they were composed of shining metal; this fades very much after death. Although not very frequently noticed, the Chrysopides are really common Insects, and are of considerable importance owing to their keeping "greenfly" in check.
Fig. 316.—Chrysopa (Hypochrysa) pallida, larva. (After Brauer.)
The eggs are very remarkable objects (Fig. 314), each one being supported at the top of a stalk many times as long as itself; in some species (C. aspersa) the eggs are laid in groups, those of each group being supported on a common stalk. The larvae (Fig. 315) are of a very voracious disposition, and destroy large quantities of plant-lice by piercing them with sucking-spears, the bodies of the victims being afterwards quickly exhausted of their contents by the action of the apparatus connected with the spears. The larvae of two or three species of Chrysopa cover themselves with the skins of their victims after the manner of the larvae of Hemerobius; but most of the larvae of Chrysopa are unclothed, and hunt their victims after the fashion of the larvae of Coccinellidae, to which these Chrysopa larvae bear a considerable general resemblance. These larvae have a remarkable structure at the extremity of their feet, but its use is quite unknown (Fig. 315, B, C). Some larvae of the genus make use of various substances as a means of disguise or protection. Dewitz noticed[[399]] that some specimens he denuded of their clothing and placed in a glass, seized small pieces of paper with their mandibles and, bending the head, placed the morsels on their backs; here the pieces remained in consequence of the existence of hooked hairs on the skin. Green algae or cryptogams are much used for clothing, and Dewitz supposes that the Insect spins them together with webs to facilitate their retention. According to Constant and Lucas[[400]] the larvae of Chrysopa attack and kill the larvae of Lepidoptera and Phytophagous Hymenoptera. The curious form we figure (Fig. 316) has been hatched from eggs found by Brauer on Pinus abies in Austria. The eggs were of the stalked kind we have described; the young escaped from them in the autumn, twelve days after deposition, but did not take any food till the following spring.
The Chrysopides are widely distributed over the earth's surface. They form an important part of the fauna of the Hawaiian islands.