Fig. 310.—A, Larva of Sisyra fuscata, ventral aspect; B, an abdominal appendage. (After Westwood.)
Fig. 311.—Larva of Hemerobius sp. from Kent. A, The larva bare; B, the same, partially concealed by the remains of its victims, etc.; a portion of the covering has been removed in order to show the head.
4. Hemerobiina: a somewhat numerous group of small or more rarely moderate-sized Insects, with moniliform antennae, no ocelli, a complex and comparatively regular system of wing-nervures; the veinlets are especially numerous at the margins, owing to the mode of forking of the nervures there (Fig. 298, Drepanepteryx phalaenoides). The larvae of most of the species of which the habits are known live on Aphides, which they suck dry, and at least one species, in all probability several, has the habit of covering itself with the skins of the victims it has sucked; to these remains it adds other small debris, and the whole mass completely covers and conceals the Insect (Fig. 311, B). The larva is furnished at the sides with projections which serve as pedicels to elongate divergent hairs, and these help to keep the mass in place on the back of the Insect; some fine threads are distributed through this curious mantle and serve to keep it from disintegration, but whether they are fragments of spiders' webs or are spun by the Insect itself is not quite clear.
Fig. 312.—Portions of wings of Drepanepteryx phalaenoides. A, Under-face of basal parts of the two wings; a, base of front wing; b, of hind wing. B, Portion of front wing, showing the apparent interruption of nervures.
The genus Drepanepteryx consists of several species, and appears to be best represented in the Antipodes; we have, however, one species in Britain—D. phalaenoides (Fig. 298)—an extremely interesting member of our fauna. This Insect has, like several of its congeners, a moth-like appearance, and it has a peculiar structure for bringing the hind and fore wings into correlation, the costa at the base of the hind wing being interrupted and prominent, furnished with setae (Fig. 312, A), and playing in a cavity on the under-surface of the front wing. This character is of great interest in connexion with analogous structures of a more perfect nature existing in various moths. M‘Lachlan has described and figured[[398]] a more primitive, though analogous, condition of the wings in Megalomus hirtus, also a species of British Hemerobiina. Another very curious feature of D. phalaenoides is shown in Fig. 312, B, there being a narrow space on the hind part of the front wing from which the colour is absent, while the nervures appear to be interrupted; they are, however, really present, though transparent; the nature of this peculiar mark is quite unknown, but is of considerable interest in connexion with the small transparent spaces that exist on the wings of some butterflies.
Sub-Fam. 6. Chrysopides, Lacewing-flies.—Fragile Insects with elongate, setaceous antennae.
