Nerve-winged Insects; Scorpion-flies; Caddis-flies 229 
half an inch high, fastened at the base to a leaf or twig (Fig. 314). When 
the first larvae hatch they crawl down the stems and wander around in this 
little forest of egg-trees, but fortunately haven’t wit enough to crawl up to 
the still unhatched eggs of their brothers and sisters. When the aphis-lion 
is full-fed and grown, which, in the studied species, occurs in from ten days 
to two weeks, it crawls into some sheltered place, as in a curled leaf or 
crevice in the plant-stem, and spins a small, spherical, glistening, white, 
silken cocoon, within which it pupates. In another ten days or two weeks 
the delicate lace-winged golden-eyed green imago bites its way out, cutting 
out a neat circular piece. 
In the family Hemerobiidse are some insects whose larvae are also called 
aphis-lions; these belong to the typical genus Hemerobius. But in two 
rare genera of the family, Sisyra (Fig. 315) and Climacia, the immature 
stages are aquatic, the small larvae (about J inch long) living as parasites 
Fig. 317. 
Fig. 315c. 
Fig. 315&. 
Fig. 215 .—Sisyra umbrata. a, adult; b, larva; c, pupa. (All about five times natural size.) 
Fig. 316 .—Polystcechotes punctatus. (Natural size.) 
Fig. 317. —Hemerobius sp. (Three times natural size.) 
on or in fresh-water sponges (Spongilla). The largest members of the 
family belong to the genus Polystoechotes, of which two species are known. 
The commoner one, P. punctatus (Fig. 316), is about 1} inches long and its 
wings expand 2 to 3 inches. It is nocturnal and is to be collected about 
