THE PSOCIDH 
351 
and carried to a part of the ant hill, where they are hatched and 
the larvae are attended to and nursed until they are able to shift 
for themselves. The engraving on the opposite page shows a full- 
sized queen. The metamorphosis is very incomplete, and the larvae 
resemble the adults except in not having full-grown wings, but 
there are other arrests of development, and the limitation of the 
power of reproduction is very definite. The pupae hardly differ 
from the larvae and the adult forms. 
There are some small Neuroptera which resemble the Termes 
somewhat, but their habits are comparatively uninteresting. They 
are the Psocidce. They have wings which are slightly veined, large 
heads, with three ocelli on the forehead, setiform antennae, and 
very slender legs. These insects are found on mosses and upon 
the trunks of trees and old walls, and a very small species inhabits 
houses, and is particularly fond of crawling amongst old and 
damp papers. The wings of the females never become developed, 
and they therefore remain, as it were, in a larval condition. It 
looks something like a little louse, and as it is said to make a 
noise by clashing its jaws together, it has been called Psocus 
pulsatorius. 
The Perlidce are very distinct as a family. They are mode- 
rately-sized Neuroptera, with large hind wings, which are folded 
near their attachment. They have setiform or thread-shaped 
antennae and well-developed jaws. Moreover, they present mani- 
fest resemblances to the Orthoptera , as do the Termites and the 
Psocidce. Pictet of Geneva has paid great attention to the Euro- 
pean species of this family. The Perlidce undergo incomplete 
metamorphoses. The larvae are aquatic, carnivorous, active, and 
are often provided with external respiratory organs or gills, which 
consist of small tufts of filaments that are attached to the lower 
part of the segments of the thorax. The nymphs or pupae, which 
are always active, differ from the larvae in having the rudiments 
of wings. 
When the nymphs have attained their full size they leave the 
water and settle upon the stones or plants on the bank ; their 
skin soon dries and splits along the back, and then the adult or 
perfect insect scrambles out and takes to flight. The larvae 
appear to prefer running streams, and they pass the winter at 
