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NEUROPTERA. 
Perhaps the commonest instance of truly gregarious insects are the 
free-living Psocidce which live under a common web in little colonies on 
the leaves and bark of trees and other plants. Possibly the common 
link is the shelter that the web provides, possibly there is some faint 
approximation to the truly social condition. Another instance are the 
Emhiidce. One finds numbers of these delicate insects together using 
the same silken runs and living in a little colony together. It is doubt¬ 
ful if they ever live in any other way but why they should do so is not 
clear ; the reason that suggests itself is that there are few spots suitable 
to them and that here they naturally gather and make common runs 
and shelters. A better and more striking instance is the Pyrrhocorid 
bug Iphita limbata ; great numbers of this bug cluster together on one 
spot on a tree trunk, and that they remain there is shown by the heap 
of exuviae below the spot. Why they do so is not at all clear ; their ally 
the Red Cotton Bug ( Dysdercus cingulatus) appears to have the same 
habit, but this is clearly a case of food or of enhancing their warning 
eolour and they cluster on the seeds or pods to feed or sleep only. The 
Coreid Corizus rubicundus, Westd., lives till mature in clusters which look 
like vivid red flowers. Some moth caterpillars and a few Pierid cater¬ 
pillars are gregarious, hatching from eggs laid in clusters and remaining 
together for a longer or shorter time. Some remain in webbed leaves 
till they pupate ; others for a short time only and in these cases, which 
are fairly numerous, the web made as a shelter is often the reason. Thus 
Caradrina exigua larvae remain together for a few days in the webbed 
leaves as do the larvae of Diacrisia obliqua and many other Noctuids and 
Arctiids. An interesting gregarious insect is the common MacJiilis found 
on rocks and under leaves ; it is apparently always gregarious. Young 
Pentatomids are often gregarious for the first two or three instars, and the 
persistent way in which some remain together when newly hatched out 
shows that it is instinctive. Cockroaches are gregarious also and 
apparently often prefer being in company to being alone. Gyrinidce are 
distinctly and markedly gregarious and apparently take delight in their 
combined evolutions on the surface of still water. Opatrum among 
Tenebrionids is gregarious in the sense that the beetles like to crowd 
together in groups and clusters instead of remaining solitary. Haltica 
cyanea, Web., is another beetle that lives and feeds in company, 
though such instances are very rare. 
Perlidje. —Stone flies. 
Delicate insects , with the hind wings large and folded beneath the 
forewings. Legs widely separated , with small coxce. 
Larva aquatic. 
These typically Neuropterous insects are distinguished from other 
allied groups by the above characters, by the long antennae, and the 
