ARTHROPODS. CLASS INSECTS 119 
possess four thin and membranous wings incapable of being 
folded. These possess a network of delicate nervures, giv- 
ing the name Neuroptera (meaning nerve-winged) to the 
class. Of the forms mentioned above, all but the white 
ants lay their eggs in the water, and the developing larve 
Fig. 71.—Dragon-fly (Libellula pulchella). 
spend their lives in this medium until the time comes for their 
complete metamorphosis into the adult. The larve of the 
caddis-flies protect themselves within a tube of stones or sticks 
bound together with silken threads, which they usually 
attach to the under side of stones in running water. On 
the other hand, the young of the dragon- and may-flies, pro- 
vided with strong jaws, are active in the search of food and 
very voracious. In time they emerge from their larval skin 
and the water in which they live, and after a life spent on 
the wing they deposit their eggs and perish. The adult 
ant-lion, which has somewhat the appearance of a small 
dragon-fly, lays its eggs in light sandy soil. In this the 
resulting larve excavate funnel-shaped pits, at the bottom 
of which they lie concealed. Insects stumbling into their 
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