ARTHROPODS. CLASS INSECTS 



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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 larvae 



FIG. 71. Dragou-fly (LibeUula pulchella). 



spend their lives in this medium until the time comes for their 

 complete metamorphosis into the adult. The larvae 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 larvae excavate funnel-shaped pits, at the bottom 

 of which they lie concealed. Insects stumbling into their 

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