ARTHROPODS. CLASS iHSECTS 



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thin and membranous wings incapable of being folded. 

 These possess a network of delicate nervures, giving the 

 general name nerve- winged insects to these various small, 

 orders. Of the forms mentioned above, all but the white 

 ants lay their eggs in the water, and the developing larvae 



FIG. 77. Dragon-fly (Libdlula pulchefla"). 



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, a type of the related order (Neuroptera), which 

 has somewhat the appearance of a small dragon-fly, lays its 

 eggs in light sandy soil. In this the resulting larvae exca- 

 vate funnel-shaped pits, at the bottom of which they lie con- 



