CHAPTER IX. 



Order CORRODENTIA (Cor-ro-den'ti-a). 



The Psocids (Psocids) arid the Book-lice. 



The vvinged members of this order have four membranous 

 wings, with the veins prominent ', but with comparatively few 

 cress veins; the fore wings are larger than the hind wings; 

 and both pairs when not in use are placed roof -like over the 

 body, being almost vertical, and not folded in plaits. The 

 month-parts are formed for biting. The metamorphosis is in- 

 complete. 



The name of this order is from 

 the Latin corrodere, to gnaw, and 

 refers to the gnawing habits of these 

 insects. 



The wings, especially the fore 

 wings, are often smoky in color or 

 F.G. ^j.-fiacus venous. variegated. The arrangement of the 



veins of the wings (Fig. 107) differs in a striking manner 

 from that of any other biting insect. 



The order includes two families, but representatives of 

 only one of them occur in the United States. 



Family PSOCIDS (Psoc'i-dae). 

 The Psocids (Pso'cids) and the Book-lice. 



Books may be old and out of date from our standpoint, 

 but still be of vital importance to others. Take down from 

 the shelf a time-yellowed book and open its neglected leaves 



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