402 ZOOLOGY. 



insect* by the structure of their wings, four in 

 number; these are all membranbus, transparent, of ex- 

 treme delicacy, and of equal utility for flight. The body of 

 such insects is generally soft, and very elongated. Finally, 

 some undergo a complete metamorphosis, others only a semi- 

 metamorphosis. This order comprises the libellulae (Fig. 387), 

 the agrions (Fig. 148), the ephemera (Fig. 376), the fourmi- 

 lion (Fig. 97), the friganidse, the termites, &c. 



Fig. 386.-Phjllie Peuille Seche (Phyllium Succifolium). 



These last insects, known also by the name of white ants. 

 are very destructive; they are met with chiefly in warm 

 countries, but they cause considerable detraction in some 

 parts of France, as at Rochelle and at Rochefort, lor example : 

 they destroy the timber of carpenters' work, and live in 



