408 



ZOOLOGY. 



suction, not consisting in a single proboscis, but with tin 1 

 form of a bill or beak, in the interior of which are sharj. 

 stylets, adapted to perforate animal or vegetable tissues, in 



Fig. 396. Pentomna (Cimex ornatus) . Fig. 397. Halys, or Wood Bug. 



which the animal finds the liquids by which it is nourished 

 ( 523). These insects have generally four wings, like all the 

 preceding, but usually those of the first pair are only mem- 

 branous towards the extremity, and constitute semi-elytra. 

 Finally, the metamorphoses are incomplete, and the insect as 

 it grows changes neither its form nor its habits ; only it in 

 general requires wings, which it had not at first ; sometimes 

 however they remain without these organs. This is the 



Fig. 398. The Balm Cricket. 



case with the bed bugs, for example. We arrange in this 

 order the pentatoma, the halys or wood bug (Fig. 396 and 

 397,) &c., the nepas or water flea (Fig. 400), the cigale or 



