98 



BUCCAL APPARATUS OF INSECTS. 



able to pierce the skin of animals or the vessels of plants, are 



the representatives of the 

 mandibles and the maxilla) 

 extremely elongated. In those 

 Ui/ nir Hemiptera which live at the 



expense of other animals, the 

 proboscis is usually very firm, 

 and folds into a semicircle 

 under the head. Among those 

 which are nourished by suck- 

 ing vegetables, on the con- 

 trary, it is nearly always thin, 

 and is laid when in a state of 

 rest against the lower side of 

 the thorax, between the feet. 

 Its length is sometimes so 

 considerable, that it passes backwards behind the posterior ex- 

 tremity of the abdomen. 



616. Amongst the Flies, also, the proboscis, which is some- 

 times soft and retractile, sometimes hprny and lengthened, repre- 

 sents the under lip, and often bears palpi at its base ; a longi- 

 tudinal channel occupies its upper side, which incloses the setce ; 



FIG. 320. BUCCAL APPARATUS OF AN 

 HEMIPTEROUS INSECT. 



FIG. 321 NEMESTRINA LONGIROSTRIS. 



whose number varies from two to six, their analogues amongst 

 the gnawing insects being the mandibles, the maxillae, and the 



