330 



ARTICULATA: IJSTSECTA. 



Bark-lice or Coccidse are very small hemiptera which 

 are found in the form of scales on the bark of trees. The 

 males alone are winged ; the females are always in the 

 scale-like form. The Bark-lice are famous for 'the dyes 

 and other useful materials which they have furnished. 

 The cochineal of Mexico, and the scarlet grain of 

 Poland, are insects of this family; and species of 



FIG. 442. 



FIG. 443. 



Bark-louse, Aspidiotus Harrisii, Walsh. A and B enlarged. 



Bark-lice furnished the famous Icokkos of the Greeks, the 

 coccus of the Komans, the kermes of the Arabs, the cocchi 

 of the Italians, and the alkermes of the Persians. 



Some kinds of hemiptera, as the Boat-flies or Notonec- 

 tidse, live in the water, and are noted for 

 their habit of swimming on their backs. 

 Others, as the Scorpion-bugs or Nepidse, 

 live in the water, and are adapted for 

 seizing prey by their fore legs, which 

 flex upon themselves, and thus act as 

 pincers. Some kinds of scorpion-bugs 

 (Fig. 443) are no more than an inch long ; 

 but some species of Belostoma, with an 

 oval body, attain a length of three or four 

 inches, and J?anatra, with a narrow body, 

 is about three inches in length. Other 

 kinds of hemiptera, as the water-measurers or Hydrometri- 

 dre, are found on the surface of water, over the surface oi 

 which they move with a gliding motion. 



To the Hemiptera belong the little Chinch-bug 



Scorpion-Bug, 

 apinilata, 

 Harris. 



