336 THE MICROSCOPE. 



other reptiles. The animal known as the Harvest-bug, which is often 

 so troublesome in summer and autumn, also belongs to this group. 

 The Gamaside, which are furnished with a sucking apparatus very 

 similar to that of the Ixodidce, usually attach themselves to the bodies 

 of beetles ; the common Dung-beetles (Geotroupes) may often be found 

 with the lower surface nearly covered with them. 



The remainder generally lead a more active life, and are always 

 furnished with eyes. One family, the Hydrachnidce, or Water-mites, 

 inhabit the water, where they swim about with considerable rapidity 

 by means of their fringed legs. In their young state, they attach 

 themselves parasitically to aquatic insects ; they then possess only six 

 legs, and pass through a quiescent or pupa state before acquiring the 



fig. 165. The Sheep-tick. The small circle shows one of life size. 



fourth pair. The Oribatidce which, unlike the other Acarina, live 

 upon vegetable matter, principally the leaves of mosses, are covered 

 with a hard and very brittle skin, and have the mouth adapted for 

 biting. The Bdellidce, which live amongst damp moss, have the body 

 divided apparently into two parts by a constriction, and the rostrum 

 and palpi very long ; whilst the Trombidiidce, of which the little Scarlet 

 Mite so often seen in gardens is an example, have the palpi converted 

 into little raptorial organs. 



