WATER-MITES AND THE WATER-BEAR. 269 



2. DlPLODONTUS. 



This mite may be recognized by the form of the ven- 

 tral plate as given in the Key, and by the fact that the 

 plate is roughened by minute granules. The eyes in 

 one species are two in number, very small, and wide 

 apart. They are placed on the edge of the front border. 

 In another species they are four, and are placed so far 

 forward on the front margin that they are best' seen 

 when the animal is on its back, and thus examined from 

 beneath. The coxae are in four separate groups. The 

 body of the two-eyed species has the front part black, 

 spotted with red, and the posterior half red, with a central 

 longitudinal black band. The one with four eyes has the 

 body bright red. 



3. HYDRACHNA (Fig. 173). 



The anterior coxae on the same side form a single 

 group, being in contact by their whole length; the mid- 

 dle one is entirely disconnected from the 

 others ; the most posterior is the largest, 

 and is also entirely separate. In one 

 species the body is spherical and black, 

 with yellow dots, the legs being shorter Fig. ITS. coxse of 

 than the body, and black, with red ends. 

 In another the body is red, with two pairs of dark red 

 eyes, and long legs. The young are said to have but 



three legs. 



4. EYLAIS (Fig. 174). 



The two anterior coxse are in contact by their entire 

 length, and form one group on each side. The two 



