THE WATER-MITES (HYDRACARINA) 86 1 



10 (n) Lateral eyes of each side separate and not enclosed in a capsule. 



Subfamily DIPLODONTINAE. 

 One genus only Diplodontus Duges 1834. 



A large, brownish-red mite with 

 body broad, soft, and surface papil- 

 lated; capitulum forming a snout; 

 palpi very small; legs slender, with 

 long swimming-hairs. One cosmo- 

 politan species, generally distributed 

 in this country and abundant. About 

 2 mm. long. 



FIG. 1325. Diplodontus despiciens (Mul- 

 ler). Ventral surface, male. X 15. Outer 

 side, palpus. X 103. (Modified from 

 Piersig.) 



ii (10) Lateral eyes of each side fused and contained in a chitinous capsule. 



Subfamily HYDRYPHANTINAE. . 12 



12 (17) Without swimming-hairs 13 



13 (14) Median eye present Thyas Koch 1837. 



A genus of red mites of moderate size 

 with papillated surface often with chitinous 

 plates; with capitulum forming a snout; legs 

 with only short spines; a bottom and shore 

 form in swampy situations. Varying in size 

 from i to 2 or even 2.5 mm. Few species 

 known from the Northern States and Canada 

 and not common. 



FIG. 1326. Thyasvenusta Koch, a European, 

 species. Ventral surface female. X 16. Outer 

 side, left palpus. X6$. (Modified from Piersig.) 



14 (13) Median eye not present 



