THE WATER-MITES (HYDRACARINA) 



86l 



to (ii) 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 despkiens (M-iii- 

 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 ted 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. 



Ftg. 1326. Thyas venusla Koch, a European 

 species. Ventral surface, female. X 16. Outer 

 side, left palpus. X 65. (Modified from Piersig.) 



14 (13) Median eye not present 



IS 



