Sarcoptiformes 339 



Hyadesidae Halbert, 1915 



Figures 265, 266 



Diagnosis: Strongly arched dorsally the body of these mites is plump. 

 The propodosoma and hysterosoma are separated by a suture. A pair 

 of vertical setae are present and a delicate propodosomal shield may 

 also be present. The skin is otherwise soft, with very fine striae. The 

 chelicerae are normal. Tarsi i and ii in both sexes are in shape of a 

 large claw, with an accessory claw on the inside; the extremely long 



Figure 265 Hyadesia algivo- Figure 266 Left, leg i of Hyadesia algivorans 



rans (Michael). Dorsal view (Michael). (After Michael 1901); right, leg i 



of female. (After Michael of //yaa'e^/fl ///.?cfl Lohman. (After Andre 1931) 

 1901) 



Stalk of the small caruncle, which carries distally the very small, true 

 claw, is attached at the base of the accessory claw. Tarsi iii and iv of 

 the female have one large claw on a short stalk; in the male the large 

 claw sits on a longer stalk. There is slight sexual dimorphism. Both 

 male and female genital openings are at a considerable distance be- 

 hind coxae IV. There are no genital suckers nor does the male have 

 adanal copulatory suckers. 



Genus: 



Hyadesia Megnin, 1889 (= Lentungula Michael, 1893) 

 Type. Hyadesia uncinifer Megnin, 1889 



Discussion: These mites are found in the tidal zone, on sea algae. 

 Michael 1901 reports finding large numbers of Hyadesia algivorans 



