THE WATER-MITES (HYDRACARINA) 

 38 (37) Genital area with numerous ace tabula on each side. 



867 

 Albia Thon 1899. 



A mite of medium size, averaging 

 about i mm. in length, with elliptical, 

 strongly compressed body; swimming- 

 hairs present. One North American 

 species, rather rare, in lakes of northern 

 states, frequently pale greenish in color. 

 This is identical with the only Euro- 

 pean species, A. stationis Thon, or 

 very closely related. 



FIG. 1339. Albia stationis Thon. Ven- 

 tral surface, female. X 31. Outer side, 

 palpus, female. (After Thon.) 



39 (24) Body highly arched, in some cases laterally compressed, with no such 

 dorsal and ventral plate. Subfamily LEBERTIINAE. . 40 



Legs with swimming-hairs except in certain species of Lebertia. 



40 (41) Leg IV with claws at tip, epimera only partly fused. 



Lebertia Neuman 1880. 



Medium-sized mites, varying in length from 

 0.8 to 1.5 mm., with ovoidal body, the surface 

 of which is soft or hard, in some cases with 

 small flecks of chitin, usually striate, but rarely 

 papillate; capitulum developed more or less into 

 a short snout. A genus of frequent occurrence 

 in colder waters, represented by several closely 

 allied species which have only been recently 

 recognized as distinct. 



FIG. 1340. Lebertia tau-insignita (Lebert), of various 

 authors, L. dubia Thon. This species was referred to 

 North America by Koe'nike in 1895, but he has re- 

 cently identified three species in the material he 

 studied, all of them hitherto undescribed. Ventral 

 surface of female. X 19. Outer side, palpus, 

 female. X 70. (Modified from Piersig.) 



41 (40) Leg IV without claws at the tip, ending in a sharp point, epimera 

 completely fused 42 



