28 ARKIV FÖR ZOOLOGI. BAND 2. N:0 8. 



Tar SUS of the first i)air oj walking legs seven-jointed , from 



about four to seven times longer than metatarsus. 

 Coxse of the second pair of walking legs without vestige of 



any process at the distal inner (anterior) angle. 

 Metatarsus of the three posterior pairs of walking legs very 



short, several times shorter than tibia and conspicuonsly 



shorter than the first tarsal joint. 

 Two pairs of »lungs», helongmg to second and third ahdoyninal 



segme7its; the spirades not visible without manipulation. 



The trunh of eacli »lung» short ivith the lower wall excee- 



dingly short; the margins of the tracheal »pouches» rather 



firmly chitinized, brown. 



B. Tartarides Cambr. 



Cephalothorax ori the dorsal side divided into a head and two 

 free thoracic segments separated hy memhrane; the firm por- 

 tion of the first thoracic tergite C07isists of two small, short, 

 triangulär, transverse plates rather distant from each other. 



Front eyes wanting; at most one pair of real lateral eyes, gene- 

 rally only a pair of yellowish spöts ivith their surface reti- 

 cidated as the surrounding chitine, or sometimes no vestige 

 of eyes. 



The large cephalic sternum with its lateral angles not pro- 

 duced, reaching only to the inner margin of the coxae of 

 the second pair of walking legs ; its anterior margin straight 

 or feebly convex at the middle, and rounded laterally. 



First abdominal sternite rather feebly chitinized; fourth ster- 

 nite at least at the lateral margins several times longer 

 than the third and but slightly shorter than the fifth. 



Flagellum short; in the female suhcylindrical and divided into 

 three or four, scarcely moi^ahle joints, in the male thickened 

 a^id one-jointed; no yellowish spöts on the lower side. 



First joint of the antennse in^reasing somewhat in depth 

 from the base to the end; the equipment with blood-hairs 

 at the dis tal end and on the »claw» rather scarce. 



Mandibles together at least not shorter than broad; their 

 ventral junction along the mesial line occupies about 

 half of the length from their base to the end of the 

 manducatory lobe. 



