NORTH AMERICAN SPECIES OF THE GENUS ATAX 243 



Claw with a very small accessory tip on the 



convex side of the principal one 



5. A. ahi&rmipes mihi, female. 



9. Last two acetabula placed side by side; claws 



bifid 8. A. fossulatus Koen. 



Acetabula placed in a continuous line; claws 



simple 9. A. striata mihi. 



10. Acetabula about nine on each side. Hind 



leg of male modified 6. A. indistinctus mihi. 



Acetabula 20 or more on each side 11. 



11. Distal segment of palpus expanded, quad- 

 rate and with two long curved claws. 

 Body slightly emarginate in male, and legs, 

 especially of females, with more or less ser- 

 rate spines 1. A. sevratus mihi. 



Distal segment of palpus slender, curved 



and ending in a blunt point armed with 

 small claw-like spines. Body not emargi- 

 nate behind and no serrate spines on the legs. 12. 



12. First pair of legs not noticeably thicker than 

 the rest; distal segment of the legs straight, 

 and claws large and with two long equal 



hooks 11. A. ypsilophdrus (Bonz). 



First pair of legs noticeably thicker than the 

 rest and tapering from base to tip; distal 

 segment slender, more or less arcuate and 

 claws small and bifid 13. 



13. Distal segment of legs decidedly arcuate; 

 fourth segment of palpus tapering from base 

 to apex. Maxillary shield with an ancoral 



process posteriorly 10. A. arcuata mihi. 



Distal segment of legs slightly arcuate; 

 fourth segment of palpus swollen and nearly 

 uniform in diameter from the base to the 

 paired papillae on the ventral surface. Max- 

 illary shield with no ancoral process poste- 

 riorly 12. A. tumidu-s mihi. 



