388 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxvii. 



.'/,'/■ i~^pines on last joint of hind tarsi in two rows on lateral margins, 

 ])ut with first pair slightly bent inward; labial palpi equaling or a 

 little exceeding fore coxfe. 

 h. Disk of vertex back of antennal groove with six stout bristles. 



iii^io (p. 406). 

 hh. Disk of vertex back of antennal groove with but one to three 

 stout bristles. 

 i. Pronotal ctenidiuni of twenty spines. 

 j. Joint III of hind tarsi with but two sets of spines on either 



margin canadensis ( p. 407 ) . 



jj. Joint III of hind tarsi with three sets of spines on either 



margin risoH (\). 408 ) . 



ii Pronotal ctenidium of sixteen spines lucidns (p. 410). 



ff. Hind tarsal joint II with an apical spine exceeding joints III and IV 

 together; hind femur with a row of minute bristles on side. 

 g. Eyes well developed; spines on fifth tarsal joint confined to two rows 

 on lateral margins, though the first pair may be slightly bent inward. 

 /(. Lal)ial palpi nearly equaling anterior femora. 



). Gena below eye obtusely pointed posteriorily; length, female 



2.75, male 1.75 montanus (p. 411). 



(/. Gena below eye sul)truncate posteriorily; length, female 3.75, 



male 2.75 arctomys (p. 411). 



hh. Labial palpi equaling or a little exceeding anterior trochanters. 

 i. First pair of spines on last tarsal joint slightly bent in- 

 ward proximus (p. 412). 



a First pair of spines on last tar.sal joint curved outward, same as 

 others. 



j. Upper male claspers at upper extremity obliquely truncate 

 toward body. The hind margin with one long and several 



short bristles hruneri (p. 413) . 



jj. Upper male claspers obliquely truncate away from body or 

 narrowed to a point above; hind margin with four long and 

 several short bristles. 



k. Genre broadly truncate posteriorly below eye; upper male 

 claspers distally gradually narrowed to a point. 



idaJioeyisis (p. 413.) 

 kk. Gena? pointed posteriorly below eye; upper male claspers 

 ol)liquely truncate away from body. 

 /. End of male abdomen with comparatively few long 



bristles arizonensls (p. 415 ) . 



II. End of male abdomen with a thick l)rush of long bristles 



on eighth segment petiolatns (p. 415). 



gg. Eyes rudimentary; first pair of spines on last tarsal joint dislocated 

 toward median line. 



/(. Labal i^alpi not equaling anterior coxa? ignotus (p. 416). 



/(//. Lal)al palpi exceeding anterior trochanters dicisus (p. 416). 



dd. Hind tarsal joint I equaling II, III, and V together. 

 e. A spine on apex of hind tarsal joint I much longer than joint II; front 



without the usual minute notch coloradensls (p. 417). 



ee. Spines on apex of hind tarsal joint I much shorter than II; front with 



the usual notch eremicus (p. 417) . 



cc. Males with a stout style projecting from seventh tergite over at least one- 

 third length of pygidium; size enormous; eyes absent sfijlosus (p. 418). 



