22 BULLETIN 46, UNITED STATES NATIONAL MUSEUM. 



** Posterior angles of 9, 11, 13 dorsal plates produced. 

 a. Anal pair of feet armed with one spine; penultimate with two. 

 b. Coxa? unarmed; coxal pores in a single series. 



c. Antenna? 20-jointed; prosternal teeth 6; ocelli 25 Howei, sp. nov., 9. 



cc. Antenna? more than 30-jointed; claw of the female genitalia tripartite. 

 d. Coxal pores round, 7, 7, 6, 5; antennae 31-jointed; ocelli 27. -Aztecus, 10. 

 dd. Coxal pores transverse, 6, 6, 6, 4-9, 10, 9, 6; joints of antenna? 33-43; 



ocelli 23-48 Forficatus, 11. 



bb. Coxa? armed with a single rohust spine; coxal pores multiseriate ; prosternal 



teeth 15-20 ; joints of antenna? 20, long Xanti, 12 



aa. Anal and penultimate feet each armed with two spines; coxa? unarmed; joints 



of the antenna? 20 ; prosternal teeth 4 Politus, 13. 



*** Posterior angles of the 7, 9, 11, 13 dorsal plates produced. 

 a. Anal feet armed with one spine; coxa? unarmed; coxal pores in a single series. 

 b. Penultimate pair of feet armed in the two spines ; j oints of antenna? 31-38 ; 

 prosternal teeth 12-14; coxal pores 7, 7, 6, 5, 10, 10, 10, 9, trans- 

 verse; spines of the first pair of feet 2, 2, 1, 3, 3, 2. ..Mordax, 14. 

 bb. Penultimate pair of feet armed with three spines; joints of antenna? 26-30; 

 prosternal teeth 8; coxal pores 4, 4, 5, 2, 4, 5, 5, 4, round; spines 



of the first pair of feet 1,3,2,2,3,2 Clarus, 15. 



**** Posterior angles of the 6, 7, 9, 11, 13 dorsal plates produced. 

 a. Anal feet with a single spine; coxa? armed; coxal pores multiseriate; joints of 

 antenna? 19-23 ; prosternal teeth 14-18; spines of the first pair of 

 feet 2, 3, 1-2, 3, 2 Multidentatus, 17. 



Subgenus Archilithobius Stuxberg. 



1. Lithobius kochii Stuxberg. 



Lithobius kochii Stuxberg, Ofver. Kongl. Vetens.-Akad. Fordhandl., 68, 1875 



(Saueelito, Cal.) 



To this species I refer a specimen from Ukiah, Cal., which has lost 



the antennse and nearly all the feet. It has 11 ocelli, arranged in 5 



series, prosternal teeth 4, small; coxal pores 3, 4, 4, 3, small and round ; 



color fulvous. 



2. Lithobius minnesotae, sp. nov. 



Brown, head darkest, feet and ventral laminae not much paler ; tip of 

 antennae and prehensorial feet rufous. 



Slender, smooth; very sparsely pilose. Head subcordate, wider than 

 long (3. 5:3), smooth, very sparsely hirsute. 



Antennae short, joints 20, mostly long; the last long and sharp, 

 densely hirsute. 



Ocelli 13, arranged in 6 series. 



Prosternal teeth 4, small and indistinct. 



Coxal pores 4, 5, 5, 4, rather small, round. 



Spines of the first pair of feet 1, 3, 2; penultimate 1, 3, 3, 1; last 

 pair 1, 3, 2, 1. 



Posterior pair of feet moderately long and slightly swollen. 



Claw of the female genitalia moderately wide, tripartite, the middle 

 lobe much longer; spines robust, subequal. 



Length of body 16" 1U1 ; last pair of legs 5 mm . 



Habitat. — Fort Snelling, Minn. 



