1887.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 255 



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

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

 h. Coxaj unarmed ; coxal pores in a single series. 



c. AntenutB 20-joiuted ; prosternal teeth 6 ; ocelli 2.5, HoWEi, sp. uov., 9. 



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

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

 (Id. Coxal pores transverse 6, 6, 6, 4-9, 10, 9, 6 ; joints of antennas 33-43 ; ocelli 



23-48, FoKFiCATUS, 11. 



hb. Coxas armed with a single robust spine ; coxal pores multiseriate ; prosternal 



teeth 15-20; joints of antenna) 20, long, Xaxtt, 12. 



rtfl. Anal and penultimate feet each armed with two spines ; coxas 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; coxse unarmed; coxal pores in a single series. 

 h. Penultimate pair of feet armed in the two spines ; joints 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 jiair of feet armed with three spines ; joints of antenna) 26-30; 

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



the firstpair of feet 1,3,2,2, 3, 2, Clakus, 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 

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

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



Subgenus ArcMlWiobms Stuxberg. 



1. Lithobius kochii Stuxberg. 



Lithobius kochii Stuxberg, Afver. Kongl. Vetens.-Akad. Forhandl., 68, 1875. 

 (Saucelito, Cal.) 



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

 the antennae 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. uov. 



Brown, head darkest, feet and ventral laminoe not much i^aler ; tip of 

 antennse and prehensorial feet rufous. 



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

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



Antenna? short, joints 20, mostly long; the last long and sharp, 

 densely hirsute. 



Ocelli 13, arranged in G 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™™; last pair of legs 5™™. 



Habitat. — Fort Snelline-, Minnesota. 



