1G0 BULLETIN 46, UNITED STATES NATIONAL MUSEUM. 



II. Segments with 4 or 5 rows of tubercles (species brown- 

 ish) SCYTONOTUS Koch.* 



kk. Repugnatorial pore surrounded by a long oval swelling. 

 m. Lateral carinse projecting upwards, horn-like; back 



smooth Rhaciiidimorpha Saussure. 



mm. Lateral carina horizontal; back tuberculate. 

 n. Pairs of legs $ 30, 9 31. 

 o. Segmeuts with less than 3 rows of feebly developed 



tubercles RtiACOPHORUS.t — Koch. 



oo. Segments each with 3 rows of well-developed tuber- 

 cles Polydesmus Leach. 



ww. Pairs of legs $ 28, 2 29 Brachydesmus. — Heller. 



dd. Anal segment quadrate. 



j). Eepugnatorial pores placed on margin of carina}. 

 q. Anal plate not warty ; back smooth or with in- 

 distinct scale-like tubercles; first dorsal 

 plate as wide as second. 



Euryurus Koch. 

 qq. Anal plate with two warts ; back with scale- 

 like tubercles; first dorsal plate smaller 



than the second Polylijpis t Bollman. 



pp. Eepugnatorial pores placed on the upper side of 

 carinse. 

 r. Margins of lateral carina? not serrate; anal 

 segment ending in three points. 



Oxydesmus Humb. and Sauss. 

 rr. Margins of lateral carina? serrate; anal seg- 

 ment ending in two points. 



Stexoxia § Gray. 

 co. No swelling around the repugnatorial pore, which is somewhat above. 



Icosidesmus Humb. and Sauss. 

 bb. Femora of legs spined ; lateral carinas more or less bent downwards. 



Fontaria Gray. 

 act. Repugnatorial pores on the 5, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,. 18, 19 segments. 



Stroxgylodesiius Saussure. 

 ana. Repugnatorial pores on the 5, 7, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 segments. 



Eurydesmus Saussure. 

 (taact. Repugnatorial pores only on the fifth segment; femora armed with a spine. 



Stenodesmtjs Saussure. 



* Analysis of subgenera of Seytonotus. 



a . Anterior part of body not especially attenuated ; legs rather short 



Scytoxotus, s. str. 

 aa. Anterior part of body much attenuated; legs long; antenna? slender. 



Trachelodesmus Peters. 

 , Analysis of subgenera of Bhacophorus. 



a. First dorsal plate normal Rhacophorus, s. str. 



aa. First dorsal plate large, almost hiding head Ceyptodesmus Karsch. 



t Polylepis Bollman for Pachyitrns Saussure, which is preoccupied. 

 § Analysis of subgenera of Stenonia. 



a. Coxa? produced into a spine Acanthodesmus. 



aa. Coxa? not produced into a spine. 

 b. Body narrow; repugnatorial pores lateral; the second dorsal plate much wider 



than second Odoxtodesm us. 



bb. Body wide ; repugnatorial pores superior - Stexoxia, s. str. 



