160 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. 

 in. Lateral carime projecting upwards, horn-like; back 



smooth '. RHACHIDIMORPHA Saussure. 



mm. Lateral carinse horizontal; back tuberculate. 

 . Pairs of legs $ 30, 9 31. 



o. Segments with less than 3 rows of feebly developed 



tubercles RiiACOPHORUS.t Koch. 



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

 cles POLYDESMUS Leach. 



H. Pairs of legs $ 28, 9 29 BRACHYDESMUS. Heller. 



dd. Anal segment quadrate. 



p. Repugnatorial pores placed on margin of carinae. 

 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 POLYLKPIS } Bollmau. 



pp. Repugnatorial pores placed on the upper side of 



carinae. 



r. Margins of lateral carinae not serrate; anal 

 segment ending in three points. 



OXYDESMUS Humb. and Sauss. 

 rr. Margins of lateral carime serrate; anal seg- 

 ment ending in two points. 



STENONIA Gray . 

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



ICOSIDESMUS Humb. and Sauss. 

 1)1). Femora of legs spint-d ; lateral carime more or less bent downwards. 



FOXTARI.A Gray. 



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



STRONGYLODESMUS Saussure. 



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



EURYDESMUS Saiissure. 

 uaaa. Repuguatorial pores only on the fifth segment; femora armed with a spine. 



STENODESMUS Saussure. 



* Analysis of siibycnera of Scytonotns. 



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



ScYTOxoTrs, s. str. 

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



TRACHELODESMUS Peters. 

 , Analysis of sulxjciu'ra of Bhacopltorus. 



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



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



t Polylepls Bollmau for Pacliyurux Saussure, which is preoccupied. 



Analysis of mihi/cinrd of xtaionia. 



a. Coxa? produced into a spine ACANTHODESMUS. 



aw. Coxa> not produced into a spine. 



ft. Body narrow; repugnatorial pores l;itcral ; the second dorsal plate much wider 



than second ODONTODKSMI'S. 



l>b. Body Avjde ; repugnatorial pores superior STKNOMA, s. str. 



