THE MVKIAPODA OF NORTH AMERICA, 141 



IH, POI.YUKHMIN.K. 



1H72.— Po/^dcjimi(i Mumli«rt itnd Sanmiirr'. MiM. Hoientif. Mex. Zool., vi, 25 (te$tt 



Lat/.fh. 

 IXiH). — ('riiptoilmmoifUa KarMth, Mittlivil. Miiiicli. Eiit. Vrr., H'.\. 



The subfiiinili«'« of Pohf<ltHHUil<r rstaltlishctl by lliuubcrt aii<i Sans- 

 sure and also retaiiml l>y Lat/el seem to iiu* to hv worthy of their rank. 



In aecrordance with coiniuon (;ust>»ni I liave ehau^ed Ptdydoimia to 

 Volyik'smimK, 



19. SPIMCKlOUKSMtN^. 



IH72. — SplitfriiMleMiHia Hiiiiilu>rt iind Shuhhuh'. MImm. m'i««utif. Mex. Zo<il., vi,'JO (leaie 

 Lutzel;. 



20. Lki'Todksmuh. 



1W7.— Oj-i/urM« Koch. ;,yBt. Myr., m and 13J» (rfHtitu»). 



IH')\K — LiitlotlfumiiH iSauMHure. liiiiii. Ent., .Mil, 32H {ijrnnuloHU»). 



As OxifuruH Koeh is i)reo<«iii>ie»l {itxyuruH Raf., Pisces, 1810; Oxyurun 

 Swains., Aves, 18L'7), LeptodeHmm Saussure, must be employed instead 

 of Oxyurus. 



21. RiiAroPliOKUS. 



1>*47. — Rhacophornt Koch. SyHt. Myr., 59 au.l 137 (PoUj. connperauH Pprty). 



lMti4. — CifiplodenmHn IVtcrn. Mouatsher. Icon. preiiHH. .\ka<l. Wiss., 621 (alatiig, etc.). 



CryptodexmuH has been rightly considered by Latzel as being a sub- 

 genus of RhacophoruH. 

 Tlie foUowing is a key to the subgenera: 



a. First dorsal plate normul, not concealinj; the head Kiiacopmoui's. 



aa. First dorsal plate strongly produced forward and completely concealing the head. 



Cryitodks.mcs. 

 22. Stenonia. 



1842.— .S7cnf»nirt Gray. Todd's Cyclop. Anat. anil Phys., ill, .546 (dritii). 



1S47. — I'latiirhavim Koch. Syst. Myr., 'yd and 131 (nvaber =^ Stenonia, ». ntr.). 



1860. — (tdoHtodcHinuH .Saiissure. Myr. Mex.. 70 (juvanuK). 



1864. — Acanthodvxmiix Peters. Mouatsber. kon. preuss. Akad. Wiss., 547 {Hculatua^ etc.) 



Platyrkacus, OdontodeHmus and Acanthodcfimus have been considered 

 as subgenera of Sffnonia; but as Stenonia has not been properly sub- 

 divided — no subgenus Stenonia having been setai)art — I have compiled 

 the following analytical key for the separati«m of the subgenera: 



a. Basal joint of legs not provided with a s]>ine. 



b. Body slender, lateral carina- moderately developed, repuguatorial pores sub- 

 marginal, second dorsal i)late much wider than the first Odontodks.mus. 



bb. Body wide; lateral cariuic strongly developed; repuguatorial pores superior, 

 more or less distar.t from lateral margin of carina' ; secoud dorsal plate normal. 



Stknoma. 

 aa. Basal joint of legs armed with a spine Acanthoi>E8MU8. 



23. SCYTONOTU.S. 



1847. — Scytonotus Koch. Syst. Myr., .57 and 130 {HcabricoUis^granulalHS Say). 

 1864. — TrachelodeHmiis Peters, Mt)natsber. kiin. preuss. Akad. Wiss., 623 {canstt icttt$) . 



