456 PROCEEDINGS OF THE NATIONAL MUSEUM. 



Preaual scale broadly triangular, setiferous tubercles distinct. 



Sterna, very narrow, tlie coxu' nearly in contact. 



Legs sparsely hirsute, the third joint with a few long hairs on the 

 ventral face, the succeeding Joints with hairs shorter and more 

 numerous. 



The specimen Avhich serves as the type of this species is preserved 

 in alcohol and is marked as a type of ()msco(les7ni(.s ruhric('2),s Peters, 

 with which, as represented by the dried specimen supposed to be the 

 true type, it has no close relationship, as a comi)arison of the drawings 

 will show. 



From Oniseodestmis onucinus the present form dift'ers most conspicu- 

 ously in the structure of the last two segments. 



Genus LIGN YDESMUS Cook. 

 Lignydesinus COOK, Brandtia, 1896, p. 28. 



Second segment with anterior marginal ridge very prominent and 

 broad, expanded below into a broad marginal rim. 



Segments with posterior areate margin very convex and long, occu- 

 pying over a tliird of the surface of the individual segments; surface 

 of segments covered with a black adherent bloom or powder. 



llepugnatorial pores h)cated in contact with the transverse sulcus 

 which bounds the areate margin, and elevated on a distinct rounded 

 tubercle. 



Segment 19 with subrectangular sinus exposing the broadly rounded 

 last segment. 



LIGNYDESMUS RUBRICEPS (Peters). 



(Plate XXX, ligs. '2a-2f.) 



Oniacodefimiis ruhriceps Pktkrs, Monatsber, K. Akjid. Wiss. IScrliii, 18(54, p. 617. 

 LigtiUdesiiins riibriceps CooK, IJraiultia, 1896, p. 28. 



Type. — Berlin Museum, a dried specimen. 

 Locality. — Bogota, Colombia. 



Genus DETODESMUS Cook. 

 J)eio(le>iinii8 Cook, Urandtia, 18!lti, ]>. 28. 



Second segment expanded in front on each side of the middle so that 

 the lateral aspect is somewhat semicircular; anterior margin narrow 

 and not so prominent as in Lidnydtsniiis; areate margin wanting. 



Segments with areate margin very short, occupying less than one- 

 f(mrth of tlie dorsal surface; areas small; surface of segments clean 

 and polished. 



Repugnatorial jiores distinctly removed from the areate margin, not 

 elevated on a tubercle. 



Segment 10 with a rounded sinus about as wide as its carinaj ; exposed 

 part of last segment broadly rounded. 



