ART. 8. Mn.TJFEDS OF CENTRAL. AMERICA — CHAMBERLIN. 37 



Localities. — Costa Rica : Three females and one male, collected by 

 C. Bergdorf and P. Schild (Ace 38,962, U.S.N.M.) ; Nicaragua: San 

 Juan del Norte, a female, collected by J. F. Le Baron and compared 

 with the type in Berlin Museum by O. F, Cook ; also Macliucha, one 

 male, collected by Dr. J. E, Bransford. 



Carl separates his species hiollyi from ^itnbriatus because the type 

 of the former does not show polygonal areas on the metazonites. 

 These were also not evident on some of the specimens listed above 

 when they were dry, but in all they became distinct when thoroughly 

 clean or when in liquid. The gonopods are as figured by Carl for 

 hiollyi^ and it is likely that this form is the same species as ftmhriatus. 



Genus NYSSODESMUS Cook. 



Nyssodesmus Cook, Brancltia. vol. 12, 1896, p. 53. 



The original diagnosis of this genus was based upon specimens 

 in the Berlin Museum of a species as yet undescribed, though listed 

 as the genotype under the name ;V. alboalatus. While it seems im- 

 possible to identify this Nicaraguan species from the facts included 

 in the generic diagnosis, the latter applies clearly to the three new 

 species here described and probably equally well to the others here 

 listed. Nyssodesmvs is used in preference to Platyrachus because 

 of the indefiniteness of our present knowledge concerning the real 

 characters of the latter in any restricted sense. 



84. NYSSODESMUS NIGRICAUDUS, new spedea. 



Plate 15, figs. 4-8. 



In coloration v^vy similar to N. hivirgatus (Carl), the keels and 

 a broad dorsal band being yellow, while a narrower stripe along 

 each side just within bases of keels is dark brown or blackish. The 

 entire last tergite is black, as is also the caudal border of the preced- 

 ing segment, whereas the caudal process in hivirgatus is yellow. 

 The head is blackish and lacks the yellow patch on vertex that is 

 present in hivirgatus. Legs and antennae dark brown. Vertex of 

 head roughened, with a rounded elevation on each side of the median 

 furrow, having at its summit a large, transversely elongate, smooth 

 tubercle, prominent ridge along mesocaudal border of antennal 

 socket. Collum broader than head, its anterior margin over middle 

 region weakly convex; side lobes bluntly triangular, the anterior 

 margin adjacent to angle with two or three tubercles or rounded 

 teeth projecting forward and several obsolete ones mesad of these. 

 Dorsal surface densely granulo-roughened, the anterior row of tu- 

 bercles evident, but the posterior one obsolete in the type (see pi. 15, 

 fig. 4). Keels broader than long. The pores are located far outside 



