44 University of Michigan 



Contrasting strongly with the previous species not only in 

 color Init also in form from the great narrowness of the carinae, 

 this giving the body a nearly cylindrical appearance. The 

 carinae in general are so narrow that the poriferous swelling 

 occupies the entire width in posterior part, with the part in 

 front still narrower, merging into the general surface of the 

 segment. Anterior keels wider than the posterior ones. Pos- 

 terior angles slightly produced from fifth segment caudad. 

 Dorsal surface of segments divided into polygonal areas as in 

 P. colomhicnsis, but tubercles absent or obsolete and irregu- 

 larly developed. Some metazonites more or less roughened 

 toward the keels. See further, PI. 17, Figs. 114 and 115. 



Caudal margin of last tergite strongly convex, the sides 

 converging caudad. 



Gonopods of male as shown in PI. 17, Fig. 116. 



Length, about 45 mm. ; width, 6.5 mm. 



Colombia: San Lorenzo. A female in its "mud nest" with 

 eggs was taken under a log at 5,300 feet elevation, and a male 

 under a log at 5,000 feet, July 23, 1913. Holotype, M. C. Z., 

 5.125. 



Pl.ATVKRH ACIUAi: 



Rhyphodesmus amphelictus, sp. nov. 

 PI. 18, Figs. 117, 118 



General color dark brown, the keels scarcely paler, but the 

 Cauda over all but anterior portion abruptly lighter. 



Surface of head densely granular, with granules of differ- 

 ent sizes. A deep furrow across vertex, widening anteriorly 

 to occupy entire space between the rims of antennal sockets. 



Collum much narrower than the second tergite (width 

 about as 7.25 to 10) ; lateral end in general outline subrectan- 

 gular, but a little rounded at apex. Surface densely granular, 



