64 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 89 



Last segment fully exposed from above ; the dorsum with two 

 ridges ; the posterior margin widely rounded at middle and with two 

 lateral lobes, of which the lowest is the largest. 



Anal valves slightly convex, with rather broad, low margins ; sur- 

 face sparsely and minutely hispid. 



Preanal scale triangular, the surface also minutely hispid. 



Gonopods as shown in figure 31, c?. 



Sterna narrow and similar in the sexes. 



Third male legs with the middle joints slightly more swollen than 

 those of the adjacent legs. 



The incrustation of dirt on the dorsum is removed with difficulty, 

 but when this is accomplished, the surface of the segment is shown to 

 be strongly shining and with a faintly impressed median line present. 

 The dorsal ridges in reality are each seen to be composed of three 

 separate tubercles tipped with numerous fine setae ; and the raised 

 margins of the segments are formed of closely placed hairs which 

 catch and hold dirt; these hairs are longest on the lateral keels (fig. 

 31, e). The tubercles of segment i are hispid at the apex, and the 

 margins of the anterior lobes have a continuous series of long hairs 

 similar to the margins of the keels of the ensuing segments. Pores 

 opening from tiny conic prominences on the posterior lobe of the keels ; 

 this lobe is longer and broader than the anterior lobe ; the posterior 

 margin of the keel is deeply emarginate, and there is a lobe or tubercle 

 on the posterior margin of the dorsum at the base of each keel. 



BOTRYDESMUS LUTOSUS, n. sp. 



A single male and over a score of females were found on the under 

 side of a log in a clearing of the Arena Forest, Trinidad, February 16, 

 1932. 



Description. — Length from 4 to 4.5 mm, width from .5 to .6 mm. 



The living animals were buff-colored, the color being derived from 

 the incrustation of earth rather than from any pigment in the body, 

 which probably was pure white as in the cleaned alcoholic specimens. 



Other characters given in the generic description. 



Ty/)^.— U.S.N.M. no. 1108. 



Family COMODESMIDAE 

 INODESMUS Cook 



Laslodesmiis Silvestri, Bull. Amer. Mus. Nat. Hist., vol. 24, pp. 575, 576, 1908. 



