380 PROCEEDINGS OF THE NATIONAL MUSEUM vol.90 



Fe?n^le.—Body slender, between four and five times as long as 

 wide, cylindrical, greatest diameter at the first thoracic segment, 

 gradually tapering posteriorly (fig. 18, d). Thorax and abdomen 

 arched ventrally in specimens preserved in alcohol. Cephalic seg- 

 ment nearly as long as the first three thoracic segments combined. 

 Cephalon well developed laterally, smoothly truncate posteriorly, 

 rather broadly rounded anteriorly, posterior half of dorsum with two 

 pairs of very small setae, the posterior pair slightly larger ; rostrum 

 very small, elongated-oval, with two minute curved setae on the an- 

 terior end. 



First segment of the 6-segmented thorax rather indistinctly sep- 

 arated from the cephalic segment, the dorsum shorter than either of 

 the following two dorsa and bearing a pair of minute setae ; another 

 small seta at the origin of both basipods. Second thoracic segment 

 with a pair of setae on the dorsum, two pairs laterally and two pairs 

 at the origin of the basipods, all five setae on one side more or less 

 linear and well separated from one another. Third segment with 

 similar setae, but with one additional lateral pair, making six pairs 

 in all: the dorsum a little shorter than that of the second segment. 

 Fourth segment similar to second. Fifth segment with shortest dor- 

 sum of all body segments, located at the center of the body arch and 

 often telescoped with the adjacent dorsa; three pairs of setae, one 

 on the dorsum, one laterally, and one near the base of the fifth legs. 

 Sixth segment of the thorax with a pair of setae on the dorsum and 

 another pair on the posterior lateral areas; a single genital opening 

 on the ventral side. 



Abdomen 4-segmented, segments narrowed but of about the same 

 length as the third and fourth thoracic segments, dorsa quadrangular 

 rather than rectangular. First abdominal segment with two pairs 

 of setae like those on the last thoracic (genital). Second with a 

 pair of setae on the dorsum, a vertical row of about 11 setae on the 

 lateral areas and a ventral transverse band of setae on the posterior 

 half. Third segment with a pair of setae on the dorsum, on both 

 sides a dorsolateral vertical row of seven setae and a lateral vertical 

 row of six setae, with a ventral transverse row of setae on the poste- 

 rior half. Fourth abdominal segment with slightly shorter dorsum 

 than the preceding ones, segment deeply incised at the center, with- 

 out anal operculum; a short transverse ventral row of setae on the 

 anterior part, a pair of setae on the dorsum, and on both sides a 

 row of setae on the dorsal, lateral, and ventral aspects of the posterior 

 part of the segment, adjacent to the origin of the anal laminae. 



Anal laminae much shorter than the terminal segment and stout, 

 both armed on the lateral aspect with three large setae (the middle one 

 one-half as long as the other two) in a vertical row, at the distal 



