724 PROVEEDlNaS OF THE NATIONAL MUSEUM. vouxxi. 



Segment 19 nearly concealed, its carinio small and rounded, 

 exceeded by those of segment 18. 



Last segment (abnormally'?) very broad and rounded, the apex not 

 l)r()duced nor truncate, somewhat exceeded by the margins of the anal 

 valves. 



Anal valves witli margins scarcely distinct, not compressed nor 

 prominent; setiferous tubercles distinct, the superior pair somewhat at 

 the side of the margin instead of upon it; surface of anal valves and 

 preanal scale faintly rugulose. 



Sterna sparsely hirsute with long hairs on the posterior slope, 

 otherwise nearly naked. 



Sternum of segment G with process nearly naked, the mesial 

 prominence of the basal joints of the sixth pair of legs with long hairs. 



Sternum of segment 15 with i)rocess very broadly triangular, 

 pointed, scarcely canaliculate. 



Legs of male moderately hirsute, the anterior somewhat more 

 densely than the others. 



Copulatory legs (Plate LIX, figs, la-ic). 



Color of alcoholic specimen pale bone yellow. 



Length, 28 mm,; width, G mm.; witliout cariuio, 4.3 mm.; length of 

 antenna', 5 mm. ; of leg from tenth segment, G mm. 



Locality. — A single male specimen in the Berlin Museum was 

 collected by Denhardt at Witu, British p]ast Africa. 



SIGODESMUS MONOCERUS, new species. 

 (Plate LIX, tigs. 3a, 36.) 



Differs from the preceding in the much greater size and somewhat 

 more robust habit. 



The copulatory legs, while clearly more similar to those of S. incUffus 

 than to any otjier species, are strikingly distinct in the shorter and 

 more robust ilagellum, the longer i)rong of S. indu/ns being replaced 

 by a thickened, rounded prominence. The other prong is here some- 

 what larger and more strongly curved than in the other species. Of 

 the two large teeth opposite the node of S. indigus, the shorter is here 

 rudimentary, while the other is much smaller than in that species. 



Color of fresh alcoholic material light grayish brown on carin.c and 

 anterior subsegraents, the posterior half of the posterior subsegment 

 being also light dorsally; the anterior half, and especially a large but 

 somewhat irregular and mottled patch at the l)ase of the carina, dark 

 brown; this darker marking is usually well defined and sometimes 

 very conspicuous. The transverse sulcus, at least, is dorsally very 

 dark brown, with a dark median line and a lateral patch on the ante- 

 rior subsegment at the height of that of the posterior subsegment, but 

 smaller, lighter, and i)oorly defined. 



Length of male, about 47 mm.; diameter, 11.5 mm.; length of 

 antenna, 9 mm.; of leg of tenth segment, 10 mm. 



