14 University of Michigan 



trace of cornicles or spinous points. Last tergite with caudal 

 margin obtusely angular at middle, wholly without furrows or pits. 



Ventral plates in general without distinct furrows; with a 

 network of lines over caudal and cephalic borders. Last ventral 

 plate narrowed caudad; the caudal margin shghtly incurved; 

 a median longitudinal furrow. 



Coxopleurae of pregenital segment not at all produced, caudally 

 simply rounded. 



First four pairs of legs with two tarsal spines, the fifth and 

 succeeding ones to the twentieth inclusive with one tarsal spine. 



Anal legs wholly unspined. 



Femur in male with a long process similar to that of scabri- 

 candus, etc., which arises from base on mesal side and attains the 

 distal end of the joint; this appendage flattened, its mesal edge 

 obtusely angled distad of its middle, appendage beyond this 

 weakly curved, distally rounded and bearing at distal end on dorsal 

 or submedian side a patch of golden-brown hair (Plate I, Fig. 3). 



Length, 52 mm. 



British Guiana, Dunoon: sand-hill forest, in rotten wood, 

 August 24, 1914, one male; "first mourie," August 26, 1914, one 

 male; and "second mourie," August 19 and 20, 1914, two females; 

 F. M. Gaige. 



Colombia: Cincinnati Coffee Plantation, July 5, 1913, F. M, 

 Gaige. 



Type, M.C.Z., 2180, from Dunoon, British Guiana. 



The species is related most nearly apparently to 0. scahricaudus 

 (Humbert and Saussure), but is distinguished by the wholly smooth 

 tergites and absence of median keels, the absence of median furrow 

 on sternites, and the form of the appendage of the femur of the 

 last legs, this being flattened rather than cylindrical with the end 

 rounded, not flattened, and the patch of golden-brown hair at the 

 side of the end, not at the middle of the distal surface, etc. 



