530 bulletin: museum of compaeative zoology. 



Margin of presternum between prehensors forming an obtuse 

 reentrant angle; wholly unarmed. Sides convex, strongly converging 

 caudad. Chitinous lines strongly developed, complete: 1.36 times 

 wider than long. 



Anterior prescuta short, the median and posterior ones becoming 

 long. 



Spiracles all circular or the first one a little vertically elongate. 

 First larger than the second, the others gradually decreasing caudad 

 and in the posterior region minute. 



Anterior ventral plates with the caudal margin angularly produced 

 and extending into a corresponding shallow excavation in anterior 

 border of succeeding plate. The excavation expanding on sternites 

 from twelfth to twentieth into a clearly limited, large, transversely 

 elliptic depressed area which is strongly chitinized. 



Last ventral plate wide; wider than long; sides convex, converging 

 caudad; caudal margin weakly concave over entire length (Plate 4, 



Ventral pores present on anterior sternites in a transverse band a 

 little caudad of middle. Pores also present on caudal plates but 

 fewer the area showing a tendency to be divided at the middle. 

 The pores detected on sternites of middle region of body. 



Coxopleurae small, not inflated. Pores small, few; opening be- 

 neath edge of sternite. 



Dorsal plates distinctly bisulcate. 



Last dorsal plate very broad. x\s wide anteriorly as the penult 

 tergite. Sides convex, strongly converging caudad, the caudal end 

 being rather narrow, rounded. 



First pair of legs a little shorter and more slender than the second 

 which are nearly as large as the third. Anterior pairs of legs shorter 

 and stouter than the posterior. 



Anal legs very much longer and thicker than the penult. In the 

 male much inflated, a little thicker dorsoventrally than laterally. 

 Second tarsal article abruptly and greatly more slender and the first 

 article intermediate but still much more slender than the proximal 

 ones. Claw well developed. Hairs sparse, moderately long. 



Pairs of legs 60 (cf). 



Length near 30 mm. 



Locality. — Swan Island, April 13, 1913 (George Nelson). Type, 

 M. C. Z. 1716; one male. 



