530 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
Margin of prosternum 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, 
fier 2). 
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. As 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 (0”). 
Length near 30 mm. 
Locatiry.— Swan Island, April 13, 1913 (George Nelson). TyPs, 
M. C. Z. 1716; one male. 
