142 bulletin: museum of comparative zoology. 



Antennae of uniform thickness beyond basal joint, reaching to or a little 

 beyond middle of second somite. Surface of head strongly granular excepting 

 loM'er middle region of labrum which is smooth. 



Collum exceeding the head in width. Widest in front of middle of length, 

 the caudal margin at sides bending more strongly forward to the lateral 

 processes than the anterior. Surface densely tuberculate throughout, the 

 tubercles larger laterad; a series of larger tubercles along anterior border and 

 one along caudal. 



Second tergite wider than those following; teeth or projecting tubercles 

 strongly marked along anterior edge; lateral margin also with sharply defined 

 teeth, these four in number between the corner ones, as on the third and 

 fourth tergites which are similarly strongly toothed on anterior edges of keels. 

 Succeeding keels mostly normally with four lateral teeth, though some of the 

 posterior ones have five. Teeth prominent but rounded and tuberculiform. 

 Pores dorsal in position and removed from lateral margin by from three to 

 four times their diameter (inclusive of rim). Dorsal surface of tergites with 

 three transverse rows of large, rounded, well-separated tubercles; between 

 these rows in middorsal region are scattered smaller tubercles, the surface 

 otherwise roughened with finer granulations, while laterad and especially on 

 the keels larger tubercles are present in the intervening spaces so that the rows 

 of large tubercles as such are there often not distinctly separable. 



Anal scutum subsemicircular, a little more strongly convex in middorsal 

 region, on each side of median caudal region three large but low crenations 

 from each of which arises a large seta. Proximally with transverse rows of 

 obscure tubercles; and on distal half two large setigerous tubercles. 



The gonopods of the male place the species in the relatively small group in 

 which the primary distal prongs are subdivided. Gonopod anteriorly curving 

 up dorsad and then caudad and again ventrad; near middle of anterior part 

 of this curve arises the first or ectal prong which is simple, the ventrally directed 

 tip acute; in the angle just above its base arises a much more slender, finely 

 pointed process of about equal length; the principal, more mesal and dorsal, 

 prong is tripartite, the ectal, more proximal, branch being straight and ex- 

 tending subectad, the other two branches curved, with the mesal one a little 

 stouter and longer than the other. 



Length of male (type), near 42 mm.; width, 8.2 mm. Width of female 

 to 9.25 mm. 



386. Platyrrhacus fallens, sp. nov. 



Type.— M. C. Z. 4,985. Paratype.— M. C. Z. 4,986. Solomons: 

 Fulakora (W. M. Mann). 



Metazonites dark brown; prozonites with brown in a spot on middorsal 

 region, on each side and ventrally, the intervening portions yellow; borders 



