174 Mr. R. I. Pocock on the Genus Urodacus. 



Urodacus ahruptus, sp. n. (PI. VIII. figs. 4, 4 a.) 



Cephalothorax with a conspicuous incision in the middle of 

 its anterior margin, marked throughout its length bj a median 

 sulcus, which near the hind margin terminates in a deep 

 transverse depression, the sulcus and depression somewhat 

 resembling respectively the handle and head of a hammer. 

 The anterior and posterior terminations of the right and left 

 portions of the ocular tubercle scarcely at all continuous 

 behind and in front with the margins of this sulcus. Anterior 

 third of cephalothorax above smooth and horizontal, posterior 

 two thirds thickly granular and laterally depressed ; margins 

 of the frontal lobes defined by a very shallow sulcus ; eyes a 

 little further from the anterior than from the posterior margin. 

 . Sides and posterior margins of the first six abdominal ter- 

 gites granular, the rest smooth and shining ; the anterior 

 tergites more granular than the posterior ; each of these ter- 

 gites marked with four impressions, two anterior and crescentic, 

 two posterior and straight ; posterior tergite granular and 

 furnished on each side with two short keels. 



Sternites smooth and shining, marked with the usual abbre- 

 viated depressions ; posterior tergite marked with four smooth 

 keels, two near the middle line being very short. 



Caudal keels well developed, the three inferior keels on the 

 first three segments smooth, those of the fourth finely denti- 

 culate ; the superior and supero-lateral keels of the first four 

 segments denticulate, the posterior denticle of the superior 

 keel being the largest ; intercarinal spaces of these segments 

 very finely granular j superior surface of the fifth segment 

 distally flat ; superior keels very finely denticulated, the three 

 inferior keels strongly denticulate, the denticulations increasing 

 in size from before backwards, lateral and inferior inter- 

 carinal spaces granular ; vesicle below punctured, furnished 

 beneath with two shallow sulci and on each side with one 

 sulcus ; aculeus slightly curved. 



Superior surface of humerus sparsely and coarsely granular, 

 bounded in front and behind by a row of denticles ; anterior 

 surface finely granular, with a few larger tubercles ; posterior 

 surface smooth, not separated from the inferior surface by a 

 row of tubercles ; inferior surface proximally granular. Bra- 

 chium almost smooth, very finely granular above and with 

 the upper and lower margins of the anterior surface very 

 slightly roughened j inferior surface marked behind with a 

 keel, upon the anterior side of which is a series of setiferous 

 punctures. 



