356 



cT Length about 60 mm.; width of 10«' 8.5; of l 8 * 5; length 

 of l»t 3. 



9 (young with 18 somites). Length 27, width of 10th 5.7, of l 8t 3.5, 

 length of 1 st 1.7. 



51. Platyrhachus bidens, sp. n. PI. XXI, fig. 2 — 2 b . 

 Sumatra: Paningahan. 



Colour black, the tips of the carinal processes only being white; 

 legs ochraceous proximally. 



Head granular above, with frontal-sulcus. 



Antennas long, a little more than twice the length of the head, 

 the segments subequal in length. 



The first tergite with a deep furrow before the anterior border and 

 a row of round tubercles along it, its surface nearly flat and granu- 

 lar; its keels well developed, directed obliquely upwards and back- 

 wards, subcylindrical , stouter at the base than at the apex. The keels 

 of the second, third and fourth segments alike in character, rod- 

 like, about twice as wide as long, the anterior and posterior margins 

 sub-parallel, the lateral margin distinctly bifid, inclined obliquely up- 

 wards. The rest of the keels also alike , inclined upwards and outwards 

 and, from about the 10 th somite, slightly backwards, a little wider 

 than long or towards the posterior end of the body about as wide 

 as long, the anterior and posterior margins sub-parallel, the lateral 

 margin very deeply emarginate, each of the two lateral angles taking 

 the form of a long and strong tapering tooth; the keel of the 19 th 

 somite not only small, not bidentate. The dorsal surface dull, not 

 quite smooth, with a row of tubercles along the hind margin of 

 each somite. Pores situated at the base of the posterior side of the 

 anterior projection of the keels. Sides of the somites , finely granular. 

 Sterna not spined, although with a low tubercle at the base of 

 each leg; longitudinally and transversely scooped out. Caudal process 

 squared, with parallel sides, very lightly convex, sublobate posterior 

 border. 



Legs normally formed. 



Copulatory foot slender, lightly curved, terminating in two sub- 

 equal slender processes which are curved upwards and backwards, the 

 superior being a little shorter and a little more curved than the 

 inferior. 



