1901.] MXBIAPODA 01 THE " SKEAT EXPEDITION." 515 



12th tergite. The 12th keel has the posterior angle produced into 

 a spine, though not a long one. The posterolateral margin of the 

 keels is finely serrated after the 10th somite. 



Anal tergite. The anal tergite is rounded at the posterior edge, 

 and shows long longitudinal elevations resembling those on the 

 anal tergite of P. humberti, but differently arranged. They each 

 end posteriorly in a tubercle, which bears a r-eta. The edge of the 

 tergite is indistinctly divided into five lobes. 



Sterna. The sterua are non-sulcate, and slightly marked with 

 wrinkle-like elevations. The anal sternite is triangular, with two 

 long setiferous tubercles ; the anal valves have strongly marked 

 edges, with a single setiferous tubercle on the edge of each. There 

 are no setiferous tubercles on the outside of the anal valves. 



There is a single tubercle at the base of each leg on the internal 

 side, and on the external side there are three in a row 7 , the posterior 

 tubercle being partly divided into two. 



2nd specimen, 19 somites. Length 72 mm., width 1!) mm. 



The teeth on the posterior margin of the keels are visible on 

 the 8th somite. The lobes on the keels and the marks on the anal 

 sternite are all more prominent than in the older specimen. 



3rd specimen. This specimen has only 18 somites. Length 

 62 mm., width 8| mm. 



Colour clear brown-yellow ; prozonites darker, almost chocolate ; 

 the colour of the whole body is darker anteriorly. The lobes of 

 the keels are much more clearly marked, and the rows of tubercles 

 more distinct. The markings on the anal tergite less ridged, and 

 more like tubercles. The five lobes of the keels can be traced even 

 on the 2nd somite. The pore is placed just interior to the second 

 posterior lobe of the keel (that is, rather more posteriorly than in 

 the older specimens). 



Platyrhacus peeifeer.e Humbert ife Saussure. (Plate XXXL 

 figs. 37, 11, 1-5, 18, 50.) 



Prom Bukit Besar, Jala District. 

 Length 112 mm. 



mm. "iiu. 



Width of 1st tergite 9| Width of 16th tergite L5 .'. 



2nd „ 13 „ 17th „ 14.| 



3rd ., L3^ „ 18th „ \2\ 



4th „ 14 ,. 19th „ 8] 



5th .. L6 

 Colour black, shading into testaceous at edges of keels and 

 margin of anal tergite. Antenna, legs, sterna, and most of the 

 under surface of the keels chocolate. 



Head rough, and covered with small tubercles. Frontal furrow 

 deep, and widening out to a aemioval depression between the 

 antennas. Upper lip with a semicircular depression above it, and 

 four bristle-bearing tubercles along its edge. Length of antennae 



10! nun. 



Ut tergite. Anterior margin straight, with ridge but no distinct 



