190 COSTA RICAN MYRIAPODA 



brown tinge; the yellow lateral band across the keels of each side distinctly 

 narrower than the median black band; on some of the tergites (in female 

 from Reventazon Road) a rather obscurely outlined paler spot may be pres- 

 ent in border of black band on each side. Head black excepting labial 

 border which is yellowish. Antennae and legs uniform brown. 



Head roughened, finely coriarious and shagreened, excepting labial area 

 which remains smooth; bordering upper edge of labrum a conspicuous 

 transverse setiferous ridge. Vertex with a conspicuous larger tubercle on 

 each side. Median sulcus distinct, passing into a broad depression between 

 antennae. Rim of antennal sockets on dorsal side elevated and thickened. 

 A median longitudinal ridge-like elevation beginning between antennae 

 and passing ventrad to bifurcate at clypeal region like an inverted Y, the 

 branches coarser and more tubercular in character; area between branches 

 smoother than other parts excepting the labrum (this ridge more indistinct 

 in female from Reventazon Road). 



Antennae reaching a little caudad of posterior border of first dorsal plate. 

 Sixth segment long and, as commonly so, of smaller diameter than the pre- 

 ceding segments. 



First dorsal plate wider than the head. Anterior margin lightly convex; 

 margin laterally slanting back ectocaudad to the posterior angle which 

 is less than rectangular, this lateral part of margin distinctly sinuate, there 

 being four crenations. Caudal margin between angles bow-shaped but 

 with median portion straight. A row of small tubercles along anterior and 

 posterior borders. Entire surface granular or shagreened. 



Keels of second tergite bent forwards. Both anterior and posterior 

 angles rounded but the latter less so. Lateral margin conspicuously crenate, 

 the elevations regular. 



In succeeding tergites the keels become more and more nearly trans- 

 verse; the posterior corner becomes more angular and then produced caudad 

 at first weakly and then more strongly and acutely, in posterior segments 

 becoming spinose; on nineteenth tergite the processes of keels are large but 

 bluntly rounded while those of the eighteenth are subacute though broader 

 and less sharp than in preceding segments. Lateral margin of keels in 

 proceeding caudad becoming conspicuously irregular and often deeplj' 

 notched, but in eighteenth and nineteenth wholly smooth. Anterior edge 

 of keels from eleventh to eighteenth finely serrulate and the caudal margin 

 serrulate from sixth or seventh to seventeenth. Pores large; on all but last 

 two tergites removed by less than twice their diameter from nearest point 

 on margin. Surface of all tergites densely finely tubercular or shagreened. 



Anal tergite with caudal margins rounded, semi-circular. Proximal 

 portion finely shagreened, the distal portion under lens appearing more 

 finely coriarious. 



Anal valves with mesal margins elevated. Two setigerous tubercles 

 just ectad of mesal marginal elevation on each side, one behind the other. 

 Surface irregularly tubercular. 



Anal scale with caudal margin between tubercles straight or weakly 

 incurved. 



