188 COSTA RICAN MYRIAPODA 



Anal tergite with sides meeting posteriorly at angle of about 90° or a little 

 greater, the angle narrowly rounded. Not covering the upper angles of 

 anal valves which extend clearly farther caudad. Anterior portion of sur- 

 face under lens seen to be weakly and finely coriarious the caudal portion 

 more strongly so but much weaker than on posterior division of prozonite 

 of trunk segments. 



Anal valves with mesal edges compressed and conspicuously protruding 

 but with no margining sulcus. Smooth and shining or under lens showing 

 obscure coriarious markings. 



Anal scale caudad extended in linguiform process which is distally sub- 

 acute. Process smooth and shining, the other parts finely roughened. 



The gonopods are very similar to those of R. costaricensis Brolemann. 

 The accessory branch is very broad, laminate, and is distally more acute 

 than in costaricensis. The stile is straight and slender, longer and distally 

 more acute than in the other species. The gonopod curves evenly, being 

 not at all geniculate. 



Number of segments 44 (cf ). 



Length about 93 mm. 



Locality. — Rio Oro Valley near Cachi (March 8, 1910). One 

 male. 



Closely related to R. costaricensis Brolemann, but differing, 

 among other points, in having the posterior division of the prozo- 

 nites strongly roughened instead of smooth; in differently shaped 

 anal tergite which does not cover angles of valves; in having sco- 

 bina on a much larger number of segments; and to some extent in 

 the gonopods. 



POLYDESMOIDEA 



PERIDONTODESMIDAE 



Peridontodesmus electus sp. nov. 



Dorsum uniform testaceous to light brown, individuals in full color 

 showing typically along dorsum a median longitudinal black line. Venter 

 and legs lighter, yellow to testaceous. 



Body narrowing slightly cephalad and more decidedly caudad. 



Vertex of head crossed by a short sharp sulcus which is deepest at in- 

 ferior end. Head clothed with numerous fine short hairs over vertex as 

 well as over frontal and more ventral region. Antennae similarly clothed 

 over entire length but more sparsely proximally. 



First dorsal plate about equal in width to head inclusive of mandibles. 

 Anterior margin widely convex, taken with anterior half of each lateral 

 margin semicircular, the median tooth of lateral margin at point farthest 

 laterad. Anterior margin bearing about 10 .setiferous tubercles which in- 

 crease in size laterad and pass gradually into the teeth of the lateral margin 

 which are 4 in number. In addition there are numerous similar tul)ercles 



