ART. 8. MILLIPEDS OF CENTRAL AMERICA CHAMBERLIN. 51 



SCHISTIDES, new genus. 



Composed of head and twenty segments. Head with a distinct 

 sulcus across vertex. Antennae long, not much increasing in thick- 

 ness distad ; the second to sixth articles long, not much differing in 

 length, Collum semicircular, the anterior margin more straight in 

 middle region than laterally; anterior corners of keels rounded, the 

 caudal corners acute; nearly as wide as second tergite; setiferous. 

 Keels of the following tergites produced caudad, as in TricTwmorpha. 

 Also the tergites are similarly impressed with deep transverse sulcus, 

 behind which are typically two series of tubercles. Sternites in male 

 without processes. Anal tergite triangular, truncate at tip. Anal 

 scale somewhat triangular, acute, behind, the sides convex. Legs 

 slender. None of them modified in the male. No tarsal pads. 



In the gonopods of male the coxa is thick and cylindrical. In 

 the telopodite the femur is distinctly separated, narrow, the mesal 

 side with a pit lined with hairs. Tibia deeply divided into two 

 branches of which the dorsal (caudal) is broader and more plate-like 

 and curves about the other distally ; the ventral or anterior division 

 expanded into more lamellar form distally and giving rise at distal 

 end to a slender style which in the genotype is geniculate. 



Genotype. — Schistides atopophallus^ new species. 



In general structure nearest Trichomorpha^ but differing es- 

 pecial in the characters of the gonopods, such as in the distinct seg- 

 mentation of the telopodite, the narrow femur, the deeper division 

 of the tibia, the different seminiferous process, etc. Also differing 

 in lacking any secondary modifications of the legs and sternites of 

 the male. 



126. SCHISTIDES ATOPOPHALLUS, new species. 



Plate 19, figs. 4-9. 



Dorsum chocolate brown or almost black, the caudal angles of the 

 keels yellow. Antennae chocolate brown. Legs brownish yellow. 

 Dorsum weakly arched. Keels high, a little bent upward. Posterior 

 angles of keels stronglj^ produced, the processes becoming longer in 

 the posterior region, the ends not at all curved. Anterior angles of 

 keels rounded. On second, third, and fourth keels the outer margin 

 presents a small anterior tooth followed by two larger teeth or cre- 

 nations. On the pore-bearing keels there is but one distinct marginal 

 tooth, this large and immediately in front of porigerous thickening. 

 In the nonpore-bearing keels caudad of the fourth there are mostly 

 only two serrations or crenations, the third being obsolete (pi. 19, 

 fig. 5). Dorsal surface of prozonites wholly smooth. Metazonites 

 with a deep transverse sulcus, behind which there are two rows of 



