1910] Diplopoda from the Western States 251 



Polydesmus sastianus sp. nov. 



Dorsum brown; the carinae paler, yellowish. Sides pale brown. 

 Venter and legs yellow. Head light brown. Antennae light proxim- 

 ally, the distal joints brown. 



Head finely roughened. The vertex crossed with the usual im- 

 pressed line. Clothed rather densely with very fine short hairs. 



Antennae short. Clavately thickened. Distal articles sub-densely 

 clothed with moderately short hair ; but with only a few hairs on the first 

 and especially on the second articles. The four sense cones conspicuous. 



First dorsal scutum narrower than the head and also distinctly 

 narrower than the second segment. Transversely sub-elliptical with 

 the caudal margin, however, but little convex. Tubercles strongly 

 developed, conical, in crowded series. The setae conspicuous, those of 

 the rows of tubercles along cephalic and caudal margins very long and, 

 as usual, curved or hooked distally. 



Second segment not strongly bent forward laterally. The conical 

 tubercles strongly developed and densely arranged as on the first one. 

 Carinal margin with the anterior and the posterior angles about equally 

 rounded; laterally with six, large, angular, setigerous teeth, of which 

 the most cephalic, which is located on mesal side of cephalo-lateral 

 angle is smallest and most acute, the fourth and fifth with a secondary 

 indentation on their cephalic edge and three similar teeth on caudal 

 side. The series of teeth continued along the caudal edge of plate by 

 a row of large projecting tubercles. 



Third and fourth segments with their lateral margin shorter than 

 that of the second; the caudo-lateral angle of carina more rounded; 

 lateral margin with same number of teeth as the second. 



On the subsequent segments the caudo-lateral comers of the 

 carinae become more angular, first becoming sub-rectangular and then 

 on the last two preceding the anal plate a little produced caudad. 

 Entire dorsum with a longitudinal median keel-like elevation which is 

 better developed on the prozonites. Transverse sulci rather weak. 



Anal scutum strongly tuberculate, the tubercles conical and 

 setigerous like those of the preceding segments. Caudal process nar- 

 rowly rounded. 



Anal valves somewhat as in the preceding form. 



Anal scale sub-triangular. Caudal angle a little rounded. Seven 

 pairs of setigerous tubercles along the lateral margins. 



Most of the ventral plates are very distinctly marked both w^th 

 the transverse and with the longitudinal impressions; of these impres- 

 sions the longitudinal one is narrower and usually appears more sharply 

 impressed. 



Legs moderately clothed with rather short hair, the first two joints 

 more sparsely so. 



Length: 10-11 mm. Width 1.5 mm. Length of antenna ad 

 1.5-1.6 mm. 



Locality— Shasta Springs, Gal. (Aug., 1909.) 

 Three specimens were secured, one adult female and two 

 not fully grown males. 



