Chamberlm — New Spiroboloid Diplopods. 169 



ing a narrow caudal border; anal valves dark. Sulcus of head narrowly 

 interrupted in frontal region. Clypeal foveolae 5+5. Collum as in 

 californicus; extending, in male, a little below level of second tergite. 

 Segments with a sharply impressed stria across dorsum just caudad of 

 covered region of prozonite much as in the preceding species. Surface 

 similar. Claw of first legs in male as long as last joint, that of the second 

 shorter. Number of segments, forty-two. 



Length (male), near 27 mm.; width, 3.25 mm. 



Locality. — California: Claremont (W. A. Hilton). 



Atopetholus fraternus, sp. nov. 



Easily separable from the two preceding species in the form of the 

 male gonopods. The telopodite of the anterior gonopods is bent con- 

 vexly forward at the side where it bears at the anterodistal angle a straight, 

 simple, process additional to the caudally directed one arising from the 

 distomesal edge behind, this feature at once separating it from the pre- 

 ceding species. The telopodites of the posterior pair proportionately 

 larger than in californicus but smaller than in parvus, crossing in the 

 middle line, rather broad, thin at the edges, concave above. Median 

 plate straight across distal end, much exceeded by the coxal plates. Color 

 dark olive gray with a deeper, black or dark olive annulus about the 

 caudal border, the extreme edge, however, pale. Antennae dark olive 

 to black Legs dark brown. Sulcus of head interrupted in frontal region. 

 Clypeal foveolae 5+5. Collum narrowed below as usual, the process 

 narrowly rounded; concave or excavated on caudal side just above lower 

 end and strongly concave in front opposite cardo as usual; margining 

 sulcus in front not extending dorsad fully to level of eye, diverging from 

 margin at upper end; surface subdensely finely punctate. Surface of 

 segments in general similar to that of collum. Each segment constricted, 

 the furrow rather wide, the pore lying in it and the suture at its caudal 

 edge. Suture curved at level of pore. First two pairs of legs in male 

 strongly thickened, their claws enlarged as usual; the third and fourth 

 pairs of intermediate thickness and their claws corrrespondingly inter- 

 mediate in size. Processes of coxae of third to seventh legs subconical, 

 smooth, those of the third pair largest. Number of segments, forty-one 

 or forty-two. 



Length (male), near 33 mm.; width, 4 mm. Width of female, 5 mm. 



Locality. — California: Friant. (R. V. Chamberlin.) 



Hesperolus, gen. nov. 



Resembling Onychelus and Atopetholus in general structure. Agrees with 

 the former and differs from the latter in lacking processes on the 

 coxae of the third and succeeding anterior legs in the male. Unlike 

 Onychelus the claws in the male are especially large on only the first 

 two pairs of legs, which are enlarged, the claws of the other anterior 

 legs of normal size, or those of the third pair a little more elongate. Differ- 



