170 Proceedings of the Biological Society of Washington. 



ing from both the genera mentioned in the greater simplicity and reduction 

 of the telopodite of posterior gonopods, which is very short, distally 

 rounded, not blade-like and not strongly chitinized. The anterior median 

 plate distally broad much as in Atopetholus but extending farther distad. 

 Coxal pieces of anterior gonopods broad, without processes. Telopodite 

 of anterior gonopods distinctly articulated; narrowed distally into a short, 

 distally rounded but not expanded process which lies in the general plane 

 of the plate, not extending caudad from it as in Atopetholus. 

 Genotype, H. wheeleri, sp. no v. 



Hesperolus wheeleri, sp. nov. 



A species much smaller than those known in Atopetholus and Onychelus 

 excepting 0. hospes, an Arizonan species. From that species, aside from 

 generic differences evident in the male, distinguishable in having the 

 repugnatorial pore in front of the constricting furrow of the segment, 

 not behind it. General color brown, the caudal borders and covered part 

 of segments fulvous. Above level of pore on prozonite of each segment a 

 large spot formed by small fulvous areas, a similar areolation of the pro- 

 zonite in its anterior part down the sides. Anal scutum and valves dark 

 excepting a narrow caudal border. Collum with black anterior and 

 posterior bordering bands united below on each side. Head with a net- 

 work of dark lines excepting a black area in frontal region, which sends a 

 branch to each eye and bifurcates below. Clypeal foveolae 5+5. Sulcus 

 of head widely interrupted in the frontal region. Antennae slender, the 

 second article but little exceeding the third in length. Collum with 

 anterior margin incurved opposite each cardo; lower angle or process 

 curved back a little distance over the second segment, the posterior margin 

 just above it being concave. Segments constricted caudad of middle, 

 the furrows pronounced. Surface of segments in general smooth, punctate 

 at most few and very vague. Anal valves broadly rounded, the mesal 

 edges meeting in a pronounced groove. The coxal plate of anterior 

 gonopods with distal margin nearly straight, its distomesal corner a little 

 elevated, rounded; exceeding the median plate a little. Number of 

 segments, forty. 



Length (male), about 24 mm.; width, 2.8 mm. 



Locality. — California: Santa Ynez Mountains, Cold Spring Canyon. 

 (W. M. Wheeler). 



