152 PROCEEDINGS OF THE NATIONAL MUSEUM vol. in 



torynophor. We tentatively refer the species to Saussurobolus , a genus 

 of the Onychehnae, with the two other species from the highlands of 

 central Mexico. 



The original description of Arinolus torynophor is not detailed with 

 respect to the external characters, and the drawings of the gonopods 

 are quite small. We take this opportunity to publish a thorough 

 description of the species, and to provide a larger and more detailed 

 illustration of a posterior gonopod. For the other two species 

 treated here, we limit the description to points of difference from the 

 type species. 



Arinolus torynophor Chaniberlin 



Figure 10,a,b 

 Arinolus torynophor Chamberlin, 1940, p. 81, figs. a-c. — Loomis, 1950, p. 165. 



Holotype: Male, collection of R. V. Chamberlin, from Fish 

 Creek, 10 miles east of Tortilla Flat, Maricopa County, Arizona 

 (date and collector unknown) . 



Diagnosis: A large arinolid, up to 40 mm. in length and 3.5 mm. 

 in width in which the lateral ends of the coUum are produced caudo- 

 ventrad and extend below the level of second segment; the pleural 

 lobe of the second segment without distinct anterior marginal ridge; 

 sternites strongly trapezoidal in shape and with curved transverse 

 striae; mandibular stipes excavated for reception of antennae, the 

 ventral margin rounded but without marginal ridge ; terminal division 

 of telopodite of posterior gonopod large and elongate-oval, with a 

 very small solenomerite. 



Description (from topotype) : Male, about 38 mm. long and 3.4 

 mm. in diameter, with 44 segments. 



Color of preserved specimen light chestnut brown with the metazo- 

 nites dark bro\vn across dorsum; head, antennae, collum, legs, and 

 anal valves yellowish bro\vn. 



Body slender and parallel sided back to last foiu- or five segments, 

 which abruptly decrease in size. Collum and second segment slightly 

 wider than third to fifth, the sixth, and seventh segments also en- 

 larged slightly over normal body dimension. 



Head relatively large, width across mandibles as great as width of 

 collum, front slightly convex, very smooth and polished without 

 trace of transverse striations or genal grooves. Labral notch short 

 and rather deep; clypeal groove sharply defined and almost con- 

 tinuous with the distinct occipital gi"oove. Clypeal foveolae 4-4, 

 irregularly shaped and spaced. Antennae relatively long, extending 

 back to middle of second segment, the second article exceeding apex 

 of gena. Articles in decreasing order of length: 2, 3, 4, 5, 6, 1, 7, all 

 shghtly compressed and becoming increasingly setose distally, the 

 first three articles glabrous. Mandibular antennal depression very 



