140 PROCEEDINGS OF THE NATIONAL MUSEUM vol. in 



Discussion: The distribution of this genus appears to be centered 

 around the Colorado Desert of southern California and the arid region 

 of adjacent Baja California. Doubtless numerous species remain 

 to be discovered. One interesting inference to be made from the 

 recent contribution b}^ Loomis is that several species may occur at a 

 single locality, a form of sympatry apparently not developed in other 

 atopetholid genera. Not having material for personal examination, 

 we merely subjoin a list of the known species, most of which are well 

 described and nicely illustrated in Loomis' paper. 



Watichelus edentatiis Loomis 



Watichelus edentatus Loomis, 1949, p. 241, figs. 1, 2 (male holotype, USNM 



2514, from between San Diego and El Centro, San Diego County, California, 

 collected on January 29, 1921, by O. F. Cook), 



Watichelus etruirginatiis Loomis 



Watichelus emarginatus Loomis, 1949, p. 243, figs. 7, 8 (male holotype, USNM 



2515, from 8 miles south of Tia Juana, Baja California, Mexico, collected 

 on January 1, 1925, by O. F. Cook). 



Watichelus cooki Loomis 



Watichelus cooki Loomis, 1949, p. 243, figs. 5, 6 (male holotype, USNM 2516, 

 from Descanso, Baja California, Mexico, collected on January 1, 1931, by 

 O. F. Cook). 



Watichelus parallelus Loomis 



Watichelus parallelus Loomis, 1949, p. 244, figs. 9, 10 (male holotype, USNM 

 2513, from Chula Vista, San Diego County, California, collected in De- 

 cember 1921, by C. G. Marshall). 



Watichelus robustus Loomis 



Watichelus robustus Loomis, 1949, p. 241, figs. 3, 4 (male holotype, USNM 2512, 

 from Chula Vista, San Diego County, CaUfornia, collected on January 23, 

 1921, by O. F. Cook). 



Watichelus smithi (Chamberlin) 



Onychelus smithi Chamberhn, 1947b, p. 49, figs. 52, 53 (male holotype, Acad. 



Nat. Sci. Philadelphia 9971, from Murray Canyon, Colorado Desert, 3 miles 



north of Palm Springs, Riverside County, CaUfornia, collected in November 



1946 by Lloyd M. Smith). 

 Watichelus smithi Chamberhn, 1949, p. 169.— Loomis, 1949, p. 244.— Chamberlin 



and Hofifman, 1958, p. 159. 



Atopetholinae of uncertain generic position 



Atopetholus paroicus Chamberlin, 1941a, p. 7, fig. 5. 



Holotype: Female, collection of R. V. Chamberlin, from Moun- 

 tain Spring, San Diego County, California, collected on January 8, 

 1941, by Stanley and Dorothea Mulaik. 



