3l8 CALIFORNIA ACADEMY OF SCIENCES. 



ora. My specimens vary in this respect: the spines may 

 be present or not, or there ma}'^ be one or two on one 

 femur and none on the other. The difference between 

 Belonuchus and Philonthus is at most very shght. Oc- 

 curs in Arizona and northern Mexico. Cabo San Lucas 

 and San Francisquito. 



Philonthus flavolimbatus Erichs. Gulf States, 

 Arizona. Cabo San Lucas. 



Philonthus politus I^inn. ( cr/icus Rossi). Abundant 

 in Europe and Boreal America. San Jose del Cabo. 



Philonthus instabilis Horn. Wyoming, Colorado, 

 Utah, Mojave, Cal. La Chuparosa. 



Philonthus alumnus Erichs. In its different vari- 

 eties distributed on the Atlantic and Gulf regions, An- 

 tilles, Mexico, Texas, iVrizona. San Jose del Cabo. 



Philonthus quadrulus Horn. Arizona. Cabo San 

 Lucas. 



AcTOBius Py^DEROiDEs Lcc. Utah, Texas, California, 

 Arizona. San Jose del Cabo. 



AcTOBius ELEGANTULUS Hom. Southern California, 

 Arizona. Cabo San Lucas. 



Cafius sulcicollis Lee. Southern California, near 

 San Diego. Magdalena Island. 



Cafius opacus Lee. Southern California, sea coast. 

 Baja California (LeConte.) 



Xantholinus cephalus Say. Canada to Washington, 

 Nevada, Colorado, Utah, California. San Julio. 



Stenus luculentus Cas. Stockton, Cal. La Chup- 

 arosa. 



Cryptobium arizonense Horn. Tucson, Ariz. San 

 Esteban. 



