314 CALIFORNIA ACADEMY OP' SCIENCES. 



CcELAMBUS MEDiAEis Lec. Texas, Arizona, south- 

 ern California. San Ignacio, Comondu and La Joya. 



Deronectes striatellus Lec. Colorado, 'Oregon, 

 California. San Francisquito. 



Copelatus Chevrolatii Aube. Oklahoma, Texas. 

 Baja California. 



Ilybiosoma regularis Lec. Southern California. La 

 Chuparosa. 



Eretes sticticus Lima. Almost cosmopolitan in dis- 

 tribution. Texas, Coahuila, Mexico, southern California. 

 Cabo San Lucas. 



Rhantus atricolor Aube. Texas, Arizona, Upper 

 Mexico. El Taste and San Francisquito. 



Rhantus flavogriseus Crotch. Idaho, California, 

 Arizona. Comondu and Guadalupe Island. 



Rhantus binotatus Harris. Widely distributed from 

 H. B. T. southward. San Esteban. 



Hydaticus stagnalis Fab. Very variable in colora- 

 tion. Illinois westward to Vancouver, thence southward 

 through California. San Jose del Cabo. 



Thermonectes marmoratus Hope. Texas, Arizona, 

 Mexico, Jalapa to Honduras. Cabo San Lucas and San 

 Jose del Cabo. 



Thermonectes peninsularis n. sp. San Jose del 

 Cabo. 



Megadytes fraternus Sharp. I have very little 

 doubt of the correctness of the reference of the peninsu- 

 lar specimens to this species. The males have the ante- 

 rior tarsi broadly dilated and without any large cupules; 

 the smaller cupules are arranged in two transverse series. 

 The female elytra are ormamented with closely-placed 



