II4 NATURAL HISTORY BULLETIN. 



DYTISCIDA 



Laccophilus maculosus Germ. Occasional, in sloughs. 

 Abundant northward, over the Atlantic slope. 



L. americanus Aube. Very common in ponds and sloughs 

 during June and July. Contained also in Townsend's collec- 

 tion. 



Bidessus pullus Lee. Common throughout June and July, 

 in resacas. Also known from Louisiana and Mississippi. 



Coptotomus interrogatus Fabr. Not common. Found 

 in sloughs, during July. West to California, north to Canada, 

 east to Atlantic coast. 



Copelatus chevrolatii Aube. Inhabits the resacas about 

 Brownsville, but is not plentiful. June and July. Recorded 

 from Lake Superior, Kansas, New Mexico, Arizona and Cali- 

 fornia. 



Eretes sticticus Linn. One specimen sent by Armstrong, 

 dated September. Europe, Asia, Africa, Oceanica, South 

 America. In the United States it is known from Kansas, New 

 Mexico and California. 



Thermonectes ornaticollis Aube. Abundant in Sep- 

 tember, (Armstrong). Pennsylvania, Illinois, Kansas, New 

 Mexico, (Albuquerque), Arizona and Mexico. 



HYDROPHILID^. 



Hydrochus varioeatus Lee. Common in resacas, near 

 the bank. June and July. A specimen of this genus, in bad 

 condition, is among the material sent by Townsend. The 

 identification is due to Dr. Horn. Originally described from 

 San Diego, California. 



Ochthebius nitidus Lee. Common at Brownsville, same 

 time and place as the preceding. Known from Lake Superior, 

 Fort Yuma and Oregon. 



Hydrophilus triangularis Say. September, (Armstrong). 

 Abundant over the greater part of the United States, from the 

 Atlantic to the Pacific, extending also into Canada and Mexico. 



