COLEOPTERA OF SOUTHERN CALIFORNIA. 55 



Gyrinus. G. plicifer occurs in the small streams of 

 the mountains and foot-hills, while consobrinus generally 

 prefers larger and more permanent waters; the former 

 is not rare about San Francisco, more especially in the 

 small streams of the redwood region, a few miles north 

 of the Bay; the latter extends its range into Oregon. I 

 have seen hundreds of consobrinus about the electric 

 lights at Riverside, in May. Le Conte mentions having 

 two examples of affinis from middle California, and I 

 have a species of doubtful identity from the middle 

 Sierras. 



Gyretes. G. sinuatus, occurs at Yuma (Le Conte). 



HYDROPHILID^E. 



Helophorus. H. obscurus, common and widely dif- 

 fused: species doubtful, one example, Ventura, March: 

 fortiSj San Francisco (Le Conte): angustulus, northern. 



Hydrochus. Undescribed species, Ojai Valley, March; 

 San Bernardino Mountains, July; rare: variolatus, San 

 Diego (Le Conte): vagus, Colorado River. 



Ochthebius. The species occur sometimes in great 

 numbers in the mud or silt or under stones in the shal- 

 low water of the margins of streams or pools, where any 

 agitation of the bottom brings them to the surface, upon 

 which they float and are easily taken. 0. rectus is our 

 commonest species and occurs nearly everywhere; I 

 have taken it plentifully in muddy irrigating ditches at 

 Riverside, in clear streams, and at San Diego on a salt 

 marsh which is covered by tide-water: interruptus , 

 Riverside, San Diego, Redondo; common at the latter 

 place, living in algse in a small lake much salter than 

 the ocean: discretus, widely diffused and moderately 

 common: puncticollis, rare, San Bernardino Mountains, 

 Ojai Valley: sculptus, rare, Ventura: costipennis, one 



