included in the genus Tropisternus. 109 



24. Hydrophilus sublcevis, Lee 



Lee., Proc. Ac. Phil., 1855, p. 368. 



Hydrophilus quadristriatus, Horn, Trans. Am. Ent. 

 Soc, 1871, p. 331. 



North America. 



This species appears to be closely allied to H. eali- 

 fornieus, but to be narrower and smaller, and with the 

 pubescent area at the base of the hind femur rather 

 larger ; the apical ventral segment has a strongly 

 elevated carina, the apex of which projects beyond the 

 extremity of the segment. There seems to be no sexual 

 difference in the sculpture of the mentum. In other 

 respects the species seems very similar to H. cali- 

 fomicus. 



I have seen only a pair of the species, so can form no 

 opinion as to its variation ; in both these individuals the 

 legs are nearly entirely pale yellow. 



25. Hydrophilus californicus, Lee. 

 Lee, Proc. Ac. Phil., 1855, p. 367. 

 North America (California). 



This species may be readily distinguished from H. 

 glaber by its less punctate upper surface, and by the last 

 ventral segment bearing only a carina or plica instead of 

 the spine existing in H. glaber. The systematic punc- 

 tures on the side of the prothorax form a somewhat 

 short and irregular line ; the sculpture of the epipleural 

 margin is distinct from the shoulder backwards. The 

 sternal spine is curved away from the body, and is elon- 

 gate, narrow, and deep, formed, in fact, as in H. glaber, 

 but scarcely so long and stout ; the apical ventral seg- 

 ment bears a plica or carina ; and the pubescent area 

 at the base of the hind femur is quite small. 



There is a striking sexual disparity in the sculpture of 

 the mentum and the lateral portions of the submentum, 

 the punctuation of these parts being much denser in the 

 male than in the female. 



The species is variable, and there may be more than 

 one mixed under the name. In one form there is a well- 

 marked development of coarse punctuation on the sides 



