THE WATER SCAVENGER BEETLES. 253 



striae, fifth slightly elevated and. interrupted behind the middle; fourth ele- 

 vated opposite the break in fifth; the others almost uniform. Length 

 3.5 mm. 



Starke County; rare. August 20. 



487 ( -). HYDROCHUS GBANULATUS sp. uov. 



Elongate, slender. Above piceous with a greenish or olivaceous tinge ; 

 beneath piceous, legs dark reddish- or fuscous brown. Thorax a little 

 longer than wide, sides almost straight; surface, as well as that of head, 

 finely and very densely granulate-punctate, the fovea? very faint. Elytral 

 stria? wider than intervals, the latter very narrow, the fourth interrupted 

 behind the middle, fifth almost wholly wanting or not convex. Length 

 3.8-4 mm. 



Lake County; rare. April 29. An unnamed specimen is also 

 in the LeConte collection at Cambridge, labelled "Illinois." 



III. OCHTHEBIUS Leach. 1817. (Gr., "shore + to live.") 



Very small brown, black or piceous species having the thorax 

 narrowed at base, with a transparent side margin, and the disk with 

 impressed lines or fovea?, quite similar to those of Helophorus, but 

 interrupted. They occur in or about the edges of small pools and 

 woodland ponds ; also on the under side of stones in running water. 

 One undescribed species has been taken in the State, while three 

 described by LeConte have a range which may include Indiana, 



KEY TO INDIANA SPECIES OF OCIITIIEBIUS. 



a. Thorax abruptly sinuately narrowing from in front of middle to base 



and with a distinct angnlation at middle of sinuation, all the discal 



impressions well marked. FOVEICOLIJS. 



aa. Thorax abruptly sinuate from the middle, or more or less notched near 



the hind angles. 

 &. Thorax with well marked discal foveye. 



c. Form oblong-oval, subdepressed ; elytral punctures obsolete near 

 apex. NITIDUS. 



cc. Form short, broadly oval, strongly convex ; elytral punctures dis- 

 tinct to apex. 488. PUTNAMENSIS. 

 bl). Thorax without discal fovere, coarsely punctate, the lateral fovere 

 deep and broad. CEIBRICOLLIS. 



0. foveicollis Lee., 1.2-2.5 mm., 0. nit id us Lee., 1.8 mm., and 0. 

 cribricollis Lee., 2 mm. in length, all piceous-bronzed in hue, may 

 occur in northern Indiana. 



4SS ( -). Oeirmivmrs PUTNAMENSIS sp. nor. 



Short, oval, strongly convex. Elytra black, shining; head and thorax 

 bronzed ; legs reddish-brown. Thorax twice as wide as long, sides rounded 

 from apex to basal third, thence oblique and feebly sinuate to base; disk 



