251 FAMILY VI. — HYDROPHILIDJE. 



finely and sparsely punctate, its sides broadly flattened; median groove 

 wide and deep, discal fovea? separated, the hind ones oblique and larger 

 than those in front: lateral ones broad, shallow and but slightly curved. 

 Elytra with rows of large quadrate punctures. Length 1.5 mm. 



Putnam County; rare. October 17. Sifted from debris at side 

 of hillside spring. Mr. Blanchard. who compared the specimen 

 with those at Cambridge, writes that '"the short convex form is 

 quite different from any of our named species." 



IV. Hydr.exa Kug. 1794. (Gr.. ' k 'to wash or bathe.") 



Our single member of this genus is smaller than any of those 

 belonging to the two preceding genera. The thorax is subquadrate. 

 about three-fourths the width of elytra, and the latter are marked 

 with more than ten rows of punctures. 



489 (15S2). Hydjr/ena PENNSYLVANIA Ivies., Linn. Entom.. IV, 1846, 16G. 



Elongate-oblong, subconvex. Piceous or dark reddish-brown, the palpi, 

 legs and narrow side margins of thorax dull yellow. Thorax narrower at 

 base than apex, side margins sinuate ; disk coarsely and densely punctate 

 and with a large impression each side near front angles. Punctures of ely- 

 tral striae close, rather coarse, quadrate ; intervals narrow, convex. Length 

 1.8-2.2 mm. 



Kosciusko County; scarce. June 21. Sifted from damp, de- 

 caying sphagnum moss in tamarack swamp. 



Tribe II. IIYDROPLTILIXI. 



Large or medium-sized beetles of an oval or elliptical convex 

 form, olive-black in color, rarely with sides of thorax and elytra 

 yellow. Elytra not striate; antenna^ 9-jointed; meso- and meta- 

 sterna forming a continuous keel which is prolonged behind into an 

 acute spine : middle and hind tarsi strongly compressed, fringed on 

 the inner side with long hairs. Three genera occur in Indiana. 



KEY TO GEXERA OF HYDROPHILIXE 



a. Prosternum sulcate ; metasternal spine long. 



lj. Length 25 or more mm. : last joint of maxillary palpi shorter than 

 the preceding. Y. Hydrophiles. 



66. Length less than 12 mm. : last joint of maxillary palpi equal to or 

 longer than preceding. VI. Tkopisternijs. 



aa. Prosternum carinate; metasternal spine short: length 13-16 mm. 



VII. Hydrocharis. 



V. Hydrophilus Geoff. 1764. (Gr., " water + loving. ") 



This genus includes two very large black beetles, the giants of 

 the family as represented in North America. 



