36 TERTIARY COLEOPTERA OF NORTH AMERICA. 



scarcely rounded sides, smooth, and no sign of a median furrow. The 

 elytra are slender and elongated, parallel sided, smooth, but with some 

 signs of faint stria-; probably these are fainter than they would lie were 

 the}' not seen through the body, the under surface being exposed. 



Length of body, 4.(i mm.: of antenna'. 2 mm.: of elytra, 2.7f> mm.: 

 breadth of thorax, 1.1 mm.; of elytra, 1.6 mm. 



Florissant, Colorado: om- specimen, No. 6622. 



DYTISCID^E. 



The only fossils of this family in North America are two species in the 

 Pleistocene of Massachusetts and two in the older Tertiaries of Colorado, 

 each of the four belonging to a distinct genus. In the Old World, fifty-six 

 species have been found, belonging to seventeen genera, only two of them 

 represented among the American fossils, and these the older. Of these 

 species, twenty-seven, representing eleven genera, belong to the older 

 Tertiaries, and twenty-nine species of nine genera to the Pleistocene. Of 

 the Pleistocene species ten are recognized as still living. 



HYDROCANTHUS Say. 



This widely spread though restricted genus has lint a single living- 

 species in the United States, and no extinct forms are known except the one 

 here recorded. 



HYDROCANTHUS sp. 



I I,jil ><><< ,,ll, UK .sy/. Scudd.. Am. .lour. Sci. (3) XLVIII, lx:-5 (lx',14). 

 I 'eat of Xantucket, .Massachusetts. 



LACOOl'IIILrs Leach. 



Of this cosmopolitan genus, of which about a dozen North American 

 ^pecies are known, only two fossil species are recognized, the one here 

 recorded and one found by I leer in the Miocene of Spitzbcrgen. 



LA.CCOPHILUS sp. 



Laccopkilus /<. Scudd.. Hull. I'. S. (icol. (iroo-r. Surv. Terr.. II. Tx (IXTii); III. 

 Tr.lt (IxTT): Tcrl. In*. N. A.. 51T. pi. 5, li.i^. 11*:. 11T (LMKi). 



\Vhile li'ivei-, < 'olorado. 



