46 TERTIARY COLEOPTERA OF NORTH AMERICA. 



the sides arcuate, the angles obtuse, the disk apparently almost smooth, but 

 very faintly and delicately punctate. Middle tibiae slender and equal, much 

 smaller than the apex of the femora. Elytra together but little longer than 

 broad, somewhat wider than the thorax, the sides somewhat arcuate, the sur- 

 face delicately, not very deeply, striate, with regular very elongate impres- 

 sions; interstitial spaces apparently sericeous. 



Length, 8 mm.; breadth, 4.1 mm.; length of antennas, 2.1 mm.; of 

 thorax, 1.5 mm.; of elytra, 4.9 mm. 



Florissant, Colorado; one specimen. No. 12039. 



One hundi-ed and thirteen fossil species of Staphylinidae are known or 

 indicated, sixty -five from the Old World, forty-eight from the New. Tliese 

 are almost entirely from the older Tertiaries, only seven species, all extinct, 

 being known from the Pleistocene, two from Europe, five from America; 

 besides these a number of other forms from the Canadian Pleistocene still 

 await study. -^ These fossil species have been referred to forty-two genera, 

 of which four are regarded as extinct, three in the Old World, one in the 

 New. Twenty-five of these genera are found in America, twenty-nine in 

 the Old World, twelve occurring in both. Only two genera, one on each 

 continent, have been found in the Pleistocene and not in the older Tertiaries. 



One of the peculiarities of the Florissant Staphylinidse as compared 

 with living forms is the prevalence of species with short antennae. This is 

 most marked in cases where the species, living and extinct, of the same 

 genus are compared, and being nearly universal can hardly be referred to 

 their being in some cases only partiall}^ exposed in the fossils, since in very 

 many all the joints can be seen, and the peculiarity still holds true. The 

 same thing is true in perhaps equal degree with the legs, which in the fossil 

 species are almost invariably shorter than in their modern representatives. 



HOMALOTA Mannerheim. 



This dominant genus is mainly north temperate and numerous species 

 occur in the United States. The species here recorded is the only one 

 known as fossil. 



^ These have now been studied and will soon be published by the Geological Survey of Canada. 



