alone but in individuals. A second anomaly is noticed in the abun- 

 dance of Byrrliidae, a northern characteristic in America nowa- 

 days, and a third is the very pronounced paucity of Chrysomeli- 

 dae. Light may be thrown upon some of these problems when 

 the Tertiary Coleopterous fauna of this country has been fully 

 investigated. For the moment, all that can be done is to call 

 attention to these phenomena, leaving their explanation to a 

 fuller knowledge. 



Because of the apparently close generic correspondence of 

 the fossil beetles with species now living in North America, I am 

 forced to belieA'e that the insects of the Florissant Miocene stand 

 in direct ancestral relationship to our present fauna, or that at 

 worst they are closely collateral branches from a common stem. 

 In most instances where the fossils are compared with modern 

 forms, the specific affinities and the facies seem to be distinct- 

 ively North American rather than European or Eurasiatic. It 

 is presumable that North America received a large proportion 

 of the species now inhabiting that part of the continent above 

 the Sonoran zones from the Eurasian lands in some far distant 

 time. It also seems likely that these immigrants would diverge 

 more from the parental stock than those which remained in the 

 original habitat. The Florissant fauna is sufficiently like the 

 Eurasian of today to indicate a common general origin, but it 

 is even more like that of recent North America and I see, 

 at present, no reason to believe that it had been eradicated in 

 anything like entirety, to be replaced by members of a fresh in- 

 vasion from the north. The presence of a considerable number 

 of southern types may be explained on the principle of an in- 

 jection from centers of dispersal lying in that direction, or it is 

 possible that they represent the remnants of a still more ancient 

 fauna, occupying the Florissant site previous to the irruption 

 of the Eurasian wave which gave the insect life its characteristic 

 tinge. 



^lost of the specimens described in this article were collected 

 by myself on the Wilson ranch, near Florissant, and the types, 

 in such cases, are in my collection. AYhere another source or 

 disposition holds, it is so indicated. All the figures are from 

 my own camera lucida drawings on scales to suit the size or 



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