34 
General Remarks. 
The finds of Eocene insects from Europe, recorded on p. 7—9, 
however fragmentary and uncertain they are, serve to prove that beetles 
are the most frequently occurring finds, but it is of course impossible 
to draw any general conclusions from these finds on account of the 
small number of determinable and describable forms found. 
Through the investigations of Scudder and Cockerell the Rocky 
Mountain fauna, on the other hand, has become so well known that 
our conception of this fauna, obtained through an investigation of 
the systematic position of the forms, cannot be very wrong. From 
the Eocene of the Rocky Mountains we know as referred to species: 
1 Psocid. 
8 Odonates (-j- 1 only referred to genus). 
3 Trichoptera. 
6 Orthoptera (4- some not further referred). 
1 Aphid. 
43 Homoptera of which 28 Fulgorids. 
10 Bugs. 
3 Physopods. 
120 Beetles (+ some more or less undetermined) of which 76 weevils 
37 Nematocera (+ some undetermined) of which 12 craneflies. 
36 Flies (-f- some undetermined). 
18 Hymenoptera (+- some undetermined). 
286 species. 
The Rocky Mountain fauna thus appears to be characterized by 
its large amount of beetles; these insects make out half the number 
of species, arid the number of individuals in the single groups cor¬ 
responds rather well with the number of species within the same 
groups. It is, therefore, of interest to make a comparison with the 
Diatom-earth bed fauna of Denmark. It is true that the finds from the 
Diatom-earth bed are but few, only 35 specimens in all, so that they 
are in a much higher degree to be regarded as casual finds, but in 
spite of this a general view of the fauna is of interest. The Diatom- 
earth bed fauna consists of: 
Odonat 1 species (1 specimen). 
Lo.cust 1 species (1 specimen). 
Planipennia 2 (3?) species (3 specimens). 
Beetle 1 species (1 specimen). 
Hymenoptera 2 species (1 specimen of each). 
Undetermined Moths (5 specimens). 
Craneflies 4 species (1 specimen of each) -f- 2 not referred to species. 
Fly 1 species (1 specimen). 
Homoptera 5 species (1 specimen of each), all Fulgorids. 
Bugs, at least 8 species (3 referred to species, and at least 5 not refer¬ 
red to species) 15 specimens in all. 
