454 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
in length with distinct, simple, impunctate striae. It is possible that 
more than one species is included in the material but there seems to 
be no sure means of separation with the specimens at hand. 
ATAENIUS RESTRUCTUS Wickham. 
Three specimens, No. 2,536-2,538 M. C. Z. (No. 2,471, 2,502, 
11,298 S. H. Scudder Coll.). They agree with my type in size and 
form and I think it best to assume their identity, although in some 
lights the elytral striae seem to show signs of punctures. The speci- 
men bearing Scudder’s number 2,502 exhibits the hind tibiae very 
nicely and from the slender structure of these parts and the lack of 
distinct transverse ridges it seems wise to assign the species to Ataenius, 
though I had first described it as an Aphodius. 
ApuHoptius Illiger. 
The removal of my A. restructus to the genus Ataenius leaves six 
described species of Aphodius from the Florissant shales. Two new 
ones are found in the present collection, both readily distinguishable 
from those previously known. While mammal remains are practi- 
cally unknown at Florissant, it is probable that the region adjacent to 
the old lake was well populated with the numerous ungulate and other 
types of mammals known to abound during the Tertiary times. It is 
a matter of common knowledge that some of the species of recent co- 
prophagous Scarabaeidae select the dung of one or more species of 
mammal as food, in place of promiscuous feeding. Putting together 
the known abundance of ungulates"in the Tertiary period and the 
selective habit of dung-eating beetles, it is reasonable to assume 
that the great specific development in Aphodius at Florissant was 
correlated with a plentiful supply of mammalian dung of different 
kinds. It appears to me likely that a good many of these old Aphodii 
became extinct along with the mammals that formed the sources of 
their food supply. All of these Florissant fossil Aphodii belong to the 
division of the genus with short scutellum — the same section that is 
most abundant in North America today. None of them are espe- 
cially peculiar in any way, though their specific characters are well 
marked. Some of them must have occurred in considerable numbers 
if we may judge by the frequency of their remains in the shales. 
Pe 
