165 
the conclusion that the three principal insect localities in western 
Colorado and Wyoming are deposits in a single body of water, the 
ancient Gosiute Lake, as it was called by Clarence King; and 
in speaking of remains from these deposits as a whole, I have 
applied to them the term Goszute Mauna in distinction from the 
Florissant or Lacustrine Fauna in central Colorado. 
The result of the present studies upon the Tipulidz also has been 
to show that no single species of the Lacustrine fauna occurs in the 
Gosiute fauna, though the paucity of remains in the latter does not 
give this fact the same weight as in the Rhynchophora; and it 
should also be mentioned that among the few genera found in two 
of the localities in the Gosiute fauna, the species of each locality are 
distinct from those of the other. 
In his first extended communication on the amber Diptera, Loew 
called attention to the remarkable alliance of that fauna with the 
existing fauna of the eastern United States. He further expanded 
the subject in a most interesting essay, translated by Osten Sacken 
and published in S7/Zman’s Journal for 1864. In this paper he 
reached the conclusion that ‘‘ the amber Diptera stand in a much 
closer relation to the North American and to the European [Z. e¢., 
those now existing] than to those of any other fauna’’; and he 
further asserts ‘‘ with the utmost certainty that those among the 
living Diptera which most closely resemble the amber Diptera, 
abound in a most prevailing degree in North America and especially 
between the latitudes of about 32° to 40°.” 
Baron Osten Sacken, in numerous passages, has insisted upon the 
same resemblance. In the Tabular View of Tertiary Tipulide we 
have given further on, it will be seen that (omitting Tanymera as 
doubtful) thirteen genera are credited to the Baltic amber, of which 
ten are found in America, and one of them in North America only 
besides its occurrence in amber; this last is Idioplasta. On the 
other hand, only eight of the amber genera occur now in Europe, 
and all these genera have also American representatives. At the 
most, two genera, Trichoneura and Calobamon (and Tanymera 
also, if it is to be included), seem to be known so far only in amber, 
but they are all as yet imperfectly characterized. Only five of the 
amber genera have representatives elsewhere than in Europe or 
America, and one of these is cosmopolitan. 
No such striking conclusions can be reached from the study of the 
tertiary Tipulidee of North America, at least at present. A large 
