8 TERTIARY RHYNCHOPHOROUS COLEOPTERA. 
Relative abundance of the orders of insects in different western deposits. 
Number of specimens. {ee Percentages. 
Orders. ae = 3 
Alllocal-| Floris- | Other lo-| Afllocgl-| Floris- | Other lo- 
= ities. sant. calities. | ities. sant. calities. 
Hymenoptera ..0.2.-.2-..-<:2------ 277 243 | 34| 15.2 34.5 3.0 
Diptera mass... eee ne eee eee 432 184 248 | 23.7 26.1 22.2 
@oldoptern sesso se eee eee eee 806 104 702 | 44.3 14.8 63.0 
Hemiptera. 9. -es sao se ee ene 185 86 99 10.0 12.2 8.9 
Orthopterasscc te ee 19 | g 1 | 1.0 0.3 1.5 
Wentop LOlkee cesses are eee 90 | 75 15 | 5.0 10.6 1.3 
Apnolinila, “Css 5-2 oes tee | 11 | Tift ee ree | 0.6 5 \ 
Pocalie ei ce see Fe ee eee oem 1, 820 | 705 1,115 | 99.8 100. 0 99.9 
— a a = —— = all 
Now, When we come to examine the species of Rhynchophora, we 
shall find that while the three localities in western Colorado and Wyoming 
share a number of forms in common, not a single species found at Floris- 
sant occurs in either of the others. To give the precise figures: From 
Florissant 116 species have been obtained ; from the Roan mountains 40, 
of which it shares 6 with Green river and 7 with White river, besides 6 
others common to all three localities, together nearly half its fauna (19 sp.); 
from the White river 23 species, of which it shares 2 with Green river and 
7 with the Roan mountains, besides the 6 common to all, or nearly two- 
thirds its fauna (15 sp.); and from Green river 39 species, of which it 
shares 2 with White river and 6 with the Roan mountains, besides the 6 
common to all, or more than one-third its fauna (14 sp.). These facts, with 
the field evidence, appear to show that the three principal localities in west- 
ern Colorado and Wyoming are deposits in a single body of water, the an- 
cient Gosiute lake, as it was called by King. The absolute separation, 
in specific forms, between the fauna of these deposits and that of Florissant 
must be indicative of a distinction greater than that of mere geographical 
position, for the Roan mountains are about equally distant from Green 
river and Florissant. It is clearly an indication of a difference in age, 
though they have usually been regarded as occupying similar horizons. In 
the following pages I have referred to the species regarded as belonging to 
the Gosiute lake as the Gosturr FAUNA whenever it has been desirable to 
speak of them in common; and in contrast I have ealled the fauna of Flo- 
