188 
which may be regarded as tribes, the relative importance of which 
in recent and ancient times has been pointed out in a preceding 
table, from which it will appear that every one of them has been 
recognized among the fossils. 
The Limnobini take precedence as they do among modern types, 
while the Rhamphidini (in Europe in amber only), the Eriopterini, 
and Limnophilini follow in numbers, the remaining groups being of 
least importance and three of them altogether lacking in American 
deposits; while the Cylindrotomini, the only remaining tribe ap- 
pearing in America, is lacking in the European tertiaries. The Ani- 
somerini are represented in Europe by three species of Eriocera 
in amber, the Amalopini by four species of Ula in amber, and the 
Ptychopterini by a single species of Idioplasta in the same and by 
a Ptychoptera at Krottensee. It thus appears that with the excep- 
tion of the Ptychopterini all the tribes represented in the European 
rock deposits occur also in America, while America is also. well 
represented in the tribes Rhamphidini and Cylindrotomini. The 
American genus Pronophlebia cannot yet be placed. 
Especially difficult of determination among the Limnobini has 
been. the position or the absence of the subcostal and marginal 
cross veins, which play so important a part in the arrangement and 
distinction of the genera. It is by no means impossible that in 
some instances I may have erred in my interpretation of marks 
upon the stones, but I have endeavored to give all points a rigid 
scrutiny. It is certainly here that errors are most likely to have 
been made. : 
Nearly one hundred additional specimens from Florissant, more 
or less imperfect, but certainly belonging to this subfamily, await 
study ; and I may add that there is a specimen in the collection of 
the U. S. Geological Survey (No. 1470) which represents an inter- 
esting new genus falling near Atarba with distinct tibial spurs, but 
which I refrain from characterizing here, as I can give now no 
illustration of it. 
As the number of genera in no one of the tribes exceeds three, 
I have thought it best to include all the genera of the subfamily in 
one table, as follows: 
