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considerably shorter than the rest of the vein, which terminates 
above the apex of the wing. The third longitudinal vein arises 
from the second a little before the tip of the auxiliary vein and is 
met by the short cross vein at a distance from its origin equal to the 
length of the short cross vein. The space between the third longi- 
tudinal vein and the upper branch of the fourth longitudinal vein, 
normally—and so far as I am aware invariably—open in all Limno- 
binze, is here closed about half way to the tip of the wing (varying 
in different species) by a cross vein, from which springs an inter- 
calary vein, thus doubling the upper posterior cell at the apex and 
forming of its basal portion a supernumerary discal cell, essentially a 
counterpart of the normal discal cell and overlying it; it would 
seem to be formed by a mesial forking of the third longitudinal 
vein, and the base of the fork then connected by a cross vein to 
the uppermost branch of the fourth longitudinal vein. Both discal 
cells are usually very elongate (least so in the species upon which 
the genus was founded), the upper, or supernumerary, usually the 
longer and narrower, though they are subequal in length. There 
are five posterior cells and the great cross vein strikes the fourth 
longitudinal vein at the discal cell close to the base of the latter. 
The fifth longitudinal vein is very gently arcuate beyond this cross 
vein, while the sixth and seventh are straight throughout, the latter, 
however, arcuate at the extreme tip and almost reaching the middle 
of the wing. The legs are long and slender and the tibiz without 
spurs at the tip. 
This genus was well developed in the American oligocene, especi- 
ally in the White River basin, where it seems to include the larger 
number of species of Limnobinz. I leave their description, how- 
ever, to another occasion and characterize at this time only the 
species found at Florissant, none of which appear to be identical 
with those from the White River basin. The genus does not ap- 
pear to be found among the European fossil Limnobinz heretofore 
published. 
This genus, it seems to me with little doubt, must fall into the 
Cylindrotomini, although the tibiz lack spurs. I am forced to this 
conclusion by the close resemblance of the neuration to that of 
Cylindrotoma and Liogma, notwithstanding the striking differences. 
Especially the formation of the marginal cell is essentially the same, 
while the absence of the anterior cross veins and the general be- 
havior of the auxiliary vein sustain this view. It seems to me very 
