Seudder.] 
564 
[April 2, 
cal area of our tertiary fossils), the Homoptera hold a still more 
insignificant place, forming scarcely more than thirteen per cent 
of the whole. In tropical countries a very different proportion ob- 
tains, the Homoptera holding or nearly holding their own beside 
the Heteroptera, and subtropical countries or those which feel the 
direct influence of their proximity show an intermediate position. 
Thus, in Berg’s “Enumeration of the Argentine Hemiptera,” the 
proportion of the Homoptera to the whole is almost exactly thirty 
per cent. Now, it is precisely this proportion, 40 : 93, or thirty 
per cent, which Heer found the fossil Homoptera to hold in his first 
essay on the fossil Hemiptera of Oeningen and Radoboj ; and 
a careful enumeration of the fossil Hemiptera of Europe to-day 
gives the Homoptera thirty-four per cent of the whole fauna ; or, if 
those from the amber (which greatly heighten the proportion of 
Homoptera) be excluded, and we reckon those of the rocks only, 
the Homoptera have twenty-seven per cent. On the other hand, if 
we take only the fauna of the oligocene of Europe, including the 
amber, the proportion of the Homoptera amounts to forty-one per 
cent. This clearly indicates an approach to tropical relations the 
further back we go. Our own tertiary fauna is almost exclusively 
oligocene and has been found in a multitude of minor points to 
show distinct tropical characteristics, and it therefore becomes of 
peculiar interest to learn the numerical relation herein of the Ho- 
moptera to the Heteroptera ; now here, much as in the oligocene 
of Europe, we find the Homoptera claiming forty per cent of the 
whole hemipterous fauna. The significance of these figures can 
hardly be doubted. 
Before passing to a separate consideration of the two subor- 
ders, it may be well to make a single statement or two applicable 
to both. 
1. The general facies of the hemipterous fauna is American, and 
distinctly more southern than its geographical position would indi- 
cate. 
2. All the species are extinct, and though the localities at whfch 
they have been found are few, many of them near together and all 
or nearly all presumably oligocene, yet there is scarcely an in- 
stance where the same species occurs in two localities. 
3. No species are identical with any European tertiary forms. 
4. So, too, a very considerable number of genera are extinct, 
f 
