Scudder.] 
566 
[April 2, 
with the possible exception of the Jassides, the variety and abun- 
dance of forms are greater in America than in Europe, even includ- 
ing the types from amber, while a comparison of the rock deposits 
alone would show avast preponderance on the American side. In the 
number of individuals the Cercopidae easily hold the first rank, and 
this appears to be true in Europe as in America ; next follow the 
Aphides, for which in variety of type and in interest America far 
excels. The Jassides appear to present relatively the least interest, 
but the absence from American deposits of one whole division of 
that family, the Membracida, is rather surprising in view of their 
presence (though rarely) in European deposits and their relative 
abundance in America to-day. 
The following tabular enumeration of the species and genera oc- 
curring in European and American tertiaries may serve to present 
in a clearer light the agreements and disparities between them. It 
should be remarked, however, that the European list is drawn from 
miscellaneous sources and includes all those genera and species 
which have been merely indicated as occurring in certain deposits 
and might fairly be considerably reduced. It should not be over- 
looked, moreover, that it includes all the amber forms. 
TABLE II. SUMMARY LIST OF KNOWN FOSSIL HOMOPTERA. 
FAMILIES. 
AMERICA. 
EUROPE. 
GENERA. 
SPECIES. 
GENERA. 
SPECIES. 
(Joccidse 
1 
1 
6 
9 
Aphides 
15 
32 
4 
20 
Psyllidse 
2 
2 
0 
0 
Fulgorina 
16 
29 
7 
18 
Jassides 
11 
21 
9 
24 
Cercopidse 
10 
27 
4 
24 
Stridulantia 
0 
0 
1 
7 
Totals. 
55 
112 
31 
102 
If we exclude the amber forms and compare the fauna of the rocks 
only, we shall reach a very different result, as the following table 
will show. 
