1908] 
Cockercll, Fossil Ccrcopiclcc (Homoptera). 
37 
ually join the media for a short distance — a condition approached 
in Lepyronia. 
The variabihty of the venation of the wings of the Cercopidce 
is undeniable, and it is of interest to note that the instabihty we 
find today existed as far back as the miocene. The color pattern 
of the tegmina really seems much more constant. In order to 
illustrate one more modification of the wing-venation, I give a 
diagram of the wing of a specimen of Tomaspis bicincta Say re- 
ceived from Mr. Heidemann. It will be 
seen that there are two little nervures leav- 
ing Cu-L, but breaking off without forming 
cross-nervures. It will also be noted in T. 
Fig. 3. Tomaspis hiciucta (and this is normal for the genus, 
bicincta Say. 
being just the same in the large Central 
American T. inca Guer.) Cug branches off from Cu^ at a 
large angle, though it is not afterwards bent as it is in Palec- 
phora. The figures accompanying this paper are pure diagram- 
matic, and are not intended to show specific minutiae. 
Taking the North American genera of Cercopidse, it is evident 
that as regards the venation Cercopis (Aphrophora) and Lepy- 
ronia stand at the foot of any phylogenetic tree, as being the most 
primitive. From Aphrophora or Cercopis we may readily derive 
Philmiiis, and from this we get two entirely diverse branches, 
one leading to Clastoptera, the other to Monecphora or Tomaspis. 
In Tomaspis we have a highly developed form, with the apical 
field of the tegmina densely reticulated and the color-pattern very 
different from that of Cercopis, namely two red or yellow cross- 
bars on a black ground. The beginnings of the Tomaspis pattern 
(with the divergence of the forks of the cubitus) are seen in the 
Florissant fossil Prinecphora balfeata Scudder; while an almost 
typical Tomaspis-p2ittevn is reached in the gigantic Petrolystra 
gigantea Scudder, the type of which I had the pleasure of examin- 
ing in the Scudder collection. 
