288 
Psyche 
[September 
new subgenus Nemestrinopsis. It would seem, however, 
that he wished to retain R. sackeni Williston and R. sub- 
nitens Cockerell in Rhynchocephalus, proper, although this 
is not clear from his paper. 
The distinction between Rhynchocephalus and Neorhyn- 
chocephalus is entirely based upon two peculiarities of the 
venation. The first of these, viz., the development of the 
costa along the hind margin and its connection with the 
diagonal vein, is probably too slight and variable to be of 
generic value. At any rate, in some of the specimens of 
N. sackeni which I have examined, certain stretches of the 
hind margin are not visibly thickened into a vein, and the 
margin is not fully reached by the diagonal vein, the third 
and fifth posterior cells being incompletely divided. The 
second feature, viz., the contraction of the base of the fourth 
posterior cell, appears to be more reliable: it is present in 
40 specimens of Neorhynchocephalus, belonging to the four 
known species. As a rule, the cell is briefly stalked at the 
base; but sometimes it is narrowly sessile on the second 
basal cell. I have seen only one specimen in which it was 
narrowly sessile on the anal cell, but even this condition is 
very different from that of Rhynchocephalus tauscheri 
Fischer, in which the base of the fourth posterior cell 
touches the anal cell over a long stretch, its lower margin 
running nearly parallel with the lower margin of the discal 
cell. 
Contrary to Lichtwardt’s statement, the shape of the 
frons in the male is not of generic significance. He writes 
that in Neorhynchocephalus the eyes touch each other on 
the vertex in the male ; while the male of Rhynchocephalus 
has the eyes distinctly separated by the ocelli. In fact, the 
males of both genera have the eyes separated on the vertex 
itself by the ocellar triangle; below this the frons may be 
more or less narrowed. In N. volaticus and N. sackeni the 
frons is very much narrowed and linear, so that the eyes 
seem to touch each other. In two males of N. vitripennis 
(Wiedemann) the frons is moderately narrowed, the eyes 
being distinctly separated. 
1 The Zoological Record lists Neorhynchocephalus as dating from 
this 1910 paper; but the genus was validly established a year before. 
