1956] 
Adams — Chrysopidae 
71 
Paleochrysa, which is otherwise the most primitive de- 
scribed genus, has the quadrangular first intra-median 
cell characteristic of more advanced genera such as 
Nothochrysa. On the other hand, the occurence of an 
intra-median cell formed as in Pimachrysa, Triplochrysa, 
and Dictyochrysa, in such widely separated areas as 
North America and Australia, would seem to indicate 
that the basal position of the second medio-cubital cross- 
vein was broadly distributed in the past. It is entirely 
possible that the basal position has been secondarily 
derived; however, the simple bifurcate condition of MP 
found in these genera certainly appears to represent the 
more primitive situation. Paleochrysa, Nothochrysa, et 
al., may then be representative of steps that have occurred 
in the evolution of more advanced genera, which possess 
a triangular cell, derived from the quadrangular first 
intra-median cell by fusion of MP 1 + 2 and MP 3 + 4. 
The apex of this type of triangle is directed apicad, not 
basad as is that of Pimachrysa. In Hypochrysa, since 
MP 3 + 4 fuses with MP 1 + 2 as in Chrysopa, the basal 
position of the cross-vein is presumably secondarily derived. 
The first medio-cubital cross-vein of the fore wing is 
a remnant of a prominent medio-cubital y-vein, and is 
present in all recent Planipennia. Its absence from several 
of Carpenter’s drawings of the Miocene genera seemed 
significant when viewed in the light of Kimmins’ specula- 
tion (1952b) that, in the Apochrysinae, the cross-vein 
found replacing it in its usual position represents instead 
the remnant of MP 3 + 4. An examination of the fossils 
used in the preparation of these drawings demonstrated, 
however, that this cross-vein is present in all three of 
the Miocene genera, and is located in its usual place, 
opposite the cubital fork. 
The subcostal cross-vein has been omitted in Carpenter’s 
drawings, with the exception of Figure 2 ( Paleochrysa 
fracta), in which it should be located slightly distad of 
the first radial cross-vein, instead of where shown. In 
Paleochrysa, this cross-vein is always located approxi- 
mately opposite the first radial cross-vein; in Trihochrysa 
