Scudder.] 
408 
[February 22, 
Baltic, in having no transverse series of regular discoidal areoles 
below the pterostigma. A single species of Osmylus represents 
the Hemerobidae, and differs from living forms, as does also the 
amber species, in the simple character of the costal nervules, the 
much smaller number of sectors, and the limited supply of cross 
veins in the basal half of the wing, giving this region a very dif- 
ferent appearance from its rather close reticulation in modern 
types. It may here be noticed that as a very general rule the 
neuration of the wing is much closer in modern Planipennia than 
in their tertiary representatives. 
There are four species of Chrysopidae, referable to two gen- 
era, each of them extinct ; Chysopidae have not before been rec- 
ognized in tertiary strata, the single species poorly figured by 
Andra, and never carefully studied, being much more probably 
one of the Hemerobidae. These two genera, called Palaeochrysa 
and Tribochrysa, are allied to the living ISTothochrysa, but differ 
from modern types in the zigzag course of the upper cubital 
vein, and in its direction, which is through the middle of the 
wing, as w T ell as by the smaller number of sectors and the entire 
absence of any transverse series of gradate veinlets ; Palaeochrysa 
is represented by a single species, Tribochrysa by three, and 
the genera differ from each other in the course of the upper cub- 
ital vein, which in Palaeochrysa is direct and bordered by com- 
paratively uniform cells, while in Tribochrysa it is doubly bent in 
the middle and is therefore bordered by very unequal cells. The 
single species of Panorpidae, referable to a new genus, Holcorpa, 
has already been described 1 under the name of H. maculosa. 
It differs from Panorpa in the entire absence of cross veins, and 
is remarkable for the spots on the wings. No planipennian Neurop- 
tera have been found in the Green River shales, but the tertiary 
beds of British Columbia have furnished a single species of Hem- 
erobidae, belonging to an extinct genus allied to Micromus and 
which I have called Bothromicromus ; it has been described 2 under 
the name of B. Lachlani. 
The number of species of tertiary Planipennia is nearly 
doubled by the discoveries already made in the American tertia- 
1 Bull. U. S. Geol. Surv. Terr., iv, 540. 2 Report Geol. Surv. Can., 1876-77, p. 462. 
