266 
Psyche 
[June-September 
Figure 3. Protereisma directum, n.sp. Photograph of paratype, MCZ 5182a, 
Permian of Oklahoma. Length of fore wing, 32 mm. 
todonata. Serrated anterior margins are present in the existing Odo- 
nata and occur in isolated families of some other Recent orders, but 
their functional significance is not understood. 2 
In addition to the specimens of directum, there are several other 
isolated wings belonging to Protereisma. One of these (MCZ 
5185ab) appears to be a large specimen of P. arcuatum Sellards, 
described from Elmo. Six other specimens are clearly Protereisma 
but are too incomplete for specific determination. Zimmerman 
(Tasch and Zimmerman, 1962) has figured a specimen of a mayfly 
from a deposit a few feet above the Midco insect bed in which the 
MCZ specimens were collected. I have not seen that specimen, 
which he identifies as P. latum Sellards. It might be that species, but 
if the costal brace is formed as shown in his figure, the insect could 
not even be assigned to the Protereismatidae. 
2 In some existing insects the serrate margins appear to have a function in aggressive 
behavior. See Owen’s account of the butterfly genus Charaxes (1961). 
