1947] 
Early Insect Life 
81 
appear in the Permian. The best known of these is the 
Ephemerida or may-flies, remains of which have been 
found in the Lower Permian rocks of Kansas and Okla- 
homa, as well as in Upper Permian deposits of Russia. 
They were about the same size as living may-flies, with a 
wing expanse of less than two inches. Their antennae 
were much longer than those of existing species, however, 
and the prothorax was slightly broadened, with an indica- 
tion of membranous lobes in some species. The abdomen, 
which terminated in long cerci and a median caudal fila- 
ment, closely resembled that of Recent members of the 
order. The wings were their most interesting structures. 
Living members of the order, and even those from Meso- 
zoic rocks, have greatly reduced hind wings ; but in the 
Permian species, the hind wings were about equal to the 
fore wings in size, and had nearly the same venation. 
Some of the specimens from the Lower Permian of Kan- 
sas are clearly in the subimaginal stage, showing that this 
distinctive phase of ephemerid metamorphosis occurred 
even in those early days. Several nymphs, found in the 
Permian of Oklahoma and Russia, have the character- 
istics of living epliemerids — swimming legs, caudal fila- 
ments, and lateral abdominal gills. 
True Odonata are represented in Permian strata only 
by wings. They have been found in Permian rocks in 
North America, Russia and Australia. Most species were 
surprisingly small, a few being less than an inch and a 
half across the wings. Both dragon-fly and damsel-fly 
types were present in the Lower Permian. Their nymphs 
are unknown, but they were almost certainly aquatic. 
The Corrodentia or bark lice are relatively common in 
Permian strata. Like existing species, they were very 
small and even minute, most having a wing expanse of 
about half an inch, some a quarter of an inch. The body 
structure of a few Lower Permian species is well known. 
The head was relatively large, with long antennae and 
prominent eyes (Figure 7). Surprising enough, the ante- 
rior part of the head was prolonged into a short rostrum, 
but whether the mouth-parts were adapted for chewing 
or some other method of feeding has not been determined. 
