oa 
on the Ephemeride. 39 
1868. §S. H. Scudder, in Geol. Mag. v. 175-7, and 218-19, catalogued 
three genera in addition to those of Prof. Dawson’s paper.  [‘‘ Gerephe- 
mera simplea is represented by a slight fragment of the tip of a wing; the 
wing must have been large and broad; the veins distant, weak and simple. 
It is apparently a member of the family Ephemerina.” Platephemera an- 
tiqua is referred to the same family, although the base of the wing is 
wanting, as well as apiece of the tip. A fragment of what is ‘‘ probably ” 
a portion from the middle of a wing is named Dyscritius vetustus, not- 
withstanding that ‘it is impossible to determine” from it “either the 
approximate size of the insect, or the family to which it belongs.” Li- 
thentomum Hartii is also described. Mr. Scudder correctly observes at p. 
218, that Palephemera medicva, Hitchcock (previously named Mormolu- 
coides antiquorum, Hitchcock) is not a nymph of an Ephemerid]}. 
1868. §.H. Scudder described, in the Paleontology of Illinois, p. 571-2, 
figs. 8-10, a genus Ewphemerites with two species, HE. gigas and afjinis, 
which he ranks among the Ephemeride. 
Paleeontologists have adopted a ridiculous course with 
regard to some insect fossils. -Whenever an obscure 
fragment of a well-reticulate insect’s wing is found in a 
rock, a genus is straightway set up, and the fossil named 
as a new species. The species is then referred to the 
Lphemeride, and is immediately pronounced to be a syn- 
thetic type of insects at present distantly related to one 
another in organization. This enunciation of synthetic 
types is often nothing less than a resort to random con- 
jecture respecting the affinities of animals which the 
writer is at a loss to classify. An insect allied to the 
Hphemeride which chirped like a Locust (such as Xeno- 
newra is imagined to have been), is a tolerable sample of 
these synthetic types. 
When a fossil comprises only a fragment, or even a 
complete wing of an Ephemerid, it is hardly possible to 
determine the genus, and impossible to assert the species. 
The utmost that can be learned from such a specimen is 
the approximate relations of the insect. Neuration by 
itself is not sufficient to define the species or even the 
genera of recent Hphemeride. 
The following list contains the names of the fossils 
hitherto reputed Hphemeride upon questionable grounds. 
I shall take no further notice of them. 
Genus DicryonreuRA, Goldenb. 1856. 
anthracophila, Goldenb. 1856. 
cellulosa, Hag. 1861. 
Humboldtiana, Goldenb. 1856. 
libelluloides, Goldenb. 1856. 
procera, Hag. 1861. 
