32 Intinotis NarurAL History Survey BULLETIN 
are in the Museum of Comparative Zo- 
ology. By common consent, the identity of 
this species has long been based on the 
characters of Walsh’s species, although Say’s 
name has priority. There is at present no 
reason for changing this practice, as is 
mentioned below under neglectus. 
Mave.—Length of body 7-9 mm., of fore 
wing 8-10 mm. Compound eyes large, fig. 
56; wings with all crossveins hyaline or, in 
occasional specimens, with a few anterior 
crossveins of each fore wing darkened; ab- 
domen with a row of salmon-pink spots 
on either side; cerci and median caudal fila- 
ment with articulations darkened. 
FeMALE.—Length of body 8-10 mm., of 
fore wing 9-11 mm. Compound eyes small, 
each less than half the size of eye of male; 
wings with crossveins darkened; abdomen 
with a row of salmon-pink spots on either 
side; cerci and median caudal filament with 
articulations darkened. 
Known from the midwestern and north- 
eastern states. Develops in large and mod- 
erate-sized rivers. 
Illinois Records.—Adult specimens, col- 
lected May 2 to August 16, are from An- 
tioch, Aurora, Bloomington, Champaign, 
Dixon (Rock River), Foster (Mississippi 
River), Hardin (Illinois River), Kankakee, 
Keithsburg, Mount Carmel, Oregon, Proph- 
etstown (Rock River), Quincy, Rockford, 
Rock Island, Rockton, Savanna (Mississippi 
River), South Beloit, Sterling, Warsaw 
(Mississippi River), Wilmington, Yorkville. 
3. Potamanthus distinctus Traver 
Potamanthus distinctus Traver (1935a: 280). 
The crossveins of the fore and hind wings 
are black in both sexes; the fore wing is 11 
mm. long; there is a reddish-tan stripe on 
the vertex, pronotum, and the anterior part 
of the mesonotum; the abdomen has a 
salmon-pink stripe on either side; and the 
articulations of the cerci and the median 
caudal filament are darkened. The com- 
pound eyes of the male are moderately large, 
fig. 58. 
Known from New York and Ohio. 
4. Potamanthus neglectus TVraver 
Potamanthus neglectus Traver (1935a:282). 
In describing this species, Traver men- 
tioned that it might eventually prove to be a 
Vol. 26, Art. 1 
synonym of verticis. There is, however, 
nothing in the original description of Say’s 
species that would conclusively decide the 
matter; if neglectus were to be placed as a 
synonym of verticis, it would then be neces- 
sary to resurrect from synonymy the name 
flaveola for that species at present being 
called verticis. I prefer to follow McDun- 
nough (1926:186) in considering flaveola a 
synonym of verticis, as there is no strong 
reason for not doing so, and the present 
known distribution of the species involved is 
in agreement with that practice. P. verticis 
was described from Indiana, and flaveola 
was described from Illinois; the species now 
going under the name verticis occurs in the 
midwestern and northeastern states. P. 
neglectus is known only from the Atlantic 
Seaboard. 
The crossveins in the wings in both sexes 
are darkened; the length of the fore wing 
of the male is 8-9 mm.; there is a reddish- 
brown median stripe on the vertex of the 
head, on the pronotum, and on the mesono- 
tum; the abdomen has a row of salmon-pink 
spots on either side; the caudal filaments 
have the articulations darkened; the com- 
pound eyes of the male are small, as in 
myops, fig. 57. 
Known from Maryland, New York, and 
Pennsylvania. 
EPHORONINAE 
The subfamily Ephoroninae includes only 
one genus in the Neartic region, Ephoron. 
As used here, this subfamily corresponds 
to the second section of the family Poly- 
mitarcidae in Ulmer’s classification (1933: 
197): 
4. EPHORON Williamson 
Ephoron Williamson (1802:71). 
Polymitarcys Eaton (1868: 84). 
The adults of Ephoron are fairly large, 
snow-white mayflies with all legs of the 
females and the middle and hind legs of 
the males greatly reduced and functionless. 
The females do not molt to the adult stage, 
but mate and lay their eggs as subimagoes. 
The costal and subcostal areas of the fore 
wing are grayish purple; otherwise the wings 
are snow-white. ‘These wings, fig. 38, have 
extremely abundant crossveins and netlike 
marginal intercalaries suggesting the archaic 
