May, 1953 
31. Ephemerella funeralis McDunnough 
Ephemerella funeralis McDunnough 
(19254: 210; 1931a:39). 
Mare.—Length of body and of fore wing 
6-8 mm. Thorax and abdominal tergites 
generally red-brown, with sternites lighter 
red-brown. Wings hyaline, with all veins 
faintly yellow, and those veins near costal 
margin of deeper hue. Genitalia, fig. 148: 
lateral margins of penis lobes nearly straight 
and parallel near tips, inner peritreme angles 
acute; second forceps segment almost 
straight. 
NympPH.—Small occipital tubercles pres- 
ent. Each tarsal claw with 7 to 10 denticles. 
Abdomen with two rows of dorsal, sub- 
median tubercles diverging posteriorly; cau- 
dal filaments with long, dense setae in apical 
areas. 
Known from Georgia, Indiana, New 
York, Ohio, Ontario, Quebec, South Caro- 
lina, Virginia, and West Virginia. 
32. Ephemerella aestiva McDunnough 
Ephemerella aestiva McDunnough (1931a: 64). 
Mave.—Length of body and of fore wing 
6-7 mm. Thorax and abdominal tergites 
generally very dark brown; basal and apical 
abdominal sternites shaded with light brown, 
with median ones white. Genitalia, fig. 149: 
penis lobes each with lateral margin near 
apex nearly straight and parallel, inner peri- 
treme angle blunt; second forceps segment 
relatively straight. 
NympuH.—Head with occipital tubercles. 
Abdomen with two almost parallel rows of 
dorsal, submedian spines; caudal filaments 
bearing long setae in apical regions. 
Known from Quebec. 
33. Ephemerella attenuata McDunnough 
Ephemerella attenuata McDunnough 
(1925c:42; 1931d:209). 
Mave.—Length of body and of fore wing 
6mm. Thorax and basal abdominal tergites 
very dark brown, apical tergites lighter 
brown; basal sternites light brown, apical 
three sternites almost white; wings and veins 
hyaline. Genitalia, fig. 125, distinct from 
those of all other North American species: 
penis lobes fused almost to tips and with a 
subapical, angulate projection on either side; 
second forceps segment slightly bowed, and 
third six times as long as broad. 
Burks: THE Mayer ies oF ILLINOIS 75 
NympH.—Occipital, thoracic, and dorsal 
abdominal tubercles present; each tarsal 
claw with 8 to 10 denticles; first pair of 
platelike gills semioperculate, as in fig. 162; 
caudal filaments bearing long setae in apical 
regions. 
Known from Maryland, Ontario, and 
Quebec. 
BAETISCIDAE 
This family includes only the genus 
Baetisca, which was placed in the subfamily 
Baetiscinae of the family Baetidae by Traver 
(1935a:555) and in the family Baetiscidae 
of the superfamily Heptagenioidea by Ulmer 
(1933: 209). Whereas I agree with Ulmer 
that Baetisca represents a group sufficiently 
distinct to be properly considered a family 
rather than a subfamily, I do not agree that 
it has heptageniid affinities. The wing vena- 
tion and the number of clearly differentiated 
segments in the hind tarsus in the adults 
plainly show that this group has no near 
affinities with the heptageniid type. It is 
one of the mayflies, such as Prosopistoma, 
which has no known, closely related forms 
in the Recent fauna. 
14. BAETISCA Walsh 
Baetisca Walsh (1862:378). 
The compound eyes in the adult males of 
Baetisca are large, almost contiguous on the 
meson. The eyes project posteriorly so as 
almost completely to cover the pronotum. 
Each of these eyes is composed of a ventral 
portion made up of small facets and a much 
larger dorsal portion of large facets. The 
division between these two portions is not 
clearly marked, although in life the lower 
portion is slightly darker than the upper. 
‘The compound eyes in the females are widely 
separated, and each eye, in life, has a verti- 
cal, anterior, colored stripe near the mesal 
margin. In the males, the fore leg is about 
as long as the body; the five-segmented 
fore tarsus is more than twice as long as the 
fore tibia, and the fore tibia and fore femur 
are nearly equal in length. In adults of both 
sexes, a pair of slender and acutely pointed 
prosternal projections arise between the 
fore coxae. Each of the middle and hind 
tarsi in the males and each tarsus in the 
females has four clearly differentiated seg- 
ments. The thorax is quite thickset. 
