54 ILLinois NaruraAt History Survey BULLETIN 
a black median spot; spiracular marks 
present on segments 2-9, those on segment 7 
largest; a black mark present near middle 
of each lateral margin of sternites 2-9; 
genital forceps, fig. 104, slender, almost 
straight; caudal filaments white. 
FeMALe.—Length of body 2.5-3.0 mm., 
of fore wing 3.0-3.5 mm. Color as in male, 
except that fore femur is gray, shaded only 
on ventral side near base and dorsally near 
apex; fore tibia white. 
Holotype, male.—Giant City State Park, 
Illinois, at light, August 6, 1946, Mohr & 
Sanderson. Specimen in alcohol. 
Allotype, female—Same data as for 
holotype. Specimen in alcohol. 
Paratypes.—ILLINoIS: Same data as for 
holotype, 72, 339; same locality: July 5, 
1944, Sanderson & Leighton, 469 ; Aug. 22, 
1944,24, 159. Hamitton: Aug. 30, 1931, 
Ross & Mohr, 624. Herop: July 8-11, 
DeLong & Ross, 254, 3692. All specimens 
in alcohol. 
9. Caenis jocosa McDunnough 
Caenis jocosa McDunnough (1931le: 260). 
Matve.—Length of body and of fore wing 
3 mm. Head below antennae, and on pos- 
terior third of vertex, light yellow; anterior 
two-thirds of vertex shaded with purplish 
gray; antennae pale yellow, almost white. 
Pronotum light yellow, with black shading 
at lateral margins and on dorsal meson; 
area around fore coxal cavities, and on outer 
side of each coxa, shaded with black, fore 
femur shaded with gray, this shading darker 
near base and on dorsal side near apex of 
femur, fore tibia light gray; mesonotum 
yellow-brown, shaded with dark brown on 
dorsal, longitudinal, median line and at 
apex of mesoscutum; mesoscutellum shaded 
with gray at apex; metanotum yellow- 
brown, with dark brown shading on meson; 
pleuron yellow-brown, shaded with black 
around coxal cavities; thoracic sternum 
light yellow, almost white; middle and hind 
legs light yellow, with a black streak on the 
outer side of each trochanter and a black 
apicodorsal spot on each femur. Abdomen 
very light yellow, tergites 1-7 shaded with 
gray; spiracular marks present on segments 
1-7 or -8, sometimes these marks wanting 
on segments 3 or 4; abdominal sternites pale 
yellow, with a pair of lateral, black streaks 
on each sternite 1-5 and a pair of black 
Vol. 26, Art. 1 
dots on each of the more posterior sternites; 
genital forceps, fig. 102, relatively long and 
slender. 
FEMALE.—Length of body and of fore 
wing each 4 mm. Coloration identical with 
that of male except that fore femur is white, 
with gray shading in middle and near apex, 
and that thorax has more extensive, black 
or gray shading and little or no dark brown 
shading. 
Known from the northeastern and mid- 
western states and southeastern Canadian 
provinces. Possibly a pond species. 
Illinois Records.—ANNA: May 6, 1925, 
T. H. Frison, 2¢, 222. Homer: at light, 
Aug. 10, 1925, T. H. Frison, 14,39. 
10. Caenis forcipata McDunnough 
Caenis forcipata McDunnough (1931e:257). 
This species, described from Ontario and 
Quebec, may eventually be shown to be a 
synonym of latipennis Banks, described from 
the state of Washington. The male genitalia 
of the two species are virtually identical, 
figs. 103, 108. 
Mave.—Length of body and of fore wing 
4 mm. Head below vertex light yellow, 
almost white; anterior two-thirds of vertex 
dark gray, posterior third light yellow; an- 
tennae white, apex of each pedicel slightly 
darkened. Pronotum light yellow, shaded 
with purplish gray at margins; prosternum 
white, with black lateral margins; each fore 
femur shaded with dark gray, with a black 
apicodorsal spot, fore tibia gray; meso- and 
metanotum and pleuron dark yellow-brown; 
sternum white; middle and hind femora 
white, with a subapical, dorsal, black spot 
on each. Abdomen pale yellow; tergites 1—7 
heavily shaded with dark gray, stigmatic 
marks present on segments 1-7 or —8; ster- 
nites pale yellow, with paired, gray dots 
faint; genital forceps, fig. 103, long and 
slender. 
FEMALE.—Length of body and of fore 
wing 4.0-4.5 mm. Coloration identical with 
that of male except that the yellow-brown 
of the mesonotum is lighter and the gray 
shading of the fore femur is less extensive. 
Known from Illinois, Manitoba, Michi- 
gan, New York, Ontario, Quebec, and Wis- 
consin. Possibly a pond species. 
Illinois Records—AntiocH: Channel 
Lake, June 15, 1928, T. H. Frisonjeite 
SHAWNEETOWN: May 11, 1935, C. O. Mohr, 
