May, 1953 
Illinois Records.—Mazon : Mazon 
Creek, May 16, 1938, Ross & Burks, 2 N. 
Oakwoop: May 24, 1926, T. H. Frison, 
26, 392. SERENA, Indian Creek: May 12, 
1938, Ross & Burks, 17 N; May 16, 1938, 
He), Burks, 2°N: 
4. Pseudocloeon myrsum new species 
This species resembles rubrolaterale Mc- 
Dunnough (19315:86) in possessing large, 
lateral, red-brown spots on the abdominal 
tergites and median, brown dots on the 
sternites, but differs in that each tergite 
possesses a pair of submedian, red-brown 
dots with a median, longitudinal, red mark 
between each pair of dots. This species like- 
wise resembles anoka Daggy (1945:391) in 
possessing a large, brown mark on abdom- 
inal tergites 2 and 6, but differs in possess- 
ing the submedian dots and median marks 
mentioned above, as well as the lateral, 
red-brown spots. 
Mare.—Length of body 3.5-4.0 mm., of 
fore wing 5.0-5.5 mm. Head dark yellow- 
brown, bright yellow around bases of an- 
tennae and at lateral angles of frontal shelf; 
ocelli yellow; faceted portion of upper sec- 
tion of each compound eye (in life) tan, 
columnar portion yellow, lower section of 
eye brown; scape and pedicel of antenna 
brown, flagellum yellow. Thorax dark, rich 
brown dorsally, with bright yellow mark- 
ings along sutures; pleura and sternum 
mostly yellow, with dark brown shading 
only in central areas of scleromes; wings 
hyaline, each stained with red at base of 
costa and on anterior wing sclerites, base of 
subcosta dark brown, this color extending 
across wing base to vein 1A; veins and cross- 
veins hyaline, stigmatic crossveins slanting, 
partially anastomosed; legs very light yel- 
low, almost hyaline, with coxae brown and 
each femur stained with red-brown at base, 
middle, and apex; fore femur shaded with 
dull brown in basal three-fourths; each 
tibia shaded with rose red in middle, fore 
tibia shaded with dull brown at apex. First 
abdominal segment dull brown: tergites 2-6 
hyaline, faintly stained with tan; tergites 2 
and 6 each with a large, median, brown spot, 
each of tergites 2-6 with a pair of sub- 
median, dark red or red-brown dots and a 
vague, longitudinal, median, red mark be- 
tween each pair of dots; a large, vague, red- 
brown spot near lateral margin of each of 
Burks: THE MAyYFtLies oF ILLINOIS 139 
these tergites and a pair of longitudinal, 
black spiracular lines on each tergite; apical 
four tergites yellow-brown, tergite 7 shaded 
on all but lateral and apical margins with 
dark red-brown; abdominal sternum hya- 
line, with a median, dark red-brown dot at 
posterior margin of sternites 2—, 3-, or 4-8; 
sternites 7 and 8 faintly shaded with red or 
red-brown; genitalia and caudal filaments 
white. 
FEMALE.—Length of body 5 mm., of fore 
wing 6 mm. Body bright golden-brown; yel- 
low at apex of mesoscutellum, on apical 
abdominal tergite, and on venter of entire 
body; lateral, brown shading of tergites 2-6 
faintly indicated; legs as in male, except 
that each fore femur is almost completely 
brown; costal vein of fore wing red at base, 
but basal, brown area of male wanting; 
caudal filaments white, each faintly stained 
with yellow at base. 
NympH.—Length of body 5.0-5.5 mm., 
caudal filaments 3.0-3.5 mm. Head yellow, 
faintly shaded with brown on face. Thorax 
white or tan, mottled with brown on dorsum 
and pleura, venter white; wingpads with 
pattern of future adult, longitudinal veins 
shown by brown lines; legs white, each 
femur with a brown cloud at base and middle 
and, sometimes, at apex. Abdomen white 
or tan, with brown shading: tergites 1 and 
2 almost completely shaded with brown, a 
pair of submedian, circular, light spots at 
posterior margin of each, tergite 2 with a 
large, median, brown spot; tergites 2-5 
mostly light, with a pair of submedian, 
brown dots on each; tergites 6 and 7 shaded 
like tergite 1; tergites 8 and 9 light, each 
with two pairs of submedian, brown dots; 
tergite 10 light, with a pair of submedian, 
brown streaks and a pair of dark spots at 
lateral margins; in dark individuals, these 
dark areas and spots tend to spread and 
almost coalesce; gills hyaline, tracheae pin- 
nate, brown; abdominal sternum white or 
tan, with a pair of submedian, brown dots 
on each of sternites 2—7; apical sternites 
usually uniformly shaded with brown; cerci 
white, except for a brown apex and a brown 
crossband at middle of each. 
Holotype, male. — Eddyville, Illinois, 
Lusk Creek, May 16-17, 1947, B. D. Burks. 
Specimen dry, on pin. 
Allotype, female.—Wolf Lake, Illinois, 
Hutchins Creek, April 2-3, 1946, Burks & 
Sanderson. Specimen dry, on pin. 
