May, 1953 
& Sanderson, 16. PropHETSTOWN: July 
24-25, 1947, Burks & Sanderson, 3¢. 
Quincy: June 24, 1948, L. J. Stannard, 
26. SHAWNEETOWN: July 14, 1948, Mills 
& Ross, 3g. All specimens dry, on pins. 
TERMINATUM Group 
20. Stenonema luteum (Clemens) 
Heptagenia lutea Clemens (1913:252). 
Mate.—Length of body 9-11 mm., of 
fore wing 10-12 mm. Face below level of 
antennae light yellow, vertex yellow, with 
orange-red shading; eyes in life light green; 
a red-brown ring surrounding each antennal 
socket, antenna pale yellow, flagellum dark- 
ened in basal half. Thoracic notum light 
yellow, usually gray-brown shading present 
on meson of pronotum, mesoscutellum white ; 
pleuron pale yellow, dark shading present 
around all coxae, area anterior to base of 
fore wing usually faintly tinged with orange- 
brown; sternum pale yellow, anterior part 
of mesobasisternum usually shaded with 
gray-tan; fore leg dark yellow, middle and 
hind legs light yellow, each femur with a 
median and an apical, dark red-brown cross- 
band, apex of each tibia and apexes of all 
tarsal segments dark brown or black, first 
fore tarsal segment slightly less than one- 
half as long as second segment; wings hya- 
line, stigmatic area of fore wing stained with 
red-tan; veins and crossveins of fore wing 
dark brown or black, those of hind wing 
hyaline. Abdomen light yellow, posterior 
margin of each tergite 1-7 with a narrow, 
black cross-stripe; spiracular markings ab- 
sent; apical three tergites pinkish tan; geni- 
talia, fig. 349, pale yellow; caudal filaments 
pale yellow, articulations faintly darkened 
with gray, sometimes three or four basal 
articulations of each filament light brown. 
NympH.—Length of body 10 mm. Head 
with area anterior to eyes brown, freckled 
with pale dots, large, pale spots lateral to 
each compound eye and at posterior margin 
of vertex. Each lateral margin of pronotum 
with a large, light spot, disc of pronotum 
brown, with numerous minute, pale dots; 
each tarsal claw with two ventral denticles 
near apex. Abdominal tergites 3, 6, and 7 
almost entirely dark brown, others with a 
contrasting pattern of dark and light mark- 
ings, tergite 9 almost entirely light; gills 
Burks: THE Mayr igs oF ILLINOIS 75 
borne by segments 1-6 truncate at apexes, 
gills of segment 7 without tracheae; abdom- 
inal venter white, sternites 2-8 each with 
brown shading near lateral margins and at 
posterior margin, sternite 9 with two large, 
dark brown, sublateral spots; each caudal 
filament uniformly tan in basal half, apically 
with alternating pairs of segments dark and 
light. 
Known from Illinois, Ontario, and Que- 
bec. 
Illinois Records.—KANKAKEE: June 17, 
1939, B. D. Burks, 16. Momence: June 
15, 1938, Ross & Burks, 3 6 ; Aug. 5, 1938, 
Burks & Boesel, 1 ¢ ; Aug. 22, 1939, B. D. 
Burks, 16. Mount Carmet: June 25, 
1936, DeLong & Ross, 1 6. OAKwoop: June 
5, 1948, Burks & Sanderson, 14; June 9, 
1926, Frison & Auden, 12. RocKkrForp: 
May 22, 1941, Ross & Burks, 1 ¢ ; June 12, 
1938, Ross & Burks, 1¢. SAVANNA: June 
29, 1935, DeLong & Ross, 1¢. WHITE 
HeatH: Sangamon River, Aug. 5, 1939, 
Ross & Riegel, 22. 
21. Stenonema terminatum (Walsh) 
Palingenia terminata Walsh (1862:376). 
Heptagenia placita Banks (1910:199). 
New synonymy. 
The lectotype of Walsh’s species and the 
type of placita Banks are in the Museum of 
Comparative Zoology. 
Matre.—Length of body 6-8 mm., of fore 
wing 8-11 mm. Head below antennal sockets 
light yellow, vertex orange-rufous or clay 
color, with lateral, orange shading; eyes in 
life light yellow-green; each antenna white 
or faint yellow, flagellum darkened in basal 
half. Thoracic notum light clay color to 
ochraceous-tawny, apex of mesoscutellum 
white; pleuron light yellow, area anterior 
to fore wing base often tinged with light 
buff-brown, a pale orange-rufous spot dor- 
sal to each coxa; fore leg deep yellow, middle 
and hind legs light yellow, fore femur with 
a median and an apical red-brown spot, apex 
of fore tibia and apexes of all tarsal seg- 
ments dark brown or black; first fore tarsal 
segment two-fifths as long as second seg- 
ment; wings hyaline, stigmatic area faintly 
stained with yellow-brown, veins of fore 
wing light yellow-brown, crossveins brown, 
veins and crossveins of hind wing usually 
entirely hyaline. Abdomen pale yellowish, 
tergites 1-7 each with a fairly broad, but 
