176 
rather vague, dark brown or black crossband 
at posterior margin; spiracular markings 
absent; apical three tergites ochraceous- 
tawny; genitalia, fig. 350, light yellow; cau- 
dal filaments white or pale yellowish, basal 
two or three articulations of each filament 
sometimes darkened with brown. 
Known from Illinois, Manitoba, New 
York, Ontario, and Quebec. 
Illinois Records. — Monticetto: May 
24. 1947, B. D. Burks, 1¢. Orecon: July 
9, 1925, T. H. Frison, 24. Rockrorp: May 
22, 1941, Ross & Burks, 54 ; June 29, 1938, 
B. D. Burks, 22 ; Sept. 4, 1940, Frison & 
Ross, 2¢. Rock Istanp: 14¢,792 (Walsh 
1862:376). RockTron: Aug. 4, 1948, Burks 
& Stannard, 3¢. SHAWNEETOWN: July 14, 
1948, Mills & Ross, 2¢. 
22. Stenonema lepton Burks 
Stenonema lepton Burks (1946:614). 
In the male of this species, the first fore 
tarsal segment often is as much as five- 
sixths as long as the second segment. In 
previously used keys to the genera of the 
Heptageniidae, this character would refer 
the species to the genera Cinygmula, Ci- 
nygma, Epeorus, or Iron. The male genitalia 
of lepton are, however, typical for the genus 
Stenonema. 1 have, accordingly, placed it 
here. 
Several recent collections of this species 
have been made, and the specimens have 
been preserved dry, on pins. Study of these 
specimens necessitates some change in the 
color description of the species, which was 
drawn from alcoholic material. 
Matre.—Length of body 7-9 mm., of 
fore wing 8-10 mm. Face ventral to antennae 
white; four minute, gray spots on posterior 
margin of vertex between eyes: a pair at 
margins of compound eyes and a submedian 
pair; vertex near ocelli yellow, shaded with 
orange-brown posteriorly; each antenna 
white, flagellum slightly darkened in basal 
half; eyes in life chalky white. Pronotum 
very pale yellow, mesonotum chalky white, 
scutellum white, pleuron white, a faintly 
darkened streak ventral to base of fore wing 
between middle and hind coxae, and dorsal 
to hind coxa; thoracic sternum white; fore 
leg very pale yellow, red-brown shading 
present in middle and at apex of fore femur, 
apex of fore tibia and apexes of all fore 
tarsal segments darkened with brown, first 
Ittinois NATURAL History SurRvEY BULLETIN 
Vol. 26, Art. 1 
fore tarsal segment from two-thirds to five- 
sixths as long as second segment; middle 
and hind legs white, femora not (or very 
faintly) shaded with red-brown in the mid- 
dle; wings hyaline, stigmatic area washed 
with very light red stain, anterior veins 
and all crossveins of fore wing yellow- 
brown, those of hind wing hyaline; posterior 
margin of hind wing slightly darkened with 
brown. Abdomen white, each of tergites 
1-9 with a narrow, black crossline at pos- 
terior margin, spiracular markings absent, 
apical three tergites shaded with faint tan 
on meson; genitalia, fig. 351, white; caudal 
filaments entirely white. 
Known only from Illinois. 
Illinois Records. — AroMA Park: July 
8, 1948, Ross & Burks, 1 ¢ ; Aug. 6, 1947, 
Burks & Sanderson, 1¢. KANKAKEE: at 
light, July 9, 1948, Ross & Burks, 32. 
Momence: at light, June 22, 1938, Ross & 
Burks, 62 ; June 24, 1939, Burks & Ayars, 
23 6. WILMINGTON: at light, Aug. 6, 1947, 
Burks & Sanderson, 10¢. 
PULCHELLUM Group 
23. Stenonema integrum (McDunnough) 
Heptagenia (Ecdyonurus?) 
nough (1924a:9). 
Stenonema bellum Traver (1933a: 202). 
New synonymy. 
Stenonema wabasha Daggy (1945:378). 
New synonymy. 
integer McDun- 
The concept of integrum followed here is 
derived entirely from a study of the holo- 
type of the species. 
Mave.—Length of body 5-7 mm., of fore 
wing 6-8 mm. Head chalky white, vertex 
stained with pale yellow, a pair of subme- 
dian, light brown dots between compound 
eyes; each antenna white, flagellum slightly 
darkened with gray. Pronotum pale yellow, 
sometimes with a lunate, black streak on 
either side; meso- and metanotum chalky 
white, with clay-colored shading along outer 
parapsides of mesonotum and just dorsal to 
fore wing bases; pleura and sternum chalky 
white, occasionally with pale yellow-brown 
shading on each pleuron near mesocoxa. 
Fore leg pale yellow, dark brown at apex 
of tibia and at apexes of tarsal segments, 
first tarsal segment three-fifths as long as 
second; middle and hind legs white; each 
femur of all legs with a prominent, red- 
et ait ta a Ne i Bet it 
