May, 1953 
by that name than it does canadense. Walsh's 
use of the name interpunctata thus may 
safely be considered to have been based on a 
misidentification. 
Stenonema canadense is an extremely vari- 
able species, being almost entirely black in 
northern Ontario and gradinz to an almost 
entirely yellow form in southern Illinois. 
Mave.—Length of body 8-10 mm., of fore 
wing 9-11 mm. Face white, with black 
streak ventral to each antennal base, in dark- 
est specimens entire frontal shelf black; 
eyes in life light green; vertex red-brown, 
often with median, black shading. Mesono- 
tum dark red-brown, often with a longitu- 
dinal, median, black stripe, scutellum some- 
times yellow-brown, usually dark; semi- 
membranous area anterior to base of fore 
wing yellow to bright red-brown; pleuron 
yellow, with variable amounts of dark brown 
and black shading, and an oblique, dark 
streak always present ventral to base of 
fore wing; sternum yellow, sometimes 
shaded with dark brown; fore leg deep yel- 
low to light brown, apex of tibia black, 
tarsus largely shaded with gray, first tarsal 
segment from two-fifths to three-fifths as 
long as second; middle and hind legs yellow 
to tan; all femora with median and apical, 
dark brown or black shaded areas; wings 
hyaline, stigmatic area of fore wing stained 
with brown, veins yellow-brown, crossveins 
dark brown or black; veins and crossveins 
in hind wing yellow to yellow-brown, outer 
margin of hind wing shaded with brown. 
Abdomen with ground color yellow; tergites 
varying widely, in some specimens almost 
completely black, in others with only a black 
crossline at posterior margin of each tergite 
and a median, longitudinal, gray line ex- 
tending partly or completely the length of 
dorsum; spiracular marks present in lighter 
specimens, these marks fusing with dark 
shading of tergites in darker specimens; api- 
cal three tergites shaded with red-brown; 
genitalia, fig. 334, yellow; caudal filaments 
gray-yellow to light yellow, articulations 
dark brown. 
NympH.—Length of body 8-11 mm. 
Head anterior to eyes uniform brown, no 
median, pale spot on meson of anterior mar- 
‘gin, but usually pale spot on this margin 
anterior to each antennal socket; large, pale 
spots lateral to compound eyes. “Thoracic 
dorsum mostly brown, a pair of large, sub- 
Burks: THE Mayrtigs oF ILLINors 165 
lateral, pale spots usually present on prono- 
tum; tarsal claws without ventral denticles. 
Dorsum of abdomen brown, with a pair of 
somewhat variable, longitudinal, submedian, 
pale stripes and a row of pale spots near 
either lateral margin; gills borne by seg- 
ments 1-6 pointed at apexes, gills of seventh 
pair each with one trachea; apical two or 
three abdominal sternites with longitudinal, 
brown band at lateral margins, more an- 
terior sternites either unmarked or with 
vague, brown spots near lateral margins, 
entire apical fourth of ninth sternite brown; 
posterolateral angles of segments 7—9 spine- 
like; caudal filaments light brown, articula- 
tions perceptibly darker near apexes of fila- 
ments. 
Known from Arkansas, Connecticut, Ili- 
nois, Indiana, Manitoba, Michigan, Minne- 
sota, New Jersey, New York, North Caro- 
lina, Ohio, Oklahoma, Ontario, Tennessee, 
Quebec, West Virginia, and Wisconsin. 
Illinois Records.—Adult specimens, col- 
lected April 10 to September 17, are from 
Alton, Apple River Canyon State Park, 
Aroma Park, Aurora, Carlinville, Cedar- 
ville, Charleston, Chicago, Crescent City, 
Erie, Fieldon, Freeport, Galena, Golconda, 
Havana, Kankakee, La Grange, Mahomet, 
Milan, Momence, Mount Vernon, Oakwood, 
Oregon, Palisades State Park, Prophets- 
town, Quincy, Richmond, Rock City, Rock- 
ford, Rock Island, Spring Grove, St. Charles, 
Starved Rock State Park, Sterling, Urbana, 
Waukegan, White Pines Forest State Park, 
and Wilmington. 
7. Stenonema frontale (Banks) 
Heptagenia frontalis Banks (1910:199). 
Stenonema interpunctatum frontale (Banks). 
Spieth (1947:109). 
Stenonema majus Traver (1935a:320). 
The type of frontale is, unfortunately, in 
quite poor condition, but the species can be 
placed with reasonable certainty despite 
this. 
Mare.—Length of body 8-10 mm., of 
fore wing 9-11 mm. Face below antennae 
yellow, black marks below each antennal 
socket; vertex yellow, shaded with brown 
near posterior margin; compound eyes in 
life light green; each antennal scape and 
pedicel yellow, flagellum gray-tan at base, 
becoming hyaline at apex. Mesonotum dark 
