190 Ittinoris NatuRAL History SurvEY BULLETIN 
Fig. 385. — Heptagenia perfida, mature 
nymph, dorsal aspect. 
orange shading. Thorax dull brown dor- 
sally, light yellow ventrally. Abdomen dull 
brown dorsally, darker at posterior margins 
of tergites, sternites light yellow; posterior 
margin of terminal sternite produced and 
truncate on meson; caudal filaments light 
yellow, basal articulations tan. 
NympH.—Fig. 385. Length of body 6-8 
mm. Head slightly wider than thorax, dor- 
sal side of head brown, with a pair of sub- 
mesal, white spots on anterior margin, a 
second small pair of white spots just pos- 
terior to these, three fairly large spots be- 
tween eyes and posterior to antennal bases, 
and a white streak extending from antero- 
lateral angle of each compound eye to mar- 
Vol. 26, Art. 1 
gin of head. Thorax brown, marked with 
obscure, paler spots; each tarsal claw with 
basal tooth virtually wanting and only three 
to five ventral denticles. Dorsum of abdo- 
men brown, tergites 1-7 each with a pair 
of submedian, white streaks, usually a pair 
of small, white dots at posterior margin 
lateral to submedian streaks, and a pair of 
posterolateral, white, triangular marks; 
median area of tergites 8 and 9 each with 
a large, white blotch; filamentous tuft ab- 
sent in gills borne by seventh segment, tuft 
borne by sixth pair of gills reduced in size; 
abdominal sternites each with a slightly 
irregular, brown crossband at anterior mar- 
gin; caudal filaments tan, unmarked. 
Known from Illinois and Ontario. 
Illinois Records.—Atto Pass: May 31, 
1940, B. D. Burks, 246; Union Springs 
Church, May 12, 1939, Burks & Riegel, 
28; June 1, 1940, B. D. Burks, 13, 1 N; 
May 3, 1946, Burks & Sanderson, 23, 12; 
May 15, 1946, Mohr & Burks, 24, 29; 
branch of Clear Creek, May 19, 1946, Mohr 
& Burks, 2¢, 12. Cora: May 3, 1946, 
Burks & Sanderson, 18, 12. EppyviLieE: 
Lusk Creek, June 6, 1946, Mohr & Burks, 
14. Gotconna: May 13, 1939, Burks & 
Riegel, 23, 2 N. JoNeEsBoro: branch of 
Clear Creek, May 15, 1946, Mohr & Burks, 
7. Oakwoopn: Salt Fork River, May 22, 
1942, Ross & Burks, 1¢. Wotr LAKE: 
Hutchins Creek, May 15-June 1, 1940, B. 
D. Burks, 44,2 N. 
MACULIPENNIS Group 
12. Heptagenia umbratica McDunnough 
Heptagenia umbratica McDunnough 
(1931b:92). 
Mate.—Length of body 7-8 mm., of fore 
wing 8-9 mm. Frontal shelf of head stained 
with brown, and with a transverse, black 
streak across base, face above frontal shelf 
yellow, vertex brown; compound eyes sep- 
arated on meson by a space as wide as a 
lateral ocellus. Thoracic notum and pleura 
dull brown, sternum yellow. Legs light yel- 
low, fore femur, tibia, and tarsus shaded — 
with brown; first fore tarsal segment one- — 
fourth to one-fifth as long as second seg- — 
ment; wings hyaline, veins and crossveins — 
in costal half of fore wing brown, others — 
colorless. Abdomen yellow, tergites with 
posterior margin black and dorsal area 
