112 Ittinois NarurAL History SurRvEY BULLETIN 
4. Isonychia sicca (Walsh) 
Baetis sicca Walsh (1862:371). 
The lectotype male of this species is in 
the Museum of Comparative Zoology. 
Ma.e.—Length of body 9-11 mm., of 
fore wing 10-12 mm. Head dark red-brown, 
antennae brown, fading to light yellow at 
tips of flagella. Thorax dark red-brown; 
wings hyaline, veins and crossveins brown; 
each fore leg with femur and tibia red- 
brown, tarsus yellow, with apex of each 
Vol. 26, Art. 1 
29, 1892, Forbes & Shiga, 12. Wutminc- 
TON: at light, Aug. 6, 1947, Burks & San- 
derson, 1é. 
5. Isonychia rufa McDunnough 
Isonychia rufa McDunnough (1931¢:162). 
Mave.—Length of body and of fore wing 
10-12 mm. Head light brown, antennae 
brown, shading to white at apexes of fla- 
gella. Thorax bright red-brown, sternum 
dull red-brown or beige; wings hyaline, 
Fig. 254.—Isonychia sicca, mature nymph, lateral aspect. 
tarsal segment darkened. Abdomen dark 
red-brown or very dark purplish red, venter 
slightly lighter than dorsum; genitalia, fig. 
252, light brown or yellow-brown; caudal 
filaments light yellow to white, with articu- 
lations near bases darkened. 
FeMALE.—Length of body 10-12 mm., of 
fore wing 12-14 mm. Head tan, shaded with 
red-brown. Thorax yellow-brown, with 
sternum darker brown; wings as in male. 
Abdomen dull, dark red-brown or purplish 
red, becoming lighter, yellow brown on 
apical three segments; caudal filaments light 
yellow, articulations not darkened. 
Known from Illinois, Iowa, Nebraska, 
and Ontario. 
Illinois Records—East DusBuQuE: at 
light, July 21, 1927, 59. Fosrer: Missis- 
sippi River, July 4, 1939, B. G. Berger, 12. 
Futon: July 20, 1927, Frison & Glasgow, 
14, 1192. Harrispurc: at light, Aug. 16, 
1937, Ross & Ritcher, 1¢, 12. Havana: 
12; June 23, 1894, F. Smith, 12 ; June 24, 
1894, 12; June 25, 1894, 19. Homer: 
June 30, 1925, T. H. Frison, 12. Mount 
CarMEL: June 30, 1906, 32. OrEcon: July 
9,'.1925,..'T.. He~ Frison; 1S. - Quiney: 
Mississippi River, July 6, 1939, Mohr & 
Riegel, 1 ¢ ; Aug. 13, 1889, C. A. Hart, 19. 
Rock Istanp: 36,22 (Walsh 1862:371). 
SAVANNA: July 19, 1892, Forbes, Shiga, 
Hart, & McElfresh, 3, 82 ; July 22, 1892, 
Hart & Forbes, 42; July 27, 1892, Mc- 
Elfresh, Shiga, Forbes, & Hart, 19; July 
veins faintly yellow, crossveins hyaline, stig- 
matic crossveins anastomosed; fore femur 
and tibia red-brown, and tarsus yellow, 
with brown shading at apexes of segments. 
Abdomen bright red-brown on dorsum, ven- 
ter lighter, chestnut brown; transverse, 
black line at posterior margin of each ab- 
dominal tergite, this black line often inter- 
rupted on meson; genitalia, fig. 251, yellow- 
brown; caudal filaments light yellow or tan, 
articulations at base darker. 
FEMALE.—Length of body 10-12 mm., of 
fore wing 12-14 mm. Head and thorax 
yellow-brown, the latter often also with 
reddish tinge; veins and crossveins of wings 
tan or light yellow, stigmatic crossveins 
anastomosed. Abdomen red-brown on dor- 
sum, pinkish yellow on venter; apical ab- 
dominal segment yellow; caudal filaments — 
yellow to white. 
Known from Illinois, Iowa, Kansas, Ne- — 
braska, and Ohio. 
Illinois Records.—App.Le River CANYON ~ 
STaTE Park: July 3, 1946, Burks & San- 
derson, 14. Aurora: July 9, 1925, T. H. ~ 
Frison, 2? ; July 17, 1927, Frison & Glas- — 
gow, 72. Dixon: May 31, 1914,14. FrReEE- 
port: at light, Aug. 4, 1948, 39. KANKA-_ 
KEE: July 9, 1948, Ross & Burks, 1 2 ; Aug. 
2, 1938, Burks & Boesel, 16. MonmoutTH: 
at light, June 23, 1948, L. J. Stannard, 14. 
Oakwoop: July 14, 1939, Burks & Riegel, 
14. ONarca: at light, July 9, 1948, Ross 
& Burks, 12. Orecon: July 4, 1946, Burks 
