May, 1953 
near Chicago on the Des Plaines River; 
Coal Valley Creek, Rock Island County; 
and Rock Island.) 
3. Siphlonurus quebecensis 
(Provancher) 
Baetis canadensis Provancher (1876: 267), 
not Walker. Misidentification. 
Siphlurus quebecensis Provancher (1878:127). 
New name. 
Siphlurus annulatus Provancher (1878: 144), 
not Walker. Erroneous citation. 
Siphlurus triangularis Clemens (1915a:250). 
Mate.—Length of body 9-12 mm., of 
fore wing 10-14 mm. Head yellow, with 
dark brown to black shading at bases of 
ocelli, on vertex at mesal margins of com- 
pound eyes, and across frontal shelf below 
antennae; compound eyes gray, the lower 
portion with two light bands alternated 
with two dark bands extending across 
outer surface; antennae light brown. 
Thorax brown, with light yellow or white 
marks on pleura and sternum; wings hya- 
line, veins and crossveins dark brown, costal 
and subcostal crossveins weak, stigmatic 
crossveins anastomosed and stigmatic areas 
milky; legs light brown, with dark brown 
marks at apexes of femora, tibiae, and tarsal 
segments. Ground color of abdomen light 
yellow-tan, dark brown shading covering all 
but anterior quarter of each tergite; triangu- 
lar, shaded area at lateral margin of each 
sternite, these triangles connected on meson 
by a V-shaped mark with its apex on median 
point of anterior margin of each sternite; 
genitalia, fig. 242, brown; cerci light tan at 
bases, becoming almost white at apexes, 
articulations dark brown. 
FEMALE.—Length of body 10-12 mm., of 
fore wing 12-14 mm. Coloration identical 
with that of male, except that caudal fila- 
ments are slightly lighter in color; apical 
margin of terminal abdominal sternite with 
a small, rounded, median notch. 
NympH.—Length of body 10-12 mm., of 
caudal filaments 5-6 mm. Body light tan, 
with brown shading; legs tan, each with 
brown annulation near apex of femur, at 
base of tibia, and at base and apex of tarsus, 
these annulations not always completely en- 
circling leg. Gills on abdominal segments | 
and 2 double, others single; spinelike, pos- 
terolateral angles of abdominal tergites dark 
brown at apexes; abdominal sternites with 
dark markings broad, abdominal color pat- 
Burks: THE MAyF ties oF ILLINOIS 107 
tern otherwise identical with that of adult; 
caudal filaments each with a broad, brown 
crossband near apex. 
Known from Connecticut, Illinois, Maine, 
Michigan, New York, North Carolina, On- 
tario, Quebec, South Carolina, and Wis- 
consin. 
Illinois Record.—SoutuH Be torr: Rock 
River, May 31, 1927, D. H. Thompson, 
3N. 
4. Siphlonurus typicus (Eaton) 
Siphlurus typicus Eaton (1885:222). 
Siphlonurus berenice McDunnough (1923:49). 
Siphlonurus novangliae McDunnough 
(1924¢:75). 
Spieth (1941a:93) studied Eaton’s type 
and established the above synonymy. 
Mave.—Length of body 9-10 mm., of fore 
wing 10-11 mm. Head chiefly yellowish tan, 
light yellow on face below ocelli and shaded 
with dark brown at bases of ocelli; antennae 
very light tan, almost white; eyes gray. 
Thorax light yellow-brown, with white spots 
on pleura and on sternum; membrane of 
wings faintly stained with tan, veins and 
crossveins rich red-brown, costal and sub- 
costal crossveins well developed, stigmatic 
crossveins very little anastomosed; legs yel- 
low, darkened with brown at apexes of tibiae 
and tarsal segments. Abdominal ground 
color pale yellow to white, with light red- 
brown shading: each tergite with transverse, 
broad, shaded area at posterior margin, tri- 
angular, shaded area at each posterolateral 
angle, and broad, median, longitudinal spot; 
sternum virtually or quite unmarked, at most 
with faint, transverse, sinuate brown mark- 
ings on anterior sternites; genitalia, fig. 244, 
yellow-tan; caudal filaments tan at bases, 
fading to white at apexes, articulations red- 
brown. 
Nymph unknown. 
Siphlonurus typicus is known from Con- 
necticut, Illinois, Maine, Massachusetts, 
New Hampshire, New York, Pennsylvania, 
and Quebec. 
Illinois Record.—Atto Pass: Aprii 30, 
1942, Mohr & Burks, 1 ¢. 
5. Siphlonurus marshalli Vraver 
Siphlonurus marshalli Traver (1934:236). 
Mate.—Length of body and of fore wing 
10-13 mm. Head chiefly dark brown, light 
