74 Ittinoris Natura History Survey BULLETIN Vol. 26, Art. 1 
General color tan to brown, often with  tergites a lighter red-brown, and venter 
vague, dark brown marks on abdominal yellow; wings and veins hyaline. Genitalia, 
dorsum. Caudal filaments with two or fig. 142, with penis lobes enlarged near 
three narrow, brown crossbands near base. apexes. 
Head, thorax, and abdomen without Nympu.—Head in male lacking occipital 
dorsal tubercles or spines; maxillary palps 
well developed; tarsal claws without den- 
ticles; posterolateral angles of abdominal 
segments 4-9 produced, spinelike, fig. 162; 
platelike gills borne by abdominal segment 
4 only partly covering more caudal pairs of 
gills; caudal filaments bearing short, sparse 
setae throughout. 
Known from Illinois, New Brunswick, 
New York, North Carolina, Ontario, Que- 
bec, and Tennessee. Develops in fairly rapid, 
moderate-sized rivers. 
Illinois Record.—RockTon : Rock River, 
June 25, 1947, B. D. Burks, 54, 7°. 
27. Ephemerella lita Burks 
Ephemerella lita Burks (1949: 235). 
Adult unknown. 
NymeH.—Length of body 8 mm., of cau- 
dal filaments 5.5 mm. General color light 
tan, with a few small, brown markings; 
caudal filaments each with a single, narrow, 
brown crossband near base. 
Head and body flat, conspicuously hairy, 
without dorsal spines or tubercles; head 
semiquadrate, with clypeo-genal margin be- 
neath each antennal base slightly incised; 
maxillary palps well developed; tarsal claws 
without denticles; posterolateral angles of 
abdominal segments 2-9 produced, spine- 
like; platelike gills of abdominal segment 4 
semioperculate, only partly covering more 
caudal pairs of gills, fig. 163; caudal fila- 
ments bearing relatively few short setae 
at each articulation, these setae slightly 
longer in apical area than in basal area of 
filaments. 
Known from Illinois. Taken in small or 
moderate-sized, fairly rapid rivers. 
Illinois Records.—D1xon: Rock River, 
May 21-22, 1925, D. H. Thompson, 5 N. 
Oakwoop: Salt Fork River, May 22, 1928, 
T. H. Frison, | N. Rockrorp: Rock River, 
June 2, 1927, D. H. Thompson, 1 N. 
28. Ephemerella bicolor Clemens 
Ephemerella bicolor Clemens (1913: 336). 
Ma ce.—Length of body and of fore wing 
5-6 mm. Thorax red-brown, abdominal 
tubercles, fig. 151, but in female having very 
small ones, fig. 152. Each tarsal claw with 
8 to 12 denticles. Abdomen with two rows 
of dorsal, submedian tubercles diverging to- 
ward rear, with pair on tergite 5 conspicu- 
ously more widely spaced than on anterior 
tergites; caudal filaments each with long 
setae in apical area. 
Known from Indiana, New Brunswick, 
New York, Nova Scotia, Ontario, and 
Quebec. 
29. Ephemerella verisimilis McDunnough 
Ephemerella virisimilis McDunnough 
(1930: 57; 1931a:65). 
Mave.—Length of body and of fore wing 
7-8 mm. Thorax and abdominal tergum 
dark brown; abdominal venter dark yellow- 
brown. Wings and veins hyaline. Genitalia, 
fig. 147, with penis lobes slightly enlarged 
near apexes. 
NympH.—Head with well-developed oc- 
cipital tubercles. Tarsal claws each bearing 
9 to 12 denticles. Abdomen with two rows 
of dorsal, submedian tubercles which di- 
verge gradually toward rear; caudal fila- 
ments with long, dense setae in apical areas. 
Known from Maine, New Brunswick, 
Ontario, and Quebec. 
30. Ephemerella minimella McDunnough 
Ephemerella minimella McDunnough 
(1931a: 63). 
Matve.—Length of body and of fore wing 
6 mm. Thorax and basal abdominal tergites 
mostly very dark brown, with apical two 
abdominal tergites lighter brown; sternum 
tan, gradually fading to white on apical two 
abdominal sternites. Genitalia, fig. 150: 
penis lobes with a rounded, preapical en- 
largement on either side, inner peritreme 
angles acute, and second forceps segment 
relatively straight. 
NymeH.—Occipital tubercles wanting in 
male and vestigial in female; dorsal, sub- 
median abdominal spines forming two rows 
evenly diverging posteriorly; caudal fila- 
ments each with long setae in apical region. 
Known from Quebec. 
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