NYMPHAL 
MAXILLA 
SAAY 
NYMPHAL LABIUM 
Q SUBGENITAL PLATE 
EM) Oy) Wy pee My EN 
/ 
Q SUBGENITAL. PLATE 
"I 
: ‘yf i 
is WEEN a me 
Vefy ea 
Vey sacess) 
3’ TERMINAL ABDOMINAL 
STERNITES 
36' TERMINAL ABDOMINAL 
TERGITES 
Fig. 98.—Isoperla dicala. 
Iutino1is NaturaL History SURVEY BULLETIN 
Vol. 22, Area 
deeply recessed lobe in middle of posterior 
margin. 
Length to tip of wings 11 mm.; length 
to tip of abdomen 8 mm. 
FEMALE.—Head, thorax and basal ab- 
dominal segments and appendages in gen- 
eral similar to those of male, but slightly 
larger in size. Important differences are 
as follows: eighth abdominal sternite, fig. 
98, triangularly produced over ninth ster- 
nite and with sides slightly curved inwards 
on each side just before extreme tip. 
Holotype, male.—Free Soil, Great Sable 
River, Mich.: reared from nymph, May 26, 
1939, T. H. Frison & H. H. Ross. 
Allotype, female—Same data as for holo- 
type. 
Paratypes.—MICHIGAN. — FREE SOIL: Same 
data as for holotype, 146, 89. Osceola 
County, Pine River near LUTHER: June 27, 
1936, 29. Laxe County, Pine River: June 
3 1938, R. P. Bohlard, 5a5 2@e 
Other specimens which I am identifying as 
this species but which I do not want to include 
as paratypes because of lack of nymphs from 
same general area are as follows. 
TENNESSEE.—SEVIERVILLE, at light: June 11, 
1938, IT. H. Frison & T, H® Frison,sjae 1¢, 
139. Gatuinsurc: Little Pigeon River, June 
12, 1935, .H: H. Ross; eseae light, June 11, 
1938, T. H. Frison & T. H. Frison, Jr., 1c 
June 14, 1940, T. H. Frison et al, 225 
MIssOURI.— GREER SPRINGS: June 7, 1937, H. 
He Rossie2- ee 
MINNESOTA.—PINE County, Snake River: 
May 26, 1939, P. H. Harden, 1é. 
InpIANA.—Knox, Yellow River: 
1937, H. H. Ross,-16% 
Nymeu. — General color of dorsum 
brown with small pale areas, fig. 99; 
venter, except for conspicuous, short, 
brown, spinelike setae on apical abdominal 
segments, creamy yellow. Legs, antennae 
and anal cerci dominantly pale yellow, 
with short, stout, spinelike setae on femore 
very numerous and conspicuous. Ocelli ir 
same relative position as in adult. Basa! 
segments of mouthparts not extending out 
from sides of head. Numerous conspicu: 
ous, short, stout, spinelike setae on dorsum 
particularly prominent on back of head 
anterior part of mesonotum and meta 
notum and on abdominal tergites. Labi 
um, maxillae and mandibles as in fig. 98 
Pronotum broader than long, witl 
markings as in fig. 99. 
Abdominal tergites dark with a serie 
of pale spots which tend to set off a serie 
of longitudinal dark and somewhat lighte 
colored stripes, the median and two latere 
stripes darkest, fig. 99. Cerci long, wit 
many segments, progressively longer fror 
May 24, 
