324 
areas milky; veins pale and almost con- 
colorous with connecting membrane. 
Abdomen, fig. 100, with no distinctive 
features except for shape of subgenital 
plate on posterior margin of eighth ster- 
nite; subgenital plate extends somewhat 
over ninth sternite, is broadly rounded on 
posterior margin, slightly indented at tip, 
and with a concave, transverse valley at 
NyYMPHAL 
MANDIBLES 
a sat 
\: ge Ya 
_ ‘one 
NYMPHAL NYMPHAL LABIUM 
MAXILLA 
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i} 
Fe 
ADULT HEAD 
AND PRONOTUM 
ihe. | i: 
pele Ar 
gu ined eY) 
’ Lp py Cede 
aly hh 
No 
"Ay Ais fj 
We 
\vik Whi 
RA ie (phil yt 
SOU MO Uy AL 
9 SUBGENITAL PLATE 
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Fig. 100.—Isoperla orata. 
Intinois NAaturAL Hisrory SURVEY BULLETIN 
ABDOMINAL STERNITES 
G ABDOMINAL SEGMENTS 
Vol. 22, Arta 
its base; subgenital plate, as viewed from 
side, tends to extend away from abdomen 
much as in fruncata Frison. 
Length to tip of wings 11 mm.; length 
to tip of abdomen 7 mm. 
Mare.—Head, thorax and basal ab- 
dominal segments in general similar to 
those of female, but slightly smaller in 
size. Important differences or structures 
are as follows: tenth tergite not cleft, fig. 
100, subanal lobes weakly developed and 
but slightly visible from above; ninth 
sternite, fig. 100, produced backwards so 
that apical tergites are not visible ‘in 
ventral view; eighth sternite with a shal- 
lowly recessed but distinct lobe in middle 
of posterior margin. 
Holotype, female. — Gatlinburg, Le Conte 
Creek, Tenn.: reared from nymph, May 14, 
1939, T. H. Frison & H. H. Ross. 
Allotype, male——Same data as for holo- 
type. 
Paratypes.— TEN NESSEE.—GATLINBURG: Same 
data as for holotype, 52; same data as for 
holotype except not reared, 56, 182; June 
14, 1940, T. H. Frison et al., 19, reared from 
nymph; same data except not reared, 1694 
fork of Little Pigeon River, May 27, 1934, T. 
H. Frison, 1¢, 49; Fighting Creek Gap, 
May 15, 1939, T. H. Frison & H. H. Ross, 1 da 
29. ELKMOoNT, June 13, 1940, T. H. Frisom 
Cingl elas 
New York.—Keene, tributary of Sable Riv- 
er: June 20, 1941, T. HH. Frison G.5e H. 
Ross, 34, 49. EusBa MILLS, Adirondack Park: 
June 20, 1941, T. H. Frison & H. H. Ross, 
13, 19. HAWKINSVILLE, Black River: June 
19, 1941, T. H. Frison & H. H. Ross. 
New Hampsuire. — Benton, Witcherville 
Brook: June 21, 1941, T. H. Frison & H. H. 
Ross; 1266) ae 
NortH CAROLINA.—SMOKEMONT, Oconaluftee 
River: May 28, 1934, T. H. Frison. 
PENNSYLVANIA.—SWIETWATER, Monroe Coun- 
ty: 1928, F. R. Nevin,-29 CAIN Sse 
VERMONT. — TopsHaAM, Waits River: June 
21, 1941, T. H. Frison & H. H. Ross, erage 
Nymeu.—General color yellow with 
dark markings on dorsum of head, thorax 
and abdomen, fig. 101. Legs, antennae 
and anal cerci dominantly pale yellow. 
Short, stout, spinelike setae, in addition 
to longer hairs, present on body and legs 
but bases not conspicuous as in such spe- 
cies as decepta Frison and dicala Frison, 
the latter described in this paper. Ocelli 
in same relative position as in adult. Basal 
segments of mouthparts not extending out 
from sides of head. Labium, maxillae and 
mandibles as in fig. 100. 
Pronotum broader than long with dark 
markings on disk, as in fig. 101. 
Longitudinal dark stripes on abdominal 
