September, 1942 
Length to tip of wings 17 mm.; length 
to tip of abdomen 14 mm. 
Holotype, male. — WasutTenaw County, 
Huron River, T25, RSE, Sec. 5, Mich.: May 
31, 1937, F. E. Lyman. 
Paratypes. — MICHIGAN. — WASHTENAW 
County: Same data as for holotype, 6¢. 
NympH.—General body color yellow 
with dark brown or black markings, as 
.f 
NymMPHAL MANoIBLES 
Sy 
NyMPHAL 
LABIUM 
NyMPHAL MAXILLA 
Fig. 65.— 
Hydroperla 
nalata. 
in fig. 64. Thoracic and abdominal gills 
absent. A small finger-like gill, fig. 65, at 
cach outer posterior corner of submentum. 
Mandibles, labium and maxillae as jn fig. 
5. Occipital ridge lacking. 
Approximately mature specimens with 
ody length of 18 mm. 
Nymphal records: Same locality as for holo- 
ype with date records as follows: Jan. 29, 
937, 1 nymph; Feb, 4-20, 1937, 3 nymphs; 
Frison: NorrH AMERICAN PLECOPTERA 
295 
April 4-9, 1937, 5 nymphs; May 6, 193i ad 
nymphs; April 10-28, 1938, 6 nymphs. 
This species differs from varians 
(Walsh), crosbyi (Needham & Claassen), 
parallela Frison, harti Frison and dorata 
Frison, the last described in this paper, in 
lacking lateral stylets (paragenital plates). 
It differs from subvarians (Banks) in 
shape of supra-anal process and shape of 
lobes on tenth abdominal tergite. 
Hydroperla dorata new species 
Mare.—General features about as in 
nalata Frison, described in this paper. 
Head and pronotum with color pattern 
as in fig. 66. Important distinctive char- 
acters are as shown in figs. 62 and 66: 
Abdomen with tenth tergite cleft, the lobes 
formed by this cleft with sides adjacent to 
cletqenote-patallel@and= lobes somewhat 
thumblike; supra-anal process with tip 
strongly recurved backwards and shaped 
as in fig. 66; with lateral stylets (para- 
genital plates) flanking supra-anal process, 
both enveloped by two lobes which are 
partly sclerotized. Basal segments of anal 
cerci as in fig. 62. 
Length to tip of wings 18 mm.; length 
to tip of abdomen 16 mm. 
FEMALE.—Head, thorax, basal abdom- 
inal segments and appendages in general 
similar to those of male but slightly larger 
in size. Important differences are as fol- 
lows: eighth abdominal sternite with pos- 
terior portion forming a subgenital plate 
shaped as in fig. 66. 
Holotype, male——Near Baldwin, Pere Mar- 
quette River, Mich.: May. 10, 1940, reared 
from nymph, T. H. Frison & H. H. Ross. 
Allotype, female-——Same data as for holo- 
type. 
Paratypes. — MicHIGAN. — Near BALDWIN: 
same data as for holotype, 13; same data 
as for holotype except not reared, 19. 
PENNSYLVANIA.—ANALOMINK, Brodhead 
Creek: April 15, 1939, 12: April 23, 1939, 
16,192; April 27, 1940, 14; all P. Jennings. 
New York.—MountT Marcy: June 29, 1940, 
H. Dietrich, 1¢. PHoENEcIaA: May 5, 1940, P. 
Jennings, 26. SCHOHARIE: XDETISZ Sel) 3 Seana 
NympH (description based upon exu- 
via).—General body color yellow with 
dark brown on black markings as in fig. 
67. Thoracic and abdominal gills lacking. 
A small finger-like gill at each outer pos- 
terior corner of submentum. Mandibles. 
labium and maxillae as in fig. 66. Oc- 
cipital ridge lacking. 
