September, 1942 
was relaxed, and the important genital 
characters studied in alcohol and com- 
pared with specimens in the Illinois Natu- 
ral History Survey collection. It seems 
desirable to designate this specimen as the 
lectotype, and a female labeled “Great 
Falls, Va., 15-IV” as the lectoallotype. 
A male and a female of the original cotypic 
series, obtained by exchange, are now in 
the Survey collection. 
Although Needham & Claassen (1925) 
described the adult male and female of 
subvarians (by name of postica Walker), 
they gave no illustrations of the important 
abdominal characters. Therefore, illustra- 
tions of the head and pronotum, the basal 
segments of the anal cercus, the terminal 
SUPRA-ANAL PROCESS>< 
PARAGENITAL EES 
en)” i ) 
elit 
Mi 
fh i 
“ 
heal 
Nil 
ail, 
F 
Hs 
i 
Gertie 
mn 
\ ie 
l) 
i 
th 
ji 
s 
tl 
In 
O GENITAL 
STRUCTURES 
a 
i i 
ADULT HEAD 
AND PRONOTUM 
“- Supra- 
Fe\ ANAL 
<2) PROCESS 
PARAGENITAL 
PLATE 
3 TERMINAL ABDOMINAL 
SEGMENTS 
| i \ 
mS Ones 
—~ — All 7 
O' GENITAL STRUCTURES 
O GENITAL LOBE 
BG ABDOMINAL TERGITES 
Fig. 61—Hydroperla subvarians. 
abdominal segments, one of the lobes on 
the tenth tergite, and two views of the 
supra-anal process and enveloping lobes 
are presented, figs. 61 and 62, to aid future 
Workers with the identification of this 
species. “hese drawings are based upon a 
| 
; 
Frison: NorrH AMERICAN. PLECOPTERA 
293 
male specimen from Calais, Me., and 
differ from the lectotype solely in having 
the extreme tip of 
the supra-anal process 
more recurved _back- 
wards. 
Additional records 
for this species in the 
Illinois Natural History 
Survey collection are as 
follows. 
MAINE.—CALAIS, St. 
Croix River. june 111% 
IEE dey Moan bree NYA 
Tees 
ONTARIO. —Costello 
Lake, ALGONQUIN Park, 
Ontario Fisheries Re- 
search Laboratory: July 
35,1939; W.-M.) Sprules, 
Tea 
VIRGINIA.—GREAT 
FALLs: April 10, 1938, 
Be Deburks A. 2 ex- 
uviae. 
Fig. 62.—Anal cerci of 
Hydroperla  subvarians 
and H. dorata. 
SUBVARIANS 
DORATA 
This species differs from  varians 
(Walsh), crosbyi (Needham & Claassen), 
parallela Frison, harti Frison and dorata 
Frison, the last described in this article, 
in lacking lateral stylets (paragenital 
plates). It differs from nalata Frison, also 
described in this paper, in the shape of 
supra-anal process and shape of lobes on 
tenth abdominal tergite. 
Hydroperla nalata new species 
MaAvLeE.—General body color black or 
dark brown with some yellow areas on 
head, thorax and abdomen. Dorsum of 
head and pronotum with dark and yellow 
areas, as in fig. 63. First abdominal ter- 
gite in part whitish, second through eighth 
tergites dominantly black or dark brown, 
ninth tergite with anterior portion dark 
and posterior portion yellow, tenth ter- 
gite yellow. Legs black or dark brown, 
with some yellow on middle part of 
femora. Antennae and anal cerci black or 
dark brown. 
Head wider through compound. eyes 
than width of pronotum; lateral ocelli 
about as far apart as each is distant from 
median ocellus, distance from inner margin 
