| September, 1942 
CHEBOYGAN COUNTY, west branch Sturgeon 
River: July 3, 1938, J. W. Leonatd, 26.2 ¢. 
MONTMORENCY County, Hunt Creek: Aug. 30- 
Sept. 3, 1940, J. W. Leonard, 34, 19. 
MissouRI.— GREER SPRING: June 7, 193750 1: 
H. Ross, 26, 29. 
New Brunswick. — PETIcopiac: 
Aurich 
1939, T. H. Frison & T. H. Frison, 
Jr A Oee 
ANAGANCE: Aug. 21, 1939, T. H. Frison & 
(ae Ve. 
See, Prison, Jr, 23, 59. 
New York.—Caro.ine, Wild Flower Re- 
Aug. 16, 1928, T. H. Frison, 12. 
STRATFORD, T'rammel Creek: July 19, 1934 
im Lownes, 14, 29. 
Nova Scorra.— Moser River, Goldmine 
Brook: July 29, 1939, J. A. C. Nicol, VA AEE BO 
CHESTER BAsIN: Aug. 23, 1939, T. H. Frison 
Meee Hi. Prison, Jr., 4%, 79, 5 nymphs. 
INGRAMPORT: Aug. 22, 1939, T. H. Frison & 
weer. Frison, Jr. 19. 
ONTARIO.—ALGONQUIN Park, Costello Lake: 
June and July, 1938, and June, July and 
August, 1939, W. M. Sprules, 3 4, 99. 
TENNESSEE. — CHIMNEYS CAMP GROUNDS, 
Great Smoky Mountains National Park: July 
@m1939, A. C. Cole, 1é. 
Several nymphs show remnants of anal 
gills as first recorded for claasseni (Frison 
1935a) and also as noted for nymphs of 
decepta Claassen in this paper. Evidently 
such anal gills are to be expected in many 
if not all nymphs of Leuctra. They are 
very easily overlooked because of their 
delicate nature and are probably usually 
lost in handling. 
Leuctra occidentalis Banks (1907) 
Leuctra purcellana Neave (1934) 
Leuctra forcipata Frison (1937) 
Leuctra sara Claassen (19375) 
The study of a large series of specimens 
of any stonefly species is almost certain to 
show that slight variations of some struc- 
tures in most species, and more in others, 
are to be expected. The genus Leuctra 
presents a group of species with very con- 
spicuous morphological differences in most 
of the males named to date and less distinc- 
tive differences in the females. 
One of the first described and a common 
western species of this genus is occidentalis 
Banks (1907). The male of this species 
is one of several having the anal cerci 
strongly sclerotized and peculiarly shaped. 
taxonomic problem arises in determining 
which departures in shape of this structure 
from the typic occidentalis should be con- 
sidered, at least for the time being, as spe- 
cles and which as simply variants. Fig. 
214, B and C shows the character of this 
structure in specimens from three different 
Frison: NortH AMERICAN PLECOPTERA 
259 
states, Oregon, Montana and California, 
respectively. A study of series of speci- 
mens indicates that the observable differ- 
ences in these specimens is of the variant 
order. 
A is} 
CO CeRC! 
Pisses 
Leuctra occidentalis: 
A from Oregon, 
B from Montana, 
C from California. 
Fig. 22.—Leuctra 
purcellana from 
Prairie Hills, 
British Columbia. 3 Cercus 
Fig. 23.— 
Leuctra forcipata 
from Oregon. 
8 
ce 
SO Cerci ip 
£ A 
Fig. 24.—Leuctra sara: A from Massachusetts, 
B from Indiana, C-F from Tennessee. 
