September, 1942 
No thoracic, anal or submental gills. 
Nymphal and exuvial records: same data 
as for holotype, 22 nymphs, 13 exuviae. 
I am naming this species in honor of 
my daughter, Patricia Ann, who takes 
great delight in assisting with the collec- 
tion of stonefly adults and nymphs when- 
ever opportunity presents itself and who 
Fig. 88—Nymph of Isoperla patricia, 
light form. 
helped with the collection of the nymph 
and adult specimens from Spearfish, S. D. 
This widely distributed western species 
is easily recognized in the female among 
species of Isoperla, because of its usually 
distinctly notched subgenital plate and the 
peculiar darkening of the posterior part 
of the mesothorax and metathorax. I[so- 
perla fulva Claassen (1937d) has some- 
What the same general color appearance, 
Frison: NortH AMERICAN PLECOPTERA 
315 
but the subgenital plate of the female js 
quite different, and the subanal lobes of 
the male are much shorter and stouter, 
Fig. 89.—Nymph of Isoperla patricia, 
dark form. 
I. extensa Claassen (1937d) has a sub- 
genital plate suggestive of patricia, but in 
extensa this structure is broader at base 
and its general make-up is more similar 
to that of bilineata (Say). 
Although the adult was not actually 
reared from the nymph, the circumstances 
under which nymphs, exuviae and adults 
were taken at Spearfish, §. D., on July 27, 
1940, have enabled me with certainty to 
associate immature and adult forms. The 
vermilion coloring of the abdomen of 
some adult males and indications of this 
coloring in some nymphal males are most 
unusual in this order of insects. 
