PLECOPTERA NYMPHS OF NORTH AMERICA 75 
General color brown with a wide, yellow median longitudinal 
stripe running the length of the thorax and abdomen, and with 
a narrow yellow stripe on each side of the abdomen. 
Head about as wide as pronotum; a yellow spot in front of the 
anterior ocellus, and a yellow area inside the eyes, extending 
from the base of the antennae to the hind margin of the head. 
Pronotum with a wide median yellow longitudinal stripe; a 
yellow spot on each lateral field, and the lateral margins also 
yellow. Meso- and metanotum similar in coloration to pronotum, 
and, since the adult is apterous, or very nearly so, the postero- 
lateral angles are not prolonged. 
Legs slender and without a fringe of long hairs. 
Abdomen marked with three longitudinal stripes as noted 
above. | 
The nymphs of this species were collected by J. G. Needham at 
Peterson’s Springs, Logan, Utah, July 26, 1926. 
Isoperla signata Banks 
(Plate 20, fig. 198.) 
Length of body up to 10 mm.; antennae up to 5.5 mm.; cerci 
up to 5.5 mm. 
Color yellow with brown markings. Recognized by two dark, 
transverse bands across the head; pronotum margined with 
brown; abdominal segments with the basal half yellow and the 
caudal half brown. 
Head not wider than pronotum; yellow with brown markings 
as follows; a broad transverse band just back of the yellow la- 
brum ; this band connects at the outer margins with another wavy 
band extending across the head in line with the front ocellus, and 
-in the middle extending caudad over the ocellar triangle, leaving 
a yellow spot in the center of the ocellar triangle. In some speci- 
mens the occiput is somewhat darker; hind ocelli a little closer 
to the eyes than to each other; antennae composed of about forty- 
eight segments. 
Pronotum suboval, in some specimens almost rectangular; half 
again as wide as long; angles rounded; the large middle yellow 
area bordered with brown but with the lateral margins also yel- 
low. Meso- and metanotum yellow with brown markings on the 
anterior and posterior margins, and with two longitudinal brown 
stripes on the front wing pads. Legs yellow with a fringe of long 
hairs on the outer margin, most pronounced on the tibiae. 
Abdominal segments one to nine each with the basal half yel- 
