PLECOPTERA NYMPHS OF NORTH AMERICA 105 
Head a little narrower than pronotum; entire occiput covered 
with mottled brown marks; there is also a brown spot each side 
of the ocellar triangle at the base of the antennae, and another 
in front of the anterior ocellus; hind ocelli at least twice as 
close to the eyes as to each other; surface very feebly pilose; 
antennae long, slender, brown at the base and lighter toward the 
tip; of about seventy-five to eighty segments. 
Pronotum a little wider than long, slightly widened posteriorly ; 
angles rather broadly rounded; a broad, median, yellow stripe, 
on each side of which the rugose dises are of a darker brown 
color, or else there are dark markings upon a lighter background ; 
meso- and metanotum brownish; metathoracic wing pads di- 
rected away from the long axis of the body, so that the hind 
margins are almost at right angles to the body. 
Legs somewhat flattened; tibiae with a sparse fringe of long, 
fine hairs on the outer margins; first and second tarsal segments 
about equal in length, the two together at least as long as the 
third segment. 
Abdomen nearly cylindrical, more or less uniformly brownish, 
but in more mature nymphs, the mottled appearance of the de- 
veloping adult may be seen through the chitin; ventral surface 
of body light in color. There are three pairs of segmented, tele- 
scopic, filamentous gills attached at the mner base of the coxae 
as in T. mvals. 
The sexes in this species are readily separated. In the female 
the ninth abdominal sternite is hardly produced at all; the tenth 
tergite is broadly rounded on the posterior margin. In the male, 
the ninth sternite is somewhat produced rearward, and the tenth 
tergite bears in the center of the posterior margin a projected 
lobe in which the developing supra-anal process lies. In the 
mature nymphs, the detailed genital structures can readily be 
observed through the chitin, especially after the specimens have 
been in alcohol for some time. Likewise, the tooth on the femora 
ean readily be seen in the male. The smaller size and the relatively 
lighter color distinguish this species from 7’. nivalis. 
Plummer’s Island, Md.; Washington, D.C. 
Taeniopteryx parvula Banks 
Male. Length of body up to 7 mm.; antennae up to 5 mm.; 
cerci 4 mm. 
General color yellowish brown with some darker mottlings on 
the head and some more or less indistinct darker markings on the 
rest of the body. 
