PLECOPTERA NYMPHS OF NORTH AMERICA 53 
New York: Ithaca; Dansville; Wilmington; Moffitsville; Alle- 
gany Co.; Montgomery, Mass. 
Perla aestivalis (?) Needham and Claassen 
Length of body up to 11 mm.; antennae up to 5 mm.; cerci up 
to 5 (?) mm. 
General color yellowish brown, with the outer margin of the 
pronotum dark, and with the basal half of the abdominal ter- 
gites darker than the caudal half. Head a little wider than pro- 
notum, quite smooth, and almost equally brown all over; ocelli 
large, the hind ones nearly twice as close to the eyes as to each 
other; occipital ridge absent; antennae composed of about fifty 
segments. Pronotum about twice as wide as long, transversely 
oval, with the angles broadly rounded; surface nearly smooth; 
marginal groove dark and very distinct all around. Wing pads 
long, set far apart, and lying almost parallel with the body. 
Legs long, slender, and not much flattened ; a fringe of long hairs 
on the outer margin; femora with rather few hairs on the upper 
surface; third segment of tarsus very long, about half as long 
as tibia; tarsal claws with a prominent, sharp, basal tooth. Ab- 
domen somewhat flattened, smooth, and with a fringe of spinules 
on the posterior margin of each tergite; cerci with the tips 
broken off, but one of the nymphal skins shows twenty segments, 
and the total is probably twenty-five to thirty. 
Gills absent. 
Mouth parts of the carnivorous type. Labrum three times as 
wide as long; front margin with a fringe of long hairs. Mandi- 
bles rather slender, with four unequal teeth, followed by a 
fringe of long hairs, and beyond this fringe the mandibles some- 
what excavated or broadly notched. Maxillae: cardo very short; 
stipes as long as lacinia; lacinia broad at base, bidentate, the 
second tooth only half as long as the long terminal one and fol- 
lowed by only a few long hairs; galea feebly developed, eylindri- 
eal and only about half as long as lacinia; maxillary palpus 
longer than lacinia, its apical segment very slender. Labium 
longer than wide; glossae short, triangular, and produced into 
blunt tubercles which are closely beset with papillae; para- 
glossae large, hairy, directed inward, and bearing at the tip 
tubercles similar to those of the glossae; labial palpi extending 
far beyond paraglossae. Hypopharynx rounded and closely beset 
with short stiff hairs. 
