PLECOPTERA NYMPHS OF NORTH AMERICA 65 
Mouth parts are of the carnivorous type and are described un- 
der P. frontalis. 
Paraperla frontalis Banks 
(Plate 7, figs. 100-105; plate 10, figs. 167-168; plate 18, fig. 193.) 
Length of body up to 18 mm.; antennae up to 7.5 mm.; cerci 
up to 6 mm. 
This species is recognized by its slender form, absence of gills, 
long head with small eyes which are set far forward, a trans- 
versely oval pronotum, and broadly rounded wing pads. 
General color yellowish with a little darker color around the 
margin of the pronotum. 
Head about as wide as long; three small ocelli placed in an 
equilateral triangle; eyes very small and placed far forward so 
as to be nearly in line with the front ocellus; occipital ridge not 
clearly marked; surface quite smooth; antennae with about 
seventy rather short segments, the apical segments not more than 
twice as long as wide. 
Pronotum transversely oval, the sides and front and hind 
margins rounded; marginal groove extending all around the 
pronotum; surface nearly smooth; wing pads rounded on the 
sides and at the tip. Legs with a sparse fringe of hairs on the outer 
margins of femora and tibiae; first and second tarsal segments 
very short, subequal, third segment about four times as long as 
one and two combined. Abdomen nearly cylindrical; tenth tergite 
medially produced into a rounded lobe; cerei rather short and 
stout, gradually tapering toward the tip; about twenty-three seg. 
ments, each segment terminating in a whorl of hairs. 
Mouth parts. Labrum about four times as wide as long; the 
anterior margin fringed with long hairs. Mandibles slightly asym- 
metrical, each with four sharp teeth followed by a brush of long 
hairs. Maxillae; first segment of maxillary palpus about as long 
as wide; second segment as long as first; third segment a fourth 
again as long as one and two combined; fourth segment three- 
fourths as long as the third; and fifth a little more than half as 
long as the fourth, and bearing at the tip a few short hairs. 
Lacinia rather wide at base and ending in a large incurved tooth 
which bears a smaller tooth midway on the inner margin and a 
comb-like row of stout hairs. Below the base of the large tooth the 
inner margin of the lacinia is fringed with hairs. Galea rather 
slender, consisting of a single segment which reaches to the 
middle of the lacinial tooth, and which bears at the tip, a few 
