78 THOMAS SAY FOUNDATION 
Ithaca, N.Y.; Elkhart, Ind.; Lake Forest, Ill.; W. Ottawa, IIL; 
Potomac R., Brunswick, Md. 
Genus ATOPERLA Banks 
Length of body not over 12 mm. The nymphs of this genus 
possess copious thoracic gills but no anal gills. The lacinia of the 
maxilla terminates in a single tooth; posterior ocelli distinct, 
and anterior ocellus either entirely absent or indicated by a 
small depression. 
In general appearance Atoperla is similar to Perlinella but is 
smaller in size and has no anal gills. 
Atoperla ephyre Newman 
(Plate 8, figs. 129-134; plate 22, fig. 200.) 
Length of body up to 9 mm.; antennae up to 3 mm.; cerci up 
to 3 mm. 
These small brownish nymphs possess long gill tufts on the 
thorax, have only two distinct ocelli, set much farther apart 
than in Neoperla, and have the lacinia unidentate. 
The specimens which I have are old and shriveled, hence there 
is some question whether the rather uniform brownish color repre- 
sents the true color of fresh specimens. 
Head slightly wider than pronotum; hind margin of eyes in 
line with posterior ocelli, which are as close to the eyes as to 
each other; front ocellus either absent or only indicated by a 
small depression ; occipital ridge absent. 
Pronotum nearly twice as wide as long; hind angles very 
broadly rounded, front ones more narrowly rounded; marginal 
groove continuous all around; surface only slightly rugose. Wing 
pads considerably prolonged; broadly rounded at the tips. 
Legs flattened ; femora and tibiae with a fringe of long hairs; 
first and second tarsal segments very short, subequal; third seg- 
ment about four times as long as the two preceding combined. 
Abdomen brownish, slightly depressed. Cerei of about twenty- 
five segments. Labrum about three times as wide as long, with a 
fringe of hairs on the front margin. Mandibles rather narrow, 
asymmetrical; each with four rather large teeth followed by a 
fringe of hairs. Maxillae: lacinia unidentate; inner margin with 
six or seven very stout hairs, the one next to the apical tooth 
so large as to suggest a second denticle. Galea slender and shorter 
than lacinia. Labium; glossae very short, triangular; paraglossae 
large and widened toward the tip. 
