186 
219 
220 
221 
222 
THOMAS SAY FOUNDATION 
PLATE 31 
FIGURES 219-222 
Perla immarginata Say 
Light spot in ocellar triangle; longitudinal dark stripes on femora; 
basal half of abdominal tergites dark; last abdominal tergite with 
an inverted V-shaped notch; prominent occipital ridge. No caudal 
gills. 
Perla capitata Pictet 
Wavy, dark, transverse band on head through ocellar triangle; 
femora with dark blotches or bands at both ends; caudal half of 
abdominal tergites dark, except the last which is dark on sides only; 
prominent occipital ridge; caudal gills present. 
Acroneuria abnormis Newman 
Dark, hairy; five, more or less distinct, small light spots on head; 
abdomen uniformly dark; legs and cerci with long thick fringes of 
hairs; occipital ridge and anal gills absent. 
Acroneuria lycorias Newman 
Resembles P. capitata but lacks the occipital ridge and anal gills; 
caudal half of abdominal segments dark, basal half more or less 
yellow. 
