190 
227 
228 
229 
230 
THOMAS SAY FOUNDATION 
PLATE 33 
FIGURES 227-230 
Acroneuria arida Hagen 
Striking color pattern; wide pronotal flange; occipital ridge absent; 
small anal gills; abdomen nearly uniformly brown. 
Perla media Walker 
Short, broad flattened; dark brown to blackish; hairy and usually 
with a dirty appearance; heavy fringes of long hairs on legs; ab- 
domen brown. 
Taeniopteryx nivalis Fitch 
Light strip on body; diverging wing pads; coxal three-segmented 
gills; very long slender antennae and cerci. 
Perla hastata Banks 
Mottled areas on head; large maxillae; rather square pronotum; 
color olivaceous; slender legs; no gills. 
