128 THOMAS SAY FOUNDATION 
PLATE 2 
FIGURES 17-32 
17-21 Pteronarcys biloba Newm. 
22-26 Pteronarcella badia- Hagen 
Note the similarity of structure of the mouth parts of this genus 
with Pteronarcys. 
27-32 Peltoperla arcuata Needham 
Note the wide hairy and spiny front leg; the lobe-like appendage 
of the coxa; the wide short, four-lobed labium; the large galea 
of the maxillary palpus with a terminal brush of hairs, and the 
blunt teeth and large molar of the mandibles. 
