134 THOMAS SAY FOUNDATION 
PLATE 5 
FIGURES 66-82 
66-70 Acroneuria abnormis Newm. 
71-76 <Acroneuria pactfica Banks. 
77-82 Perla immarginata Say. 
The mouth parts of these three species are very similar and.do not 
show characters sufficiently different to be useful in specific deter- 
mination. 
