Claassen, Peter W.  <br/><br/>
Plecoptera nymphs of America:  (North of Mexico) / 
by Peter W. Claassen. 
 - Springfield, Ill.:  Charles C. Thomas,  1931. 
 - 195 p. :   ill. ;   22 cm. 
<br/><br/> Published for The Thomas Say Foundation. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Stoneflies--Mexico<br/>Stoneflies--America