4 THOMAS SAY FOUNDATION 
tomology the food habits of the nymphs are described as ‘‘ear- 
nivorous.’’ (Imms, Handlirsch, et. al.) This misconception has 
undoubtedly been due primarily to the fact that the large and 
more strikingly colored nymphs of the genus Perla and Acro- 
neuria are voracious carnivores, and these are the nymphs which 
are most frequently observed and collected. The European work- 
ers (Lestage, Samal, Schoenemund, Mertens, et. al) have reported 
from time to time that certain of the Plecoptera nymphs are 
herbivorous and feed on algae and other plant products. In 
America, Newcomer (32) was the first to report that some of the 
adults of Taeniopteryx feed upon leaves and buds, and at times 
become injurious to young fruits. Wu (57) in his paper on 
Nemoura reports the nymphs to be feeding on vegetation, par- 
ticularly on decaying leaves. Frison (6) found that all of the 
nymphs of Leuctra, Taeniopteryx, and Allocapnia, which he 
studied, were herbivorous. He found also the adults of Taeniop- 
teryx and Allocapnia feeding on Protococcus and was able to 
keep them alive for extended periods of time only when he sup- 
plied them with Protococcus and water. Some twelve years ago 
Dr. C. H. Kennedy studied the stomach contents of Pteronarcys 
nymphs in Ithaca, New York, and found only plant material 
present in the digestive tract. 
A more detailed study of the entire order indicates that, of the 
five North American families herein recognized, the nymphs of 
four (Pteronarcidae, Peltoperlidae, Nemouridae, and Capni- 
idae) are herbivorous, and that in only one family (Perlidae) are 
the nymphs essentially carnivorous. In the herbivorous type 
(Pteronarcidae, Peltoperlidae, Nemouridae, and Capniidae) the 
mouth parts are adapted for manipulating plant material. The 
labrum is longer and narrower than in the carnivorous type; it 
possesses no distinct epipharynx, and the clypeal suture is dis- 
tinct. The mandibles are wide and massive, and are provided with 
four to six short, mostly blunt, teeth, and following these teeth 
there is a well-developed molar for grinding the plant material. 
The maxillae, likewise, are fairly massive, the lacinia is wide, and 
more or less scooped on the inside, and bears at the apex two or 
three short blunt teeth. It is well fitted for wafting plant material 
into the mouth. The galea is strongly developed, and is usually as 
long, or nearly as long, as the lacinia. The maxillary palpus is 
much stouter than in the carnivorous type. The essential charac- 
teristics of the labium are the almost-equal development of the 
Ea and the paraglossae, and the stout and shortened labial 
palpi. 
