D8 THOMAS SAY FOUNDATION 
The sexes are easily distinguished, because in the male the su- 
pra-anal process is produced beyond the tenth tergite in the form 
of a tubercle which may be almost as long as the tenth tergite. 
The mouth parts are similar to those of P. aestivalis. Labrum 
about three times as wide as long; mandibles with five sub-equal 
teeth, followed by a fringe of hairs. Maxillae: cardo and _ stipes 
long, the stipes about as long as the lacinia; lacinia wide at the 
base and gradually narrowing toward the tip, with two long teeth, 
the second tooth a little more than half as long as the apical one, 
and, following the second tooth, only one or two hairs on the inner 
margin; galea about half as long as lacinia and tipped with a few 
hairs. Labium longer than wide; glossae short, triangular; para- 
glossae large, hairy; both glossae and paraglossae attenuated at 
the tips which are beset with papillae. Hypopharynx broadly 
rounded. 
Described from nymphs collected at Neversink, New York, May 
11, 1929. P. R. Needham. 
The nymphs are quite mature and the structure of the genitalia 
indicates that they belong to verticalis. 
Genus ALLOPERLA Banks 
Small yellowish-brown nymphs measuring, when fully grown, 
7 to 13 mm. in length. Body somewhat depressed. Head a little 
wider than pronotum; brownish, with the median area usually 
somewhat darker; three ocelli placed in an almost equilateral tri- 
angle; front ocellus smaller than hind pair, which are usually 
closer to the eyes than to each other; surface of head quite smooth 
but with feeble pilosity ; sutures on head not very distinct; no oc- 
cipital ridge; antennae about one-third as long as body and com- 
posed of forty to fifty segments. 
Pronotum wider than long; suboval, with the angles broadly 
rounded; a narrow marginal groove, which in some species ap- 
pears as a narrow darker line extending around the entire prono- 
tum; surface of pronotum with long hairs, especially at the outer 
angles. In the mature nymphs the pronotum often shows the 
darker markings of the developing imago. 
Meso- and metanotum with the wing pads very wide and with 
the lateral margins broadly rounded; surface quite smooth, and 
thickly covered with brownish hairs. Legs somewhat flattened and 
covered with many hairs; a thin fringe of hairs is usually present 
on the tibiae but not on the femora; first and second tarsal seg- 
