462 
NORTH AMERICAN PLECOPTERA 
Abdomen cylindric, three very fine lines extending the length of the abdo- 
men on the dorsum, the basal segments paler on the venter. Setae pale 
brown. Filaments of the tracheal gills thread-like, long and slender. 
Male. The tenth dorsal segment produced above in a short, straight spine, 
below at the base of the spine, a rounded prominence; the supra-anal plate a 
smaller fleshy lobe attached to the tenth segment below the rounded promi- 
nence (fig. 34). 
Female. The eighth ventral segment with a median depression on the pos- 
terior border. The tenth segment narrow below, produced above in a conical 
process curved upward; the supra-anal plate a fleshy lobe attached to the ven- 
tral surface of the tenth tergite (fig. 35). 
One male from Sante Fe, New Mexico, (P. B. Powell collector), 
VI, 1, 1904, and one exuvia taken at the same time, also an 
exuvia from Pecos, New Mexico, (Piof. T. D. A. Cockerell), 
VI, 1903. Three females, two from Sante Fe, and one from 
Pecos, and an exuvia from each place. All of these specimens 
are at Cornell Univeisity. The exuvia from Pecos, New iMexico^ 
June, 1903, is the described specimen. 
Pteronarcella triloba new species 
Adult 
9 . — Length to tip of wings, 17 mm.; expanse of wings, 33 mm. 
Pale brown. Head as broad as prothorax, lateral anterior margins carinated, 
anterior part of head darker than posterior, a square black spot through the 
ocelli continued just behind the anterior ocellus in lateral horns reaching the 
carinae, carinae very dark brown; on either side posterior to lateral extensions 
of the black spot, a conspicuous pale yellow tubercle; paler areas around the 
inner margins of the compound eyes; occipital area corrugated. Antennae 
dark brown, paler at base. 
Prothorax a little broader than long; sides, front and hind margins about 
straight, angles, rounded, a pale yellow median line, the disc sculptured. 
Meso- and metathorax dark brown, varied with paler on the venter. Tarsi 
darker than the other segments of the legs. 
Abdomen pale above and below, darker toward the tip. Setae dark brown. 
Feynale. The middle area of the eighth ventral segment dark brown, horny, 
narrower at the base than the tip; the tip three lobed, the middle lobe the 
longest, extending beyond the border of the segment, the lateral ones, not 
reaching beyond the border, but continuous with the lateral membranous 
margin (fig. 31). 
One female in alcohol sent to Dr. Needham by C. P. Gillette, 
from Colorado. This is the type specimen. It is at Cornell 
University in the entomological collection. 
Male unknown. 
Nymph unknown. 
