478 
NORTH AMERICAN PLECOPTERA 
the third pair, a little lateral and anterior to the base of the fore legs, the fourth 
and fifth pairs in the same relative position on the ineso- and metathorax. 
Female. Abdomen browm above and below; vulvar lamina paler, large and 
shining, produced nearly across segment nine; the posterior border in the form 
of a W with rounded angles (fig. 49). 
Described from a single type specimen from California. This 
is in the entomological collection at Cornell University, Ithaca, 
New York. 
Male unknown. 
Nymph unknown. 
Arcynopteryx vagans new species 
Adult 
Distribution . — Nevada County and San Diego, California. 
(J'. — Long-winged. Length to tip of wings, 16 mm.; expanse of wings, 26 
mm. 
cf . — Short-winged. Length to tip of wings, 14 mm.; expanse of wings, 21 
mm. 
cf. — Length of antennae, 16 mm.; length of setae, 11 mm. 
Yellowish-brown varied with yellow markings on the head and thorax, and 
paler beneath. Head triangularly produced; three small ocelli placed in an 
isosceles triangle, its base greater than the sides, the distance from the inner 
margin of the eye to the posterior ocellus greater than the side of the triangle 
but not as great as the base. On either side of the ocellar triangle, a glo.ssy, 
dark brown, oval tubercle, somewhat nearer the posterior ocellus than the inner 
margin of the eye. M-shaped mark conspicuous. Labrum whitish. From 
the tubercle a broad, dark fuscous area extending laterally to the eye and 
encircling its inner margm with a narrow band which spreads out posteriorly, 
covering the entire occipital region behind the eye, anteriorly the band broadens 
and runs along the lateral border of the frons and clypeus. In one specimen 
at the level of the anterior ocellus, a transverse bar connecting the dark areas 
of either side, in the same specimen, from the tubercle a posterior extension, 
rumiing slightly diagonally inward to the occipital margin. Three pale yellow, 
coarsely corrugated spots on the posterior border of the occiput, a small median 
triangular one with its apex directed forward, and on either side close to the 
dark fuscous areas behind the eyes, a large oval spot. Antennae brown, stout, 
as long as the body; palpi brown; under side of head, pale. 
Pronotum trapezoidal, anterior border wider than the posterior and wider 
than the occiput, sides and posterior margin straight, anterior margin convex, 
front angles rather sharp, hind angles rounded off; a broad, median, yellow 
stripe, conspicuous, glossy brown, embossed markings on the lateral fields. 
Meso- and metanotum dark brown with the median yellow band of the pro- 
notum continued upon them. The entire venter of the prothorax pale with 
darker markings. Legs yellowish-brown ; bases and tips of femora and tibiae, 
