472 
NORTH AMERICAN PLECOPTERA 
stylets. In M egarcys signata only the tips of the lateral stylets are 
visible, they are so closely applied to the median one that they 
are very inconspicuous. In this same species the apical network 
of cross-veins is rather irregular, it extends from costa to mediai, 
the costal border does not show a slight concavity at the humeral 
cross-vein, the first third or fourth of the costal area beyond the 
humeral cross-vein is free from cross-veins, the remainder of that 
area is more or less closely traversed with cross-veins; subcosta 
runs into radius beyond the level of the cord; the length of the 
inner inter-radial cell is a fourth greater than its base in females 
and long winged males, and about equal to its base in short 
winged males; cord well developed. Megarcys signata bears gills. 
Megarcys signata Hagen 
1873. Dictyopteryx signata Hagen,, Bull. Geol. Surv. Terr., p. 575. 
1907. Perlodes signata Banks, Cat. Neur. Ins., p. 10. 
1907. Perlodes signata Banks, Can. Ent., 39: 327. 
1912. Megarcys signata Klapdlek, Coll. Selys, 4: 12. 
1900. Dictyopteryx irregularis Banks, Trans. Ann. Ent. Soc., 26: 243. 
1907. Perlodes irregularis Banks, Cat. Neur. Ins., p. 10. 
1907. Perlodes irregularis Banks, Can. Ent., 39: 327. 
1912. Megarcys irregidaris Klapdlek, Coll. Selys, 4: 12. 
Distribution. — Colorado; Mountains of Pacific Coast; Ashford, 
Washington; Biitish Columbia; Wyoming. 
— Long winged, length to tip of wings, 20 mm.; expanse of wings, 30 mm. 
cf. — Short winged, length to tip of abdomen, 16 mm.; expanse of wings, 
18 mm. 
cf . — Length of antennae, 12 mm.; length of setae, 9 mm. 
9 . — Length to tip of wings, 25 mm.; length of antennae, 12 mm.; length of 
setae, 11 mm.; expanse of wings, 42 mm. 
Yellowish-brown varied with yellow, paler beneath. Head flat, triangular. 
Three small ocelli forming an isosceles triangle, the base of the triangle greater 
than the sides, in the male the distance from the inner margin of the eye to 
the posterior ocellus less than the distance between the anterior and posterior 
ocelli; in the female the distances about equal. On either side outside the 
ocellar triangle is a small rather inconspicuous tubercle. Color pattern of the 
head more or less variable; labrum pale yellow, entire clypeus pale, or frequently 
only the middle portion pale with the sides brown, the M-shaped mark varying 
from pale yellow to brown; a pale spot between the ocelli, and three on the 
occipital margin, in some specimens the middle one small and triangular, 
narrowly connected with the crown spot, in other specimens the middle spot 
broadly confluent with the crown spot; the lateral occipital spots more or less 
