LUCY WRIGHT SMITH 
483 
Arcynopteryx minor Klapdlek 
1912. Arcynopteryx minor Klapdlek, Coll. Selys, 4: 22. 
D istrib ution . — Arctic America. 
cT. — Length of body, 11 mm.; ?, 13 mm.; length of anterior wing of 9 
14 mm. 
“Anterior part of the body almost black, abdomen blackish brown, in the 
female yellowish spots on the venter. In the male the small crown-spot of the 
head joins the occipital bands and widens laterally along the crown suture; 
the sides of the clypeus are yellow-brown. In the female the occipital bands 
are indistinct, the crown-spot greatly reduced, but the sides of the clypeus 
are prominently bordered with yellow-brown. In the male the middle band 
of the pronotum occupies the entire middle field; in the female it is less con- 
spicuous, but the lateral portions show light areas. The under side of the head 
is yellow-brown with a black -brown throat; otherwise the under side is black- 
brown, the venter of the female is lighter. Antennae black-brown, palpi dark 
brown. Legs dark brown, femora narrowly bordered with yellow-brown on 
the ventral edge, and broadly on the dorsal; tibiae yellow-brown for the most 
part. Setae shining bright brown. 
“Head not as long as usual in the species of this genus and a little narrowed 
anteriorly. Eyes moderately large and spherically rounded, behind them 
there are short tempora. Ocelli small, fonning an isosceles triangle; the 
distance between the posterior ocelli is more than half longer than the distance 
from the inner margin of the eyes and from the anterior ocellus (30: 20: 22). 
The crown suture distinct, the occipital furrow deep. Tubercles large, broadly 
oval, equally distant from the posterior ocelli and the inner margin of the eyes. 
The cuticle is fine, but with prominent reticulate wrinkles, and outside the 
tubercles and the M-shaped mark it is studded with scattered pits bearing 
bristles. 
“Pronotum slightly trapezoidal, narrower in front than the occiput, a little 
widened posteriorly (50: 53: 47). Anterior and posterior borders broad, 
convex; sides straight. Middle furrow narrow but deep; the middle area very 
broad, occupying in the first third almost a fifth of the entire breadth, widened 
anteriorly and posteriorly. The structure is similar to that of the head. 
“In the male the wings are greatly shortened, so that the anterior ones reach 
the posterior border of the second segment, and the posterior ones the posterior 
border of the third segment. In both sexes they are conspicuously smoked. 
The network in the tip of the wing occupies the space between radius, its sector, 
and the several branches of the same; but it is comparatively simple and com- 
posed of large, not very irregular cells. The inner inter-radial cell of the fore 
wing is a little more than once and a half as long as its base. 
“In the male the ninth segment is prolonged into a yellow-brown, parabolic, 
subgenital plate, the tenth segment is cleft on the dorsal side with mallet- 
like processes. The other parts show no departure from the usual form. 
“The female subgenital plate is short, semicircular, bright brown, and does 
not appear notched on the posterior margin. 
“A pair in the collection of the Museum of London. 
TRAMS. AM. ENT. SOC., XLIII, 
