1924] North A merican Species of Opacijrons and Ptere^nis 133 
Type. — Female; Kukak Bay, Alaska. July 4, 1899, (Kin- 
caid). 
Paratype . — A single specimen from the same collection. 
Limosina (Pteremis) flavifrons n. sp. (Fig. 5). 
Shining black species with head almost entirely reddish 
yellow. Front rather flat, three-fourths as deep as broad; 
bristles black; vertical and occiputal bristles strong; inter- 
frontal bristles very much reduced, in three pairs; antennae 
widely divergent, slightly browned, second and third joints 
nearly equal; arista pubescent, three times as long as antennae; 
face tuberculate between and below antennae, slightly concave 
in profile near anterior margin; clypeus broadly visible from in 
front; cheeks one-third as high as eye when measured atvibrissal 
angle; oral \4brissae well developed; buccal and oral setulae 
minute; eyes piceous, two-thirds as wide as high. Mesonotum 
with two pairs of dorsocentral bristles, posterior pair of middle 
acrostichals longer than the others; scuteUum trapezoidal; 
marginal bristles four; pleurae opaque piceous; upper sterno- 
pleurae with a rather distinct bristle. Legs piceous with front 
coxae, front and middle trochanters, front femora and all tarsi 
ferruginous; front femora silghtly swollen; middle femora with 
a single preapical anterior bristle, middle tibiae with three ex- 
tensor, two on basal third and one on apical third; hind meta- 
tarsi but little thickened, two-thirds as long as nex;t joint. Wings 
slightly smoky extending a little beyond the fourth abdominal 
segment; veins brown; costa setulose on first section, second 
section less than one-half as long as third; second vein reaching 
margin of wing at a point slightly anterior to the inner cross- 
vein; basal section of third vein slightly longer than last section 
of second vein; inner cross vein very narrow; fourth vein pro- 
duced a short distance beyond inner cross vein; outer cross vein 
absent; last section of third vein straight, ending at wing-tip. 
Abdomen longer than thorax; segments equal; dorsum minutely 
pubescent. Halteres fuscous, slightly reduced. Length: 1.25 
mm. 
