296 DRAGONFLIES OF NORTH AMERICA 
antero-lateral spot on 6; segment 7 with the dorsal half black except a narrow 
basal band, and having a small latero-apical spot in the ventro-apical angle of 
the segment; segments 8-9 with more or less black on the lower sides. 
Female.—Colored brown with the black markings on the head and thorax 
as in the male. The abdomen with lateral stripes on segments 2-9, those on 
segments 7-8 more or less confluent with their mates across the middle line. 
Segments 2-8 with latero-apical oblique spot on the lower apical angle of the 
side. Segments 2-7 with a narrow apical ring. 
282. Argia immunda (Hagen) 
Hag. ’61, p. 93: Mtk. Cat. p. 47: Wmsn. ’14, p. 415. 
Length 30(<)-36( 9) mm. Expanse 40-52 mm. Tex. 
Male.—Color, blue or violet and black. Face and rear of head pale, a black 
bar through the ocellar region. Prothorax black on the dorsum, sides pale. Pale 
antehumeral stripe from three-fourths to one and a half times as wide as the 
black middorsal. Humeral stripe forked in its upper third, never wider than 
the pale antehumeral. Abdomen blue, the following black: segment 2 each 
side with a dorso-basal spot, a large rounded spot near the apex, and an oblique 
inferior streak, the latter two or all three sometimes united; 3-6 each side with 
a postbasal streak and the apical third, the postbasal streaks from one side may 
unite with their fellows from the other across the meson, but never with the 
apical black; 7 entirely except a pale basal ring; an inferior stripe the length 
of the segment on 8-9. 
Female.—Similar to the male. Differs as follows: Humeral stripe hardly 
more than a line throughout. Segment 7 like 6, but with the postbasal streak 
and apical black usually united; 8-9 entirely pale, unspotted. 
283. Argia intruda Williamson 
Wmen. ’12, p. 200. 
Length 38-42 mm. Expanse 54-60 mm. Okla. 
This species of Argia is closely related to moesta, whose large size and general 
characteristics it shares. 
Male.—Head dull pale brown, rear of head black above, pale brown below. 
Thorax pale brown, black as follows: a middorsal thoracic stripe, one either 
side occupying one-half of the front; a spot on the front against the hum eral 
suture where it meets the mesinfraepisternum, and another above the caudal 
end of the second lateral suture; a faint line on the third lateral suture widened 
into a small spot on the rear end; in some specimens the two large black spots 
on the mesepimeron become narrowly or even broadly connected. Abdomen 
black above, pale brown on the sides of all segments but 7; pale narrow blue 
rings on 3~7; a longitudinal middorsal stripe absent or very reduced on 6-7; 
9-10 variable, generally gray or light brown excepting the lower lateral margins 
and ventrally, and a black lateral spot on the middle of 9, this spot on 9 may be 
wanting or elongate. Abdominal appendages similar to moesta, but the inferiors 
are longer than the superiors, and are terminated by a large rounded pale 
tubercle. 
Female.—Similar to the male. Darkest thoracic pattern: a black line on 
either side of the middorsal thoracic carina, separated from the black middorsal 
