328 DRAGONFLIES OF NORTH AMERICA 
predominantly orange or yellow. The middle lobe with a transverse black stripe 
along its hind margin, where it joins the hind lobe, from which extends forward, 
on each side, a longitudinal black stripe. Thorax yellow except for the middorsal 
black stripe (.85-.42 mm. wide), and a very narrow black humeral stripe varying 
in width from a mere line to .10 mm. Antehumeral pale stripe wide (.49 —.56 mm.). 
A short black basal streak also present on the upper ends of the second and third 
lateral sutures. Vein Mz, rises nearest the 5th postnodal cross vein in the fore 
wings, the 4th in the hind. Stigma bright yellow. Abdomen with the entire 
dorsum of 1-8 and 10 metallic black, except for narrow interrupted pale basal 
rings on 3-6.9 and sides of 10 blue. Superior appendages longer than 10, re- 
sembling those of vesperum and pollutum. 
Female similar to the male in most respects. The color pattern of the post- 
clypeus varies from almost entirely pale to black with a median yellow spot. 
Yellow areas of the head large, making the black appear as an interocular stripe. 
Prothorax sometimes predominantly black with large yellow spots. Black of 
the humeral stripe never touches the mesostigmal plate (lamina). Abdomen as 
in the male except segment 9 has a large triangular basal black spot on the 
dorsum, covering about three-fourths of the surface, but not reaching the apical 
margin. Segment 10 entirely blue. 
319. Enallagma pollutum Hagen 
Hag. ’16, p. 83: Mtk. Cat. p. 61: Calv. ’19, p. 378. 
Length 32 mm. Expanse 36 mm. Fla. 
Le Dsle Ds 
pollutum sulcatumn signatum 
One of the yellow-black species occurring commonly in ponds and swamps 
where there is an abundance of standing vegetation. Male. Face yellow, a fine 
black line at the base of the labrum. Postclypeus usually entirely black, oc- 
casionally with one or two median yellow spots. Pale frontal transverse band 
narrow, not reaching the middle ocellus. Base and first segment of the antennae 
yellow. Vertex black except for a pair of yellow spots between the lateral and 
the median ocelli. Postocular spots linear and very narrowly connected with 
the pale postocellar stripe, but not connected with the pale color of the rear of 
the head. Anterior and posterior lobes of the prothorax yellow. Middle lobe 
predominantly black, with only the sides and two lateral spots yellow. Thorax 
with the pale antehumeral stripe narrower than the black humeral. Middorsal 
dark stripe .53-.63 mm., pale antehumeral .25-.28 mm., dark humeral .37—.42 
mm. wide. Third lateral suture with a black stripe on the upper five-sixths o1 
more of its length. Dorsum of abdominal segments 1-8 and 10 entirely metallic 
black. Segment 9 entirely orange. Superior appendages longer than 10 and 
though irregular, are not bifid. 
The female is similar to the male. The lateral end of the mesostigmal plate 
is margined with the black of the humeral stripe. Width of black middorsal 

