ISCHNURA 343 
vegetation. Sometimes in low marshy spots, in fields, where there is no 
open water at all, they occur commonly. Unlike the larger Enallagmas 
the adults seldom venture out over the open water, but seem well con- 
tented to spend their lives flitting about among the grasses, lakes, 
swamps and ponds. Copulation takes place in these situations, some- 
times on the wing, but generally while at rest on the stems and leaves of 
the aquatic vegetation. The male does not, as a general thing, accom- 
pany the female while ovipositing. The eggs are laid singly in the stems 
and leaves of the surrounding plants. The nymphs occur in the shallow 
waters of the same types of habitat that the adults frequent. 
The males of Ischnura may be characterized as follows: Mouth parts 
genae and postgenae, pale. Labrum bluish-green with a broad black 
basal band. Postclypeus black; anteclypeus pale. The top of the head 
predominantly black; the pale transverse frontal band on the vertical 
portion of the frons narrow; the postocellar stripe vestigial or generally, 
entirely wanting; and the postocular spots are extremely small, round, 
and never connected with any other pale area of the head. The pale 
antehumeral stripe of the thorax is variable, in most of the species it is 
entire, and whether wide or narrow, it is of equal width throughout its 
length; in others it is interrupted in its middle length by a fusion of the 
black middorsal and humeral stripes, resulting in an anterior and a 
posterior pale spot, or spot and abbreviated stripe, on either side of the 
mid-carina; in still other species the antehumeral pale stripe is entirely 
absent, the dorsum of the thorax being solid black. The coloration of 
abdominal segments 8-9 are of specific value, but are unfortunately 
somewhat unconstant. On the apical margin of the dorsum of abdo- 
minal segment 10 there is an elevated, bifid process, differing in size and 
shape in the various species, but never as long as segment 10, as it is 
in the genus Anomalagrion. 
In both males and females vein Mz arises between the 3rd and 4th 
postnodal cross vein in the forewing, and the 2nd and 3rd in the hind. 
Setae of the front row on the tibia are all short. 
A ventral spine on the apical margin of abdominal segment 8 in the 
female is variable generic character. 
Those species which always possessing this spine are barbert, kelli- 
cotti, cervula and verticalis. Those which never possess it are perparva, 
posita and prognatha. Those that may or may not have it are credula, 
demorsa, denticollis, erratica, gemina, and ramburiit. Unknown with 
respect to it are damula and utahensis. 
The mature females of certain species exhibit dichromatism. That is, 
in fully matured specimens there are two kinds of females, separated 
