ARGIA 297 
carina by a pale area equal in width to the black lines themselves, these black 
and pale areas occupy about one-half the surface of the mesepisternum on each 
side. This black area is developed in a pale area which is present on the mesepis- 
ternum as well as on the mesepimeron and the metepimeron, as in moesta. Ab- 
domen darker than moesta, with a narrow pale dorsal longitudinal stripe, nar- 
rowest on 7. The lateral black is carried posteriorly onto 9, usually to its apex; 
10 is pale colored. Sides of abdomen below the black, pale colored. The meso- 
stigmal plates of intruda differ from moesta as follows: in moesta the posterior 
(or superior) lobe of the plate is symmetrical with the border of the plate on 
either side similarly curved, while the anterior (or inferior) border of the plate is 
distinctly concave, the external angle of the plate being correspondingly acute. 
In intruda the posterior border of the mesostigmal plate external to the lobe is 
straighter or less curved than internal to the lobe, resulting in an asymmetrical 
lobe, and the anterior border is straight or slightly convex, resulting in a less 
acute external angle. 
284. Argia moesta (Hagen) 
Hag. ’61, p. 94: Mtk. Cat. p. 48: Wmsn. 712, p. 196: Smn. ’27, p. 12: Garm. ’27, 
p. 89. 
Var: putrida Hag., binotatum Walsh, fantum Hag. 
Length 43-45 mm. Expanse 50-56 mm. Okla., Tex., Ariz. and Calif. 
This is one of the largest of North American species, the typical form is con- 
fined to the southwestern United States and Mexico. 
Male.—Head predominantly black or dark brown, face blue. Prothorax 
brown with a median black area. Middorsal thoracic stripe and carina dark 
brown, occupying about three-fourths of the front on each side, and being thus 
twice as wide as the pale antehumeral stripe. Humeral stripe a black line broadly 
LYE 
A 
sedula tibialis 

united below with another parallel band which reaches to the base of the fore 
wings. Metepimeron and adjoining parts of the metepisternum dark brown or 
black. These black areas of the thorax may become so large that the entire 
thorax is black save a very narrow pale antehumeral stripe, and an abbreviated 
streak on the metepisternum near its middle, just posterior to the interpleural 
suture. Abdomen with segment 2 blackish, with a middorsal yellow spot; 3-7 
reddish brown with a narrow transverse basal yellow ring and a fine longitudinal, 
middorsal yellow line; 8-9 tawny, with a black stripe or a spot on each side near 
’ the base, the stripe extending sometimes nearly to the apex, the inferior margins 
blackish. 
