SUBFAMILY OEDIPODINAE 59 
near the base, while in Psinidia they are whitish with a dark ring near 
each end and usually a broad one near the middle. There is also a 
difference in the maculation of the tegmina, which in Mestobregma 
have in the costal field two squarish areas separated by an oblong light- 
colored spot, while in Psinidia the area is marked with numerous small 
spots. We have found that in the field the wings of Mestobregma are 
subject to considerable variation in coloration, ranging from the typical 
form with the basal third lemon-yellow and a narrow, curved, fuscous, 
median band, to forms in which the basal third is whitish or trans- 
parent and with no trace of a curved fuscous band. This variation 
appears to be entirely individual and in no way influenced by the age 
of the insects, as we have found the different forms in specimens still 
soft from the final moulting and in ragged and worn specimens late 
in the season; neither does environment appear to influence the colora- 
tion as we have noted them alike on clear sand, with such plant forma- 
tions as Grindelia, Froelichia, and Croton, and also in open woodlands 
undergrown by grasses. In Minnesota we have taken this species at 
Fergus Falls, Granite Falls, Redwood Falls, Pipestone, Ada, Hawley, 
Bemidji, Hibbing, Vermillion Lake, Duluth, Hinckley, and Mahtomeds. 
PSINIDIA Stal. 
Small and slender insects with the head large and prominent and 
the occiput strongly elevated; disk of the vertex broad posteriorly, 
narrowing rapidly anteriorly, quite strongly declivent; lateral carinae 
sharp, nearly converging in front; foveolae rather small and sub- 
circular; the frontal costa sulcate throughout, very narrow above and 
gradually expanded below. Antennae long, especially in the males, 
the joints of the basal half strongly flattened and with the edges rising 
somewhat above the center. Pronotum with the disk nearly flat, granu- 
late, the median carina distinct and twice cut by the sulci; front margin 
of the pronotal disk truncate, hind margin acute-angled: lateral ca- 
rinae distinct on the metazona and weaker on the prozona; lateral 
lobes deeper than broad, front margin straight and posterior margin 
somewhat concave, inferior margin arcuate and quite strongly ascend- 
ing anteriorly. Tegmina rather narrow, exceeding the abdomen in 
both sexes and strongly coriaceous in the basal half. Inner wings 
red at base, the arcuate dark band submedian and considerably ex- 
panded posteriorly. Hind femora reaching or surpassing the tip of 
the abdomen; hind tibiae annulate. This genus is represented by one 
species, which is found throughout eastern Canada and the United 
States. 
