SUBFAMILY TRYXALINAE 17 
Mesosternal lobes separated by a space almost linear in narrowest part; meta- 
sternal lobes almost approximate in both sexes Mermeria} 
Mesosternal lobes separated by a space never much longer than broad, generally 
broader than long; metasternal lobes rarely approximate i 
Antennae triquetrous, acuminate, and strongly flattened at base O peta 
Antennae never triquetrous, not acuminate or distinctly flattened at base, 
usually filiform, though sometimes clavate ’ 
Tempora foveolate or plain, not visible from above; face decidedly oblique 
Scutellum of vertex with a distinct median carina, usually stronger 
anteriorly 
Antennae depressed apically, somewhat clavate; supplementary carinae 
accompany the median on head or pronotum or both Eritettix 
Antennae not depressed or clavate but long and filiform; no supple- 
mentary carinae on head or pronotum’ Chloealtis 
Scutellum of vertex with no median carina 
Median carina of pronotum cut much behind the middle; lateral carinae 
of pronotum parallel; foveolae of vertex wanting Dicromorpha 
Median carina of pronotum cut at or near the middle; lateral carinae 
of pronotum more or less arcuate; foveolae of vertex evident 
Orphulella 
Tempora foveolate or plain, visible from above; face less oblique to nearly 
vertical 
Intercalary veins of tegmina strongly developed; median carina of 
pronotum high and sharp, cut plainly before the middle, or very rarely 
at the middle, by the principal sulcus Mecostethus 
Intercalary veins of tegmina not strongly developed; median carina of 
pronotum not high or sharp 
Inner apical spines of posterior tibiae subequal in length 
Antennae filiform Stenobothrus 
Antennae clavate Gomphocerus 
Inner apical spines of posterior tibiae very unequal, the inferior about 
twice as long as superior; median carina of pronotum not cut by 
principal sulcus A geneotettix 
OPEIA McNeill 
The vertex nearly horizontal, shorter than the distance between 
the eyes, convex and a little sulcate behind the lateral carinae which 
are prominent and meet at an angle of about ninety degrees. Median 
carina distinct. Lateral foveolae are small sulci, not visible from above, | 
extending from the ocellus toward the vertex; frontal costa sulcate. 
except at apex. Viewed laterally the face is nearly straight and 
strongly declivent. The antennae are decidedly flattened, especially 
toward the base, regularly acuminate, and shorter than the head and 
pronotum. The pronotum has the disk nearly flat though somewhat 
tectate upon the prozona. The median and lateral carinae are very 
strong and cut by the principal sulcus considerably behind the middle. 
The lateral carinae are nearly parallel upon the prozona but diverge 
somewhat posteriorly from the principal sulcus to the posterior margin 
of the pronotum which is subangulate. The lateral lobes of the pro- 
notum are not quite so high as long and are in large part perpendicular 
although slightly convex above; they bear, below the middle, a nearly 
1Mermeria is included above for the ready identification of M. bivitatta Serv. which, 
although not yet taken in Minnesota, has been taken by us in Iowa near the border of 
Minnesota and may be expected within our area. 
