86 
notum not granulose or tuburculate (except in 
Mestobregma where it is somewhat rugose). 
g. Median carina of the pronotum, prominent, sub- 
cristate; cut by but one (the posterior) trans¬ 
verse furrow; wings in one species black with 
a narrow yellowish marginal band, in other spe¬ 
cies yellow, with a fuscous band across them. Gen. Oedipoda. 
gg. Median carina, small, not prominent, cut in two 
places. 
h. Head elevated, eyes standing high; two sub¬ 
quadrate black spots on the* elytra separated by 
an oblong whitish spot. Gen. Mestobregma. 
hh. Head not unusually elevated; elytra banded 
or sprinkled with minute brown dots. Gen. Trimerotropis. 
aa. Prosternum armed with a distinct spine. Group 3. Acridini. 
b. Elytra and wings always present and always 
as long or longer than 
the abdomen. 
c. Abdomen of the 
male swollen at the 
tip; eyes round or 
oval; not elongate- 
oval. 
cc. 
bb. 
II. 
A. 
AA. 
a. 
aa. 
Gen. Acridium. 
Gen. Pezotettix. 
Gen. Caloptenus. 
Abdomen of the male not swollen at the tip; 
eyes elongate-oval. 
Elytra and wings shorter than the abdomen 
and sometimes wanting; the abdomen of the 
male swollen at the tip. 
Pronotum extending back over the entire ab¬ 
domen, to or beyond its extremity; tarsi with¬ 
out pads between the claws; prosternum in the 
same plane as the sternum. Sub-fam. Tittigin^e. 
Pronotum arched lengthwise. * Gen. Patrachidea. 
Pronotum nearly or quite horizontal. 
Antennae 12 to 14-jointed. Gen. lettix. 
Antennae more than 20-jointed. Gen. Tettigidea. 
Pemarh. —The foregoing table is intended to include only the Illinois 
species, ot Acridulce as far as known; and no attempt is made to set 
forth generic characters further than what is necessary for this purpose. 
It is therefore to be considered as entirely artificial, and for the pur¬ 
pose only of assisting those not acquainted with entomology in deter¬ 
mining species and as an exercise for classes in natural history in our 
common schools. I have endeavored to select such characters as are 
most readily observed, though not always strictly scientific. 
