SUBFAMILY OEDIPODINAE 33 
ferent species and even in different genera. An interesting point in 
connection with this dimorphism of coloration is the fact that while in 
the Try-xalinae it is the front pair of wings that are subject to varying 
coloration, among the Oedipodinae this variation is confined to the 
second pair. 
In most of the members of this group the males, and in some cases 
the females as well, have the power of “aerial stridulation” by rubbing 
the bases of the tegmina and wings together during flight and this is 
under control of the insect. True stridulation, produced by rubbing 
“the posterior femora against the rough edge of the tegmina, is also 
common here. The members of this subfamily average considerably 
larger than those of the Try-alinae and the insects are in general much 
more active and vigorous both in flight and leaping power, some of 
the species being among the most active and alert of the whole order. 
Economically, the members of this group are generally of little 
importance with us, although two, Dissosteira carolina and Camnula 
pellucida, are sometimes capable of doing great damage to crops. Two 
tribes of this subfamily are found in the Central States and may be 
distinguished as follows: 
Outer margin of hind tibiae with no apical spine next the spurs Oedipodini 
Outer margin of hind tibiae with an apical spine next the spurs Eremobini 
The second tribe is represented by a very large and clumsy species 
Brachystola magna Gir. which, while found in Nebraska and Iowa, has 
not yet been taken in Minnesota. The Oedipodini, however, are well 
represented in our State and may be separated by the following key: 
Interspace between metasternal foramina linear, or longer than broad, in males 
and narrower than mesosternal interspace even in females 
Median carina of pronotum high and arcuate, not cut or but faintly cut by 
the principal sulcus; tegmina subcoriaceous, the apical portion irregularly 
reticulate; wings bright red, orange, or yellow, the ulnar area not cited 
rphia 
Median carina of pronotum not arcuate, cut by the principal sulcus; tegmina 
membranaceous throughout the apical half or at least in the discoidal field; 
wings nebulous yellowish or fuscous; the ulnar area dilated 
Pronotum with the disk tectate and the anterior dorsal margin angulate; 
hind femora without dusky bars on outer face Chortophaga 
Pronotum with the disk flat and the anterior dorsal margin truncate; hind 
femora with dusky cross bars on outer face Encoptolophus 
Interspace between metasternal foramina rather broad; in the male quadrate, in 
the female transverse 
Lateral canthi of metazona crossing the principal sulcus and not intersected 
by it; principal sulcus obsolete or delicate in the lateral lobes : 
Smaller forms; dorsum of pronotum not rugose or tuberculate; wings sub- 
vitreous ; Camnula 
Larger forms; dorsum of pronotum rugose or tuberculate; wings red, orange, 
or yellow with a dark contrasting area Hippiscus 
Lateral canthi of metazona usually intersected by the principal sulcus; often 
obsolescent before it; principal sulcus well developed on the lateral lobes 
Carina of pronotum entire or cut by but one transverse sulcus 
