8 THE ACRIDIIDAE OF MINNESOTA 
Smithsonian Institution, who have aided with kindly advice and criti- 
cism as well as in the verification of certain species, we extend our 
grateful thanks for these and previous favors. To the many friends 
in Minnesota who have contributed in various ways to make our work 
not only possible but also pleasant, we desire here to express our fullest 
appreciation. Among those of conspicuous service to us, both in this 
and in our economic work, were the county officials of Norman County, 
who furnished us with excellent laboratory facilities at Ada; the school 
board of Fergus Falls, Superintendent R. B. MacLean, and J. E. 
Metzger, who aided us in various ways and generously gave the use 
of their high-school building for office and laboratory purposes; and 
Wright Brothers, also of Fergus Falls, who gave us enthusiastic 
cooperation and gratuitously furnished tracts of land for our field 
experiments. Acknowledgments are also due to Miss I. L. Wood, 
artist of the Division, for her work in making drawings. 
ACRIDITDAE 
The Acridiidae constitute that family of the saltatorial Orthoptera 
in which the antennae are shorter than the body, the tarsi three-jointed, 
the ocelli three, and the ovipositor short and never ensiform. It thus 
includes the group commonly called the ‘“‘short-horned” grasshoppers 
and among this group will be found almost all of the species which 
are of serious economic importance, at least within our area. The 
subfamilies may be separated by the following characters: 
Tarsal claws without an ariolum; pronotum dorsally prolonged over the abdomen ; 
tegmina lobiform; insects of small size Tettiginae 
Tarsal claws with an ariolum; dorsum of pronotum never extended over more 
than the basal segments of abdomen; tegmina various; insects of various sizes 
Prosternum not armed with a distinct conical or cylindrical spine, though 
sometimes supplied with a low blunt tubercle 
Face more or less oblique, usually meeting the vertex at an acute angle; 
foveolae usually well developed; wings (in our species) never marked 
with contrasting colors ; ; Tryxalinae 
Face vertical or nearly so and rounded at meeting with vertex; foveolae 
usually obscure; wings usually marked with contrasting colors, though 
pale yellowish in some, and clear in Camnula ; Oedipodinae 
Prosternum armed with a distinct conical or cylindrical spine Acridinae 
SUBFAMILY TETTIGINAE 
The first subfamily, Tettiginae, is made up of small, obscurely 
colored insects found, for the most part, in low open places upon 
either mud or sand. Their colors, blending well with the background, 
render them very inconspicuous and they are commonly passed unno- 
ticed, save by collectors who know their habitat. We have but two 
