82 THE ACRIDIIDAE OF MINNESOTA 
any series of favorable seasons becomes abundant, especially in the 
more open parts of the State. Large areas of wild hay land and other 
uncultivated tracts give sufficient undisturbed breeding-grounds to 
supply a source from which this pest must surely appear year after 
year until conditions shall be changed. The outlook in this as in sev- 
eral adjoining states is that so long as this and allied forms are allowed 
favorable conditions, there will continue to be danger of more or less 
serious outbreaks, meaning in every case great loss to the farmers of 
the area. Without entering into details of methods by which these 
insects may be controlled, we may say that a thorough system of culti- 
vation of the land, with a rotation system in which a thoroughly culti- 
vated crop shall always follow cereals, presents the real cure for these 
pests. Temporary means of relief and of reduction of numbers are 
to be found in the system of spraying with sodium arsenite, and in 
the use of hopper-dozers, when of proper design. These economic 
phases are more fully treated in the Fourteenth Report of the Minne- 
sota State Entomologist for 1911 and 1912, to which reference should 
be made. The species is somewhat variable in the color of the hind 
tibiae and although these are commonly of varying shades of red, yet 
we have taken specimens with the hind tibiae yellowish, greenish, or 
rarely deep blue in color. Since the insect is generally and uniformly 
distributed over this and surrounding states no locality records are 
here included. 
Melanoplus spretus Uhl. 
Melanoplus spretus has been more widely and more carefully 
studied and has been the subject of more entomological thought and 
literature than any other Orthopteron. As the much-dreaded Rocky 
Mountain locust it has become known, by name at least, over a large 
part of the northern United States. It has been fully described and 
discussed in numerous publications, and since it is today apparently 
extinct, or practically so, no detailed description will be given here. 
We may say that this insect was never truly a native of our State and 
never persisted for any long period within our borders. It came at 
times, in countless millions, in its migrations from its breeding-grounds 
farther west, and the story of these grasshopper scourges of the early 
days, while now but a matter of historv to many of us, are still vividly 
recalled by the older people, who suffered under those veritable plagues 
of locusts. It is hard today to realize the enormous numbers in which 
these voracious pests appeared and it is, perhaps, harder to grasp the 
full significance of what such an invasion meant to the scattered fam- 
ilies of those early days, with their small fields and their woeful lack 
of means of communication and transportation. 
