18 INJURIOUS INSECTS OF 1909 AND IQIO. 
numbers in former years. Some farmers thought, because they saw 
swarms of locusts in the air, that they must have been the Rocky 
Mountain form; but we saw no evidence of this species, and will 
have to call attention to the fact that the Lesser Migratory Locust, 
as well as other forms, probably, have this habit in common with 
the Rocky Mountain variety. Further, farmers must bear in mind 
that any grasshoppers can be destructive in proportion to their 
abundance. They do not need to come from the Rocky Mountains 
in order to be dangerous. Friends of the writer, entomologists 
who work in Colorado and Montana, stated in 1909 and also in 
Ig1o, that for some time they had been unable to find, in their rep- 
resentative states a trace of the form known as The Rocky Moun- 
tain Locust, Caloptenus spretus; which species, by the way, is very 
closely allied to our common and destructive Lesser Migratory 
Locust. While in the field in Wilkin County, July 6th and 7th, 
1910, we found the Two-striped Locust very abundant, for the most 
part full-grown and some mating. Of the Red-legged and Lesser 
Migratory there were more young than adults. At these dates also 
we occasionally saw quite large swarms high in the air, and coming 
apparently from the West. 
Observations. 
In addition to field work with the farms in r910, we have made 
some laboratory observations which may be of interest, and tried 
experimentally a solution (arsenite of soda) in successful use in 
South Africa. 
Fig. 11. Another view of working hopperdozer. Original. 
1. We have found that young hoppers, freshly hatched, can 
live from four to five days without food under trying conditions— 
a fact which is not particularly encouraging to the farmers. 
