DISTRIBUTION AND MIGRATIONS.* * 
BY S. ARTHUR JOHNSON. 
An extended trip, occupying nearly two weeks, was taken in 
the summer of 1904 through that part of Routt county which is 
subject to invasion by the western cricket. Special attention was 
given to securing data and observations on the migrations and 
habits of these insects. 
This species was studied to some extent during the seventies 
and early eighties by the Entomological Commission of the U. S. 
Government.* * 
The observations made at that time confirm the conclusions 
arrived at last summer, that the cricket has its permanent home in 
certain dry hills. They live and prosper there every year, but suc¬ 
cess comes to them as it does to other insects, in liberal proportions 
on certain years. The young have a curious and unexplained habit 
of migrating. These events appear to have only slight connection 
with the abundance of food, though the most numerous bands travel 
the greatest distances. On reaching a desirable pasture they first 
eat ravenously and then resume the march. The latter part of the 
army crowding upon the leaders causes them to move forward. If 
the band is very large, the crowding will give rise to a more rapid 
pace than where the numbers are smaller. 
The migrations appear to have a marked relation to the dis¬ 
tribution of the species. The successful breeding grounds are dry 
hills, which are often at considerable distances from each other. 
Since the insects are unable to fly, it would be next to impossible 
for isolated individuals to reach new territory. This can be, and 
is, accomplished by the armies, which even pass considerable streams 
in their march. 
The homes, so far as we can learn, appear to be of two kinds: 
permanent, where the insects are always more or less abundant; 
and temporary, where the migrating hordes reach a new locality 
* A more detailed account of this phase was presented to the Associa¬ 
tion of Economic Entomologists at their last meeting and will appear with 
the proceedings of that body. 
* * Second Report of the U. S. Entomological Commission, pp. 16 3 - 170 . 
Third Report of the Entomological Commission, pp. 61 - 64 . 
