21 
rougher barked trees, where they feed upon the foliage, and it is amus- 
ing- to see with what avidity the famished individuals below scramble 
for any fallen leaf that the more fortunate mounted ones may chance 
to sever. This increase in destructiveness continues until the bulk of 
the locusts have undergone their larval molts and attained the pupa 
state. The pupa, being brighter colored, with more orange than the 
larva, the insects now look, as they congregate, like swarms of bees. 
From this time on they begin to decrease in numbers, though retaining 
their ravenous propensities. They die rapidly from disease and from 
the attacks of natural enemies, while a large number fall a prey, while 
in the helpless condition of molting, to the cannibalistic proclivities of 
their own kind. Those that acquire wings rise in the air during the 
warmer parts of the day and wend their way as far as the wind will 
permit toward their native home in the Northwest. They mostly carry 
with them the germs of disease or are parasitized, and wherever they 
settle do comparatively little damage. 
Directions in which the young Locusts travel. — The young insects when 
migrating move, as a rule, during the warmer hours of the day only, 
feeding, if hungry, by the way, but generally marching in a given direc- 
tion until toward evening. They travel in schools or armies, to no par- 
ticular or constant point of the compass, but purely in search of food — 
the same school one day often pursuing a different course from that 
pursued the day previous. On this point the experience of 1875 as 
well as of 1877 is conclusive, though the bulk of the testimony as to 
their actions, when hatching out in the more northern States, is to the 
effect that the prevailing direction taken is south or southeast, while 
in Southern Texas it is jnst opposite, or north. A person traveling 
along a road may often see one army marching in one direction to the 
left and another in the opposite direction to the right, and we have 
repeatedly had such an experience. 
If, from any reason whatsoever, the vanguard of a column changes its 
course, the changed direction is in some way communicated in wave-like 
form to those in the rear. Usually, the front of a column is not easily 
diverted, however, but will pass through such obstacles as open fences 
rather than change course. Sometimes two schools going in different 
directions will cross each other, the individuals of either keeping to their 
particular course and presenting a singular spectacle as they hop past 
one another. 
It is recorded in Europe that few things, not even water, stop the 
armies of the young locusts when on the march, and Dongingk relates 
having seen them swim over the Dniester for a stretch of 1J German 
miles, and in layers 7 or 8 inches thick.* We have had similar experi- 
ence with our own species. In 1875, near Lane, Kans., they crossed the 
Pottawatomie Greek, which is about 4 rods wide, by millions ; while 
* Koppen, loe. cit., p. 43. 
