3g 
MIGRATORY LOCUSTS OR GRASSHOPPERS. 
Among the worst pests known are insects of this kind, and it 
is not strange that grasshopper-plagues are never forgotten by 
persons that have experienced them. The losses caused to 
farmers and gardeners, in fact to all classes of people, have 
been so enormous in the past, that a repetition of such a plague 
is greatly to be dreaded. In the past the Colorado or ‘‘Hateful 
Locust” (Melanoplus spretus Uhl.),was the only species that in- 
vaded our state in such immense armies that the ground was 
covered with them, and that every green blade and leaf disap- 
peared almost ina night, Since 1885 but few specimens of this 
locust have found their way into our state; those that found a 
lodgment in Otter Tail county, after causing much damage, 
were destroyed in 1889 by a system of thoroughly plowing all 
soil in which eggs had been deposited. Once more, in 1890, 
specimens of this insect reached our state, and located with two 
other migratory species in the central parts of the Red River 
Valley, extending from Crookston to north of Hallock. This 
swarm, which passed over Crookston on Aug. 14th, fiying in a 
south-easterly direction, was partly destroyed in the same sea- 
son by dropping in the upper Rice Lake, in the White Harth 
Indian Reservation. Buta large number of the heavy females, 
filled with eggs, had dropped to the ground, and had deposited 
eges in the more sandy portions of Polk, Marshall, and Kitt- 
son counties. Here the young locusts hatched in large numbers, 
but were killed by plowing and the use of ‘‘hopperdozers” in 
the following spring, so that none of the Colorado species re- 
mained, and only a few of the lesser migratory locust and the 
pellucid locust, which came with the former. There can be 
but little doubt that a few specimens of the latter two species, 
instead of being killed in the lakes, continued their flight, and 
lodged near Duluth, where they deposited eggs. In conse- 
quence of this a few specimens were found in Duluth in the 
early summer of 1891, and some of them were mailed to the 
writer from that place. In 1892 they became very numerous and 
caused some damage to the lawns and gardens. In the same 
year a parasite, the Tachina fly, Fig. 19, became very numerous 
in the infested region, and killed the great majority of the in- 
truders. Yet enough remained to deposit a large number of 
