46 
in the irrigated portions of Colorado and is due to easily explainable 
circumstances. The whole of the irrigated portion of the State, consist- 
ing of the valleys of streams descending from the mountains, has been 
seriously affected. The portion of the Platte Valley in the neighbor 
hood of Greeley and the valley of the Arkansas in the vicinity of Las 
Animas seem, however, to have suffered most. Besides this irrigated 
area, a large portion of land along the eastern boundary of the State 
above the points to which water may be earried for irrigation has suf- 
fered to some extent. Harly in May letters from this region stated that 
the indications were that everything would be destroyed. Ina general 
way it is true that the whole farming territory of the State may be 
included in the territory very noticeably affected. 
The species most concerned have been Melanoplus bivittatus Say, M. 
Jemur-rubrum DeG., AL. atlanis Riley, M. fedus Seudd., and Acridium 
frontalis Thos., with a noticeable presence of M. differentialis Thos. in 
the eastern part of the State. The two first-named species were pres- 
ent everywhere, and in some places in almost incredible numbers, 
bivittatus doing probably three-fourths of the injury. In the vicinity 
of Fort Collins I often counted as many as 25 large, vigorous specimens 
of this species in a square yard along the roadside, and in some places 
they were even more numerous, aS many as 40 being counted in more 
than one case. 
The indications are that north of Colorado Springs W. bivittatus has 
done the most injury, and south of that point M. femur-rubrum. M., 
foedus was most abundant in the vicinity of Colorado Springs, but its 
damage was comparatively very slight. J/. lakinus Scudd. was only 
observed here and in very small numbers. A sweep net full of locusts 
taken in this vicinity yielded 61 specimens, 30 of which were MW. femur- 
rubrum, 8 AM. atlanis, 8 M. fedus, 7 M. bivittatus, and the remaining 8 
representing equally some harmless species. Further south and in the 
Arkansas Valley A. frontalis became more numerous, especially outside 
the region of the foothills toward the Kansas boundary. 
A careful study of the situation in Colorado makes it evident that 
injury from locusts is an invariable concomitant of irrigation as at pres- 
ent practiced. Under the present conditions grass and weeds or grain 
spring up along the irrigating ditches and are allowed to stand. This 
results from two facts: First, it is necessary 0 cut the vegetation along — 
these ditches by hand if it is cut at all, because in the immediate vicin- . 
ity of the ditches the soil is too moist to admit the use of horse power. 
Second, it is generally supposed that allowing the vegetation to remain 
increases the efficacy of the ditch by preventing seepage. As to the 
first of these reasons it may be readily sten that the harvesting of a 
strip of grain or hay fifteen feet wide, which is the usual width of such 
strips, would easily repay the farmer because it is the richest growth 
in the whole field. It is thus altogether probable that the returns from 
these strips would be greater proportionately than from the remainder 
