4(> 
ill tilt' irri^attMl portions of ('oloia<lo and is due to easily explainable 
(in lunstances. Tlie whole ol the inijja ted portion of the State, coiisist- 
iuji of the \ alleys of streams dcsctMidinj; from the mountains, has been 
seriously affected. The portion of the Tlatte \alley in the neij^hbor 
li<M»d t»f (lre«*l(*y and the valley of the Arkansas in the \icinity of Las 
Animas sceni. however, to have suffered most. l>t*sides this irri«i:ated 
area, a laij^e portion of land alon<^^ the eastern boundary of the State 
above the points to which water may be carrie<l for irri^iation has suf 
fered to sonu' extent, i-larly in May letters from this region statt^l that 
the indications were that e\erything would bedestro.\ ed. In a jieneral 
way it is true that tiie whole tarnjinj? territ<uy of the State may be 
included in the territory very noticeably affected. 
The s)»ecies most concerned have been MvlatKtphis hirittdtna Say, M. 
ftmurrtihnnn J)e(l., M. atUinls J^iley, M. ftnluH Scudd., and Acridium 
fntutdlis Thos., with a noticeable presence of M. diflrrcHtialix Thos. in 
the eastern part of the State. The two first-named species were jjres- 
ent everywhere, and in some pla(;es in almost incredible numbers, 
hivittatiis ([om*j^ l)rol)ably three-fourths of the injury. In the vicinity 
of I'ort Collins I often counted as many as 25 hirj^e, 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 .1/. hirittatus has 
done the most injury, and south of that point M. /emu r-rnhrmii. M. 
/(idus was most abundant in the vicinity of Colorado Springs, but its 
damage was comparatively very slight. .1/. lakinus Scudd. was only 
observed here and in very small numbers. A sweep net full of locusts 
taken in this vicinity yielded (JL si)ecimens, 30 of which were M./cnmr- 
rubrum^ 8 .1/. ((tlanis, 8 M. firdns, 7 .1/. bicitttfins, and the renniining 8 
rei)resenting e(|ually some harmless si)ecies. 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 i>res- 
ent practiced, rnder the present conditions grass and weeds or grain 
si)ring up along the irrigating ditches and are allowed to stand. This 
results from two facts: First, it is necessary to cut the vegetation along 
these ditches by hand if it is cut at all, because in the immediate vicin 
ity of the ditidies the soil is too moist to admit the use of horsi* powei-. 
Second, it is generally sui)poscd that allowing the vegetation to remain 
increases the eflicacy of the ditch by preventing seei)age. As to the 
first of these reasons it may be readily st en that the harvesting of a 
strip of grain or hay fifteen feet wide, which is the usual width of such 
strii)s, would easily rei)ay the farmer because it is the richest growth 
in the whole field. It is thus altogether i)robable that theieturns from 
these strips would L)e greater ju-oportionately than from the remainder 
