160 REPORT UNITED STATES ENTOMOLOGICAL COMMISSION'. 
valley of the Upper Big Horn region, were not included in the Per- 
manent Region, for want of sufficient data. The boundary of the per- 
manent breeding grounds has then to be extended considerably to the 
west, so as to include the patch in Northern Ctah and the region in 
Idaho lying south of Virginia City, Montana. This makes tlu- Perma- 
nent Region an uninterrupted rudely triangular or oval area, widest on 
the Northern United States boundary line, and narrowing southward, 
the apex of the triangle or smaller end of the oval resting near the 
southern line of Colorado, on or near the 37th parallel of latitude 
North of the 14th parallel the Permanent Key ion has been extended 
eastward to a line nearly identical with the eastern border of the 
Plateau of the Coteau of the Missouri, extending northward through 
the Turtle Mountains and to the region lying a little west of Manitoba. 
In New Mexico, the region periodically visited has been extended 
southward to Fort Craig, New Mexico, and made to include the north- 
eastern section of Arizona. 
These alterations have been made in the colored map of the arable 
lands, etc., accompanying this report. 
CHAPTER VII. 
SUMMARY OF LOCUST FLIGHTS FROM 1877 TO 1879. 
PLIGHTS IN 1877. 
We have prepared the accompanying maps (Nos. 2-4) in order to give 
at a glance a succinct view of the leading facts regarding the distribu- 
tion of the hatching-grounds and course taken by the resulting swarms 
in 1877, 1878, and 1870, respectively. These maps may be compared 
with those for 1874 and 1870 in the First Annual Report of the Com- 
mission. 
The majority of the facts regarding the flights in 1877 are taken from; 
the First Annual Report. By looking at Map No. 2 (1877) it will be- 
seen that the large majority of the hatching-grounds were those made- 
by the locusts which invaded the Temporary Region, lying in general 
east of the 104th meridian, in 187G. It will be remembered that the 
young of these locusts hatched in the spring of 1877, and. while most of 
them were killed by the cold and late rains, many winged their way 
towards the Northwest, some dropping down and alighting by the way T 
while a comparatively few reached the permanent breeding-grounds on 
the Rocky Mountain Plateau, whence their progenitors of the year pre- 
vious departed for the regions lying to the southwest. 
A few scattered arrows without barbs will, however, be seen in Texas, 
Indian Territory, Western Arkansas, Southeastern Kansas, Southeast- 
ern Nebraska, Southeastern Dakota, Western Iowa, and Southwestern 
Minnesota. These indicate the scattered flights which, late in the sea- 
