June, ’20] 
PARKER: CHINCH BUG IN MONTANA 
321 
In June, 1911, the writer found that nearly every clump of bunch grass 
upon the open prairie harbored from one to twelve adults and during 
the first week in May unbroken sod land in the vicinity was said to 
have swarmed with nymphs. 
Forms Found 
Both long and short winged forms were found in about equal 
numbers. 
Distribution 
The area so heavily infested by the chinch bug in 1911 lies south of 
Glasgow between the Milk River and the Missouri River and covers at 
least four square miles. During the same year an area of five or six 
square miles lying north of the Milk River in the vicinity of Glasgow 
was examined in many places, but not a chinch bug could be found. 
At Hinsdale, 30 miles west of Glasgow, several chinch bugs were found 
in the first two wheat fields examined, but no more could be found 
anywhere during a five hour search. It therefore seems probable 
that while the most severe infestation in 1911 was in the district south 
of Glasgow, the insects also occurred scatteringly over a much larger 
territory. It has not been abundant at Glasgow since 1911. 
On July 2, 1915, an adult chinch bug was taken by H. L. Seamans 
at Brady, which is 240 miles west of Glasgow and only about 40 miles 
from the continental divide. The elevation at Glasgow is 2,087 feet 
and at Brady 3,800 feet. 
Source of Infestation 
The finding of the chinch bug in Montana is not surprising, for it 
has long been threatening the southern and eastern borders of the 
state. In 1905, Webster 1 mapped it as occurring over all the eastern, 
southern and central states, and as far north as Manitoba. The 
western boundary of the infested area passed through central Colorado, 
out into the southeastern corner of Wyoming, passed diagonally across 
western South Dakota and cut North Dakota almost in half. It is 
probable that from this infested area the chinch bug has slowly worked 
its way up the valley of the Missouri River. 
Mr. E. D. Ball: Have you had these chinch bugs examined by 
specialists? 
Mr. J. R. Parker: They were examined by Mr. Van Duzee. 
Mr. E. D. Ball: I collected a species of chinch bug in the northern 
part of the state of Colorado, beyond the present range of the chinch 
bug and they were determined by Professor Montandon, the world’s 
specialist on chinch bugs, as a different species from that in the south. 
bureau of Entomology Bulletin, 69, page 11. 
