June, ’20] 
PARKER: CHINCH BUG IN MONTANA 
319 
of great economic importance hitherto not known to occur in Montana, 
but because its life history differed so strikingly from that reported by 
workers in other states. 
Notes on Seasonal History 
The most surprising feature about the chinch bug in Montana con¬ 
cerns its seasonal history. According to Webster 1 and other workers, 
the chinch bug hibernates only as an adult and even in the more 
southern states, where there are two broods, the majority of the first 
generation do not reach maturity until July. Finding fourth instar 
nymphs as early as May 23, therefore, immediately led us to believe 
that the insects might have hibernated as nymphs rather than as 
adults. The farmer who sent in the chinch bugs stated that he first 
noticed them about April 15, when they appeared to be the same size 
as those sent to the Station on May 23, i. e., fourth instar nymphs. 
Nymphs placed upon oats in the insectary at Bozeman transformed to 
adults on June 12. Pairing was observed in the rearing cage through¬ 
out the month of July and August, but no eggs were seen until August 
20. On September 1 about one-third of the adults were still alive, but 
as yet no young had been seen. On October 5 all the adults were dead, 
but in the cage were a number of dead and a few living chinch bugs in 
the first and second instars. None of these survived the winter. 
On June 26-30 of the same year, the writer visited the Glasgow dis¬ 
trict and found chinch bugs very abundant in prairie grass and in much 
smaller numbers in cultivated crops. The nymphs by this time had all 
transformed to adults, many of which were pairing. 
The same district was visited again on May 13, 1913. It had been 
under water for several weeks, during the spring floods of 1912, which 
may account for the scarcity of chinch bugs that prevailed. Only six 
were found in a day’s search over the territory where they had occurred 
so abundantly in 1911. Four of these were in the fourth instar and 
two were in the third. The season was backward and on that date the 
buds on the cottonwood trees had not unfolded. 
On June 4, 1914, the same vicinity was examined, but a two days’ 
search netted only two chinch bugs, both adults. 
On November 6, 1915, an entire day was spent searching for chinch 
bugs at Glasgow, but not one could be found. During the summer of 
1919 this territory was searched on two different occasions but no 
chinch bugs were discovered. 
Indications of Hibernation of Nymphal Stage 
Kelly and Parks 2 state that in Kansas and Missouri in 1909 the 
1 Bureau of Entomology—Bulletin 69, page 10. 
2 Bureau of Entomology—Bulletin 95, Part III, page 28. 
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