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JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 11 
and second instar chinch-bugs; both nymphs and adults have been 
seen a number of times in the field feeding on the early stages of the 
chinch-bug. In cornfields it would sometimes be found to average 
five and six to the stalk of corn over the entire field. 
The insectary experiments with this species showed that about 
twelve first instar chinch-bugs were required for the flower bug to 
complete its growth to adult, and that these were taken at the rate of 
a little less than one per day. Their appetite for chinch-bugs did not 
decrease when the adult stage was reached as they still continued to 
feed at about the same rate as the nymphs. 
Only two of the ground beetles common in the chinch-bug infested 
field could be induced to feed upon chinch-bugs in the course of the 
insectary experiments. Casnonia pennsylvanica has been seen feeding 
upon chinch-bugs in the stubble fields but only in one or two cases 
during the past five years. The results of the insectary experiments 
do not show that this beetle would be of much importance in reducing 
the number of chinch-bugs in an infested field. One specimen ate 
ten chinch-bugs in forty-eight days, another eight during the same 
period, while a third only ate five in forty-two days. Only chinch- 
bugs in the later stage of growth were eaten. 
The small striped ground beetle, Agonoderus pallipes, is very common 
in all grain fields in the central and southern part of Illinois but was 
never seen to attack living chinch-bugs in the field. In the insectary 
experiments with this species one beetle under observation for fifty- 
five days ate seven dead chinch-bugs but would not attack living bugs 
although confined with them for this entire period. Another specimen 
of the same insect kept under the same conditions for eighteen days 
ate one dead chinch-bug and one cast molt skin. 
In the field larvse of Coccinellids were frequently seen to feed upon 
chinch-bugs. Several attempts in the insectary to get the number of 
chinch-bugs eaten by the different species of these larvae were without 
definite results. The Coccinellids were never contented in any of the 
several types of cages used and spent nearly the entire time trying to 
get out, all dying within a week. A few chinch-bugs were eaten by 
them however. 
Experiments with a few other species of ground beetles found in the 
chinch-bug infested fields did not show that these insects fed upon 
chinch-bugs. 
To try and get a definite idea of the abundance of the chinch-bug 
predators in the fields counts were made of the number of these insects 
occurring in a measured square yard of stubble in a number of fields 
in central Illinois during July. On the average enough predaceous 
insects of the above species were found to eat eleven chinch-bugs per 
