October, ’18] 
FLINT: CHINCH-BUG ENEMIES 
419 
day per square yard, or about two million per day for a forty acre 
field; this estimate being based on the results of the above insectary 
feeding experiments where only chinch-bugs were offered as food. 
In the above counts it should be kept in mind that certainly not 
over one-half and probably not over one-third of the Blechrus present 
were counted. This insect is very active and seeks to hide on the 
least disturbance and its small size renders it very hard to see. 
The same is also true of Pagasa fusca. While in this case the insect is 
somewhat larger it is even more easily alarmed. Even the numbers of 
predators shown in the above counts however would easily account 
for ten chinch-bugs per square yard per day. 
Fifteen bunches of grass in a moderately infested cornfield were 
carefully examined and yielded four hundred fifty-four chinch-bugs, 
two ladybugs, three Reduviolus, five predatory flower bugs and five 
Chrysopa larvae, or enough predatory species to account for at least 
twenty chinch-bugs per day. 
During the entire month of August, 1915, examinations made in 
cornfields in west central Illinois showed the predatory flower bug 
often averaging five to six per stalk of corn and Chrysopa larvae, 
nymphs and adults of Reduviolus , Pagasa fusca and adults of Blechrus 
abundant in all chinch-bug infested fields. 
It seems probable from the abundance of these insects in the fields 
and the numbers of chinch-bugs known to be eaten by them that when 
after a period of abundance the chinch-bug increase is checked by 
adverse weather conditions, that these predatory species together with 
the egg parasite may keep them from causing damage for a number of 
years. During the season of 1917 with a wide area in Illinois danger¬ 
ously infested with chinch-bugs no marked damage has been done 
partly because of the abundance of these predatory species in the fields. 
Reduviolus and Pagasa fusca have been unusually abundant in chinch- 
bug infested fields during the past summer. 
