31 
fully exposed to the sun, speedily killed them. The coal-tar barrier 
was, in fact, required but once, and the kerosene emulsion was used 
only to destroy the bugs which had entered the field before the 
experiment began and a few which escaped into it in an interval be- 
tween a shower of rain and the establishment of the tar line. As the 
protected field of corn bore a good crop while other fields in the 
neighborhood were almost wholly destroyed, the demonstration of 
the usefulness of this method was complete for these extreme con- 
ditions. 
Experiments of IQ04. — Wishing to know, however, what might 
be done by similar operations. under more ordinary circumstances, 
■especially when a chinch-bug outbreak was but just beginning and 
when the weather was generally unfavorable to success, I prepared 
in the spring of 1904 for several field trials, to be made at different 
places in southern Illinois where a previous inspection had shown 
that the chinch-bugs were present in numbers sufficient to threaten 
more or less injury to wheat and corn. The fields selected were in 
four localities: near Carbondale, in Jackson county; near Dubois, 
in Washington county ; and near Fairman and Odin respectively, in 
Marion county. 
The experiment was placed in charge of Mr. E. P. Taylor, and 
I owe the results here reported to his energy and faithfulness in the 
field, and to the fulness and exactness of his notes. 
Although the prospect of insect injury was considerable at all 
these places in the early part of the year, the weather of the spring 
and early summer was so wet and much of the time so cool that the 
multiplication of the insects was in great measure prevented, and 
they finally became abundant enough to injure corn seriously only in 
the Carbondale neighborhood. The whole experiment was faith- 
fully carried through, however, at all the above places, and with use- 
ful results at each. 
At Carbondale, rain fell twelve times and on eleven different days 
between June 24 and July 25, and the ground was kept so moist 
by rains at all the places mentioned that the dusty furrow could not 
be long maintained at any of them. As a consequence, the tar line, 
with post-hole traps, was used throughout, and kerosene emulsion 
was only occasionally applied, as found necessary. 
The tar lines laid at these various places aggregated more 
than a mile and a half in length (508 rods, exactly), and were main- 
tained for periods varying from eleven to twenty-eight days, the 
total of this procedure being equivalent to the maintenance of an 
effective coal-tar barrier a mile in length for twenty-seven days. 
Post-holes were dug from one to two feet deep at a usual distance of 
