11 
face, 82°, as determined by simply laying the thermometer on the 
ground. 
At 8:30 both air and surface were 74°, observations being taken 
as above. 
At 5 a. m., July 13, the young were more active than the 
adults, and a great many bugs were still collected on lumps of 
earth and in depressions on the surface. A few were crawling and 
falling into the post-holes, about as many having been trapped 
in eight hours and a half during the night as had been caught 
the previous evening in three quarters of an hour. 
At 6 o’clock the temperature of the air was 74°, the thermome¬ 
ter erect and about four feet above the surface. The soil tem¬ 
perature was 78°, thermometer slightly buried. The chinch-bugs 
were now very much more active, and were moving in considerable 
numbers toward the east end of the oval, about six times as many 
(9,000 in round numbers) having collected in the post-hole at 
this point since 5 o’clock as had been entrapped during the entire 
night'. Their activity steadily increased, and in a few moments 
there was a regular procession fourteen feet long moving to the 
eastward along the tar line towards one end of the oval, and to 
the westward for a distance of six feet towards the other, leaving 
an intermediate space of about five feet where there was no ap¬ 
preciable tendency in either direction. Very few bugs passed the 
coal-tar, although it was dry and could easily have been crossed. 
It served practically as an impassable barrier. 
At 9 a. m. the temperature of the air w r as 85°; surface 112 . 
The oval was almost entirely freed from chinch-bugs, the most of 
them having fallen into the post-holes. Two thirds of the entire 
lot that had been placed in this enclosure the previous evening 
were taken from the cans, the great majority having fallen in 
since 6 a. m. If the three thousand chinch-bugs taken from the 
post-holes at 8:30 p. m. the preceding day and those still remain¬ 
ing within the oval are taken into consideration, it is clear that only 
a very small number escaped. 
No. 5. July 13, an experiment similar to No. 4 wms made on 
an oval half as large, with post-hole in one end. Slight rain at 
2 p. m., just enough to settle the dust. Sky cloudy, with light 
breeze from southwest; temperature of air 90°; surface 87°. 
At 2:30 p. m. renewed barrier by pouring coal-tar over line used 
the day before, for a distance of twelve feet on either side, and 
across the ends; but at the east end the tar was poured on the 
ground, as no line had been previously made at this point. One 
gill of chinch-bugs was distributed on the surface of the hard 
ground enclosed. They were very active, and in ten minutes the 
center of the oval w r as comparatively free, the insects forming a 
band next the tar line around the entire enclosure. By 3 p. m. 
the bugs had mostly collected on the south side and in the ends, 
being most abundant in the east end, where they were very active. 
The general movement at this time was to the eastward, but many 
were tumbling into the can at the west end. A strong wind from 
the southwest blew many insects over the line. 
