8 
At 2:10 p. m. we released in this enclosure over a pint of 
chinch-bugs* collected from corn adjacent, and observed their op¬ 
erations in the ditch. Probably one fourth of those collected were 
adults, the remainder being of various ages, mostly pupae or in 
the stage immediately preceding. The adults were much the more 
active, the immature forms tending to accumulate and pile up on 
each other in the ditch. 
The greater part of the chincli-bugs presently deserted the in¬ 
terior of the enclosure and attempted to escape from the ditch, 
forming a continuous belt in the bottom one to three inches wide 
and, where thickest, two or three layers deep. In their efforts to 
escape, the adult bugs persistently climbed up the outer face of 
the furrow again and again, without cessation, falling back each 
time to the bottom as the dust gave way beneath them, the re¬ 
sult being finally to accumulate a slope or talus of dirt at the 
bottom of the furrow of an incline sufficiently gradual to permit 
them to climb it easily. In this manner they slowly advanced 
upward, until in an hour and a half from the beginning of the 
experiment a few escaped at one corner by climbing up a kind of 
ladder way of small clods and roots projecting from the surface. 
Not over fifteen or twenty thus released themselves, when the 
clods were undermined and fell, breaking the passageway. 
An hour and three quarters from the beginning, a post-hole was 
made in the furrow at one end of the enclosure. The chinch- 
bugs nearest it presently fell in, and as others advanced to take 
their places—apparently impelled by the pressure from their 
neighbors—they also were trapped. The impulse was thus grad¬ 
ually passed along the struggling line until within a few minutes 
there was a definite movement of the entire body of chinch-bugs 
for about three feet on each side of the hole towards and into it. 
By 4 o’clock probably half of the chinch-bugs in the enclosure 
had been trapped. This movement had so greatly diminished the 
progress of those attempting to ascend the side of the furrow 
that at this time they had nowhere generally advanced beyond an 
inch below the upper edge. Without the post-hole it is likely 
that they would have begun to make their escape in considerable 
numbers in about two hours from the time the experiment began. 
We collected and brought to the laboratory from the post-hole 
trap and from the furrows about one pint of chinch-bugs, leaving 
the remainder in the enclosure. Next morning the greater part 
of these—probably all except the adults—were dead in the bottom 
of the furrow, killed by exposure to the sun. 
No. 2. July 11, two parallel furrows twenty-five feet long were 
made in a thoroughly pulverized strip of ground in wheat stubble 
by dragging an eight-inch log back and forth through the dirt. 
These furrows were connected at the ends by transverse furrows 
of the same character, thus enclosing a strip of solid, smooth 
*The numbers ot chinch-bugs used in these experiments were determined by counting those in 
a given measure, 10 c. c., a pint being thus ascertained to contain about 132,500, a quart 265,000, and 
a bushel about 8,480,000. 
