[10] REPORT UNITED STATES ENTOMOLOGICAL COMMISSION. 
before that time high up on their regular course. Such immense masses couhl not de- 
scend each night without literally covering and burying the ground. Docs the main 
army continue its march night and day, only dropping a few stragglers as they become 
too weary or hungry to keep up f 
Question 1 b. August, 1868.— On the 8th, 18th, 19th, and 20th days of flight the ther- 
mometer ranged from 57° to 86°. 
July, 1875.— From the 13th to the 22d the maximum temperature was from 70 to94 3 , 
the minimum from 52° to 66°. 
June 14 and 10, 1870. — (Flight from northeast to north on northerly winds); tem- 
perature 57° to 79°. 
August 24 to 28. — Northeast wind; temperature 59° to 80°. 
August 29. — Wind south; immense numbers; temperature 74° to 86°. 
I do not think they rise to join the crowd above. I never knew them to rise unless 
there were swarms passing over at the time, in cloudy weather. Still, when in regu- 
lar flight, I do not think clouds stop them, although it obscures them from view. As 
the sun has appeared through broken clouds I have often seen them passing, while 
when the sun was obscured they were invisible. 
Question 1 a and v. Invariably in the direction of the wind, be its force more or less. 
Question 1 c. By arranging the focal distance of a spy-glass to fit objects at a known 
horizontal distance, and comparison of appearance and size of locusts, I think the 
passing swarms are generally from one-hall' to one mile high, varying at times, proba- 
bly seeking currents of wind or greater or less velocity. In case of sudden and heavy 
rains, when the air was fidl of them, none of consequence came down with the rain. 
It seems impossible that they could fly through the. storm. Do they rise above it ? In 
heavy swarms my glasses show them as dense as they can move without interference. 
The extent of the swarms it is difficult to ascertain, as the observer can only see a 
small belt. They may extend indefinitely right or left. During the flight from June 
15 to 25, of 1875, I telegraphed east and west, and found a continuous line moving 
northward of 110 miles, anil then somewhat broken 40 miles further. The movement 
of the wind for live days (15th to 20th) averaged about 10 miles per hour; and the lo- 
custs evidently moved considerably faster than the wind, at least 15 miles per hour. 
The swarm I estimated at from one-quarter to one-half mile deep. It seemed like 
piercing the milky-way of the heavens ; my glasses found no limit to them. They 
might have been a mile or more in depth. They were visible from six to seven hours 
each of the successive five days, and I can see no reason to suppose their flight was 
checked during the whole five days. If so, the army in the line of advance would be 
120 hours X 15 miles per hour= 1,800 miles in length, and say at even 110 miles in 
■width an area of 198,000 miles ! and t hen from one-quarter to one-half mile deep. This 
is utterly incredible. Yet how can we put it aside? 
Question 2'. According to all my records and recollections they rise to depart between 
9 a. m. and 12 in., and never unless there is a swarm in motion overhead. 
Question 2a. June 13 to 15, 1868. — Toward northwest on a southeast wind. 
June 20, 1869. — After a four days' southerly wind, they came down largely on a north 
wind. 
June 13 to 22, 1875. — The air was full of them nearly every day, the wind generally 
from south or southeast. The locusts went with it ; two short changes to northeast 
brought them to the ground. 
June 24. — During the forenoon the wind was light from the north and locusts came 
with it (a rare case). At noon a full calm and progress stopped. They circled round 
and round, and many came down. 
June 25 to 28. — Wind southeast. Locusts went on it to northwest. 
July 2, 1*75. — With an east wind flew westward. 
July 7. — Southeast wind, and to the northwest. 
June 14 and 15, 1876. — To the southward on northerly winds. 
August 10. — No wind and no general course. 
August 24 and 25. — Northwest and northeast winds brought a few. On the above 
times the wind was generally light, from 5 to 10 miles per hour ; the weather fair, of 
course, where the locusts were visible, for they are invisible in cloudy weather. 
Question 2b. The temperature at the time of rising has ranged from 70° to 90°. Cold 
or cool weather renders them sluggish. 
Question 2c. The direction always corresponds with the flocks they join, of which I 
have spoken above. I have rarely seen a large number rise at once. The lower air 
will be very full of them, but at least four-fifths of them rise, take long horizontal 
flights, but, seemingly unable to rise, come to the ground again. I presume they have 
to make several efforts before they succeed. •■ 
Question 3. August 24, 1876, I first noticed them. 
Question 7. — A compact earth, as a path or firm, solid, bare ground, with fair expos- 
ure to the sun. It must not be too hard, as the central part of a road or path beat 
very hard. 
Question 8. Warm sunny exposures, not beaten too hard. 
