THE METHOD OF MOVEMENT IN MASSES. 
joined by the rest, and, after miserably laying waste tbeir native fields, they proceeded 
elsewhere in large troops. 
That they will migrate even in small numbers is evident from the 
numerous statements bearing upon this point to be found in the appen- 
dices to our former report. The members of the Commission can all 
bear testimony also to this fact from personal observation. The brood 
of a siugle female will migrate and even cross over the Eocky Mountain 
Eauge without other associates, and during the flying season, on almost 
any clear, warm day, more or less may be seen in the air moving with 
the wiud, sometimes so few and scattering that only here one and there 
one can be seen far up toward the sun by the flash of their silvery 
wings, appearing like floating snow-flakes. 
A much stricter discipline (if such a term can be applied to them) 
appears to prevail in the swarms which come from the permanent 
region than in the local flights within the temporary area. 
"We have assumed throughout our discussion of their flights that they 
move only with the wind when flying in swarms. Although there are 
occasional apparent exceptions to this rule, we think they are only ap- 
parent, and that there are no real exceptions. The facts already given 
show so conclusively that this is the general rule that it is unnecessary 
for us to present further proof now, though we may have something 
more to say when we come to speak of the meteorological influences on 
flights. That no well-attested instance of a swarm flying directly against 
the wind can be shown, we are quite confident ; but that they can and 
do occasionally vary their course from the direction of the wind, beating 
around to the right or left, is certainly true. In addition to the one or 
two instances mentioned in our report, we add the following from 
Bowles, 1 ' 11 who appears to speak from personal observation: 
I have seen a troop of locusts pass through Malaga and enter for a quarter of a 
league ov er the sea ; but when the people began to take pleasure in the hope that 
they would disappear and be drowned, they gave a sweep toward the left, Hew 
straight to the earth, and paused to deposit their eggs. 
The following from our correspondents in reference to the movements 
of the Eocky Mountain locusts, and from authors in reference to the 
swarms of the Old World, will probably illustrate their method of move- 
ment in masses better than any explanation we can give. 
The following letter from Dr. Child, who acted as local observer for 
us at Plattsinouth, Nebr., from which we have already quoted, is so- 
interesting that we give it in full : 
Plattsmouth, Cass County, June 7, 1877. 
1867, July 2. — General south to north direction on gentle breeze (signal office nom- 
enclature of winds) from south. First noticed about 9 a. m.; continued on the 3d in 
a heavy body, as also on the 4th, until 3 p. m., when a heavy rain of 1.60 inches in 1-J 
| hours obscured (?) them. A very few were found on the ground after the storm, but 
not .0001 of what were seen before the clouds obscured them. What became of them 1 
Frequent observations since have shown that when flying with the wind which brings- 
191 Introduz., &c., I. c. 
