PACKARD.] HABITS OF THE LOCUST. 62^ 



per {Calopfenus apretus) have been kindly sent me by Prof. Samuel 

 Augliey, of the University of ^STebraska : 



1. It is a mistake to suppose that the grasshoppers never fly at night. In August, 

 1866, I was camped on the Bcw Jflver, on an open prairie, in Cedar County, Nebraska. 

 I was lying on a robe outside of the tent, the moon shining brightly. In the evening 

 not .1 grasshopper could be seen or found. At 1 o'clock at nighc the wind shifted from 

 the west to the north, and soon the atmosphere became perceptibly cooler. Suddenly 

 grasshoppers commenced to drop, and continued to fall for nearly half an hour. In the 

 morning the prairie was covered with them. I had a similar experience on two other 

 occasions. On the Verdigris, a tributary of the Niobrara, and on the Upper Elkhorn iu 

 August, 1867. These expericTices are a demonstration to me that they do sometimes, 

 at least, fly on warm moonlight nights. 



2. It appe.nrs doubtful to me whether these migrating grasshoppers ever move faster 

 th.in the wind carries them. In August, 1667, when they were moving over Northern 

 Nebraska, I climhed tall cottonwood trees, and let loose among the flying grasshop- 

 pers bits of cotton. These bunches of cotton moved or were carried forward as fast by 

 the wind as the grasshoppers flew, and in the same direction. In June, 1875, 1 did tho 

 same thing from the cupola of the State University on four different days. When they 

 were flying thickest the bits of cotton would keep even with them as far as they could 

 he seen with a field-glass. And while these few experiments are not conclusive, it ap- 

 pears to me that, until some one sees them move faster than the wind, we have a right to 

 presume that they do not. The only physical exertion, then, that the grasshoppers need 

 to make in order to migrate is to raise themselves into the air and to keep suspended. 

 The winds waft them into (to them) unknown regions. The height to which they 

 often rise is very great. On the 18th of June, 1675, the column that passed over Lin- 

 coln, Nebr., was within 50 feet of being one mile in height. This I ascertained by trig- 

 onometrical determination. 



3. It is probable that their constitutional vigor decays or declines in regions moister 

 than their native habitats. I have attempted to ascertain this by various methods. One 

 experiment was to attach the limbs of mature grasshoppers that were hatched in Ne- 

 braska to a delicate spring-balance, and ascertain in this way the degree of their physi- 

 cal strength. As they varied a great deal in strength, I averaged the strength of tea 

 at a time. The following is an example of such an attempt, the first being taken from 

 Nebraska, and the second from Northern Utah and Wyoming : 



Nebraska. Utah. 



The first grasshopper drew 1. 50 ounces. 1. 75 ounces. 



The second grasshopper drew 1.50 ounces. 2. 00 ounces. 



The third grasshopper drew 1. 25 ounces. 2. 00 ounces. 



The fourth grasshopper drew 1.75 ounces. 1. 75 ounces. 



The fifth grasshopper drew 1. .50 ounces. 1. 75 ounces. 



The sixth grasshopper drew 1. 75 ounces. 1.75 ounces. 



The seventh grasshopper drew 1. 75 ounces. 2. 10 ounces. 



The eighth grasshopper drew 1. .50 ounces. 2.00 ounces. 



The ninth grasshopper drew 2. 00 ounces. 2. 25 ounces. 



The tenth grasshopper drew 1.50 ounces. 1.75 ounces. 



15. 80 ounces. 18. 80 ounces. 



I have ten more tables of the same general character and results. Only in one did 

 the two approach each other. The highest of the Nebraska columns came within half 

 an ounce of the strength of the lowest of one set of ten from Wyoming. These tests 

 were mostly made during July, 1875. I cannot think that the difi"ereiice in strength 

 between the Nebraska and Utah grasshoppers could have been accidental. I reached 

 the same results by the experiment of ascertaining the length of time that the grass- 

 hoppers from the two localities could live without food. Omitting the columns of fig- 

 ures, the average result reached was that the Utah and Wyoming grasshoppers could live 

 three and one-fourth days longer without food than those from Nebraska. Vivisection 

 ))roduced the same results. These and similar experiments satisfied me that away 

 from their natural habirats the constitutional vigor of the grasshoppers becomes im- 

 paired, and that iu a few generations they must tend to run out. 



4. Confirmatory of the preceding conclusion is the following observation : As early 

 as the spring of 1865 I noticed that probably not more than about 50 per cent, of the 

 grasshopper-eggs that were laid the autumn i)reviou8 hatched out. Almost daily from 

 April till far into June I dug over some small portion of the ground where the eggs 

 were thickest. Only an occasional entire, nest of eggs ha.tched out. Some nests would 

 hatch out in part and some not at all. Late in the season many entire nests of eggs 

 conld be found changed into an apparently gelatinous mass. In the spring of 1667 a 

 still larger proportion of eggs seemed to be injured. Segmentation in many eggs had 

 commenced in the fall and during the warm weather of February, and in many nests 



