6 UNITED STATES ENTOMOLOGICAL COMMISSION. 



A ditch 3 feet wide, unless correspondingly deep, will be more apt 

 to permit the escape of the insects when once in than a narrower one. 

 In hopping, the more perpendicular the direction the insects must take 

 the shorter will be the distance reached. Of course, the wider the 

 ditch, if it be correspondingly deep,, the more effectual will it prove. In 

 exceptional cases, when the locusts are nearly full grown and the wind 

 is high, so as to assist them, even the two-feet ditch loses much of its 

 value. 



Next to ditching, the use of nets or seines, or converging strips of 

 calico or auy other material, made after the plan of a quail-net, has 

 proved most satisfactory. By digging a pit, or boring a post-auger hole 

 3 or 4 feet deep, and then staking the two wings so that they con- 

 verge toward it, large numbers of the locusts may be driven into the 

 pit after the dew is off the ground. By changing the position of this 

 trap, much good can be done when the insects are yet small and huddled 

 in schools. But all modes of bagging, netting, crushing with the spade 

 or other flat implements, and burning, which can be employed to good 

 advantage when the insects first begin to hatch, become comparatively 

 useless when they begin to travel in concert over wide stretches of land. 

 The same may be said of all the mechanical contrivances to facilitate 

 the destruction of the insects ; they are useful if used in concert in a 

 given neighborhood soon after the young hatch, but subsequently do 

 not compare to ditching. There are a number of contrivances that have 

 been more or less successfully used, but we cannot treat of all of them 

 in detail. We shall, rather, at this time, content ourselves with descrip- 

 tions of a few, which will illustrate the principle to be kept in view. 



Those used in Minnesota, so far as we can learn, are applications of 

 one principle, viz, an open-mouthed bag, dragged by hand or horse j>ower. 

 We have seen a very large one that would take from eight to twelve 

 bushels of pupae per day ; but this was after the insects had been pretty 

 effectually fought by burning and otherwise. It was very effective. Its 

 owner proposes to place his whole dependence on it next year. It had 

 one addition over others that we think valuable. It ran back 10 feet 

 or more to a bag, and near the rear end two or three square feet of cloth 

 had been cut out and replaced by wire gauze. This gave a chance for 

 the air to draw through, and as locusts worked toward the rear end 

 they made way toward the light shining through the wire. This machine 

 was rigged on cart-wheels, and the only expense was in getting three 

 long poles from the woods, and in purchasing about forty yards of cot- 

 ton muslin. 



Maj. J. G. Thompson, of Garden City, Minn., has used with satisfac- 

 tion a net made as follows : 



Two pieces of common batten about 16 feet long were used as frame-work for the 

 mouth of the net, one for the bottom and one for the top. From the end of the bottom 

 piece a wooden shoe of the same material ran back about 6 feet to steady the trap and 

 serve as a runner. To the rear end of this shoe a similar piece was fastened by a hinge, 

 and ran forward and was fastened to the top piece of the frame, so that the mouth of 

 the trap would open and shut like a jaw. To hold the mouth open, two short upright 

 posts were fastened to the top piece by a hinge, and rested upright upon the bed-piece. 

 The net itself was made of cotton cloth for the bottom, and the top was made of mos- 

 quito-netting. The mouth of the net extended 16 feet from one side of the trap to the 

 other, and the net ran back about 6 feet to a point with a hole at the end to let out the 

 insects collected. A boy ten years old can draw one end of this net, and by the use of 

 it Major Thompson saved one piece of wheat. 



Similar machines have been drawn by horses hitched to each side of 

 the trap, being 12 to 16 feet apart. The horses serve the purpose of 

 driving the locusts inward toward the mouth of the.net. There have 



