378 REPORT UNITED STATES ENTOMOLOGICAL COMMISSION 



A second fact concerning their habits can be utilized. At night, if cool, or at the ap- 

 proach of a shower, they run for shelter ; trees always preferred. If on every acre or 

 every five acres a cistern could be dug and some branches placed high above it or a 

 tree placed as if in the center, immense quantities could be caught. I have seen many 

 bushels massed at the foot of a large elm, between the cavities formed by its great roots ; 

 they were a writhing mass a foot in depth. 



Mr. F. M. Dougan, of Mount Pleasant, Kans., has met with consider- 

 able success with the following mode of ditching : 



Dig a pit 3 feet deep and from 2 to 7 feet wide, then make a ditch 2 or 3 feet broad 

 and about 2 feet deep, running from the pit toward the point from which the locusts 

 are making their appearance. To gather a broad army of insects, take a plow and run 

 furrows diagonally from the ditch, which must afterward have all loose earth removed 

 with spades. In this way the insects are brought together toward the ditch and finally 

 into the pit. 



Ditching and trenching properly come under this head ; and both plans 

 are very effectual in protecting crops against the inroads of traveling 

 schools of the insects. They were found especially advantageous in 

 much of the ravaged country in 1875, where there was little or no hay 

 or straw to burn. They are the best available means when the crops 

 are advanced, and when most of the other destructive methods so advis- 

 able early in the season can no longer be effectually used. Simple 

 ditches, two feet wide and two feet deep, with perpendicular sides, offer 

 effectual barriers to the young insects. They must, however, be kept 

 in order, so that the sides next the fields to be protected are not allowed 

 to wash out or become too hard. They may be kept friable by a brush 

 or rake. 



"The young locusts tumble into such a ditch and accumulate and die 

 at the bottom in large quantities. In a few days the stench becomes 

 great, and necessitates the covering up of the mass. In order to keep 

 the main ditch open, therefore, it is best to dig pits or deeper side 

 ditches at short intervals, in which the locusts will accumulate and 

 may be buried. If a trench is made around a field about hatching- 

 time, but few locusts will get into that field until they acquire wings, 

 and by that time the principal danger is over, and the insects are fast 

 disappearing. If any should hatch within the inclosure, they are easily 

 driven into the ditches dug in different parts of the field. The direction 

 of the apprehended approach of the insects being known from their 

 hatching locality, .ditching one or two sides next to such locality is gen- 

 erally sufficient, and when farmers join they can construct a long ditch 

 which will protect many farms. * * * Where the soil is tenacious 

 and water can be let into the ditches so as to cover the bottom, they may 

 be made shallower and still be effectual. The width and depth of the 

 ditch is important, and as experience differed somewhat, I have been at 

 pains to get the experience of a large number of correspondents ad- 

 dressed by circular. Many have successfully used ditches 2 feet deep 

 and 18 inches wide; a few have made them only 18 inches by 18 inches. 

 Those who have used water found 12 inches by 15 inches sufficient, 

 while the larger number used a ditch such as I have recommended, viz. 



