44 
fully 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, 2 feet deep by 2 feet wide, with per- 
pendicular sides. Having been the first to recommend proper ditching 
in this country, I have felt particular interest in its results, and have 
been in no small degree amused at the fault found with my recommenda- 
tion by those who, through slovenly made ditches or other causes, have 
not been successful in this mode of warfare. It is less effectual against 
the newly-hatched young, which more easily crawl up a perpendicular 
bank than the larger ones, and its efficacy will vary with the nature 
of the soil and other circumstances ; for, in proportion as the soil is 
loose, and the ditches hence apt to fill up by the action of strong winds, 
or in proportion as strong winds carry the insects over, ditching will 
necessarily fail. 
Those who, from theory rather than from experience, are skeptical 
about the efficacy of ditching, urge that the locust, especially in the 
pupa state, can hop more than 2 feet. In truth, however, whether 
when traveling in a given direction of their own accord, or when being- 
driven or disturbed, they very seldom leap that distance, as all who 
have had experience well know. That, on a pinch, the pupa can leap 
even farther, is true; but the fact remains that in practice Caloptenus 
spretus seldom does. So the Chinch Bug, though capable of flight, will 
yet tumble into a ditch by myriads rather than use its wings. Even 
the larger winged Acridia andGEdipodae tumble into such a ditch, and 
seldom get out again. I would remark in this connection, also, that a 
ditch 3 feet wide, unless correspondingly deep, will be more apt to per- 
mit the insects to escape, when once in, than a narrower one. In hop- 
ping, the more perpendicular the direction the insects must take, the 
shorter will be the distance reached. 
The efficacy of the ditch depends not so much on the inability of the 
young locusts to jump or scale it, as on their tendency not to do so. In 
the bottom of the ditch they soon become demoralized, crippled, and 
enfeebled by constant effort and the trampling and crowding upon one 
another. 
Protection by Barriers. — Where ditches are not easily made, and where 
lumber is plentiful, a board fence 2 feet high and with 3-inch batten 
nailed to top on side from which the locusts are coming, the edge of it 
smeared with coal tar, will answer as an effectual barrier and prove 
useful to protect fields or gardens. 
A modification of this method was used with great success in 1883 
and subsequent years in the Isle of Cyprus. The "Cypriote system," 
as it has been called, consists of a series of traps and screens. The 
screens are made of light hemp canvas, 50 yards long and 2 feet 6 
inches wide. Near the upper edge of the canvas is sewn a strip of oil- 
cloth 4 inches wide. The screens are fixed to stakes of hard wood firmly 
