Practical Considerations. 



161 



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 lo- 

 cust, especially in the pupa state, can hop more than two 

 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 

 bave 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 and QEdipodae tumble into such a 

 ditch, and seldom get out again. I would remark in this 

 connection, also, that a ditch three feet wide, unless cor- 

 respondingly deep, will be more apt to permit the insects 

 to escape, 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. 



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. 



4. Catching. — There are innumerable mechanical con- 

 trivances for this purpose. The cheapest and most 

 satisfactory are those intended to bag the insects. A 

 frame two feet high and of varying length, according as it 

 is to be drawn by men or horses, with a bag of sheeting 

 tapering behind and ending in a small bag or tube, say one 

 foot in diameter and two or three feet long, with a fine 

 wire door at the end to admit the light and permit the 

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