No. 5- ] Methofls ailopted in Tiijiis for clesfroyiug Locvsts. 129 



Trap B, which is identical in size, is simpler and equally effective. 



It consists merely of two laths of wood for 



the sides and two others for the ends. These 



laths are about 15 centims. wide and entirely lined with zinc on one side, 



but only partially on the other. 



When the trap is prepared, the frames are placed along the edjres 

 with the tin lining undermost and protruding- about one- third over the 

 brint. The four corners where the frames join should be carefully closed, 

 and all apertures filled in with earth. 



The locusts entering these traps are able to crawl up the earthen 

 sides, but on reaehiiig the protruding rim of zinc, they lose their grasp 

 and fall back into tlie pit, 



A great advantage in this invention is the portability of the laths 



and the simplicity of their adjustment to the 

 Advantages of Ti'np B. 



trenches. 



1 he traps can also be easily enlarged either in length or breadth by 

 adding the necessary laths. In fact, daring the latter part of the cam- 

 paign it has been found that large traps, measuring 12 metres to 16 

 metres in length, by a metre in width and depth, are preferable to the 

 smaller ones, when the locusts are numerous and their movements rapid. 



I am indebted to Major R. Catroux, Controleur Civil of the Tunis 

 district, for the following rules to be observed in the employn)ent of the 

 newly invented traps. 



During the first fifteen days traps of two metres long by one metre 

 Eules for employment of wide are placed at distances of about 50 metres 

 traps. apart along the line of screens. 



From the fifteenth day to the thirtieth day the length of the traps 

 are increased in proportion to the importance of the columns. They 

 should measure from six metres to eight metres in length by one metre 

 in width and 60 centims. in depth, and be placed about 50 metres apart. 



After the thirtieth day the locusts become exceedingly shy and have 

 been known to halt at a distance of about 400 yards from the screens 

 and to alter their course with such accelerated speed that they have suc- 

 ceeded in outflanking the screens. 



In such eventualities their movements can be successfully intercepted 

 by placing a line or lines of screens projecting at right angles. 



The dimensions of the traps may vary from 10 metres to 20 metres 

 in length, by 1 metre or 2 metres in width, and 60 centims. in depth, 

 situated at distances of 100 metres to 150 metres apart. 



