INJURIES CAUSED BY ANTS. 131 



Means of preventing the Ants from ascending the Trees. When they have 

 begun to attack a tree it is with extreme difficulty that they can be per- 

 manently driven off. Pyrethrum dusted over those upon the tree, and 

 scattered over the ground about its base, kills all the ants with which 

 it comes in contact, and affords temporary relief, but its effect is not 

 lasting, and it does not always prevent their return. Coating the raw 

 spots witl? shellac and protecting the trunk with a band of tar and other 

 viscid substances cannot be permanently relied upon to keep them off. 



Sir John Lubbock, in his work on Ants, Bees, and Wasps, speaks of 

 isolating nests of ants " by fur, with the hair pointing downwards," 

 but we are not told what kind of fur was used. A broad band of fur 

 tied around the trunk of the tree, and with the hair pointing downwards, 

 is effectual in preventing their ascent. The skin of the rabbit has been 

 used with success, but probably that of any fur-bearing animal would 

 answer. 



Fur does not form a barrier absolutely impassable to ants, and they 

 will frequently clamber through a very narrow band, but they expe- 

 rience great difficulty in making their way against the hairs, and almost 

 invariably become confused and turn back, if the distance exceeds 1 or 

 2 inches. 



Still more simple and almost as effective is a barrier of chalk. This 

 is applied by rubbing a lump of dry chalk over the bark to form a band 

 at least 8 inches wide, and completely encircling the trunk. In at- 

 tempting to cross such a band the ants nearly always slip and fall to 

 the ground. The fine interstices of the bark are filled with loose grains 

 of chalk, in which their claws find a very treacherous support. While 

 fresh and dry the chalk band is well nigh impassable to ants of the size 

 and weight of the Solenopsis, but dews at night, or rains, and the moist- 

 ure of the atmosphere in a short time change the character of the sur- 

 face by causing the grains of chalk to cohere with sufficient firmness to 

 support the weight of the insect and they then cross it in safety. The 

 device cannot, therefore, be regarded as a permanent one and requires 

 frequent renewal, but it may be resorted to temporarily when a piece of 

 fur is not at hand. 



Very soft, fine clay, fuller's-earth, or talc may be substituted forchalk^ 

 but in all cases must be applied by rnbbing on from a dry lump. Good 

 results cannot be obtained by using any of these substances in powder, 

 dry, or as a whitewash applied with a brush. 



