COISTTEOL OF ARGENTINE ANT IN CALIFOENIA. 



19 



success attending this method in the Southeast induced the writers 

 to conduct an experiment under the more arid conditions in the South- 

 west. 



A 10-acre orange grove at Upland, Cahf.,.very severely infested 

 with Argentine ants, was selected for the experiment. Five-gallon 

 tin coal-oil cans (9J by 9^ by 13^ inches) were used for traps (see 

 fig. 8), being much cheaper than the wooden boxes, and affording 

 complete protection from rain or winds. One end was cut along three 



Fig. S.— Winter trap nest, coiiaistui;^ of 5-gallon oil cans filled with 

 nesting material, in place at base of tree. 



sides and this acted as a flap over the entrance of the can, protecting 

 it from beating rains. Tliree hundred and fifty cans were used, being 

 divided into seven lots of 50, each lot containing a different filler. 

 These were respectively green grass and dirt, green grass, green alfalfa, 

 dry straw, wet straw, moist dirt, dirt, and leaf mulch. The cans were 

 placed on a side, close up to the base of the tree. Approximately 3 of 

 the 10 acres were reserved as a check, the remaining 7 being covered 

 with ant traps, one to each tree on about 3 acres and one to every 

 other tree on the remainder. These were placed December 1, 1917. 



