48 PAPERS ON THE COTTON BOLL WEEVIL, ETC. 



remains of the weevil larva? destroyed by them, and 1 a dead, moldv 

 weevil larva. 



In the lot of 75 squares kept wet the ants had entered 73, destroying 

 50 stages which probably were larvae and 23 probably pupa?. The 2 

 squares not entered by the ants had contained no stages of the weevil. 

 No signs of parasite destruction could be found in this lot of wet 

 squares. 



A brief summary of the examination of these 150 squares shows 

 that 9 of them did not contain any stage of the weevil. Not one of 

 the uninfested squares nor, apparently, any one of those containing a 

 parasitized or dead larva was opened by the ants. Among the 137 

 squares opened by the ants not a single weevil stage escaped destruc- 

 tion, tho the squares had been on the ground but eighteen hours. 



The unquestionable connection of these ants with the rapid and com- 

 plete destruction of every living weevil stage in 150 squares shows 

 their possible efficacy in the field' under conditions which favor their 

 work. The ants were not exceptionally abundant where the foregoing- 

 demonstration occurred. The nearest nest was under a cotton plant 

 about 3 feet from the bare spot where the squares were exposed. 



On September 25 an examination was made of 300 fallen squares 

 and small bolls collected at random from the ground in this plat. It 

 was found that at that time the ants had destroyed 40 per cent of all 

 weevil stages infesting those squares and bolls. October 6. in an 

 examination of 212 fallen squares and small bolls, it was found that 

 the ants had destroyed 35 per cent of the weevil stages. Observations 

 made after November 1 indicated that the ants had then practically 

 ceased their activity, only about 10 per cent of the weevil stages 

 having been destroyed. The ants appear to be unable to enter the 

 square or small boll until after decay has softened and weakened the 

 resistance of the walls inclosing the weevil. 



DISTRIBUTION. 



These ants nest in the cotton fields and appear to be distributed over 

 most if not all of the cotton belt. Their activity is far greater during 

 hot dry weather than during cold wet weather: and this fact may 

 account in some measure for the effect which wet weather is said to 

 have in greatly increasing the numbers and destructiveness of the 

 insect pests of cotton. 



During the past season Solenopsis geminata var. xyloni has been 

 taken from infested cotton fields in many localities in Texas and west- 

 ern Louisiana. It seems to be perfectly at home in various types of 

 soil, and is undoubtedly of considerable benefit as an established enemy 

 of the weevil in practically all of the area now infested. 



«Bul. 51, Bur. Ent., U. S. Dept. Agric, pp. 137-138. 



