TWO DESTRUCTIVE ANTS. 3 



The colonies of this ant are formed by the flight of the females to 

 some point not far distant from the nest. The queen alights, digs 

 beneath the surface, deposits a small quantity of the fungus from 

 the original nest, and on it deposits a number of eggs. 



FORMS. 



This ant occurs in five forms, namely, soldiers, large workers 

 (media), small workers (minima), males, and females. The soldiers 

 are from 10 to 12 mm. in length, with enormously developed heads. 

 The large workers, or media, resemble the soldiers, although the 

 head is somewhat smaller, and the length of the body is between 

 3 and 9 mm. The small worker forms, called minima, are from 1.5 

 to 2.5 mm. in length. The head is still smaller than in the media. 

 Each of these three forms has a special function in the nest. The 

 soldiers are concerned primarily with the protection of the nest. 

 They do not sting, but bite with their mandibles, which are strong 

 enough to draw blood. The large workers and small workers are 

 busied principally with the gathering of leaves for the fungus garden 

 and the preparation of the material on which the fungus grows. 

 The remaining forms are the males and females. These are much 

 larger than the other forms. The female is about 18 mm. in length. 

 The color is dark brown, although the legs are somewhat reddish. 

 The body is covered with dense tawny hair. The wings, which are 

 shed soon after the flight of the queen, are reddish brown, especially 

 along the anterior borders. The males are from 13 to 14 mm. long 

 Avith a head of small size which contrasts greatly with that of the 

 worker forms. The body is densely covered with long yellowish 

 hairs, as is the case with the females. 



REPRESSION. 



The fact that this ant does not coritinue to attack one species of 

 plant continuously, but changes from one to another at frequent 

 intervals, causes it to be of less importance in the destruction of 

 vegetation than it would be otherwise. Nevertheless, the damage 

 to growing crops is frequently heavy, and complaints have become 

 more numerous in recent years on account of the greater abundance 

 of the ants. In many places considerable areas of land are not 

 planted to crops on account of the danger of attack. In all such 

 situations it is necessary to resort to repressive means. 



The best method of control is undoubtedly by means of potassium 

 cyanid.^ Mr. J. D. Mitcliell has conducted the experiments upon 



1 The use of potassium cynnid iu \v:it<'r soUitiou against ants was first followed by 

 Messrs. R. S. Wogluni and Win. Wo'kI. (See Jouruai of Economic Entomology, vol. 1, 

 pp. .'MS-.-MO, 1008.) Mr. II. O. Marsh has also used it. (See Bui. 04, I't. IX, U. S. 

 Dept. Agr., Bur. Ent.. pp. 74-7S, IKlO.j 



