518 



NATURAL HISTORY OF ARTHROPODS. 



them to extricate themselves, carefully unfolding their legs and smoothing out the 

 wings with truly feminine tenderness and delicacy." 



It has been supposed that the male ants live but a very short time in the adult 

 state ; that the workers exist only a few months ; and that the average life of a queen 

 is not more than twelve months. Lubbock is of the opinion that as a rule the males 

 die almost immediately. At the same time some males of Myrmica ruginoides, which 

 he isolated with their mates in August, 1876, lived until the following spring; one of 

 them till May 17. He found, however, that the life of the queen and workers was 

 much longer than had been supposed. At the time of his writing he had two queens 

 which he had kept seven years, and which still seemed quite strong and well. He had 

 also some workers which had been in his nest six years. 



The three forms of ants may be distinguished as follows : The workers are wingless ; 

 their thorax is narrow, being more or less compressed ; and the ocelli 

 are wanting or are small. They constitute the greater number of the 

 members of the colony, and are the ones most commonly seen. The 

 males and females are always furnished with ocelli, and are both 

 winged when they emerge from the pupa state. After pairing, which 

 takes place in the air, the females shed their wings. Even then this 

 \ sex may be readily distinguished from the wingless workers by the 

 FIG. 649. Eciton large size, by the different form of the thorax (it being wider, not com- 



sumichrastii, . .,..,. 



worker min- pressed, and showing the basal part ot the articulation of the wings), 

 and by the presence of ocelli. The males are intermediate in size be- 

 tween the workers and females. They 

 may be distinguished from the former by 

 the presence of wings and ocelli, and from 

 the females by the fact that the abdomen 

 consists of seven segments in the males 

 and of only six in the females. In a few 

 cases ( Tomognathus and Anergates) the 

 males are wingless. The males, as a 

 rule, are found in the nest during only 

 a small part of the year, but the females 

 are there continually, and frequently several females or queens can be found in the 

 same nest. 



As already stated, the workers are really females in which the reproductive organs 

 are not fully developed. Frequently there are found among the workers of a colony 

 certain individuals which are fertile, but the eggs laid by them always produce males. 

 Hence, the presence of a queen is necessary for the perpetuation of the life of the 

 colony. Lubbock believes that ants, like bees, have the power of developing a given 

 egg into either a queen or a worker. 



The nests of ants vary greatly in form. Many species simply excavate little tun- 

 nels in the earth. These tunnels may open beneath a stone or other object, being thus 

 concealed from view ; or they may have an unobstructed opening in the surface of the 

 ground, surrounded by the small quantity of earth which has been brought up in 

 excavating the tunnel. From these simple nests, made by a dozen workers, every 

 gradation may be found to the large mounds from six to ten feet in diameter, cover- 

 ing a complicated system of tunnels and galleries, and extending many feet under 

 ground, the result of the labors of thousands of workers. In these nests the galleries 



FIG. 650. (Erorfoma mexicana, female. 



