42 OUTLINES OF ENTOMOLOGY. 



between the individuals of a colony. The jaws are strong and sharply 

 notched, except in the slave-making species, in which they become 

 almost useless as tools. 



Some species are armed with a sting, and all secrete a peculiar acid, 

 called formic acid, which has very characteristic properties, and pro- 

 duces a slight burning sensation upon the skin. This acid is attractive 

 to certain insects which penetrate to the ants' nests to obtain it from 

 their bodies. It is thought to have medicinal qualities, and in Switzer- 

 land a highly prized vinegar is made from it by boiling the insects in 

 water. It is said that the lumbermen in our northern forests, in the 

 event of a failure of their fruit supply, use these acid insects as a sub- 

 stitute. 



Ants build their formicaries in various ways, according to their 

 species. Some erect conical dwellings above ground from mortar of 

 clay or sand ; others, including a majority of the species, burrow into 

 the earth; while others still inhabit hollow trees or excavate decayed 

 stumps and logs. The nests are marvels of mechanical art, containing 

 store-rooms, nurseries, galleries and other compartments, and are some- 

 times several stories in height, each story being supported upon pillars, 

 arches and cross-beams. 



Not only are these little creatures skillful artisans, but they seem 

 to have quite complex social and governmental systems. When about 

 to make war on a neighboring colony, they sally forth in regular col- 

 umns, and appear to have a corps of officers who take turns in direct- 

 ing the movements. Several species of red and yellow ants capture 

 and enslave various black species. The slaves are obtained by making 

 war on the " negro ants ;" and after the victory which they gain in a 

 majority of the battles, they carry off the pupae of the vanquished 

 colony and rear them in their own nurseries. When the captives are 

 mature, they do not attempt to escape, but seem entirely willing to 

 procure food for their owners and to serve them in any capacity re- 

 quired. 



The larvae of ants are short, white cylindrical grubs, with small 

 heads which are bent forward. These larvae receive the most assiduous 

 care from the workers. They are daily carried about to those parts of 

 the nest where the temperature will best promote their growth. When 

 the weather is pleasant, they are brought in the morning to the upper 

 apartments, that they may receive the benefit of the sun's rays, and at 

 evening they are again removed to the lower chambers where there is 

 less exposure and more warmth. The food with which they are sup- 

 plied must first be chewed and submitted to a process of partial diges- 

 tion by the nurses before it is fed to them, and in all other ways they 

 are the objects of the tenderest interest and attention. 



