HYMENOPTERA 363 



six feet across, and sometimes they are much larger than this. New- 

 colonies are often formed by fission, a portion of the colony emigrating 

 and founding a new colony with one or more queens. In this way many 

 colonies are often established in a limited area. The head and thorax of 

 this ant are rust-red, while the legs and abdomen are blackish-brown. 



The blood-red slave-maker, Formica sanguined. — More than a cen- 

 tury ago Pierre Huber called attention to the fact that this species which 

 is common in both Europe and America, keeps in its nests the workers of 

 other species of Formica, which aid in performing the labors of the col- 

 ony. The relations of the two species thus associated have been com- 

 monly regarded as that of slaveholders and slaves. The slaveholders 

 obtain their slaves by making periodical forays on the colonies of the 

 common black Formica fusca, and of other species of Formica, and bring- 

 ing to their own nest the worker larvae and pupae. Some of these are 

 eaten, but others are reared, and these knowing no other home take their 

 place as active members of the colony. 



In the blood-red slave-maker the gaster is black or brown and there 

 is a notch in the margin of the clypeus. The nests of this species are 

 low obscure mounds of earth or are excavated under stones or logs or 

 around stumps. Many subspecies and varieties of this species are recog- 

 nized, some of which do not keep slaves. 



The shining amazon, Polyergus liicidus. — The species of the genus 

 Polyergus were named amazons on account of their warring habits. 

 Species of this genus occur in this country as well as in Europe. The 

 shining amazon is a beautiful, brilliant red species widely distributed in 

 the Eastern and Middle states. The species of this genus are slave- 

 makers that have become absolutely dependent on their slaves. They 

 cannot build their own nests or feed themselves or care for their young, 

 but have only retained the power of fighting to get more slaves. Their 

 mandibles are sickle-shaped and fitted only as weapons of offence. These 

 ants also make periodical forays on the colonies of other species of 

 Formica and carry home the worker larvae and pupae. The workers 

 developed from these perform all of the labors of the colon}' - except that 

 they take no parts in the forays on the colonies of other ants. The young 

 queens of Polyergus, being unable to work, establish new colonies of their 

 species by securing adoption in some small weak colony of another 

 species of Formica after killing its queen by piercing her head. 



The corn-field ant, Lasius niger americanus. — To the genus Lasius 

 belong several common species of small brow T n ants that make small 

 mounds in various situations. These ants are fond of honey-dew and 

 not only care for the aphids from which they obtain it but collect the 

 eggs of the aphids and store them in their nests through the winter, and 

 in the spring place the recently hatched plant-lice on the stems and roots 

 of the plants on which they feed. A well-known species of this genus is 

 the corn-field ant which cares for the corn-root aphid and places it on the 

 roots of corn in the spring. 



The honey-ants, Myrmecocystus. — The ants of this genus are found 

 in the arid regions of the Southwest, from the city of Mexico to Southern 

 California and to Denver, Colorado. They have received the name of 

 honey-ants from the remarkable fact that with them some of the workers 

 function as honey-pots or reservoirs for storing the honey-dew collected 

 by other workers, from nectar excreting galls on trees and from aphids 



