92 GENERAL ZOOLOGY 



Several species, including the little black ant and the 

 minute red ants, become household pests. 



The honey ant of Texas (Myrmecocys'tus mel'liger) has 

 one set of workers peculiarly modified to act as storage 

 vessels for sweets. The abdomens of these are distended 

 with a store of grape sugar, till they are as large as a cur- 

 rant. These workers cling to the roof of the nest, and in 

 times of famine can be drawn upon for food by the other 

 workers. 



The agricultural ant {Pogonomyr'mex barba'tus) clears 

 large spaces, often several feet in diameter, cutting down 

 all vegetation growing thereon, and rears a grain-bearing 

 grass, storing its seeds in underground chambers. Several 

 kinds of ants have the habit of attacking other kinds and 

 carrying off their pupae. In one (Formi'ca sanguin'ea), a 

 small reddish species, the habit has become firmly fixed, and 

 periodical raids are made upon a larger black species, which 

 are afterwards raised in the nests of their captors. One ant 

 of a slave-making tendency (Polyer'gus rufes'cens), found 

 in Europe, has carried the habit so far that it has lost the 

 power of feeding and taking care of itself, depending entirely 

 on the exertions of its servants. The wars of ants have been 

 known for a long time, and many accounts are extant of the 

 fierceness of the struggle between opposing armies. 



Gallflies and Ichneumon Flies. The gallflies form many 

 of the swellings on plants, known as galls. A common gall- 

 fly of the oak (Amphib' olips) is shown in Fig. 60. The gall 

 is caused by the female laying an egg in the leaf tissue, 

 which swells up when the larva hatches. The young feed 

 on the material of the gall until they are ready to go into 

 the pupal stage. Many of these galls harbor also guest gall- 

 flies, living with the others as commensals. 



Closely allied to the gallflies are the ichneumon flies. One 

 species deposits its eggs in the burrows of a wood-boring 



