180 HYMENOPTERA. 



workers the ocelli are often wanting, though present in the 

 winged individuals of both sexes. The anteunaa are long, 

 slender and elbowed. The mandibles are stout, and toothed, 

 though in those species that do not themselves labor, but en- 

 slave the workers of other species, they are unarmed and 

 slender. The maxillary palpi are from one to six-jointed, and 

 the labial palpi two to four-jointed. The fore-wings usually 

 have but a single complete subcostal (cubital) cell. The sting 

 is often present, showing that in this respect as well as their 

 ^fossorial habits the ants are truly aculeate Hymenoptera. The 

 larva is short, cylindrical, with the end of the body obtuse. 

 The rings of the body are moderately convex. The head is 

 rather small and bent upon the breast. The larvae are fed by 

 the workers with food elaborated in their stomachs. 



The larvae of the stingless genera usually spin a delicate 

 silken cocoon, while those of the aculeate genera do not. Both 

 Latreille and Westwood, however, state that sometimes, as in 

 Formica fusca, of Europe, the pupae are naked, and at other 

 times enclosed in a cocoon. 



The colonies of the different species vary greatly in size. In 

 the nests of Formica sanguinea the number of individuals is very 

 great. The history of a formicarium, or ant's nest is as follows : 

 The workers only (but sometimes the winged ants) hibernate, 

 and are found early in spring, taking care of the eggs and 

 larvae produced by the autumnal brood of females. In the 

 course of the summer the adult forms are developed, swarming 

 on a hot sultry day. The little yellow ants, abundant in paths 

 and about houses in New England, generally swarm on the af- 

 ternoon of some hot day in the first week of September, when 

 the air is filled towards sunset with myriads of them. The 

 females, after their marriage flight in the air, may then be seen 

 entering the ground to lay their eggs for new colonies, or, as 

 Westwood states, they are often seized by the workers and 

 retained in the old colonies. Having no more use for their 

 wings they pluck them off, and may be seen running about 

 wingless. According to Gould, an early English observer, 

 the eggs destined to hatch the future females, males and 

 workers, are deposited at three different periods. 



The nests of some species of Formica are six feet in diameter 



