300 



ZOOLOGY 



group or caste known as soldiers, with enormous heads. 

 These peculiar individuals, which occur especially in 



History of 

 the ant 

 colony 



From Brehm's " Thierleben " 



FIG. 108. Ants. 1-8, Formica rufa: i, male; 2 a and b, workers, much enlarged ; 

 3, female; 4, head of worker ; 5, larva; 6, pupa cases; 7-8, pupa. 9-11, Campono- 

 tus herculeanus : Q, worker; 10, male; n, female. 



the genus Pheidole, found commonly under stones, have 

 brains no larger than those of their small-headed 

 fellows. In some cases the differences between ants 

 are due to special causes such as the presence of para- 

 sites, and do not come under the head of normal 

 polymorphism. 



3. The history of an ordinary ant colony is roughly 

 as follows : At a certain time of year, differing with 

 the locality and species, the functional sexes are pro- 

 duced. These are nearly always winged, and have the 

 instinct to leave the nest, rising into the air for the 

 marriage flight. During this period they are attacked 

 by various enemies, but those which survive return to 

 the earth, not to leave it again. The males die, but the 

 females seek a place to found a nest, or sometimes 



