120 ASSOCIATION OF ORGANISMS THE WEB OF LIFE 



called " cattle-pens." Some remarks will be made in a subsequent 

 chapter on ants as slave-owners, and on the beetles, &c., which live 

 in their nests. 



The caste-system is carried to an extreme in one of the 

 common Foraging -Ants (Eciton hamata, see vol. ii, p. 104) of 

 Tropical America, a carnivorous species which possesses a power- 

 ful sting. Besides winged males and wingless females there are 

 " soldiers " with enormous jaws, large workers, and two sizes of 

 small worker. These ants and those of allied species have no 

 permanent abode, but wander about from place to place after the 

 fashion of armies. After carrying on offensive operations for 

 some time they construct temporary quarters, where they cultivate 

 the domestic virtues and bring up their offspring. Belt gives the 

 following account of ants of the sort in regard to this matter (in 

 A Naturalist in Nicaragua}'. "They make their temporary 

 habitations in hollow trees and sometimes underneath large fallen 

 trunks that offer suitable hollows. A nest that I came across in 

 the latter situation was open at one side. The ants were clus- 

 tered together in a dense mass, like a great swarm of bees, 

 hanging from the roof, but reaching to the ground below. Their 

 innumerable long legs looked like brown threads binding together 

 the mass, which must have been at least a cubic yard in bulk, 

 and contained hundreds of thousands of individuals, although 

 many columns were outside, some bringing in the pupae of ants, 

 others the legs and dissected bodies of various insects. I was 

 surprised to see in this living nest tubular passages leading down 

 to the centre of the mass, kept open, just as if it had been formed 

 of inorganic materials. Down these holes the ants who were 

 bringing in booty passed with their prey. I thrust a long stick 

 down to the centre of the cluster, and brought out clinging to it 

 many ants holding larvae and pupae." Ants as agriculturalists and 

 mushroom-growers have been dealt with in an earlier section (see 

 vol. i, p. 207). 



SOCIAL NET- WINGED INSECTS (NEUROPTERA). The interesting 

 social insects known as Termites live in complex communities 

 somewhat resembling those of Ants, with which, under the name 

 of " White Ants ", these forms are often confounded. The resem- 

 blance, however, is very superficial, while the differences are pro- 

 found. Termites are not invested in strong plate-armour, their 

 exo-skeleton being comparatively thin, nor do they possess poison- 



