130 ZOOLOGY. 



the Red Wood Ant, F. rufa) inflict a -wound with 

 their strong mandibles, and then, bending the abdomen 

 forwards under the thorax, squirt the contents of the 

 poison-bladder into the wound. Ants form colonies, 

 always of large size, and consisting of reproductive 

 and sterile individuals. Their food is both of animal 

 and vegetable nature, but chiefly consists of insects 

 and similar small animals. They mostly devour 

 caterpillars, but also dead or wounded beetles {e.g. 

 cockchafers), mammals, birds, and reptiles. As de- 

 stroyers of caterpillars they are of use, but this is 

 true more of those living in woods than those which 

 inhabit fields and meadows. Ants are fond of all 

 sweet substances ; when they enter houses the sugar 

 jar is very often the end they have in view. They 

 are particularly fond of licking up the sweet juice 

 which aphides excrete from their abdomens. On 

 plants infested with aphides many ants are found 

 which greedily sip up all the drops hanging from the 

 abdomens of the aphides ; they may even promote the 

 shedding of the juice by stroking the abdomens of the 

 little animals with their antennae. There are, indeed, 

 species of ants which carry the aphides to the plant 

 parts on which they thrive best, and again, when these 

 are sucked dry, transport them to other uninjured 

 parts. Sometimes aphides are kept in the overground 

 or underground nests of the ants. The common 

 yellow meadow ants shelter aphides in their sub- 

 terranean nests, where they live on the roots of 

 grasses and other plants. In order to get, when 

 necessary, fresh food for these "milch kine," they 

 occasionally enlarge the nest, so that new plant roots 

 are laid bare, and they then carry the aphides to 

 these. 



During the greater part of the year only workers, 

 larvse, and pupse are found in an ants' nest, but 

 reproductive individuals appear in summer, disap- 

 pearing again before the cold weather comes on. As 



