BRITISH ANTS. 



INTRODUCTORY. 



EXTERNAL STRUCTURE. 



ANTS can be distinguished from all the other members of the 

 order Hymenoptera by the construction of the abdomen, which 

 is divided into two very distinct regions, a slender very movable 

 pedicel of one or two joints (the petiole and post-petiole the petiole 

 with a scale or node on the upper surface), and a larger posterior 

 portion, the gaster. 



In certain low forms in the Ponerinae the construction of the 

 abdomen comes nearer to that of some of the Fossores, but such 

 forms, not occurring in Britain, do not concern us here. The con- 

 sistency of the chitinous integument of the body is very variable, 

 being thicker, harder, and more brittle in species of the more 

 primitive groups, Ponerinae and Myrmicinae, and thinner, softer, 

 and more flexible in the more recently developed groups, Dolich- 

 oderinae, Camponotinae, etc. 



Some species are glabrous, and shining ; others pilose and 

 pubescent, opaque, rugose, punctured, striate, etc. 



The hairy covering, when present, consists of (1) pilosity, viz. 

 longer hairs, erect or sub-erect; and (2) pubescence, viz. short 

 closely applied hairs which cover parts, or the whole of the body. 



The Head. 



The head varies considerably in shape, it may be three-cornered, 

 four-cornered, round, oval, elongate, transverse, etc. The organs 

 attached to it are the mandibles and other parts of the mouth, the 

 eyes and the antennae. 



The head above terminates anteriorly with the clypeus, an 

 immovable plate varying in shape. The genae, or cheeks, are situ- 

 ated on either side of the clypeus extending between the eyes and 

 the mandibles. Posterior to the clypeus in nearly all cases is a 



