INTKODL'CTIOX. 



of the various forms assumed by these, with details of the parts 

 of which they are composed. The lettering in all the figures is 

 alike and refers to the same parts. 



Fig. i- 



Fig. i. Head in outline of $ of JEnictus, one of the Dorylin<e. 

 Fig. ii. Heads in outline of A and j of one of the 'Ponerina, B $ of one 

 of the Camponotince. 



a, vertex ; 6, ocelli, generally present in the $ and J , in some 

 cases also in the $ , but more often absent in the last ; o, c, sides 

 of head, which may be straight or convex ; d, frontal area, always 

 small, sometimes well-defined, often obsolete or indistinct ; e, e, 

 frontal or antenna! carinae, rarely nearly obsolete or ill-defined, 

 often very prominent : in many of the Ponerince anteriorly flattened 

 and broad, covering the bases of the antennae ; /, clypeus ; </, g, 

 mandibles, both of which organs vary greatly, not only among 

 the different subfamilies and genera but among the different 

 species of the same genus : generally also they are very dissimilar 



