168 Annals of the South African Museum. 



g. Antennae in the $ and ? with 10 to 12 joints ; clypeus with a trans- 

 verse and high carina on the posterior margin, separating the clypeus 

 from the antennal fossa ; antennae in the $ 10-jointed, 4 joints having 

 been fused into one long joint . . . Tetramoriini, Emery. 



FF. Antennal fossa delimited on the inner side by a carina which passes 

 below the eyes and does not correspond (at least in its posterior portion) 

 to the frontal carina ; antennae 11-jointed in all the sexes. 



Cataulacini, Emery. 



£*. • €Wk Head cordiform, excavated behind and much narrowed in front ; 



antennae in the £ and <j> with from 4 to 12 joints, in the $ with 13 



joints ; radial cell open ..... Dacetini, Forel. 



In the following key, the order in which the genera are placed is no 

 indication of their natural affinities, the latter being treated of under 

 the headings of the tribes. The <$ <$ and ? ? being insufficiently 

 known, no key for the identification of those sexes can be constructed 

 which would be of any practical value. The reader should be re- 

 minded that, as in the case of the three preceding sub-families, the 

 petiole is treated of as a distinct region, in the Myrmicinae composed 

 of 2 joints, and that the abdominal segment which articulates with 

 the 2nd joint of the petiole is referred to as the 1st abdominal 

 segment. The 1st joint of the petiole usually consists of an anterior 

 stalk or peduncle, articulating in front to the epinotum, and bearing 

 behind a sAvollen portion, the node. The 2nd joint (2nd node) is 

 rarely, if ever, pedunculate in front, but it may be more or less 

 narrowed in its posterior half. The structure of the petiole is of 

 considerable diagnostic value, and in order to avoid frequent repetition 

 the following remarks on the shape of the organ should be carefully 

 noted. 



In the ^ , the relative proportions of the node and the peduncle of 

 the 1st joint are very variable. The node may be so large as to 

 render the peduncular portion almost obsolete, as in Meranoplus, 

 Sima, and Cataulacus ; or the node may be of such a shape that no 

 definite line of demarcation can be drawn between a nodal and a 

 peduncular region, Leptothorax, many species of Pheidole. 



The shape of the node is very diverse. It is usually more or less 

 wedge-shaped, or a combination of a wedge and a cone, or it may be 

 more or less cuboid. When the faces of the wedge are approximated 

 and the sides also compressed, it merges into a more or less squamiform 

 node, as in Tetramorium squaminode. On the other hand, when the 

 faces of the wedge are very oblique, we have a tectiform node, as in 

 Cataulacus. Again, if the faces and sides of a wedge are rounded, a 

 more or less conical shape is produced. Such a shape, with the apex 

 very considerably rounded, is one of the commonest, and when much 



