A Monograph of the Formicidae of South Africa. 387 



ventrally flattened teeth. Nodes of petiole stout, the 1st node usually 

 cuboid or somewhat conoid, the dorsal lace sometimes tectiform, the 

 ventral surface produced into a laminate process ; 2nd node globose, 

 the ventral surface bearing a blunt tubercle in front. Abdomen 

 oblong, the sides not very convex, the 1st segment forming the whole 

 of the dorsum. Femora and tibiae thick. 



9- Antennae 11-jointed. Abdomen visually more elongate and 

 less convex laterally than in the $ . Wings with 1 cubital cell and a 

 closed radial cell. Otherwise like the ^ . 



(J. Antennae 11-jointed. Eyes larger than in the 9 > ocelli small. 

 Epinotum generally bidentate. Nodes longer than in the 9 • Scrobes 

 present as in the $ and 9 • 



I have not drawn up a key to the few species which I have seen, as 

 the majority of our species are unknown to me in nature. Moreover, 

 a perusal of the literature concerning this genus plainly indicates th;it 

 many of the so-called species and races are very closely allied, so much 

 so that I believe a study based on more abundant material will later 

 on serve to reduce the present number of species to a much smaller 

 figure. A marked general uniformity in colour, sculpture, and main 

 structural features exists in all our species. They are all black, with 

 the scapes, tarsi, and tibiae more or less reddish. In all, the sculpture 

 of the head consists of a coarse reticulation ; sometimes the rugae are 

 sharp, in other cases flattened or abraded, and are also frequently 

 emphasised in the longitudinal direction. The thorax, at least 

 anteriorly, is more coarsely reticulate than the head. The nodes are 

 very strongly rugose, and the abdomen has a fundamental sculpture 

 of very regular and small reticulations. This fundamental sculpture 

 also occurs on the head and thorax in the spaces between the larger 

 reticulations, but is usually less distinct than on the abdomen. The 

 length of the epinotal spines compared with the length of the interval 

 between their bases is of some diagnostic value, but their degree of 

 divergence is less reliable, being subject to an appreciable degree of 

 variation even in examples taken from the same nest. The denticulations 

 of the margins of the thorax, and their number, are also somewhat 

 variable. The length of the abdomen and the degree of convexity of 

 its sides are perfectly useless characters, since a wide range of 

 variation exists in the various specimens from one nest, and it is 

 thcrofore most regrettable that species have been erected partly on 

 such characters. 



All the species of this genus are tree-ants, usually forming medium- 

 sized nests in hollow twigs and stems, or more rarely, under the bark. 



