404 Annals of the South African Museum. 



(4). 3. Head not very strongly striate, and with the transverse anastomoses 

 almost obsolete ; thorax coarsely and longitudinally rugoso-striate, 

 transverse rugae few, not clearly reticulate . . Marleyi. Forel. 



(3). 4. Head longitudinally striate, also reticulate ; thorax clearly reticulate- 

 rugose. 



(6). 5. Inner pair of teeth on occipital angles usually smaller than the outer 

 pair ; spaces between the reticulations on the head shallow. 



Baumi, Forel, race batonga, Forel. 



(5). 6. Inner pair of teeth on occipital angles usually as large, or almost as 

 large as the outer pair ; the spaces between the reticulations on the 

 head fairly deep . . . batonga var. bulawayensis, Forel. 



(2). 7. Base of abdomen deeply sulcate-striate. 



(9). 8. Basal half of abdomen sulcate-striate, the striae continued to the 

 apex, but becoming rather feeble over the middle 



micans, Mayr, race durbanensis, Forel. 



(8). 9. Basal fourth only of the abdomen sulcate-striate, the striae altogether 



absent from the middle two-fourths, the apical fourth feebly striate ; 



intrudens, Smith, var. intermedAus, Sant. 



(1). 10. Head almost quadrate, or only feebly narrowed in front of the eyes 



brevisetosus, Forel, race Luja.e, Forel. 



Tribe PHEIDOLIM, Emery. 



This tribe includes the two genera Messor and Pheidole. The 

 former has polymorphic ^ ? > the different forms varying mainly in 

 size, the structure being but little modified. On the other hand, in 

 Pheidole the £ £ are strongly dimorphic and consist of large-headed 

 % % and ordinarily shaped £ $ , the two not being connected by 

 forms intermediate in size or structure except in the small sub- 

 genus Allopheidole, in which intergrading forms occur. Ayfliaenoqaster , 

 Mayr, Goniomma, Forel, Messor, Forel, and Ischnomyrmex, Mayr, 

 have been reduced to the rank of sub-genera of Stenamma, Westwood, 

 by Prof. Emery. They are undoubtedly all closely related, but since 

 they continue to be treated by recent authors as distinct genera, 

 Messor is retained as a distinct genus in the following pages. 



Genus MESSOR, Forrel. 



Ann. Soc. Ent. Belg., vol. 34, C.E., p. lxx, 1890. 



Aphaenogaster pars Mayr, Atta, Latreille, etc. 



Characters. 



^ . Polymorphic. The ^ $ differ chiefly in size, very little in 

 structure. For convenience one may divide the £ $ into major, 

 minor and media, but there are no sharply defined categories in this 



