A Monograph of the Formicidae of South Africa. 5 



Another important point which the reader should particularly 

 note is that if we regard the epinotum as the basal segment of the 

 abdomen, the thoracic and abdominal regions are contiguous at 

 their bases, i.e. the metanotum on one side and the epinotum on 

 the other. Hence the bases and apices of the separate segments of 

 those two regions lie in opposite directions; it should therefore be 

 distinctly remembered that when the base of the epinotum is referred 

 to, that portion of it is indicated which adjoins the meso-metanotal 

 part of the thorax. In the worker caste the metanotum is usually 



\ 





\ 





6rrV \ 





\ \ 



c fl 



am. i( | ^ 



/ ff 



fc - -f— "T i f 





b 



4--A 



\ ° 



-J - — o 



0772. 





Fig. 4. 





Head of Euponera sennaarensis. 



vim = masticatory or terminal margin 



of mandible. 

 bm = basal margin of mandible. 

 em = external margin of mandible. 

 c = clypeus (dotted). 

 fc = frontal carina. 

 fs = frontal sulcus. 

 E = (compound) Eye. 

 o = ocellus. 

 cm = occipital margin of the head. 



Fig. 5. 



Head of Opthalmopone Berthoudi. 

 Showing fa = frontal area. 



small, and so completely fused with the mesonotum as not to be 

 recognizable, so that the dorsal suture which separates the metanotal 

 region from that of the epinotal is commonly called the meso- 

 epinotal suture, although strictly speaking it should be called the 

 meta-epinotal. In the male and female the metanotum is distinctly 

 defined (see Figs. 1 and 2, pp. 3, 4). The epinotum is so closely 

 attached to the thorax, in the worker, that its boundaries are not 

 always easily distinguishable. For purposes of description it will 

 be convenient to treat of it as composed of three parts, viz. the 

 sides, the dorsum, and the declivity (see Fig. 3, p. 4). The 

 declivity is the sloping part of the epinotum, adjoining at its apex 

 the base of the petiole. The dorsum, when flat or concave, is 



