A Monograph of the Formicidae of South Africa. 417 



structure of the 1/ 1/ . Although I believe that the arrangemeut 

 adopted is a fairly natural one for our South African species, yet 

 it is not claimed that it definitely indicates a natural or close 

 relationship amongst the components of each group. 



(N.B. — In measurements of the length of the head the mandibles 

 are excluded. Contrary to the method adopted in the case of 

 Strtimigenys, etc., it is more convenient in dealing with this genus 

 to include the occipital lobes in the measurement ; the latter is,. 

 therefore, taken from the level of the anterior margin of the clypeus 

 to the level of the apices of the occipital lobes. The width of the 

 2nd nodes of the petiole is measured across its widest part, i. e. 

 including the lateral teeth or spines. The length of the 1st segment 

 of the petiole should be taken along the ventral surface of the 

 segment.) 



(A) PtTNCTTJLATA Group. 



1/ . Head very convex above and at the sides, and (neglecting the 

 mandibles and occipital emargination) , more or less round in outline. 

 Occipital sulcus rarely deep. The posterior half or less of the head 

 smooth and shining. Second node of the petiole not sharply spinose 

 at the sides. 



(2) 1. Mandibles strongly and fairly closely punctate- striate Foreli, Mayr. 

 (1) 2. Mandibles finely and sparsely punctured. 



(8) 3. Posterior half of the head shining and without sculpture. 



(5) 4. Occipital emargination of the head shallow, its apex not angular; 



sides of the head behind the eyes moderately convex 



punctulata, Mayr. 

 (4) 5. Occipital emargination much deeper ; the sides behind the eyes very 



convex. 

 (7) 6. Occipital emargination angular at its apex ; a distinct trace of the 



anterior ocellus is present in a pit-like depression rotundata, Forel. 



(6) 7. Occipital emargination arcuate at its apex ; no trace of the anterior 



ocellus present .... rotundata var. Ilgii, Forel. 



(3) 8. Less than half of the head posteriorly shining and without sculpture. 



(10) 9. Only the posterior fourth of the head smooth and shining, occipital 



emargination wide and very shallow ; second node angulated at the 

 sides ...... victoris, Forel. 



(9) 10. Posterior two-fifths of head smooth and shining ; occipital emargina- 



tion narrow and fairly deep ; sides of second node convex. 

 (12) 11. Length 4 - 5 mm. ; mandibles shallowly punctured ; dorsal edge of first 

 node emarginate ..... tenuinodis, Mayr. 



(11) 12. Length 5 - 3 mm.; mandibles deeply punctured; dorsal edge of first 



node entire . . . tenuinodis var. sipapomae, Arnold. 



