A Monograph of the Formicidae of South Africa. 195 



males are exceedingly common at lights during the greater part of the 

 year. I have frequently dug up the nests of the variety Arnoldi, 

 without ever having found a $ of any sort, nor have 5 $ of any 

 species been described up to now. I believe that the genus will 

 eventually be found to have only ergatoid queens, or that the egg- 

 laying function (with the production of <$ <$ and ^ ^ ) is possessed 

 by the whole ^ caste. 



y 



Key to the ^ ^ of Ocymyrmex. 



(Note. — In using this key, the term " node of the 1st joint " should 

 be understood to refer to the swollen part of the joint only ; it does 

 not include the narrow and short portion which lies between the node 

 proper and the base of the 2nd joint.) 



(2). 1. Outline of 1st abdominal segment, seen from above, evenly convex 

 from the base, not sub-pedunculate. (Plate V, fig. 53.) 



harbiger, Emery. 



(1). 2. Outline of 1st abdominal segment, seen from above, shallowly concave 

 just beyond the base, more or less sub-pedunculate. (Plate V, fig. 52a.) 



(8). 3. Less than 8'5 mm. long. 



(5). 4. Node of 1st joint of petiole wider than long. Weitzaeckeri, Emery. 



(4). 5. Node of 1st joint of petiole longer than wide, or as long as wide. 



(7). 6. Stouter insect, 2nd joint of petiole hardly longer than the node of the 

 1st joint ; median excision of the clypeus shallow, hardly bidentate ; 

 abdomen red, moderately shining . . var. Foreli, Arnold. 



(6). 7. Insect more slender, 2nd joint of petiole one-third to one-half longer 

 than the node of the 1st joint ; median excision of clypeus deeper, 

 making the margin distinctly bidentate ; abdomen piceous, shining. 



var. Arnoldi, Forel. 



(3). 8. 10-11 mm. long ..... Picardi, Forel. 



The races hirsutus and Wroughtoni, and the var. micans of Weit- 

 zaeckeri are not known to me in nature, and have therefore been 

 omitted from the above key. The different forms of Weitzaeckeri are 

 clearly exceedingly closely allied, and ought not to be considered as 

 ranking higher than varieties. The striation of the head varies in 

 strength and direction, even in specimens from the same nest, so that 

 very little reliance can be placed on that feature in the separation of 

 the species and varieties. 



0. Weitzaeckeki, Emery. (Plate V, fig. 54) 

 Ann. Mus. Civ. Genoa, vol. 32, p. 116, $ , 1892. 

 5. 65-7 mm. Castaneous red, tibiae and tarsi paler, femora and 

 abdomen piceous. In some specimens the colouring is darker, the 



