116 Annals of the South African Museum. 



Key to the $ $ of the Sub- Genus Dorylus. 



(4). 1. Scape about as long as the first 6 or 7 joints of the flagellum, and shorter 



than half the flagellum. 

 (3). 2. Mesonotum wider (5 mm.) ; lateral margins of the stipites, seen from above, 



sinuate, narrowed at about the middle helvolus, Linn. 



(2). 3. Mesonotum narrower (4 mm.) ; lateral margins of the stipites not sinuate, 



but forming an even convexity from base to apex . . . . affinis, Shuckard. 

 (1). 4. Scape shorter than the first 5 joints of the flagellum ; mandibles decidedly 



small brevipennis, Emery. 



S unknown furcatus, Gerst. 



3 unknown braunsi, Emery.. 



D. helvolus, Linn. (Plate IV., figs. 33, 33a, 336, 34, 34a). 



Mus. Ludov. Ulrich., p. 412, $ 1764. Syst. Nat. ed. 12, vol. 1, 

 968 (Mutilla) £ , 1767. Emery, Bull. Soc. Ent. Ital., vol. 19, 

 p. 350, 8 ? $ , 1887. Trimen, Proc. Ent. Soc, London, p. 24,. 

 ?, 1880. 



2f. or $ maxima. 8 mm. Castaneous, mandibles and anterior 

 portion of head and apical segments of abdomen, darker. Legs 

 very scantily pubescent, flagellum moderately pubescent, a few 

 long hairs on the petiole and abdominal segments. Whole body, 

 except the posterior face of the node and the flagellum, very shining, 

 evenly and distinctly punctured. The punctures are larger and 

 deeper on the head and thorax, shallower and smaller on the petiole 

 and abdomen. The petiole is reticulate-punctate on its posterior 

 face ; from each puncture arises a pale, microscopic hair. 



Head at least one-quarter longer than it is wide, parallel-sided, 

 posterior angles rounded but very prominent, owing to the deep and 

 almost angular occipital emargination. Mandibles scarcely longer 

 than half the width of the head, very blunt at the apex, and with 

 a blunt tooth near the middle of the internal margin. Clypeus 

 almost linear, except in the middle, where it is slightly and triangu- 

 larly extended between the frontal carinae, and produced into a. 

 small platform on the anterior margin. The frontal carinae short 

 and narrow, free and raised at the sides into a lobe which ends pos- 

 teriorly in a sharp spine. Scape of antenna incrassate and flattened 

 towards the apex, about two-thirds as long as the flagellum ; the 

 latter 10-jointed, all the joints except the last wider than long. 

 The scape and flagellum together are about three-quarters the 

 length of the head. 



Pronotum rounded in front, narrower behind than in front. Pro- 

 mesonotal suture well defined ; meso- and epinotum rather flattened 



