446 Annals of the South African Museum. 



Head, excluding the mandibles, a little longer than wide, wider and 

 higher in front than behind, the sides straight, the posterior emargi- 

 nation deep and angular at its apex, the occipital lobes prominent, 

 narrowed apically. Occipitofrontal sulcus deep in its posterior third, 

 shallow in front. Median area of clypeus rather narrow, strongly 

 carinate in the middle, the anterior margin nearly straight. Frontal 

 area triangular, shining, very slightly depressed. Mandibles smooth 

 and shining, armed with two obtuse teeth at the apex. The scapes 

 extend back to the middle of the head. Pronotum wider than long, 

 the posterior lateral angles fairly prominent but rounded at the 

 apices. Pro-mesonotal suture faintly indicated. Mesonotum sloping 

 steeply downwards in its anterior portion, the scutellar region hori- 

 zontal above and vertical behind, the margin between the two planes 

 transversely concave and slightly produced. Dorsum of epinotum 

 horizontal, about as long as wide, armed with two sharp, slightly 



Fig. 25.— P. Arnoldi, Forel. 



divergent and nearly vertical spines, which are longer than their basal 

 width and as long as the interval between their bases. The declivity 

 of the epinotum is slightly oblique and as long as the dorsum. First 

 segment of the petiole very little longer below than high, the dorsal 

 edge feebly concave, the posterior-dorsal face as long as wide, parallel- 

 sided. Second segment a little more than twice as wide as long, the 

 anterior margin convex, the sides produced into fairly acute teeth 

 curved backwards. Abdomen longer than wide, the sides moderately 

 convex. 



5 . l'8-23 mm. Dark brown, abdomen blackish-brown, legs and 

 antennae dark yellowish-brown, the femora darker, mandibles pale 

 reddish-brown. Pilosity and pubescence sparser than in the %, 

 especially on the abdomen. Head and thorax closely reticulate- 

 punctate and dull ; nodes and base of abdomen finely reticulate and 

 dull, the rest of the abdomen and the legs smooth and shining. Head 

 as wide as long, widest across the eyes, narrower behind than in front, 

 the sides feebly convex, the posterior margin nearly straight. Eyes 

 fairly large, placed in the anterior third of the sides. Frontal carinae 



