A Monograph of the Formicidae of South Africa. 269 



the declivity is much longer and more oblique, quite as long as the 

 declivity, or a little longer ; the apical angles of the dorsum are also 

 narrower and more dentiform. Otherwise similar. 



Bembesi, Plum tree, and Bulawayo, S. Ehodesia. The nest is 

 smaller and less populous than that of eumenoides. (S.A.M., P.M., 

 G. A. colls.) 



M. Nigra, Mayr. (Plate VII, fig. 91.) 

 Verh. Zool. Bot. Ges. Wien, vol. 12, p. 755, $ , 1862. 

 $ . 5'5 mm. Brownish black ; antennae and legs a little lighter. 

 Pilosity long, yellowish, fairly abundant, erect on the head and thorax, 

 slightly oblique on the abdomen and petiole. Shining. Very strongly, 

 but not densely, longitudinally striate on the head, the striae more or 

 less interrupted in the occipital region. Pronotum also strongly 

 striate transversely ; mesonotum Avith about 8 longitudinal striae ; 

 epinotum with 3 or 4 transverse striae on the raised basal half of the 

 dorsum, and about 5 or 6 longitudinal ones on the posterior half, 

 which do not reach quite as far as the brow of the declivity. Sides of 

 thorax more or less obliquely striate, the striae finer than on the 

 dorsum. Tibiae and scapes smooth, not striate as in eumenoides and 

 striata. The clypeus has one long median stria or cannula, and two 

 or three shorter lateral striae. Mandibles strongly and longitudinally 

 striate, quadridentate. The scape extends beyond the occipital margin 

 by nearly one-third of its length. Head as long as wide, very little 

 narrower in front than behind, the posterior margin shallowly con- 

 cave. Eyes convex, fairly prominent, placed just behind the middle 

 of the sides. Pronotum three times wider than long, the teeth below 

 prominent, triangular, about as long as their basal width. Pro- 

 mesonotal suture obsolete, meso-epinotal not deep, much shallower 

 than in eumenoides. Mesonotum only slightly raised behind, hardly 

 expanded laterally, not auriculate-carinate as in eumenoides. Dorsum 

 of epinotum horizontal, only feebly lobed at the base, almost twice as 

 long as the nearly vertical declivity, twice as long as it is wide at the 

 base. The spines are almost horizontal, slightly divergent, acute, as 

 long as the declivity. Peduncle of 1st joint of petiole thick, hardly as 

 long as the node ; the latter a little longer than wide, flattened above, 

 not conical, the anterior face much shorter than the dorsal surface, 

 and compressed laterally, so as to form a sharp vertical edge ; the 

 posterior face very oblique, about half as long as the dorsal. Second 

 node a little higher than the 1st, subconical, the apex behind the 

 middle, the anterior face oblique and twice as long as the vertical 



