48 Annals of the South African Museum. 



which are carried off by means of carefully arranged raids in which 

 the ants march in double file. This is the species which is popularly 

 called the " Matabele " ant, and like its cousin Paltothyreus, it is 

 also endowed with a very offensive odour. They stridulate very 

 loudly when disturbed, and their sting is exceedingly painful. The 

 entrance to the nest consists of one or more simple holes, without 

 any mounds of earth around them.* (S.A.M., R.M., G.A., coll.) 



* Since the above descriptions were written, I have had the good fortune to 

 witness the singular spectacle of a migration of this species, and to obtain thereby 

 a specimen of the real queen of this ant. As I intend to give a fuller account 

 elsewhere of the manner in which the migration was carried out, it will suffice 

 here to remark that the old and new nests were situated about 60 feet apart, and that 

 the journey was accomplished by the colony in stages, in the following manner. 

 At about 15 feet from the old nest the first camp was formed and a halt made, 

 until all the eggs, larvae, and pupae were collected together, and until most of the 

 stragglers had come in. Similar halting-places or temporary camps were formed 

 every 15 feet or so. I saw the queen in the first camp, but failed to seize her with 

 my forceps ; the same thing occurred when she was seen once again in the second 

 camp, and it was only in the third camp that I managed to capture her, not an easy 

 task when the viciousness of the g $ is taken into account. 



In the Introduction to this work (p. 6) I pointed out that if Emery's suggestion 

 be correct that the larger worker-like form is the ergatoid ? , the species would be 

 peculiar in having normally more queens than workers in the nest. The discovery 

 of the true, although ergatoid, queen, disposes of this anomaly, and at the same 

 time indicates the remarkable fact that the workers of this Ponerine ant are 

 dimorphic. I append herewith a description of the queen, from which it will 

 be seen that although similar in general appearance to the 5 major, it differs 

 from it radically in important particulars, notably in the shape of the epinotum 

 and petiole. 



? . 18'5 mm. ; length of abdomen, 9 mm. (in the $ major, 4-5-5 mm.) ; width 

 of abdomen, 4 mm. (in the g major, 2-3 mm.). The pubescence is a little more 

 abundant and longer than in the $ major, but the pilosity of the body is much 

 more abundant, especially on the sides of the pronotum, the mandibles and the 

 margins of the abdominal segments. The fine sculpturation is similar to that 

 of the g major, but the mandibles are more coarsely punctured, and the head, 

 thorax, petiole, and abdomen have some scattered, shallow, and fairly large 

 punctures, from which arise" the pilose hairs, almost entirely wanting in the 

 5 major. 



The head, pro- and mesonotum as in the 5 major, but the meso-epinotal suture 

 is much deeper and wider. The dorsum of the epinotum is not longer than the 

 pronotum (much longer in the 5 major). Seen from the side, it is not horizontal 

 as in that caste, but convex longitudinally from the base to the apex, and convex 

 from side to side, not sub-margined as in the 5 5 . A longitudinal and very 

 distinct median groove runs from the base almost to the brow of the declivity ; 

 this groove is but faintly indicated in the 5 major. The declivity is similar to 

 that of the 5 major, but not so steep, and the lateral tubercles above are flatter or 

 less dentiform. The node of the petiole is not sub-cubic as in the 5 ? , but almost 

 squamiform and slanting forwardly, so that the anterior and posterior faces are 

 not vertical or almost so, as in the 5 5 , but obliquely sloping. The anterior face is 

 strongly concave, and the posterior face is only a little less so. Seen from the side, 



