beyond the posterior margin by about one-fourth of its length in the minor, and by about one-seventh in the major. Close to the base it has a transversely-placed projection or tooth...; the scape is widely curved beyond the level of the projection. Flagellum without a distinct club, all the joints subequal in length, the first about three times longer than wide. Pro-mesonotum evenly arched. The long and slender mesonotum is almost cylindrically narrowed. Epinotum almost cuboid, the dorsum horizontal, nearly twice as long as wide, the declivity almost vertical; between them are two broad flat teeth, or two sharp and nearly dentiform angles, the space between the angles excavated. First node wedge-shaped, with a broad peduncle in front, as high as thick at the base, emarginate above, and with a longitudinal impression behind. Second node also narrowed above. Legs very long, thin and slender. Head, pronotum and petiole feebly shining, in the minor closely, finely and rather irregularly reticulate, in the major fairly coarsely striate in addition; mesonotum and epinotum (including the declivity) coarsely and transversely rugose or striate, the sides longitudinally striate below. Abdomen shining, shallowly and finely coriaceous. Pilosity sparse, reddish and short.

Legs and antennae with decumbent, or sometimes oblique, long hairs. A fringe of long red hairs on the anterior margin of the clypeus and some not very long ammochaetae under the head. More or less dark brown or brownish-black; mandible and tarsi yellowish to reddish, flagellum and legs brownish-yellow to reddish-brown.

"Q. 10-3-13 mm. Thorax almost as wide as the head. Disc of mesonotum smooth, with sparse, piligerous punctures; the rest of the thorax coarsely and unevenly rugose. The epinotum with very feeble and broad tubercles. Wings fairly long, almost vitreous (slightly tinged with yellow), costa and nervures brown. Otherwise just like the major but often with a more brightly coloured head. The tooth on the scape of the antenna a little smaller. Legs often quite red.

66

“♂. 8.5 mm.

The tooth on the scape very distinct. Mandibles with 7 or 8 teeth. Head longer than wide, with a a very distinctly, feebly convex hind margin. Second joint of the flagellum longer than the first. The epinotum forms a complete oblique plane, hardly convex. Head reticulate-punctate, almost dull. Thorax irregularly and fairly coarsely rugose, shining. Otherwise like the

minor. Black; legs, base of the mandibles, antennae, apical margins of the abdominal segments and the pilosity brown; apical half of the mandibles reddish.

"A harvesting ant (Aristida grass, Augea capensis, etc.).

"Luderitzbucht, Kammagas and Steinkopf, Little Namaland (Schultze); Steckstown, Cape Prov. (Wartmann)."

Also at Kimberley, and Ababis, S.W. African Protectorate (R. W. Tucker). These agree with Forel's description in every way except the colour, which is darker, almost pitch-black, the tarsi and the apex of the flagellum dark reddish-brown. From an examination of these specimens and of a co-type ( media) in my possession, it appears to me that the emphasis laid on the presence of a tooth on the scape is somewhat misleading. Unless seen at a certain angle from above, this dentiform projection at the base of the scape is by no means conspicuous, and moreover, a similar though smaller tooth occurs in capensis and its var. pseudoaegyptiaca. Denticornis differs from the latter species chiefly in its much more shining integument, in its feebler and more superficial sculpture of the head, and by its narrower form.

Var. PARVIDENS, Forel.

Loc. cit., P. 15. .

. Differs from the type by the much smaller tooth on the scape. Some specimens have also more obliquely exserted hairs on the tibiae.

"Kubub, Great Namaland; under stones (Schultze)."

66

Var. BRUNNI, Forel.

Ann. Soc. Ent. Belg., vol. 54, p. 444, ☀, 1910.

Q. 6-8.5 mm. Allied to var. parvidens but smaller, of a light brownish-red, with the tarsi, antennae and mandibles yellowish-red or reddish-yellow. The sculpture of the head is finer and closer, and the occiput is transversely striate (longitudinally so and more rugose in the type of the species and var. parvidens).

"S. W. Africa (Brunn); Steckstown, Cape Prov. (Wartmann)."

M. BRAUNSI, Forel.

Ann. Soc. Ent. Belg., vol. 57, p. 138, 9, 1913.

. 5.5-8.3 mm. Head and abdomen yellowish-brown, paler in the media and minor. Thorax and petiole brownish-yellow in the major, dirty ochreous in the smaller. Legs and antennae ochreous, mandibles light brownish-red, the masticatory margin dark brown. Pilosity coarse, erect and reddish; a very fine pubescence

only on the legs and antennae. Head and thorax moderately, the abdomen very shining. Head finely longitudinally striate, the striae almost obsolete on the occiput. Thorax and nodes feebly reticulate, the pronotum also feebly striato-rugulose transversely. Epinotum strongly and transversely striate. Abdomen and legs smooth. In the smaller the sculpture is almost entirely effaced except on the epinotum.

Very similar to denticornis, Forel, with which it should perhaps be placed as a race. It differs from that species as follows: It is smaller and more robust. The thorax is shorter and the pro-mesonotum more convex; the epinotum is also more convex, rounded and without teeth, not angular between the two faces. The nodes of the petiole are more convex above and not so high; the 2nd node is as long as wide (slightly wider than long in denticornis in the major). The scape is toothed at the base, but the tooth is less acute. Willowmore, Cape Prov. (Dr. Brauns). (S.A.M., R.M., G.A. colls.)

GENUS PHEIDOLE, Westwood.

Ann. Mag. Nat. Hist., vol. 6, p. 87, 1841.

Characters.

4. Antennae 12-jointed, usually very short in proportion to the length of the head; club 3-jointed, fairly distinct. Head extremely large, disproportionately so compared with the rest of the body. The back of the head usually deeply emarginate, so as to divide that region into two lobes; a median occipito-frontal sulcus usually well defined. Clypeus short, especially at the sides, the median portion produced backwards between the frontal carinae. The frontal area generally depressed. The frontal carinae short, raised at the sides so as to furnish a slight depression in front to accommodate the base of the scape. Mandibles broad, triangular, indistinctly dentate. Pro- and mesonotum much raised above the level of the epinotum and forming a hump. The pronotum is usually more or less angularly produced at the sides, or even bituberculate. Mesonotum frequently with a transverse impression, behind which lies a more or less distinct scutellar region. This is sometimes margined above by a transverse torus or hump. Behind the scutellum a fairly welldefined portion of the metanotum is often present (in the majority of ants not visible in the ). Epinotum armed with two spines or teeth. First node of petiole wedge-shaped or conical, the peduncle in front very short. Second node with the sides produced into angles

or spines, seen from above, more or less lenticular or lozenge-shaped. Abdomen oval, the 1st segment larger than the remaining segments taken together.

Q. Antennae 12-jointed, usually very long, rarely shorter than the head and thorax together. Head of normal proportions, the occiput not emarginate, but generally convex. Thorax longer than in the ; the pro-mesonotum not gibbous as in the 2, but nevertheless retaining (on a much reduced scale) the general features exhibited in that caste; the scutellum hardly defined, the metanotum not at all. Epinotum bispinose or bidentate. First node of petiole with a fairly long peduncle, the node much thicker above than in the ; the 2nd node globose or campaniform, rarely transverse. Abdomen relatively longer than in the .

FIG. 20.-Head and thorax of P. excellens, race rhodesiana. 4.

9. Antennae 12-jointed. Head not wider, or very little wider than the thorax, not emarginate posteriorly, but rather convex or only feebly concave. Pronotum without tubercles or prominent angles, not exposed above. Mesonotum usually flat above in its posterior half. Dorsum of epinotum short and declivous; the spines or teeth generally broader and relatively much shorter than in the and 4. Petiole very similar to that of the 4. Abdomen elongate-ovate, not very convex above, with more or less pronounced basal angles. Wings fairly long, with two closed cubital cells.

. Antennae 13-jointed, the scape very short, rarely more than half as long as the long diameter of the eyes, flagellum filiform, the 1st joint globose. Head much wider in front than behind. Mandibles small, usually dentate. Eyes and ocelli large. Median area of clypeus convex. Frontal carinae very short, ill defined. Thorax similar to that of the 9, but the mesonotum is more convex

and projects further forwards in front. Dorsum of epinotum generally very short, the teeth obsolete and indicated only by obtuse tubercles. First joint of petiole barely or not at all pedunculate, the node flattened, the posterior face usually dorsal in position. Second node more or less hemispherical, sometimes laterally dentate as in the Wings as in the .

This genus occurs in both hemispheres and includes a very large number of species, many of which break up into numerous varieties and races. All the South African species with which I am acquainted are omnivorous, with a marked fondness for sugary substances, but some species, e. g. excellens, crassinoda and Arnoldi, are mainly graminivorous, harvesting the seeds of grass in the same way as the species of Messor. They do not appear, however, to limit themselves. so exclusively to the seeds of one particular kind of grass as in that genus, nor are their stores of seeds so large. Nearly all the species which I have seen usually nest in the ground, and the nest entrances are generally clearly indicated by irregular craters of earth around. them. A few species may sometimes be found nesting in hollow trunks of trees, but such a situation is uncommon. The duties of the large-headed soldiers appear to be mainly to remove to and from the nest any matter which is too bulky to be handled by the ☀☀, and with their powerful mandibles to dismember the bodies of their insect prey. For purposes of defence they appear to be of very little use, being far less courageous than the small worker. This is easily seen on digging up a nest, when it will be found that the workers attack the intruder, stinging and biting to the best of their ability, while the soldiers immediately seek shelter among the debris, or in the deeper parts of the nest. Nevertheless, if they are sufficiently irritated, they will also attack, and bite so firmly to the skin of the hand that they will allow themselves to be torn in half rather than loosen their hold.

The species of this genus are pre-eminent in their readiness to harbour other insects in their nests. In Rhodesia it is in the nests of P. punctulata that one may most frequently find such myrmecophiles, especially Paussidae, Clavigeridae and Pselaphidae. Amongst the and of the genus, there is a general uniformity of structure which renders the determination of the different species a difficult matter, so that it is essential that examples of the caste should be obtained, in which a greater specific diversity is apparent.

In the treatment of this genus I have endeavoured to arrange the species into groups, such grouping being based chiefly on the