A Monograph of the Formicidae of South Africa. 405 



caste, a complete gradation existing between the largest at one end 

 of the scale and the smallest at the other. The smaller the worker 

 the smaller becomes the head in relation to the thorax, and the dorsal 

 profile of the thorax tends to a more even and continuous convexity. 



$ major. Antennae 12-jointed, flagellum filiform and without a 

 distinct club. Clypeus nearly flat, the median area produced back 

 between the frontal carinae and hardly raised at all. Frontal carinae 

 short, the free edge usually more or less raised. Eyes rather small. 

 Mandibles triangular and massive, more or less dentate. Thoracic 

 sutures distinct. Thorax narrower than the head ; pronotum much 

 larger than the mesonotum ; constricted and deeply depressed at the 

 meso-epinotal suture. Epinotum bidentate or unarmed. First seg- 

 ment of petiole conical, pedunculate in front ; 2nd segment trans- 

 versely globose. Abdomen oval, the 1st segment as long as the rest 

 taken together. 



§ . Similar to the ^ major, but the head is smaller and the eyes 

 slightly larger ; ocelli small. The thorax is massive, much higher 

 than the head, almost as high in the middle as it is long. Pronotum 

 vertical, not exposed above. Anterior wing with two closed cubital cells. 



$. Antennae 13-jointed ; the scape half as long as the head. 

 Mandibles small, distinctly dentate. Clypeus narrow. Eyes not 

 very large and the ocelli much smaller than usual in this sex. Thorax 

 as in the ? . Nodes of petiole shorter and flatter. Abdomen sub- 

 globose, pointed and narrower at the apex. 



The members of this genus differ from the closely allied genus 

 Aphaenogaster in their diet. The latter, when not entirely carnivorous, 

 have a mixed diet, whereas the species of Messor are graminivorous 

 and harvesting ants. M. barbarus, as its name rightly indicates, has 

 its headquarters in North Africa, but including its numerous sub- 

 species and varieties has a much more extended range, which comprises 

 all the Mediterranean region. 



In South Africa it is represented by the subspecies capensis and 

 several varieties of the same. 



M. barbakus, Linn., race capensis, Mayr. 



Syst. Nat. Ed. 12 a, vol. ii, p. 962, £ , 1767. 

 Leach, Entom. Archiv., vol. i, p. 4, $ , $ , <$ , 1827. 

 (Race) Verb. Zool. Bot. Ges. Wien, vol. 12, p. 743, £ , 1862. 



„ „ „ „ vol. 16, p. 896, ?, <J,1866. 

 „ Reise d. Novai-a, Zool., vol. ii, Formicid., p. 87, ^ , 1865. 

 " ^ • 6-11 mm. $ major brownish-black, frontal carinae, apex 



