A Monograph of the Formicidae of South Africa. 543 



It is generally assumed on the evidence of the structure of the 9 

 (although I believe no proof has yet been furnished) that the queens 

 of this sub-genus and of the sub-genus Atopogyne exhibit a method of 

 nest-formation, based on a temporary social parasitism on other 

 species of Gremastog aster, similar to that shown in the case of the 

 dolichoderine Bothriomyrmex mericlionalis, var. atlantis. In this 

 species the queen enters the nest of a Tapinoma erralicum and takes 

 refuge from the attacks of the Tapinoma workers by climbing to the 

 back of their queen. While in this position she applies her energies 

 to the task of sawing off the head of the unfortunate victim below 

 her, and by the time this has been accomplished has acquired the 

 nest odour of the Tapinoma and is then adopted by the workers in 

 place of their dead and mutilated queen. The workers bring up the 

 progeny of the Bothriomyrmex queen, and as the former eventually 

 die of old age the nest becomes a pure colony of Bothriomyrmex* In 

 one species of Oxygyne, CL Ranavalonae, the aged queen has the 

 abdomen enormously enlarged, like the queens of the permanently 

 parasitic genus Anergates. 



C. (sub-gen. Oxygyne) Oscaris, Forel. 



Sclmltze, Eeise Siid- Africa, vol. 4, p. 7, £ , ?, < J, 1910. 



" ^ . 3 - 5-4 mm. Mandibles 4-dentate, narrow, closely striate, 

 punctured, nitidulous and pilose. Clypeus widely impressed in the 

 middle in front and shallowly emarginate. Frontal carinae very short, 

 almost obsolete. Frontal area indistinct. Eyes moderately flat, 

 placed somewhat behind the middle of the sides. Head wider than 

 long, feebly concave behind, the sides very convex. The scape extends 

 beyond the back of the head by a good third of its length ; club 3- 

 jointed with distinct constrictions between the 3 joints; 2nd- 

 7th joints of the flagellum only a little, but nevertheless distinctly 

 longer than wide. Pronotum rounded, feebly impressed in the 

 middle. Mesonotum without a median carina, barely convex, with 

 an arcuate transverse torus at about the posterior third (the convexity 

 of the torus in front) ; behind the torus a transverse impression. 

 Thoracic constriction fairly strong. Dorsum of epinotum convex, 

 wider than long, with a very shallow longitudinal groove, the 

 epinotal spines very acute, nearly as long as the dorsum or as the 

 interval between them, distinctly curved a little inwards and down- 

 wards. Declivity concave, shorter than the dorsum. First segment 

 of the petiole a little longer than wide, trapezoidal, with laterally trun- 



* See Santtschi, ' Ann. Soc. Ent. France,' vol. 75, pp. 302-92, 1906. 



