A Monograph of the Formicidae of South Africa. 145 



levels. How far the pest has spread in the South African Eegion I 

 am not able io say, but the ant has been recorded as far east as 

 Maseru in Basutoland. 



The sub-family is divided into 4 tribes, of which only one, 



Tapinomini, Emery, is represented in South Africa. 



v 

 Key to the Genera of the Tribe Tapinomini, Emery. 



$ 5 and ? ? . 



(2). 1. Antennae 11-jointed Semonius, For el. 



(1). 2. Antennae 12-jointed. 



(4). 3. Scale of petiole distinct ; base of abdomen not slanting forwards, not over- 

 hanging the petiole Iridomyrmex, Mayr (introduced genus). 



(3). 4. Scale of petiole rudimentary, base of abdomen slanting forwards and over- 

 hanging the petiole more or less. 



(6). 5. Anal orifice apical; abdomen, when seen from above, with 5th segment 

 visible Technomyrmex, Mayr. 



(5). 6. Anal orifice inferior, not apical ; 5th segment of abdomen not visible from 

 above Tapinoma, Foerster. 



(2). 1. Anterior wings with 2 closed cubital cells . . . . Technomyrmex, Mayr. 



(1). 2. Anterior wings with 1 closed cubital cell. 



(4). 3. Scape not longer than the 2nd joint of the flagellum . . Iridomyrmex, Mayr. 



(3). 4. Scape much longer than the 2nd joint of the flagellum. 



(6). 5l. Scape as long as the first 3 or 4 joints of the flagellum taken together ; or if 



longer, then the head is wider than long Tapinoma, Foerster. 



(5). 6. Scape as long as the first 7 or 8 joints of the flagellum taken together ;. 



head not wider than long Semonius, ForeL. 



Genus IEIDOMYEMEX, Mayr. 

 Verh. Zool. Bot. Ges. Wien, vol. 12, p. 702, 1862. 



Characters. 



% . Monomorphic ; petiole with a distinct scale. 



$ . Considerably larger than the £ ; the radial cell of the- 

 anterior wing is closed, 2 closed cubital cells and 1 discoidal cell. 



$ . Scape shorter than the 2nd joint of the flagellum. In our 

 introduced species the mesonotum is very convex and prominent in 

 front, completely hiding the pronotum ; the scutellum is also very- 

 large and gibbous. (Plate IV., fig. 42.) 



I. humilis, Mayr. (Plate IV., figs. 41 and 42.) 

 (Hypoclinca) Ann. Soc. Nat. Modena, vol. 3, p. 164, £ , 1868. Forel,. 

 Verh. Zool. Bot. Ges. Wien, vol. 58, p. 395, $, 1908. 

 Newall, Journ. Econ. Entom., vol. 1, p. 28, ? , 1908. 



£ . 3-2-3-5 mm. Brown or blackish brown ; legs, antennae and 

 mandibles paler. "Whole body covered with an exceedingly fine pale 



10 



