A Monograph of the Formicidae of South Africa. Ill 



marching with the migratory columns of the Driver Ants,* but as 

 far as I am aware, the queens of the ants themselves have never 

 been so found, although the males have been obtained occasion- 

 ally under such circumstances. 



The three castes in this sub-family are so entirely different from 

 one another, that they were for a very long time classed under 

 different genera, and even under different families. The queens 

 are, moreover, excessively rare and known only in a few species, 

 and the males have been taken but rarely in company with their 

 workers, so that the resulting confusion in the classification of 

 the group has been and continues to be very great. 



There is a great general similarity amongst the workers of the 

 genus Dorylus, which becomes even closer within the limits of each 

 sub-genus. In the male sex, for lack of more patent distinctions, the 

 chief diagnostic characters are based on the structure of the geni- 

 talia ; but even there a beginner may very well have difficulties 

 in appreciating the subtle distinctions which separate the different 

 species. In fresh specimens the genitalia can be extracted very 

 easily, by squeezing the abdomen near the apex until they are 

 slightly extruded, when, with a pair of forceps, they may be 

 more fully drawn out. 



The queens of the Doryli are excessively rare, having been 

 described for only seven out of thirty-two known species. It is 

 probable that the total number of specimens of that sex in collections 

 barely exceeds a dozen. Unless the collector is so fortunate as to 

 discover the site of a nest of these insects he is hardly likely ever to 

 see a female specimen alive. Dr. Pe>inguey informs me that one of 

 the two females of Dorylus helvolus in the collections of the South 

 African Museum was obtained by him by placing a raw leg of mutton 

 in a manure heap in which he had previously noticed numerous 

 workers of the species (probably searching for the beetle larvae in 

 the heap). On examining the meat a little later the queen, together 

 with many workers, was found in it. 



The female of Bhogmus fimbriatus in the collection of Dr. H. 

 Brauns, of Willowmore, Cape Province, was found by Mr. G. A. K. 

 Marshall at Salisbury, S. Ehodesia. Mr. Marshall had his atten- 

 tion drawn to a hole out of which numerous males of the ant had 

 been seen to emerge, and by digging carefully and by following the 

 track of the larger tunnels over a considerable distance he was. 



* See " Ants and their Guests," by Father P. Wasmann, S.J., translated and 

 published in the Smithsonian Report, 1912, p. 455. 



