A Monograph of the Formicidae of South Africa. 165 



^ . The frontal carinae are nearly always separated, rarely close 

 together, divergent or slightly convergent behind and rarely lobed 

 anteriorly. 



$ . Usually winged ; not often ergatoid, generally larger than the £ . 



<$ . Anal segment with cerci ; armature usually partly exserted. 

 In a few species ergatoid and apterous. 



This sub-family is the largest of the five, comprising for South 

 Africa alone nearly 300 species, races, and varieties. Its classifica- 

 tion is attended with considerable difficulty, not only in the higher 

 ranks, but also often within the limits of the genera. If in some 

 genera, e. g. Monomorium, Cremastogaster, we make a visual examina- 

 tion of a series of forms which have been described as distinct, it may 

 not be difficult to perceive the individuality of each form or of each 

 of the links, sometimes very numerous, which connect up the extremes 

 of one or more species. That which enables us to appreciate the 

 distinctive character in such a case, is the sum total produced by a 

 combination of characters, often very slight, in the colour, punctura- 

 tion, gloss, and size of the insect. But although more or less readily 

 perceptible to the eye, the specific distinction of each form is far less 

 easily defined in words by the very reason of its composite nature. 

 This statement applies more particularly to the construction of 

 analytical keys having the succinct character which such aids to 

 rapid determination should possess. It is therefore essential that the 

 student should give careful attention to the remarks made on the 

 general structural features in the introductory paragraph to each 

 genus, since the characters used in the key are considered in direct 

 relation to the general morphology exhibited by the genus or by the 

 majority of its members. 



A far greater range of variation in habits and structure is shown in 

 this sub-family than in any of the others. The majority of the 

 species are mainly carnivorous, but there are some genera which are 

 graminivorous. Nearly all have a partiality for sugary substances, 

 and many tend aphides for the sake of the honey-dew excreted by 

 those insects. The tribe Attini of the New World is perhaps one of 

 the most remarkable of all, since it comprises the " leaf -cutting " or 

 " fungus -growing " ants, species which feed exclusively on fungi 

 cultivated in their nests. It is also to be noted that a very large 

 number of myrmecophilous insects are found in the nests of Myrmi- 

 cine ants. 



I have endeavoured to give with the descriptions of the species 

 those facts concerning their habits which have so far been ascertained, 

 but it must be admitted that such are painfully meagre, when not 



