ANTS. 



FIG. 150. Worker of the Indian harvester, 

 Holcomyrmex scabriceps. (Bingham.) 



orous habit, for a carnivorous ant, used to collecting insects and crush- 

 ing their hard integuments with its powerful mandibles, is already fully 

 equipped with the apparatus necessary for dealing with seeds. And 

 although many harvesting ants have more convex mandibles and blunter 

 teeth than carnivorous species, it is impossible merely from examina- 

 tion of the mouthparts to ascertain whether an ant is granivorous or 

 not. It may be doubted, furthermore, whether there is such a thing 

 as a purely granivorous ant. There is clearly no advantage in an ant's 

 losing iN taste for the succulent tissues of other insects, although there 

 is an obvious advantage in its supplementing this diet with seeds during 



certain seasons of the year. 

 Indeed, many, if not all, of 

 the species mentioned in the 

 following pages are quite as 

 eager to secure insect food -as 

 seeds, especially while they 

 are raising their brood, and 

 unquestionably many ants that 

 are supposed to be exclusively 

 predaceous will, on closer 

 study, be found to be more 

 or less granivorous. 



If the foregoing considerations are correct, we should expect to 

 find the harvesting ants arising sporadically and often in distantly 

 related genera and species. This appears to be the case, for although 

 these insects belong to a single subfamily, the Mynnicinae, they occur 

 in at least three of the tribes, the Solenopsidii, the Tetramorii and the 

 Myrmicii. Among the Solenopsidii, however, only a single species of 

 Solcnopsis (S. geuiinata) is known to be granivorous, and only a por- 

 tion of the enormous genus Phcidolc comprises such species. The 

 small genus Pheidologcton is also granivorous. Among the Tetramorii, 

 Tetnunorhiiii cesf>ituni is only rarely and sporadically granivorous, 

 and this is perhaps true of a certain number of species of Mcranoplns. 

 Among the Myrmicii, Messor and Ischnomyruic.r comprise harvesting 

 species, whereas the species of the allied Stenainnia and . I ^Jucnoi/astcr 

 are predaceous. Holcomyrmex, now regarded as a subgenus of Mono- 

 morium, Pogonomyrmex, Oxyopomyrmex (with its subgenus Goni- 

 iniitna), which are closely related to Messor, and probably also Ory- 

 inynnc.r, are highly granivorous. 



The earliest of all recorded myrmecological observations undoubt- 

 edly relate to two harvesting ants, Messor barbarus and stmctor. The 

 former occurs throughout the Mediterranean littoral of Europe, Asia 



