HONEY ANTS. 377 



2. Many species have taken to eating and harvesting seeds a very 

 obvious adaptation to arid regions covered with a short-lived herba- 

 ceous flora, as is shown by the species of Pogonomyrmex in the New 

 World, Mcssor, Solenopsis and J'hciiiolc in both hemispheres, and 

 Holcoin\nnc.\', Oxyopomyrmex, doniounna, Meranoplus and Phcido- 

 loycton in the Old World (Chapter XYi). These ants still feed upon 

 insects when these are obtainable, but seeds furnish such an inexhaust- 

 ible and nutritious food supply that the habit of collecting and storing 

 them in the nests has become highly developed. 



3. A number of species, which have been described in detail in the 

 foregoing- pages, have taken to storing nectar and honey-clew in the 

 crops of a physiological caste, the repletes. 



4. Some ants (Attii) manage to live and thrive in very arid regions 

 because they cultivate and eat fungi. Although this habit, which has 

 been described in Chapter XVIII, probably originated in the luxuriant 

 rain-forests of the tropics, several fungus growing species have emi- 

 grated into the deserts of northern Mexico, western Texas and southern 



o 



Arizona. In these regions they can always obtain the vegetable debris 

 for the substratum on which to grow their fungi, and these delicate 

 plants can, of course, be successfully cultivated some distance below 

 the surface of the soil. These Attiine ants thus no longer depend on 

 the precarious food-supply of the desert, for in raising their crops they 

 are at a greater advantage than the farmer who makes his home in 

 the arid lands of the Southwest. 



