AMMOCH/ETVE. 1 87 



philous ants have taken to harvesting and eating seeds. Others, 

 like the honey ants (American species of Myrmecocystus, Austra- 

 lian Camponotus and Meloplwrus), still collect plant juices with 

 avidity, but as such liquids are scarce or only temporarily abun- 

 dant, they store them in the distensible crops of certain workers, 

 which thus function as living bottles (repletes, or plerergates). 

 Still other ants, like many Myrmecocysti, both in the Sahara and 

 in the deserts of the southwestern States, have exaggerated the 

 primitive entomophagous habit and have become very agile, pred- 

 atory hunters. 



As the circumoral macrochaetae occur in desert ants that have 

 specialized in each of these three directions, it is difficult to de- 

 tect any relation between the development of such structures and 

 the character of the food. But inasmuch as the food of all ants 

 really consists exclusively of liquids either imbibed directly or 

 carefully expressed from moist solids, I was led at first to adopt 

 the following hypothesis : When the mandibles are wholly or 

 partially closed, the macrochaetae are seen to form a crate or lat- 

 tice-work, enclosing a lenticular space on the ventral side of the 

 head. A drop of liquid carefully introduced into this space by 

 means of a fine pipette will fill it and hang securely suspended 

 from the flat or concave gula, with the spherical surface supported 

 by the hairs of the crate. This experiment led me to the opinion 

 that the hairs might be used for one or both of two purposes : 

 first, to retain regurgitated drops of liquid and prevent their fall- 

 ing to the earth while the ants are feeding their larvae or one an- 

 other ; and second, to enable the ants to collect from the stones 

 and desert plants drops of rain water and to carry these to their 

 nests. The hairs would certainly seem to be admirably adapted 

 to both of these liquid-saving functions. This hypothesis seemed 

 to be confirmed by the following observation on our northern 

 Stenamma {ApJicenogaster') fulvum, published by Miss Fielde : l 

 " I have observed that these ants, like the termites, are able to 

 carry water for domestic purposes. They probably lap the water 

 into the pouch above the lower lip and eject it at its destination. 

 A hundred or two ants that I brought "in and left in a heap of 

 dry earth upon a Lubbock nest, during the ensuing night took 



l " Further Study of an Ant," Proc. Acad. Nat. Sci. Phila., 1901, pp. 521-544. 



