326 WHEELER— ANT LARV^.- 



be shown that trophallaxis, originally developed as a mutual trophic 

 relation between the mother insect and her larval brood, has ex- 

 panded with the growth of the colony like an ever-widening vortex 

 till it involves, first, all the adults as well as the brood and there- 

 fore the entire colony ; second, a great number of species of alien 

 insects that have managed to get a foothold in the nest as scaven- 

 i. e., other species of ants (social parasitism) ; fourth, alien insects 

 gers, predators or parasites (symphily) ; third, alien social insects, 

 that live outside the nest and are "milked" by the ants (tropho- 

 biosis), and, fifth, certain plants which are visited or sometimes 

 partly inhabited by the ants (phytophily). In other words the -ants, 

 have drawn their living environment, so far as this was possible, 

 into a trophic relationship, which, though imperfect or one-sided in 

 the cases of trophobiosis and photophily, has nevertheless some of 

 the peculiarities of trophallaxis. A brief sketch of each of these 

 five expansions, indicated as annular areas in the accompanying 

 diagram (Fig. 12), may not be out of place. 



I. There is a very close resemblance between the behavior of adult 

 ants towards one another and their behavior towards their young. 

 The adults feed one another with regurgitated food or even wath 

 secretions as is the case with Crematogasfcr (Physocrema) iuflata, 

 an Indomalayan species, the workers of which have great sugar- 

 glands in the back of the thorax. Many ants transport each other, 

 and the transported ant assumes a quiescent, larval or pupal attitude. 

 This is best seen in certain Ponerinje, c. g., in the species of Lobo- 

 pclfa, which carry their males under the body as if they were 

 larv?e or pup?e. On such occasions the males keep their legs and 

 antennae in the pupal position. Moreover, when the food-supply 

 of the colony is cut off ants often devour other ants of the colony 

 as if they were larvae or pupre. The largest workers (soldiers) are 

 eliminated first, either because they represent more stored food or 

 because their continued life in the colony constitutes a greater drain 

 on the food, resources, or for both reasons. Some years ago I re- 

 corded an instance of this behavior in an Arizona ant, which I called 

 Phcidole militicida, because it regularly kills and eats all the large- 

 headed soldiers in the colony during the winter when the food supply 

 is very limited. In artificial nests of Caiiipuiwlits, which has poly- 



