BEHAVIOR OF ANTS AND MYRMECOPHILES 439 



to others of the same colony it does not generally associate with 

 one particular individual more than with others, but Ernst 

 observed that two isolated ants showed an attraction for each 

 other, remaining together much of the time, and when one 

 died the other showed signs of much uneasiness. In the case 

 of two females and a worker of Tapinoma erraticum which were 

 kept isolated, the former seemed much disturbed at the death 

 of the latter, licking and feeling of the body. These actions 

 were more pronounced in one of the females than in the other. 

 A female of Formica rufibarbis, after killing two females of F. 

 pratensis, received a third without signs of hostility, and the 

 two lived amicably together. Different species of ants vary in 

 their aptitude tor making friends, and the females form the 

 association more quickly than the males. Ernst observed a 

 Dipteron, Farnia manicata, in company with ants, in the act 

 ot "milking" aphids and sipping up the drop of exuded liquid. 

 The fly stroked the gaster of the aphid with its forefeet, which 

 are provided with a brush of hairs. 



Besides ants and this interesting dipteron, a Lycaenid but- 

 terfly in Ceylon is known to milk aphids. 



Hungerford and Williams (17) in Kansas observed that 

 the gieat majority of nests of Pogonomyrmex occidentalis have 

 their openings on the southeast side or more toward the east. 

 A heliotropic influence is suggested. 



A special disgust was shown by the workers toward certain 

 Scaraboeid beetles. When one of these w T as placed on the nest 

 it was attacked by as many as ten workers, and when it had 

 ceased struggling was carried to a distance of ten or twelve 

 feet from the cone. The ant was seen carrying the myrme- 

 cophilous beetle Cremastocheilus saucius. 



Hunter (18) notes that in fields infested with the agiicultural 

 ant, Pogonomyrmex barbatus var. molejaciens, the plants in a 

 circle just outside the cleared areas of the nest grow with in- 

 creased luxuriance, a condition he thinks, caused by the loosen- 

 ing of the soil through the underground tunnels of the ants, 

 which has somewhat the effect of deep plowing. This increased 

 grow r th is, in a way, compensatory for the cleared areas which 

 the ants make, and though it does not entirely offset the loss 

 caused by them, reduces the economic importance of the insect. 



