INTERRELATIONS OF INSECTS 341 



Though the diverse relations between myrmecophiles and ants 

 are but partially understood, these aliens may for convenience 

 be considered under five groups : captives, guests, visitors, in- 

 truders and parasites. 



Captives. Besides enslaving other species, as already men- 

 tioned, ants make use of aphids and some coccids for the sake 

 of their palatable products. The attendance of ants upon col- 

 onies of plant lice is a common occurrence and one that repays 

 careful observation. With the aid of a hand-lens, one may 

 see the ants hastening about among the plant lice and patting 

 them nervously with the antennae until at length some aphid 

 responds by emitting from the end of the abdomen a glistening 

 drop of watery fluid, which the ant snatches. This fluid, con- 

 trary to prevalent accounts, is not furnished by the so-called 

 honey-tubes of the aphid, but comes from the alimentary canal ; 

 the " honey-tubes " are glandular indeed, but are probably 

 repellent in function. In some instances ants give much care 

 to their aphids, for example covering them with sheds of mud, 

 which are reached through covered passageways. More than 

 this, however, some ants actually collect aphid eggs and pre- 

 serve them over winter as carefully as they do their own eggs. 

 In one such instance, Lubbock found that the aphids upon 

 hatching, after six months, were brought out by the ants and 

 placed upon young shoots of the English daisy, their proper 

 food plant. In our own country, as Forbes has discovered, 

 the eggs of the corn root louse (Aphis maidiradicis) are col- 

 lected in autumn by ants (especially of the genus Lasius} and 

 stored in the underground nests. In winter, the eggs are taken 

 to the deepest parts of the nest, and on bright spring days they 

 are brought up and even scattered about temporarily in the 

 sunshine; while if a nest is opened, the ants carry off the aphid 

 eggs as they would their own. In spring, the ants tunnel to 

 the roots of pigeon grass and smartweed, seize the aphids and 

 carry them to these roots, and later to the roots of Indian 

 corn. Throughout the year the ants exercise supervision over 

 these aphids; occasionally, as Forbes says, an ant seizes a 



