ANTS. 



those of all other genera in this respect ; in fact, the yellow, sub- 

 terranean ants of the subgenus Acanthomyops, which is peculiar to 

 Xorth America, live exclusively on the excrement of root-aphids and 

 coccids. 



The behavior of ants in the presence of aphids has been observed 

 by P. Huber (1810), Forel (1874), Witlaczil (1882), Lubbock 

 (i888a). Biisgen (1891), Lichtenstein (i87/-'8o), Forbes (1894. 

 1905, 1906), Del Guercio, Kolbe (1888), Shouteden (1902), Mord- 

 wilko (1896, 1901, 1907), and others too numerous to cite. One of 

 the best of the early accounts of this behavior is that of Huber (p. 181 

 ct scq.) : " A thistle branch was covered with brown ants [Lasius niycr \ 

 and aphids. I observed the latter for some time, in order, if possible, 

 to ascertain the precise moment when they emitted this secretion from 

 their bodies ; but I remarked that it exuded very rarely of itself, and 

 that the aphids, when separated from the ants, discharged it to a dis- 

 tance, by making a movement like a sudden jerk. 



' \Yliy did nearly all the ants that were climbing about on the 

 stems, have their abdomens distended as if with some liquid? This 

 question I was able to answer by watching a single ant, whose exact 

 method of procedure I will endeavor to describe. I saw her first crawl 

 over some aphids without pausing and without disturbing them ; but 

 she soon halted near one of the smallest and seemed to caress its 

 abdomen, stroking it alternately first with one and then with the other 

 antenna. I was surprised to see the liquid escape from the aphid's 

 body, and the ant seize and imbibe the droplet at once. Her antenna? 

 were thereupon applied to another much larger aphid, which, on being 

 caressed in the same manner, voided a larger drop of the nutrient 

 liquid. The ant advanced to seize it, and then moved on to a third 

 which she caressed in the same manner. The liquid was voided imme- 

 diately and received by the ant. She moved on ; a fourth, probably 

 already exhausted, refused to respond to her solicitations and the ant. 

 probably divining that she had nothing to expect, quitted this aphid for 

 a fifth from which I saw her obtain a further supply of food. 



" A few such repasts are quite sufficient, and the satiated ant returns 

 to the nest. Thereupon I watched the other ants that had remained 

 behind on the thistle, and they were seen to present the same scene. I 

 always noticed that the arrival of the ants and the stroking of their 

 antenna? preceded the evacuation of the liquid, and that the attitude 

 of the plant-lice, with their heads directed downward, seemed to be 

 assumed for this very purpose. I witnessed this remarkable procedure 

 thousands and thousands of times ; it was always employed by the ants 

 with the same success whenever they wished to obtain food from the 



