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Article XXIV.— AN ETHOLOGICAL STUDY OF CERTAIN MAL- 

 ADJUSTMENTS IN THE RELATIONS OF 

 ANTS TO PLANTS. 



By William Morton Wheeler. 



Plates LXIII-LXVIII. 



Much has been written concerning the mutual helpfuhiess of 

 certain species of ants and plants, but very little attention has been 

 bestowed, on the cases in which these organisms live together in a stat e 

 of imperfect adaptation or antagonism. And yet such conditions may 

 be expected to exist as the preliminary stage, if nothing more, in the 

 course of development leading to such complete and hai'monious 

 adjustments as we witness in the symbiosis of certain ants, like the 

 American Attii, with the fungi which they not only systematically 

 cultivate but carefully transmit from mother to daughter colonies 

 generation after generation. In the following article I have collected 

 a few cases which seem to me clearly to prove the existence of a 

 struggle between the ants and their plant environment, a struggle 

 in which the ants, notwithstanding their notorious adroitness in 

 surmounting obstacles to their welfare, seem always to succumb. 



I. THE mound-building ANT AND THE HAIR-CAP MOSS. 



Some months ago Mr. W. D. W. Miller of the American Museum 

 of Natural History called my attention to a beautiful colony of the 

 mound-building ant of the Alleghenies (Formica exsectoides) near 

 Scotch Plains, New Jersey. This colony, which Mr. Miller visited 

 with me during May and June, is situated in a wood on fiat clayey 

 soil, at an altitude of about 150 meters. The nests, forty to fifty in 

 number, are scattered over an area of less than a square kilometer 

 and are all built in open, sunny clearings among the trees. There 

 are nests in all stages of growth, from their first inception to old 

 extinct mounds covered with moss and other plants. The worker 

 ants, in full possession of the surrounding woods, are everywhere to 

 be seen, running about on the ground in search of dead and disabled 

 insects, and climbing the trees and bushes for the purpose of collecting 

 the honey-dew from the droves of aphids and membracids. Though 

 less numerous, the nests near Scotch Plains compare very favorably 

 in size with those of the famous colony near Hollidaysburg, Penn- 



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