494 ants' nests. 



attacked by parasites (ichneumon flies). The opening then closes, 

 but is subseijuently .opened again by the worker ants. This thinned 

 spot is an adaptation of the phint to the ant; it does not occur in the 

 Cecrojrid which is free from ants (that is to say, the corresponding bud 

 depression is not changed in texture and is not atrophied). On the 

 underside of the stem of the leaf of Cecropia adenopHs and others is a 

 peculiar hair cushion, which is constantly secreting albuminous, egg- 

 shaped particles (JVIiiller's corpuscles). Tliese secretions are eagerly 

 collected and devoured by the Azteca; they are one of their chief arti- 

 cles of food (as(;ertained through Fritz Miiller). The Cecropia which 

 is free from ants has none of ]\I idler's corpusck's. The species of (\cro- 

 pia are mucli frecjuented in Brazil by the leaf laitting ants (species of 

 Aitu) and are terribly injured by them, as has been repeatedly ascer- 

 tained by Belt and others. All tliose which contain Azteca colonies are 

 spared, because the vicious Azteca pursue the Atta furiously and drive 

 them away. 



All this is well ascertained. The i)lant, by an undoubted adaptation, 

 gives the ant food and lodging. The ant, in return, defends the plant 

 from its worst enemy. This symbiotic relation did not, of course, arise 

 all at once. Schimi)er found a Cecropia which is not inhabited by the 

 Azteca, until later, and probably also less regularly. This Cecropia has 

 also, it is true, thinned boring si)ots, but they are not formed until 

 later, and it has not as yet any Miiller's corpuscles. Last year in Bul- 

 garia 1 watched in oak woods and in old trees in general lAometopvm 

 microcephalum Pz., of Europe, which lives in trees. The trunks of the 

 trees are there, too, covered with ants, which attack fiercely all that 

 approach them. We have not in Europe any species of Attn that cut 

 leaves, but, on the other hand, we have so many more beetles and other 

 insects which delight to destroy the old oaks. I was charmed at seeing 

 near Aetos the finest oak forest that I have ever beheld, with real, superb 

 giants. Almost all of them were inhabited by lAoinetopiim colonies, 

 whose running workers covered all the trunks of the oaks. I have no 

 doubt that these fierce ants, whose carnivorous habits Emery has 

 described, drive away the enemies of the oak. The symbiotic relations 

 of the Azteca and the Cecropia were probably formed from these sim- 

 ple" relations. Liometopum lives only in trees; the trees, however, do 

 not display the least adaptation to that ant. 



Belt and Schimper have further proved, as to Acacia splia'rocepliala 

 WiLLD. and ^1. Hpadicigera Cham, and Schlecht, of Central America, 

 that ants of the genus rsendomyrma Lund not only always live in the 

 liollow thorns, but, owing to a peculiar adaptation of that plant greatly 

 resembling that of the Cecropia, find sugar and albuminous food iii)on 

 them. These two species of Acacia possess so-called extratloral necta- 

 ries, which furnish the ants with sugar, ambon the points of their leaves 

 Belt corpuscles rich m albumen (resembling the Miiller coi])uscles of the 

 Cecropia), which supply them with albumen. Still a closer direct obser- 



I 



