BIOLOGIC KELATTONS BETWEEN PLANTS AND ANTS. 435 



disks. The same features are found in most of the species of that 

 genus, which are, without doubt, myrmecophilous. 



The utility of the auts for the Cecropia they inhabit may consist 

 entirely in the protection they afford. This protection would be not 

 only against plant-eating animals, but also against cochineals. We 

 may suppose that the latter are transported from the surface of young 

 buds, where they would be injurious to the normal development of the 

 leaves, to the cavities of the stem, where their injurious action would 

 be less. The ants here act like our gardeners who free hothouse plants 

 from infesting scale insects. But the honey dew of cochineals being 

 endowed with nutritive properties, the ants do not destroy them, but 

 merely transport them to a part of the plant where their life is more 

 compatible with the normal evolution of the vegetable. There would 

 thus be established a consortium of three members — between the plant 

 on one hand and the cochineals and the ants on the other. 



Upon the Gordia Gerascanthos we find enlargements of the branches 

 that are terminated by axes of inflorescence. Into these enlargements 

 the ants make openings, using, perhaps, the place where some little 

 bud is implanted. The cavity of the enlargment at first contains a 

 flocculeut tissue that the ants remove so that they may arrange within 

 the cavity disks like a sort of pasteboard. In this domicile the ants 

 pursue the raising of cochineals. It should be noted that these 

 enlargements do not appear to be constant in the species. 



In another species of the same genus, Gordia nodosa, the internodes, 

 especially those bearing the inflorescence, are enlarged and hollowed 

 near the insertion of the opposite leaves. The cavity communicates 

 with the outside by an orifice situated, not laterally, as in the preced- 

 ing species, but at its top. Both cavity and opening seem to be natural 

 and not affected by the agency of ants. In cavities not yet visited by 

 ants the internal surface is invested with stiff scattered ridges, some of 

 which hang over the opening. In this species the lodging organ is 

 formed hereditarily all ready for occupancy by the ants without any 

 preliminary labor on their part. The myrmecophilous features merely 

 outlined in the first species of Gordia would thus attain their perfec- 

 tion in the second and their origin be purely hereditary. This is an 

 excellent example of the fixation of a character primitively accidental, 

 and, so to speak, teratological. If the ants vary the place of penetrat- 

 ing the lodging cavity, the opening they make will not tend to become 

 hereditary — that is to say, to reproduce itself independently of their 

 action. This is the case, for example, in Acacia cornigera and the 

 Endospermums. But if the ants always make their opening at the 

 same point, the lesion tends to become a part of the morphologic plan 

 of the vegetable. The point of lesion in the ancestor becomes a point 

 of less resistance in the descendant — that is to say, a point where the 

 ants can make an opening with the greatest facility, as the wall of the 

 lodging organ would there be thin and easily perforable. In those 



