BIOLOGIC RELATIONS BETWEEN PLANTS AND ANTS. 433 



stem have a peduncle that turns upon itself with a spiral coil opposite 

 the most swollen portion of the pitcher. Its cavity does not extend 

 beyond the enlarged portion of the peduncle. The leaves situated at 

 other levels of the stem have a straight peduncle joining the pitcher 

 at right angles and enlarged at the junction.^ The enlargement is hol- 

 low and also has an opening where it touches the pitcher. In neither 

 of these forms is there any communication between the cavity of the 

 pitcher and that of the peduncle. The axis of the male inflorescence 

 is traversed by a median canal communicating with the exterior by 

 several openings, which, like those made in the peduncle, have every 

 appearance of being the work of ants that inhabit the cavities of those 

 organs. We are unfortunately not informed whether the peduncles of 

 hothouse plants have the enlargements so characteristic of the wild 

 form, or whether the perforations are wanting if ants are absent. It is 

 to be supposed, reasoning from analogy, that the enlargements are con- 

 stant, but the perforations are the work of ants which have removed from 

 the cavities of the peduncle and the inflorescence a spongy tissue like 

 that belonging to the Acacia cornigera. As to the first cause of the 

 formation of these peduncular enlargements we may perhaps find it in 

 the bites of the ants. This differentiation, traumatic in its origin, 

 might become hereditary in the course of time. 



If it be true that the Nepenthes are really carnivorous plants (which 

 in the present state of our knowledge seems doubtful), the species may 

 utilize in two ways the hospitality it proffers to ants. Those insects may 

 defend it against plant eaters, and if while running about the surface 

 of their host they chance to fall into the traps formed by the pitchers, 

 the plant may use their carcasses for food. The ants would thus serve 

 the plant both for defense and for prey. (PI. XIX.) 



The species of Kibara (K. formicarum and K. hospitans), a genus of 

 the family Monimiacea?, have perforated internodes, either solid or hol- 

 low, that are visited by ants (Hypoclinea scrutator). Within the hollow 

 internodes are found numerous individuals of a species of cochineal 

 (Myzolecanium Kibarce) that has a very well developed rostrum. 

 Although it is not possible to determine in the dried specimen the 

 presence of an excretory apparatus, there is reason to suppose that 

 these insects give out a sugary liquid sought for by the ants. Bio- 

 logical relations ought then to exist between these inhabitants of the 

 Kibaras, and it is not probable that the cochineals enter by themselves 

 the cavities of the internodes. They have doubtless been conveyed 

 there when young by the ants and there finish their development, the 

 pregnant females attaining such dimensions that it is impossible for 

 them to leave the cavity by the orifice of entrance. The ants have, 

 then, undertaken the raising of cochineals within the internodal cav- 

 ities of the Kibara. The orifices of entrance to these stables seem 

 certainly to be their work. In fact, at the base of the internode there 

 are found small, superficial perforations, apparently the result of 

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