wings, legs, eyes, antennae, whose parent must have searched out the minute egg of Exyra 

 and whose entire life cycle must have been completed within the eggshell's bounds. Other 

 and larger parasites, some wasplike, some two-winged flies, are fatal to the larvae of Exyra, 

 and perhaps the brief exposure of these larvae when occasionally they move from pitcher to 

 pitcher may give opportunity for the parent parasite to deposit its egg on the otherwise 

 well-hidden caterpillar. The larvae of the pitcher-robbing Sarracenia flies would seem reason- 

 ably safe from parasitic attack; but their brown puparia often yield not flies, but whole flocks 

 of little wasplike parasites which emerge in a procession through holes gnawed in the rigid 

 walls of a puparium. The rootborer, Papaipema, also has its parasites. The larvae of the Sar- 

 racenia wasp in their well-packed cells are not immune; nor are parasites their sole danger; for 

 before the rightful occupant of a cell has had time to consume its store of food, this is often 

 plundered by ants or by other insect scavengers. Ants, too, though among the more frequent 

 victims of the leaf trap, sometimes actually build their nests in a dry pitcher (do they drain 

 it first?), and even construct a paperlike narrow-entranced door across its mouth, excluding 

 other insects. Thus all sorts of complications arise, when insects having conflicting interests 

 attempt to occupy the same pitcher. Not rarely, an Exyra caterpillar, closing a pitcher for its 

 own use and thus preventing the entrance of other insects, incidentally starves the Sarcophaga 

 larva already ensconced below and dependent upon the entrance of fresh victims for its food. 



So, from our observation of the complicated relationships which reveal the pitcherplants 

 as focal points of contact between the plant and animal worlds, emerges a more vivid reali- 

 zation that in nature each plant, each animal species, exists for itself alone; that its whole 

 economy of life relates to its own growth, its own safety, its own specific survival; and that 

 in the attainment of these ends, its environment is not confined to the obviously imma- 

 nent, but that its expanding circles of influence fade from our view into the distant and 

 the remote. 



33 



