characters possessed by individual species among them but not common to the group — char- 

 acters which taken together are susceptible of the single interpretation that they are adap- 

 tations or adjustments for the capture and utilization of insects by the plants — there is the 

 further evidence that as insect traps they are astonishingly effective — that as traps, they work. 



Of all our pitcherplants, perhaps Sarracenia purpurea and Sarracenia psittacina are com- 

 paratively the least successful as insect traps. The sphagnum-embedded pitchers of purpurea, 

 however, functioning as water-filled pitfalls for attracted insects, or for those casually wander- 

 ing by, usually contain a few insects in their lower tubes, and sometimes they are crammed 

 with the bodies of beetles, crickets, or grasshoppers, when these insects abound. Although 

 the narrow-entranced pitchers of psittacina, may reveal little evidence, beyond an occasional 

 spider, of numerous captures, they are sometimes (and especially after the subsidence of 

 temporary floodwaters which have covered low-growing plants) literally stuffed with the 

 polished bodies of water beetles, held rigidly by the long elastic hairs which line the 

 narrow tubes. 



Although the hooded pitchers of Sarracenia minor, and the slender grouped pitchers of 

 S. rubra capture a wide range of insect species, yet these plants seem to specialize in the cap- 

 ture of ants, big and little, and their pitchers are often packed for several inches of their 

 length with the bodies of hundreds of ants, sometimes of a single abundant species from 

 some adjacent anthill. 



Of the larger pitcherplants such as S. flava^ sledgeij and drummondii, only those who have 

 walked through expanses of their tall pitchers, lifting their hoods and peering in at their 

 more recent captures, occasionally splitting open a mature pitcher and investigating its varied 

 contents, can appreciate the enormous number and variety of these captures, even in sur- 

 roundings which are not otherwise obviously rich in insect life. Here the entomologist may 

 find many species: beetles, large and small, bees, wasps, parasitic Hymenoptera, moths, flies, 

 grasshoppers, even such actively flying insects as butterflies and dragonflies, and including 

 species whose local presence he may not have even suspected. Spiders, living and dead, are 

 frequent occupants. Not rarely, little green tree toads sit by day within the mouths of the 

 larger pitchers; but their bones, and those of the slender "chameleon" lizards, embedded among 

 the fragmentary insect remains below, bear witness to the fact that even these vertebrates 

 are not always successful in escaping the trap when once they have ventured within the 

 pitcher's mouth. 



Similarly, the pitchers of Chrysamphora (Darlingtonia^, from the first hours of the opening 

 of their cobralike hoods, begin to capture insects, until their great tubes are stuffed with 

 insect remains, which in variety form almost a cross-section of the insect fauna of the plant 

 habitat. This western species seems to lack the digestive enzyme of Sarracenia, and soon its 

 accumulated insect captures are converted into an ill-smelling mass, even contaminating the 

 air of their mountain bogs with the odor of decay. 



The pitcherplants are real insect traps. 



2.6 



