ANIMALS AS FOOD, FOES, OR FRIENDS. 343 



foothold to an insect attempting to crawl out ; or covered by 

 stiff, downward-pointing hairs to oppose its passage; or the 

 side of the tube is filled 

 with thin translucent spots 

 through which the cap- 

 tives vainly strive to fly, 

 while the real opening is 

 concealed. By one or 

 other of these means the 

 prey is prevented from 

 escaping, and sooner or 

 later is drowned in the 

 liquid. In this liquid 

 digestive enzymes or bac 

 teria quickly dissolve the 

 softer parts of the insect 

 bodies, and the soluble 

 portions are absorbed by 

 the leaf. 



{b) The bladderwort, 

 which abounds in quiet 

 pools, furnishes an ex- 

 cellent illustration Of traps Flr - 382— A, trumpet-shaped sessile leaf of Sar- 

 racenia variolaris, snowing thin membran- 

 (fiUS. 78':, ^84). UnOll m,s windows in the meshes of the veins of 

 \ © o 01 o ~tj 1 the hood which arches over the mouth of the 



the leaves are numerous trumpet. /;, cup-shaped petioied leal .if .\v- 



pentkes villosa, with elevated lid and margin 

 minute bladders, each ribbed. One-third natural size.— After Kerner. 



with a small opening about which divergent hairs serve as 



guides to the entrance. The entrance is lightly closed by a 



flap of membrane, which is readily lifted by minute water 



animals. After they have passed through the opening the 



membrane drops behind them, ami is stiff enough to prevent 



their escape. Death ensues sooner or later, and absorbing 



hairs on the inner face of the trap take up the nutritive 



materials. 



