ANIMALS AS FOOD, FOES, OH FRIENDS. 265 



each of which is tipped by a large gland (fig. 223). The 

 clear, glistening fluid, a large drop of which is secreted by- 

 each gland, is sticky enough to 

 entangle even insects of consider- 

 able size, which alight upon the 

 leaves. The viscid secretion 

 envelops the struggling insect,' 

 and at the same time the branches 

 of the leaves bend slowly inward 

 until more and more of the sticky 

 glands are thrust upon it. The 

 character of the secretion then 

 changes. It becomes 

 more watery and con- 

 tains substances which 

 soon digest the softer 

 parts of the body. 



Fig. 225. P'lG 226. 



Fig. 225. — A, blooming plant of Aldrovandia vesiculosa. Natural size. — After 



Drude. B, a single circle of leaves seen from the center above, showing stalk and 



two semicircular lobes. Magnified li diam.— After Caspary. 

 Fig. 226. — Transverse section through closed trap of Aldrovandia, showing on inner 



face long sensitive hairs and many absorption hairs. Only the central part is three 



layers of cells thick ; a broad margin is only one cell thick. Compare appearance in 



B, iig. 225. Magnified 20 diam.— After Caspary. 



These are absorbed, and play an important part in the nu- 

 trition of the plant. 



Dioncea (fig. 224) and its water mate, Aldrovandia (fig. 

 225), have leaves whose blades are somewhat like a spring 

 trap. The blade is two-lobed, with a hinge along the middle 



