284 Adjustment to Conditions of Aquatic Life 



hairs, each with a pearly drop of secretion at its tip 

 sparkling in the light, like dew, they are very attractive 

 to look upon. The insect that makes the mistake of 

 settling upon one of these leaves is held fast by the tips 

 of the hairs it touches: the more it struggles the more 

 hairs it touches, and the more firmly it is held. Ere it 

 ceases its struggles all the hairs within reach of it 

 begin to bend over toward it and to apply their tips to 

 the surface of its body. Thus it becomes enveloped 

 with a host of glands, which then pour out a digestive 

 secretion upon it to dissolve its tissues. When digested 

 its substance is absorbed into the tissue of the leaf. # 



The pitcher-plant, Sarracenia, captures insects in a 

 different way. Its leaves are aquatic pitfalls. They 

 rise usually from the surface of the sphagnum in a bog 

 (see fig. 207 on p. 350) on stout bases from a deep seated 

 root stalk. They are veritable pitchers, swollen in the 

 middle, narrowed at the neck and with flaring lips. 

 The rains fill them. Insects fall into them and are 

 unable to get out again; for all around the inner walls 

 in the region of the neck there grows a dense barrier of 

 long sharp spines with points directed downward. 

 This prevents climbing out. The insects are drowned, 

 and their decomposed remains are absorbed by the 

 plant as food. 



It is mainly aerial insects that are destroyed, flies, 

 moths, beetles, etc. ; and we should not omit to note in 

 passing that there are other insects, habituated to life 

 in the water of the pitchers, and that normally develop 

 there. Such are the larvae of the mosquito, Aedes 

 smithi, and of a few flies and moths. 



The bladderworts (Utricularia) are submerged plants 



that float just beneath the surface. On their bright 



green, finely dissected leaves are innumerable minute 



traps (not bladders or floats as the name of the plant 



' ^ having the appearance shown in the accom- 



