28o SAGACITY AND MORALITY OF PLANTS. 



to enter, but impossible to break out of. Into these, 

 small aquatic insects creep and die. Nearly every 

 '' bladder " on a plant is found to contain an insect, 

 generally a minute water-beetle or water-flea, the 

 latter being apparently the chief prey of the plant. 

 The mouth of this " trap " is • set with bristles, or 

 stiff plant -hairs, and there are others which point 

 inwards, so that insects easily get in but cannot get 

 out. Species of Bladderworts are distributed through- 

 out Europe and North America, as well as in the 

 West Indies and Brazil ; and Mrs. Mary Treat, 

 already mentioned for her experiments on other 

 plants, has watched the habits of a North American 

 species, Utidcidaria clandestina, very closely, and put 

 on record some very interesting facts in connection 

 with its mode of action. After speaking of water- 

 bears, water-fleas, etc., which had been admitted with- 

 in the " bladders " and kept there, she says : " So 

 these points were settled to my satisfaction — that 

 the animals were entrapped and killed, and slowly 

 macerated. ... I found almost every bladder that was 

 well developed contained one animal or more, or 

 their remains, in various stages of digestion. . . . 

 There was some variation with different bladders 

 as to the time when maceration or digestion began 

 to take place, but usually, on a growing spray, in 

 less than two days after a large larva was captured 

 the fluid contents of the bladder began to assume a 

 cloudy or muddy appearance, and often became so 



