248 A BOOK OF INSECTS 



may be in part rain-water, but is largely the secretion of 

 special gland- cells. When insects or other small creatures 

 fall into this bath they are drowned, and their soft tissues 

 are slowly digested and absorbed by the plant. 



That these death-traps have a flower-like appearance, 

 being daintily coloured and marked with " honey guides," 

 and that they secrete a copious nectar from the parts 

 surrounding their apertures, are among the most astonish- 

 ing facts of life. Insects are completely deceived by the 

 resemblance and creep into the pitchers, or fly to them 

 from a distance, with the same alacrity that they display 

 in their intercourse with flowers. They feast upon the 

 nectar, then wander or slip downwards until they reach 

 the water. Winged species often make desperate efforts 

 to extricate themselves by flight ; but they buffet against 

 the sides of the pitcher, or knock against the lid-like leaf 

 above the aperture, until they are exhausted. They seldom 

 make good their escape. 



The true pitcher-plants of the genera Nepenthes, Sar- 

 racenia, and their allies, are tropical or sub-tropical ; but 

 we have in Britain an interesting water-plant, the bladder- 

 wort ( Utricularia), which captures its prey in a somewhat 

 similar manner. In this case the traps are little bladder- 

 like structures, the orifices of which are closed by valves 

 so contrived that tiny aquatic animals can enter, but not 

 return. Why these creatures press through the fatal door 

 has not yet been fully explained ; but it is a fact that each 

 bladder usually contains a little crowd of prisoners, which 

 slowly perish and become food for the plant. The majo- 

 rity of the victims are minute crustaceans — " water fleas " 

 and the like ; but a considerable number are gnat larva 

 and other small insects. 



The leaves of the butterwort {P'niguicula) are sticky, so 

 that small insects settling thereon are held fast. After a 



