THE FLOWER AND THE BEE 



which bears near its base several whorls of small, naked 

 flowers, while its apical end is arched over the "pulpit" to 

 exclude rain. There is a small orifice at the base of the 

 spathe, where one edge overlaps the other, which serves for 

 the purpose of drainage. (Figs. 81 and 8*2.) 



The inner side of the spathe is smooth, shining, and very 

 sHppery, far more highly polished than the outside. When 

 Httle moth-like flies of the genus Psychoda rest on this polished 

 surface they are unable to gain a foothold and fall into the 

 chamber below. There for a time they are held prisoners, 

 since they cannot climb the smooth walls or the equally smooth 

 base of the spadix. The staminate flowers are visited first, 

 since they bloom first. As the spathes wither, their inner sur- 

 faces relax and become rougher, enabling the little visitors, now 

 loaded with pollen, to escape and fly to the pistillate plants. 

 The spathes of the latter wither less promptly, but from the 

 point of view of the "jacks" this is of little consequence, 

 since pollination has been effected; but it is fatal to many of 

 the flies which, unable to escape, perish in the chamber. 

 The arum family includes many tropical forms, like the 

 calla-lily; about the pollination of most of these very little is 

 known and undoubtedly many remarkable facts await dis- 

 covery. 



The peculiar-shaped Dutchman 's-pipe {Aristolochia sipho) 

 is pollinated in a manner very similar to that of jack-in-the- 

 pulpit; but the flowers are perfect, i. e., contain both stamens 

 and pistils. The calyx hangs downward, is about an inch and 

 a half long, bent like the letter S, constricted in the middle, 

 with the bowl-end of the pipe narrowed at the throat and very 

 smooth within. After they have once entered this tubular 

 passageway small flies are unable to fly or creep out until the 

 calyx withers. (Fig. 83.) 



168 



