'Blossom Hosts ami Insect Guests 



Fig. 



stigmas have withered when the pollen is shed — a 

 device which, acting in association with the little 

 ring of hairs, tells a strange story. 

 It is not my fortune to have seen 

 one of these singular blossoms, 

 // A ] but from the description of the 

 J process of fertilization given in 

 Hermann Muller s wonderful work, 

 aided by a botanical illustration of 

 the structure of the flower, I am 

 readily enabled to picture the pro- 

 gressive stages of the mechanism. 



In the first stage (B, Fig. 2), small flies with 

 bodies dusted with pollen from a previous arum 

 blossom are entering the narrowed tube, easily 

 passing through the drooping fringe of hairs. Nec- 

 tar is secreted by the stigmas, and here the flies 

 assemble, thus dusting them with pollen. Their 

 appetite temporarily satisfied, the insects seek es- 

 cape, but find their exit effectually barred by the 

 intruding fringe of hairs (C). In this second stage, 

 the stigmas, having now been fertiHzed, have 

 withered, at the same time exuding a fresh supply 

 of nectar, which again attracts the flies, whereupon, 

 as shown at D, the anthers open and discharge their 

 pollen upon the insects. In the fourth stage (E), 



