1916.] 



The Pollination of Flowers in India. 



241 



nectary. The same orange colour marks the position of the 

 box on the outside, the other parts of the base of the flower 

 being grey. At Dinajpur (14-viii-09) where these observations 

 were made, there had been formed an abundance of fruit. Two 



Calliphora flies were seen in the flowers. 



Sphingid- flowers. 



Datura fastuosa, Linn., is certainly a Sphingid-flower ; but, 

 as it persists through the day, other insects may visit it. Its 



Fig. 2.— Flower of Datura fastuosa, reduced to nat. size, with sec- 

 tions indicating the nature of the deep pits containing the honey. 



large flowers open at nightfall, and last for 20—24 hours. When 

 they open, the anthers have already dehisced; these and the 

 stigma lie a little below the level of the mouth of the corolla. 

 Honev is plentiful in the lower part of five gradually contracted 

 channels made by the adhesion of the filaments to the corolla. 

 The figures on the preceding page show their nature and size. 



