* 



232 



MISSOURI BOTANICAL GARDEN. 





B 



mit 



nbeladenen 



emge 



habe. Bei dieser Arbeit verweilen diese Bienen allerdings 

 langereZeit in jeder Bliithe." Another group of insects 



etimes devour them entirely, 

 wasps on the flowers of T. 



attack the stamens 

 and he often found 



d 



large 



Cytonia and Bup 



Coleopt 



be sought in the handsome flowers of the Melastomataceae. 

 The attractiveness of the stamens for insects and the secre- 

 tion of nectar by these organs in Purpurella led to a 

 microscopic examination of these parts of T. gloriosa with 

 the demonstration of an abundance of sugar which, how- 

 ever, is never excreted in visible form. In many species 

 of Tibouchina a nrononnmd change j n color in different 



pronounced 



ages of the flower is demonstrable, and of this several 

 examples are given. 



A note from Mr. Willis on the pollination of the Melas- 



Exacu 



Solanum-Cassi 



Br 



ledifoli 



to be adapted to pollination by birds. 



The depth of the nectar and the size of the opening in 

 connection with the consistency of the perianth and the 

 position of the flower tend to exclude insect pollinators 

 with the exception of the Sphingidae, and these are hardly 

 to be considered on account of the lack of perfume in the 

 flowers and the insuffiency of a soft proboscis for the 

 ejection of the pollen from the 



pollen from the anthe 

 IthampJiomicron herrani and 



As 



Melallura tyrian- 

 thina. These inserted their beaks into the small opening 

 of the flower for the purpose of obtaining insects or nectar 

 secreted by the filaments and forced a puff of pollen from 

 the bellows-like anthers by pressing them with the tip of 

 the beak. By pressing the elastic anther wall with a 

 rounded match the pollen may be ejected for a distance of 

 three centimeters, after which the wall assumes its original 



