( 155 ) 



A short time ago Ule ^) has drawn attention to this as a result of 

 his investigation of American plants. 



3. Is sugar secreted in all nectaries? 



This is not the case ; in some nectaries I could detect no secretion 

 even after they had stayed for a long time under a bell-jar; this 

 w^as the case e.g. with the leaves of Gmelina aslatica. Consequently 

 they are not frequented by ants, although these insects always occur 

 on thé similarly shaped but strongly secreting nectaries of the calyx. 



The quantity of the secreted substances moreover fluctuates with 

 the same nectaries of the same plant and depends on many external 

 and internal influences. 



4. Are all the pi'oducts secreted by the nectaries always and 

 eagerly consumed by the ants? 



Evidently this also is not always the case, for whereas the necta- 

 ries of some plants are constantly frequented by ants, with others 

 the nectaries so to say overflow, without a single animal visiting 

 them. (So with some species of Fassijlora). 



5. At what age of the organs do the nectaries secrete sugar? 



As a rule the nectaries of the inflorescences cease to secrete as 

 soon as the flowers are opened ; those of the leaves even only 

 functionate in the youngest stages of development. 



6. Are the ants that frequent the plants with nectaries hostile 

 towards other visitors? 



Although I daily watched the behaviour of the ants with the 

 extrafloral nectaries for hours, I have never observed that they 

 hindered other animals in any way. On the Lujj'a species one may 

 see the ants at the nectaries peacefully busy by the side of a species 

 of beetles which does great damage to the plant by eating leaves 

 and buds. 



The results of my investigations of some wild plants in Java in 

 their natural sites agreed entirely with those obtained in the Buiten- 

 zorg Botanical Garden. 



Exactly those species of ants that occur on the so-called "ant- 

 plants" of the Indian archipelago, seem to belong to the harmless 

 ones; the dangerous species with powerful mouth-apparatus, e.g. 

 those which are called sennit ranggrang in West Java and according 

 to Dr. VoRDERMAN are used by the Malay for defending Mango trees 

 against beetles, are carnivorous. So these ants have to be specially 

 allured by hanging animal food (dead leguans) in the trees to be 

 protected. 



1) Englers Bot. Jahrbücher. Heft III, Bd. 37, 1906. 



