■I.}, SPECtAL- RELATIONS. 21 



\Some always by the mouth of the flower, others 

 ■ always cutting a hole. He particularly mentions 

 . that this was the case with bees of one and the 

 same species, and infers, therefore, that the different 

 individuals differ from one another in their degrees 

 of intelligence ; these observations, though of course 

 not conclusive, are interesting and suggestive. 



Lastly, some insects confine themselves . to parti- 

 cular flowers. Thus, according to H. Miiller — 



Andrena florea 

 Halictoides 

 Andrena hattorfiana 

 Cilissa melanura 

 Macropis labiata 

 Osmia adunca 



Bryonia dioica 

 Species of Campanula. 

 Scabiosa arvensis. 

 Lythrum Salicaria. 

 Lysimachia vulgaris. 

 Echium. 



Another remarkable peculiarity of plants, .which 

 may I think possibly have reference to their rela- 

 tions with insects, is the habit of "sleeping," which 

 characterises certain species. 



Many flowers close their petals during rain, which 

 is obviously an advantage, since it prevents the honey 

 and pollen from being spoilt or washed away. Every- 

 body, however, has observed that even in fine weather 

 . certain flowers close at particular hours. This habit 

 of going to sleep is surely very curious. Why should 

 .flowers do so ? 



In animals we can understand it ; they are tired 

 and require rest. But why should flowers sleep .? 

 Why should some flowers do so, and not others .? 

 Moreover, different flowers keep different hours. The 

 Daisy opens at sunrise and closes at sunset, whence 



