296 DARWINIANA. 



they remain unaffected. A touch shows that the glis- 

 tening drops are glutinous and extremely tenacious, as 

 flies learn to their cost on alighting, perhaps to sip the 

 tempting liquid, which acts first as a decoy and then 

 like birdlime. A small fly is held so fast, and in its 

 struggles comes in contact with so many of these glu- 

 tinous globules, that it seldom escapes. 



The result is much the same to the insect, whether 

 captured in the trap of Diongea or stuck fast to the 

 limed bristles of Drosera. As there are various plants 

 upon whose glandular hairs or glutinous surfaces small 

 insects are habitually caught and perish, it might be 

 pure coincidence that the most effectual arrangement 

 of the kind happens to occur in the nearest relatives 

 of Dionsea. Roth, a keen German botanist of the 

 eighteenth century, was the first to detect, or at least 

 to record, some evidence of intention in Drosera, and 

 to compare its action with that of Diongea, which, 

 through Ellis's account, had shortly before been made 

 known in Europe. He noticed the telling fact that 

 not only the bristles which the unfortunate insect had 

 come in contact with, but also the surrounding rows, 

 before widely spreading, curved inward one by one, 

 although they had not been touched, so as within a 

 few hours to press their glutinous tips likewise against 

 the body of the captive insect — thus doubling or quad- 

 rupling the bonds of the victim and (as we may now 

 suspect) the surfaces through which some part of the 

 animal substance may be imbibed. For Roth sur- 

 mised that both these plants were, in their way, pre- 

 daceous. He even observed that the disk of the 

 Drosera-leaf itself often became concave and enveloped 



