Welcome and Unwelcome Guests. 33 



were not protected against the prejudicial attacks of 

 animals, and yet attracted them by dainty and in- 

 viting food, must sooner or later have been exter- 

 minated, as they would have been overgrown and 

 supplanted by others, the blossoms of which pos- 

 sessed means of self-protection, and therefore stood 

 at a decided advantage. 



Animals and plants however do not always stand in 

 the relation of enemies and prey. On the contrary, it 

 is well known that many plants derive great advantage 

 from the visits of animals, nay, even sometimes from 

 their very attacks, since often it is only by such agencies 

 that the stigma can be properly fecundated.^ 



Consequently many flowers have special arrange- 

 ments to allure insects to visit them. These allure- 

 ments, it is true, are meant only for certain insects ; for 

 many kinds, owing to the conformation of their bodies, 

 would be of no use, but would rather be prejudicial, 

 in the ways already mentioned. 



In relation to the vegetable world, or more correctly, 

 in relation to each individual form of plant, animals may 

 be divided into welcome invited guests, whose visits 

 are of advantage, and into unwelcome uninvited guests, 

 whose visits are prejudicial, or at least of no advantage. 



These invited and uninvited guests are of endless 



variety ; and corresponding to them, and of an almost 



^ The beuefita conferred by animals on plants in regard to 

 the dispersal of seeds must he passed over here with this cursory 

 allusion. 



