8o Flowers and their Unbidden Guests. 



course, are insects that, instead of being repelled, are to 

 be attracted, and to whom every possible facility is to 

 be given of rifling the nectar. It might, therefore, be ex- 

 pected, even a priori, that no impassable barriers would 

 be found inside the flowers on that short tract which 

 these welcome visitors must traverse either with their 

 proboscis or with the fore-part or whole of their body, 

 but merely such formations as would keep out unbidden 

 guests, and direct bidden ones on the right way. 



Soft hair-like trichomes are pre-eminently suited for 

 the construction of apparatus which will serve this 

 double function. When collected in large number, so 

 as to form trellises, "weels,"^ or similar aggregations, 

 these trichomes can easily render all access impossible 

 to one insect, while they offer no hindrance to a second, 

 whose longer thin proboscis can be readily thrust be- 

 tween the soft hairs, or whose greater strength enables 

 it to push open the latticed door. 



Such hair-like trichomes are, in fact, used in a vast 

 number of cases to form the internal defence of flowers 

 agaiQst unwelcome flying visitors. 



It must not, however, be inferred that every such 

 trichome, when found inside a flower, has this and no 

 other function ; nor yet that stems and leaves are 



• ^ [" Weel " is the technical name for those wicker baskets with 

 a small terminal opening that are naed by fishermen to catch eels, 

 etc. The arrangement of the stamens in the flowers represented 

 in Plate III. flg. 87, wUl give a tolerably correct idea of the shape 

 of such a weel. — Editob.] 



