FERTILIZATION. 



165 



flowers. Irregular flowers probably always are more or less 

 adapted to particular insect (or other) visitors. The adapta- 

 tions are so numerous that many volumes could be filled with 

 a description of them; — here only a 

 very few of the simpler ones will be 

 pointed out. Where there is a droop- 

 ing lower petal (or, in the case of a 

 gamopetalous corolla, a lower lip), this 

 serves as a perch upon which flying in- 

 sects may alight and stand while they 

 explore the flower, as the beetle is 

 doing in Fig. 146. In Fig. 147 one 

 bumble-bee stands with his legs par- 

 tially encircling the lower lip of the 

 dead nettle flower, while another 

 perches on the sort of grating made 

 by the stamens of the horse-chestnut 



flower. The honey-bee entering the violet clings to the 

 beautifully bearded portion of the two lateral petals, while it 

 sucks the nectar from the spur beneath. 



riG. 146. — A Beetle on the 

 Flower of the Twayblade. 

 (Enlarged four times.) 



Fig. 147. — Bees visiting Flowers. 



At the left a bumble-bee (European) on the flower of the dead nettle ; above a 

 similar bee in the flower of the horse-chestnut ; below, a honey-bee in the flower 

 of a violet. 



