CHAPTER XI.

THE HABITS OF INSECTS IN RELATION TO THE FERTILISATION OF FLOWERS.

Insects visit the flowers of the same species as long as they can.--Cause of this habit.--Means by which bees recognise the flowers of the same species.--Sudden secretion of nectar.--Nectar of certain flowers unattractive to certain insects.--Industry of bees, and the number of flowers visited within a short time.--Perforation of the corolla by bees.--Skill shown in the operation.--Hive-bees profit by the holes made by humble-bees.--Effects of habit.--The motive for perforating flowers to save time.--Flowers growing in crowded masses chiefly perforated.