INSECTS AND FLOWERS 191 



obtain a feast, but incidentally become dusted 

 all over with pollen grains. Directly the pollen 

 is all shed, the downward pointing hairs wither 

 away, leaving a clear passage through which 

 the midges are free to make their escape and 

 fly away to another plant, where they will repeat 

 the process of cross-fertilization. If the stamens 

 of the Cuckoo-pint were the first to ripen, the 

 pollen would fall on to the stigmas of the same 

 plant, but by this device of alluring the midges 

 and holding them prisoners while the stigmas 

 first ripen and are fertilized with the pollen 

 brought from another plant by the midges, the 

 Cuckoo-pint secures with certainty the advantage 

 of cross-fertilization. 



The common English spotted Orchis is 

 another plant affording an interesting example 

 of extreme ingenuity in obtaining the benefit of 

 cross-fertilization. The flowers of Orchids are 

 all remarkably complex, many are most ex- 

 traordinary in appearance, while others may be 

 numbered amongst the handsomest flowers in 

 the world. In more than two-thirds of the 

 Orchids, one of the petals differs considerably 

 from the others in shape, being larger and more 

 conspicuous in coloration, this is called the lip 

 or labellum, and forms a most attractive alighting 

 place for insects. This petal is at first directed 

 upwards in the bud, but in the majority of the 

 Orchids, as the flower develops, the ovary 

 undergoes a spiral twisting which brings the 

 lip-petal below so as to serve as a resting-place 

 for insects alighting in search of honey. Except 

 in the flower of Cypripedium, there is only one 



