CHAP. XI. PERFORATION OF THE COROLLA. 429 



alluded to bees biting holes in flowers for the sake of 

 obtaining the nectar. They often act in this manner, 

 both with endemic and exotic species, in many parts of 

 Europe, in the United States, and in the Himalaya ; 

 and therefore probably in all parts of the world. The 

 plants, the fertilisation of which actually depends on 

 insects entering the flowers, will fail to produce seed 

 when their nectar is thus stolen from the outside ; and 

 oven with those species which are capable of fertilising 

 themselves without any aid, there can be no cross- 

 fertilisation, and this, as we know, is a serious evil 

 in most cases. The extent to which humble-bees 

 carry on the practice of biting holes is surprising : a 

 remarkable case was observed by me near Bourne- 

 mouth, where there were formerly extensive heaths. 

 I took a long walk, and every now and then gathered 

 a twig of Erica tetraliae, and when I had got a hand- 

 ful examined all the flowers through a lens. This 

 process was repeated many times ; but though many 

 hundreds were examined, I did not succeed in finding 

 a single flower which had not been perforated. 

 Humble-bees were at the time sucking the flowers 

 through these perforations. On the following day a 

 large number of flowers were examined on another 

 heath with the same result, but here hive-bees were 

 sucking through the holes. This case is all the 

 more remarkable, as the innumerable holes had been 

 made within a fortnight, for before that time I saw the 

 bees everywhere sucking in the proper manner at the 

 mouths of the corolla. In an extensive flower-garden 

 some large beds of Salvia grahami, Stachys coccinea, 

 and Pentstemon argutus (?) had every flower per- 

 forated, and many scores were examined. I have seen 

 whole fields of red clover (Trifolium pratense) in the 

 same state. Dr. Ogle found that 90 per cent, of the 



