86 THE METHOD 'OF DARWIN. 



degree to which the inner and outer membranes 

 forming the tube or spur were separated from 

 each other, also at the delicate nature of the 

 inner membrane, . . . and, lastly, at the quan- 

 tity of fluid contained between the two mem- 

 branes." He found the space between the 

 membranes of other nectaries quite dry. He 

 then examined other forms that do secrete nec- 

 tar in the ordinary way, and found the mem- 

 branes closely united, instead of separated by 

 a space. "I was therefore led to conclude," he 

 said, " that insects penetrate the lax membrane 

 of the nectaries of the above named orchids and 

 suck the copious fluid between the two mem- 

 branes. This was a bold hypothesis, for at the 

 time no case was known of insects penetrating 

 with their proboscides even the laxest mem- 

 brane." He afterwards learned that at the 

 Cape of Good Hope moths and butterflies pene- 

 trate peaches and plums, and in Queensland, 

 Australia, a moth penetrates the rind of the 

 orange. These facts merely proved his antici- 

 pation less anomalous than it had seemed. 

 The bees which he saw visiting Orchis morio 

 kept their proboscides inserted in the nectaries 

 for some time. He opened several nectaries, 

 and found brown specks, due, as he believed, 

 to punctures made some time before. Herman 



