Direct and Indirect Protection. 35 



same defensive appliance occurs sometimes on one part 

 of a plant, sometimes on another; is sometimes developed 

 on the stem, sometimes on the leaves, sometimes on 

 the perianth ; and that often plants, which having 

 regard. to other characters we should reckon as belong- 

 ing to the most different families, are yet provided with 

 identical means of protection. 



The defences against unwelcome guests may, accord- 

 ing to my views, be divided into those which directly 

 protect the flowers or some part of the same, and those 

 which, though they do not directly prevent entrance 

 into the flower, yet present an indirect hindrance. 

 These indirect methods of defence are again of two 

 kinds. In the one, at the time when the visit of the 

 insect would be prejudicial, the organ which attracts it 

 discontinues its function ; in the other, formations are 

 developed on the path by which the insect must 

 approach the flower, which themselves furnish a suffi- 

 ciency of dainty food, and ,so detain the visitor and 

 prevent its further advance. 



In the succeeding pages I shall follow the order 

 thus indicated. 



1. Protection from certain Animals h/ the Secretion in 

 the Flowers of Distasteful Sulstances. 



Any one who has bred butterflies, and for this pur- 

 pose has fed caterpillars, knows that many of these 

 latter eat the leaves of that plant which is their special 



