176 VANDEiE. Chap. VL 



of the pollen-mass glued to its back. The insect then 

 generally gets through the passage, and comes out 

 with this peculiar appendage, to return nearly imme- 

 diately to its feast, when it is generally precipitated a 

 second time into the bucket, passing out through the 

 same opening, and so inserting the pollen-masses into 

 the stigma while it forces its way out, and thereby im- 

 pregnating either the same or some other flower. I 

 have often seen this ; and sometimes there are so many 

 of these humble-bees assembled that there is a continual 

 procession of them through the passage specified," 



There cannot be the least doubt that the fertilisation 



of the flower absolutely depends on insects crawling 



out through the passage formed by the extremity of 



the febAHum and the over-arching column. If the 



^ ^^<ge distal'.portion of thelabellum or bucket had been 



"v> d^^:fli^-bees could easily have escaped by flying away* 



iT" '^^i^i!& we must believe that the fluid is secreted by 



>lf(i^affpBndages in such extraordinary quantity and is 



^feblls-cted iii the bucket, not as a palatable attraction 



for the bees, as these are known to gnaw the labellum, 



but for the sake of whetting their wings, and thus 



compelling them to crawl out through the passage. 



I have now described, perhaps in too much detail, 

 a few of the many contrivances by which the Vandea^ 

 are fertilised. The relative position and shape of the 

 parts — friction, viscidity, elastic and hygrometric move- 

 ments, all nicely related to one another — come into 

 play. But all these appliances are subordinate to the 

 aid of insects. Without their aid, not a plant belong- 

 ing to this tribe, in the species of the twenty-nine 

 genera examined by me, would set a seed. It is also 

 -certain in a majority of the cases, that insects withdraw 

 the poUinia only when istreating from the flower, and 



