92 THE FERTILISATION OF FLOWERS. [parr ut. 
another as soon as it is struck by the stamens whose bases it has 
touched, and it rarely thrusts its proboscis a second time into the 
same flower. When it plants its forelegs upon the flower, it 
usually causes the greater number of the stamens to close in upon 
the pistil. 
I have often seen humble-bees, on the other hand, thrust their 
proboscides again and again into the same flower. 
It is clear from the above that Sprengel is in error when he 
explains the flower of the barberry as adapted for self-fertilisation ; 
and this is proved most unequivocally by a closer examination of 
the movement of the anthers upon irritation. 
Before the flower opens the anthers stand on a level with the 
stigma; they are closely applied to the stigma in the bud, but in 
the opening flower they are bent as far backwards as the sur- 
rounding petals allow. As soon as the petals begin to diverge, 
the anthers dehisce, the lid flying up and remaining attached only 
to the extreme end of the connective, which is here at its broadest. 
The anther-lid carries with it almost all the pollen, and after rising 
to its full height it turns that side which bears the pollen inwards 
towards the middle of the flower. If the stamens are now touched 
at their bases and made to move inwards, the masses of pollen do 
not come on a level with the stigma, but stand above it; so that 
even those parts of the masses of pollen which do not touch the 
insect, excluding some little scattered particles, do not come in 
contact with the stigma: the insect’s head or proboscis, however, 
in being drawn back and rubbed against the masses of pollen 
gets dusted with pollen just in those parts which will come in 
contact with the stigma in other flowers. 7 
If insect-visits altogether fail, then, as the flowers wither, the 
masses of pollen come of themselves into contact with the stigma 
through the bending inwards of the anthers. I have observed this 
in specimens kept in my room, but I cannot say what results follow 
self-fertilisation at such a late period. 
Visitors: A. Diptera—(a) Syrphide : (1) Helophilus floreus, L., very ab. ; 
(2) H. pendulus, L. ; (3) Eristalis tenax, L., ab. ; (4) E. arbustorum, L. ; (5) 
E. nemorum, L.; (6) Rhingia rostrata, L., ab. ; (b) Muscidae: (7) Onesia 
floralis, R. D.; (8) O. sepulcralis, Mgn. ; (9) O. cognata, Mgn. ; (10) Musca 
domestica, L.; (11) M. corvina, F. B. Hymenoptera—(a) Apide: (12) 
Apis mellifica, L. §, ab.; (13) Bombus terrestris, L. 2 ; (14) B. pratorum, 
L. 9 ; (15) Andrena Trimmerana, K. 9; (16) A, helvola, L. ¢; (17) A. 
fulvicrus, K. ¢, ab.; (18) A. fulva, Schrk. 9, moderately ab.; (19) A. 
albicans, K. 9; (20) A. Smithella, K. 9; (21) Halictus rubicundus, Chr. ? , 
