——— > cscs 
ATTRACTION OF FLOWERS FOR INSECTS. 273 
5. 
In the next series, Prof. Plateau repeated the well-known 
observations of Darwin on Lobelia, with results somewhat dif- 
ferent from those of our great naturalist, but yet, I submit, 
pointing to the same conclusion. 
Darwin’s statement * was, * That the coloured corolla is the 
chief guide cannot be doubted. On a fine day, when Hive-bees 
were incessantly visiting the little blue flowers of Lobelia erinus, 
I cut off the petals of some, aud only the lower striped petals 
of others, and these flowers were not once ayain sucked by the 
Bees, although some aetually erawled over them. The removal 
of the two little upper petals alone made no difference in their 
visits." 
Plateau experimented as follows t :—‘ Deux pots de Lobelia 
sensiblement identiques, portant l'un et l'autre de trente à 
quarante fleurs, sont placés en plein air, à une bonne exposition 
(sud) et a 50 centimétres l'un de l'autre. 
“On les a posés chacun sur une planchette terminant un piquet, 
de maniére qu'ils dépassent d'une vingtaine de centimétres les 
plantes basses avoisinantes." 
The corollas were removed from the flowers in one of the pots, 
and the result was that 33 insects visited the intact flowers, aud 
25 those which were mutilated. Here, in the first place, the 
experiment was not continued long enough. In the second, they 
were only 50 centimetres apart, and insects which had visited 
the first pot would naturally proceed to the second. 
The difference in numbers was marked ; and, indeed, just what 
I should have expected under the circumstances. 
6. 
His next series of experiments were on Mnothera biennis. 
He removed all the corollas t, and *l'Abeille qui visite la plante 
Vole dans tous les sens, vers les fleurs fanées, vers les boutons, 
méme sur les pétales tombés à terre qu'elle examine assez atten- 
tivement en se promenant dessus ; cependant elle ne se pose pour 
butiner que sur les Jleurs mutilées privées de corolle." 
It will be noticed that the Bee visited the buds, the faded 
flowers, and even the petals on the ground, evidently attracted 
* ; . ,. 
The Effects of Cross- and Self-Fertilization in the Vegetable Kingdom’ : 
London, 1876, y, 420, 
t Bull. Acad. Bruxelles, Sér, IIL. xxx. (1895) p. 510. 
1 L.c. p. 516, 
