FLOWERS AND INSECTS 249 
adapted to the large moths, with long proboscides which 
can reach the bottom of the tube. As the moth thrusts 
its proboscis into the tube, its head is pressed against 
the sticky button on each side, so that when it flies away 
these buttons stick to its head and the pollen masses are 
torn out. When the next flower is visited these pollen 
masses are thrust against the stigmatic surface. 
(2) Consecutive maturity.—In these cases pollen and stig- 
ma of the same flower are not mature at the same time. 
This is a common method of preventing self-pollination, 
and it is evident that it is effective. When the pollen is 
being shed, the stigma is not ready to receive; or when the 
stigma is ready to receive, the pollen is not ready to be 
shed. 
When the flowers of the ordinary figwort first open, the 
style bearing the stigma at its tip is found protruding 
Fic. 244.—Protogynous flower of figwort: .1, first stage, with stigma receptive; 
B, section of A, showing stamens within the corolla; C, second stage, with 
stigma past and anthers in position for shedding.—After Gray. 
from the urn-like flower, while the four stamens are curved 
down into the tube, and are not ready to shed their pollen 
(Fig. 244, A and B). At some later time, the style bearing 
the stigma wilts, and the stamens straighten up and pro- 
trude from the tube (Fig. 244, C). In this way, first the 
