ECOLOGY OF FLOWERS; POLLINATION 173 
206. Protection of Pollen from Unwelcome Visitors. — It 
is usually desirable for the flower to prevent the entrance 
of small creeping insects, such as ants, which carry little 
pollen and eat a relatively large amount of it. The means 
adopted to secure this result are many and curious. In 
some plants, as the common catchfly, there is a sticky 
Fic. 129. Bees visiting Flowers. 
At the left, a bumblebee on the flower of the dead nettle; below, a similar 
bee in the flower of the horse-chestnut; above, a honey-bee in the 
flower of a violet. 
ring about the peduncle, some distance below the flowers, 
and this forms an effectual barrier against ants and like 
insects. Very frequently the calyx tube is covered with 
hairs, which are sometimes sticky. 
Sometimes the recurved petals or divisions of the corolla 
stand in the way of creeping insects. In other cases the 
throat of the corolla is much narrowed or closed by hairs 
