exlii Proceedings of the Asiatic Society of Bengal. [N.S., XV, 
I have taken the case of a plant because it is relatively 
simple, but you will readily see that we could construct similar 
=: 
INTENSITY 
DISTANCE 
PiG.o. 
them from a distance by their smell. 
This curve shows his power of range, or mobility, at differ- 
ent stages. (Fig. 4.) 
Bodity Range 
Ecc Laava Pura Imaco 
Fie. 4. 
The immobile egg, hatching into a grub which we will 
suppose to burrow in the soil and have a limited range; then 
the immobile pupa, from which emerges the winged beetle with 
considerable range of movement. 
So far we have treated the beetle like the plant, but on 
the sensory plane it is obvious that we are not practically 
interested in the attractiveness of the beetle, since this doesn’t 
affect his oe ee _ the plant. What we want to know is 
something about his susceptibility to the plant’s attractions, 
the delicacy of his perception of the smell of the flower. 
