Pinks and Chickweed 107 
What is the purpose of the bladder-like calyx it is 
not easy to see; but an enemy of the plant makes 
use of it for his own protection, and unless it served 
some useful purpose to the plant, we should expect 
natural selection to do away with it. There are 
several species of Noctuid moths whose caterpillars 
feed on the unripe seeds of py 
certain members of the Pink ne \ 
family. One of these is called } 
the Tawny Shears (Dianthecia 
carpophaga), and another the 
Campion-moth (D. cucubailz). 
Their eggs are laid in the flowers 
in June, and about a week later 
the young caterpillar is hatched, 
bores into the growing seed- 
vessel, and begins to eat the un- 
ripe seeds. Having demolished 
these, it passes to an older 
capsule, and if too large to enter 
it, hes coiled in a ring round it 
within the calyx-bladder, so that 
this becomes for a time a pro- 
tection for the plant’s chief 
enemy—one that partially prevents the plant from 
perpetuating its kind. Finally the caterpillar gets 
too large to be thus accommodated, and it is com- 
pelled to hide at the roots of the plant during the 
day to escape bird-enemies. In the evening it crawls 
up to the seed-vessels again, where it may be found 
with its head and fore-parts hidden in the calyx, and 
its hinder part exposed. 
There is another plant, called the Sea Campion 
Sea Campion 
