46 PHYSIOLOGY OF THE EGGS 
These eggs produced, when in the possession of Mr 
Rennie, in April 1830, a numerous brood of cater- 
pillars. 
As these eggs are laid in August, and destined 
to endure the storms of winter, the female seems to 
have some foresight of this, in forming so compact 
and appropriate a covering, constructed on principles 
equal to the best devised methods of human inge- 
nuity. It is the spring of the year before they are 
hatched, when the elm comes into leaf. 
The whole number of eggs laid by one female is 
frequently placed in a single group, and at other 
times in several smaller ones ; either considerably 
apart, on the same plant, or on others which are 
contiguous. ‘The parent insect seems to hold in view, 
in the latter case, the impropriety of ovipositing 
more in one situation than will supply the quantity 
of food sufficient to satisfy the wants of the excluded 
caterpillars. 
There is great diversity in the arrangement of 
the eggs after extrusion. Sometimes they are depo- 
sited in confused masses ; but in general, they are 
arranged in the most orderly and eyen systematic 
manner. The common Cabbage Butterfly, with 
various other insects, place their eggs upon one end, 
ranked close together in perfect order: by this 
