44 PHYSIOLOGY OF THE EGGS 



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 ingenuity. 

 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 remote from each 

 other, 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 even systematic 

 manner. The common Cabbage Butterfly, with 

 various other insects, place their eggs upon one end, 

 ranked close together in perfect order : by this 

 arrangement the larvae, which on hatching emanate 

 from the upper end, cannot disturb the adjoining 

 eggs. The eggs of many Papilios are formed so that 

 they are intended to be placed in this position. For 

 example, those of the Puss Moth ( Centra vinula) 

 have the case of a gummed transparent substance, 

 while the rest is cinereous and opaque. The Emperor 

 Moth lays eggs, by which the caterpillar can make 



