54 PHYSIOLOGY OF THE EGGS 



with a central cavity above and below, and have their 

 circumference crossed with wrinkles, corresponding 

 with the rings of the enclosed embryo. There are 

 others which are figured all over. In the butterfly 

 Hipparchia JEgeria, all the surface is covered with 

 hexagonal reticulations, as under : 



In the new and restricted genus Vanessa of the 

 French authors, w r e find two species of butterflies, 

 which differ but little in their forms, the chief dis- 

 tinction being that the one is much larger than the 

 other : yet the eggs are so dissimilar, that they would 

 indicate insects of a totally different form. Those of 

 the small Tortoise-shell Butterfly are of a cylindrical 

 shape, with eight prominent ribs, as under : 



While the eggs of the large Tortoise-shell Butterfly 



