50 PHYSIOLOGY OF THE EGGS. 
extremely large, in proportion to the size of the 
hody, as exemplified in the figure beneath : 
There can be little doubt that the silken web keeps 
the eggs in a proper temperature during winter. 
These cocoons are besides always under the shelter of 
some wall, or in the hollow of a tree. Silk is known 
to be an excellent non-conductor of electricity, and 
therefore must preserve the eggs in an equable 
temperature. The following is the appearance pre- 
sented by the eggs laid in the cocoon, from which 
the female has issued: 
I shall revert to this subject again, when treating 
of Moths, and give examples of many peculiarities 
in the different species, and of the manner in which 
they deposit their eggs. 
In reference to the degree of cold which the eggs 
of insects can endure, I shall give the ingenious ex- 
