ANNULOSA. 541 



to repeat it again in another season. In other cases, the 

 female only survives, while, in many, death ensues, upon 

 the eggs being prepared and excluded. 



The apparatus with which some species are furnished, 

 to enable them to place their eggs in a proper situation, has 

 been denominated the ovipositor. It is a continuation of 

 the vulva, more or less strengthened by bony spiculae, ac- 

 cording to the nature of the substance it is destined to pe- 

 netrate. 



The period which elapses between the union of the sexes, 

 and the laying of the eggs, extends to days in some, and 

 even to months in others. The eggs themselves are either 

 excluded at once, or at particular intervals. They are de- 

 posited under one or other of the following conditions. In 

 the first, the egg, upon being deposited, is left to the influ- 

 ences of external circumstances, and the young, when hatch- 

 ed, to the resources of their own instinct. In the deposi- 

 tion of the egg, the wisest arrangements are made for the 

 welfare of the young. The mother attaches them, in ge- 

 neral, to those substances on which, upon being hatched, 

 they are destined to feed. The butter-fly attaches her eggs 

 to a leaf ; the flesh-fly deposits her*s upon carrion ; while 

 others insert them into the young of other insects. Not a 

 few females prepare a particular hole, in which they place 

 the egg, and lay up for the young a suitable provision when 

 they burst the shell. In the second, where the species 

 live in society, the eggs are deposited within the dwelling, 

 and the young are reared and fed by the mother's care. 

 In the females of the crustaceous animals, the eggs, after 

 exclusion, are collected under the tail, or upon the feet, 

 and retained until the young come forth. Some of the 

 spiders carry the eggs, and even young, for a time, in bags 

 upon their backs. 



