CHAPTER VII 



GROWTH AND TRANSFORMATION 



In the previous chapter we have discussed the behaviour of 

 the germ-cells in maturation and fertilisation, and the power 

 of determination exercised by their germinal constitution on 

 the nature of the insect that may be developed from either 

 the fertilised or the virgin egg. It is well known that 

 between such an egg and the adult of the next generation 

 there intervenes a longer or shorter process of growth and 

 change of form. Some of the more important features of 

 this process must now be described and discussed. In 

 tracing the complete life-history of an insect from egg to 

 adult it is convenient to discriminate first of all between 

 the embryonic development that goes on within the egg- 

 shell up to the appearance of the young insect in the outer 

 world, and the post-embryonic development which occurs 

 after hatching and brings about the growth of the newborn 

 or newly hatched creature into the mature insect capable 

 of reproduction. 



As the second of these periods of development is a 

 markedly characteristic feature of insect life, it will be 

 considered in greater detail than the embryonic growth 

 which is common, in some form, to animals generally. 

 Yet the development of an insect embryo presents many 

 features of interest which must not be altogether neglected 

 in our survey of the subject. 



Reference has already been made to the relatively large 

 size of an insect's egg^ and the amount of food-yolk that is 



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