180 



HINTS ON THE ANCESTRY OF INSECTS. 



metamorphosis." We have seen that even in them the term 

 "complete" is a relative and not absolute expression, and that 

 the terms larva and pupa are convenient designations for states 

 varying in duration, and assumed to fulfil certain ends of exis- 

 tence, and even then dependent on length of seasons, variation 

 in climate, and even on the locality. When we descend to the 

 insects with an "incomplete" metamorphosis, as in the May fly, 



206. Semi-pupa. 



207. Advanced Semi-pupa. 208. Pupa. 



EARLY STAGES OF THE HUMBLE BEE. 



we find that, as in the case of Chloeon, Sir John Lubbock has 

 described twenty-one stages of existence, and let him who can 

 say where the larval ends and the pupal or imaginal stages 

 begin. So in a stronger sense with the grasshopper and cock- 

 roach. The adult state in these insects is attained after a 

 number of moults of the skin, during each of which the insect 

 gradually draws nearer to the final winged form. But even the 



