THE DIPT ERA. 



407 



The Bee Louse or Tick may be compared to a spider fly, and 

 is about two-thirds of a hue long. It is pupiparous, Hke the 

 sheep tick, and the very day it is hatched it sheds its skin and 

 changes to an oval pupa of a dark brown colour. Packard states 

 that its habits resemble those of the flea, and that it is evidently a 

 connecting link between the flea and the two-winged flies. Like 

 the former, it lives and brings forth its young on the body of its 

 victim or host, and draws its food by plunging its stout beak into 

 the skin of the bee ; and sometimes one of these industrious insects 

 may be seen to be weighed down by as many as a hundred of 

 these bloodthirsty creatures. 



The varieties of metamorphosis in the Dipiera are thus very 

 considerable, and it must strike every observer that the most 

 decided transformations are those of the parasitic flies. This is 

 one of the proofs that the metamorphosis has been gradually 

 added to the evolution of the insect, and that it is preservative of 

 the species. 



