Pliylctic Parallelism in Mctamorphic Species. 495 



process designated " convergence " by Oscar 

 Schmidt, /. e. upon the adaptation of heterogeneous 

 animal forms to similar conditions of life. By 

 adaptation to a life within a mass of fluid nutri- 

 ment, the caterpillar-formed larvae of the Hyme- 

 noptera and the 7"(/Wtf-like larvae of the Diptera 

 have acquired a similar external appearance, and 

 many similarities in internal structure, or, in brief, 

 have attained to a considerable degree of form- 

 relationship, which would certainly have tended 

 to conceal the wide divergence in blood-relation- 

 ship did not the embryological forms on the one 

 side and the imagines on the other provide us 

 with an explanation. 



It is certainly of great interest that in another 

 order of insects the Coleoptera grub-formed 

 larvae occur quite irregularly, and their origin can 

 be here traced to precisely the same conditions of 

 life as those which have produced the grubs of 

 bees. I refer to the honey-devouring larvae of 

 the MelvicUe (Melee, Sitaris, Cantharis], The 

 case is the more instructive, inasmuch that the 

 six-legged larval form is not yet relegated to the 

 development within the egg, but is retained in the 

 first larval stage. In the second larval stage the 

 maggot-form is first assumed, although this is cer- 

 tainly not so well pronounced as in the Diptera 

 or Hymenoptera, as neither the head nor the 

 thoracic legs are so completely suppressed as in 

 these orders. Nevertheless, these p;irts have 



