﻿The 
  main 
  results 
  of 
  the 
  above 
  investigations 
  

  

  on 
  the 
  h'fe-history 
  of 
  some 
  muscoidean 
  

  

  flies 
  parasitic 
  on 
  insects. 
  

  

  The 
  preceding 
  paper 
  contains 
  descriptions 
  of 
  the 
  meta- 
  

   morphosis 
  in 
  some 
  species 
  of 
  the 
  groups 
  Tachininæ 
  and 
  

   Dexiinæ, 
  together 
  with 
  information 
  on 
  the 
  biology 
  of 
  

   the 
  larvæ. 
  

  

  1. 
  The 
  larvæ. 
  

  

  All 
  the 
  larvæ 
  examined 
  pass 
  during 
  development 
  through 
  

   three 
  stages 
  for 
  which 
  there 
  can 
  be 
  established 
  general 
  

   characters, 
  based 
  on 
  the 
  pharyngeal 
  skeleton 
  and 
  the 
  

   spiracles. 
  

  

  First 
  stage. 
  The 
  pharyngeal 
  skeleton 
  terminates 
  in 
  

   front 
  in 
  a 
  single, 
  pointed, 
  median 
  tooth; 
  on 
  each 
  side 
  of 
  

   this 
  there 
  is 
  a 
  little 
  hook 
  which 
  is 
  not 
  connected 
  with 
  the 
  

   pharyngeal 
  skeleton 
  by 
  an 
  articulation. 
  (Figs. 
  11,35). 
  Poste- 
  

   riorly 
  the 
  pharyngeal 
  skeleton 
  is 
  divided 
  into 
  a 
  pair 
  of 
  

   upper 
  and 
  a 
  pair 
  of 
  lower 
  pharyngeal 
  piates. 
  There 
  is 
  an 
  

   arched, 
  quadratic 
  plate 
  below 
  the 
  anterior 
  part 
  of 
  the 
  

   pharyngeal 
  skeleton 
  with 
  which 
  the 
  plate 
  is 
  not 
  in 
  firm 
  

   connection. 
  Only 
  one 
  pair 
  of 
  spiracles 
  is 
  present, 
  situated 
  

   on 
  the 
  last 
  segment; 
  each 
  spiracle 
  terminates 
  in 
  two 
  knobs, 
  

   placed 
  near 
  together 
  (Fig. 
  12). 
  

  

  Second 
  stage. 
  The 
  anterior 
  median 
  tooth 
  of 
  the 
  

   pharyngeal 
  skeleton 
  has 
  disappeared, 
  and 
  the 
  skeleton 
  is 
  

  

  