﻿108 
  Dr. 
  G. 
  C. 
  Crampton's 
  Notes 
  on 
  the 
  Ancestry 
  of 
  the 
  

  

  diverged 
  from 
  the 
  ancestral 
  Dipterous 
  stem 
  before 
  the 
  

   existing 
  forms 
  of 
  Diptera 
  had 
  become 
  so 
  extremely 
  special- 
  

   ised 
  as 
  we 
  now 
  find 
  them 
  to 
  be." 
  According 
  to 
  Packard 
  

   (I.e.) 
  Hahday 
  considered 
  the 
  fleas 
  as 
  " 
  a 
  group 
  of 
  Diptera 
  

   allied 
  to 
  the 
  MycetophiHdae 
  ";..." 
  those 
  who 
  regarded 
  

   them 
  (the 
  fleas) 
  as 
  Diptera 
  were 
  Roesel, 
  Oken, 
  Straus- 
  

   Duerckheim, 
  Burmeister, 
  Haliday, 
  Newman, 
  Walker, 
  von 
  

   Siebold, 
  with 
  many 
  German 
  entomologists, 
  and 
  J. 
  Wagner 
  

   (1889). 
  They 
  were 
  regarded 
  as 
  Hemiptera 
  by 
  Fabricius 
  

   and 
  by 
  Ilhger. 
  . 
  . 
  . 
  The 
  fleas 
  were 
  placed 
  by 
  MacLeay 
  

   and 
  by 
  Balbiani 
  between 
  the 
  Diptera 
  and 
  Hemiptera; 
  

   by 
  Leach 
  between 
  the 
  Hemiptera 
  and 
  Lepidoptera; 
  by 
  

   Duges 
  between 
  the 
  Hymenoptera 
  and 
  Diptera; 
  and 
  by 
  

   Brauer 
  they 
  are 
  given 
  a 
  position 
  between 
  the 
  Diptera 
  and 
  

   Coleoptera." 
  Brues, 
  1901 
  (American 
  Naturahst, 
  35, 
  p. 
  336), 
  

   discusses 
  the 
  relationship 
  of 
  fleas 
  to 
  Phoridae, 
  and 
  Dahl, 
  

   1897 
  (Zool. 
  Anz., 
  20, 
  p. 
  409), 
  describes 
  a 
  Phorid, 
  PuUci- 
  

   phora, 
  which 
  he 
  considers 
  annectant 
  between 
  the 
  Phorids 
  

   and 
  fleas, 
  although 
  WandoUeck, 
  1898 
  (Zool. 
  Anz. 
  and 
  Wiss. 
  

   Rundschau), 
  takes 
  exception 
  to 
  Dahl's 
  statements 
  on 
  the 
  

   subject. 
  

  

  The 
  Diptera 
  are 
  undoubtedly 
  as 
  closely 
  related 
  to 
  the 
  

   Mecoptera 
  as 
  to 
  any 
  other 
  order 
  of 
  insects, 
  and 
  the 
  Meco- 
  

   ptera 
  have 
  apparently 
  departed 
  as 
  httle 
  as 
  any 
  hving 
  

   forms 
  from 
  the 
  type 
  ancestral 
  to 
  the 
  Diptera, 
  so 
  that 
  the 
  

   Dipteron 
  hue 
  of 
  development 
  has 
  been 
  represented 
  in 
  

   the 
  diagram- 
  as 
  though 
  merging 
  with 
  that 
  of 
  the 
  Mecoptera, 
  

   as 
  we 
  trace 
  them 
  both 
  back 
  to 
  their 
  common 
  Neuroptera- 
  

   like 
  ancestors. 
  As 
  was 
  mentioned 
  in 
  previous 
  papers, 
  I 
  

   find 
  in 
  such 
  Neuroptera 
  as 
  Nemoptera, 
  many 
  features 
  

   suggesting 
  the 
  presence 
  of 
  tendencies 
  in 
  the 
  Neuropteron 
  

   stem 
  which 
  are 
  later 
  to 
  find 
  opportunity 
  for 
  fuller 
  ex- 
  

   pression 
  in 
  the 
  development 
  of 
  the 
  Dipteron 
  type 
  of 
  

   insects. 
  Among 
  these 
  may 
  be 
  mentioned 
  the 
  tendency 
  

   toward 
  the 
  formation 
  of 
  the 
  elongate 
  type 
  of 
  head 
  in 
  

   Nemoptera, 
  the 
  reduction 
  of 
  the 
  hind-wings 
  in 
  this 
  insect 
  

   (which 
  if 
  carried 
  a 
  httle 
  further 
  would 
  result 
  in 
  the 
  pro- 
  

   duction 
  of 
  a 
  halter-hke 
  structure), 
  and 
  the 
  character 
  of 
  

   the 
  genitaha 
  in 
  males 
  of 
  Nemoptera. 
  On 
  the 
  other 
  hand, 
  

   the 
  resemblance 
  between 
  the 
  lower 
  Diptera 
  such 
  as 
  the 
  

   Tipuloid 
  forms 
  and 
  the 
  Bittacus-^\iQ 
  representatives 
  of 
  the 
  

   Mecoptera 
  is 
  very 
  striking 
  and 
  extends 
  even 
  to 
  the 
  more 
  

   minute 
  details, 
  the 
  head 
  and 
  mouthparts, 
  thoracic 
  sclerites, 
  

   and 
  genitaha 
  being 
  very 
  similar 
  in 
  the 
  two 
  groups 
  — 
  and 
  

  

  