﻿Diptera, 
  Hemiptera 
  and 
  Insects 
  related 
  to 
  Neuroptera. 
  103 
  

  

  Pediculidae 
  with 
  the 
  Hemiptera 
  {sensu 
  lato). 
  Since 
  

   the 
  Pedicuhdae 
  have 
  many 
  points 
  in 
  common 
  with 
  both 
  

   Mallophaga 
  and 
  Hemiptera 
  (with 
  the 
  Homoptera), 
  their 
  

   Une 
  of 
  descent 
  has 
  been 
  represented 
  in 
  the 
  diagram 
  as 
  

   though 
  intermediate 
  between 
  that 
  of 
  the 
  Mallophaga 
  

   (with 
  the 
  Psocidae) 
  and 
  the 
  Hemiptera 
  (with 
  the 
  

   Homoptera). 
  

  

  The 
  Hemiptera 
  and 
  Homoptera 
  are 
  extremely 
  closely 
  

   related, 
  and 
  are 
  usually 
  grouped 
  in 
  a 
  single 
  order; 
  but 
  

   there 
  are 
  very 
  good 
  grounds 
  for 
  considering 
  that 
  the 
  

   insects 
  so 
  classed 
  should 
  be 
  divided 
  into 
  at 
  least 
  two 
  

   orders 
  — 
  the 
  Hemiptera 
  {sensu 
  stricto) 
  and 
  the 
  Homoptera 
  

   — 
  although 
  the 
  further 
  division 
  of 
  the 
  Homoptera 
  into 
  

   other 
  orders 
  by 
  Handhrsch, 
  1909 
  (Die 
  Fossilen 
  Insekten), 
  

   is 
  doubtless 
  too 
  extreme. 
  

  

  In 
  discussing 
  a 
  paper 
  by 
  Osborn, 
  1894 
  (Proc. 
  Ent. 
  

   Soc, 
  Washington, 
  vol. 
  3, 
  p. 
  190), 
  on 
  the 
  phylogeny 
  of 
  the 
  

   Hemiptera, 
  Ashmead 
  suggests 
  that 
  the 
  " 
  Pediculidae 
  

   are 
  the 
  oldest 
  forms 
  representing 
  the 
  stem 
  from 
  which 
  

   sprang 
  the 
  Homoptera 
  in 
  one 
  direction 
  and 
  the 
  Hetero- 
  

   ptera 
  in 
  another." 
  Most 
  of 
  those 
  who 
  group 
  the 
  Pedi- 
  

   cuhdae 
  with 
  the 
  Hemiptera, 
  however, 
  regard 
  them 
  as 
  

   " 
  degenerate 
  " 
  Hemipteroid 
  insects. 
  Paul 
  Meyer, 
  1876, 
  

   who 
  derives 
  the 
  Hemiptera 
  (with 
  the 
  Homoptera), 
  together 
  

   with 
  the 
  Pedicuhdae 
  and 
  Mallophaga, 
  from 
  a 
  " 
  Proto- 
  

   hemipteron 
  " 
  stem 
  apparently 
  paved 
  the 
  way 
  for 
  the 
  

   modern 
  view 
  of 
  the 
  interrelationships 
  of 
  the 
  Hemiptera, 
  

   Pediculidae, 
  Mallophaga, 
  etc., 
  expressed 
  by 
  Enderlein, 
  

   1904 
  (Zool. 
  Anz., 
  Bd. 
  28, 
  p. 
  121), 
  and 
  particularly 
  by 
  

   Boernex, 
  1904 
  (Zool. 
  Anz., 
  Bd. 
  27, 
  p. 
  511), 
  who 
  groups 
  

   the 
  Psocidae^ 
  Mallophaga, 
  Pedicuhdae, 
  Thysanoptera 
  and 
  

   Hemiptera 
  (with 
  the 
  Homoptera) 
  in 
  a 
  section 
  which 
  he 
  

   calls 
  the 
  " 
  Acercaria." 
  Handhrsch, 
  1909 
  (I.e.), 
  however, 
  

   following 
  certain 
  earher 
  investigators, 
  is 
  more 
  impressed 
  

   with 
  the 
  Neuropteroid 
  affinities 
  of 
  the 
  Hemiptera 
  (and 
  

   Homoptera) 
  as 
  exhibited 
  by 
  such 
  fossil 
  forms 
  as 
  Eugereon 
  

   boeckingi 
  described 
  by 
  Dohrn, 
  1867 
  (Stett. 
  Ent. 
  Zeit., 
  Bd. 
  

   28, 
  p. 
  145), 
  although 
  Kirkaldy, 
  1910 
  (Proc. 
  Hawaiian 
  Ent. 
  

   Soc, 
  vol. 
  ii, 
  p. 
  117), 
  thinks 
  that 
  Eugereon 
  is 
  not 
  " 
  even 
  

   a 
  Hemipteroid 
  insect 
  " 
  but 
  is 
  "a 
  Neuropteroid 
  insect 
  

   of 
  a 
  kind 
  that 
  has 
  no 
  representatives 
  in 
  modern 
  times, 
  

   that 
  has 
  become 
  extinct, 
  forming 
  an 
  order 
  or 
  suborder 
  of 
  

   its 
  own." 
  In 
  several 
  papers 
  I 
  have 
  called 
  attention 
  to 
  

   the 
  Neuropteroid 
  character 
  of 
  the 
  thorax 
  of 
  such 
  lower 
  

  

  