﻿aut. 
  1 
  AMERICAN 
  PLOIARIINAE 
  McATEE 
  AND 
  MALLOCH 
  3 
  

  

  swollen 
  at 
  base, 
  and 
  acute 
  at 
  tip, 
  and 
  distinctly 
  3-segmented. 
  The 
  

   thorax 
  is 
  variously 
  formed 
  and 
  the 
  wings 
  may 
  be 
  either 
  large, 
  re- 
  

   duced, 
  or 
  absent. 
  The 
  basal 
  abdominal 
  tergite 
  is 
  situated 
  on 
  the 
  

   posterior 
  part 
  of 
  thorax 
  and 
  the 
  basal 
  sternite 
  is 
  absent, 
  a 
  fact 
  that 
  

   should 
  be 
  borne 
  in 
  mind 
  in 
  counting 
  the 
  abdominal 
  segments. 
  The 
  

   male 
  hypopygium 
  opens 
  more 
  or 
  less 
  dorsally, 
  and 
  the 
  apical 
  tergite 
  

   sometimes 
  entirely 
  covers 
  the 
  orifice. 
  

  

  The 
  fore 
  wings 
  of 
  the 
  Ploiariinae 
  (as 
  also 
  those 
  of 
  some 
  other 
  

   Eeduviidae) 
  constitute 
  an 
  exception 
  to 
  a 
  commonly 
  accepted 
  cri- 
  

   terion 
  to 
  the 
  Heteroptera 
  in 
  that 
  they 
  are 
  of 
  uniform 
  texture 
  

   throughout. 
  The 
  venation 
  has 
  not 
  been 
  homologized 
  with 
  that 
  of 
  

   other 
  insects 
  and 
  the 
  names 
  applied 
  by 
  us 
  to 
  the 
  cells 
  and 
  veins 
  are 
  

   arbitrary 
  terms, 
  which 
  however, 
  are 
  clearly 
  defined 
  in 
  the 
  explana- 
  

   tion 
  of 
  plate 
  1. 
  

  

  The 
  fore 
  legs 
  of 
  Ploiariinae 
  are 
  adapted 
  for 
  capture 
  of 
  prey 
  by 
  

   closure 
  hinge-wise 
  of 
  the 
  fore 
  tibia 
  and 
  tarsus 
  against 
  the 
  lower 
  

   surface 
  of 
  the 
  fore 
  femur. 
  The 
  opposing 
  surfaces 
  of 
  the 
  front 
  fem- 
  

   ora 
  and 
  tibia 
  are 
  nearly 
  always 
  armed 
  with 
  spines 
  or 
  setulae, 
  the 
  

   arrangement 
  of 
  which 
  is 
  characteristic, 
  as 
  a 
  rule, 
  in 
  each 
  genus, 
  

   minor 
  variations 
  in 
  them 
  indicating 
  subgeneric 
  or 
  specific 
  groups. 
  

   The 
  fore 
  tibia 
  has 
  a 
  rather 
  conspicuous 
  transverse 
  slit 
  (figs. 
  13, 
  18, 
  

   136, 
  and 
  145) 
  on 
  the 
  anterior 
  surface 
  near 
  apex 
  which 
  is 
  surrounded 
  

   by 
  dense 
  pilosity. 
  The 
  fore 
  tarsi 
  present 
  a 
  range 
  of 
  differentiation 
  

   not 
  found 
  in 
  any 
  group 
  of 
  similarly 
  related 
  forms 
  known 
  to 
  us. 
  In 
  

   the 
  case 
  of 
  this 
  strictly 
  predaceous 
  subfamily, 
  it 
  is 
  natural 
  to 
  sup- 
  

   pose 
  that 
  evolution 
  has 
  been 
  in 
  the 
  direction 
  of 
  efficiency 
  in 
  the 
  most 
  

   important 
  raptorial 
  organs, 
  the 
  front 
  legs. 
  In 
  our 
  opinion, 
  the 
  fore 
  

   tarsus 
  in 
  its 
  most 
  generalized 
  form 
  consists 
  of 
  distinctly 
  separated 
  

   segments 
  the 
  terminal 
  one 
  with 
  two 
  equal 
  claws. 
  We 
  assume 
  the 
  

   course 
  of 
  evolution 
  to 
  be 
  from 
  that 
  condition 
  through 
  forms 
  with 
  

   poorly 
  defined, 
  heavily 
  chitinized 
  segments 
  with 
  one 
  large 
  and 
  one 
  

   small 
  claw 
  to 
  a 
  highly 
  specialized 
  stage 
  in 
  which 
  the 
  fore 
  tarsus 
  is 
  

   thorn-like, 
  the 
  joints 
  entirely 
  fused, 
  and 
  wholly 
  without 
  differenti- 
  

   ated 
  claw. 
  The 
  mid 
  and 
  hind 
  tarsi 
  are 
  invariably 
  3-segmented 
  and 
  

   being 
  used 
  in 
  the 
  normal 
  manner, 
  not 
  for 
  grasping 
  prey, 
  are 
  not 
  

   specialized. 
  

  

  IS 
  TRIBAL 
  DIVISION 
  OF 
  THE 
  PLOIARIINAE 
  ADVISABLE? 
  

  

  Attempts 
  have 
  been 
  made 
  to 
  define 
  tribes 
  of 
  Ploiariinae. 
  two 
  of 
  the 
  

   principal 
  efforts 
  along 
  this 
  line 
  being 
  by 
  Stal 
  1 
  and 
  by 
  Distant. 
  2 
  

   Put 
  in 
  the 
  form 
  of 
  indented 
  dichotomous 
  keys 
  these 
  schemes 
  are 
  

   herewith 
  appended. 
  

  

  1 
  Enum. 
  Hemip., 
  vol. 
  4, 
  1S74, 
  pp. 
  92-94. 
  

  

  2 
  Fauna 
  Brit. 
  India, 
  Rhynchota, 
  vol. 
  2, 
  1904, 
  pp. 
  201-216. 
  

  

  