﻿496 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  vol.98 
  

  

  direct 
  influence 
  on 
  the 
  morphology 
  of 
  other 
  organs 
  or 
  structures 
  

   involved 
  in 
  copulation. 
  It 
  is 
  probable 
  that 
  as 
  the 
  styles 
  became 
  

   less 
  efficient 
  for 
  clasping 
  their 
  function 
  was 
  assumed 
  in 
  part 
  or 
  in 
  full 
  

   by 
  some 
  other 
  organs 
  or 
  structures 
  with 
  a 
  resulting 
  modification 
  of 
  

   these 
  parts, 
  or 
  it 
  may 
  be 
  possible 
  that 
  other 
  aids 
  to 
  clasping 
  arose 
  first 
  

   and 
  then 
  the 
  styles 
  became 
  less 
  efficient 
  or 
  modified. 
  Teeth 
  on 
  the 
  

   lateral 
  valves, 
  and 
  the 
  spines 
  or 
  processes 
  and 
  other 
  modifications 
  of 
  

   the 
  aedeagus, 
  are 
  interpreted 
  as 
  functioning 
  as 
  clasping 
  structures. 
  

   The 
  evidence 
  supporting 
  the 
  aforementioned 
  theories 
  may 
  be 
  observed 
  

   in 
  the 
  generic 
  series 
  of 
  Ceresini 
  where 
  the 
  arbitrarily 
  generalized 
  style 
  

   unrolls, 
  becomes 
  flattened, 
  shrinks 
  in 
  size, 
  and 
  then 
  vanishes 
  as 
  the 
  

   associated 
  structures 
  have 
  become 
  adapted 
  for 
  clasping. 
  Since 
  this 
  

   specialized 
  condition 
  has 
  not 
  been 
  observed 
  in 
  other 
  genera 
  of 
  Nearctic 
  

   Membracidae 
  it 
  is 
  believed 
  that 
  the 
  Ceresini, 
  especially 
  those 
  with 
  

   the 
  veins 
  of 
  the 
  corium 
  united 
  at 
  the 
  base, 
  form 
  a 
  distinct 
  and 
  adven- 
  

   titious 
  branch 
  of 
  the 
  Membracidae. 
  It 
  is 
  not 
  known 
  just 
  where 
  the 
  

   specialization 
  of 
  the 
  genitalia 
  begins 
  in 
  this 
  group 
  nor 
  is 
  it 
  known 
  

   whether 
  it 
  is 
  of 
  singular 
  or 
  multiple 
  origin; 
  however, 
  the 
  more 
  gen- 
  

   eralized 
  type 
  of 
  genitalia 
  occurs 
  in 
  Parantonae, 
  Micrutalis, 
  and 
  

   Acutalis. 
  Parantonae 
  is 
  perhaps 
  more 
  closely 
  related 
  to 
  the 
  Neo- 
  

   tropical 
  genera 
  Poppea 
  Sthl 
  and 
  Antonae 
  St§,l 
  than 
  to 
  any 
  Nearctic 
  

   genera 
  although 
  it 
  may 
  be 
  distantly 
  related 
  to 
  Acutalis. 
  Micrutalis 
  

   superficially 
  resembles 
  Acutalis, 
  but 
  the 
  styles 
  and 
  aedeagi 
  of 
  the 
  

   two 
  are 
  not 
  similar 
  and 
  the 
  relationship 
  cannot 
  be 
  very 
  close. 
  I 
  

   believe 
  that 
  Micrutalis 
  is 
  more 
  closely 
  related 
  to 
  the 
  Neotropical 
  

   genus 
  Brachytalis 
  Metcalf 
  and 
  Bruner, 
  which 
  in 
  its 
  present 
  concept 
  

   includes 
  some 
  species 
  with 
  minute 
  teeth 
  on 
  the 
  lateral 
  valves. 
  Some 
  

   species 
  of 
  Melusina 
  Stkl 
  and 
  Centrogonia 
  StM, 
  both 
  Neotropical, 
  

   have 
  teeth 
  on 
  the 
  lateral 
  valves 
  and 
  the 
  genera 
  are 
  distantly 
  related 
  to 
  

   Stictocephala 
  and 
  to 
  Ceresa, 
  a 
  genus 
  restricted 
  to 
  the 
  Neotropics. 
  

   Stictocephala 
  and 
  Tortistilis 
  both 
  have 
  similar 
  aedeagi 
  but 
  are 
  differen- 
  

   tiated 
  by 
  the 
  styles 
  which 
  are 
  apically 
  acute 
  in 
  the 
  former 
  and 
  apically 
  

   truncate 
  or 
  convergent 
  in 
  the 
  latter. 
  Anisostylus 
  seems 
  to 
  be 
  an 
  

   isolated 
  group 
  suggestive 
  of 
  Tortistilus 
  but 
  is 
  probably 
  more 
  closely 
  

   related 
  to 
  Spissistilus. 
  Spissistilv^ 
  may 
  well 
  be 
  the 
  progenitor 
  of 
  

   Vestistilus, 
  Stictolobus, 
  and 
  Trichaetipyga, 
  as 
  here 
  the 
  styles 
  have 
  

   definitely 
  begun 
  to 
  shorten 
  and 
  in 
  the 
  last 
  three 
  genera 
  the 
  styles 
  are 
  

   more 
  or 
  less 
  vestigial. 
  Vestistilus 
  is 
  probably 
  more 
  closely 
  related 
  to 
  

   Spissistilus 
  than 
  the 
  other 
  genera 
  since 
  the 
  aedeagus 
  is 
  not 
  too 
  dis- 
  

   similar 
  while 
  Trichaetipyga 
  is 
  probably 
  further 
  removed 
  because 
  the 
  

   aedeagus 
  in 
  this 
  genus 
  is 
  highly 
  modified. 
  Stictolobus 
  seems 
  to 
  be 
  a 
  

   separate 
  offshoot 
  from 
  Spissistilus 
  not 
  very 
  closely 
  related 
  to 
  

   Vestistilus 
  or 
  Trichaetipyga. 
  

  

  