﻿REVISION 
  OF 
  TRIBE 
  CERESINI 
  — 
  CALDWELL 
  507 
  

  

  Pronotum 
  greatly 
  elevated; 
  metopidium 
  perpendicular, 
  widening 
  

   to 
  prominent 
  rounded 
  suprahumerals, 
  the 
  sides 
  meeting 
  before 
  middle 
  

   of 
  body; 
  posterior 
  process 
  gradually 
  acuminate 
  apically, 
  strongly 
  

   declivent, 
  extending 
  beyond 
  the 
  abdominal 
  apex. 
  

  

  Lateral 
  valves 
  of 
  males 
  with 
  teeth 
  shorter 
  than 
  width 
  of 
  valves; 
  

   teeth 
  arising 
  just 
  dorsad 
  to 
  center 
  of 
  anterior 
  margins 
  of 
  valves. 
  

   Sternal 
  plate 
  with 
  small 
  apical 
  notch. 
  Styles 
  long, 
  S-shaped, 
  appear- 
  

   ing 
  caliperUke 
  in 
  ventral 
  aspect; 
  apices 
  flattened, 
  truncate, 
  minutely 
  

   serrate. 
  Aedeagus 
  with 
  posterior 
  arm 
  much 
  more 
  slender 
  than 
  

   anterior; 
  functional 
  orifice 
  subapical, 
  elongate-oval. 
  

  

  Description 
  based 
  on 
  male 
  neotype 
  from 
  Jefferson 
  City, 
  Mo., 
  June 
  

   30, 
  1940 
  (Adams). 
  

  

  Members 
  of 
  Tortistilus 
  are 
  known 
  to 
  occur 
  only 
  in 
  the 
  Nearctic 
  

   region, 
  and 
  as 
  far 
  as 
  known 
  their 
  life 
  cycles 
  approximate 
  those 
  of 
  

   Stictocephala 
  in 
  that 
  the 
  egg 
  stage 
  is 
  passed 
  upon 
  a 
  woody 
  host 
  and 
  

   the 
  immatures 
  develop 
  upon 
  herbaceous 
  plants. 
  Many 
  of 
  the 
  species 
  

   are 
  of 
  economic 
  importance 
  in 
  apple 
  culture; 
  inermis 
  was 
  reported 
  

   as 
  a 
  major 
  pest 
  in 
  the 
  Pacific 
  Northwest 
  by 
  Yothers, 
  1934. 
  

  

  Since 
  the 
  aedeagus 
  in 
  this 
  genus 
  is 
  the 
  same 
  as 
  that 
  in 
  Stictocephala 
  

   it 
  is 
  possible 
  that 
  it 
  should 
  not 
  be 
  considered 
  generically 
  distinct; 
  

   however, 
  the 
  styles 
  of 
  the 
  two 
  groups 
  are 
  very 
  dissimilar 
  and 
  in 
  general 
  

   the 
  thoracic 
  profiles 
  are 
  very 
  different, 
  so 
  the 
  two 
  groups 
  are 
  herein 
  

   considered 
  to 
  represent 
  two 
  distinct 
  genera. 
  

  

  The 
  inclusion 
  of 
  lateralis 
  (Funkhouser) 
  and 
  trilineatus 
  (Funkhouser) 
  

   in 
  Tortistilus 
  may 
  be 
  questioned 
  because 
  they 
  differ 
  from 
  other 
  species 
  

   in 
  this 
  genus 
  by 
  slight 
  differences 
  in 
  the 
  aedeagus, 
  styles, 
  teeth 
  on 
  the 
  

   lateral 
  valves, 
  pronotal 
  profile, 
  and 
  the 
  fact 
  that 
  they 
  both 
  occur 
  on 
  

   cypress. 
  "VVTiile 
  it 
  is 
  recognized 
  that 
  the 
  forms 
  on 
  cypress 
  represent 
  

   a 
  distinct 
  branch 
  of 
  Tortistilus 
  it 
  is 
  believed 
  that 
  this 
  branch 
  is 
  not 
  

   far 
  enough 
  removed 
  to 
  be 
  considered 
  as 
  generically 
  distinct. 
  

  

  T. 
  inermis, 
  collinus, 
  pacificus, 
  and 
  wickhami 
  comprise 
  a 
  difficult 
  but 
  

   very 
  interesting 
  group. 
  The 
  apices 
  of 
  the 
  styles 
  in 
  these 
  forms 
  aie 
  

   subject 
  to 
  considerable 
  variation 
  in 
  form 
  and 
  size; 
  however, 
  this 
  vari- 
  

   ation 
  has 
  a 
  limited 
  range 
  for 
  each 
  species 
  and 
  as 
  a 
  whole 
  the 
  apices 
  

   are 
  very 
  pertinent 
  for 
  specific 
  diagnosis. 
  

  

  The 
  variability 
  of 
  the 
  styles 
  in 
  inermis 
  received 
  comment 
  from 
  

   Lawson, 
  1922, 
  who 
  illustrated 
  (pi. 
  4, 
  figs. 
  1, 
  5, 
  8) 
  three 
  different 
  

   examples. 
  Throughout 
  the 
  species 
  it 
  seems 
  that 
  specimens 
  from 
  one 
  

   locality 
  differ 
  slightly 
  from 
  specimens 
  of 
  the 
  same 
  species 
  from 
  another 
  

   locality 
  with 
  these 
  differences 
  being 
  more 
  pronounced 
  in 
  material 
  

   from 
  mountainous 
  areas. 
  

  

  T. 
  minutus 
  is 
  characterized 
  by 
  the 
  low 
  pronotum 
  and 
  by 
  the 
  tooth- 
  

   like 
  projection 
  at 
  the 
  inner 
  apical 
  angle 
  of 
  the 
  styles. 
  T. 
  collinus 
  is 
  

   readily 
  separated 
  from 
  the 
  related 
  forms 
  by 
  the 
  greatly 
  suppressed 
  

   suprahumerals 
  and 
  by 
  the 
  styles 
  that 
  are 
  similar 
  in 
  form 
  but 
  larger 
  

  

  818288 
  49—3 
  

  

  