﻿26 
  Eev. 
  T. 
  A. 
  Marshall's 
  Monofjraph 
  of 
  

  

  red, 
  and 
  hence 
  I 
  am 
  inclined 
  to 
  refer 
  them 
  to 
  the 
  present 
  

   species, 
  rather 
  than 
  to 
  0. 
  clarus. 
  

  

  3. 
  Opius 
  tacitus, 
  Hal. 
  

  

  O. 
  tacitus, 
  Hal., 
  Ent. 
  Mag., 
  iv., 
  207, 
  S 
  . 
  

  

  Black 
  ; 
  base 
  of 
  the 
  2d 
  abdominal 
  segment 
  rufous. 
  Face 
  sub- 
  

   carinated 
  ; 
  clypeus 
  reaching 
  the 
  mandibles 
  ; 
  both 
  testaceous. 
  

   Antennae 
  about 
  one-half 
  longer 
  than 
  the 
  body, 
  30-jointed, 
  broadly 
  

   rufo-testaceous 
  towards 
  the 
  base. 
  Mesothoracic 
  sutures 
  effaced. 
  

   No 
  punctiform 
  impression 
  before 
  the 
  scutellum. 
  Furrow 
  of 
  the 
  

   mesopleurse 
  impunctate. 
  Metathorax 
  rugulose. 
  Wings 
  hyaline 
  ; 
  

   squamula 
  testaceous 
  ; 
  nervures 
  fuscous 
  ; 
  stigma 
  fusco-testaceous, 
  

   linear-lanceolate 
  ; 
  2d 
  cubital 
  areolet 
  attenuated 
  outwards 
  ; 
  recur- 
  

   rent 
  nervure 
  evected. 
  Pobrachial 
  transverse 
  nervure 
  of 
  the 
  hind 
  

   wings 
  inchoate. 
  Legs 
  testaceous. 
  First 
  abdominal 
  segment 
  rugu- 
  

   lose. 
  Length, 
  1 
  line. 
  

  

  ? 
  Var. 
  1, 
  ? 
  . 
  Smaller 
  ; 
  base 
  of 
  antennae 
  fuscous, 
  only 
  the 
  scape 
  

   testaceous. 
  Stigma 
  narrower. 
  Legs 
  very 
  pale 
  testaceous. 
  Second 
  

   abdominal 
  segment 
  fuscous 
  ; 
  terebra 
  briefly 
  exserted. 
  Length, 
  

   f 
  line. 
  

  

  Originally 
  mixed 
  up 
  by 
  Haliday 
  with 
  rictus 
  or 
  spretus 
  

   (spp. 
  6, 
  7) 
  ; 
  from 
  the 
  latter 
  it 
  differs 
  in 
  having 
  the 
  joints 
  

   of 
  the 
  antennae 
  longer, 
  and 
  the 
  2d 
  cubital 
  areolet 
  shorter. 
  

   Compare 
  Bracon 
  circulator 
  and 
  orhiculator, 
  Nees, 
  Mon., 
  

   i., 
  54, 
  55, 
  the 
  descriptions 
  of 
  which 
  apply 
  equally 
  to 
  

   several 
  species 
  of 
  Opius. 
  I 
  have 
  not 
  seen 
  tacitus^ 
  

   which, 
  according 
  to 
  Haliday, 
  is 
  very 
  rare 
  in 
  North 
  

   Ireland 
  ; 
  a 
  single 
  specimen 
  was 
  taken 
  by 
  Walker 
  in 
  the 
  

   London 
  district. 
  

  

  9. 
  Opius 
  exilis, 
  Hal. 
  

   0. 
  exilis, 
  Hal., 
  Ent. 
  Mag., 
  iv., 
  208, 
  ? 
  . 
  

  

  Similar 
  to 
  0. 
  tacitus 
  (sp. 
  8) 
  and 
  0. 
  parvulus 
  (sp. 
  23). 
  Black; 
  

   2d 
  abdominal 
  segment 
  rufo-piceous. 
  Mouth 
  testaceous 
  ; 
  clypeus 
  

   reaching 
  the 
  mandibles. 
  Antennae 
  hardly 
  longer 
  than 
  the 
  body, 
  

   26-jointed 
  ; 
  scape 
  testaceous. 
  Mesothoracic 
  siitin-es 
  effaced. 
  No 
  

   punctiform 
  impression 
  before 
  the 
  scutellum. 
  Mesopleurte 
  with 
  an 
  

   impunctate 
  furrow. 
  Metathorax 
  shining 
  only 
  in 
  the 
  middle 
  of 
  the 
  

   base. 
  Second 
  cubital 
  areolet 
  short, 
  attenuated 
  outwards, 
  its 
  upper 
  

   side 
  scarcely 
  longer 
  than 
  the 
  inner; 
  recurrent 
  nervure 
  evected. 
  

   Legs 
  testaceous, 
  base 
  of 
  hind 
  coxae, 
  and 
  apex 
  of 
  all 
  the 
  tarsi, 
  

   fuscous. 
  Male 
  unknown. 
  Length, 
  \ 
  line. 
  

  

  