﻿391 
  

  

  X. 
  A 
  new 
  Hydroptila. 
  By 
  Martin 
  E. 
  Mosely, 
  F.E.S. 
  

  

  [Read 
  October 
  15th, 
  1919.] 
  

  

  Plate 
  XVIL 
  

  

  Hydroptila 
  simulans 
  n. 
  sp. 
  

  

  A 
  year 
  or 
  two 
  ago, 
  when 
  collecting 
  Hydroptilidae 
  in 
  the 
  

   neighbourhood 
  of 
  the 
  river 
  Test, 
  Hampshire, 
  I 
  found, 
  one 
  

   autumn, 
  amongst 
  a 
  large 
  number 
  of 
  Hydroptila 
  sparsa 
  Curt., 
  

   seven 
  male 
  examples 
  which, 
  though 
  similar 
  in 
  general 
  

   appearance 
  to 
  this 
  species, 
  showed 
  considerable 
  difference 
  

   in 
  the 
  shape 
  of 
  the 
  inferior 
  appendages 
  and 
  a 
  modification 
  

   in 
  the 
  shape 
  of 
  the 
  dorsal 
  plate. 
  Since 
  then, 
  some 
  forty 
  

   or 
  fifty 
  examples 
  have 
  turned 
  up 
  from 
  the 
  Test 
  district, 
  

   and 
  one 
  from 
  the 
  River 
  Dove 
  near 
  Ashbourne. 
  

  

  The 
  species 
  appears 
  to 
  be 
  plentiful 
  on 
  the 
  River 
  Colne, 
  

   in 
  the 
  neighbourhood 
  of 
  Uxbridge, 
  Middlesex. 
  

  

  In 
  the 
  accompanying 
  notes 
  on 
  scent-organs 
  in 
  Hydroptila 
  

   it 
  will 
  be 
  seen 
  that 
  in 
  H. 
  simulans 
  the 
  form 
  of 
  this 
  organ 
  

   would 
  alone 
  warrant 
  its 
  separation 
  from 
  H. 
  sparsa. 
  

  

  The 
  specimens 
  were 
  collected 
  in 
  fluid 
  and 
  then 
  mounted 
  

   in 
  Canada 
  balsam 
  : 
  I 
  am 
  consequently 
  precluded 
  from 
  

   describing 
  the 
  living 
  insect. 
  

  

  The 
  drawings 
  were 
  made 
  from 
  the 
  preparations, 
  the 
  

   dorsal, 
  ventral 
  and 
  lateral 
  figures 
  being 
  from 
  three 
  

   different 
  specimens. 
  

  

  Description 
  of 
  the 
  (^. 
  

  

  Expanse, 
  5|-6| 
  mm. 
  ; 
  abdomen, 
  green 
  or 
  brown. 
  

  

  Antennae 
  about 
  31-jointed 
  in 
  the 
  male, 
  the 
  head 
  fur- 
  

   nished 
  with 
  two 
  large 
  bi 
  valvular 
  lobes. 
  

  

  The 
  scent-organs, 
  which 
  are 
  everted 
  from 
  beneath 
  the 
  

   lobes, 
  take 
  the 
  form 
  of 
  two 
  tubular 
  filaments 
  clothed 
  with 
  

   yellow 
  hairs. 
  When 
  partly 
  everted 
  the 
  hairs 
  are 
  gathered 
  

   together 
  into 
  a 
  dense 
  golden 
  pencil 
  or 
  brush. 
  

  

  The 
  dorsal 
  plate 
  is 
  rather 
  deeply 
  excised 
  and 
  somewhat 
  

   similar 
  in 
  form 
  to 
  that 
  of 
  //. 
  sparsa, 
  but 
  the 
  excision 
  begins 
  

   at 
  the 
  extreme 
  angle 
  of 
  the 
  plate, 
  whereas 
  in 
  H. 
  sparsa 
  the 
  

   hind 
  margin 
  is 
  really 
  produced 
  from 
  the 
  hind 
  angle 
  and 
  

   then 
  abruptly 
  excised. 
  Towards 
  the 
  base 
  of 
  the 
  plate 
  are 
  

  

  TRANS, 
  ENT. 
  SOC. 
  LOND. 
  1919. 
  — 
  PARTS 
  III, 
  IV. 
  (deC.) 
  

  

  