﻿422 
  Dr. 
  H. 
  Eltringham 
  on 
  the 
  

  

  retain 
  it 
  for 
  the 
  present. 
  Is 
  this 
  term 
  to 
  be 
  apphed 
  to 
  

   any 
  modification 
  of 
  insect 
  scales 
  or 
  hairs 
  characteristic 
  

   of 
  the 
  male 
  insect, 
  or 
  is 
  it 
  to 
  be 
  confined 
  to 
  those 
  structures 
  

   that 
  have 
  a 
  direct 
  connection 
  with 
  glandular 
  tissue 
  of 
  

   a 
  sexual 
  character 
  ? 
  If 
  the 
  former, 
  the 
  word 
  becomes 
  

   almost 
  too 
  vague 
  to 
  be 
  useful, 
  if 
  the 
  latter, 
  then 
  the 
  brush 
  

   hairs 
  in 
  Hestia 
  are 
  androconia, 
  whilst 
  those 
  in 
  D. 
  chrysijypus 
  

   are 
  not, 
  and 
  so 
  before 
  we 
  can 
  use 
  the 
  term 
  at 
  all, 
  we 
  must 
  

   have 
  a 
  Imowledge 
  of 
  the 
  histology 
  and 
  perhaps 
  even 
  of 
  the 
  

   embryology 
  of 
  the 
  structures 
  to 
  which 
  we 
  refer. 
  

  

  It 
  would 
  seem, 
  then, 
  that 
  if 
  we 
  aim 
  at 
  greater 
  precision 
  

   in 
  terms 
  we 
  merely 
  arrive 
  at 
  the 
  position 
  of 
  a 
  person 
  who 
  

   cannot 
  describe 
  a 
  landscape 
  because 
  he 
  has 
  not 
  measured 
  

   the 
  elevations 
  to 
  see 
  whether 
  they 
  are 
  hills 
  or 
  mountains, 
  

   and 
  fears 
  to 
  mention 
  a 
  wood 
  till 
  he 
  has 
  identified 
  the 
  

   species 
  of 
  trees 
  it 
  contains. 
  

  

  In 
  describing 
  the 
  organs 
  in 
  these 
  small 
  Trichoptera 
  I 
  

   propose, 
  then, 
  to 
  use 
  the 
  word 
  hairs 
  when 
  referring 
  to 
  the 
  

   long, 
  fine 
  bristles 
  which 
  form 
  brushes 
  similar 
  in 
  form 
  to 
  the 
  

   brushes 
  described 
  in 
  the 
  Danainae. 
  In 
  several 
  species 
  

   there 
  are 
  structures 
  which, 
  though 
  of 
  varying 
  form, 
  resemble 
  

   more 
  or 
  less 
  closely 
  the 
  scent-scales 
  already 
  known 
  to 
  occur 
  

   in 
  many 
  Lepidoptera. 
  Though 
  the 
  word 
  is 
  unsatisfactory 
  

   I 
  shall 
  refer 
  to 
  them 
  as 
  androconia, 
  for 
  the 
  reason 
  already 
  

   stated. 
  

  

  Finally, 
  there 
  are 
  the 
  elongated 
  scales 
  or 
  hairs 
  found 
  so 
  

   plentifully 
  on 
  the 
  wings 
  and 
  body. 
  As 
  the 
  order 
  is 
  known 
  

   as 
  " 
  hairy 
  winged 
  " 
  as 
  distinguished 
  from 
  " 
  scale 
  winged 
  " 
  

   we 
  will 
  call 
  them 
  the 
  cuticle 
  hairs. 
  

  

  The 
  organs 
  to 
  be 
  described 
  are, 
  of 
  course, 
  only 
  found 
  in 
  

   the 
  male 
  sex. 
  

  

  Descriptive. 
  

  

  Hydroptila 
  sparsa 
  Curtis. 
  

  

  Four 
  eversible 
  tubercles 
  arise 
  from 
  a 
  membrane 
  lying 
  

   across 
  the 
  back 
  of 
  the 
  head, 
  such 
  tissue 
  forming 
  the 
  lightest 
  

   possible 
  protection 
  for 
  the 
  brain 
  situated 
  immediately 
  

   beneath 
  it. 
  Towards 
  the 
  upper 
  and 
  anterior 
  edge 
  of 
  this 
  

   membrane 
  there 
  is 
  on 
  its 
  underside 
  a 
  layer 
  of 
  moderately 
  

   large 
  cells 
  which 
  may 
  be 
  merely 
  hypodermal, 
  but 
  probably 
  

   also 
  have 
  a 
  glandular 
  function. 
  Arising 
  from 
  this 
  mem- 
  

   brane 
  on 
  its 
  upper 
  portion 
  and 
  on 
  either 
  side 
  of 
  the 
  centre 
  

   Une 
  is 
  found 
  a 
  small 
  tuft 
  of 
  very 
  remarkable 
  androconia 
  

  

  