﻿106 
  Mr. 
  J. 
  W. 
  Douglas 
  on 
  the 
  

  

  leaf, 
  a 
  fact 
  first 
  observed, 
  or 
  at 
  least 
  made 
  known 
  at 
  one 
  of 
  our 
  

   meetings, 
  by 
  Mr. 
  Westwood. 
  Where 
  the 
  cocoons 
  of 
  other 
  species 
  

   are 
  placed 
  is 
  not 
  yet 
  known. 
  

  

  " 
  We 
  also 
  find 
  on 
  the 
  same 
  roses 
  and 
  on 
  the 
  dog 
  rose 
  blotch 
  

   miners 
  ; 
  indeed, 
  there 
  are 
  no 
  shrubs 
  on 
  which 
  these 
  miners 
  are 
  

   more 
  common. 
  The 
  membrane 
  of 
  the 
  upper 
  side 
  only 
  makes 
  a 
  

   little 
  protuberance 
  outwards. 
  We 
  also 
  find 
  on 
  the 
  holly, 
  nut, 
  

   oak, 
  &c. 
  great 
  places 
  mined 
  and 
  covered 
  by 
  the 
  epidermis, 
  which 
  

   forms 
  a 
  convexity 
  outside 
  the 
  leaf, 
  without 
  having 
  a 
  sensible 
  ridge. 
  

  

  "This 
  epidermis, 
  in 
  drying, 
  might 
  easily 
  become 
  more 
  stretched, 
  

   but 
  the 
  shortening 
  of 
  its 
  fibres 
  cannot 
  force 
  it 
  to 
  assume 
  a 
  convex 
  

   form; 
  it 
  is 
  by 
  spinning 
  one 
  or 
  several 
  very 
  fine 
  webs 
  that 
  the 
  

   miner 
  has 
  obliged 
  it 
  to 
  separate, 
  and 
  to 
  keep 
  apart 
  from 
  the 
  por- 
  

   tion 
  of 
  the 
  leaf 
  from 
  which 
  it 
  has 
  been 
  loosened. 
  These 
  webs 
  

   are, 
  however, 
  as 
  already 
  mentioned, 
  hardly 
  perceptible 
  but 
  by 
  the 
  

   effects 
  they 
  produce 
  ; 
  but 
  in 
  order 
  to 
  convince 
  myself 
  that 
  the 
  in- 
  

   sects 
  do 
  spin 
  them 
  in 
  places 
  where 
  they 
  may 
  be 
  necessary, 
  I 
  

   pierced 
  with 
  the 
  point 
  of 
  a 
  penknife 
  the 
  thin 
  membrane 
  that 
  was 
  

   above 
  the 
  mined 
  place 
  of 
  a 
  rose 
  leaf, 
  and 
  made 
  a 
  small 
  rent 
  which 
  

   allowed 
  me 
  to 
  see 
  the 
  insect 
  exposed. 
  When 
  I 
  wished 
  to 
  ex- 
  

   amine 
  the 
  same 
  gap 
  twenty-four 
  hours 
  afterwards, 
  I 
  found 
  the 
  

   edges 
  reunited 
  by 
  a 
  web 
  which 
  the 
  miner 
  had 
  spun 
  on 
  the 
  in- 
  

   terior 
  surface 
  of 
  the 
  torn 
  epidermis. 
  I 
  cut 
  in 
  the 
  same 
  way 
  the 
  

   membranes 
  which 
  covered 
  the 
  blotch 
  miners 
  of 
  the 
  apple, 
  and 
  

   they 
  behaved 
  in 
  the 
  same 
  manner 
  as 
  the 
  rose 
  miner. 
  

  

  " 
  We 
  may, 
  however, 
  assure 
  ourselves 
  without 
  this 
  experiment 
  that 
  

   the 
  miners 
  of 
  the 
  apple 
  carpet 
  with 
  web 
  the 
  epidermis 
  they 
  have 
  

   loosened; 
  if 
  we 
  open 
  their 
  small 
  abode 
  it 
  is 
  best 
  to 
  do 
  so 
  on 
  the 
  

   thick 
  side, 
  and 
  we 
  see 
  all 
  the 
  edges 
  of 
  the 
  fleshy 
  part, 
  which 
  is 
  

   joined 
  to 
  the 
  epidermis, 
  are 
  whitish, 
  though 
  at 
  a 
  short 
  distance 
  

   from 
  these 
  the 
  fleshy 
  part 
  is 
  quite 
  green. 
  The 
  web 
  which 
  is 
  

   spread 
  over 
  the 
  epidermis 
  goes 
  a 
  little 
  beyond 
  the 
  place 
  where 
  it 
  

   is 
  joined 
  thereto. 
  

  

  " 
  We 
  only 
  perceive 
  the 
  green 
  of 
  this 
  fleshy 
  part 
  through 
  a 
  white 
  

   veil 
  spread 
  over 
  it. 
  

  

  " 
  Besides 
  the 
  insects 
  which 
  form 
  a 
  ridge 
  on 
  the 
  portion 
  of 
  the 
  

   epidermis 
  of 
  the 
  oak 
  leaves 
  which 
  they 
  have 
  loosened, 
  there 
  are 
  

   caterpillars, 
  as 
  we 
  have 
  just 
  seen, 
  and 
  even 
  of 
  different 
  kinds, 
  

   which 
  mine 
  the 
  same 
  leaf, 
  and 
  which 
  only 
  cause 
  the 
  epidermis 
  of 
  

   the 
  mined 
  part 
  to 
  assume 
  a 
  sliglit 
  convexity. 
  If 
  we 
  observe 
  at 
  

   certain 
  times 
  the 
  portion 
  of 
  the 
  epidermis 
  which 
  has 
  been 
  raised 
  

   by 
  some 
  larvae, 
  it 
  seems 
  to 
  have 
  in 
  its 
  middle 
  a 
  circle 
  more 
  

   opaque 
  than 
  the 
  rest; 
  this 
  I 
  have 
  observed, 
  more 
  than 
  at 
  any 
  

   other 
  time, 
  towards 
  the 
  end 
  of 
  July. 
  If 
  we 
  raise 
  this 
  portion 
  of 
  

  

  