﻿16 
  

  

  arc 
  of 
  no 
  extraordinary 
  interest 
  to 
  the 
  fruit 
  grower, 
  none 
  of 
  them 
  

   being 
  either 
  as 
  abundant 
  or 
  as 
  destructive 
  when 
  present 
  as 
  the 
  com- 
  

   monest 
  of 
  the 
  native 
  orchard 
  scales, 
  the 
  so-caRed 
  scurfy 
  scale 
  of 
  the 
  

   apple. 
  Chionaspis 
  furfurus. 
  It 
  often 
  becomes, 
  conse([uently, 
  a 
  

   matter 
  of 
  special 
  interest 
  and 
  importance 
  that 
  this 
  most 
  destructive 
  

   San 
  Jos^ 
  scale 
  should 
  be 
  positively 
  distinguished 
  from 
  the 
  others, 
  

   and 
  to 
  this 
  end 
  I 
  have 
  had 
  prepared 
  by 
  my 
  Assistant, 
  Mr. 
  C. 
  A. 
  Hart, 
  

   the 
  following^ 
  comparison 
  of 
  characters, 
  both 
  superficial 
  and 
  minute. 
  

  

  Besides 
  the 
  San 
  Jos6 
  scale 
  there 
  are 
  a 
  few 
  other 
  kinds 
  of 
  Aspid- 
  

   iotus 
  infesting 
  fruits, 
  most 
  of 
  which 
  closely 
  resemble 
  the 
  San 
  Jose 
  

   species, 
  and 
  are 
  scarcely 
  to 
  be 
  distinguished 
  from 
  it 
  without 
  a 
  

   microscopic 
  examination 
  of 
  prepared 
  specimensof 
  the 
  female, 
  mount- 
  

   ed 
  on 
  microscope 
  slides. 
  The 
  case 
  is 
  (|uite 
  different, 
  however, 
  with 
  

   regard 
  to 
  the 
  other 
  common 
  fruit 
  scale 
  insects, 
  such 
  as 
  the 
  oyster- 
  

   shell, 
  the 
  scurfy 
  scale, 
  and 
  the 
  rose 
  scale, 
  which 
  are 
  often 
  supposed 
  

   to 
  be 
  the 
  San 
  Jose, 
  but 
  which 
  are 
  easily 
  distinguished 
  from 
  it 
  at 
  

   sight, 
  as 
  the 
  mode 
  of 
  growth 
  of 
  their 
  scales 
  is 
  on 
  quite 
  a 
  different 
  

   plan. 
  In 
  the 
  San 
  Jose 
  scale 
  and 
  its 
  allies 
  of 
  the 
  same 
  genus 
  ( 
  Aspid- 
  

   iotus) 
  the 
  starting 
  point 
  of 
  growth 
  — 
  the 
  larval 
  scale 
  — 
  is 
  usually 
  

   near 
  the 
  center 
  of 
  each 
  scale, 
  marked 
  by 
  a 
  minute 
  papilla 
  or 
  nipple 
  

   encircled 
  by 
  a 
  tiny 
  impressed 
  ring. 
  This 
  mark 
  is 
  usually 
  quite 
  evi- 
  

   dent 
  except 
  when 
  rubbed 
  off 
  from 
  the 
  older 
  scales. 
  Around 
  this 
  

   point 
  the 
  scale 
  grows 
  by 
  concentric 
  additions. 
  That 
  of 
  the 
  female 
  

   always 
  maintains 
  a 
  nearly 
  circular 
  form, 
  but 
  the 
  male 
  scale 
  when 
  

   about 
  half 
  grown 
  begins 
  to 
  enlarge 
  mostly 
  in 
  one 
  direction, 
  assum- 
  

   ing 
  an 
  oblong 
  or 
  oval 
  shape. 
  In 
  the 
  oyster-shell 
  and 
  scurfy 
  scales 
  

   (Mytilaspis, 
  Chionaspis), 
  on 
  the 
  other 
  hand, 
  the 
  starting 
  point 
  is 
  in- 
  

   dicated 
  by 
  a 
  minute 
  dark-colored 
  cast 
  skin 
  at 
  one 
  end, 
  from 
  which 
  

   growth 
  progresses 
  by 
  successive 
  additions 
  in 
  one 
  direction 
  only, 
  as 
  

   in 
  the 
  shell 
  of 
  an 
  oyster. 
  

  

  The 
  fruit-infesting 
  species 
  of 
  the 
  first 
  group 
  (Aspidiotus) 
  most 
  

   likely 
  to 
  be 
  confused 
  with 
  the 
  San 
  Jos6 
  scale 
  are 
  the 
  minor 
  fruit- 
  

   scale, 
  a 
  common 
  species 
  in 
  Illinois 
  (Aspidiotus 
  forbesi)^. 
  Putnam's 
  

   scale 
  (A. 
  ancijlus) 
  j, 
  the 
  obscure 
  scale 
  (A. 
  ohscuriis)X,find 
  Howard's 
  

   scale 
  (A. 
  liowardi)^. 
  The 
  minor 
  fruit 
  scale 
  seems 
  to 
  be 
  distinctly 
  

   whiter 
  than 
  the 
  San 
  Jos^ 
  scale, 
  the 
  younger 
  scales 
  especially 
  so, 
  and 
  

   never 
  dark-colored 
  as 
  in 
  the 
  imported 
  species. 
  I 
  have 
  seen 
  unusually 
  

   light 
  colored 
  specimens 
  of 
  the 
  San 
  Jose 
  on 
  currant 
  stems, 
  but 
  in 
  the 
  

   many 
  examples 
  of 
  apple 
  twigs 
  infested 
  by 
  both 
  species 
  examined 
  at 
  

   this 
  office, 
  the 
  difference 
  was 
  always 
  quite 
  evident. 
  Howard's 
  scale. 
  

   found 
  on 
  the 
  plum 
  in 
  Colorado, 
  resembles 
  the 
  San 
  Jos6 
  scale, 
  but 
  lacks 
  

   the 
  nipple 
  and 
  ring. 
  Putnam's 
  scale 
  is 
  also 
  similar 
  to 
  the 
  San 
  Jos4 
  in 
  

   external 
  appearance, 
  but 
  has 
  a 
  darker 
  color, 
  and 
  brighter 
  or 
  deeper 
  

   red 
  spots 
  in 
  the 
  center 
  of 
  the 
  older 
  scales, 
  and 
  the 
  nipple 
  and 
  ring 
  are 
  

   not 
  well 
  developed. 
  

  

  * 
  Johnson, 
  Bull. 
  111. 
  State 
  Lab. 
  Nat. 
  Hist.. 
  Vol. 
  IV.. 
  Art. 
  XIII., 
  p. 
  ;jsO, 
  IM. 
  XXIX. 
  

  

  + 
  Conistock, 
  Rep. 
  U. 
  S. 
  Ent., 
  1880, 
  p. 
  292, 
  PI, 
  XIV.. 
  Fig. 
  3; 
  PI. 
  XXI., 
  Fig. 
  4. 
  

  

  I 
  Ibid. 
  p. 
  303, 
  PI. 
  XII., 
  Fig. 
  4; 
  PI. 
  XIII., 
  Fig. 
  4. 
  

  

  i 
  Coikerell.Can. 
  Ent.,Vol. 
  XXVII., 
  p. 
  16; 
  Gillette, 
  Bull. 
  38, 
  Col. 
  Agr. 
  Exper. 
  St.ition, 
  p. 
  37. 
  

  

  