﻿24 
  CONTAGIOUS 
  DISEASES 
  OF 
  THE 
  CHINCH-BUG. 
  

  

  IL— 
  LABORATORY 
  OBSERVATIONS 
  AND 
  EXPERIMENTS. 
  

  

  Our 
  laboratory 
  experiments 
  for 
  1891 
  with 
  the 
  diseases 
  of 
  the 
  chinch-bug 
  

   began 
  on 
  March 
  23. 
  On 
  this 
  date 
  we 
  stocked 
  eight 
  infection 
  jars 
  of 
  the 
  pre- 
  

   vious 
  summer 
  with 
  healthy 
  chinch-bugs 
  just 
  received 
  from 
  Chetopa, 
  Kas., 
  from 
  

   which 
  locality 
  no 
  disease 
  had 
  been 
  reported. 
  One 
  check 
  jar 
  was 
  stocked 
  from 
  

   the 
  same 
  lot 
  of 
  bugs. 
  Of 
  the 
  infection 
  jars, 
  No. 
  4, 
  which 
  contained 
  dead 
  

   bugs 
  of 
  the 
  previous 
  year 
  which 
  had 
  died 
  of 
  an 
  apparently 
  bacterial 
  disease, 
  

   showed 
  a 
  remarkable 
  virulence. 
  Up 
  to 
  May 
  2, 
  when 
  jar 
  No. 
  4 
  was 
  divided 
  

   to 
  supply 
  the 
  increasing 
  demand 
  by 
  the 
  farmers 
  for 
  infected 
  bugs, 
  the 
  bugs 
  

   in 
  jar 
  No. 
  4 
  had 
  died 
  at 
  intervals 
  of 
  from 
  four 
  to 
  five 
  days, 
  while 
  the 
  bugs 
  in 
  

   the 
  check 
  jar 
  remained 
  alive 
  and 
  active. 
  No 
  external 
  growth 
  of 
  fungus 
  ap- 
  

   peared 
  on 
  the 
  dead 
  bugs. 
  The 
  abdominal 
  contents 
  of 
  the 
  dying 
  and 
  dead 
  

   bugs 
  contained 
  a 
  Micrococcus, 
  apparently 
  Micrococcus 
  insectorum. 
  The 
  tem- 
  

   perature 
  of 
  the 
  laboratory 
  stood 
  uniformly 
  about 
  70° 
  F. 
  But 
  during 
  two 
  

   weeks 
  in 
  April 
  the 
  steam 
  was 
  shut 
  off 
  from 
  the 
  laboratory, 
  and 
  the 
  tempera- 
  

   ture 
  became 
  considerably 
  lowered. 
  At 
  this 
  time 
  the 
  bugs 
  did 
  not 
  all 
  die 
  in 
  

   jar 
  No. 
  4 
  till 
  nine 
  days 
  had 
  elapsed. 
  

  

  On 
  May 
  23 
  we 
  distributed 
  some 
  fungus-covered 
  bugs 
  from 
  the 
  field 
  of 
  Mr. 
  

   Mattocks 
  in 
  six 
  infection 
  jars. 
  Into 
  the 
  jars 
  had 
  been 
  put 
  soil 
  taken 
  from 
  

   the 
  yard, 
  and 
  green 
  wheat. 
  Fresh 
  chinch-bugs 
  sent 
  by 
  the 
  farmers 
  were 
  put 
  

   into 
  the 
  jars 
  — 
  enough 
  to 
  thickly 
  cover 
  the 
  bottom. 
  The 
  jars 
  were 
  covered 
  

   with 
  cheese 
  cloth, 
  and 
  set 
  into 
  a 
  glass 
  case 
  containing 
  moist 
  sand. 
  The 
  soil 
  

   in 
  the 
  infection 
  jars 
  was 
  not 
  watered, 
  so 
  that 
  the 
  bugs 
  were 
  in 
  a 
  humid 
  at- 
  

   mosphere, 
  but 
  not 
  in 
  contact 
  with 
  water. 
  We 
  were 
  in 
  this 
  way 
  able 
  to 
  se- 
  

   cure 
  the 
  best 
  conditions 
  for 
  the 
  development 
  of 
  the 
  fungus. 
  When 
  the 
  bugs 
  

   died 
  in 
  the 
  jars, 
  new 
  bugs 
  from 
  the 
  field 
  were 
  put 
  in, 
  the 
  date 
  of 
  restocking 
  

   being 
  also 
  a 
  record 
  of 
  the 
  time 
  when 
  the 
  bugs 
  in 
  the 
  jars 
  had 
  nearly 
  all 
  died. 
  

   The 
  following 
  is 
  the 
  memorandum 
  for 
  the 
  six 
  jars 
  started 
  May 
  23: 
  

  

  May 
  23; 
  June 
  4; 
  June 
  20. 
  

  

  May 
  23; 
  May 
  27; 
  June 
  4; 
  June 
  20. 
  

  

  May 
  23; 
  May 
  27; 
  June 
  4; 
  June 
  15. 
  

  

  May 
  23; 
  June 
  4; 
  June 
  15. 
  

  

  May 
  23; 
  May 
  27; 
  June 
  4; 
  June 
  15; 
  June 
  20. 
  

  

  May 
  23; 
  May 
  27; 
  June 
  4; 
  June 
  15; 
  June 
  20. 
  

  

  Seven 
  jars 
  were 
  started 
  May 
  25. 
  Their 
  record 
  is 
  as 
  follows 
  : 
  

  

  