﻿METEOROLOGICAL 
  CONDITIONS 
  AND 
  THE 
  CHINCH-BUG. 
  

  

  It 
  has 
  long 
  been 
  held 
  by 
  entomologists 
  and 
  farmers 
  that 
  an 
  increase 
  in 
  

   humidity 
  insures 
  a 
  decrease 
  in 
  chinch-bugs, 
  and 
  similarly, 
  that 
  a 
  dry 
  season 
  

   means 
  a 
  season 
  of 
  bugs. 
  B. 
  D. 
  Walsh, 
  the 
  first 
  Illinois 
  State 
  Entomologist, 
  

   in 
  1861 
  published 
  a 
  paper 
  on 
  the 
  chinch-bug, 
  in 
  which 
  he 
  said 
  that 
  dry 
  

   weather 
  is 
  favorable 
  to 
  the 
  bug 
  and 
  wet 
  weather 
  unfavorable 
  to 
  it. 
  In 
  1869, 
  

   Messrs. 
  Walsh 
  and 
  Riley, 
  in 
  a 
  conjointly 
  written 
  article 
  on 
  the 
  chinch-bug, 
  

   published 
  in 
  the 
  American 
  Entomologist 
  for 
  May 
  and 
  June, 
  say 
  that 
  a 
  single 
  

   heavy 
  rain 
  immediately 
  checks 
  the 
  propagation 
  of 
  the 
  bugs, 
  and 
  that 
  a 
  long- 
  

   continued 
  wet 
  season 
  barely 
  leaves 
  enough 
  for 
  seed 
  another 
  year. 
  They 
  claim 
  

   that 
  the 
  insect 
  can 
  never 
  be 
  ruinously 
  destructive 
  except 
  in 
  sections 
  where 
  

   there 
  is 
  continued 
  hot, 
  dry 
  weather. 
  Wm. 
  Le 
  Baron, 
  following 
  Mr. 
  Walsh 
  

   as 
  Illinois 
  State 
  Entomologist, 
  in 
  an 
  article 
  in 
  the 
  Prairie 
  Farmer 
  for 
  Sep- 
  

   tember 
  2, 
  1871, 
  speaks 
  of 
  the 
  June 
  rains 
  as 
  an 
  important 
  check 
  upon 
  preva- 
  

   lence 
  of 
  chinch-bugs, 
  and 
  believes 
  that 
  it 
  (the 
  chinch-bug), 
  " 
  has 
  never 
  

   been 
  known 
  to 
  prevail 
  in 
  any 
  year 
  when 
  the 
  month 
  of 
  June 
  of 
  the 
  preced- 
  

   ing 
  year 
  has 
  been 
  attended 
  by 
  heavy 
  rains." 
  Cyrus 
  Thomas, 
  following 
  Le 
  

   Baron 
  as 
  State 
  Entomologist 
  of 
  Illinois, 
  in 
  an 
  article 
  entitled, 
  " 
  Chinch-bug," 
  

   in 
  the 
  seventh 
  report 
  of 
  the 
  State 
  Entomologist 
  of 
  Illinois, 
  says 
  that 
  rain 
  is 
  

   the 
  chief 
  natural 
  agency 
  which 
  works 
  against 
  the 
  chinch-bug, 
  destroying 
  

   eggs, 
  young, 
  and 
  adults. 
  

  

  An 
  important 
  contribution 
  to 
  the 
  discussion 
  of 
  the 
  influence 
  on 
  the 
  chinch- 
  

   bug 
  of 
  meteorological 
  conditions 
  was 
  made 
  by 
  Cyrus 
  Thomas, 
  in 
  an 
  article 
  

   in 
  the 
  American 
  Entomologist 
  for 
  October, 
  1880. 
  The 
  paper 
  is 
  entitled, 
  

   " 
  Temperature 
  and 
  Rainfall 
  as 
  Affecting 
  the 
  Chinch-bug." 
  Elaborate 
  data 
  

   both 
  of 
  weather 
  conditions 
  and 
  chinch-bug 
  prevalence 
  are 
  given. 
  He 
  finds 
  

   that 
  the 
  series 
  of 
  years 
  seem 
  to 
  be 
  divided 
  into 
  cycles 
  of 
  seven 
  as 
  to 
  rainfall, 
  

   the 
  rainfall 
  of 
  each 
  seventh 
  year 
  (counting 
  back 
  from 
  1876 
  to 
  1840) 
  being 
  

   above 
  the 
  average. 
  Each 
  septenary 
  period 
  also 
  seems 
  to 
  be 
  divided 
  into 
  two 
  

   periods 
  of 
  four 
  and 
  three 
  years 
  respectively, 
  the 
  ternary 
  period 
  ranking 
  first 
  

   as 
  to 
  rainfall 
  and 
  the 
  quaternary 
  second. 
  Considering 
  the 
  relation 
  of 
  the 
  

   rainfall 
  to 
  the 
  appearance 
  of 
  chinch-bugs, 
  and 
  "regarding 
  it 
  as 
  generally 
  ad- 
  

   mitted 
  that 
  two 
  successive 
  dry 
  years 
  are 
  necessary 
  to 
  the 
  development 
  of 
  these 
  

   insects 
  in 
  injurious 
  numbers," 
  he 
  finds 
  the 
  chronological 
  history 
  of 
  the 
  species 
  

   to 
  be 
  apparently 
  fairly 
  comformable 
  to 
  his 
  theory 
  of 
  rainfall 
  periodicity. 
  In 
  

   closing 
  he 
  says: 
  "The 
  high 
  temperature 
  of 
  1854, 
  1871, 
  and 
  1874, 
  together 
  

   with 
  the 
  diminished 
  rainfall, 
  furnish 
  the 
  key 
  to 
  the 
  cause 
  of 
  the 
  great 
  devel- 
  

   opment 
  of 
  the 
  chinch-bug 
  during 
  these 
  years." 
  

  

  In 
  a 
  closely 
  following 
  article. 
  entitled 
  the 
  "Relation 
  of 
  Meteorological 
  

   Conditions 
  to 
  Insect 
  Development," 
  published 
  in 
  the 
  Transactions 
  of 
  the 
  

  

  (173) 
  

  

  