﻿128 
  EXPORT 
  UNITED 
  STATES 
  ENTOMOLOGICAL 
  COMMISSION. 
  

  

  Variations 
  between 
  months 
  of 
  consecutive 
  years 
  — 
  Continued. 
  

  

  Tears 
  and 
  stations. 
  

  

  December. 
  

  

  January. 
  

  

  February. 
  

  

  Mean. 
  

  

  VIRGINIA 
  CITY. 
  

   1872-73 
  r 
  

  

  18.8 
  

   16.7 
  

   24.9 
  

   30.5 
  

   24.4 
  

   24.0 
  

  

  19.0 
  

   25.2 
  

   28.4 
  

   33.5 
  

   19.2 
  

   39.2 
  

  

  23.4 
  

   23.1 
  

   1.7 
  

   17.1 
  

   18.8 
  

   23.1 
  

  

  16.9 
  

  

  22.3 
  

   16.1 
  

   26.8 
  

   20.2 
  

   28.9 
  

  

  15.6 
  

  

  18.4 
  

  

  22.8 
  

  

  28.1 
  

  

  27.5- 
  

  

  27.9 
  

  

  26.9 
  

   23.4 
  

   13.8 
  

   30.1 
  

   37.3 
  

   36.9 
  

  

  19.3 
  

  

  1873-74 
  

  

  19 
  2 
  

  

  1874-75 
  

  

  19 
  8 
  

  

  1875-76 
  

  

  25 
  2 
  

  

  1876 
  77 
  

  

  23 
  6 
  

  

  1877 
  78 
  

  

  25 
  

  

  OMAHA. 
  

   1872-73 
  

  

  20.9 
  

  

  1873-74 
  

  

  23.6 
  

  

  1874-75 
  

  

  19.4 
  

  

  1875-76 
  

  

  30.1 
  

  

  1876-77 
  

  

  25.6 
  

  

  1877-78 
  

  

  35.0 
  

  

  

  

  It 
  will 
  be 
  seen 
  by 
  comparing 
  these 
  means 
  that 
  as 
  a 
  very 
  general 
  rule 
  

   the 
  temperature 
  was 
  higher 
  in 
  the 
  winters 
  of 
  1873-'74 
  and 
  1875-'76 
  

   than 
  the 
  preceding 
  or 
  following 
  winters, 
  but 
  that 
  to 
  this 
  rule 
  the 
  winter 
  

   of 
  1877-'78 
  forms 
  a 
  remarkable 
  exception. 
  But 
  in 
  these 
  cases 
  the 
  win- 
  

   ters 
  appear 
  to 
  correspond 
  with 
  the 
  general 
  character 
  of 
  the 
  year. 
  The 
  

   results 
  are 
  scarcely 
  sufficiently 
  marked 
  and 
  uniform 
  to 
  justify 
  the 
  con- 
  

   clusion 
  that 
  they 
  present 
  a 
  clew 
  to 
  the 
  solution 
  of 
  the 
  problem. 
  

  

  An 
  inspection 
  of 
  the 
  summer 
  months 
  in 
  Table 
  VI 
  shows 
  a 
  much 
  

   smaller 
  variation 
  ; 
  for 
  example, 
  at 
  Breckenridge, 
  where 
  the 
  differences 
  

   between 
  the 
  winter 
  means 
  are 
  the 
  greatest, 
  the 
  summer 
  means 
  are 
  as 
  

   follows: 
  1873, 
  52°.2; 
  1874, 
  53o.4; 
  1875, 
  51O.0; 
  1876, 
  520.6; 
  1877, 
  52°.6; 
  

   the 
  extreme 
  variation 
  being 
  but 
  2°.4. 
  

  

  Yankton 
  : 
  

  

  1874 
  65°.2 
  

  

  1875 
  61°.4 
  

  

  1876 
  62°9 
  

  

  1877 
  T 
  63°.l 
  

  

  Virginia 
  City 
  : 
  

  

  1874 
  53°.8 
  

  

  1875 
  53°.6 
  

  

  1876 
  53°.0 
  

  

  1877 
  5'2°.6 
  

  

  A 
  longer 
  series 
  of 
  years 
  would 
  doubtless 
  show 
  greater 
  variations, 
  but 
  

   if 
  these 
  furnish 
  any 
  indication 
  of 
  the 
  general 
  rule, 
  it 
  is 
  evident 
  the 
  

   means 
  of 
  summer 
  temperature 
  furnish 
  no 
  such 
  differences 
  as 
  would 
  

   seem 
  to 
  be 
  required 
  for 
  such 
  important 
  results. 
  So 
  far, 
  then, 
  as 
  the 
  

   records 
  of 
  temperature 
  thus 
  far 
  examined 
  are 
  concerned, 
  neither 
  the 
  an- 
  

   nual 
  nor 
  the 
  monthly 
  means 
  show 
  any 
  important 
  fact 
  to 
  sustain 
  the 
  

   assumption 
  that 
  unusual 
  heat 
  is 
  one 
  of 
  the 
  conditions 
  necessary 
  to 
  the 
  

   excessive 
  development 
  of 
  the 
  locusts. 
  If 
  they 
  show 
  any 
  important 
  fact 
  

   bearing 
  upon 
  the 
  subject, 
  it 
  is 
  that 
  the 
  winter 
  season 
  (including 
  March) 
  

   has 
  more 
  to 
  do 
  with 
  their 
  development 
  than 
  the 
  temperature 
  of 
  the 
  sum- 
  

   mer 
  season. 
  

  

  