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  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1922. 
  

  

  this 
  species 
  and 
  believed 
  it 
  necessary 
  to 
  change 
  the 
  name 
  to 
  P. 
  gib- 
  

   bosus 
  Fabricius, 
  a 
  synonym 
  that 
  was 
  intimated 
  by 
  Dalla 
  Torre 
  but 
  

   was 
  not 
  generally 
  followed 
  in 
  America. 
  

  

  The 
  male 
  of 
  gibbosus 
  resembles 
  the 
  female 
  very 
  closely, 
  but 
  differs 
  

   mainly 
  in 
  having 
  less 
  yellow 
  on 
  the 
  head 
  (fig. 
  1). 
  This 
  is 
  the 
  oppo- 
  

   site 
  of 
  the 
  usual 
  sexual 
  diversity 
  in 
  Hymenoptera. 
  Most 
  male 
  wasps 
  

   and 
  bees 
  have 
  more 
  light-colored 
  markings 
  on 
  the 
  face 
  than 
  the 
  

   female. 
  

  

  Philanthus 
  gibbosus 
  is 
  a 
  common 
  and 
  widely 
  distributed 
  Sphecid 
  

   of 
  North 
  America. 
  Specimens 
  in 
  the 
  United 
  States 
  National 
  

   Museum 
  collections 
  show 
  a 
  habitat 
  that 
  extends 
  from 
  Washington, 
  

   Colorado, 
  Arizona, 
  and 
  Texas 
  in 
  the 
  West 
  to 
  Georgia, 
  Virginia, 
  

   New 
  York, 
  and 
  Massachusetts 
  in 
  the 
  East. 
  There 
  are 
  specimens 
  in 
  

  

  ? 
  \sp 
  $ 
  

  

  Fig. 
  1. 
  — 
  Philanthus 
  gibbosus. 
  Heads 
  of 
  male 
  and 
  female. 
  

  

  the 
  collections 
  of 
  the 
  National 
  Museum 
  from 
  21 
  States, 
  as 
  well 
  as 
  

   from 
  Canada 
  and 
  Mexico. 
  

  

  THE 
  ANNUAL 
  CYCLE. 
  

  

  In 
  Maryland 
  Philanthus 
  gibbosus 
  goes 
  through 
  two 
  generations 
  

   a 
  year. 
  The 
  early 
  pioneers 
  begin 
  prospecting 
  for 
  a 
  nesting 
  site 
  dur- 
  

   ing 
  the 
  second 
  week 
  of 
  June; 
  but 
  some 
  laggards 
  do 
  not 
  start 
  to 
  dig 
  

   until 
  two 
  weeks 
  later. 
  By 
  the 
  end 
  of 
  June 
  the 
  establishment 
  is 
  in 
  

   full 
  swing. 
  For 
  about 
  three 
  weeks 
  each 
  wasp 
  applies 
  herself 
  to 
  the 
  

   task 
  of 
  provisioning 
  and 
  egg 
  laying, 
  and 
  then, 
  her 
  season 
  over, 
  she 
  

   dies. 
  

  

  During 
  the 
  middle 
  of 
  July 
  the 
  progeny 
  of 
  this 
  first 
  brood 
  begin 
  

   to 
  make 
  their 
  appearance, 
  and 
  the 
  gradual 
  emergence 
  continues 
  until 
  

   almost 
  the 
  end 
  of 
  August. 
  The 
  major 
  number 
  of 
  this 
  second 
  gen- 
  

   eration 
  have 
  provided 
  for 
  their 
  young 
  and 
  died 
  before 
  the 
  beginning 
  

   of 
  September. 
  A 
  few 
  stragglers, 
  however, 
  keep 
  on 
  with 
  their 
  task 
  

   until 
  more 
  than 
  a 
  fortnight 
  later. 
  The 
  larvae 
  pass 
  the 
  winter 
  in 
  

   their 
  cocoons, 
  change 
  to 
  pupae 
  in 
  April, 
  and 
  emerge 
  during 
  May 
  

   and 
  June, 
  and 
  thus 
  one 
  annual 
  cycle 
  is 
  complete. 
  

  

  