﻿NATURAL 
  ENEMIES 
  OF 
  THE 
  LOCUST. 
  267 
  

  

  described 
  in 
  our 
  First 
  Report 
  (p. 
  305), 
  and 
  is 
  found 
  in 
  the 
  locust 
  egg- 
  

   pods 
  or 
  near 
  them, 
  of 
  different 
  sizes, 
  during 
  most 
  of 
  the 
  year. 
  These 
  

   larvae 
  begin 
  to 
  transform 
  to 
  the 
  pupa 
  state 
  early 
  in 
  the 
  summer, 
  and 
  the 
  

   pupa 
  (PL 
  XVI, 
  Fig. 
  2) 
  pushes 
  itself 
  half 
  way 
  out 
  of 
  the 
  ground 
  in 
  order 
  

   to 
  disclose 
  the 
  fly. 
  These 
  flies 
  continue 
  to 
  issue 
  during 
  the 
  summer 
  

   months. 
  As 
  a 
  rule 
  but 
  one 
  year 
  is 
  required 
  for 
  full 
  development, 
  but 
  

   there 
  is, 
  in 
  this 
  respect, 
  great 
  irregularity 
  and 
  the 
  same 
  tendency 
  to 
  re- 
  

   tardation 
  which 
  we 
  have 
  called 
  attention 
  to 
  in 
  the 
  case 
  of 
  the 
  blister- 
  

   beetles. 
  We 
  have 
  had 
  quite 
  a 
  number 
  of 
  the 
  larvae 
  remain 
  over 
  un- 
  

   changed 
  till 
  the 
  second 
  year, 
  and 
  all 
  that 
  we 
  have 
  said 
  as 
  to 
  the 
  philoso- 
  

   phy 
  of 
  this 
  retardation 
  in 
  the 
  one 
  case 
  applies 
  in 
  the 
  other. 
  We 
  are 
  

   inclined 
  to 
  think 
  that 
  future 
  observation 
  will 
  show 
  that 
  there 
  is 
  a 
  still 
  

   further 
  parallel, 
  in 
  that 
  the 
  newly-hatched 
  larvae 
  of 
  the 
  bee-flies 
  are 
  much 
  

   more 
  active 
  than 
  the 
  later 
  stages, 
  and 
  somewhat 
  different 
  in 
  structure. 
  

   The 
  three 
  later 
  stages 
  of 
  the 
  insect 
  may 
  be 
  characterized 
  as 
  follows 
  : 
  

  

  Larva 
  (PI. 
  XVI, 
  Fig. 
  1). 
  — 
  We 
  quote 
  herewith 
  our 
  former 
  description 
  : 
  

   Average 
  length, 
  0.50 
  inch. 
  Body 
  curved, 
  glabrous, 
  tapering 
  posteriorly, 
  swollen 
  

   anteriorly. 
  Color 
  opaque 
  whitish, 
  with 
  translucent 
  yellowish 
  mottlings, 
  and 
  some 
  

   venous 
  marks 
  at 
  sutures, 
  especially 
  along 
  medio-dorsum. 
  Sutures 
  deep. 
  A 
  lateral 
  

   row 
  of 
  swellings. 
  Head 
  small, 
  flattened, 
  dark 
  brown, 
  in 
  five 
  pieces, 
  consisting 
  above 
  

   of 
  a 
  frontal 
  ovoid 
  piece 
  and 
  two 
  lateral 
  pieces 
  of 
  somewhat 
  similar 
  form, 
  and 
  each 
  

   bearing 
  near 
  tip 
  a 
  minute, 
  two-jointed 
  palpus 
  ; 
  beneath 
  of 
  two 
  broad, 
  sub 
  triangular 
  

   jaws, 
  having 
  forward 
  and 
  lateral 
  motion, 
  and 
  each, 
  also, 
  bearing 
  near 
  the 
  center, 
  in 
  

   a 
  depression, 
  a 
  two-jointed 
  feeler. 
  A 
  spiracle 
  each 
  side 
  in 
  a 
  fold 
  between 
  joints 
  2 
  and 
  

   3, 
  and 
  another 
  on 
  each 
  side 
  of 
  the 
  penultimate 
  joint, 
  12. 
  None 
  otherwise 
  perceptible. 
  

  

  With 
  additional 
  material 
  we 
  have 
  been 
  enabled 
  to 
  examine 
  more 
  fully 
  the 
  structure 
  

   of 
  the 
  head. 
  Underneath 
  the 
  median 
  elevated 
  piece 
  which 
  may 
  represent 
  the 
  labrum 
  

   we 
  find 
  two 
  stout 
  spines 
  (PI. 
  XVI, 
  Fig. 
  1 
  e), 
  faintly 
  notched 
  on 
  the 
  outer 
  edge, 
  

   which 
  are 
  doubtless 
  the 
  mandibles 
  and 
  correspond 
  to 
  the 
  two 
  dark 
  lance-like 
  man- 
  

   dibles 
  of 
  other 
  Dipterous 
  lar/ae, 
  for 
  they 
  are 
  retractile 
  and 
  run 
  back 
  into 
  the 
  thoracic 
  

   joints, 
  and 
  remain 
  after 
  the 
  other 
  trophi 
  are 
  detached. 
  The 
  pair 
  of 
  feelers 
  upon 
  the 
  

   upper 
  lateral 
  pieces, 
  which 
  seem 
  to 
  have 
  no 
  motion, 
  might 
  then 
  represent 
  the 
  antenna© 
  

   and 
  the 
  two 
  lower 
  jaws 
  the 
  maxillae 
  with 
  their 
  palpi, 
  while 
  the 
  labium 
  is 
  shown 
  in 
  a 
  

   chitinous 
  point 
  visible 
  only 
  when 
  the 
  larva 
  extends 
  and 
  raises 
  the 
  other 
  parts. 
  A 
  pe- 
  

   culiarity 
  in 
  the 
  movement 
  of 
  the 
  maxillae 
  or 
  the 
  lower 
  pair 
  of 
  horny 
  pieces 
  is 
  worthy 
  of 
  

   note. 
  They 
  move 
  in 
  alternation 
  with 
  one 
  another 
  in 
  the 
  forward 
  and 
  backward, 
  i. 
  e. 
  

   up 
  and 
  down, 
  motion. 
  The 
  palpus 
  of 
  these 
  lower 
  pieces 
  when 
  viewed 
  from 
  above 
  is, 
  

   as 
  represented 
  in 
  the 
  figure 
  (PI. 
  XVI, 
  Fig. 
  1 
  d), 
  circular, 
  with 
  two 
  dark 
  marks 
  indicating 
  

   minute 
  appendages. 
  

  

  When 
  the 
  larva 
  is 
  fresh 
  and 
  plump 
  it 
  shows 
  the 
  greater 
  swelling 
  of 
  the 
  thoracic 
  

   joints 
  and 
  the 
  translucent 
  mottlings 
  mentioned 
  above. 
  Toward 
  the 
  period 
  of 
  pupa- 
  

   tion 
  it 
  becomes 
  more 
  opaque 
  and 
  more 
  contracted. 
  336 
  

  

  Pupa 
  (PL 
  XVI, 
  Fig. 
  2). 
  — 
  Average 
  length 
  8.5 
  miu 
  . 
  Color 
  honey-yellow, 
  but 
  varying 
  with 
  

   age, 
  the 
  head 
  and 
  thorax 
  assuming 
  a 
  dark 
  color 
  with 
  maturity. 
  Head 
  narrow, 
  with 
  two 
  

   sets 
  of 
  3 
  stout, 
  dark 
  spines 
  on 
  the 
  top, 
  all 
  on 
  a 
  common 
  prominence, 
  the 
  two 
  lower 
  ones 
  

   of 
  each 
  set 
  connected 
  at 
  base 
  ; 
  a 
  pair 
  of 
  smaller 
  frontal 
  spines 
  near 
  the 
  base 
  of 
  proboscis, 
  

  

  336 
  So 
  far 
  as 
  we 
  can 
  ascertain, 
  there 
  has 
  hitherto 
  been 
  published 
  no 
  recognizable 
  figure 
  

   of 
  the 
  Bombyliid 
  larva. 
  Dufour, 
  in 
  his 
  articles 
  above 
  alluded 
  to, 
  describes 
  that 
  of 
  

   Bonibylius 
  major 
  very 
  indifferently 
  and 
  gives 
  a 
  dorsal 
  view 
  which 
  shows 
  little 
  or 
  no 
  

   relation 
  to 
  the 
  larva 
  here 
  described, 
  while 
  his 
  description 
  and 
  figure 
  of 
  the 
  mouth 
  

   parts 
  fail 
  to 
  indicate 
  the 
  different 
  pieces 
  we 
  have 
  observed 
  in 
  our 
  larvae. 
  Yet 
  in 
  gen- 
  

   eral 
  form 
  and 
  structure 
  the 
  true 
  Bombylius 
  larva 
  will 
  undoubtedly 
  be 
  found 
  to 
  agree 
  

   very 
  closely 
  with 
  those 
  here 
  described. 
  

  

  