﻿CRICKET 
  PARASITE 
  GURNET 
  31 
  

  

  thorax 
  and 
  abdomen, 
  which 
  in 
  the 
  fourth 
  instar 
  vary 
  from 
  tightly 
  

   grouped 
  on 
  the 
  side 
  of 
  the 
  thorax 
  (fig. 
  9, 
  a) 
  to 
  narrowly 
  separated 
  on 
  

   the 
  abdomen, 
  are 
  much 
  less 
  closely 
  grouped 
  in 
  the 
  third 
  and 
  second 
  

   instars, 
  while 
  they 
  are 
  so 
  distant 
  and 
  reduced 
  in 
  size 
  in 
  the 
  first 
  instar 
  

   as 
  to 
  resemble 
  very 
  widely 
  spaced 
  spiculelike 
  spots 
  of 
  pigment. 
  

   Mandibles 
  of 
  the 
  third 
  and 
  second 
  instars 
  roughly 
  resemble 
  those 
  

   of 
  the 
  fourth, 
  and 
  bear 
  sharp 
  teeth, 
  there 
  being 
  at 
  least 
  six 
  to 
  eight 
  

   in 
  the 
  third 
  and 
  apparently 
  fewer 
  in 
  the 
  second. 
  The 
  epicranium 
  of 
  

   the 
  first 
  instar 
  has 
  about 
  two 
  pairs 
  of 
  rather 
  large 
  areas 
  of 
  darker 
  

   pigment, 
  but 
  no 
  mouth 
  parts 
  have 
  been 
  observed, 
  though 
  they 
  may 
  

   have 
  escaped 
  detection. 
  There 
  are 
  10 
  pairs 
  of 
  spiracles 
  in 
  the 
  third 
  

   and 
  second 
  instars, 
  with 
  the 
  pre-spiracular 
  tracheal 
  ring 
  poorly 
  defined. 
  

   Only 
  six 
  pairs 
  of 
  spiracles 
  have 
  been 
  found 
  on 
  the 
  exuviae 
  of 
  the 
  first 
  

   instar, 
  and 
  the 
  posterior 
  one 
  is 
  poorly 
  developed. 
  Each 
  of 
  the 
  three 
  

   early 
  instars 
  is 
  brown, 
  darker 
  on 
  the 
  head. 
  The 
  venter 
  is 
  pale 
  in 
  

   the 
  third 
  and 
  second 
  instars. 
  Approximate 
  lengths 
  of 
  the 
  exuviae 
  of 
  

   the 
  Falls 
  Chuch, 
  Va., 
  larva 
  are 
  as 
  follows 
  (in 
  millimeters) 
  : 
  Fourth 
  

   6.5 
  ; 
  third 
  3.6 
  ; 
  second 
  2.3 
  ; 
  first 
  1.2. 
  Those 
  of 
  the 
  Marietta, 
  Ga., 
  larva 
  

   are 
  almost 
  identical, 
  but 
  the 
  Fuguay, 
  N. 
  C, 
  larva 
  is 
  larger, 
  the 
  three 
  

   exuviae 
  measuring 
  as 
  follows 
  : 
  Third 
  4.4 
  ; 
  second 
  2.6 
  ; 
  first 
  1.3. 
  

  

  Eggs 
  apparently 
  are 
  broadly 
  elongate-oval; 
  fragments 
  are 
  about 
  

   1.4 
  millimeters 
  long. 
  

  

  A 
  basic 
  paper 
  on 
  the 
  larval 
  head 
  of 
  parasitic 
  Hymenoptera 
  is 
  that 
  

   of 
  Vance 
  and 
  Smith 
  (1933). 
  Among 
  the 
  more 
  specialized 
  papers, 
  

   those 
  of 
  G. 
  C. 
  Wheeler 
  (1943) 
  and 
  Beirne 
  (1941) 
  have 
  aided 
  me 
  most 
  

   while 
  studying 
  the 
  anatomy 
  of 
  fifth- 
  and 
  fourth-instar 
  heads, 
  re- 
  

   spectively, 
  of 
  Rhopalosoma. 
  The 
  book 
  by 
  Clausen 
  (1940) 
  is 
  a 
  val- 
  

   uable 
  aid 
  toward 
  understanding 
  the 
  biology 
  and 
  morphology 
  of 
  

   related 
  families, 
  and 
  it 
  should 
  be 
  consulted 
  for 
  references 
  to 
  the 
  im- 
  

   portant 
  work 
  of 
  J. 
  C. 
  Bridwell, 
  F. 
  A. 
  Fenton, 
  R. 
  C. 
  L. 
  Perkins, 
  F. 
  X. 
  

   Williams, 
  F. 
  van 
  Emden, 
  and 
  others. 
  

  

  Summary 
  and 
  discussion 
  

  

  Among 
  the 
  biological 
  data 
  additional 
  to 
  those 
  brought 
  out 
  by 
  Hood 
  

   (1914) 
  is 
  the 
  fact 
  that 
  Ha'pithus 
  agitator 
  is 
  an 
  acceptable 
  host 
  for 
  

   Rhopalosoma 
  in 
  the 
  eastern 
  United 
  States. 
  The 
  effect 
  of 
  the 
  parasite 
  

   on 
  the 
  internal 
  organs 
  of 
  the 
  host, 
  unfortunately 
  based 
  on 
  only 
  one 
  

   dissected 
  cricket, 
  has 
  been 
  described. 
  Details 
  concerning 
  the 
  position 
  

   of 
  the 
  parasite 
  egg 
  and 
  various 
  larval 
  stages 
  have 
  been 
  given. 
  Notes 
  

   on 
  adult 
  habits, 
  essentially 
  lacking 
  previously, 
  make 
  it 
  clear 
  that 
  in 
  

   parts 
  of 
  the 
  Southeast 
  specimens 
  of 
  Rhopalosoma 
  are 
  not 
  nearly 
  so 
  

   scarce 
  as 
  has 
  been 
  supposed. 
  Like 
  many 
  another 
  rarity 
  in 
  collections, 
  

   these 
  insects 
  can 
  doubtless 
  be 
  taken 
  in 
  numbers 
  by 
  those 
  familiar 
  with 
  

  

  