﻿art. 
  8 
  REVISION 
  OF 
  THE 
  GENUS 
  MICROBRACON 
  MUESEBECK 
  5 
  

  

  mead 
  Microbracon 
  is 
  at 
  once 
  distinguished 
  by 
  the 
  propodeal 
  spiracles 
  

   which 
  are 
  small 
  and 
  round 
  while 
  in 
  the 
  former 
  they 
  are 
  large 
  and 
  

   linear; 
  the 
  unusually 
  long 
  scape 
  further 
  distinguishes 
  C 
  omp 
  sob 
  r 
  aeon. 
  

   Zavipio 
  Viereck 
  is 
  readily 
  separated 
  by 
  its 
  rostriform 
  head, 
  with 
  the 
  

   accompanying 
  very 
  long 
  malar 
  space, 
  and 
  by 
  the 
  usually 
  very 
  short 
  

   radial 
  cell. 
  

  

  Habrobracon 
  (Ashmead) 
  Johnson, 
  Macrodyctium 
  Ashmead, 
  

   Tropidobracon 
  Ashmead, 
  Liobracon 
  (Ashmead) 
  Nason, 
  not 
  Szepli- 
  

   geti, 
  and 
  Amy 
  o 
  soma 
  Viereck 
  can 
  not 
  be 
  held 
  distinct 
  from 
  Micro- 
  

   bracon. 
  These 
  groups 
  intergrade 
  completely, 
  so 
  that 
  it 
  is 
  entirely 
  

   impossible 
  to 
  determine 
  where 
  one 
  ends 
  and 
  another 
  begins. 
  The 
  

   characters 
  upon 
  which 
  they 
  have 
  been 
  separated 
  are 
  by 
  no 
  means 
  

   sufficiently 
  distinct 
  or 
  constant 
  to 
  serve 
  to 
  distinguish 
  genera. 
  The 
  

   genotypes 
  of 
  all 
  must, 
  I 
  believe, 
  be 
  regarded 
  as 
  congeneric 
  even 
  

   by 
  those 
  disposed 
  toward 
  a 
  large 
  increase 
  in 
  the 
  number 
  of 
  genera, 
  

   if 
  a 
  thorough 
  study 
  is 
  made 
  of 
  the 
  group. 
  

  

  In 
  few 
  groups 
  of 
  the 
  Braconidae 
  is 
  there 
  found 
  so 
  wide 
  a 
  range 
  of 
  

   variation 
  within 
  species 
  as 
  in 
  Microbracon. 
  Practically 
  all 
  charac- 
  

   ters, 
  many 
  of 
  them 
  excellent 
  characters 
  in 
  other 
  groups, 
  vary 
  greatly 
  

   in 
  this 
  genus. 
  Because 
  of 
  this 
  it 
  is 
  always 
  extremely 
  desirable 
  to 
  

   have 
  before 
  one 
  a 
  good 
  series 
  of 
  specimens 
  when 
  attempting 
  identifi- 
  

   cations. 
  The 
  males 
  are 
  particularly 
  difficult, 
  exhibiting 
  still 
  wider 
  

   variations 
  than 
  the 
  females, 
  and 
  single 
  specimens 
  of 
  this 
  sex 
  can 
  

   sometimes 
  be 
  only 
  doubtfully 
  named. 
  Host 
  records 
  are 
  often 
  of 
  

   much 
  value, 
  for 
  although 
  few, 
  if 
  any, 
  of 
  the 
  species 
  are 
  restricted 
  

   to 
  single 
  hosts, 
  and 
  frequently 
  the 
  same 
  species 
  attacks 
  both 
  lepidop- 
  

   terous 
  and 
  coleopterous 
  larvae, 
  still 
  one 
  species 
  usually 
  parasitizes 
  

   hosts 
  of 
  the 
  same 
  general 
  habit 
  or 
  found 
  in 
  the 
  same 
  food 
  plants. 
  In 
  

   a 
  consideration 
  of 
  specific 
  characters 
  in 
  Microbracon 
  one 
  is 
  impressed 
  

   by 
  the 
  lack 
  of 
  constancy 
  in 
  color 
  or 
  even 
  color 
  pattern, 
  although 
  

   sometimes 
  there 
  is 
  a 
  degree 
  of 
  uniformity 
  which 
  is 
  of 
  a 
  little 
  help 
  

   and 
  permits 
  the 
  employment 
  of 
  color 
  characters 
  to 
  a 
  small 
  extent 
  

   in 
  a 
  table 
  to 
  species. 
  The 
  color 
  of^ 
  the 
  face 
  and 
  legs 
  — 
  whether 
  face 
  

   and 
  coxae 
  are 
  yellowish 
  or 
  black 
  — 
  will 
  be 
  found 
  of 
  considerable 
  

   help, 
  although 
  varying 
  to 
  a 
  slight 
  degree. 
  The 
  wings 
  are 
  usually 
  

   somewhat 
  fuscous, 
  rarely 
  clear 
  hyaline, 
  but 
  the 
  degree 
  of 
  infusca- 
  

   tion 
  varies 
  more 
  or 
  less 
  within 
  the 
  species, 
  and 
  alone 
  is 
  not 
  de- 
  

   pendable 
  for 
  the 
  separation 
  of 
  species. 
  In 
  sculpture 
  there 
  is 
  likewise 
  

   so 
  much 
  variation 
  that 
  it 
  becomes 
  difficult 
  to 
  use 
  sculptural 
  char- 
  

   acters 
  in 
  a 
  key 
  without 
  qualification, 
  although 
  the 
  presence 
  or 
  ab- 
  

   sence 
  of 
  punctate 
  or 
  reticulate 
  sculpture 
  on 
  the 
  frons, 
  and 
  on 
  the 
  

   mesonotum, 
  pleura 
  and 
  propodeum 
  is 
  very 
  reliable. 
  The 
  abdominal 
  

   sculpture 
  is 
  variable 
  but 
  can 
  be 
  relied 
  upon 
  to 
  a 
  large 
  degree 
  for 
  

  

  