﻿368 
  JOURNAL 
  OF 
  THE 
  WASHINGTON 
  ACADEMY 
  OF 
  SCIENCES 
  VOL. 
  12, 
  NO. 
  16 
  

  

  have 
  acquired 
  a 
  new 
  aspect. 
  It 
  was 
  shown 
  by 
  Cobb 
  (4,5,6), 
  Menzel 
  

   (13) 
  and 
  other 
  investigators 
  that 
  there 
  are 
  in 
  the 
  soil 
  certain 
  species, 
  

   and 
  even 
  whole 
  genera, 
  of 
  nemas, 
  which 
  in 
  some 
  cases 
  are, 
  and 
  in 
  others 
  

   may 
  be, 
  predatory 
  and 
  doubtless 
  at 
  least 
  occasionally, 
  are 
  feeding 
  on 
  

   other 
  kinds 
  of 
  nemas, 
  and 
  even 
  species 
  known 
  as 
  nema-pests. 
  Cobb 
  

   recorded 
  a 
  series 
  of 
  such 
  observations 
  (4) 
  and 
  suggested 
  first 
  the 
  possi- 
  

   bility 
  of 
  using 
  these 
  predatory 
  nemas 
  as 
  a 
  means 
  of 
  decreasing 
  the 
  

   number 
  of 
  plant 
  injurious 
  nemas 
  in 
  the 
  soil. 
  

  

  In 
  a 
  more 
  recent 
  paper 
  Dr. 
  Menzel 
  (13) 
  compiled 
  all 
  the 
  recorded 
  

   facts 
  and 
  observations 
  on 
  food 
  and 
  feeding 
  habits 
  from 
  the 
  literature 
  on 
  

   free-living 
  nemas. 
  He 
  performed 
  also 
  some 
  experiments 
  with 
  a 
  species 
  

   of 
  Mononchus, 
  corroborating 
  the 
  observations 
  of 
  Cobb. 
  He 
  observed 
  

   that 
  Mononchus 
  papillatus, 
  brought 
  together 
  with 
  Tylenchus 
  sp., 
  

   Plectus 
  auriculatus, 
  Tripyla 
  media 
  and 
  Anguillula 
  aceti, 
  attacked 
  these 
  

   forms, 
  and 
  killed 
  them 
  either 
  by 
  sucking 
  out 
  their 
  vitals, 
  or 
  by 
  swallow- 
  

   ing 
  them 
  whole. 
  

  

  Cobb 
  therefore 
  advocated 
  an 
  investigation 
  of 
  the 
  relationship 
  be- 
  

   tween 
  predatory 
  Mononchus 
  species 
  and 
  other 
  soil-inhabiting 
  and 
  

   plant-infesting 
  nemas, 
  especially 
  Heterodera. 
  If 
  possible 
  the 
  investiga- 
  

   tions 
  should 
  show 
  to 
  what 
  extent 
  the 
  above 
  mentioned 
  facts 
  regarding 
  

   the 
  feeding 
  habits 
  of 
  some 
  mononchs 
  are 
  a 
  true 
  expression 
  of 
  the 
  life 
  

   habits 
  of 
  these 
  animals. 
  If 
  they 
  prove 
  to 
  be 
  a 
  true 
  expression, 
  methods 
  

   for 
  the 
  propagating 
  and 
  rearing 
  of 
  Mononchus 
  should 
  be 
  studied 
  with 
  

   the 
  view 
  to 
  applying 
  the 
  results 
  for 
  practical 
  purposes 
  in 
  agriculture, 
  

   especially 
  for 
  fighting 
  the 
  root-knot 
  nema, 
  Heterodera 
  radicicola. 
  

  

  The 
  first 
  thing 
  for 
  us 
  to 
  find 
  out 
  was 
  the 
  life 
  history, 
  food, 
  and 
  feeding 
  

   habits 
  of 
  the 
  predatory 
  mononchs. 
  We 
  chose 
  for 
  our 
  investigations 
  

   Mononchus 
  papillatus 
  Bastian, 
  a 
  species 
  which 
  appeared 
  to 
  be 
  best 
  

   fitted, 
  first 
  because 
  it 
  seemed 
  one 
  of 
  the 
  easiest 
  to 
  obtain, 
  being 
  among 
  

   the 
  commonest 
  of 
  mononchs, 
  and 
  second 
  because 
  many 
  observations 
  

   have 
  been 
  made 
  on 
  the 
  voracity 
  of 
  this 
  form. 
  

  

  Recent 
  investigators 
  (1-3, 
  8-12 
  and 
  14-18) 
  have 
  reared 
  free-living 
  

   nemas, 
  but 
  as 
  far 
  as 
  we 
  know, 
  mostly 
  forms 
  which 
  feed 
  on 
  decaying 
  

   matter, 
  and 
  therefore 
  in 
  most 
  cases 
  easily 
  reared 
  in 
  a 
  small 
  amount 
  of 
  

   suitable 
  medium 
  on 
  slides 
  or 
  in 
  watchglasses. 
  Berliner 
  and 
  Busch 
  

   and 
  also 
  Byars 
  were 
  the 
  first 
  who 
  used 
  agar 
  as 
  a 
  culture 
  medium 
  for 
  

   true 
  soil 
  nemas, 
  although 
  the 
  nemas 
  they 
  experimented 
  on 
  were 
  plant- 
  

   parasites, 
  namely: 
  Heterodera 
  schachtii 
  and 
  Heterodera 
  radicicola. 
  

   They 
  planted 
  seeds 
  of 
  oats, 
  etc. 
  on 
  agar 
  and 
  then 
  nematized 
  it 
  with 
  

   eggs 
  and 
  larvae 
  of 
  Heterodera. 
  

  

  