﻿104 
  

  

  tainiiig; 
  valve, 
  and 
  for 
  the 
  present 
  purpose 
  all 
  that 
  is 
  necessary 
  for 
  

   you 
  to 
  understand 
  is 
  that 
  if 
  the 
  openin.u,' 
  is 
  closed 
  up, 
  the 
  brakes 
  on 
  

   the 
  car 
  so 
  atliicted 
  cannot 
  be 
  drawn 
  off. 
  The 
  result 
  is 
  that 
  if 
  the 
  

   train 
  is 
  in 
  motion 
  the 
  brakes 
  will 
  remain 
  applied, 
  increasing 
  very 
  

   materially 
  the 
  coal 
  consumption 
  until 
  released, 
  and 
  in 
  case 
  of 
  the 
  

   rail 
  being 
  slippery 
  and 
  oily 
  probably 
  sliding 
  the 
  wheels 
  and 
  there- 
  

   fore 
  making 
  the 
  equipment 
  liable 
  to 
  accidents 
  and 
  wrecks 
  incident 
  

   to 
  having 
  flat 
  spots 
  on 
  wheels. 
  I 
  was 
  told 
  some 
  eight 
  or 
  nine 
  months 
  

   ago 
  that 
  this 
  trouble 
  was 
  one 
  of 
  frequent 
  occurrence." 
  

  

  In 
  a 
  later 
  letter 
  Superintendent 
  Rhodes 
  reports 
  that 
  more 
  retain- 
  

   ing 
  valves 
  are 
  found 
  stopped 
  up 
  by 
  wasps 
  in 
  cars 
  coming 
  from 
  the 
  

   Union 
  Pacific 
  Railroad 
  than 
  from 
  any 
  other 
  point. 
  In 
  an 
  illustrated 
  

   article* 
  on 
  the 
  subject, 
  published 
  after 
  considerable 
  correspondence 
  

   with 
  me, 
  Mr. 
  Rhodes 
  gives 
  full 
  details 
  of 
  the 
  construction 
  of 
  these 
  

   valves 
  and 
  of 
  the 
  nature 
  and 
  consequences 
  of 
  the 
  difficulty 
  described. 
  

  

  On 
  examination 
  of 
  the 
  contents 
  of 
  six 
  of 
  the 
  plugged 
  valves 
  kindly 
  

   sent 
  me 
  by 
  Mr. 
  Rhodes, 
  remains 
  were 
  found 
  of 
  caterpillars 
  which 
  

   had 
  evidently 
  been 
  stored 
  there 
  by 
  the 
  wasps 
  as 
  food 
  for 
  their 
  young, 
  

   and 
  in 
  one 
  such 
  valve 
  was 
  an 
  entire 
  specimen 
  of 
  a 
  common 
  and 
  

   widely 
  distributed 
  species 
  of 
  solitarj^ 
  wasp 
  iOdynerus 
  fornmiiiatus 
  

   Saussure 
  ) 
  . 
  

  

  The 
  habits 
  of 
  these 
  wasps 
  are 
  well 
  known 
  to 
  entomologists, 
  and 
  

   indeed 
  the 
  selection 
  of 
  a 
  somewhat 
  similar 
  nesting 
  place 
  by 
  a 
  species 
  

   of 
  this 
  genus 
  has 
  been 
  reported 
  by 
  Professor 
  Comstock, 
  of 
  Cornell 
  

   University, 
  in 
  his 
  "Manual 
  for 
  the 
  Study 
  of 
  Insects," 
  p. 
  659. 
  "One 
  

   year 
  these 
  wasps 
  plastered 
  up 
  many 
  of 
  the 
  keyholes 
  in 
  our 
  house, 
  in- 
  

   cluding 
  those 
  in 
  the 
  bureaus, 
  thus 
  constructing 
  for 
  us 
  locks 
  .that 
  re- 
  

   quired 
  a 
  good 
  deal 
  of 
  time 
  and 
  industry 
  on 
  our 
  part 
  to 
  oi3en." 
  

  

  Having 
  prepared 
  the 
  selected 
  cavity 
  for 
  htr 
  purpose 
  by 
  plastering 
  

   and 
  shaping 
  it 
  with 
  mud. 
  the 
  mother 
  wasp 
  brings 
  into 
  it 
  a 
  number 
  of 
  

   small 
  caterpillars 
  which 
  she 
  has 
  partially 
  paralyzed 
  by 
  stinging 
  them, 
  

   and 
  stores 
  them 
  there 
  as 
  living 
  food 
  for 
  her 
  young. 
  She 
  then 
  lays 
  

   an 
  egg 
  in 
  the 
  cavity, 
  closes 
  it 
  with 
  a 
  plug 
  of 
  mud 
  for 
  the 
  protection 
  of 
  

   the 
  larval 
  wasp 
  presently 
  to 
  appear 
  and 
  to 
  enjoy 
  in 
  due 
  time 
  the 
  re- 
  

   sources 
  thus 
  carefully 
  provided 
  for 
  it. 
  

  

  The 
  details 
  of 
  this 
  history 
  have 
  never 
  been 
  reported 
  for 
  this 
  partic- 
  

   ular 
  species 
  of 
  wasps, 
  but 
  they 
  may 
  be 
  illustrated, 
  no 
  doubt, 
  by 
  an 
  

   account 
  given 
  by 
  J. 
  H. 
  Fabre, 
  in 
  his 
  Souvenirs 
  Enfomologiques, 
  of 
  

   the 
  methods 
  of 
  a 
  related 
  species, 
  Odynerus 
  reniforniis 
  Latr., 
  which 
  

   may 
  be 
  thus 
  summarized: 
  

  

  From 
  the 
  roof 
  of 
  the 
  cavity 
  containing 
  her 
  paralyzed 
  prey 
  the 
  

   mother 
  spins 
  a 
  fine, 
  thread-like 
  spider 
  web. 
  at 
  the 
  end 
  of 
  which 
  she 
  

   suspends 
  an 
  egg. 
  The 
  young 
  larva 
  presently, 
  breaks 
  through 
  the 
  

   envelope 
  of 
  the 
  egg, 
  which 
  it 
  is 
  careful 
  not 
  to 
  leave, 
  its 
  weight 
  

   stretching 
  the 
  calile 
  by 
  which 
  the 
  egg 
  is 
  suspended, 
  so 
  that 
  by 
  reach- 
  

   ing 
  downward 
  it 
  may 
  get 
  at 
  the 
  first 
  caterpillar 
  of 
  the 
  series 
  placed 
  

   at 
  its 
  disposal. 
  On 
  being 
  attacked, 
  the 
  caterpillar 
  wriggles 
  and 
  

  

  * 
  "The 
  Air 
  Brake 
  Encounters 
  a 
  New 
  Enemy,'" 
  Proc. 
  Western 
  Railway 
  Club, 
  January, 
  

   1897. 
  pp. 
  218-22<t. 
  

  

  