﻿533 
  

  

  the 
  larvae 
  hatch 
  in 
  the 
  second 
  half 
  of 
  summer 
  ; 
  they 
  are 
  nomadic 
  

   and 
  are 
  found 
  in 
  July, 
  August 
  and 
  September 
  in 
  large 
  numbers 
  

   on 
  the 
  surface 
  of 
  the 
  earth, 
  on 
  certain 
  plants, 
  stalks 
  of 
  grain, 
  in 
  wood, 
  

   etc., 
  from 
  which 
  they 
  pass 
  as 
  soon 
  as 
  occasion 
  offers 
  to 
  the 
  bodies 
  of 
  

   men 
  ; 
  the 
  method 
  of 
  attack 
  is 
  described 
  and 
  several 
  cases 
  are 
  cited 
  ; 
  

   the 
  larvae 
  having 
  sucked 
  sufficient 
  blood, 
  drop 
  off 
  their 
  victims, 
  moult, 
  

   pass 
  into 
  the 
  nymphal 
  stage 
  and 
  produce 
  the 
  adult 
  mite, 
  which 
  winters 
  

   and 
  proceeds 
  to 
  multiply 
  in 
  the 
  following 
  year. 
  The 
  eggs 
  laid 
  by 
  one 
  

   female 
  number 
  sometimes 
  400. 
  These 
  mites 
  are 
  less 
  connected 
  with 
  

   grain 
  crops, 
  living 
  on 
  the 
  latter 
  only 
  occasionally 
  ; 
  their 
  usual 
  abodes 
  

   are 
  gardens, 
  market-gardens, 
  stalls 
  and 
  similar 
  buildings. 
  

  

  Tyroglyphus 
  (Aleurobius) 
  farinae, 
  Koch, 
  is 
  the 
  most 
  important 
  species 
  

   of 
  mite 
  found 
  in 
  grain 
  and 
  flour, 
  doing 
  the 
  greatest 
  damage 
  to 
  the 
  latter 
  

   in 
  the 
  presence 
  of 
  moisture 
  and 
  warmth, 
  and 
  is 
  often 
  carried 
  with 
  

   cargoes 
  of 
  grain 
  to 
  other 
  countries. 
  In 
  France, 
  this 
  mite 
  prefers 
  barley 
  

   to 
  all 
  other 
  grain. 
  It 
  breeds 
  in 
  wet 
  or 
  musty 
  flour, 
  such 
  as 
  is 
  often 
  

   used 
  for 
  paste, 
  and 
  is 
  consequently 
  often 
  found 
  underneath 
  wall 
  paper, 
  

   in 
  factories 
  where 
  such 
  paste 
  is 
  used 
  and 
  in 
  cheese. 
  

  

  Tyroglyphus 
  siro, 
  L., 
  is 
  found 
  principally 
  in 
  many 
  sorts 
  of 
  cheese, 
  

   but 
  also 
  occurs 
  on 
  many 
  other 
  objects, 
  such 
  as 
  flour, 
  dust, 
  hair 
  used 
  

   for 
  stuffing 
  furniture, 
  hay, 
  etc., 
  and 
  together 
  with 
  Tyroglyphus 
  longior, 
  

   Gerv., 
  is 
  responsible 
  for 
  a 
  disease 
  called 
  "vanillism," 
  described 
  by 
  

   Layet, 
  which 
  is 
  common 
  among 
  workmen 
  engaged 
  in 
  cleaning 
  

   vanilla, 
  Tyroglyphus 
  longior, 
  Gerv., 
  is 
  more 
  active 
  than 
  T. 
  siro 
  and 
  

   is 
  found 
  on 
  various 
  articles 
  of 
  animal 
  or 
  vegetable 
  origin 
  . 
  

  

  The 
  author 
  describes 
  the 
  hypopial 
  or 
  migratory 
  nymph 
  of 
  the 
  above 
  

   three 
  species 
  of 
  Tyroglyphus, 
  in 
  which 
  stage 
  some 
  individuals 
  of 
  the 
  

   mites 
  survive 
  unfavourable 
  periods, 
  when 
  the 
  absence 
  of 
  food 
  leads 
  

   to 
  the 
  death 
  of 
  the 
  adults 
  and 
  larvae. 
  In 
  order 
  to 
  discover 
  the 
  presence 
  

   of 
  mites 
  in 
  flour, 
  the 
  author 
  suggests, 
  in 
  addition 
  to 
  the 
  usual 
  micro- 
  

   scopical 
  examination, 
  the 
  two 
  follow^ing 
  methods. 
  A 
  glass 
  full 
  of 
  

   flour 
  is 
  exposed 
  to 
  direct 
  light 
  and 
  the 
  presence 
  of 
  mites 
  will 
  be 
  demon- 
  

   strated 
  by 
  sinuous 
  lines, 
  marking 
  the 
  paths 
  of 
  those 
  which 
  are 
  trying 
  

   to 
  evade 
  the 
  light, 
  or 
  the 
  flour 
  may 
  be 
  arranged 
  in 
  small 
  heaps, 
  and 
  the 
  

   movements 
  of 
  the 
  mites 
  will 
  soon 
  bring 
  about 
  some 
  change 
  in 
  the 
  forms 
  

   of 
  them. 
  Mites 
  cannot 
  live 
  and 
  breed 
  in 
  dry 
  grain 
  or 
  flour 
  ; 
  they 
  can 
  be 
  

   destroyed 
  by 
  the 
  vapour 
  of 
  napthahne 
  in 
  from 
  9 
  to 
  20 
  hours 
  ; 
  the 
  same 
  

   results 
  can 
  also 
  be 
  obtained 
  with 
  carbon 
  bisulphide 
  or 
  by 
  a 
  temperature 
  

   of 
  135° 
  F. 
  Pediculoides 
  ventricosiis 
  can 
  only 
  be 
  successfully 
  destroyed 
  

   together 
  with 
  the 
  larvae 
  of 
  those 
  insects 
  on 
  which 
  it 
  breeds. 
  

  

  The 
  last 
  chapter 
  of 
  this 
  book 
  is 
  devoted 
  to 
  the 
  means 
  of 
  discovering 
  

   various 
  injurious 
  insects 
  in 
  grain 
  stores. 
  In 
  such 
  cases 
  it 
  is 
  advisable 
  

   to 
  examine 
  the 
  waste 
  found 
  in 
  the 
  grain, 
  such 
  as 
  parts 
  of 
  the 
  bodies 
  of 
  

   the 
  pests, 
  larval 
  skins, 
  and 
  the 
  excrement 
  of 
  various 
  insects, 
  and 
  

   although 
  these 
  studies 
  are 
  not 
  yet 
  concluded, 
  the 
  author 
  thinks 
  that 
  

   such 
  observations 
  may 
  prove 
  very 
  useful 
  in 
  identifying 
  the 
  exact 
  pests. 
  

   He 
  describes 
  and 
  figures 
  the 
  excrement 
  of 
  Bruchus 
  pisi, 
  Dermestes 
  

   lardarius, 
  Tenebrio 
  molitor, 
  Trachea 
  (Hadena) 
  basilinea, 
  Sitotroga 
  

   cerealella, 
  Calandra 
  granaria, 
  Sitodrepa 
  (Anohium) 
  panicea, 
  and 
  Tei:e- 
  

   broides 
  mauritanicus, 
  and 
  gives 
  details 
  which 
  allow 
  of 
  distinguishing 
  

   between 
  eleven 
  species 
  of 
  pests 
  according 
  to 
  their 
  excreta. 
  

  

  