﻿119 
  

  

  PRELIMINARY 
  LIST 
  OF 
  THE 
  ACARI 
  OCCURRING 
  ON 
  THE 
  BROWN 
  RAT 
  

  

  (MUS 
  NORVEGICUS) 
  IN 
  GREAT 
  BRITAIN, 
  WITH 
  THE 
  DESCRIPTION 
  OF 
  A 
  

  

  NEW 
  SPECIES 
  (HAEMOGAMASUS 
  OUDEMANSI). 
  

  

  By 
  Stanley 
  Hirst. 
  

  

  (Published 
  by 
  permission 
  of 
  the 
  Trustees 
  of 
  the 
  British 
  Museum). 
  

  

  Plates 
  XIV-XVI. 
  

  

  The 
  English 
  specimens 
  listed 
  below 
  were 
  captured 
  on 
  wild 
  examples 
  of 
  the 
  brown 
  

  

  rat 
  by 
  the 
  author, 
  and 
  those 
  from 
  Scotland 
  by 
  Waterston. 
  Several 
  of 
  these 
  mites 
  

  

  have 
  already 
  been 
  recorded 
  by 
  Dr. 
  A. 
  C. 
  Oudemans 
  and 
  other 
  authors 
  as 
  occurring 
  

  

  on 
  this 
  host. 
  Only 
  three 
  of 
  the 
  species 
  (Laelaps 
  echidninus, 
  Notoedres 
  muris 
  and 
  

  

  Myobia 
  ensifera) 
  can 
  be 
  regarded 
  with 
  certainty 
  as 
  being 
  practically 
  restricted 
  to 
  

  

  Mus 
  norvegicus, 
  but 
  this 
  is 
  possibly 
  also 
  the 
  case 
  with 
  Haemogamasus 
  oudemansi, 
  

  

  which 
  so 
  far 
  has 
  only 
  been 
  found 
  on 
  this 
  host. 
  The 
  other 
  species 
  are 
  frequently 
  

  

  found 
  on 
  other 
  mammals 
  or 
  in 
  their 
  nests, 
  especially 
  in 
  that 
  of 
  the 
  mole 
  (see 
  

  

  Oudemans, 
  Acarologisches 
  aus 
  Maulwurfsnestern, 
  Arch. 
  Naturg. 
  Berlin, 
  1913). 
  

  

  My 
  best 
  thanks 
  are 
  due 
  to 
  Dr. 
  A. 
  C. 
  Oudemans, 
  of 
  Arnhem, 
  for 
  the 
  excellent 
  draw- 
  

   ings 
  of 
  Haemogamasus 
  oudemansi 
  which 
  he 
  has 
  very 
  kindly 
  prepared 
  and 
  given 
  to 
  

   me. 
  I 
  must 
  also 
  thank 
  Miss 
  Gertrude 
  Woodward 
  for 
  her 
  careful 
  drawings 
  of 
  the 
  other 
  

   species. 
  

  

  Family 
  Gamasidae. 
  

   (1.) 
  Laelaps 
  echidninus, 
  Berl. 
  (text-figs. 
  1-3.) 
  

   Laelaps 
  echidninus, 
  Berlese, 
  Acari, 
  etc. 
  Ital., 
  fasc. 
  xxxix, 
  no. 
  1, 
  figs. 
  1-4 
  (1887) 
  ; 
  

   Miller, 
  Treas. 
  Dept. 
  Pub. 
  Hlth. 
  Mar. 
  Hosp. 
  Serv. 
  Hyg. 
  Lab., 
  Bull. 
  no. 
  46 
  

   (1908) 
  ; 
  Hirst, 
  Bull. 
  Ent. 
  Res., 
  iv, 
  pp. 
  123 
  and 
  124, 
  figs. 
  3 
  and 
  4 
  (1913). 
  

   Protonymph 
  (fig. 
  1). 
  Three 
  pairs 
  of 
  fairly 
  conspicuous 
  little 
  shields 
  and 
  also 
  a 
  pair 
  

   of 
  very 
  minute 
  platelets 
  are 
  present 
  between 
  the 
  two 
  main 
  shields 
  of 
  the 
  dorsal 
  surface 
  

  

  \ 
  / 
  i 
  

  

  Fig. 
  1. 
  Dorsal 
  and 
  ventral 
  view 
  of 
  protonymph 
  of 
  Laelaps 
  echidninus, 
  Berl. 
  

  

  