• 1
    This paper deals with a revision of the British species of the subfamily Aceosejinae together with a synonymic list of the species of the subfamily.
  • 2
    Keys are given for the separation of genera and species of the British aceosejines.
  • 3
    The following new synonymy is introduced:
  • (a) 
    Arctoseiulus Willmann and Arctotarseius Willmann are synonyms of Arctoseius Sig Thor.
  • (b) 
    Arctoseiodes Willmann is a synonym of Leioseius Berlese.
  • (c) 
    Seiopsis Berlese, Jordensia Oudemans and Blattilaelaps Womersley are synonyms of Proctolaelaps Berlese.
  • (d) 
    Garmania Nesbitt and Paragarmania Nesbitt are synonyms of Melichares Hering.
  • (e) 
    Arctoseiopsis Evans is a synonym of Iphidozercon Berlese.
  • (f) 
    Aceosejus Sellnick is a synonym of Lasioseius Berlese.
  • (g) 
    Lasioseius (L.)innumerabilis Berlese, Lasioseius alpinus Schweizer and Lasioseius ventritrichosus Schweizer are synonyms of Hypoaspis hypudaei Oudemans.
  • (h) 
    Typhlodromus domesticus Oudemans is a synonym of Melichares agilis Hering.
  • (i) 
    Typhlodromus tineivorus Oudemans, Blattisocius triodons Keegan and Lasioseius similis Schweizer are synonyms of Lasioseius (L.) tarsalis Berlese.
  • (j) 
    Lasioseius fimbriatus Halbert and Seiulus amboinensis Oudemans are synonyms of Lasioseius (L.) dentriticus Berlese.
  • (k) 
    Laelaps ligoniformis Michael is a synonym of Sejus muricatus C. L. Koch.
  • (l) 
    Arctoseius austriacus Willmann is a synonym of Gamasellus (Sessiluncus) eremitu Berlese.