62
THE ESSEX NATURALIST
Nineteen species in fifteen genera and six families are recorded.
All the families except the last two, Uropodidae and Canes-
triniidae, belong to the group Gamasides, which is part of the
division Mesostigmata of the sub-order Parasitiformes. The
family Uropodidae belongs to the group Uropodina of the Meso-
stigmata, and the family Canestriniidae belongs to the division
Acaridiae of the sub-order Sarcoptiformes.
All the specimens were collected by the author, except where
stated otherwise. The specimens have been presented to the
British Museum (Natural History).
Parasitidae Oudemans 1901
Parasitus fucorum (De Geer)
Deutonymphs on the bee Bombus terrestris (L.) at
Skipper's Island, Thorpe-le-Soken, on April 15-18, 1960.
Parasitus numismeticus Vitzthum
Deutonymphs on Bombus terrestris (L.) at Skipper's Island,
Thorpe-le-Soken, on April 15-18, 1960.
Parasitus sp.
The deutonymphs of the genus Parasitus cannot always be
identified to specific level at the present time. Deuto-
nymphs of this genus have been found on Bombus terrestris
(L.) at Goldings Hill, Loughton, on May 8, 1960; on the
wood mouse, Apodemus sylvaticus (L.), at Woodford Green
on August 3, 1960, and in a mouse's nest at Hales Wood,
Saffron Walden, on January 14, 1961.
Eugamasus loricatus (Wankel)
A female in the above mouse's nest.
Eugamasus sp.
A deutonymph on the beetle Hister unicolor L. at Woodford
Green in 1958.
Laelaptidae Berlese 1892
Myonyssus gigas Oudemans
Four females on a wood mouse at Woodford Green on May
8, 1960.
Eulaelaps stabularis (C. L. Koch)
Nine females on the above wood mouse; fourteen females
on a wood mouse at Woodford Green on August 3, 1960;
eleven females in a mouse's nest at Hales Wood, Saffron
Walden, on January 14, 1961.
Hirstionyssus arcuatus (C. L. Koch)
Two females on a wood mouse at Woodford Green on May
8, 1960.
Haemogamasus ambulans (Thorell)
Four females on the above wood mouse; nine females on a
wood mouse at Woodford Green on August 3, 1960. A
deutonymph was found on a wood mouse at Skipper's
Island, Thorpe-le-Soken, on April 15, 1960.