202 THE ESSEX NATURALIST
water-mites have been published. Soar listed twenty genera and fifty-
two species and to these can now be added Piona porripora, Arrhenurus
virens and A. bruzelii.
My own collecting was spread rather spasmodically over the years
1955 to 1958 in the Hatfield Peverel—Chelmsford area and was confined
to small ponds. The list is by no means exhaustive and there must be
many more unrecorded water-mites in the district.
HYDRACARINA
Limnocharae
Limnocharidae
Limnocharaes aquatica Latraille. Central Park, Chelmsford.
Hydryphantae
Hydryphantidae
Hydryphantes ruber de Greer. Common especially in temporary
ponds.
Hydrodromidae
Hydrodroma despiciens Muller. Common.
Pionae
Limnesidae
Limnesia fulgida Koch. Sand pits, Sandon and Boreham.
Limnesia maculata Muller. Sand pits, Central Park, Chelmsford, and
Hatfield Peverel.
Unionicolidae
Unionicola crassipes Muller. Hatfield Peverel.
Unionicola figularis Koch. Hatfield Peverel, Fairstead. Boreham.
Pionidae
Tiphys latipes Muller. Common in almost every pond.
Tiphys lutescens Herm. Common.
Tiphys ornatus Koch. Hatfield Peverel.
Piona carnea Koch. Common.
Piona conglobata Koch. Hatfield Peverel.
Piona rotunda Kramer. Common.
Piona obturbans Piersig. One only, Hatfield Peverel.
Piona porcipora Sig Thor. One only. Hatfield Peverel.
Arrhenurae
Arrhenuridae
Arrhenurus bruzelii Koen. Fairstead, Boreham.
Arrhenurus virens Neum. Fairstead (also nymphs).
Arrhenurus (Megaluracarus) caudatus Geer. Boreham.
Arrhenurus (Truncaturus) bifidicodulus Piersig. Fairstead.
Arrhenurus (Truncaturus) seccki Koen. Ingatestone.
Arrhenurus (Truncaturus) integrator Muller. Hatfield Peverel,
Boreham.