where the larvae prey on crustaceans, etc. (James et al., 1971). Twelve species are described from Australia, Tasmania and New Zealand, 4 from Europe and 4 from Japan. The genus was partially revised by Koch (1936).
Phucobius Sharp. The 7 species which have been described in this genus are similar to Cafius but lack spines on the anterior tibiae. They are confined to the Oriental Region except for one species from East Africa. They are all found on the seashore.
Orthidus Mulsant and Rey. Two species, O. cribratus Erichson from Europe and O. curtipennis Cameron from Singapore, both from the seashore, are the only species known in this genus. They are similar to Philonthus but have a single puncture on the disc of the pronotum whereas in Philonthus there may be either a row of punctures on each side of the disc or confused punctures throughout.
Philonthus Stephens contains several hundred moderate-sized-to-large (8-20 mm) insects, variously colored, very active and found in a large variety of habitats. A single species, P. nudus Sharp, is known from the seashore of Japan and the Pacific Northwest of North America. Several other species are found on the sandy beaches of Australia.
ECOLOGY AND DISTRIBUTION
Several distinctly different ecological zones are occupied by insects on the Pacific coast of North America which can be differentiated by the type of shore and the reach of the tide. The seashore staphylinid fauna falls into three main zones or ecological habitats with almost no overlapping of species between them. The three zones are determined by the type of shore: (1) mud flats which may be associated with large open bays or lagoons at the mouths of streams and rivers that are usually closed at least part of the year by sand bars, (2) sandy beaches which support the most varied insect fauna in Southern California, and (3) rocky headlands which support a fauna of insects capable of .living submerged in sea-water for long periods.
Each of the major ecological zones which supports insects can be readily divided into sub zones based on the reach of the tide. The sub zones fall into three categories: (1) the area which is wet by daily tides, (2) the area which is wet by only one or two high tides a month and (3) the berm of the beach which is reached by only the highest tides of the year. This sub zonation is most apparent on the sandy beaches where sub zone (1) contains fresh seaweed and such nocturnal staphylinids as Thinopinus, Pontamalota and Thinusa; sub zone (2) contains decaying seaweed and species of Cafius, Tarphiota and Aleochara and sub zone (3) has dry seaweed and no staphylinids but other Coleoptera (see Table 1). Among the marine Staphylinidae it is convenient to make a distinction between submarine and littoral species. Submarine species are those which not only tolerate submergence in seawater but actually