Overview
Evaniids (hatchet wasps, ensign wasps) are solitary
parasitoids
of cockroach (Blattodea) oothecae (egg cases) and the adults can often be seen on flowers, tree trunks, or moving about on leaf litter. Although most Australian species were described in
Evania
, this genus does not naturally occur in the region, however, the cosmopolitan, introduced
E. appendigaster
, which parasitises the pest cockroach
Periplaneta americana
occurs in urban areas. Virtually all Australian species belong to one of two genera,
Szepligetella
and
Acanthinevania
, although
Brachygaster
has recently been recorded from north Queensland. Two, possibly three, additional genera occur in the region south of Wallace's Line as far as New Guinea but do not occur in Australia.
Description
They have a unique, very short, laterally compressed metasoma with a tubular petiole, so that the whole structure is not much longer than the thorax, if at all. They also have relatively short wings and elongate legs. When walking these wasps move their metasoma up and down, hence the common name of 'hatchet' or 'ensign' wasps.
Distribution
Evaniidae are a mainly tropical family but occur worldwide. About 455 species occur worldwide, with about 40 species described for Australia. Numerous species are also endemic to New Guinea and other south-west Pacific islands, but the family is absent from New Zealand.
Furhter information about the Evaniidae can be found in Deans & Huben 2003, Elliott 2005, Mason 1993 and Naumann 1991.