Tachina grossa (Linnaeus, 1758) or known as “Giant tachinid fly”
Length: 14 to 20mm.
Family: Tachinidae.
Flight period: June to early September.
This is one of the largest species of fly and is the largest tachinid fly in Europe.
Tachina grossa is found throughout most of Western Europe, East to Asia and also into Mongolia.
A very distinctive fly being hairy with an all-black thorax and abdomen, in flight they can be easily be mistaken for a bumble bee because of this and their stout size.
Habitat: Mainly dry open meadows, woodland edges, peat land, heaths and gardens.
Adults feed on a variety of flowers for pollen and nectar. Like most other Tachinid flies, the female lays her eggs in other insect larvae which are mostly caterpillars; particularly the large hairy Lepidopteran caterpillars the fox moth (Macrothylacia rubi) and oak eggar moth (Lasiocampa Quercus). The flies larvae will develop by feeding inside the host caterpillar, and will continuously feed until the host eventually dies.
In Britain usually only one generation per year and in Southern Europe quite possibly two generations can be achieved, although this is not verified.