Exorista mella is a tachinid fly of the genus Ezorista within the family Tachinidae of the order Diptera.

E. mella is a parasitoid fly, a polyphagous generalist which parasitizes a variety of hosts.

[clarification needed] Physical characteristics include having a stigmal plate that is not elevated like their protuberance, as well as a sternopleuron pertaining to the thorax on the lateral side with three bristles.

[10] The earliest recorded viable eggs in a study were from females 48 to 72 hours old, which had immediately mated after emerging.

[13] Even without having mated, newly emerged females have also been documented to be able to oviposit infertile and consequently unviable eggs.

[10] Female E. mella flies extend their ovipositor onto the surface of their host of choice to lay their hard-shelled eggs.

It has been recorded to parasitize the following families of caterpillars: Arctiidae, Noctuidae, Notodontidae, Lymantriidae, and Lasiocampidae.

[8] E. mella has also been noted by one study to be one of the core three parasitoids to account for the mortality of a variety of caterpillars.

[15] Some of these hosts, such as the Apantesis incorrupta moth, have been observed to be able to fight back against parasitism by E. mella through a particular diet of plants, as well as surviving through adulthood.

[14] Another experiment looked into the potential of E. mella flies as biocontrol agents in agriculture for certain pests.

[10] Both sexes have been observed to show a decline in their ability to produce viable offspring after a certain amount of time after emergence.