[2][3] The subfamily Tevenvirinae (synonym: Tequatrovirinae) is named after its type species Enterobacteria phage T4.

Members of this subfamily are morphologically indistinguishable and have moderately elongated heads of about 110 nanometers (nm) in length, 114 nm long tails with a collar, base plates with short spikes and six long kinked tail fibers.

The subfamily Spounavirinae are all virulent, broad-host range phages that infect members of the Bacillota.

[5] Their shared characteristics include an identical virion morphology, characterized by usually short contractile tails and all have genome sizes of approximately 45 kilobases.

It consists of a central tube, a contractile sheath, a collar, a base plate, six tail pins and six long fibers.

The injected DNA takes over the host cell's mechanisms for transcription and translation and begins to manufacture new viruses.

[2] Although Myoviruses are in general lytic, lacking the genes required to become lysogenic, a number of temperate species are known.

Because most Myoviridae are lytic, rather than temperate, phages, some researchers have investigated their use as a therapy for bacterial diseases in humans and other animals.