λ-like viruses
T1-like viruses
T5-like viruses
c2-like viruses
L5-like viruses
ψM1-like viruses
φC31-like viruses
N15-like viruses Siphoviridae are a family of double-stranded DNA viruses infecting only bacteria that are characterized by a long non-contractile tail and an isometric capsid (morphotype B1) or a prolate capsid (morphotype B2).

The Siphoviridae viruses have a capsid with a diameter of about 55-60 nm and a long tail that can reach up to 570 nm. Their double-stranded DNA is linear. This family includes the phage λ, the phage χ and the phage φ80 .

The following genera are included here:

• Genus λ-like viruses ; type species: Enterobacteria phage λ
• Genus T1-like viruses ; type species: Enterobacteria phage T1
• Genus T5-like viruses ; type species: Enterobacteria phage T5
• Genus c2-like viruses ; type species: Lactococcus phage c2
• Genus L5-like viruses ; type species: Mycobacterium phage L5
• Genus ψM1-like viruses ; type species: Methanobacterium ψM1
• Genus φC31-like viruses ; type species: Streptomyces phage φC31
• Genus N15-like viruses ; type species: Enterobacteria phage N15