Diphyus is a genus of parasitoid wasps belonging to the family Ichneumonidae.

The genus was first described in 1890 by Joseph Kriechbaumer. (In the contents, the new genus is listed as Diphyes, a genus name which had already been used (1817) in the animal kingdom for a cnidarian genus, but in the text he described the genus Diphyus. He immediately follows this description with a description of Diphyes tricolor, which he references later in 1891 with the name Diphyus tricolor. Thus, the species is Diphyus tricolor.

The genus has almost an cosmopolitan distribution.

Some species:

• Diphyus akaashii (Uchida, 1955)

• Diphyus adventor (Berthoumieu, 1892)
• Diphyus albicoxalis (Uchida, 1927)
• Diphyus duodecimguttorius (Uchida, 1955)
• Diphyus higebutonis (Uchida, 1955)
• Diphyus iwatai (Uchida, 1955)
• Diphyus palliatorius (Gravenhorst, 1829)
• Diphyus quadripunctorius
• Diphyus restitutor (Wesmael, 1859)
• Diphyus salicatorius (Gravenhorst, 1820)
• Diphyus suigensis (Uchida, 1927)
• Diphyus tricolor (Kim, 1955) Kriechbaumer, 1890
• Diphyus temmazanensis (Uchida, 1955)

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