Thrinaphe is a genus of millipede in the family Xystodesmidae with a single described species.

[2] The genus is found in the Cascade mountains on the Washington/Oregon border as well as down into the Willamette Valley.

[2] Thrinaphe is a robust Xystodesmid with an overall brown ground color and slight blueish tinge to the tergites.

[2] The paranota arise very low on the tergites and are also strongly depressed, giving the millipede a cylindrical appearance from above.

[1] The name Trinaphe is a reference to the three-branched telopodite of the gonopod and the similarity to Harpaphe[2] Thrinaphe contains the following species: