Ultrastructural and molecular data are provided from a single adult female pentastomid opportunistically collected from a road-killed rattlesnake in Russell, KS. Ultrastructural data consisted of light and SEM microscopy of the pentastomid and its eggs, while molecular data consisted of partial 18S and 28S ribosomal sequences and a partial cytochrome c oxidase subunit 1 sequence from the same specimen used for SEM. Ultrastructural and molecular data support generic identification of the pentastomid as Porocephalus sp. These molecular data were also used with previously published pentastomid sequence data for a concatenated phylogenetic analysis, which support the current, morphology-based taxonomic placement of the genus. Keywords: Pentastomida; Molecular Identification; Egg Structure; Tongue Worms; Porocephalus crotali