Peckia is the most species-rich necrophagous genus among the Neotropical sarcophagids, encompassing 67 species distributed in 5 subgenera. Recent phylogenetic studies have challenged the monophyly of this genus with regard to species of the genera Peckiamyia, Titanogrypa, and Villegasia, and the genera Engelimyia, Helicobia, Retrocitomyia, and Sarcophaga. These genera have variously been hypothesized as sister groups to Peckia, or genera closely related to it. We applied cladistic methods using both molecular and morphological data to study phylogenetic relationships of these mostly necrophagous taxa. All currently recognized species of Peckia were included in our analysis. Based on 116 morphological characters and sequences of five gene fragments, we corroborate the recent division of Peckia into five subgenera, and we argue that the reduction of the acrophallic median stylus is an autapomorphic condition supporting the clade (Peckia + (Lipoptilocnema (Helicobia + Sarcophaga))). Our analysis shows that Peckiamyia is sister to Retrocitomyia, and Titanogrypa is sister to Villegasia, which together with Engelimyia form lineages that emerge in a basal divergence with regard to the clade with no median stylus. Alternative homology interpretations of the median stylus were studied and tested in a phylogenetic context. The median stylus and other phallic homologies were revisited and redefined. All studied genera were found to be monophyletic.