The original description of Mediorhynchus gallinarum (Bhalerao, 1937) and subsequent descriptions by other observers were riddled with errors and misinterpretations. The present collection of many specimens of M. gallinarum from chickens, Gallus gallus L., in Indonesia provided the opportunity to describe the Indonesian population, report the full range of variation in morphometric characteristics, especially proboscis armature, correct a few misconceptions, and obtain scanning electron microscopy documentation of previously unreported structures including features of the proboscis and hooks, the epidermis, sensory pores, bursa, and egg topography. Additionally, Indonesia is a new locality record for M. gallinarum.