It's likely you're referring to a different structure, possibly:
* Subesophageal ganglion: This is a large ganglion in the ventral nerve cord of invertebrates, particularly insects. It controls the mouthparts, pharynx, and other anterior structures.
* Hypopharyngeal ganglion: This is a small ganglion found in some insects, located near the hypopharynx (the floor of the mouth). It controls the movements of the hypopharynx.
If you can provide more context about where you encountered the term "subpharyngeal ganglion", I may be able to give you a more precise answer.