why is the tongue in cockroach called hypopharynx?

Hypopharynx  in humans is the bottom part of pharynx. It connects throat to the oesophagus. 

But in cockroach, hypophaynx is a small, cylindrical mouthpart or extended part of pharynx, sand witched between first maxillae and covered by labrum and labium on dorsal and ventral sides respectively. It behaves like tongue as it is a median tongue like chitinous structure with two pointed lobes that also bears several sensory setae on its free end. It hangs in the pre oral cavity. It receives saliva from  the salivary duct.