Regurgitation is the expulsion of material from the pharynx, or esophagus, usually characterized by the presence of undigested food or blood.
Flesh fly, from the family Sarcophagidae "blowing a bubble". One explanation for this behaviour is that it concentrates the fly's meal by the process of evaporation. The diet of the flesh fly is very high in water content. The fly regurgitates the liquid portion of the food, holds it while evaporation reduces the water content and the fly then swallows a much more concentrated meal without the water content. This continues until sufficient amount of liquid is left for the fly. –