Page:Insects - Their Ways and Means of Living.djvu/380

 which is the mouth cavity. The anterior wall of the bulb is ordinarily collapsed, but it can be lifted by a set of strong muscles (Mcl) arising on the front wall of the head (Clp). This bulb is the sucking pump of the fly, and it will be



seen that it is very similar to that of the cicada (Fig. 122, Pmp). In the fly, however, the liquid food is drawn up to the mouth through the labro-hypopharyngeal tube instead of through a channel between the appressed maxillae.

The mandibles of the horsefly (Fig. 170 B, Md) are long, bladelike appendages, very sharp pointed, thickened on