Fig. 14.—Top of Head. ep, epicranial plate; oc, eye; ge, gena. × 10.
The top and back of the head are defended by the two epicranial plates, which meet along the middle line, but diverge widely as they descend upon the posterior surface, thus enclosing a large opening, the occipital foramen. Beyond the foramen, they pass still further downwards, their inner edges receding in a sharp curve from the vertical line, and end below in cavities for the articulation of the mandibular condyles.[43]
The sides of the head are completed by the eyes and the genæ. The large compound eye is bounded above by the epicranium; in front by a narrow band which connects the epicranium with the clypeus; behind, by the gena. The gena passes downwards between the eye and the epicranial plate, then curves forwards beneath the eye, and just appears upon the front of the face, being loosely connected at this point with the clypeus. Its lower edge overlaps the base of the mandible, and encloses the extensor mandibulæ.
Fig. 15.—Side of Head. oc, eye; ge, gena; mn, mandible. × 10.
Fig. 16.—Back of Head. ca, cardo; st, stipes; ga, galea; la, lacinia; pa, palp; sm, submentum; m, mentum; pg, paraglossa. × 10.