The first or outermost lobe, according to Wheeler, forms the optic ganglion of the larva and imago, while the second and third lobes. (_pc^2_, _pc^3_) ultimately form the bulk of the brain proper, or the protocerebral lobes. The second (primitively postoral) brain-segment or pair of ganglia gives origin to the antennæ, while the third brain, or premandibular (intercalary) segment, gives origin to a temporary embryonic pair of appendages found in Anurida and Campodea (the premandibular ganglia), and also to the nerves supplying the labrum. These three pairs of ganglia later on in embryonic life become preoral, the mouth moving backwards. The three pairs of primitive ganglia, behind, _i.e._ the mandibular and 1st and 2d maxillary ganglia, become fused together to form the subœsophageal ganglion, and which in larval and adult life is postoral. If the tongue (ligula, or hypopharynx) represents a distinct pair of appendages, then there are seven segments in the head. [Illustration: FIG. 246.—Section through head of a carabid, _Anopthalmus telkampfii_: _br_, brain; _fg_, frontal ganglion; _soe_, subœsophageal ganglion; _co_, commissure; _n_. _l_, nerve sending branches to the lingua (_l_); _mn_, maxillary nerve; _mx_, 1st maxilla; _mm_, maxillary muscle; _mx′_ 2d maxilla; _mt_, muscle of mentum; _le_, elevator muscle of the œsophagus; _l′_ of the clypeus, and a third beyond raising the labrum (_lbr_); _eph_, epipharynx; _g. g′_, salivary glands above; _g^2_, lingual gland below the œsophagus (_œ_); _m_, mouth; _pv_, proventriculus; _md_, mandible. ] The brain, then, supplies nerves to the compound and simple eyes, and to the antennæ, and gives origin to the sympathetic nerves; it is thus the seat of the senses, also of the insect’s mind, and coördinates the general movements of the body. [Illustration: FIG. 247.—Median longitudinal section through the head of _Blatta orientalis_. The nervous system of the head is drawn entire. _hyp_, hypopharynx; _os_. oral cavity; _lbr_, upper lip; _gf_, frontal ganglion; _g_, brain; _na_, root of the antennal nerve; _no_, root of the optic nerve; _ga_, anterior,—_gp_, posterior ganglion of the paired visceral nervous system; _œ_, œsophagus; _c_, œsophageal commissure; _usg_, infraœsophageal ganglia; _cc_, longitudinal commissure between this and the first thoracic ganglion; _sg_, common duct of the salivary glands; _lb_, labium (2d maxillæ); _nr_, recurrent nerve; _d_, nerve uniting the frontal ganglion with the œsophageal commissure; _e_, nerve from this commissure to the labrum; _f_, nerve from the infraœsophageal ganglion to the mandible, —_g_, to the 1st maxillæ, —_h_, to the lower lip (2d maxillæ).—After Hofer, from Lang. ] [Illustration: