Forest entomology . general structure of each divisionand its respective appendages. This isalso very important from a biologicalpoint of view, for undoubtedly if insectanatomy be generally considered, it willbe found that there is not a differencein structure of the various orders, butsimply a modification of similar anatomy of the mouth parts of the beetle affords a very goodcase in point. Head.—Viewed from the top side, the eyes and antennas are themost salient features. Fig. 39 shows all the respective parts : I is thelabrum or upper lip, which can be seen from the upper side. Ac
Forest entomology . general structure of each divisionand its respective appendages. This isalso very important from a biologicalpoint of view, for undoubtedly if insectanatomy be generally considered, it willbe found that there is not a differencein structure of the various orders, butsimply a modification of similar anatomy of the mouth parts of the beetle affords a very goodcase in point. Head.—Viewed from the top side, the eyes and antennas are themost salient features. Fig. 39 shows all the respective parts : I is thelabrum or upper lip, which can be seen from the upper side. Ac-cording to writers on beetle anatomy, the portion immediately behindthis, b, is called the clypeus, c, or shield of the mouth, and behindthis is the head proper, b. In the Bhynchophora the head is prolonged into a snout, calledthe rostrum, which is a true portion of the head, and in no sense a 1 For full particulars of structure, the student is advised to consult Fowlers Coleoptera of the British Islands, vol. Fig. 39.—Head of Cicindela(magnified). a, with jaws closed ; b, with jawsopen; I, labrum; c, clypeus.(From Fowlers British Coleop-tera. ) COLEOPTERA. 39 trunk. On each side of the rostrum there is usually a groove intowhich the long first joint of the antennae generally lies when theinsect is at rest. These grooves are called scrobes, and are usefulcharacters in the determination of the Rhynchophora. The anteriorportion of the head is called the forehead or front, and the centralportion the vertex. The antennce are very variable in the Coleoptera, and in manycases afford good points for the discrimination of genera andspecies. The eyes are generally very prominent. The thorax, of course, can be easily recognised, but it must beremembered that the transverse division line as seen from the uppersurface does not represent the length of this segment, inasmuch asit projects on the under surface and extends under the other words, the under side of the thorax
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