Economic entomology for the farmer Economic entomology for the farmer and fruit-grower economicentomolo01smit Year: 1906 STRUCTURE AND CLASSIFICATION. 15 or upper jaws are distinct and prominent. They work horizon- tally, from side to side, instead of vertically, or up and down, as is the case in the higher animals, and their form and general shape often furnish an indication to the character of the species,—that is, whether it is predace- ous, living upon ani- Fig. 3. mal food, or whether it is phytophagous, feeding upon plant tissue. This alone, in some orders, sufifices to tell us whether
Economic entomology for the farmer Economic entomology for the farmer and fruit-grower economicentomolo01smit Year: 1906 STRUCTURE AND CLASSIFICATION. 15 or upper jaws are distinct and prominent. They work horizon- tally, from side to side, instead of vertically, or up and down, as is the case in the higher animals, and their form and general shape often furnish an indication to the character of the species,—that is, whether it is predace- ous, living upon ani- Fig. 3. mal food, or whether it is phytophagous, feeding upon plant tissue. This alone, in some orders, sufifices to tell us whether we have to deal with a friend or an enemy. If the jaws are rather long, sharp-pointed, with slender, sharp teeth on the inner side (Fig- 3, c, d), it may be safely classed as predaceous ; if they are broad, stout, con- cave within, the edges meeting broadly, even if toothed, or if they are gouge-shaped (Fig. 3, a, e), we can say with great confi- dence that the species feed upon vegetable tissue. Of course some uncertainty may result in intermediate types (Fig. 3, b) ; but the rule holds good generally, and where it leaves a doubt, some other character will readily determine the question. Forming the front of the mouth and covering the base of the mandibles is the upper lip, or labrum ; on the inner side of which there is usually a sensitive structure, the epipharynx, which con- tains the organs of taste, and corresponds as nearly as may be to the palate in higher animals. It has no special function in feed- ing, and often seems to form part of the front of the head itself Below the mandibles we have a second pair of jaws or 7naxill<z, Mouth parts of a mandibulate insect: different types of mandibles at a, b, c, d, e; /, the labrum-epipharynx ; g, h, types of maxillae ; the cardo at c; stipes, st; sub- ^/ galea as marked ; palpus bearer,/yr; palpus atnixp; lacinia at/ac,- and digitus at rf/]?-; «, the labium with sub-mentum, sm, mentum, tn, ligula, lig, para- gl
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