. Elements of zoology, or, Natural history of animals / ed. by Reese. Zoology. 302 ZOOLOGY. 484. In other instances, an entirely different modifica- tion of the same parts may be observed. Thus, in the Diptera, to which the gnat, horse-fly, and other blood- sucking insects belong, we find a sort of proboscis formed by a prolongation of the lower lip ; and between its base and the upper lip, there are five lancets, with sharp cut- ting points or edges, of which the upper pair represents the mandibles, the lower ones the maxillae, while the middle one is the tongue. 485. The head of the per
. Elements of zoology, or, Natural history of animals / ed. by Reese. Zoology. 302 ZOOLOGY. 484. In other instances, an entirely different modifica- tion of the same parts may be observed. Thus, in the Diptera, to which the gnat, horse-fly, and other blood- sucking insects belong, we find a sort of proboscis formed by a prolongation of the lower lip ; and between its base and the upper lip, there are five lancets, with sharp cut- ting points or edges, of which the upper pair represents the mandibles, the lower ones the maxillae, while the middle one is the tongue. 485. The head of the perfect insect is usually furnished with three pairs of jointed appendages, all of which are probably instruments of sensation. The first of these are termed antennae ; they are affixed to the sides of the head, and usually between the eyes and the mouth. The num- ber of joints in them, and the forms they present, vary in the different tribes of insects; as also does their size, within very wide limits. Sometimes they are three or four times as long as the whole body, and sometimes they are scarcely to be per- ceived. Sometimes they are simple thread-like Or- Variously formed Antennae. gans, gradually tapering from the base to the point; some- times they swell out towards the extremity, and often pos- sess side branches or appendages of various forms. These different characters are extremely useful in classification. The palpi, or feelers, are organs which are not dissimilar in general character, but are usually of much smaller size, consisting of seldom more than six joints ; of these, one pair is attached to the maxillae, and the other to the labium, and they are called maxillary and labial palpi respec- tively. 4w(j. The uses of these organs are involved in some 533. What of the proboscis of blood-sucking insects? 53 t. What appendages of the head are mentioned ?. Please note that these images are extracted from scanned page images that may have been digitally enhanced for read
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