ENTOMOLOGY

(Yunanca köken — orijinale bakınız.) The science of insects: the history of the organization, habits, properties, and cla ification of those articulated animals which are distinguished by the presence of antenna: and of breathing organs, composed of ramified tracheae with or without air-sacs. The name insect, from its etymological signification of an animal insected or divided into sections, is applicable to the greater part of the Articulate sub-kingdom, but is now restricted to those species characterized as above. The presence of highly developed organs for breathing air, together with peculiar and complex organs of sensation, is a ociated, as might be expected, with active powers of locomotion; and most insects, besides having articulated members for terrestrial progre ion, for leaping or climbing, swimming or diving, are endowed with wings, and are capable of rapid and extensive flight. The power of traversing space is given in greater fulne and perfection to the cla of insects than to any other created beings on our planet. A peculiar condition of the breathing organs, and a peculiar animal ti ue (chitine), which combines great strength, elasticity, and levity, coexist in insects, and in insects only. If, therefore, the highest of living created animals contain the characteristic structures of all lower forms, as some transcendental anatomists a ume, then man is not the acme or apotheosis of animal organization; for neither anastomosing tracheae nor a particle of chitine is present in his system; nor does he po e a thousandth part of the locomotive energies of certain insects. Those insects which have more than six articulated legs, and have the segments of the trunk free, without distinction of thorax and abdomen, which undergo no other metamorphosis than acquiring an increased number of segments after exclusion from the egg, and which lastly po e neither compound eyes nor wings, are separated by some zoologists as a distinct cla , under the name Myriapod a, which see. In the Hexapod insects, the body is divided into a head, thorax, and abdomen; the head supports a pair of antenna:, and contains a pair of compound, and often also simple eyes; the mouth is provided with a labium, labrum, mandibular, and maxillae; the labium and maxilla: also support peculiar feeling organs, called palpi. Sometimes these parts of the mouth, which are termed collectively trophi, or oral organs, are distinct, and adapted to mastication: the insects'mary division thus of characterized the cla termedconstituteMandibulata.an extensiveThosepriinsects in which the trophi are so modified as to form an instrument of suction are included in the primary division called Haustellata. The Hexapod insects were divided by Linna:us into the following orders:— 1. Coleoptera. Wings four, the upper hair hard, with a straight suture. Ex.: Beetles and earwigs. 2. TTemiptera. Wings four, the upper pair moderately hard and incumbent. Ex.: Bugs, locusts, tree-hoppers, plant-lice, < . 3. Lepidoptera. Wings four, covered with scales. Ex.: Moths and butterflies. 4. Neurnptera. Wings four, membranaceous; anus unarmed. Ex.: Dragon-flies, May -flies, <fce. 5. Hynmioptera. Wings four, membranaceous; anus aculeate. Ex.: Bees, ants, saw-flies, . 6. Diptera. Wings two; halteres two, in place of the posterior wings. Ex.: Flies. 7. Aptera. Wings none. In this order Linnaeus included not only true Apterous insects, as fleas, but also centipedes, spiders, crabs, lobsters, .; or the articulate animals now forming the cla es Myriapod a, Arachnid a, and Crustacea. There is not, perhaps, any cla of the animal kingdom which has been the subject of more numerous and various attempts at cla ification than that of insects. We have just seen that I,inneeus adopted the locomotive system as the basis of his method Fabric i us, his pupil, proposed a system founded on modifications of the structure of the mouth. I.a treille endeavoured to form a natural cla ification of those most numerous animals from a consideration of their entire organization. His latest system is as follows:— Sub-cla I. Aptera. No wings; simple eyes in most. A. No metamorphosis, but simple moulting, without a season of torpidity; mouth in some a simple sucker, in others mandibulate. 40G [s. 420]