Insěcta, s

pl. [Pl. of Lat. insectum an insect, from insect us, pa. par. of inseco =tocut into, to cut up, because the body seems cut into three leading segments-the head, the thorax, and the abdomen.] 1. Entom .: Insects; a cla of Annulosa, division Arthropod a. Formerly it was made to include, among other animals, the centipedes and spiders. Now these are made distinct cla es, and the Insect a confined to those arthropodous animals which have three pairs of legs; these are affixed to the thorax, which is distinctly separated from the head and the abdomen. There are compound and simple eyes. In the highest orders there are four wings; in another order, Diptera, but two; and in several more the wings are rudimentary or totally absent. There is one pair of antenne. The respiration is by tracheæ. Of the thirteen segments, of which a typical insect consists, one constitutes the head, three the thorax, and nine the abdomen. The cutaneous skeleton is composed of chitine. There is generally a more or le complete metamorphosis. Insects exist in all countries. The species existing may be half a million, those known more than 200,000. Most of them are confined to particular regions: thus the insects of India and China are mostly different from those of Europe; so are those of North America, Green land only excepted. Some IMG:content-1709.png:[blocks in formation] 1, 1. The Antennæ. 2, 2. The Maxillary palpi. 3. The Mandibles, between and behind which is the Labrum, or Upperlip. 4. The Head. 5. The Thorax. 6. The Scutellum. 7. The Elytra, covering the Abdomen. 8. The Femur, or Thigh. 9. The Tibia, or shank. 10. The Tarsi, or Foot. 11. The Claws. insects, however, like the Painted Lady Butterfly (Cynthia cardui ), are widely diffused over the world. Insects exert a powerful influence in fertilizing plants. Tiny as they are, some of them may become formidable foes to man. Linnæus founded his cla ification on the presence or absence of wings, and, in the former case, on their number and structure. He divided his Insect a into eight orders: Coleoptera, Hemipter a, Lepidoptera, Neuroptera, Hymenoptera, Diptera, and Aptera. Among the Aptera were included Crustaceans, as well as Spiders and Myriapods. Latreille, followed by De Geer, introduced another order, named Orthoptera by Olivier. Latreille adopted it and ultimately excluding the Crustaceans from Aptera, broke that order in to four: Myriapod a, Thysanura, Paras it a, and Suctoria. He adopted Kirby's order Strepsiptera, calling it Rhipiptera. Stephens' division was into two sub-cla es: MandibulataOrders, Coleoptera, Derm apter a, Orthoptera, Neuroptera, and Trichoptera; an 1 Haustellata-Orders, Lepidoptera, Diptera, Homaloptera, Aphaniptera, Aptera, Hemipter a, and Homoptera. Bur meister di vided insects into totwo sub-cla es, Ar which the metamorphosis is complete, and Metabola, in which it is not so. Under the former are ranked the orders Hemipter a, Orthoptera, and Dicty opter a; and under the latter, Neuroptera, Diptera, Lepidoptera, Hymenoptera, and Coleoptera. Profe or Huxley considers the orders Coleoptera, Hymenoptera, Lepidoptera, Diptera and Hemipter a well established; the proper grouping of Strepsiptera, Trichoptera, Neuroptera, and Orthoptera, a matter of doubt; and the Physopoda, Thysanıza, and Mallophaga, not fitting well into any of the other a emblages. The Myriapod a and Arachnid a he makes distinct cla es from Insect a. The cla ification now commonly adopted divides insects thus: Ametabola, in Sub-cla I., Ametabola: (1) Anoplura, (2) Mallophaga, (3) Collembola, (4) Thysanura. Sub-cla II., Hem i meta bola: (1) Hemipter a or Rhynchota, (2) Orthoptera, (3) Neuroptera. Sub-cla III., Holometabola: (1) Aphaniptera, (2) Diptera, (3) Lepidoptera, (4) Hymenoptera, (5) Strepsiptera, (6) Coleoptera. 2. Palæont .: The oldest known insects are from the Devonian rocks of this country. They seem to have belonged to the Neuroptera. This order, with the Coleoptera and Orthoptera, exists in the Carboniferous, Hymenoptera and Lepidoptera in the Secondary formation, and nearly all the known orders in the Tertiary. *In-sec-ta-tion, s. [Lat. insectatio , from insec tatus , pa. par. of in sector to follow, to pursue.] The act of following or pursuing; pursuit, persecution. for "I can no further go, but put all in the handes of him stirred by mine owne conscience (without in sect at i on , or reproche laieng to any other man)."-Sir T. Moore: Workes , p. 1,431. *In-sec-tā-tör, s. [Latin, from insect at us , pa. par. of in sector .] A persecutor.