Structure and classification of insects . STYLOPS ATEREIMA. THE THORAX OR TRUNK. The thorax of the insect is the centre of motion, andthe main support and prop of the two other primary-sections of the body, of which the headY^ the principalseat of the organs of sensation, and the abdomen of di-gestion, respiration and generation. It may be observed in relation to its substance^ generalform^ proportions, composition or jyarts, internal anat-omy and members, and of these it will be spoken of hereonly in relation to its composition or parts, and mem-bers, wings and legs—its internal anatomy
Structure and classification of insects . STYLOPS ATEREIMA. THE THORAX OR TRUNK. The thorax of the insect is the centre of motion, andthe main support and prop of the two other primary-sections of the body, of which the headY^ the principalseat of the organs of sensation, and the abdomen of di-gestion, respiration and generation. It may be observed in relation to its substance^ generalform^ proportions, composition or jyarts, internal anat-omy and members, and of these it will be spoken of hereonly in relation to its composition or parts, and mem-bers, wings and legs—its internal anatomy furnishinga subject for distinct consideration, and its substance,form and proportions are points that may be readily ob-served by the student without any assistance. Composition or Parts.—The thorax is composed of 48 THE THORAX Uli TiiUXK. three primary rings, the first, or the one next the headhaving the name of prothoraXy the second mesothorax^. MTEMICO, ONE OF THE SOCIAL ANTS. and the third metathorax; in most insects, however,there are apparent but two segments, the prothorax con-stituting the first and the mesothorax and metathoraxthe second; to the former are attached the first pair oflegs, often denominated the arms, and to the latterthe remaining two pairs of legs, or legs proper, andthe one or two pairs of wings. Each of these three sections might be considered inrelation to a number of special parts, but we will desig-nate only those of the prothorax, and then proceed to aconsideration of their appendages, the legs and wings. The prothorax consist commonly of two pieces; theshield or upper part, and the era or under part, a con-tinuation of the shield under the body. The shield hasseveral plates or portions termed the apex, the part nextthe head, the base, that next the abdomen, the border orlimb, and the disk or central part. Omitting the details of the second and third rings ofthe thorax (mesothorax and metathorax),
Size: 2256px × 1107px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1870, booksubjectinsects, bookyear1872
