The Elements of Insect Anatomy; An Outline for the Use of Students in the Entomological Laboratories of Cornell University and Leland Stanford Junior University - Tapa blanda

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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1895. Excerpt: ... CHAPTER II. THE EXTERNAL ANATOMY OF A LOCUST. (Melanoplus femur-rubrum.) Locusts or short-horned grasshoppers are excellent subjects to use in beginning the study of the external anatomy of insects. They are very common and are comparatively large; and the parts of the external skeleton in these insects are, as a rule, remarkably distinct. The species which has been selected as the basis of this outline is the red-legged locust, Melanoplus femur-rubrum, which is found in nearly all parts of the United States. Specimens of this insect, preserved in alcohol, will be furnished the student, who will be expected to verify carefully or to correct each statement made in the text. DIVISION OF THE BODY INTO REGIONS. The body of a locust is composed of a series of more or less ring-like segments. In the caudal part of the body the ring-like nature of the segments is obvious; in the cephalic part it is less so. These segments are grouped into three regions: head, thorax, and abdomen. Head.--The head is the first or cephalic of the three regions of the body. Apparently it consists of a single segment. Thorax.--The thorax is the second or intermediate region of the body. It is readily distinguished by its appendages; which are three pairs of legs and two pairs of wings. It consists of three segments; but as each segment is composed of several distinct pieces, it requires considerable study to trace the outlines of each segment. We will return to this subject later. Abdomen.--The abdomen is the third or caudal region of the body. The segments of which it is composed are more simple, distinct, and ring-like than those of the other regions. STRUCTURE OF THE BODY-WALL. Chitine.--In studying the anatomy of insects it is found that in the adult state the greater portion of ...