. Injurious and useful insects; an introduction to the study of economic entomology. Insects; Beneficial insects; Insect pests. 26 INJURIOUS AND USEFUL INSECTS few hours in a tin box lined with strips of wet blotting-paper, when the various joints and membranes become almost as flex- ible as in a fresh insect. Place a cockchafer before you with the back upwards, and note the parts which are visible in this position. These are the head, the prothorax, the elytra or wing-covers, the scutel- lum, a small, black, triangular plate, appearing between the wing-covers in front, and, lastly, the two hi
. Injurious and useful insects; an introduction to the study of economic entomology. Insects; Beneficial insects; Insect pests. 26 INJURIOUS AND USEFUL INSECTS few hours in a tin box lined with strips of wet blotting-paper, when the various joints and membranes become almost as flex- ible as in a fresh insect. Place a cockchafer before you with the back upwards, and note the parts which are visible in this position. These are the head, the prothorax, the elytra or wing-covers, the scutel- lum, a small, black, triangular plate, appearing between the wing-covers in front, and, lastly, the two hindmost abdominal segments, which are the only ones not hidden by the wing-covers. Note that the last of these is curved down- wards, and tapers towards its extremity. It is characteristic of beetles that the wing-covers, if well developed, meet along a straight line (the suture), which runs down the middle of the back. The prothorax in beetles is, as here, large and toler- ably mobile. Now carefully extend the wing-covers. There will be seen beneath them a pair of gauzy wings, folded up into a small space. By gently pulling out the wing with a pair of fine forceps, it can be expanded as in flight, and we shall then observe how it is folded up when at rest. It is folded fan-wise, and also trans- versely. In some beetles the wings are crumpled up in so elaborate a fashion that it takes them a minute or two either to expand them, or to pack them neatly within the wing-covers. When both the wing-covers and the wings are fully extended, all three rings of the thorax will become distinctly visible. The first ring or prothorax we have already seen. Behind this comes the mesothorax, which is by comparison short. As in most beetles, the only exposed part of the dorsal surface of the mesothorax is a triangular or rounded plate, the scutellum, which is accurately fitted in between the bases of the wing-covers; the fore part of the mesothorax is hidden by the prothorax. The third ring, or
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectinsects, bookyear1902
