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 

 metathorax, is a good deal larger than the mesothorax. It 

 carries the membranous wings which are employed in flying. 

 When the wings are extended, the terga, or dorsal plates. 



Fig. 19. 

 Male cockchafer. 



