324 



ZOOLOGY 



a tihia, and the five-jointed tarsus, the distal joint of which 

 carries two claws. 



The dorsal part of the prothorax forms a broad shield, the 

 pronotum. The mesothorax bears dorsally the anterior pair of 

 wings, which are horny and hard, and are termed elytra; they 

 afford a protective covering to the membranous posterior wings, 

 and to the abdomen as far as the eighth segment. The meta- 

 thoracic wings are membranous, they stretch out at right angles 

 to the body and are used for flight, at other times they are 

 folded under the elytra. The superficies of these wings is 

 divided into a number of small areas or cells by the presence 

 of chitinous tubules, in which tracheae and nerves ramify ; these 

 " cells " are of great importance in Insect classification. 



The third division of the body, the abdomen, is by far the 

 bulkiest ; it comprises eight segments, each composed of a 



Fig. 186. — A male Melolontha 

 vulgaris, seen from above, 

 slightly enlarged. After 

 Vogt and Yung. 



1. Head, stretched forward. 



2. Prothorax. 



3. Mesothorax, scutelltun. 



4. Metathorax. 



5. Ahdomen. 



6. Anterior wing (elytron) of 

 right side, turned for- 

 ward. 



7. Posterior ■wing of right side, 

 expanded. 



8. Maxillary palps. 



9. Femvir of third right leg. 



10. Tibia of third right leg. 



11. Tarsus of third right leg. 



dorsal plate, the tergum or 7iotum,a.Tid a ventral plate, the sternum, 

 the soft integument which connects the sides of these successive 

 plates is pierced by the apertures of the six pairs of abdominal 

 stigmata. The eighth tergum is prolonged into a long bluntly 

 pointed process, which overhangs the openings of the alimentary 

 canal and generative organs (Fig, 186). 



The alimentary canal of the cockchafer is about six times 

 as long as the body, and is therefore necessarily thrown into 

 loops more or less coiled (Fig. 1 8 7). This is unusual amongst 

 Arthropods (though common in Insects), in which the digestive 

 tract is as a rule a straight tube, running directly between 



