40 



FOREST ENTOMOLOGY. 



Fig. iO.— True vin^hii/hn tie. 

 II, folded ; h, unfolded. 



the tarsus, into four divisions — viz., Trimera, Teframera, Heteromera, 

 and Pentamera. This division is, of course, more or less arbitrary. 



The loings of beetles 

 are rather peculiar, as 

 what corresponds with 

 the wings of other in- 

 sects are the elytra 

 or wing-cases. These 

 have sometimes a very remarkable sculpturing, the use of which is 

 unknown. In repose, these two elytra are very well fitted together : 



the junction line is known 

 as the suture. The wings 

 proper, which correspond to 

 the ~ posterior pair of other 

 insects, present a very vari- 

 able structure, so far as the 

 arrangements of nerves and 

 cells are concerned. The 

 size and general structure 

 are compatible with the 

 folding up under the elytra 

 (fig. 40). In some forms 

 they are considered apter- 

 ous, but though in such 

 cases the wings are never 

 used, and the elytra some- 

 times soldered together, rudi- 

 mentary wings may often be 

 found. 



Throughout the respective 

 families various modifica- 

 tions of general anatomy 

 present themselves. In the 

 Rliyncliopliora or weevils, 

 for instance, there is a 

 prolongation of the mouth 

 called a rostrum, which, 

 true portion of the head, and in 



Fig. 41. — Typical beetle : . Pterosticlius vulgaris, I 

 (mule): upper side. (From Fowler's ' British Coleoi 

 tera. ') 



1. La brum. 



2. Labial palpus. 



3. Maxilla. 



4. Maxillary palpus. 



5. Mandible. 



6. Antenna. 



7. Front of head. 



8. Supra-orbital setce. 



9. Pronotuni, ordinarily 



called " thorax." 



10. Anterior lateral pore. 



11. Antjular pore. 



12. Scutelluni. 



13. Ba.sal fold of elytra. 



14. Scutellary stria. 



15. Suture of elytra. 



16. Sutural angle. 



17. Femur. 



18. Tibia. 



19. Spurs of tibia. 



20. Tarsus. 



21. Onychium and claws. 



22. Stigma. 



23. Pygidium. 



as Canon Fowler remarks, is 

 no sense a trunk. 



Classification. — Xotwithstanding the many works on Coleoptera, 



