COLEOPTERA. 



Numerically the Coleoptera is far in the lead of all other groups. Half the 

 species of insects are beetles. The order contains about 40 per cent, of all 

 the species of animals and approximately a quarter of all living beings both 

 plants and animals. 



Historically the group stands intermediate between the older orders of 

 insects and the higher groups. Beetles are the culmination of the tendency 

 seen in the Orthoptera and Hemiptera to produce a fully armored insect, 

 a consummation reached only after the securing of complex metamorphosis 

 which was also the antecedent condition permitting the specializations of 

 structure characterizing the Diptera, Hymenopteha and Lepidoptera. 



Structurally the Coleoptera are distinguishable by the concurrent special- 

 ization of front wings and abdomen whereby the ventral portion of the latter 

 became enlarged joining with the former, enclosing a cavity into which the 

 spiracles open and within which the second pair of wings lie folded. Both 

 of these structures are absolutely distinctive of this order. 



Economically beetles fall into a very secondary rank. While many are 

 plant feeders, the great majority feed on decaying organic matter or are 

 predaceous. 



The classification of beetles was formerly largely based upon the number of 

 joints in the foot, more recently the significance of the venation has been 

 recognized. 



The system adopted in this book is the use of a series of superfamilies 

 as follows: — 



1. Carabina, 2. Tenebrionina, 3. Meloina, 4. Elaterina, 5. Cantharina, 6. 

 Clerina, 7. Hydrophylina, 8. Scarabaeina, 9. Curculionina, 10. Chrysomelina, 

 11. Coccinellina, 12. Nitidulina, 13. Dermestina, 14. Heterocerina, 15. Histerina, 

 16. Trichopterygina, 17. Silphina, 18 Staphylinina. 



The classification of Leconte and Horn,which has been generally followed 



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