STRUCTURE, ETC., OP COLEOPTERA. 13 



marking or development. It is the evident possibility 

 of a change, however slight, being effected, that gives so 

 much support to the prevalent theories as to the "origin 

 of species," discussions upon which most interesting 

 subject are not in the scope of the present work, and 

 would certainly not be of any use to a beginner, who 

 will find work enough in determining for himself points 

 upon which doctors do not disagree. One thing seems 

 sure, viz., that if changes do commence, they require 

 more than any man's lifetime to become permanent; 

 and the chances of any great alteration in the tempe- 

 rature or formation of our island are luckily too remote 

 to cause any apprehension on this score. With regard 

 to any departure from the natural laws of breeding, it 

 may be observed that hybrids, even of species most 

 closely allied, are of excessively rare occurrence, and are 

 never perpetuated ; indeed, most, if not all, of the re- 

 corded instances have occurred in confinement. 



A "genus" consists of an assemblage of such species, 

 usually somewhat alike in habits, as possess in common 

 either one well-defined structural character, or several of 

 a minor nature, unaccompanied by any radical points of 

 separation. 



In a similar way, subfamilies, families, tribes, sec- 

 tions, orders, and classes are constituted ; the points of 

 affinity in each become more and more remote as the 

 groups are wider in extent, but all uniting in some par- 

 ticular characters by which they may be known from 

 other portions of the animal kingdom. It is true that 

 all these relations and differences are purely artificial, 

 and may be upset at any moment by the discovery of 

 new combinations of forms, also that it is idle to expect 

 to tabulate creation correctly; nevertheless, the divisions 



