200 CLASSIFICATION OF INSECTS. 



beetles between the moths and the butterflies ; neither 

 would any one place one of the moths or one of the butter- 

 flies, between the two beetles. 



Resemblances, in natural history, are not dependent on 

 the outward and obvious distinctions of size and colour, 

 but are to be traced in other characters; in economy, 

 habit, and structure. Economy comprises the acts of a 

 living being, as described in the First Book of this volume ; 

 structure is described in the Third Book ; and habit is the 

 external form and appearance ; in fact, the result of struc- 

 ture. In arranging, it is necessary to consult all these 

 characters, but principally structure, because, under all 

 circumstances, we gain some knowledge of this ; whereas, 

 habit may be occasionally altogether deformed, and econo- 

 my frequently altogether unknown: in structure, primary 

 variations occur in the systems of organs ', secondary vari- 

 ations in the details of each system. 



In all animals the bones, or organs of support, and the 

 covering of the surface of the body, as skin, hair, feathers, 

 or scales, afford the most ready characters by which to 

 distinguish different kinds of animals from each other: 

 now, in insects, we have seen that the organs of support 

 are on the surface of the body, and, therefore, present 

 greater facility to the describer. When the known animals 

 shall be so arranged that each one is placed nearest to the 

 one which it most resembles, and a series thus formed 

 from which none shall be excluded, then the arrangement 

 will be perfect, and the natural system will be discovered : 

 this has been the ultimate object of naturalists in all ages. 



In any abstract science, there is an evident advantage in 

 being able to determine the names of every object, or group 

 of objects ; and so to allude to either, in speaking or writing, 

 as that all persons possessing a moderate knowledge of the 

 science may at once form a definite idea of what is meant. 



