INTRODUCTORY REMARKS. 3g 



per, for in this consists the essence of the plant. 

 To nourish and bring this to maturity the root 

 sends its fibres downwards, the stem shoots up- 

 wards, the branches put forth, and the leaves un- 

 fold. But the proboscis and maxillce do not 

 constitute the essence of the insect. On the 

 contrary, the head and its organs are in some degree 

 analagous to the root in plants, for they collect and 

 absorb the nutriment ; the truncus may be looked 

 upon as representing the stem, the limbs the 

 branches, the wings the leaves, the abdomen as a 

 kind of calyx, including the fructification. There- 

 fore, the great command, " increase and multiply," 

 will direct us to those parts which constitute the 

 essence of an insect ; but these, if it were possible, 

 it would be improper to use for characters {g) . Since 

 then the Instrumenta cibaria do not constitute the 

 essence of an insect, it is consequently a matter of 

 indifference whetlier the generic characters be 

 taken from them, or other parts that are mor^ 

 obvious (/f). In these small animals, I call that a 

 generic character which is constant through a genus 

 from whatever part it be taken. In some classes 



(g) Genitalluvi curiosior indagatio ahomittahilis dispUcct 



quamvis varia et singularis, (jiice tamen posset ad 



ordines naturales v'lam vionstrare. Lin. de IMammalibus. 



(A) In the Mammalia the teeth are easily examined, and 

 therefore, if constant, afford good characters. Nor do I pre- 

 tend to say that the Instrumenta cibaria of insects, assumed 

 under proper limitations, might not afford such as were equally 

 good, if they were equally easy of inspection. 



D 4 those 



