86 INTRODUCTION. 



Each of these three sections is then divided into 

 tribes^ according to characters derived from the ca- 

 terpillars and the perfect insect. Among those 

 furnished hy the latter, the most important are con- 

 sidered to he the numher of ambulatory legs and 

 the form of the palpi. The genera are characterised 

 by the form of the caterpillar and chrysalis, by the 

 dispositions of the nervures of the wings, the form 

 of the antennae, legs, palpi, thorax, &c. of the per- 

 fect insect. 



