80 INTRODUCTION. 



difficulties formerly alluded to, and partly to the 

 vast extent of the subject. Let any one attempt to 

 arrange and name a moderate sized collection of fo- 

 reign moths, and he will soon be convinced how little 

 has been done to facilitate his labours. The system 

 of Latreille, one of the few that professes to apply 

 to the whole subject, may now be regarded as little 

 more than an outline, which leaves a great mass of 

 the species altogether unprovided for. Hence the 

 necessity that continually arises, even when giving 

 the history of a comparatively limited number of 

 species, for the establishment of many new genera. 

 It must be admitted that such a step, in regard to 

 insulated species, and when there is no means of 

 distinctly pointing out the limits and relations of 

 the genus so constituted, is in some degree unsatis- 

 factory ; and it becomes even more so when the 

 genus is formed, as is sometimes necessarily the 

 case, from the mere inspection of an engraved figure, 

 destitute of those details of structure which should 

 enter into the generic definition. But when it is 

 found that the insect thus distinguished cannot with 

 propriety be included in any of the existing genera ; 

 that it affords prima facie grounds of distinction 

 which cannot be overlooked, there is no alternative 

 but to adopt this course. It is at least advancing 

 on the right path, although the progress may not 

 be so considerable as might be desired. 



There are few departments of entomology more 

 worthy of the attention of travellers in foreign coun- 

 tries than that now under consideration. Scarcely 



