xii PREFACE. 



The author, in the following performance, may 

 be thought by many, to have multiplied species 

 without necessity; while others will probably object 

 to his having put those together, whose primdjacie 

 appearance is entirely different. To the first he 

 begs leave to observe, that insects are not so sub- 

 ject to vary as plants; moreover his discovery of 

 the sexes enabled him to detect those differences 

 that indicate gender, and therefore he could always 

 reduce the question, with respect to any particular 

 insect, into this small compass, viz. whether such 

 variations were likely to occur in the same sex ? 

 He does not, however, presume to affirm that he 

 has fallen into no mistakes in this respect ; for in 

 two of his subdivisions of genuine Apes{d), he fears 

 he has not been so successful, in uniting the sexes, 

 as in other families; and in general, where the 

 males and females differ very materially, as they 

 occasionally do both in colour and form, he has 

 probably, in several instances, been led to regard 

 them as distinct species. To the latter he must 

 reply, that he has never united two insects before 



(^d) The author alludes here to those Vespiform Apes, which 

 constitute a considerable part of the Fabrician genus Nomaday 

 and also to the Bomlinatrices of Linneus. Of these^ the for- 

 mer seems more subject to vary than any family of the genus ; 

 and almost all the distinctions of the latter being taken from the 

 colour of their hirsuties (which varies much, and often in the 

 same individual, in different periods of its existence) of course, 

 in describing them^ the entomologist must be liable to many 

 mistakes. 



considered 



