300 ON THE EXISTENCE OF NATURAL GENERA. 



I have seen an Algerine insect, in Mr. Waterhouse's possession, 

 which closely connects the Orthoptera and Hemiptera, resem- 

 bling both the Blattidce and CimicidcE : and in the cabinet of 

 Mr. Stephens is another insect, which partakes of the charac- 

 ters of the Coleoptera and Strepsiptera. Granting therefore 

 all insects to be linked together in most easy gradation, which in 

 fact they are, would it be the language of nature to say, " This 

 butterfly is a distinct species of beetle ;" and vice versa ? It 

 may be answered, " No;" but it would be correct to say, " This 

 butterfly and this beetle are distinct species of insects." But 

 it unluckily happens, that if such stress be laid upon " links," 

 even " insects " can no longer be considered a distinct group ; 

 the transition from them to the Arachnoi'da, &c. being easy, and 

 equally so from one group to another, throughout animated 

 nature. And what is worse, the difficulty does not end here — 

 for animal and vegetable nature are as closely linked to each 

 other as animals are ; so that, by way of being correct, we 

 must speak of every palpable being, merely as a form of 

 matter, unless indeed we follow Bishop Berkeley in his theory, 

 that matter does not exist. 



But to return to the objection. It is said that in ento- 

 mology, " so gradual a connecting series may be formed from 

 one group to another, that it shall be impossible to draw the 

 line between them." This impossibility, however, I am dis- 

 posed to deny ; and in the definition I have indicated that, if 

 no where else, this line can be drawn where individuals, in 

 such a series, cease to have a single character in common with 

 those which precede them. 



Mr. Newman is of opinion, " that a genus should be established 

 for every species whose primary characters differ from those of 

 its congeners," and probably these would be true natural 

 genera ; for if the transitions from the great groups to each 

 other be so gradual, we may suppose those from the smaller 

 groups to each other to be still less abrupt, and the genera 

 indicated by these types may contain many species with which 

 we are at present unacquainted. 



But it was not my purpose here, to show how genera may 

 be distinguished, but if possible to prove their existence, 

 which I trust I have in some measure accomplished. If what 

 I have written should prove the means of exciting enquiry 

 and discussion, by which not only the existence of genera 



