PAET II. 



SYSTEMATIC. 



Descriptions of Genera and Species. 



PRELIMINARY OBSERVATIONS. 



IN this work it has been necessary to consider a 

 question on which great differences of opinion exist, 

 and may fairly do so, viz. whether if an author 

 described and figured an immature form of one of the 

 Acarina, believing it to be adult and named it; and 

 another author subsequently described the adult under 

 a different name the earlier name of the larval form or 

 the later name of the imago should be retained as that 

 of the genus or species as the case might be. I have 

 considered it best to retain the name based upon the 

 adult, and have done so in the few instances where such 

 circumstances occur : my reasons are as follows. 



There is not any authoritative English rule upon the 

 subject; neither the " Rules for Zoological Nomencla- 

 ture " drawn up by H. E. Strickland at the instance of 

 the British Association in 1842, after consultation with 

 many British and Foreign Zoologists, which has always 

 been the principal authority for British zoological nomen- 

 clature, nor the report of the Committee appointed by 

 the same Association in 1864 to consider whether any 

 alteration was required in those rules, say a word upon 

 the question ; nor do the Rules for the nomenclature 



