VI PREPACK, 



described as species, have not sufficient claim to that rank ; and 

 that others, perhaps yet but little known, and which are now 

 caWeiybrms or varieties, should be found truly distinct, I must 

 beg for that indulgence, without which, any one, undertaking the 

 investigation of such a genus, might weU shrink from publishing 

 the result of his researches. I cannot but hope, however, that 

 this work will assist those who take an interest in the genus, 

 especially any visiting the mountain districts of Clova, Braemar 

 and Teesdale, to identify our various British species with less 

 difficulty. , Should this be the case, I shall feel that the labour 

 has not been wholly in vain, and shall gladly receive from any 

 observer the result of further investigation, whether favourable 

 or adverse to my present opinions. 



JA8. BACKHOUSE, Jun. 



YouK, Ist Mo. 1856. 



