THE SUBJECT NOT EXHAUSTED 419 



group. With attention directed to the number of species 

 actually existing, it is probable that the half-score described 

 by Bate and Westvvood as belonging to the British fauna 

 will soon prove to be but the nucleus of a far larger com- 

 ]3any. By accepting the view that no parasite has more 

 than one species of host, we may greatly simplify the 

 otherwise bewildering task of naming specimens, and so 

 far leave the mind at leisure to grapple with the other 

 numerous and intricate difficulties connected with this 

 little-known tribe. 



