Vii ’ INTRODUCTION. 
form of the genitalia; but all these are secondary sexual characters, and no single 
character, or combination of characters, is found sufficiently constant throughout any 
assemblage of species to justify the establishment of a recognisable genus, with the 
exception of Apoclisis, proposed on account of the peculiarity of the cubital veins of 
the forewings, and Urbara Wkr., which possesses the same cubital neuration, but is 
in other respects even more distinct from the typical forms. Greater or less degrees 
of structural difference are accompanied with remarkable and confusing similarity of 
markings and general appearance. In the case of the genitalia, the divergences . 
might even convey an impression that they: have been evolved to prohibit inter-— 
breeding in instances where, without such precautions, confusion would be expected 
to occur. Some of these conclusions were not only surprising, but disappointing to a 
small committee decidedly predisposed to the retention and establishment of ‘separate 
genera, and we were constrained to admit that if any one of our number, at a 
distance from the others, had ventured upon such a bold course of amalgamation 
as has been finally adopted, he might well have been in danger of being regarded 
by the other two as an entomological crank, whose destructive work served only 
to stimulate their own preferably constructive tendencies. If any safety is to be 
found in numbers, we may claim at least the advantage of unanimity, until good 
evidence can be produced to upset our conclusions, and Mr. Meyrick’s latest papers 
give us good ground for claiming a general concurrence on his part. 
It was inevitable that in the course of this study much attention had to be given to 
questions of nomenclature, and, being responsible for the code known as the ‘ Merton 
Rules,’ Mr. Durrant and myself were anxious to ascertain on what grounds the 
members of a recent Zoological Congress had adopted what seemed to be a somewhat 
arbitrary system of selecting and maintaining Generic names by summary fixation of 
types without due regard for previous work done by critical authors. The rule that 
the Type of a genus cannot be regarded as fixed until it has been actually and definitely 
specified is now being largely adopted in America and perhaps elsewhere, but it is by | 
no means clear that those who accept this code were made fully acquainted with the 
reasonable objections to such a course. 
The main object of any Rules should surely be to secure priority and uniformity: 
priority not only for names, but for all published results of critical study; uniformity 
not by mere arbitrary decision, but by the application of unvarying principles which, 
consistently followed, could only lead to one definite result in each case—a_ result 
which, while securing priority in the fullest degree, should preserve for each worker 
the credit of his work until it could be proved to be incorrect. 
The rock on which the greatest split seems to have occurred has been the adoption 
