INTRODUCTION. 
3 
if I were able to do so in a satisfactory manner. I hope, however, 
that the plan proposed with regard to Staudinger’s non-European 
species, and occasional references to allied North American forms, 
will help to increase the interest of the subject. 
Whenever possible these notices will be made from the 
examination of actual specimens ; but where this is not possible 
I shall, of course, be indebted to the works of other observers, and 
generally to the original figures or descriptions, to which due 
reference will be made. 
With regard to synonyms, only those will be given that are 
likely to be useful. The references to authors will be placed after 
the name of every species at the head of the description, and 
will include the principal works in which the insect is described. 
A short tabular notice of these will appear at the end of the 
volume, but in the meantime it will be found that the abbre- 
viations used will be such as are now commonly understood by 
entomologists. In giving the name of a species the reference to 
the author following the specific name will be understood to refer 
to that name only, and not necessarily to the generic name : 
example, Zegris Eupheme, Esper. The reference made to Esper 
concerns the specific name alone, the species thus named being 
the Papilio Eupheme of that author. The references to works 
treating of the genera will be given in their proper places. 
There are more than three hundred species of Ehopalocera, 
or Butterflies, occurring in Europe, all of which are distributed, 
somewhat unevenly, among ten families. 
It is usual to divide these ten families into three groups, 
characterized by the manner in which the caterpillar changes into 
the chrysalis. This arrangement seems to me both convenient 
and natural, and will be followed in the present volume ; it is 
shown in the following table : — 
