INTRODUCTION Ml 



Finally with regard to the Microlepidoptera Mr. 

 August Busck of the U. S. National Museum has had the 

 kindness to read over our whole manuscript relating to this 

 group, suggesting many important changes in connection 

 with the sequence of the families and genera, a fact which 

 has rendered this portion of the list much more up-to-date 

 than we could ever have hoped for without Mr. Busck's 

 generous assistance. 



With regard to certain generic terms we might note 

 that, following the majority of the European authorities, 

 we have disregarded Hubner's Tentamen' as being un- 

 published; this has resulted in several rather unfortunate 

 substitutions, notably the displacement of the well-known 

 genera Olethreiites and Coleophora in favor of 'Verzeich- 

 niss' names which are not so generally known; we feel, 

 however, that such changes, while regrettable, should be 

 made for the sake of uniformity in the list and in accord- 

 ance with a strict adherence to the rules of nomenclature. 



In the text we have as far as possible used the sub- 

 divisions a, l>. c, etc., to denote geographical races which 

 have often been listed, especially in Europe, as rat: The 

 term form we have applied to a variety which exists along- 

 side the nimotypical form or which may be a seasonal one 

 and we have confined the term ab. to so-called freak speci- 

 mens or sports. In many instances, of course, our grouping 

 is more or less tentative. 



Certain European and foreign species which have been 

 erroneously recorded from North America as well as a few 

 species in which the type material, although stated to be 

 North American, has proved foreign we have omitted and 

 append a list of these at the conclusion of the work. 



