OF WASHINGTON, VOLUME XVI, 1914 53 



A parallel case is that of the Cygnodiida?. Until a few years 

 ago the species of this group were classed in the same family 

 as the Cosmopterygidae, which they resemble superficially very 

 much. In a paper before this Society in 1909, I pointed out, as 

 Herrich-Schaffer had already figured without realizing its im- 

 portance, that some of the genera of this group have nine veins 

 in the hind-wing and therefore cannot be derived from a stock 

 where the vein reduction has already taken place. 



Incidentally these two examples illustrate the value of conscien- 

 tious figures, which depict all the student sees, not merely what he- 

 wants to see. In the venation plates of these two old authors, 

 Herrich-Schaffer and Stainton, we have had before us for more 

 than half a century, the faithfully presented evidence of important 

 phylogetaetic significance, which only now has been realized and 

 in both cases it was this evidence that gave the initiative to further >- 

 study and better understanding. 



A very satisfactory appreciation of the genera has been reached 

 by the study of the wing venation. There is no doubt that most 

 of the genera recognized at present are natural entities. The 

 component species of any genus agree in practically all characters 

 except in color and in secondary sexual male characters and even 

 these latter, as well as the color scheme and pattern are often 

 peculiar to a genus, differing among its species only in details. 



Their biology and larval characters also prove that the present 

 day genera are natural entities. In very many cases it is possible 

 to definitely determine the genus of a Microlepidopteron merely 

 from the work, or the mode of pupation or some other biological 

 peculiarity. The mines of Phyllonorycter (Lithocolletis) , Tischeria, . 

 Phyllocnistis, and Nepticula, or the cocoons of Bucculatrix, Mar- 

 mara, or Gracilaria are familiar examples of this fact. 



Likewise, we now have a reasonably satisfactory understanding 

 of the grouping of the genera. There is no doubt that practically 

 all families at present recognized are actual natural groups of 

 closely correlated genera, agreeing in essential pterogostic and 

 oral characters, as well as in general habitus, often exhibiting 

 even a common pattern scheme and a similar biology. 



It is when it comes to a phylogenetic valuation of these so- 

 called families, that there is considerable room for improvement. 

 In other words, the groups of genera, which, by nearly unanimous 

 consent are called families, are phylogenetically of very different 

 systematic value. For example, the characters which separate 

 Cosmopterygidse and the Gelechiidae from the Xyloryctidse or 

 from the CEcophoridse and Blastobasidae are not nearly as funda- 

 mental as those which distinguish the Coleophoridse or the Acro- 

 lophidse, even though they may be fully as easy to observe, and the 



