132 BULLETIN 38, UNITED STATES NATIONAL MUSEUM. 



species are also most closely allied. The large degree of uniformity in 

 geuital structure robs us of oue of our safest and most certain guides, 

 while the extreme range of variation in many of the forms makes the 

 limitation of species difficult. It is in this series, too, that constant 

 additions are being made to the species. Scarcely a collection reaches 

 my hands that does not contain some markedly distinct species, and 

 our work of a monographic nature must remain partly tentative until the 

 western region has been so thoroughly explored that the additions are 

 not so constant. 



In adopting the generic term Carneades I have consulted convenience 

 and merit more than jiriority. Mr. Grote in this case recognized the 

 frontal structure as diifering from Agrotis, but he was evidently igno- 

 rant of how many species agreed with his generic type in this respect. 

 His earlier genus. Eucoptocnemis for Jimhriar is, I have not used because 

 I am not sure the insect really belongs here. I have seen it but never 

 had a chance to study it. I know positively that many of the exotic 

 and European species must find a place in this same series, but have 

 not been able to apply the generic terms which exist in abundance to 

 any type with which I was acquainted. JSo large an assemblage, 

 agreeing so closely in structural characters, proved difficult of sub- 

 division, since I was reduced to characters of maculation and colora- 

 tion. Some little intelligence and care will therefore have to be applied 

 in referring some of the species to their respective series. 



First in the line I place a small group of which tvilsonii is typical. 

 It differs from all the others in the longer wings and depressed costal 

 margin. The appearance is somewhat like the auxilliaris series from 

 which the structural characters well separate it. 



Following this is the group quadrideiitata, which is characterized by 

 the name of its type. Veins 3 and 4 and G and 7 are marked with 

 white, and strongly indent the s. t. line, the spurs usually attaining the 

 outer margin. The feature is a distinctive one and there is only one 

 species in which there is room for doubt as to its reference here. The 

 species are not very well separated and there may be more or less than 

 1 have indicated. 



Group pitychrous differs by the general indefiniteness of maculation. 

 Sometimes the color is uniform, sometimes the lines are wanting, and 

 sometimes the lines are indicated or even fairly distinct, and the ordi- 

 nary spots are vague and indefinite. The median shade line is never 

 ])resent, and the cell is never black tilled. Most of the species are 

 readily referred here, and only a few, which will be more particularly 

 referred to hereafter, are liable to cause doubt. 



Messoria is typical of another group, all the members of which have 

 the median shade line evident. The cell is never distinctly black filled, 

 and the lines are sometimes the onlj' definite feature of maculation. 

 Some of the species here, which vary in the line of an obsolescence of 

 maculation, may create doubt with a small number of specimens, but 



