NORTH AMERICAN LEPIDOPTERA. 51 



The venation is distinctive. The primaries may have eleven or 

 twelve veins; vein one, the dorsal, submedian, or internal vein (sub- 

 median nervure) runs from root to the internal angle, and is furcate 

 at base. The discal cell is usually very short and narrow, rarely 

 more than one-third the length of costa. From the median vein, 

 forming the lower margin of cell, two (medio posterior nervule), is 

 given off usually basad the middle; vein three (medio central ner- 

 vule) starts from the same vein nearer its end; vein four (medio 

 superior nervule) runs from the end of the median to usually about 

 the middle of the outer margin. The cross vein closing the cell 

 (^discal nervure) is usually oblique, and from it near its middle, 

 though usually nearer to four than six, vein five (disco central ner- 

 vule) runs to the outer margin. The subcostal is usually close to the 

 costa and gives off at its outer third, vein eleven (first subcosto mar- 

 ginal nervule) ; half way from this point to the tip arises vein nine 

 (third subcosto marginal nervule), which may or may not branch 

 near its termination in costa ; a(^cordiug as it branches or not, the 

 wing has either eleven or twelve veins ; it is an inconstant factor, 

 varying in the same species ; usually it is not branched. From the 

 end of the subcostal arise six and eight ; the latter (subcosto apical 

 nervule) to the apex, giving off seven basad the middle (subcosto post- 

 apical nervule) to the outer margin ; six (subcosto inferior nervule 

 runs to the margin. Vein twelve, the costal vein runs to the cosra, 

 free from base at a variable distance therefrom. 



The secondaries have two internal veins, 1 a and 1 b (internal and 

 submedian). The cell is usually short and small here also; it gives 

 rise to two, three and four (medio posterior, m. central and m. supe- 

 rior nervules), the latter from the end. The cross vein is oblique, 

 giving rise to five (disco central nervule) at about its middle ; veins 

 six and seven (subcosto postapical and s. c. apical) from the end of 

 the subcostal, or on a short stalk from that point; vein eight (costal 

 vein)-^-ee from costa to the costal margin above the apex ; it is con- 

 nected near base Avith the subcostal vein by a short branch (inter- 

 costal nervure). This venation is typical of the family and thor- 

 oughly constant in all its modifications. 



Throughout this paper I have followed the European (Continental) 

 practice of indicating the veins by numbers rather than names. 

 This has been recently objected to by Dr. Packard, as unscientific, 

 but I prefer to be unscientific until some nomenclature is generallv 

 agreed upon. At all events it seems nuich more simple to refer to 



