NORTH AMERICAN LEPIDOPTERA. 51 



The venation is distinctive. The primaries may have eleven or 

 twelve veins; vein one, the dorsal, subniedian, or iuterual 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 j)oint to the tip arises vein nine 

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

 near its termination in costa ; according 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 oft' 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 cos.a, 

 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. a|ncal) from the end of 

 the subcostal, or on a short stalk from that j)oint ; vein eight (costal 

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

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

 costal nervure). This venation is ty])ical 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 generally 

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



