180 POMONA COLLEGE JOURNAL OF ENTOMOLOGY 



the wing membrane transparent and will bring the veins into sufficient con- 

 trast to make them easily seen. The veins of the figure are numbered to 

 correspond with the system in common use by describers of this family, and 

 they are also given the names used where numbers are not available. 



The secondaries, or hind wings (Fig. 71) have two free or internal 

 veins, vein 8 is out of the sub-costal a little beyond base, and the median 

 vein is either 3 or 4 branched, depending upon whether 5 is from a short 

 spur close to 4, or whether it is obsolescent and out of the obscure cross- 

 vein closing the cell. At the base of the costal margin there is, in the male, 

 a single spine or spur, the frenulum, which fits into a loop or retinaculum 

 attached to the costa of primaries, and holds the wings together ; in the 

 female there are three or four weaker bristles, and these are held by crossed 

 scales on the under-side of the median cell. This gives us a convenient way 

 of determining sex in this family, the loop of the males or crossed scales 

 of the females being very readily determinable, as a rule. There are, however, 

 a few exceptions to this rule; the half a dozen species of Bntcliiiii and 

 Stictopterini having the frenulum single in the female as well as the male, 

 but no loop in the female. 



On the basis of the difference in vein 5 of the secondaries, the Noctuidse 

 are divided into two series — XhcTrifidac in which the vein is nearly or quite 

 lost and, when traceable, is from the cross-vein, well beyond the end of the 

 median — and the Onadvifidac in which vein 5 is nearly or quite as strong as the 

 others and is connected at base by a strong spur with the end of the median. 

 In another way of putting it, the median vein is 3-branched in the one case, 

 4-branched in the other. The diiiference can be readily seen by comparing 

 any large species of Hadcna or Mamcstra with a Catocala. 



The body of the Noctuids is usually stout and well-developed, very few 

 species having large or frail wings, and the body vestiture may be hairy or 

 scaly, the differences furnishing bases for generic distinctions. 



The abdomen is quite frequently tufted on the dorsum, and sometimes 

 along the lateral edges of the segments. It is rarely much longer than the 

 anal angle of the secondaries, and in the Quadrifidac tends to become cylindri- 

 conic and smoother. 



The thorax usually has a well-developed collar, which may be produced 

 at the sides or middle, or even projected forward into a distinct hood. The 

 patagia are usually well-marked and quite usually sufficiently up-lifted to give 

 the thorax a distinctly squared appearance. On the dorsum the vestiture may 

 be flat and smooth, formed into a keel-like ridge, produced into anterior or 

 posterior tufts or both, or there may be a divided crest through the center; 

 all these furnishing bases for generic divisions. 



The head is usually well developed, rarely retracted, and the eyes are 

 usually round and more or less globose. In this matter there are differences, 

 however, and in some series reniform or kidney-shaped eyes occur. The 

 front of the head is usually smooth, slightly convex ; but it sometimes becomes 

 protuberant, l)ulging, roughened or furnished with ]iroccsse.s of various kinds ; 

 all these modifications being used in systematic work. The antenna- are al- 



