GENERAL SUBJECT 



The CossiDAE, which belong to one of the more generalized fam- 

 ilies of the Frenatac, in that the secondaries possess three anal veins, 

 are derived phylogenetically, according to Hampson, (Cat. Lep. Phal. 

 I, p. 12), from the Zygaenidac, which in their turn are an offspring of 

 the Tincidac. Recent German writers (Spuler, Schmetterlinge Euro- 

 pas, Einleitung; Handlirsch, Die fossilen Insekten und die Phylogenie 

 der rezenten Formen,) make them direct descendants of the Tincidae, 

 and although our investigation of this group has not been sufficiently 

 extended for us to arrive at any definite conclusion, we incline to the 

 latter opinion. Our own studies of the N. American species have at 

 least failed to verify Hampson's statement that the spurs of the hind 

 tibiae are minute ; this is only true of the genus Zaizcra and to a cer- 

 tain extent perhaps of Givira and Acosshs; in other genera, notable 

 Hypopta and Cossnla, the tibial spurs are fully as well developed as 

 in many species of Noctuidae. 



The Cossid Venation is very characteristic and serves to define 

 the group sharply; on the primaries there are two, on the secondar- 

 ies three anal veins; with the exception of a cross-vein between the 

 two anal veins of primaries in the outer fourth of wing, which occurs 

 in one subfamily (Hypoptinac) (PI. I, figs. 1-4), all the anal veins are 

 separate from base of wing. On the primaries an accessory cell 

 (areole) is always present, formed by the anastomosing of the 

 branches of the radius; vein Mj is much nearer to the cubitus than to 

 radius, causing the former to appear four-branched; the median vein 

 is continued through the discal cell to the base of wing, often branch- 

 ing within the cell to form what is termed the "cellula intrusa." On 

 the secondaries the subcostal and radius are separate from base of 

 wing, occasionally with a cross-bar near or at the apex of the cell ; the 

 median vein is continued to the base of wing and the "cellula intrusa" 

 may or may not be present. The presence or absence of the "cellula 

 intrusa" we have found to be a very constant feature and consider it 

 of generic value; we have laid less stress on the fact that two veins 

 may be stalked or from a point as we have noticed considerable varia- 

 tion in this respect in individual specimens ; the anal cross-bar on pri- 

 maries in the outer fourth wing has proved one of the most reliable 



