18 PACKARD, NOTES ON THE 



with green and bright red patches (Zygasna), or are wholly 

 green (Ino), or as in Procris, Ctenucha and allies, deep Prus- 

 sian blue, or with shades of dark brown with red about the 

 head or pro-thorax. An exception to this general rule is Eu- 

 dryas with its remarkable arrangement of colors. 



Of the two subfamilies into which this family is divided, the 

 Castniares approach nearest the Sphinges, while the lower sub- 

 family, the Zygaeninae, have the closest affinities with the iEge- 

 riadae. They both in the structure of the head resemble much 

 the iEgeriadae, since in them the clypeus is square, being 

 broader in front than in the Zygaenidae. But in the last named 

 group the epicranium is shorter, so that the antennas arise 

 nearer the base of the head ; also in the iEgeriadas, the occi- 

 put is nearly obsolete ; and they are remarkable from the fact 

 that the head is greatly advanced in front of the insertion of 

 the primaries. This is owing to the great length of the thorax, 

 which agrees with the slender abdomen, and long and narrow 

 wings. Owing to the last character the style of neuration 

 differs from the Zygaenidaa in the branches of the nervures pro- 

 ceeding straight out to the outer edge, and being parallel with the 

 costa and inner edge, which last is greatly elongated, and parallel 

 to the costa. Thus while the nervules in both families are very 

 short, one third as long as the whole wing, all arising very 

 near the outer edge ; in the typical Zygaenidas they are curved 

 more downwards, and are even shorter. In all the wing charac- 

 ters there is a much greater variation than in the Sesiadae, and 

 we have broad wings, becoming almost geometriform, being 

 equilaterally triangular, as in Euremia from India and China, 

 with long nervules, arising within the middle of the wings. 



Another character of importance is the form of the meso- 

 scutellum which differs from the Sphingidae and iEgeriadae in 

 being much longer, especially produced behind, where it is much 

 rounded. In Sphingidae it is subacute. In the typical Bom- 

 bycidae (Attaci) it is perfectly square behind. The tergum of 

 the meso-thorax affords better family characters than the other 

 parts of the thorax. 



Among the typical genera (Zygaena, &c.) the abdomen is 

 shorter than in the families mentioned above, though this is 

 a character of little value. 



