LEPIDQPTERA. 283 



discal cell (Fig. 334). The only exception to these char- 

 acters known to us is shown by certain genera (e.g., Heteroph- 

 leps and Dyspteris) in which, owing to a large expansion of 

 the costal area of the hind wings, veins II and III have 

 been pulled apart as it were, and are connected only by 

 a cross-vein near the middle of the discal cell (Fig. 335). 

 In a single genus (Paleacrita) not belonging to this* family 

 veins II and III of the hind wings coalesce to the middle of 

 the discal cell ; but this genus lacks the accessory cell in the 

 fore wings characteristic of this family. 



This family ranks second in size among the Geometrid 

 families, and contains many common species. 



The White-striped Black, Eucha?ca albovittata (Eu-chce'ca 

 al-bo-vit-ta'ta). This beautiful little moth, which occurs 

 from the Atlantic to the Pacific, is the most easily recog- 

 nized member of the family. It expands about seven eighths 

 of an inch, and is of a uniform black color, with a single, very 

 broad white band extending across the fore wing from the 

 middle of the costa to the inner angle, where it is usually 

 forked. The fringe of the wings is white at the apical and 

 inner angles of both pairs ; sometimes the white is lacking 

 on the inner angle of the hind wings. The early stages of 

 this beautiful moth are unknown. 



The Spear-marked Black, Plemyria hastata (Ple-myr'i-a 

 has-ta'ta). This is another black-and-white species, occur- 

 ring from the Atlantic to the Pacific. It is much larger than 

 the preceding, expanding one and four tenths inches. It is 

 black, striped and spotted with white. It varies greatly as 

 to the number and extent of the white markings. The 

 most constant mark is a broad white band crossing the 

 middle of the fore wings, and often continued across the 

 hind wings. Near the middle of its course on the fore 

 wing this band makes a sharp angle pointing outward ; and 

 just beyond the apex of this angle there is usually a white 

 spot. This spot and angular band together form a mark 

 shaped something like the head of a spear. In some speci- 



