LEPIDOPTERA. 
215 
wing near its base a small lobe (Fig. 243, j), which extends 
under the costal margin of the hind wing; while the greater 
part of the inner margin of the fore wing overlaps the hind 
wing. This arrangement assures the acting together of the 
two wings. 
This projecting lobe is named the jugum or yoke; and the 
moths possessing this organ are termed the Jugatae or the 
Jugate Lepidoptera. 
This suborder includes only two families; one represented 
by minute moths, the other by moths of medium or large 
size. 
Family Hepialid^e (He-pi-al'i-dae). 
The Swifts . 
The members of this family are of medium or large size. 
Figure 244 represents one of the larger species. Our best 
Fig. 244 .—Hepialus argenteomaculatus . 
known forms are brown or ashy gray in color, with the wings 
marked with silvery white spots. 
It is said that these moths fly near the earth, and only in 
the evening after sunset, hiding under some low plant, or 
clinging to the stalk of an herb during the day. Some of 
them fly with extreme rapidity, with an irregular mazy flight, 
and have, therefore, been named Swifts by collectors. They 
are attracted to lights. Figure 238 represents the venation 
of the wings of Hepialus (He-pi'a-lus). 
