578 THE AMERICAN NATURALIST. [VoL. XXXIII. 
tion) of the two, as can be seen by comparing the lettering of 
Figs. 78, 79; the same number of anal veins and of accessory 
cubital veins exist in the two sexes. 
The lettering of the figures will serve to show the striking 
differences in the development of the remaining veins in differ- 
ent members of the order. Thus, for example, while the radius 
is the most prominent vein in the fore wing of the cockroach 
(Fig. 74), in Œcanthus (Figs. 78, 79) it is the least developed 
Fic. 79. — Fore wing of a male nymph of €Ecanthus. 
of the principal veins; or, to take another example, the sub- 
costa is greatly reduced in the cockroach (Fig. 74), while in 
the Acridid (Fig. 75) and in the Locustid (Fig. 76) it is as well 
developed as any other vein. 
In none of the Orthoptera that we have examined is the cos- 
tal trachea distinctly preserved. Frequently, as in the Acridid 
(Fig. 75) and in the Locustid (Fig. 76), there is a prominent 
branch of the subcostal trachea which simulates a costal 
trachea; but that this is merely an overgrown branch of the 
subcostal trachea is evident when a series of forms are studied ; 
in the hind wing of Conocephalus (Fig. 76) there are two such 
branches. 
It will be remembered that in our hypothetical type the sub- 
costa is two-branched, and that the branches are designated 
as Scr and Scz respectively. A good example of this typical 
branching of the subcosta is afforded by Nemoura.! But there 
1 American Naturalist, vol. xxxii, p. 238, Fig. 8. 
