MORSE: ORTHOPTERA OF NEW ENGLAND. 
223 
wall which grow out as flat, hollow sacs containing blood and 
air-tubes (tracheae). Later, their walls unite, and linear thicken- 
ings along the walls of the trachea:e form longitudinal supporting 
ribs termed veins or nerves. The arrangement of these, termed 
venation or neuration, is of much importance in classification. 
.« ■«> i« In' In ^ 
Fig. 14. — Right tegmen of Carolina Locust, showing venation. (After Saussure.) 
Between the veins run numerous cross-veins, venules or veinlets, 
very thickly and irregularly placed on the base of the tegmina, 
fewer and more regularly arranged near the end of the tegmina 
and on the wings. 
The names of the various parts of the tegmen and wing, of the 
veins and the spaces between them, can most quickly be learned 
from the figures. (See Figs. 13, 14.) In the Band-winged Locusts 
••••:--::>A 
Fig. 15. — Right tegmen of Locust, with areas indicated. (After Saussure.) 
the wings are often brightly colored and bear a conspicuous dark 
transverse band. This divides the wing into a basal area {disk), 
the seat of the most brilliant color, and a clear, smoky, or spotted 
apex. The transverse dark band usually sends off, near the 
front margin of the wing, a small branch toward the base of the 
wing, which extends a distance varying with the species. 
"The principal veins of the tegmina of a locust diverge from 
the basal end and are seven in number. The one nearest the 
front or lower margin of the wing-cover is the 'sub-marginal' or 
'costal vein' (c). It is undivided, and may usually be traced for 
