45 
(Fig. 25, a). The posterior or narrow end, which issues first 
= ee (7s SS from the oviduct, is 
e: fs =. thickened, and gener- 
ally shows two pale 
rings around the dark- 
er tip (Fig. 25, 6). This 
is pushed close against 
Pe . t bad the bottom of the bur- 
ace ae dalsf/ E row, which, being cy- 
Fig. 25.—Egg-mass of Rocky-Mountain Locust—a, lindrical, does not per- 
from the side, within burrow; b, from beneath; ¢, q is 
from above; enlarged. (After Riley.) mit the outer or two 
side rows to be pushed quite as far down as the two inner rows, 
and for the very same reason the upper or head ends of the 
outer rows are necessarily bent to the same extent over the 
inner rows, the eggs when laid being somewhat soft and plas- 
tic. There is consequently an irregular channel along the top 
of the mass (Fig. 25, c.) which is filled only with the same frothy 
matter that surrounds each egg, which matter occupies all the 
other space in the burrow not occupied by the eggs. ‘The 
whole plan is seen at once by a reference to the accompanying 
figure, which represents, enlarged, a side view of the mass 
within the burrow (a), and a bottom (0) and top (c) view of the 
same, with the earth which adheres to it removed.”’ 
‘‘Hiach female of the Rocky-mountain locust lays on an 
average about three egg masses; this is done at intervals of 
two weeks, so that the egg-laying season extends from six to 
eight weeks.” 
“The egg is surrounded by a shell consisting of two layers, 
of which the outer one is thin, semi-opaque, thus producing the 
creamy-yellow color; highly magnified it appears (Fig 26, a) 
densely and minutely pitted or rather netted with minute and 
hexagonal ridges (Fig. 26, b.) The inner and thicker layer is 
deep yellow, smooth and translucent, so that the form of the 
embryon can be plainly seen when maturing inside. The outer 
layer is quite brittle, but the inner one very tough, requiring 
a strong pressure to rupture it. As the embryon within 
matures (Fig. 26, c), the egg-shell becomes weakened, and 
the egg plump and somewhat more transparent. By the 
muscular efforts of the enclosed insect, but chiefly by the 
thorns arming the hind tibia, Fig. 26, e, the shell is eventually 

