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NINTH ANNUAL KEPOKT 



IFig. 21.1 



each egg, but so as to best facilitate the escape of the young 

 locust; for as the bottom eggs were the first laid and are gen- 

 erally the first to hatch, their issue would, in their efforts to escape, 



disturb and injure the other 

 eggs, were there no provision 

 against such a possibility. The 

 eggs are, indeed, most care- 

 fully placed side by side in 

 four rows, each row generally 

 containing seven. They 

 ^^ oblique a little, crosswise of 



Egg-mass of Rocky Mountain Locust:— a, from the Cylinder. (Fig. 21, a). The 

 the side, within burrow; b, from beueath; c, from 



above— enlarged. postorior Or uairow end which 



issues first from the oviduct is thickened, and generally shows two pale 

 rings around the darker tip (Fig. 22, a). This is pushed close against 

 the bottom of the burrow which, being cylindrical, does not permit 

 the outer or two side rows to be pushed quite so 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 plastic. There is, 

 consequently, an irregular channel along the top of the mass. (Fig. 

 21, c) which is filled only with the same frothy matter which surrounds 

 each egg and occupies all the other space in the burrow not occupied 

 by the eggs. The whole plan is seen at once by a reference to Figure 

 21, which represents enlarged, a side view of the mass within the 

 burrow (a), and a bottom (b) and top (c) view of the same, with the 

 earth which adheres to it, removed. 



HOW THE YOUNG LOCUST ESCAPES FROM THE EGG. 



Carefully examined, the egg-shell is found to consist of two layers. 

 The outer layer which is thin, semi-opaque, and gives the pale cream- 

 yellow color, is seen by aid of a high magnifying power to be densely, 

 minutely and shallowly pitted ; or, to use still more exact language, the 

 whole surface is netted with minute and more or less irregular, hexag- 

 onal ridges (Fig. 22, a, h). The inner layer is thicker, of a deeper yel- 

 low, and perfectly smooth. It is also translucent, so that, as the hatch- 

 ing period approaches, the form and members of the embryon may be 

 distinctly discerned through it. The outer covering is easily rup- 

 tured, and is rendered all the more fragile by freezing; but the inner 

 covering is so tough that a very strong pressure between one's 

 thumb and finger is required to burst it. How, then, will the embryon, 

 which fills it so compactly that there is scarcely room for motion, 



