138 Psyche [August 
and broadened into feet, which also overlap one another and are 
cemented to whatever foundation the ootheca is being constructed 
upon. The feet of the egg plates (which also slightly overlap each 
other) rest upon and are cemented to the feet of the coverstrips — 
thus an air-space is left between the mass of egg chambers and the 
outer casing formed by the coverstrips. This air-space is, how- 
ever, often roughly divided into cells by the ragged edges of the 
egg plates projecting between the flanges of the chambers, as indi- 
cated by dotted lines at 22, Fig. 5, Pl. 1. The coverstrips at the 
two ends of the ootheca are brought together and overlapped very 
much like the planking at the bows and stern of a boat. There 
are usually two or three roughly-formed smaller chambers, with- 
out eggs, at both ends of the egg-case. Those at the back end (in- 
creasing in size) form the foundation or support for the egg cham- 
bers proper; those at the front end (decreasing in size) bring the 
chambers gradually small enough to be closed by a single central 
plates (Cpy Fig:k2:)Pl. 1); 
In brief, the ootheca consists of an outer casing formed of over- 
lapping coverstrips, within which are two parallel rows of egg 
chambers, so cemented together as to form a hard, tough mass. 
The process of construction is somewhat as follows: A small 
plate (B, Fig. 2, Pl. 1) forming the back end of the ootheca having 
been cemented to the bark or other object, an outer coverstrip 
(CVS, Fig. 2, Pl. 1) is attached each side. Two or three more 
small but increasing plates are added, with their respective cover- 
strips, so that the feet of the latter now project forward some dis- 
tance along the bark, and form a foundation for the feet of the egg 
plates. An egg plate (EP, Fig. 2, Pl. 1) is now formed against 
the last small plate (E, Fig. 2, Pl. 1), a flap (FL, Figs. 1 and 3, 
Pl. 1) is added, an outer coverstrip (CVS, Fig. 2, Pl. 1) attached, 
a closing membrane (CM, Fig. 1, Pl..1) stuck on, and finally the 
eggs laid in the numbered order. After the eggs are laid and before 
the next egg plate covers them they are, nevertheless, covered 
with a thin film of colleterial matter, extending to the top of 
the closing membrane. The superabundant colleterial matter 
also becomes (by mutual pressure of eggs and egg plates) 
squeezed into the interstices between the eggs, forming lit- 
tle ridges or partitions between the eggs, rather deep near the outer 
