through the mound, rising and falling in vertical depth,
intercommunicating frequently, but with occasional cul-de-sacs, and in
places expanding into chambers, of which there may be three or four
large ones. The stored materials are found in some, but not necessarily
all, of these chambers, and may also occupy considerable lengths of
ordinary tunnel, especially when the quantity present is large. Small
evaginations of the tunnels frequently contain lesser caches, and it is
in such pockets that bits of fresh material are placed during a growing
season, or that grain supplied the previous night for bait is usually
found.

The main masses of storage are most often found centrally located at
depths of from 15 to 57 centimeters, although at times one may find a
cache near the periphery of the system and as near the surface as 2 or 3
centimeters. In the latter case the materials are subject to wetting
from rains, and consequent spoilage.

The major portion of the whole tunnel system is within about 50
centimeters of the surface of the mound, but usually some one branch
tunnel goes to somewhat greater depth, and this is likely to be the one
containing the nest; this is also likely to extend toward or beyond the
periphery of the main system, and always ends blindly. Such a one, from
which two young were taken on January 31, 1920, was at a depth of about
65 centimeters, and about 1-1/2 meters beyond the periphery of the mound
itself.

The individual tunnels average about 8 centimeters in height, and about
11 centimeters in width, though the variation, especially in width, is
considerable. The expansions mentioned as being the chief places of
storage are from 15 to 25 centimeters in diameter, and may or may not