22 INSECTS INJURIOUS TO FOEESTS. 
termitarium, after a careful examination to determine that no 
termites were already present. The earth in the cage was kept 
sufficiently moist in the endeavor, in so far as possible, to approxi- 
mate natural conditions. (Fig. 5, c.) 
The termitarium was ready for occupancy on April 8, and a chest- 
nut log infested with a colony of Leucotermes jiavipes was introduced. 
This log had the bark on and was partially buried. On April 9 a 
decaying oak stump containing a colony of the same species was 
also placed in the cage and partially buried in the earth. Several 
termite colonies in logs and stumps in the forest were kept under 
observation at the same time, and seasoned logs and slabs with 
loosened bark were placed near by under conditions similar to those 
in the cage. The following notes are based on observations of 
colonies of termites in the termitarium, colonies in small tin boxes, 
and colonies in nature. 
COMMUNAL ORGANIZATION. 
SITUATION OF THE NESTS. 
Termites in the eastern United States usually make their nests in 
decaying stumps or in logs and even small pieces of wood on the for- 
est floor, although they also inhabit dead standing trees as well as 
injured living trees. They never form mounds as in the Tropics. These 
soft-bodied insects always conceal themselves within wood or in 
earth as means of protection against sunlight and their enemies, in 
consequence of which much of the damage they do is hidden. Ter- 
mites of the genus Leucotermes are essentially wood destroyers and 
infest and seriously injure a great variety of crude and finished 
forest products which are in contact with the ground. The longi- 
tudinal excavations usually follow the grain of the wood, a and in the 
more sound wood their work is confined to the outer layers, where 
there is abundant moisture and incipient decay. A protective outer 
shell of wood is always left intact, since all except the winged, sexed, 
colonizing forms shun the light and are blind. Small, transverse, 
round tunnels which nearly pierce the outer shell are to be found 
when their tunnels closely approach the exterior. Sometimes the 
thickness of this protective shell is less than one-half millimeter. 
These may be soundings to see how nearly the surface is being ap- 
proached, or merely unfinished excavations for the exit of the sexed 
adults, or possibly they may be feeding burrows. Termites often 
take advantage of the burrows of other wood-boring insects, enlarg- 
ing and adapting them to their purposes; by these means they are 
a Termite work can be readily distinguished from that of carpenter ants, whose ex- 
cavations do not follow the grain. Sometimes in decayed wood, however, termites 
construct long, deep, but narrow, transverse galleries across the grain, forming ledges 
or shelves, 
