INTERRELATIONS OF INSECTS 319 
substitution royalties may contain workers or even soldiers 
capable of laying eggs. 
Architecture.—\Vhile many termites simply burrow in dead 
wood, other species construct more elaborate nests. A Jamai- 
can species builds huge nests in the forks of trees, with covered 
passageways leading to the ground. 
In parts of Africa and Australia, where they are free from 
disturbance, termites erect huge mounds, frequently six to ten 
and sometimes eighteen or twenty feet high, with galleries 
extending as far below the 
MiGs 275% 
surface of the ground as 
they do above it. These 1m- 
miense stiuctutes (Fig. 275) 
consist chiefly of earth, ce- 
mented by means of some 
secretion into a stony clay, 
with which also much excre- 
mentitious matter is mixed; 
they are pyramidal, colum- 
nar, pinnacled or of various 
other forms, according to 
the species, and are perfor- 
ated by thousands of pass- 
ages and chambers, while 
there are underground gal- 
leries extending away from 
the mound to a_ distance 
of often several hundred Termite mound, Kimberley type, Australia. 
ner —After SAVILLE-KENT. 
An extraordinary type of mound is constructed by the 
“compass,” or “meridian,” termites of North Australia, for 
their wedge-shaped mounds (Fig. 276), commonly eight or 
ten feet high, though sometimes as high as twenty feet, are 
directed north and south with surprising accuracy. By means 
of this orientation the exposure to the heat of the sun is re- 
duced to the minimum, as occurs also in the case of many Aus- 
