The Termites, or White Ants 
109 
the differentiation of individuals. To understand this claim it is necessary 
to attend more closely to the feeding habits. The food of termites con¬ 
sists almost exclusively, as has already been said, of wood. But this wood 
may be taken directly from the walls of the burrow or secured indirectly 
from another individual. In this latter case it consists of disjecta of undi¬ 
gested material, which, while mostly wood, must be mixed with other or¬ 
ganic material: because the termites keep their nests clean by eating their 
cast skins and the dead bodies of other individuals. This undigested mate¬ 
rial is called proctodeal food. In addition, a certain amount of evidently 
very different matter is regurgitated through the mouth from the anterior 
part of the alimentary canal. This is called stomodaeal food. As the young 
receive all their food from the workers, it is apparent that there is oppor¬ 
tunity for a choice, on the part of the nurses, in the kind of food given the 
young. And it is presumed by Grassi that such a choice is made, and that 
it results in the differentiation of the castes. As a matter of fact, such a 
differentiation of individuals is accomplished in the honey-bee community 
by feeding those larvae which the workers wish to make fertile queens “ royal 
jelly”—a rich food regurgitated through the mouth from the anterior part 
of the alimentary canal. This is done for the queens during the whole 
larval life, while larvae which are fed royal jelly for only one or two days, 
and then mixed pollen and honey for the rest of larval life, develop into 
workers. With the honey-bee, however, the workers are to be looked on 
as probably only arrested females. But in the case of Termopsis angusti- 
collis Heath has experimented by feeding members of 
various colonies, both with and without primary royal 
pairs, “on various kinds and amounts of food—procto¬ 
deal food dissected from workers, or in other cases from 
royal forms, stomodeal food from the same sources, 
sawdust to which different nutritious ingredients had 
been added—but in spite of all I cannot,” he says, 
“feel perfectly sure that I have influenced in any un¬ 
usual way the growth of a single individual.” 
This is by all odds the most important and interesting 
problem in termite economy, and the solver of it will do 
much for zoological science. 
A singular and primitive family of small insects, the 
Embiidae, of doubtful affinities, is represented by not 
more than twenty living species, of which but four 
occur in this country. The individuals do not live in 
communities as the termites do, but in structural characters they probably 
more nearly resemble these insects than any others. Fig. 139 illus¬ 
trates a typical Embiid. This species, Embia texana , is about one-quarter 
Fig. 139 .—Embia 
texana. (After 
Melander; en¬ 
larged.) 
