290 B. GRASSI AND A. SANDIAS. 
itself of them when they are over-abundant. These 
facts imply the possession by Termites of a faculty 
which may be termed a sense of proportion or nume- 
rical sense. 
By way of conclusion, I must add that though I have had 
Calotermites under observation for several years, I may still 
have failed to detect a great part of their marvellous instincts. 
This is owing to two circumstances: 1, they are often slug- 
gish ; 2, when a nest is opened the population is thrown into 
such a state of astonishment that it usually does nothing but 
run away and give signals of alarm. And almost all the 
observations here recorded are due to the method of employ- 
ing tube-nests. 
Tue CoLony oF TERMES LUCIFUGUS. 
1. Situation and Nest. 
Several writers, particularly Lespés, have published observa- 
tions on this subject ; but I shall summarise merely my own 
investigations. 
Here in Sicily Termes lucifugus usually inhabits plants, 
rarely furniture or the wooden beams of buildings. It is most 
common in plants of which the stem or tap-root measures at 
least three quarters of a centimetre in diameter; but when it 
has once entered a stem or large branch it will pass on into 
the very smallest twigs and roots. It mines irregular galleries, 
and often avails itself of old beetle-burrows (Bostrychus, 
&c.); Calotermes does the same thing. Like that species, 
Termes leaves the outer layers untouched, so that a trunk 
may be completely mined out and yet appear sound, while the 
hand can easily be thrust into it by breaking through the thin 
intact superficial layer. 
Owing to the extreme tenuity of this layer in the smallest 
roots invaded, the galleries may appear at first sight to be 
tunnelled directly in the ground ; but I have never been able 
definitely to establish the existence of such a mode of con- 
struction. 
