ISOPTERA OF NEW GUINEA. 
373 
After careful examination, I could see that after this jump, the man¬ 
dibles remained in the same position, i. e> like an X.» (L. Biró.) 
This observation is of great interest, as showing that the soldiers 
of this remarkable group, represented in Australia, in the Indo-Malayan 
region, in Africa and in South America, are evidently true soldiers, like 
those of all other Termites, whose function is defence only. 
The fact that these soldiers can spring is. well known, and the 
structure of their extraordinary long mandibles led M. Silvestri to think 
that these forms had not the habitual function of the soldier-caste, being 
quite incapable of defence. And he sought to justify their presence by 
attributing to them a most extraordinary function. 
Speaking about South American species, M. Silvestri* said: 
«... in altre specie, le mandibole non sono atte all’ offesa, ma ad 
emettere un forte suono e a far saltare in dietro il soldato. In quest’ ultimo 
caso, il soldato è diventato una sentinella avanzata (!!) che appena scorto 
un pericolo, ne dà avviso alla colonia e nello stesso tempo si pone in salvo 
esso stesso saltando in dietro, operazione che viena fatta serrando rapida¬ 
mente le lunghe mandibole poggiate al suolo.»** 
The unlikeliness of such an hypothesis is so evident, that it seems 
to me quite superfluous to discuss it : the single fact that these Termites 
live in closed nests, and that their soldiers are never found out 
of their habitations, is sufficient to definitively upset Mr. SilvestrTs 
inconceivable theory. 
Furthermore, Mr. Biro’s observations prove that, notwithstanding 
their considerable length, the mandibles of these soldiers are certainly 
defensive. 
The act of springing, when closing the mandibles, is, without doubt, 
accidental, and may be explained as follows : 
It seems to me evident that it is due to the considerable size of 
the mandibles and the large development of the muscular system which 
moves them, in comparison with the lightness of the body. It is clear 
that, when in anormal situation, viz. in a gallery of the nest, it is impos¬ 
sible for a soldier to be appreciably displaced by moving his mandibles 
even with the largest effort allowed by the limited diameter of the tubu- 
* Redia, I, p. 151 (1903). 
** «. . . in other species, the mandibles of the soldier are incapable of attack, 
but emit a distinct sound and cause the soldier to jump backwards. In this case, 
the soldier has become an «advanced sentinel» who, immediately he scents danger, 
warns the colony and at the same time puts himself in safety by jumping back¬ 
wards, a movement which is caused by the closing rapidly together of the long- 
mandibles resting on the ground.» 
