16 THE POISON OF ANTS. 
is not thus fired at the enemy from a distance, there 
are two cases in which the aculeus might be allowed to 
fall into disuse. Firstly, those species which fight 
with their mandibles might find it on the whole most 
convenient to eject the poison (as they do) into the 
wounds thus created. Secondly, if the poison itself is 
so intensified in virulence as to act through the skin, 
a piercing instrument would be of comparatively small 
advantage. I was amused one day by watching some 
specimens of the little Cremastogaster sordidula and 
the much larger Formica cinerea. The former were 
feeding on some drops of honey, which the Formicas 
were anxious to share, but the moment one approached, 
the little Cremastogasters simply threatened them 
with the tip of their abdomen, and the Formicas 
immediately beat a hasty retreat. In this case the 
comparatively large Formica could certainly have had 
nothing to fear from physical violence on the part of 
the little Cremastogaster. Mere contact with the 
poison, however, appeared to cause them considerable 
pain, and generally the threat alone was sufficient to 
cause a retreat. 
However this may be, in their modes of fighting, 
different species of ants have their several peculiarities. 
Some also are much less military than others. Myr- 
mecna Latreillii, for instance, never attack, and 
scarcely even defend themselves. Their skin is very 
hard, and they roll themselves into a ball, not defend- 
ing themselves even if their nest is invaded ; to pre- 
