128 Notes on the Leaf-cutting Ants of Trinidad. [February, 
pair of spines. The thorax is very sharply constricted 'in the 
middle, the fore part, or prothorax, carrying the first pair of legs 
and a pair of spines upon the dorsal surface. The hinder part, or 
meso-metathorax, carries the other pairs of legs and two pairs of- 
spines. The cutting instruments are a pair of long extremely 
sharp-pointed mandibles finely serrated upon their inner surface, 
which may be used as saws or nippers. The workers vary ex- 
tremely in size; individuals are met with only three-sixteenths of 
an inch in length, while others attain a length of nine-sixteenths. 
These smaller (younger) ants accofpany their older sisters in 
their expeditions but rarely carry leaves. They may often be 
seen riding upon the burdens of their older and larger sisters as 
if tired. I have observed as many as three clinging to a leaf 
which was carried with apparent ease by one of the larger ants. 
A number of these little ants may be observed to issue from the 
mines with the old ones and loiter around the entrances as if as 
yet unable to take part with the stronger ants. 
Here and there among the mass of workers, perhaps forming 
about one per cent of the total number, may be seen a much 
larger, formidable-looking ant with enormously swollen triangu- 
lar head, which takes no part in the work, but always accom- 
panies the “ worker minors,” as they are called, on their expedi- 
tions. I spent much time trying to find out the functions of these 
large-headed ants, but failed to get any clear notions as to the 
part they play in the politics of the commonwealth. They may 
nearly always be seen on a bit of stick or other eminence, caress- 
ing now and then the antennz of the passing ants with their own. 
Talking, we may suppose, in ant language, since it is well estab- 
lished that ants are, by means of their antenne, able to commu- 
nicate their ideas gne to another. It appears to me that these 
apparently useless ants directed in some way or other the move- 
ments of their working sisters. Bates in his Naturalist on the 
Amazons, came at first to the same conclusion, but afterwards 
abandoned this idea for one I think not more tenable, namely, 
that these ants by their superior size draw upon themselves the 
attacks of ant-eating birds, &c., being thus, as he terms it, merely 
“ pieces de resistance,” thus only serving to preserve the main 
body of workers by a self-sacrifice of mere “ passive” resis- 
tance. ; 
went to the trouble to shoot several ant thrushes and Den- 
a ema aa eee 
