118 
LOCK : ECOLOGICAL NOTES 
occasionally seeds were carried away from the nest One of 
these was dropped about three feet away. A few minutes 
later it was picked up by another ant of the same family and 
carried into the nest. Another seed was carried away for 
three or four feet and then back and into the nest without 
having been dropped. Occasionally also seeds found at a 
distance from the nest were carried a little way and then 
dropped. Sometimes an ant coming from the nest would 
examine one of the seeds I had placed close to the opening 
and then hurry away without picking it up. But the great 
majority in all cases were safely carried into the nest. 
The most frequent species of ant upon the plant itself was 
Camponotus mitis, Smith. This form seemed to be chiefly 
attracted by the extra-floral nectaries upon the bases of the 
leaves, and did not appear to take so much interest in the 
seeds, although occasionally carrying them away. One or two 
members of this species were usually to be found upon every 
branch of the plants. I was not able to discover whether 
they were “ of use ” in keeping off invaders. Other insects 
were certainly very rarely found upon the branches. On the 
other hand, Camponotus did not appear at all pugnacious 
when disturbed. 
That the aril is the attractive part of the seed was well 
shown by the ravages caused by another ant—apparently 
an undescribed species of Sima—upon some seeds which I 
had kept in a paper bag in the laboratory. This species was 
too small to carry off the seeds, and accordingly I found the 
arils eaten into and reduced to powder and a great part 
carried away, the seeds themselves being uninjured. The 
arils of the ripest seeds were most eaten. Another small 
ant, whose name was not ascertained, carried off upwards of 
200 seeds from a table in the laboratory during the interval 
of two hours at midday when I had left them unprotected. 
It appears fairly certain from the above observations that 
a principal mode of distribution for the seeds of this plant 
is by the aid of harvesting ants. Ants carry away the seeds 
and sometimes drop them, and in this case they may easily 
