94 
against the edge of a level slab of smooth concrete, so that the circular 
area over which the ants deposited their excavated soil was divided 
into two parts; one extended over a flower bed, the other over a sur- 
face of cement. 
Every day the concrete slab is swept, so that on any given morn- 
ing the loose earth is exactly half of the total amount brought up 
during the preceding night. On January 24, 1911, the radius of the 
circle of debris was 7 feet, 4 inches. The night had been calm, so 
that in sweeping up the deposit I am sure that I collected no wind- 
borne particles. The weight was 23.6489 grammes, and by doubling 
this figure we get the total output of loose dirt for the night. When 
poured into a cubic inch measure it almost exactly filled it. Under 
favorable conditions, therefore, these ants can excavate nearly two 
cubie inches in a night. During a colder night, a few days previous, 
the radius of the circle was only 4 feet 8 inches. Quite early in the 
evening, some ants will be seen travelling to the very circumference 
of the circle, passing by bare spaces where we might imagine they 
would be perfectly justified in getting rid of their load. 
Prof. Wheeler, in speaking of repletes, remarks that they ‘‘are 
of course imprisoned for life’’; but I have found my ants gradually 
resume their original figure when their contents are exhausted. In 
the nest I excavated November 6th, 1910, there were two or three 
dozen semi-replete majors whose gasters were no larger than those of 
the fertile female’s and who could walk about quite freely. Others 
had apparently been entirely emptied, owing to the lapse of time 
since the spring honey harvest and their gastric segments were in a 
distressing condition of misfit. They did not overlap smoothly, but 
Fig. 6. Replete major of Myrmecocystus mexicanus unable to regurgitate honey 
while hanging, and who has to assume a recumbent posture before she 
can feed her sister workers, 
were warped and twisted out of shape. But another course is open 
to a replete who finds her honey content diminishing. She may 
swallow atr and thus maintain her size. (Fig. 6.) This is done by 
both M. M. Mojave and the present species. In my artificial nest I 
found a full-sized major replete three-quarters full of honey, and 
