116 
Psyche 
[June 
this all-night work was not an unusual occurrence among ants, 
I made casual inspections of a nest of Crematogaster lineolata 
at Black Mountain, N. C. These inspections, made around 9 
o’clock in the evening, never revealed under my flashlight more 
than a half-dozen ants wandering about on the flagstones near 
the nest. Their comparative scarcity may be accounted for by 
the fact that the weather was cold at this station. 
After August 14 I attempted to discover other night-working 
species at Durham. At 10 p. m. of that date I detected two or 
three individuals of the small black ant Monomorium minutum 
var. minimum Buckley gathering dry grass seed. I subsequently 
baited several spots with honey. During the day this soon at- 
tracted Monomorium as well as a dozen or more individuals of 
the large brown ant, Formica 'pallide-fulva Latreille. 
I then made an examination in the early morning, before 
daybreak, and at the baited stations found only Monomoriums. 
A further search of the locality, however, revealed the little 
black ants milking aphids on the tender shoots of an apple tree. 
The heart-shaped Crematogaster species was also found harvest- 
ing grass seed, but though extensive search was made, none of 
the Formicas could be found, nor have I yet found any of this 
species working at night. 
Observations at Durham were then suspended until Sep- 
tember 2, when at 8 p. m. the working line of the Crematogasters 
was still found to be operating in full force. On September 3 
(8. a. m.) the line was straggling, there were fewer individuals 
working and I observed for the first time what might be called 
sleep on the part of these ants. In a section of the line 7 feet long 
I observed that there were now only thirty ants, hardly a fourth 
of the number observed on other occasions. Six of these were 
apparently sleeping but were probably not totally unconscious, 
or if they were, were easily awakened. As the line of march at 
this point traversed the under side of a floor the ants were travel- 
ing with their backs toward the ground. The resting individuals 
were motionless, with legs and antennae tucked in, but when ap- 
proached by passing workers for the usual kissing salute the 
dormant ones immediately held out their antennae and a passerby 
