196 
Psyche 
[December 
In placing a pebble in a crevice or on a resin extension, the pebble 
was turned and rearranged, by means of the legs and abdomen, 
much as a mason fits a stone into place. The pebble remaining, 
the bee placed resin on its free edges and another was brought. 
Sometimes when a pebble did not fit into place, the bee tried it 
all about the edge of the cell in an attempt to get it to hold. 
After a few trips to the cell under construction, the bee was 
seen to carry a pebble and place or fit it onto the general surface 
of the outside of the other cells, mainly in the depressions be- 
tween them. This helped to break the outlines of the individual 
cells and make the surface more even, as well as make the walls 
thicker and the protection greater. Another nest of this bee, 
also found at Owens’ Lake during this period, showed consider- 
able thickness of resin and pebbles placed after the cells had 
been made. Old nests, from which bees have emerged, often 
show little or no trace of individual cells, probably due to the 
heat making the resin soft and allowing the material gradually 
to settle. 
The contents of the cells, of the nest observed, were examined 
on September 26, with the following facts noted. A cocoon 
was found each in cells 1 and 3; but larvae in 4 and 5. Number 2 
contained much pollen and a small dead larva. The lower end of 
the first cell had been closed with a layer of pebbles and resin about 
one millimeter thick The upper end of the inner space of the 
cell was filled with a cocoon, surrounded with pellets of excre- 
ment; the lower part contained a space partly filled with ex- 
crement. The cocoon possessed a very distinct mammillary 
projection which extended downward. The head of the larva 
has always been towards this point. 
The length of a typical cell has been found to be 15 mm. At 
the end opposite the location of the orifice the mass of pollen, 
filling the cell for a distance of 5 mm., is stored. The remaining 
10 mm. of space is at first empty; later, when the larva has 
developed, part of the space is filled with the cocoon and part 
with excrement. 
On October 3, the larva of cell number 4 had a fully formed 
cocoon which had been started October 1. The mammillary 
point first consisted of a round hole, with a white outer surface 
