74 
Psyche 
[June 
there was found a typical ball of pollen, as had been present in 
all of the rest, but no signs of an egg or larva. 
Some of the chambers for the young bees, i. e. numbers 1, 
2 and 3 in Fig. 1, were but a centimeter from the surface. At the 
time of my chiseling these out, I saw on their walls patches of 
pollen of the same size as the loads on the hind legs of the fe- 
males. Here, the bees were apparently forming a supply of 
pollen before shaping it into a ball for the young embryo. The 
walls of these chambers were smoothly lined with a mud-like 
material. 
Between the cells containing the larvae the tunnel was 
filled up with loose sand. This was somewhat damp and more 
darkly colored than the surrounding stone This probably pre- 
vents certain enemies from reaching the young bees, during the 
hot summer months of July, August and September when the 
builders of the nests are dead. 
In cells labeled 4, 5, 6 and 7, Fig. 1, one sees the stages in 
the development of the young embryo. Thus, in cell 4 there 
was a large, well-grown larva, without any visible pollen. 
But in cell 5, the larva was not so well developed, having eaten 
but half of its provision of pollen and honey. The egg for this 
one had been laid later. Further along, in cell 6, a large ball of 
pollen, 2.5 mm. in diameter was present. On its side there was 
a slightly developed larva, just out of the egg. And finally, in 
cell 7, there was a similar ball of pollen with an egg along the 
side. One end was inserted into the pollen. Apparently it, had 
just been laid. This latter chamber is shown in Fig. 2. The 
egg of this species is somewhat crescent-shaped, quite smooth, 
Fig 2. — The egg of the species is crescent-shaped. (Taken from Fig. 1, cell 7). 
