1960] Evans — Bembix u- script a 53 
leading to them had been filled and hence could not be traced accurate- 
ly. Because of the close proximity of nests in this colony, it is im- 
possible to be certain that all of these cells belonged to the nest in 
question. The evidence now seems strong that the nest is usually 
closed after the completion of only two or three cells. It is not im- 
probable that one-celled nests also occur, perhaps also four or five- 
celled nests rarely. Two or three-celled nests are characteristic of 
Bembix nubilipennis (unpublished observations), while B. cinerea and 
B. belfragei characteristically make one or two-celled nests (Evans 
1957 ). 
Fig. 2. — Typical three-celled nest of Bembix u-scripta (our field note no. 
1635, Rodeo, N. Mex.). Cell a contained a completed and hardened cocoon, 
so was obviously the first cell of the nest. Cell b contained a fresh, still soft 
cocoon; cell c was a new cell which was empty when the nest was dug out. 
The figure on the left shows the nest in lateral view, compressed to a single 
plane, while the sketch on the right shows the proper relationship of the 
cells in a horizontal plane. 
I he cells of a given nest are normally separated by several centi- 
meters of soil. After the first cell is fully provisioned, the bottom .3 
to .5 of the burrow is packed tightly with sand. 1'he wasp then con- 
structs another section of burrow of about equal length at roughly a 
90° angle with the main burrow and builds the second cell at the end 
of it. The third cell-burrow and cell are normally constructed from 
the opposite side of the main burrow (fig. 2). 
Provisioning. — During the first two days of study, we were unable 
to find females provisioning their nests even though the nests which 
we dug out usually contained fresh flies. We left the area on these 
days at 1600-1700, a time when most digger wasps have completed 
