330 Trans. Acad. Sci. of St. Louts 
few more loads, condensing and packing the earth against 
one wall; then she brings up more dirt to close the re- 
maining aperture. Even then she does not stop, but adds 
many layers to the plug from the inside; we are made 
aware of this by the movement of the plug as it heaves up 
with the vigorous pressure from underneath as each load 
is packed in place. In many cases the wasps seem to 
deem their day’s work done at 4 o’clock, and by 6 most 
of the holes are partly or completely closed for the night. 
It is a pretty sight in the morning to see the wasp first 
venturing out. The granules of clay covering the hole 
quiver and part, the head appears, and the opening is 
silently made wider. Then the wasp pauses to peer cau- 
tiously about (fig. 31); this habit of cautious recon- 
naissance is a very characteristic gesture of this species. 
She creeps so stealthily to the edge of the hole that one 
is hardly aware of the motion, and pauses with her face 
at the aperture and peers about with a gaze so intent 
that one can almost feel it; if she is not satisfied that all 
is safe, she drops stealthily back; if all is well, she darts 
away like a flash, leaving the burrow wide open. She has 
retreated thus when I moved noiselessly at a distance of 
4 feet; this would indicate that her range of vision en- 
compasses at least that distance. Upon returning home, 
she seems to have no trouble in locating her burrow, al- 
though it is one among so many all alike, in the roadway 
or in the sparse grasses nearby. She does not loiter, 
but plunges headlong into the burrow, almost before one 
has time to get a good view of her. Sometimes she circles 
about on the wing a few times before she seems to get 
her bearings to make an accurate descent directly upon 
her burrow. 
Every observation upon the Cerceris raui population 
at Jerseydale indicated that this wasp uses only two 
