II. AMMOPHILA PROCERA, DAHLR. 
Ammophila is perhaps the most famous of all the digger wasps. 
Her homing faculty is most wonderful and is perhaps mainly re- 
sponsible for the assumption of the sixth sense in insects, the sense 
of direction ; the accuracy of her stinging instinct was long regarded 
as perfect. She has been several times observed to use a pebble 
as a tool with which to tamp the ground, so that a claim for 
her superior intelligence will not easily be contradicted. She is, 
moreover, a delightful subject for observation because of her tol- 
erance of human company as well as her easy grace and her calm 
and dignified, though business-like ways. 
In the course of the summer I was fortunate enough to observe 
six different individuals of Am. at work, four of which allowed 
me to witness the carrying home and storing of the caterpillars, 
while two individuals performed for me the whole process of dig- 
ging, storing and closing up the nest, leaving me in the dark on 
only one step of the process, namely, the capture of the prey. All 
the individuals observed belonged to the species procera. It in- 
cludes the most formidable members of the genus in America. The 
species is very variable in size. Five of the specimens whose ac- 
quaintance was made were among the largest; the sixth was much 
smaller and differed from the others in the number of caterpillars 
captured, as will be seen below. In the present description of 
Ammophila’ s habits, I shall follow the whole history of a nest 
-from the beginning. 
When Ammophila feels the necessity for doing so, she flies around 
in search of a suitable place to dig her nest. She is hard to satisfy 
in this respect, for I have seen her alight at a dozen different places 
and begin to dig before she finally decided on a place as good 
enough. To test the ground she does not waste time by digigng 
long at any one place, as does Pompilus ,- which often abandons six to 
eight half -finished nests before deciding on one to suit her; but 
Ammophila merely scratches the surface a little and, if dissatisfied, 
flies or runs off to another place. Some over-fastidious indi- 
viduals have been known, however, to abandon the old nest and dig 
a new one near by after the former or even the ground around it 
had been slightly disturbed. 
After the location has been chosen, Ammophila does not waste 
