148 BuUetin Wisconsin XaturaJ History Society. [Vol. 6. Xos. 3-4. 
place being unsuited to her taste, liies along the bank in arcs 
testing in like manner every few inches until her fastidiousness 
is satisfied as to the character of the soil. Usually the spot 
chosen is at the base of a tussock of vegetation though she is not 
averse to a level expanse of sand, the edge of a small stone or the 
base of a four inch cliff. 
Having decided on a location the wasp begins the actual labor 
of excavation and herein again lies a peculiarity which, as far as I 
l?ave obser\-ed, is characteristic of Anacrabro as opposed to other 
digger wasps of this region. She bites off a piece of earth and 
flying backwards from six to eighteen inches, drops it and dives 
forwards again for more, this to and fro flight taking place very 
rapidly and with great regularity without the insect turning about 
in its excursion — in other words, the insect always faces the nest, 
the backward flight being started by a backward jump from 
the ground and is not accompanied by an audible hum. The 
groimd is not thrown but dropped, the momentum of the flight 
and its sudden termination being sufficient to transfer it in para- 
bolic curve to some distance from the nest, in one case showers 
of sand falling over my book as I wrote though fully three feet 
from the nest. In no case was the insect seen to assist in the 
loosening of earth by scratching. Having penetrated to some 
distance the method of approach, or rather the rythm, is altered 
in that it at times becomes jerky in character. One, two or even 
three momentary halts, each one nearer the entrance may be made 
before the wasp disappears within. The purpose of this man- 
oeuvre appears to be to assure an accurate entrance into the nest 
as in no case was the wasp seen to alight and enter by crawling. 
]n one case in which the nest was located at the foot of a cliff 
and the entrance gallery almost paralleled its base, the insect 
repeatedly struck the side just within the door, often with such 
force as to send her rolling down the bank. Again and again she 
flew back to renew the attempt each failure being accompanied by 
an angry buzz and with every appearance of great annoyance. 
Discouraged at last by the frequent repetition of this mishap she 
abandoned the nest after tunnelling about one inch, the intel- 
ligence of the insect evidently being not great enough to overcome 
the difficulty. That this method of entering the nest is instinctive 
was shown in practically all cases. Especially evident did it be- 
come on one rather windy day. The wasps were repeatedly 
blown from the straight path to the nest generally missing the 
opening by a verv* short distance. It certainly would have been 
far easier to alight and walk into the nest, always less than half 
