X. EXPERIMENT ON THE SENSE OF DIRECTION OF CER- 
CERIS FUMIPENNUS. 
The Sense of Direction of animals, particularly of Ants, Bees, 
and Wasps, is a subject which has engaged the attention of many 
naturalists. From my own observations on social and solitary wasps 
I incline to the opinion that these are guided mainly by sight in 
which familiar objects in the environment of their nests are im- 
portant factors. 
A rather decisive evidence of the important role played by trees, 
bushes and other objects in the orientation of insects is afforded by 
the actions of one of my friends, Cerceris fumipennis. On October 
24th I discovered her bearing a, weevil ( Chonotrachelus neocrataege) 
into her nest, which was situated on the edge of a five-foot embank- 
ment just under a bush some two feet high. The next day I re- 
turned, cut the bush off at the roots and placed it three feet to the 
right. Soon fumipennis , too, returned and flew, not to her nest 
but to the bush which I had placed to one side. After discovering 
her mistake she flew away to get another start, came down again 
from between two trees and flew to the bush. Since she repeated 
this performance at least a dozen times without finding the nest, it 
is safe to conclude that it was the bush which directed her flight. 
Moreover, the wasp always flew down from the same direction, show- 
ing that earlier in her course she was directed by other objects, es- 
pecially trees. This latter observation I have several times made' 
on wasps whose nests I destroyed before the owners had completely 
stored them. 
As a matter of fact, the power of finding their way is not so per- 
fect as one might be led to suppose. Many spider-ravishers have 
great difficulty in finding the spiders which they hid or hung up 
while digging their nests. I have seen individuals of Bembex tex- 
dnus and Monedula Carolina so far lose track of their nests as to 
fail entirely to find them again. 
In view of these and other facts I should agree with the Peckhams 
in the opinion that wasps have no additional sense, the sense of di- 
rection, in the common acception of the term, nor that they find 
their way by a process of dead reckoning as Darwin suggested, but 
that they find their* way by a detailed familiarity with objects near 
the nest and by a general acquaintance with the locality in which 
they pass their lives. 
