OCT. 1906. OUR KNOWLEDGE OF THE VISUAL MEMORY OF BEES. 
141 
August 15. 
At 9 a. m. the nest is still closed, although the weather is 
bright and warm. At 9 :20 our old acquaintance Argyroselenis, 
easily recognized by the bright red mark, arrives, inspects 
the nest, and, as usual, takes up a position on a small plant. It 
waits until 10:18, but the nest has not yet been opened, and it 
flies away. Every once in a while it returns, examines the nest- 
entrance, and alights on a neighboring twig or leaf, remaining 
motionless for many minutes at a time. 
August 16. 
An examination of the nest showed it to be completed and 
closed definitely. This had undoubtedly been the case the 
previous forenoon. Nothing more was seen of Argyroslenis, nor 
of Colletes the owner of the nest. 
It is quite evident that after having discovered the nest this 
parasitic bee pursued a course similar to that of a host-bee when 
constructing a nest. It started out to make a careful and re- 
peated inspection of the environment of the nest, gradually cover- 
ing more territory in different directions, but often returning to 
the nest as the main object of its attention. Being possessed of 
a good memory for visual impressions it became acquainted with 
the locality within 6 minutes, and experienced no difficulty in 
refolding the nest at its next visit after an absence of 14 minutes. 
It gradually acquired a thorough familiarity with the topography 
of the region, and on its return to the nest it was seen to fly 
towards the opening as directly as the owner itself. 
Such a parasitic bee when hunting for a nest of a host-bee is 
not always flying around in a haphazard way, trusting to its good 
luck in finding a nest here to-day, and one somewhere else to- 
morrow. When it has come across a suitable one it is very careful 
to keep this under observation, and in making its trips to and 
away from the nest it is directed by its visual memory in exactly 
the same manner as the host-bee itself. It would not be in the 
interest of such a bee to pursue a different course. The work 
of the host-bee in constructing a cell, and providing it with the 
food-supply must have progressed to a certain point before the 
parasitic bee may find it suitable for the reception of the latter's 
