108 
PROCEEDINGS OF THE NATURAL [April, 1887. 
. Being now satisfied that the wasps distinguished colors and 
were disturbed by a change from one color to another we en¬ 
deavored to determine more exactly how strong was the impres¬ 
sion which a color made upon them. 
On returning to the nest the wasps usually approached from 
the southwest, west or northwest. On August 13, after the red 
paper had been over the nest for twenty-four hours, we substi¬ 
tuted a blue paper, moving the red a foot and a half to the 
south. As the ground was covered with grass both papers were 
slightly raised. Our object was to see whether any of the re¬ 
turning wasps would enter the hole in the red paper, to which 
they were accustomed, instead of going to the hole in the blue 
paper which was above the entrance to the nest. For con¬ 
venience we shall speak^ri the blue as the true, and of the red as 
the false entrance. In this and in the subsequent experiments, 
when it was possible, both of us sat close to the nest-^ne count¬ 
ing the wasps that went into the true, and one those that went 
into the false entrance. When only one of us could be present 
three successive counts were made, taking the same length of 
time for each ; first, of those that entered the false hole ; second, 
of the entire number that entered the true, and third, of those 
that entered the true without hesitation. 
, ^ ten minutes (9=35-9:45 a. m.), after we had substi- 
u e e blue paper for the red and moved the red to one side, 
76 wasps went in at the true entrance of which 54 fhrt homed 
"7* 1 “ ab ™‘ l>»lf of them actually entering and erpl.r- 
rng the grass beneath. Several, not finding the entrance here, 
flew away entrreiy. Moat of those that flew directly in., the 
™ “‘"T °“" e from *•“ northwest and therefore did not 
pass above the red paper. 
From 9:45-9:52 of 78 wa*™ sn a ^ 
and afterward found the to” 10 ““ 
in“Ml:r° nrS , W rr W B ‘ e " again hr ,.nnut. 5 s .Jov- 
rng winch tune out of 125 wasp. 1 6 wete deoeived 
wished to lleThThLr^veTlh” ^ “ T 
waapa to become thorough,, famiij 
