Field Studies of the Non-Social Wasps 329 
work in the dark gallery, but they do not open up their 
doors, which are closed each night, until the sun is high 
and hot in the summer sky. This statement implies that 
they sleep in their burrows, and so they do; at least the 
females of the population which possess burrows sleep 
there; I have not yet been able to find, by careful scrutiny 
of the vicinity, where the males find their night’s lodging. 
I have never yet seen the males enter the burrows, 
although they are frequently to be seen pursuing the fe- 
males as they come and go. They are small and agile, 
and difficult to apprehend. The sexes are so different in 
appearance that they look like two different species, the 
female a large, reddish-colored insect, and the other 
much smaller and yellow. Mating occurs on the wing or 
while the home-maker goes to and fro about her work; 
no special frolic or festival has been observed to accom- 
pany this function, such as occurs in several species of 
wasps. 
The owners of the burrows come home and enter the 
nest early, about 3:30 to 4:30 o’clock, and push up a 
plug of loose earth to close their door snugly for the 
night. This roof remains in position remarkably well, 
in spite of the fact that it is so soft that it will collapse 
if tickled with a straw. On one afternoon when a shower 
occurred early, I visited the colony and was surprised to 
find that even at that time of day, which is usually the 
wasps’ busy hour, these good housewives had all hurried 
home to shut up the house before the storm broke; every 
door of the fifty or sixty nests was closed from within! 
In covering the hole the wasp backs up with the ab- 
domen extended straight and the load of earth under 
the abdomen and behind the legs. Thus she pushes the 
load up to a point 14 inch from the top, where she presses 
the dirt against one side of the hole. Thus she brings up a 
