Field Studies of the Non-Social Wasps 413 
iar with the process. But it seems to me that, as men- 
tioned above, when she transfers the method to a new en- 
vironment and circumstances, she has gone beyond pure 
instinct and, with an instinctive inclination toward 
pounding, she has broken the chain of instinct and used 
a grain of something akin to reason. After the spider 
had been laboriously forced into the burrow, the male 
blithely followed in after. 
Since the male follows the female in entering the bur- 
row, he is the first one out, with the female following im- 
mediately after him. She flies directly away about her 
business, while he returns to the opening, turns around 
and creeps in backward. 
The male is a good watch-dog. I have never chanced 
to see a parasite attempt to enter the burrow, but I 
have often seen other J. clavatum try to intrude. On one 
oceasion, when the little watchman had an exceptionally 
difficult task to keep out another male, he eventually got 
the impostor by the back of the neck and actually threw 
him out, with quite a scuffle in the air before one entered 
the burrow again; but whether it was the owner or the in- 
truder that returned I do not know, since their identity 
was lost to me in the fight. Not to be outdone, the van- 
quished one returned after a few seconds, but even before 
he could put his foot in the doorway, the occupant flew out 
and chased him some distance, quickly resuming his place 
on guard. This probably was the original occupant, for 
soon after, when the female returned, she was greeted 
with calm familiarity and entered with the usual cere- 
monies. A half hour later, this or another rival again 
disturbed the peace of the home, but the owner at once 
flew menacingly at him and promptly put him to rout. 
It is not alone the males who try to gain access to the 
nests of others; the females, for reasons which I have 
