238 
Psyche 
[December 
NOTES ON MEGARHYSSA LUNATOR 
By Cyril E. Abbott 
Morgan Park, 111. 
For several years I have had the opportunity to observe 
rather closely the activities of Megarhyssa lunator, and 
have discovered some curious, and apparently hitherto un- 
known peculiarities of behavior. 
Emergence of Adult Insect 
In view of the fact that the adult virgin female is found 
in a burrow opening just beneath the bark, as well as from 
the fact that this burrow must be enlarged to permit emerg- 
ence, it seems likely that the larval Megarhyssa pupates near 
the surface of the tree. The insect is enabled to escape by 
biting bits of wood from the walls of her prison. In all ob- 
served cases the overlaying bark had been removed by the 
observer. No doubt the insect is capable of gnawing 
through the bark ; at least a virgin female imprisoned in a 
cloth sack in an effort to attract males chewed her way to 
freedom. 
The emerging female is much disturbed by suitors, which, 
having gathered in numbers about her burrow, insert their 
abdomens into the opening. In some cases a male becomes 
so firmly wedged into this opening, clinging meanwhile with 
his claws to the bark, that he is removed with difficulty by 
the observer. 
The details concerning emergence of the males have not 
been observed. The openings from which they leave the 
tree have an average diameter of 2.27 mm., those of the 
females 4.30 mm. 
After enlarging the opening of the burrow the female in- 
sect rests for a few seconds. She then crawls out onto the 
surface of the tree. 
Mating 
In spite of the ardor of the male insects (see Riley, 1888) 
