1934 ] 
Notes on Megarhyssa lunator 
239 
there is no mad rush for union with the female. Sometimes 
there is a mild contest between two or three individuals; 
more often only one male reaches the female. He rests upon 
the back of her abdomen which he clasps with his legs. He 
then flexes his abdomen ventrally, forming thereby a flat 
spiral. In this position the extreme tip of his abdomen, in 
an inverted position, is directed toward the corresponding 
free or caudal end of the female abdomen. The penis, the 
median of the three terminal appendages of the male (the 
others are claspers) thus enters the genital opening of his 
mate in a posterior direction; a condition made necessary 
by the peculiar fact that the female genitalia open ante- 
riorly. 
Mating requries only a few seconds: at the end of that 
time the female dislodges her mate by backward thrusts of 
her posterior legs. 
It does not seem likely that the female Megarhyssa ever 
again requires the attentions of a mate. Males ignore all 
but emerging, and hence virgin, females. Moreover, since 
the female possesses a definite spermatheca, it is probable 
that she, like other Hymenoptera, carries with her the sperm 
necessary for the fertilization of eggs. 
Oviposition 
In spite of the generally accepted conclusion that Megar- 
hyssa deposites her eggs by drilling through solid wood, my 
own observatons contradict this claim. Of literally hundreds 
of ovipositing females observed, not one could be said to drill 
in the true sense of the word. In cases where this appeared 
to be true a judicious prying off of the overlaying bark re- 
vealed that the ovipositor had penetrated a crack in this 
same bark and entered the end of an open burrow. Where 
bark had already been stripped from the tree, individuals 
were often seen inserting the ovipositor directly into an 
open burrow. 
It is of course possible that the female Megrahyssa may 
drill through, the bark to a burrow. It is also possible that in- 
dividuals may take advantage of openings made by an ovi- 
positing Tremex. As long ago as 1794 Marsham observed 
this kind of behavior on the part of Ichneumon manifestor. 
