Insects Bred from American Larch 69 
Some interesting observations upon the breeding habits 
were made by Mr. A. J. MacNab, a graduate student in the 
laboratory, and these are supplemented by other observations 
made by the senior author at various times. On February 1 
some branches from a tree which had been cut the preceding 
winter were brought into the laboratory and placed in a 
breeding cage. On March 7 adults of M. scutellatus began 
to emerge. Some fresh pine from one to two inches in diam- 
eter, was placed in a breeding jar and the beetles were 
introduced, the bottom of the jar being covered with a layer 
of moist earth for the purpose of keeping the humidity more 
constant and to furnish a suitable footing for the beetles. 
When this jar was placed in the sunlight, or when the 
bright light from a tungsten bulb was directed upon the jar, 
the females climbed to the top of the pine sticks and made 
attempts to fly. They were followed by the males, all of the 
beetles showing apparent excitement. After being exposed 
to the heat and light of the tungsten bulb for about an hour, 
copulation began. In this process the male mounts the 
female, grasping her around the prothorax with his fore- 
legs, which are especially modified for this purpose, at the 
same time bending his abdomen downward and forward so 
as to bring the genital openings together. The penis is then 
extruded and sexual connection is established if the female 
denotes her willingness by opening the space between the 
last dorsal and ventral plates of the abdomen. When she is 
not ready for sexual intercourse, she often tries to escape, 
and sometimes an especially ardent male may be carried all 
over the limb for ten or fifteen minutes before the female 
becomes complaisant or until he is dislodged. 
Copulation lasts a variable length of time. In several cases 
where the time was noted, it lasted from half a minute to 
considerably more than three minutes and was accompanied 
by a pumping movement of the abdomen of the male. The 
same male often copulates with the same female or with other 
females repeatedly. In one case, after a union lasting over 
three minutes, the connection was broken, but the male still 
clung to his mate and was dragged or carried all over the 
