372 Trans. Acad. Sci. of St. Louis 
walked out of the stem, a handsome adult female. Thus 
the life cycle from egg to adult for this insect was twenty- 
one days. 
Another twig was examined which was taken at Tower 
Grove Park on April 27. When the twig was cut open, 
an adult popped out; it was replaced in the cell and 
strips of mica were sealed over it. The twig had a 644- 
inch tunnel and 7 cells. The upper 3 inches of the 
channel were vacant, 2 of the cells were empty and the 
remaining 5 were occupied by black adults. From here 
they did not emerge until May 2; then they worked their 
way out of the cells by kicking the filler back of them, 
the upper ones emerging first, and the last following 
them on May 5. 
One other elder stem was found on July 4, 1918, to 
contain an adult wasp, D. biparitor; this was in all 
probability a new one just emerging. When the twig 
was split, three others were found which had the wings 
spread and were all ready to come out. The twig was 
a large one, as usual, one-half inch or more in diameter, 
and the tunnel, which was barely one-eighth inch in 
diameter, oscillated to the full extent of the pith-cham- 
ber, and sent off ramifications or side pockets which 
served as cells. The terminal cell, at a depth of eight 
inches, contained an almost full grown cuckoo-bee and 
some remains of plant-lice. The second and third, sev- 
enth and eighth cells were all filled with plant-lice, in a 
mummified condition; evidently no egg had been laid 
with them, or if deposited it had not hatched to consume 
them. These cells contained each 25, 26, 22 and 25 
aphids, respectively, all of the apterous form of Rho- 
palosiphum rhois [J. J. Davis]. This is not the first 
Diphlebus mother which exhibited such astonishing pre- 
cision in ‘‘counting out’? about 25 aphids to each cell. 
