376 Trans. Acad, Sci. of St. Louis 
eolored cocoons in the loose mass of debris. For the fill- 
ing the mother wasp utilizes whatever material is con- 
venient. The first few nests that I found happened to be 
near the railroad track, and the builder had picked up 
small cinders and filled her nest with them—rather an 
unusual expression of mother love, to pack her tender 
babe’s cradle with nice soft cinders! If these had been 
the only nests found, I might have said, like the blind 
man seeing the elephant, ‘‘They fill their nests with 
cinders.’’ But soon I was wondering just what they did 
before the advent of railroads and cinders in this region, 
and presently I found an explanation; other nests were 
filled with other materials, tiny clods, some of which 
had been put in hard and dry, and some moist enough 
that they had stuck together, loose dirt, bits of bark, 
splinters of wood, fragments of leaf or stem, seeds, 
grass-heads, tiny pellets of insect excreta, disc-florets of 
composites, ete. Two or three burrows were neatly 
closed at the top with several wild-oat seeds stuffed in 
side by side with awns protruding. 
Upon opening the cocoons of this species early in J uly 
I always found adults therein fully formed; hence I 
always wondered if the insects were ready to emerge 
when I broke into the cocoons or whether they would 
remain in their fully formed condition until some later 
date, or even until the following spring. An elder twig 
taken at Meramec Highlands on July 6 showed that the 
wasps do emerge about this time, for between July 12 
and 22, five adults left their cocoons by biting out a little 
dise at one end. Several others which emerged from 
their twigs in the laboratory appeared between May 28 
and June 20, but their development may have been accel- 
erated by their stay in the house during the cold months. 
