396 Trans. Acad. Sct. of St. Louis 
of the material splashed against the wall. This series 
shows the last vestiges of what was once probably the 
important habit of cocoon-making. By April 12 the three 
lower ones had arrived at the pupal stage; the upper 
one had died of its injuries. On April 26 the condition 
was precisely the same. By May 1 these pupae still were 
yellow, but their eyes were pigmented; by the 12th they 
were all black. They could not be examined again until 
May 26, when it was found that in the interval all had 
attained complete development, but for unknown reasons 
all had perished without breaking their walls. 
Another sumac twig harboring this same Odynerus 
was found in the same park on February 12, 1920. The 
hollow in the twig was 4% inches deep, and contained six 
large, roomy cells with six fat and thriving pupae. The 
mother of this brood left a record of her individual tem- 
perament, in contrast to nests heretofore examined, by 
making cells of various sizes, from 1% to 1 inch in length. 
The partitions varied from 14 to %4 inch, and each one 
was constructed of two layers, but these two layers 
touched each other, with no free space between. The ma- 
terial from which they were made was the debris which 
had formerly adhered to the walls, and which had been 
scraped off clean and kneaded into a mass. In one par- 
tition made of these scrapings was a perfect brown co- 
coon of a parasitic wasp imbedded firmly in the pulp. 
This shows how little regard the wasp paid to parasites’ 
cocoons when she needed building material. This cocoon 
was not injured and later gave forth a good adult. Some 
of these wasps had the aforementioned remnant of co- 
cooning substance in a sheet stretched over the head, 
and in some this material had been dissipated while still 
liquid on the walls. In three of the cells, behind each 
occupant was a pretty spiral curlyqueue of thin, papery 
