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Psyche 
[June-Sept. 
a replacement of thickened portions of the paper over and 
between the bottoms of the cells. The true thickness be- 
comes apparent at once in a vertical section where it can be 
seen as a paper-thin, yellowish deposit between adjacent 
cells. 
Although Bequaert and Carpenter reject my specimen as 
the comb of a wasp nest, they do not, as stated, deny that it 
is a fossil. However, they offer no suggestion as to its prob- 
able identity except to point out a resemblance to nests 
called Uruguay auroranormai described by Roselli. 4 It 
appears from Roselli’s description that these nests were 
taken from Cretaceous strata in Uruguay, but the evidence 
is not clear that they were made in Cretaceous time. How- 
ever this may be, the resemblance between Celliforma favo- 
sites and Uruguay auroranormai is only superficially sug- 
gestive. The cells of both nests are arranged in parallel 
rows in three different directions. Those of U. aurora- 
normai are larger, and it is quite evident from Roselli’s fig- 
ures 19, 20, and 31, that the cells are separated from one 
another by matrix approximating in thickness one-third 
the diameter of the cells. In C. favosites the cells, as stated 
before, are separated from one another by a thin deposit of 
paper thickness only. Roselli’s figure 20 shows one cell that 
displays a spiral seal, 5 a circumstance which indicates 
strongly that the constructor of the cell was a mining bee 
rather than a wasp. 
For the reasons given I am not convinced that the 
Bequaert and Carpenter arguments rule out the possibility 
of a vespine, or in broader terms, a social hymenopterous 
origin of the fossil. I would, however, make it clear that 
I am open-minded on the issue and am ready to accept satis- 
factory evidence, no matter what the result may be. 
4 Roselli, F. Lucas. Sohre insectos del Cretaceo del Uruguay o des- 
cubrimientos de admirables instintos constructivos de esa epoca. 
Boletin de la Sociedad Amigos de las Ciencias Naturales “Kraglievich- 
Fontana”, tomo 1, num. 2, pp. 72-102, 1938. 
5 Brown, Roland W. Celliforma spirifer, the fossil larval chambers 
of mining bees. Jour. Wash. Acad. Sci., vol. 24, pp. 532-539, 1934. 
