1941] 
Antiquity of Social Insects 
109 
246, 248, and 249 in Duncan’s 3 recent publication on vespine 
wasps. Irregularities such as tapering and curving of the 
bottom portions of the cells is common around the margin 
of the comb, and probably varies considerably with differ- 
ent species. Sections cut carefully along a row of cells 
through the central part of a comb usually show as much 
regularity of cell bottom arrangement as that in the fossil. 
See Duncan’s figure 212. 
The dome-shaped cell bottoms shown in Duncan’s figure 
212 will also serve to refute the statement that “the bottoms 
of the cells of vespid nests are not dome-shaped, as in the 
fossil, but are flattened or angular.” It is true that around 
the margins of the combs of most nests the cell bottoms are 
flat or angular; but this is not true for all parts of the 
comb or for all conditions. The bottoms of most cells in 
long-abandoned nests are filled with irregular fecal pellets 
or other debris. In combs where remnants of the silk cocoons 
spun by the larvae still line the cell walls and cover the fecal 
pellets deposited by previous inhabitants the bottoms of the 
cells are perfectly dome-shaped as may be seen in a nest 
of the common hornet, Vespa (=Dolichovespula) maculata, 
now in my possession. 
The statement that the heights of the dome-shaped projec- 
tions on the fossil are “remarkably uniform” is an unwar- 
ranted exaggeration. The degree of irregularity in height 
is as great as any observed in the nests of living wasps. To 
the criticism that the cells of vespid nests taper, being wider 
at their openings than at their bases, whereas in the fossil 
the cells have a constant width, the reply is that the degree 
of tapering varies from nothing to very considerable propor- 
tions in different nests and different species. 
“In the fossil the substance between the cells is nearly as 
thick as half the diameter of the cells” (p. 53) . This meas- 
urement was evidently estimated by looking down upon the 
dome-shaped projections of the fossil and noting the yellow- 
ish clay lying between the bases of adjacent domes. This 
extraneous material, however, is no indication whatever of 
the thickness of the original vertical cell walls, but may be 
3 Duncan, Carl D. A contribution to the biology of North American 
vespine wasps. Stanford Univ. Pub., Biological Sciences, vol. 8, no. 1, 
1939. 
