Field Studies of the Non-Social Wasps 351 
be the utility of stinging so as to paralyze the legs, in 
a species which has the habit of cutting off the legs of 
its prey? An egg, now discolored, was sealed to the 
left lateroventral surface of the abdomen. Cell ‘‘B”’ 
was likewise smooth on the inside; all of its roughness 
faced into the empty cell ‘‘C’’ where it would do no 
harm since it was empty. In ‘‘B”’ one spider, a young 
Philodromus sp. [J. H. Emerton] was found. This was 
dead, bore a dried, shriveled egg upon its dorsum, and 
had only three legs. The five that had been removed 
were the first, third and fourth on the left side and the 
third and fourth on the right. All these seemed to 
have been cut at the joint between the coxa and the 
femur, leaving clean-cut stumps. ‘‘D’’ was a very large 
cell between the last brood cell and the plug, and con- 
tained sufficient space for at least three P. mellipes cells, 
but without taking advantage of this space she had pro- 
ceeded to plug up the orifice. We ought to pause here 
to ask how the habit was acquired of sealing up the open- 
ing of the tunnel or old cell when her own cells within were 
sufficiently sealed, since in many situations of her nest, 
as under bark of trees, ete., she cannot seal up the cavity 
°r Space containing her cells. 
Fig. 39 again shows the great versatility of this little 
creature. In this case she did not actually build the 
usual thimble-shaped cells, but modified her work to 
resemble that of Trypoxylon clavatwm (fig. 54), and 
actually built walls to separate the larve instead of 
following the more elaborate plan of building separate 
cups for each. In contrast with the precaution of leay- 
ing an air space, as seen at ‘‘D”’ in fig. 39, and sealing 
the opening, we see (fig. 38) where the old mud-dauber’s 
cells were completely filled with thimble-like cells of P. 
mellipes and in other cases some of them were partly 
