188 Trans. Acad. Sci. of St. Louis 
occupants which in turn would have reduced the number 
of bees and parasites. One nest gave forth its adults 
between June 26 and 29, 1917. 
The mud wasp, Sceliphron caementarium Drury. 
This mud-dauber stands in the same relation to the 
life of the unit as does the pipe-organ wasp, just men- 
tioned. These yellow-legged wasps, too, plastered their 
mud huts on the wooden porch overhead, and in one in- 
stance even attached one direct to the clay bank, in a 
depression which I had made in digging out a nest; a 
crooked, lop-sided, distorted piece of work it was, and 
it could not have been different in the cramped corner, 
but with yards of flat surface overhead, why should a 
sensible wasp choose a spot of this kind! 
Like the Trypoxylon politum, these wasps were occa- 
sionally seen entering the burrows in quest of spiders. 
Their discarded nests about this unit were utilized as 
homes by Trypozxylon clavatum, Ancistrocerus wnifas- 
ciatus, and Pseudagenia mellipes and the burglar wasp 
Chalybion caeruleum made the best of the opportunity 
to break into them in a most desperate way. 
The Larrid wasp, Tachysphex terminatus Smith. 
These little wasps appeared about July 16, 1917. They 
were digging their burrows in the loose dirt on the top 
of the clay bank and provisioning their nests with short- 
horned grasshopper nymphs. Toward the end of the 
month their numbers became much reduced; on July 30, 
only three females were in evidence. 
These wasps are supposed to be essentially sand- 
loving, but here we found them digging in the loose dirt 
