226 Trans. Acad. Sci. of St. Louis 
Cuckoo-bees and parasitic wasps. 
These beautiful green bees, parasitic upon many 
forms of Hymenoptera, appeared about the bank dur- 
ing every season of the term of observation. They were 
directly parasitic upon many of the inhabitants, and 
were frequently observed following a returning mother 
to her nest, and were often seen prowling about and 
entering the nests of others. 
Only one species was found, Chrysis (Tetrachrysis) 
coeruleus Fab. [S. A. Rohwer]. These cuckoo-bees ap- 
peared with the first life on June 25, 1917, and were 
in almost constant attendance at the bank in summer 
from that date until near the middle of October. They 
appeared in great abundance in early summer, flying 
before the bank in the sunshine, searching over the sur- 
face and entering numerous crevices and bees’ tunnels, 
evidently taxing the legitimate life in the bank as much 
as did the Chalcids. Their numbers seemed to increase 
as summer advanced; but numerical estimates of this 
population are difficult to make at the early season. One 
may count the turrets of the bees, the pits of the ant- 
lions, or the webs of the spiders, but these transients 
sneaking about the dwellings of others, could not be 
definitely enumerated. 
The next year by August 10 their number seemed 
much reduced; on August 14 only one specimen Was 
seen, and none thereafter, excepting dead ones at the 
foot of the bank. One carcass of this bee was removed 
from the web of a spider. This was probably the 
natural time for the death of these bees, and we thought 
that a new generation would appear soon after. It was 
interesting to discover that with the disappearance of 
