240 Trans. Acad. Sct. of St. Louis 
lation works out so beautifully that I shall want to place 
this material experimentally at a temperature of 73° 
in November or February, to see if then the develop- 
ment and maturity occurs likewise. Had the 1917 pop- 
ulation (which emerged in abundance about June 25th) 
emerged on May 28, as did the 1918 lot, it would have 
spent the 15 days before its emergence at a temperature 
of 66 2/15°. 
This temperature phenomenon seemed to hold in gen- 
eral for most of the spring Hymenoptera, and I found 
them all appearing at one time, after the manner of 
Anthophora abrupta for example. The bank yielded 
its contents of this species all at one time each year, 
within a space of two or at most three days. Simulta- 
neously appeared also their Chalcid parasites, Mono- 
dontomerus. The green cuckoo-bees burst forth at their 
appointed time, and so too the caterpillar wasp, Ancis- 
trocerus fulvipes; the Monobia mud wasp, the Trypoxy- 
lon, ete., ete. The only exception was the carpenter- 
bee, Xylocopa virginica which appeared some time 
earlier.* 
This species is a wood dweller—not a cave dweller— 
and would, therefore, be influenced by temperature 
somewhat differently from those which live in the com- 
pact earth. Not alone in 1917 did I see this simultane- 
ous emergence of the various species and of all individ- 
uals of each of these species, but in 1918 and 1920 as 
well. It was as though some one touched an electric 
button and that button was labeled 73° F. 
The white-banded bees E. taurea and the dipterous 
parasites, demanding a higher temperature and hence 
*We do not know how this bee hibernates, but observations 
given elsewhere indicate a period of hibernation in the adult stage. 
