30 
the hours of darkness are often not particularly cool, wasps that 
do not hide in the ground may not really sleep a great deal. On 
moonlight nights i have heard the large Carpenter bees buzzing 
at Solanaceous flowers; the few wasps “that I have inspected dur- 
ing the night, no matter how cautiously approached, were always 
wide awake and alert... But where chilly benumbing nights pre- 
vail, wasps directly exposed to the atmosphere are quite dead to 
the world—until the sun arouses them. This 1s common in tem- 
perate regions. 
Bequaert (1918), p. 23, speaks of a wasp, Provespa, as being 
“adapted to nocturnal habits and restricted to the Oriental re- 
gion.” He also makes a note of two species of crepuscular bees 
taken in S. W. United States. 
ENEMIES. 
Both young and adult wasps have numerous enemies. Perhaps 
the most severe check to many species are ants. These obnoxious 
creatures, belonging to the genera Pheidole, Pheidolegiton, So- 
lenopsis and Monomorium, for example, often rob the wasp of 
her prey, occupy her nest, and even penetrate cocoons buried in 
the ground. It is very noticeable that while a few wasps actually 
provision their burrows with ants (Aphilanthops, Fertonius), 
they have in general a decided aversion and fear of them. Para- 
sitic wasps, beetles and flies are other serious enemies, and a cer- 
tain large tropical Vespa or hornet plunders many a nest of 
solitary and social wasps. Certain Aculeate wasps (Ceropales, 
Mutilla, some Stizini, etc.), prey upon the young grubs or their 
food. 
Economic STATUS. 
Taken as a whole wasps are beneficial insects and destroy an 
incalculable number of harmful insects, as well as some beneficial 
ones; among those addicted to the latter habit are species of 
Philanthus and Palarus which prey on the hive bee and others ; 
Mutillidae or “Velvet Ants” destroy the young of other w asps, 
as do the brilliant cuckoo wasps and a host of other kinds. Asa 
rule, people who are not afraid of spiders regard them as destroy- 
ers of obnoxious flies, millers, ete. Perhaps spiders, even up 
to the giants of their kind, have more wasp enemies than do 
insects. A whole family, the Psammocharidae or Pompilidae, 
bring up their young upon spiders. Many genera in other families 
prey upon them and the mud-daubers (Sceliphronini) literally stuff 
their cells with such provender. Thus one wasp may destroy up- 
