LG Bulletin of the Brooklyn Entomological Society. Vol. XIV 
Perhaps of all Hymenoptera, the Eumenidz, or solitary folded-winged 
wasps, show us the greatest! variety of nesting-habits within the limits of 
a genus. In the fifty odd pages of Chapter XIII, the Raus tell us the his- 
tory of ten species of Odynerus, Ancistrocerus and Monobia; all provision 
their cells with caterpillars, the almost invariable prey among solitary 
Vespide. But, while certain forms merely dig their burrows in the soil, 
often providing the entrance with an elegant, recurved turret, others 
build mud-partitions in galleries which they find in logs, and still others 
are regular mud-daubers, fixing their mud-cells on stones or plants. 
In the general considerations with which they conclude their book, the 
authors first call attention to the vast variety of types of psychic phe- 
nomena found within the taxonomic limits of Sphecide and Vespide. 
They declare their inability to explain the activities of wasps, either by the 
machine-theory of Bethe, who refuses to credit animals with any psychic 
qualities whatever, or by the tropism-theory of Loeb. Their interpreta- 
tion of wasp behavior is admirably summed up in the following quo- 
tation from Professor Wheeler’s brilliant introductory pages: “ Most of 
the activities can be readily interpreted as chain-reflexes or ‘instincts’ in 
the usual biological sense of the term. They are relatively fixed or stereo- 
typed and undoubtedly hereditary and therefore represent the most ancient 
and most solidified complex of the behavioristic cycle. But there stand 
out from this complex many activities which are less mechanized and of 
such a nature as to demonstrate that the wasps possess emotions and asso- 
ciative memory, that they exercise discrimination and choice, that they 
learn by experience and form habits in the restricted sense of the term 
and that they can modify their behavior adaptively in response to unusual 
stimuli on the basis of previous experience and therefore behave, to a 
limited extent, like intelligent beings.” 
Entomologists and other nature-lovers cannot but feel grateful to Mr. 
and Mrs. Rau for their admirable contribution. In making their wasp- 
studies they did not venture on lengthy and costly voyages to far away 
countries teeming with real or imaginary dangers. We follow them in 
their diligent observation of a Bembix-colony to a St. Louis baseball- 
field, where too often, alas, they are driven away by “a noisy American 
baseball crowd,” or we see them digging for the burrows of Xylocelia in 
the side of a gully in a vacant city lot, filled in with pieces of glass, crock- 
ery, cinders, etc.! There are many other features of their work which 
appeal to us and will make it a model and inspiration to others: the style 
of presentation which is clear and fluent, yet ornamented just enough to 
be attractive to the general reader; the care which has been taken to have 
each member of their little wasp family accurately named by an authority; 
but above all their unequaled skill and patience in following the wearisome 
trials and struggles, joys and pains of their highly nervous and often 
elusive favorites. Indeed with right do they quote the poet’s saying: 
“He also serves who only stands and waits.” 
J. BEQuUAERT. 
