THE SPHEGIDE. 220 
with its mandibles, and carries them off in order to construct its 
nest. 
It begins by forming one chamber, which is hollowed out in 
the clay brought from a distance and stuck on to a wall, and 
as soon as it is finished the female goes a hunting, and, curiously 
enough, selects the most dangerous, bold, and well-armed creatures 
there are for its prey. It does not hesitate to attack spiders, 
in fact, it rather enjoys the fight with them. Doubtless, the strong 
sting of Pelopeus is a terrible weapon, and if it touches the spider 
there is an end of the combat, but if not, this last insect has its 
web at hand, threads of which it can throw with great rapidity 
and exactness. 
The Pelopeus is both bold and prudent, and approaches the 
web flying carefully, and usually it manoeuvres so well that the 
spider is stung before it can do anything; but it sometimes does 
happen that the spider is prepared for the attack, and the 
Pelopeus finds its movements paralysed by some fine threads 
being thrown over it. Then the spider encircles its enemy with 
layers of web, and devours it. 
But it does not often happen that the Pe/opeus is captured, 
on the contrary, it usually manages to bring one, two, or three 
spiders to its nest, according to their size. They are introduced, 
and an egg is deposited close to them, and then more clay is 
brought, and all is closed. Thus the first chamber is constructed 
and victualled, and then the female builds a second one on the 
side of the first and upon the same horizontal line, and fills it in 
the same manner, then the third and the fourth cells are added, 
and sometimes there are six or eight of them. The external 
surface of the nest is marked with long depressions, which cor- 
respond with the intervals between the cells. The lower part of 
the nest is thinner than the rest, and when the larve have 
become full grown and have undergone their metamorphoses the 
adult insects come out from this part and leave open holes. 
If a nest be detached from a wall before the second meta- 
morphosis has commenced—and this is by no means an easy 
operation, for the masonry of the Hymenoptera is good—the 
cells will be noticed to be occupied either by larvae or by cocoons, 
which have been made by them after the attainment of their 
