The _Calicurgus_ will not actually enter a burrow when there is a spider in it, because if it did so the spider would speedily dispose of the aggressor by the aid of its poisonous fangs. The _Calicurgus_, therefore, has recourse to strategy with the object of getting the spider out of its nest; the wasp seizes its redoubtable foe by one foot and pulls; probably it fails to extract the spider, and in that case rapidly passes to another burrow to repeat its tactics; sooner or later a spider is in some moment of inattention or incapacity dragged from its stronghold, and, being then comparatively helpless, feels itself at a disadvantage and offers but a feeble resistance to the wasp, which now pounces on its body and immediately inflicts a sting between the fangs of the foe, and thus at once paralyses these dangerous weapons; thereafter it stings the body of the spider near to the junction of the abdomen and cephalothorax, and so produces complete inactivity. Having secured its prey, the wasp then seeks a suitable hole in which to deposit it; probably an empty burrow of a spider is selected for the purpose, and it may be at a height of several feet in a wall; the Hymenopteron, walking backwards, drags its heavy prey up the wall to bring it to the den. When this is accomplished an egg is deposited on the spider, and the wasp goes in search of a fragment or two of mortar, with which the mouth of the burrow is finally blocked. Fabre's accounts refer to the habits of several species, and give a good insight into some points of the instincts of both the spider and the wasp. It seems that a sense of superiority is produced in one or other of the foes, according as it feels itself in suitable conditions; so that though a spider out of its burrow and on the ground is speedily vanquished by the Pompilid, yet if the two be confined together in a vase, both are {103}shy and inclined to adopt defensive or even evasive tactics, the result probably being that the wasp will be killed by the spider during the night, that being the period in which the attacking powers of the spider are more usually brought into play.