Twice afterward, in opening these nests, we found the same ants in possession before us. It is probable that they are a formidable enemy to this and other species of Pompilus; but they seem to find the spider by burrowing beneath the surface, so that the elaborate hiding of the nest from above cannot be meant as a protection from them. [Illustration: EXAMPLE OF EPEIRA STRIX THAT HAS BEEN PARALYZED AND HUNG UP ON BEAN PLANT BY POMPILUS QUINQUENOTATUS, THAT IT MAY BE OUT OF THE WAY OF ANTS WHILE SHE DIGS HER NEST] Pompilus quinquenotatus has a decided preference as to the spider that she takes. While Pelopæus and Trypoxylon are entirely indifferent both as to size and species, and the more nearly related Pompilus marginatus takes Thomisus, Drassus, Attus, Agalena or Lycosa, this more fastidious wasp will not be tempted from the spider of her choice. In more than fifty examples the victim in the play was invariably Epeira strix. If she must confine herself to one species she has made a fortunate selection, since there is no other spider so common in our neighborhood, not only in the woods, but around the barns and outbuildings. Most frequently it was the female that was taken, but this does not imply a preference for that sex, since the females are more abundant than the males. We have never seen the spider captured and do not know where the sting is given, but certainly this wasp wounds her prey very severely. The spiders that we took from her were either dead, or so completely paralyzed that it required great care and the use of a magnifying glass to determine that they were alive. The next stage of her proceedings we are familiar with, as we have frequently seen the wasp carry the spider. Unlike her sister, marginatus, she usually flies with it, and seems not at all encumbered by its weight. In many cases, however, she drags it, holding it by one leg and running rapidly backward. A suitable place for the nest being found, the spider is very prettily taken care of while the work is in progress. A plant, usually a bean or a sorrel, is chosen, and the strix is hung in the crotch of a branching stem, where it will be safe from the depredations of ants. This precaution is not always taken. We have many times seen the spider left on the ground, although there were plenty of plants at hand.