The necessity of interpreting the actions of animals in terms of our own consciousness must be always with us. To interpret them at all we must consider what our own mental states would be under similar circumstances, our safeguard being to keep always before us the progressive weakening of the evidence as we apply it to animals whose structure is less and less like our own. We arrange the activities of the wasps that we have studied into two groups, Instincts, and Acts of Intelligence, it being understood that these classes pass by insensible stages into each other, and that acts that are purely instinctive when performed for the first time are probably in some degree modified by individual experience. In this classification the question of origin is not considered. The facts are grouped under the two heads, the inferences that they warrant being left for later consideration. Under the term Instinct we place all complex acts that are performed previous to experience and in a similar manner by all members of the same sex and race, leaving out as non–essential, at this time, the question of whether they are or are not accompanied by consciousness. Under Intelligence we place those conscious actions which are more or less modifiable by experience. It is this power that enables an insect to seek, accept, refuse, choose,—to decline to make use of this or to turn to account some other thing. Many writers prefer the term Adaptation for these activities, and it possesses certain advantages. With these definitions in mind, let us group the activities of wasps under the two heads. With the wasps of the genus Pelopæus we were present on several occasions when the young emerged from the pupa case and gnawed their way out of the mud cell. They were limp, and their wings had not perfectly hardened, and yet when we touched them they tried to attack us, thrusting out the sting and moving the abdomen about in various directions. These movements were well directed, and, so far as we could observe, quite as perfect as in the adult wasp. Stinging, then, is an instinctive act. The particular method of attack and capture practiced by each species in securing its prey is instinctive. Ammophila pricks a number of ganglia along the ventral face of the caterpillar; Pelopæus, we believe, stabs the spider in the cephalothorax, and probably the several species of Pompilus do the same. Astata bicolor adopts the same tactics in capturing her bugs, while it is said of the fly–catchers that they commonly overcome their victims without using the sting. It is by instinct, too, that these wasps take their proper food supply, one worms, another spiders, a third flies, moths, or beetles. So strong and deeply seated is the preference, that no fly robber ever takes spiders, nor will the ravisher of the spiders change to beetles or bugs. [Illustration: PARALYZED SPIDER HUNG UP ON SORREL BY QUINQUENOTATUS WHILE SHE DIGS HER NEST]