Reflexes, Instincts, and Intelligence 651 



The Peckhams arrange the activities of the wasps they 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 the category instinct 

 they 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 they place those "con- 

 scious actions which are more or less modified by experience." With these 

 definitions in mind they group the activities of solitary wasps under the 

 two heads as follows : 



"Instinct. — With the Pelopasus wasps we were present on several occa- 

 sions 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 w-e could ob.scrve, quite as 

 perfect as in the adult wasp. Stinging, then, is an in.stinctive 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; PelopKus, 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 vic- 

 tims without using the sting. It is by instinct, too, that these wasps take 

 their proper food-supply, one worms, another spiders, a third flies 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. 



"The mode of carn,-ing their booty is a true instinct. Pompilus takes 

 hold of her spider anywhere, but always drags it over the ground, walking 

 backward; Oxj'belus clasps her fly with the hind legs, while Bembex uses 

 the second pair to hold hers tightly against the under side of her thorax. 

 Each works after her own fashion and in a way that is uniform for each spe- 

 cies. 



"The capturing of the victim before the hole is made, as in the case of 

 P. quinqiienotaliis, or the reverse method pursued by Astata, -Ammophila, 

 Bembex, and others of preparing the nest before the food-supplv is secured 

 is certainly instinctive; as is also the way in which some of these wasps act 

 after bringing the prey to the nest. For example 5. ichneumonea places her 

 grasshopper just at the entrance to the excavation and then enters to see 

 that all is right before dragging it in. In experimenting with a French 



