232 THE SOLITARY WASPS. 



pricks a number of ganglia along the ventral face of the cater- 

 pillar; PeJopaevs, we believe, stabs the spicier in the cephalo- 

 thorax, and probably the several species of Poinpilus do the 

 same. Astata hicolor adopts the same tactics in capturing her 

 bugs, while it is said of the fly-oatchers that they commonly 

 overcome their victims without using the sting. It is by in- 

 stinct, 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 caiTying their booty is a true instinct. Pom- 

 pihis takes hold of her spider anywhere, but always drags it 

 over the ground, walking backward; Oirj/helus clasps her fly 

 with the hind legs, while Bemhew 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 

 species. 



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

 the case of P. quinquenotatiis, or the reverse method pursued 

 by Astata, Ammophila, Bertibcx, and others of preparing the 

 nest before the food supply is secured is certainly instinctive; 

 as is also the way in which some of these wasps act after bring- 

 ing the prey to the nest. For example ;Sf. ichnennwuca places 

 her grasshopper just at the entrance to the excavation and then 

 enters to see that all is right before dragging it in. In exper- 

 imenting with a French Sphex which has the same habit, Fabre 

 moved the creature a little way off; the wasp came out, brought 

 it to the opening as before, and went within a second time. 

 This was repeated again and again until the patience of the nat- 

 uralist was exhausted, and the persistent wasp took her booty 

 in after her appropriate fashion. She must place the gi-ass- 

 hopper just so close to the doorway, she must then descend and 

 examine the nest, and after that must come out and drag it 

 down. Nothing less than the performance of these acts in a 

 certain order satisfies her impulse. There must be no disturb- 



