THE FOREST SHELL-WASP. 55 



the egg? If true to the rule, whidi is usual among solitary wasps, 

 it will become a hungry living grub in forty-eight hours, how then 

 shall I feed it? I have not given the parent wasp a chance to store 

 provisions for her larva, yet I am responsible for the orphan. 



The young of solitary wasps are fed on a variety of material, but 

 spiders and caterpillars seem to be most frequently chosen as prov- 

 ender. This I know from experience gained in the examination of 

 a great many nests. In the light of the present difficulty it may prove 

 a valuable bit of knowledge. The victims are stored within the cells 

 in a paralyzed condition from which they never awake. If they 

 were killed outright, they would soon putrefy in the cells, contam- 

 inate the budding wasps and turn the healthy nursery into a colony 

 of lepers. Therefore instinct, the great teacher of insects, guides the 

 wasp's sting only into the victim's nervous centers. The creature 

 so treated, passes into a comatose condition and lies powerless to 

 move or struggle while the young wasp sucks at its viscera. This, 

 then, is my grewsome course: I must catch, artificially paralyze and 

 present living food to the shell-wasp's grub if I am to rear the orphan 

 successfully. 



A search for caterpillars of the proper description is entirely 

 unsuccessful. They must be minute, soft, and without hair upon their 

 bodies or the youngster will die of indigestion. Moreover it is the 

 off season for them and unlike the wasp I cannot find them by the 

 sense of smell. Therefore as an experiment I substitute spiders for 

 the proper diet of span-w r orms. Spiders are abundant and easily 

 paralyzed. 



The nervous system of a spider is concentrated in a mass of gan- 

 glions gathered about the oesophagus. It lies in the cephalothorax, 

 or in that section of the creature which is foremost, there being but 

 two divisions. 



I secure my first victim from its web in the window corner. It 



