TWO POTTER WASPS 379 



excretion even when stored in the jugs, a process which par- 

 alysis from her sting would be likely to prevent. 



The span-worms are pushed into the jug entrance one 

 by one from the outside. Two or three of the victims are 

 always smaller than the rest. These are collected first and 

 stuffed in next to the elongated bow-shaped egg, which is 

 cemented by its posterior end to the wall of the base before 

 it is quite finished. The process of storing requires several 

 days and meanwhile the egg hatches and the young wasp, 

 a footless maggot of thirteen segments, commences to feast 

 upon the stores. These smaller caterpillars are doubtless 

 very tender and therefore easier for the larva to consume 

 during its first hours of weakness. The jug is not sealed 

 by the parent wasp until the grub is at least a day old. In 

 eating, the youngster consumes the entire caterpillar, scrap- 

 ing the interior of its victim's head as a delicacy and in its 

 final greed consuming even its hard covering of chitin. 



The egg hatches in forty-eight hours. At birth the grub 

 measures three millimeters in length. It grows very rapidly 

 reaching its full length of sixteen millimeters in five days. 

 In shape it somewhat resembles the abdomen of a large wasp 

 and is made up of thirteen segments. Its head consists of a 

 pale yellow bead, slightly cleft in the center and bearing two 

 heavy, red-brown mandibles protruding above the more 

 fleshy parts of the mouth. In appearance the grub reminds 

 one of a bull-dog with its protruding under jaw. For ten- 

 acity it surpasses even this king of the canine world, clinging 

 to its victim with a grip that continues for five whole days, 

 until there is nothing left to cling to ! 



When the feast is over, the larva lies quite motionless 

 for twenty-four hours, before preparing itself to await pu- 

 pation. These preparations are rather elaborate and require 

 an entire day. First a heavy coat of silvery mucous is ap- 

 plied to the interior of the jug. It is brushed over every bit 

 of the concave walls with minute care. Only the lower part 

 of the grub's mouth is brought into use, the mandibles re- 



