THE SPHECID'S DUTY 93 



into the air with the cicada, which is now quiet and helpless. At first 

 she tumbles like a wounded aeroplane, but at length recovers, rights 

 herself and thus gains sufficient momentum to fly without halt to 

 the nest. 



The nest consists of a sloping burrow, continuing under the ground 

 for about eight inches in a straight line. A sharp turn is usually made 

 at this point and the tunnel carried on for twelve inches more. At 

 the extreme end there is an elongated cell, large enough to hold a 

 single cicada. Branches from the main passage are often excavated, 

 and occasionally one of the cells at the ends of these branches will 

 contain two cicadas. It has been stated that these cells containing 

 two victims bring forth much larger wasps than those containing one, 

 and as the female wasp is much larger than the male, it was thought 

 by a well-known entomologist that the cells containing the greater 

 amount of provisions produced the females and those containing a 

 lesser amount, the males. However, it does not seem probable that 

 an insect possesses the power of distinguishing her eggs to the extent 

 of telling which are to bring forth the males and which the females. 



When a cell contains its store of cicada meat, a single whitish egg 

 is laid under the middle leg of the victim. After this the burrow is 

 closed up by the wasp and her duties are finished. The eggs hatch 

 in two days, and the larvae, as the young grub-like sphecids are called, 

 start at once to suck the nourishment from the bodies of the cicadas, 

 later entering the hosts' bodies, where they attain full size in seven 

 or eight days. 



Now a rough cocoon is spun by each inside of its respective cicada, 

 wherein it later transforms to a pupa, the stage corresponding to the 

 chrysalis of a butterfly. 



In this soft, helpless condition it remains all through the winter, 

 until the following summer. Then, when the cicadas are calling 

 once more, the long buried cocoon, from which the hollow shell of 



