66 INSECT BEHAVIOR 



first few hours of its life its mandibles are of a very rudimentary 

 character, in fact scarcely distinguishable until the grub is a day or 

 more old and are developed gradually to be in readiness later when 

 substantial parts of the spider must be eaten. The fact that at birth 

 the grub possesses no adequate appendages for chewing suggests an 

 interesting question: How does the tender creature make the first 

 incision through the mature wall of the spider's abdomen? Perhaps 

 the parent wasp pricks it and uses the minute drop of fluid that oozes 

 from the wound as mucilage with which to secure the position of her 



egg- 



The grub feeds for six days during this time it goes about its 

 meal in a thorough manner so that in the end not a hair of the stored 

 spider remains. Further the larva has changed greatly in size. At 

 birth it measures four millimeters, now it is seventeen millimeters 

 long and ready to spin its cocoon. 



Spinning is a laborious process requiring three whole days. A 

 slight network of silk is first thrown about the cell, within which 

 an inner cocoon of a far more substantial character is then con- 

 structed. It is somewhat longer than the grub, torpedo-shaped and 

 reddish brown in color, which is due to the varnish, so commonly 

 employed by the larvae of Hymenoptera, showing through from the 

 inside. 



The cocoon is in no way remarkable, in fact it is quite simple. I 

 have seen other larvae build more elaborate ones in a day, yet the 

 dauber requires seventy odd hours for so simple an operation. Its 

 nature is sluggish from the outset, and throughout its immature life 

 it is slow about its affairs. The egg requires three days to hatch, the 

 grub feeds six days, therefore it logically follows that spinning should 

 be a leisurely process. Consequently, the grub takes its time and 

 is none the worse for it. 



Seven days after spinning, pupation takes place. The creature now 



