THE INSECT WORLD 401 



usually have a velvety appearance, or look as if they were cov- 

 ered with a whitish bloom, and the wings are also either black or 

 yellow, like the prevailing colors of the body. They lay their 

 eggs in spiders, which they bury, and in which the larvae de- 

 velop. Perhaps this is a good place to mention the fact that 

 these digger-wasps make use of their stings and the poison se- 



FiG. 455- 



Pepsis formosus, tarantula-hawk. 



creted by them for preserving from decay and in a condition 

 suitable as food for their young the larvae, spiders, and other 

 insects upon which they feed. They sting their prey very care- 

 fully, in such a way as to paralyze and render it motionless, 

 while yet it does not die ; and the larvae, when they hatch, begin 

 feeding very carefully, so as not to kill their host until they them- 

 selves are sufficiently developed. The poison introduced seems 

 . to simply suspend life, or rather allows it to go on without a 

 waste of tissue. Spiders of all kinds are attacked, and even the 

 fierce tarantula of the South and Southwest has its enemy in an 

 enormous species oi Pepsis known as the "tarantula-hawk." 



Perhaps the most common forms belonging to this series are 

 those in which the abdomen ends in a small bulb-like structure 



26 



