Wasps, Bees, and Ants 495 
Exceptions are those species which live as guests of other wasps, or as para¬ 
sites on other insects. 
The habit common to almost all of the solitary wasps of so stinging the 
prey, caterpillars, spiders, beetles, flies, bugs, or whatever other insects 
are used to provision the nests, as not to kill but only to paralyze it, is perhaps 
the most amazing part of all the interesting behavior of all these wasps. 
The advantage is obvious: killed, the prey would quickly decompose, and 
the hatching carnivorous wasp larva would have only a mass of, to it, inedible, 
decaying flesh instead of the fresh live animal substance it demands. But 
if stored unhurt, the prey would, if a cricket or spider or similarly active 
animal, quickly escape from the burrow, or if a caterpillar or weak bug, at 
least succeed, albeit unwittingly, in crushing the tender wasp egg by wrig¬ 
gling about in the underground prison-cell. More than that, unhurt, some 
insects could not live without food the many days that are necessary for 
the development of the wasp larva, especially in the face of the frantic and 
exhausting efforts they would be impelled to in their attempts to escape. 
But paralyzed, there is no exertion, metabolism is slight, and life without 
food is capable of being prolonged many days. The paralysis is due to 
the stinging by the wasp of one or more of the ganglia (nerve-centers) 
Fig. 698 .—Cerceris tuberculata, dragging weevil (Cleonus sp.) to nest. 
(After Fabre; natural size.) 
of the ventral nerve-cord. With a wasp species (Sphex jlavipennis) observed 
by Fabre,* which provisions its nest with crickets, each cricket was stung 
* Fabre, J. H., Insect Life, 1901. 
