A CHAPTER OF LIFE-HISTORIES. 75 
paralyzed but is not killed. The wasp then drags her 
prey into her hole, and deposits an egg on the motion- 
less but living insect, apparently knowing that death 
will not occur until her egg has become a larva and 
requires food. When the larva appears he finds his 
food still living, and makes it last until he is ready to 
assume the pupal condition. This is a remarkable 
insect adaptation for the preservation of food. 
There are many of these wasps. Some of them live 
in holes in the ground, which they stop up and conceal 
Fic. 67.—A Microgaster Fly (magnified). c, larva of a microgaster in 
the caterpillar of a cabbage-butterfly.. 
in very ingenious ways after the egg and its provender 
have been stored away. 
Others build their nests or cells of mud, enclosing 
the young and its food in earthen jars. 
A full-grown mud-wasp may be kept in confinement 
for a time and fed on sugar and water. Her mem- 
branous wings, four in number, are folded over her 
back when at rest, but during flight they are spread 
out and the fore and hind wings are fastened together 
in such a way by hooks and grooves that they appear 
like a single pair. 
