i8 2 SOLITARY BEES AND WASPS. 



even into chrysalids and live caterpillars the cruel 

 fly will drive this tube, and leave her eggs where 

 they will hatch, and live until they are full grown, 

 feeding on the living substance. I have sometimes 

 kept caterpillars hoping they would turn into 

 beautiful butterflies, and instead of that I have 

 only had a crop of ichneumon-flies because their 

 eggs, unknown to me, had been previously laid in 

 the bodies of the unfortunate caterpillars. You 

 may ahvays know an ichneumon-fly by its quiver- 

 ing antennae ; they are never still for a moment 

 while daylight lasts, and the fly itself may also 

 be known by its long, slender body with a hair- 

 like waist. Some of the species are so minute 

 that they lay several of their eggs within a 

 butterfly's egg, and it affords quite enough food 

 for the ichneumon-grubs until they are full grown. 

 Others again are large insects with such a long 

 and powerful tube that they can pierce through 

 solid wood in order to reach the concealed grub in 

 which they desire to lay their eggs. I believe the 

 largest of the species measures four inches from 

 head to tail, the ovipositor being an inch and three- 

 quarters long. While I am speaking of parasites 



