SOLITARY BEES AND WASPS. 181 



cells and laying their own eggs with those of the 

 wasp or bee, which are of course destroyed by 

 the grub of this cruel intruder. 



A French naturalist writes that he saw a Ruby- 

 tail fly go into a Solitary bee's nest in a hole in 

 a wall, and when the bee came back she found the 

 Ruby-tail, and had a desperate fight with her. 

 The fly is able to roll up into a ball as a hedge- 

 hog does, but this did not save her, for the bee 

 sawed off her wings, and, dragging her out of the 

 nest, threw her on the ground, and went off to get 

 some more pollen. Poor Ruby-tail was not going 

 to be beaten ; she climbed slowly up the wall into 

 the bee's hole, and there she succeeded in laying 

 her eggs before the rightful owner returned, so 

 after all the bee's family were not saved by the 

 mother's brave defence of her nest. 



The Cuckoo fly is another species that victimises 

 bees and wasps in the same way, and the large 

 tribe of ichneumon-flies are always on the watch 

 to lay their eggs in any living things that will suit 

 their purpose. They possess a long, flexible tube 

 called an ovipositor, and by means of this they can 

 insert their eggs inside wasp and bees' eggs, and 



