BURGLARS 285 



There are a number of parasitical insects of this 

 order known as Ichneumon Wasps, which deposit 

 their eggs in or on the caterpillars of butterflies and 

 moths. These we take no notice of at present, 

 because they are not burglars. Some, however, are 

 entitled to be so called, because the female with 

 her long egg-placer pierces the walls of a tough 

 cocoon and lays its egg in the contained chrysalis. 

 Some of these appear to be as gifted as Leucospis 

 in finding the exact location of their hidden victim. 

 Thus, Ratzeburg saw a species of Pimpla piercing 

 a leaf with its ovipositor. This looked at first 

 sight as though Pimpla had changed its habits and 

 was laying eggs in vegetable instead of animal 

 substances ; but on looking beneath the leaf 

 a cocoon of the Lackey Moth was seen to be attached 

 to the under side, and though Pimpla could not 

 see this she knew by some other sense just where 

 to strike. A similar sense is possessed by other 

 Ichneumon Wasps that bore through solid wood 

 in order to deposit their eggs in wood-boring 

 caterpillars. 



Under the head of Carpenters we have mentioned 

 (page 123) how the grub of the Horn-tail Wasp 

 (Sirex) feeds in the solid wood of pine-trees. Rhyssa 

 persuasoria is a large Ichneumon Wasp whose grub 

 lives at the expense of the Sirex grub, and to reach 

 the latter in its retreat the mother Rhyssa is pro- 

 vided with a delicate boring apparatus that is three 

 or four inches in length. 



There are two remarkable things to be pointed 



