THE VICTORIAN NATURALIST. 79 



Ichneumons. 



In searching for wood-boring insects we sometimes find the 

 larvre of various wood-boring beetles that have been killed 

 by the Ichneumons. The question may arise as to how an 

 Ichneumon could reach one of these larvae which are nearly 

 always buried in the wood, or between the bark and wood. It 

 is hardly possible that the Ichneumon laid its eggs on the larva 

 directly it emerged from the egg, as the number of Ichneumon 

 cocoons found inside some of the larvse is sometimes 15 or more. 

 I noticed a great many Ichneumons of the genus Pimpla on 

 " peppermint trees" that had been killed by " ringing." Some of 

 these insects had their ovipositors buried in the bark, and, 

 thinking that they might be depositing their eggs in some of the 

 wood-boring larvse, I held the fly, and then opened the bark with 

 a knife. In every instance there was a wood-boring larva directly 

 under the ovipositor, and in some the ovipositor had pierced the 

 skin. This may account for the way in which some of these 

 larvse are attacked. 



Anyone who takes an interest in the entomology of Victoria 

 will be well acquainted with the cocoon made by the larva of the 

 moth. Darotifera vulnerans. The first thing, perhaps, that strikes 

 the observer is the great number that have been killed by the 

 Ichneumon flies. 



Now this seems strange, as the larvse are protected by eight (?) 

 rays of fine bristles which the larva can raise on being alarmed, 

 and which are capable of inflicting a painful sting. The Ichneu- 

 mons seem to know this, and wait until the larva spins its 

 cocoon. 



On 15th January, 1887, I had the pleasure of seeing one of 

 these Ichneumons flying round, and occasionally settling on the 

 trunk of a tree. I thought at first sight it was a wood-boring 

 insect, but on closer inspection it turned out to be an 

 Ichneumon. It was searching for some larva or cocoon in 

 which to deposit its eggs. It soon found a cocoon of the 

 larva described above, and set to work in the following 

 manner : — Grasping the cocoon with her legs, and more 

 especially with the last pair, she brought her ovipositor to work 

 on the surface of the cocoon, the auger being placed so that it 

 liad all the pressure of the last pair of legs directly upon it. In 

 this position it worked for twenty minutes, when it bored through 

 the wall of the cocoon and deposited one egg on the larva, as I 

 found on inspection. 



C. C. Brittlebank, Spring Vale. 



