128 LIFE STORIES OF AUSTRALL^N INSECTS. 



swarming ; they are often thought by farmers to 

 be "caterpillar eggs" and are destroyed by them 

 in consequence. These cocoons should never be 

 damaged, but preserved, for later on they will bring- 

 forth a crop of active little wasps, ready to kill 

 many injurious grubs. 



"There is another group of braconid wasps that 

 are almost confined to plant aphides. They punc- 

 ture the aphides and deposit the egg beneath the 

 skin. The little maggot feeding inside the aphis 

 soon empties out all the juice and then pupates. It 

 one examines the insects upon an aphis-infested 

 cabbage leaf, he will notice many aphides dry, dis- 

 coloured, and apparently lifeless, of dififerent colour 

 to the living ones, and swollen and shapeless. These 

 remain firmly attached to the surface of the leaf 

 by their claws, and later on, the imprisoned wasp 

 gnaws its way out through a hole in the side of thq 

 aphis skin, and comes forth a shining black wasp, 

 ready to start fresh parasites among the remaining 

 aphides. Nearly every species of plant aphis has | 

 some small Apanteles wasp parasite, that (late in 

 the season in particular) will kill a very large per- 

 centage of aphides. . Note that this large group 

 of parasitic wasps do not sting. They can pierce 

 the skin with their ovipositor in some cases, but 

 there is no poison ejected." 



