386 LIFE STORIES OF AUSTRALIAN INSECTS. 



name ''American blight" or simply "blight" is often 

 applied to this form. This insect attacks the roots 

 and stems of apple-trees, causing irregular, gnarled 

 growths, which are often much larger than the 

 stems themselves. 



Vegetables such as cauliflower, turnip, radish, 

 and cabbage are frequently attacked by aphides. 

 The genus Phylloxera, which is such a serious pest 

 on grape vines, is an aphis with a complicated 

 life history. 



Enemies of Aphides. 



The lady-bird beetles {Coccinellidae) are one ot: 

 of the best enemies of this pest. Both larvae and 

 adults attack them, and are so voracious that, if 

 numerous, will rid the trees of them. 



The larvae of the lace-wing insect are a very 

 effective means of getting rid of aphides. The 

 long, trunk-like mouth can impale an aphis with 

 great ease, and the amusing habit of throwing the 

 skins on their backs is well worth watching. 



The larvae of certain species of hover fly are also 

 devourers of these destructive pests. 



The young (particularly) of the praying mantis 

 also feed on them. 



Small chalcid wasps parasitise aphides. 



We bred out a small black wasp from the dried 

 skin of an aphis which had been used by the wasp 

 as a cocoon, when the wasp maggot pupated. We 

 had noted a curious-looking swollen apliis of a fawn 

 colour, and placed several in a small box and awaited 

 results. Tiny black parasitic wasps emerged 

 (chalcids). 



