42 DESTRUCTIVE INSECTS OF VICTORIA : 



GH^gs are deposited that carry the insect through critical 

 periods, is still a mystery. Wherever and in whatever 

 manner the insect passes through winter, in spring it soon 

 reappears upon the plants, where it develops quite rapidly 

 by many generations, and spreads over the fields, the 

 winged individuals establishing new colonies in distant 

 localities. In America there are several parasitic enemies 

 of the Corn Aphis, especially amongst the small Hymen- 

 opfera^ and these creatures, two of the best of which 

 being Ceraphron triticum and Sijrphus torvus, the latter 

 genus being seen in Victoria hovering about flowers, 

 and often mistaken for bees. Professor Smith says it 

 hovers about the wheat in the bright sunshine, and the 

 female lays its long, oval, pure-white egg wherever she 

 spies a colony of Aphids large enough to support the 

 young larvae when hatched. In Victoria the above para- 

 sites are not known to exist, but we have others, as the 

 so-called ^' lace-wings," which are described in a former 

 number of this book, also many minute Hymenoptera^ 

 both of which, no doubt, assist in keeping down the 

 increase of this tiny pest. 



Prevention and Remedies. 



To practical farmers, the difficulties in the way of 

 dealing with this pest where on large areas will be at 

 once apparent, still something must be done, as a good 

 crop where attacked by Aphids will soon be ruined, or 

 next door to it, and it is no uncommon thing to find the 

 crop badly infested, and all within a very short period, 

 often in a few hoiu'S. (In a previous number of the book 

 the cause of the extraordinary increases of the AphidaB 

 has been fully explained, so that it need not be repeated 

 here.) As a preventive the use of certain artificial 

 manures such as sulphate of iron, nitrate of soda, kainit, 

 lime, &c., would appear to have a good effect. An analysis 

 of the soil to be treated should be made, especially in the 

 case of lime, so as to ascertain in what respect the soil is 



