56 



red fly. A single winged female has settled there, and in 

 a day or so has produced many living young, which in 

 their turn are seen to be doing likewise. 



Three well-marked Aphides occur on the Roses in 

 this country, namely, Siphonophora rosarum, S. dirlioda 

 and S. rosce. 



The first-named lives, as far as we know, permanently 

 on the Rose. The second migrates to wheat, grasses 

 and polygonum, and the last to the teazel. 



This migration accounts for the often sudden 

 disappearance of the " fly " from Roses, and their equally 

 sudden re- appearance in September, and in the case of 

 S, rosce sometimes as late as October. 



Aphis Enemies. Fortunately the Aphides have 

 many natural enemies, which to some extent keep their 

 numbers down. 



The more important of these are shown on Plate 

 VIII., namely, the Lady Bird Beetles (Coccinellida), 



(Fig. 12), the Hover Flies (Syrphidce) (Fig. 10), the 

 Aphis Lion or Lace Wing Flies (Chrysopidcz) (Fig. n), 

 various Ichneumon and Chalcid Flies. 



The last-mentioned lay their eggs in the Aphides, 

 and the maggots feed on the Aphides internally. They, 

 as it were, hollow them out, and we find the dried skins 

 as pearl-like bodies sticking to the leaves and shoots. 



The Lace Wing Fly, who lays her eggs on curious 

 long stalks on the leaves, feeds upon the Aphis in the 

 larval stage, the larva being provided with large sickle- 

 shaped jaws for picking the Green Fly off the plants, and 

 to enable them to suck the juices from them. 



