The crop is now and then completely ruined by this pest, and 

 the trees have a serious set-back for the next season and 

 probably for a longer time. 



The Green Apple Aphis (A. pomi) may on occasions 

 produce a' certain amount of leaf-curl, but never to the same 

 disastrous extent as A. malifolice. Moreover, it never occurs 

 in such vast numbers. It mainly feeds upon the young top 

 growths, and although producing but little deformed growth, 

 it nevertheless checks the health of the tree, especially when 

 on young stock. 



The Oat Apple Aphis (S. avence) does little harm as a rule, 

 except where it invades the blossom trusses, in which case 

 appreciable damage may be done. It produces little or no 

 leaf curling, appears earlier, matures and flies away much 

 sooner than the other two kinds. 



Description. The general appearance of the aphides 

 found on apple is familiar to most people, while the 

 blue-black or reddish colour of the Eosy Aphis usually 

 enables this species to be distinguished from either of the" 

 other two. Accurate distinctions, however, cannot be given 

 without entering into greater detail than the average reader 

 desires. The following descriptions, therefore, are printed 

 in small type and may be passed over except by those who 

 require some guide as to the identification of the species. 



(1) Apterous or Wingless Viviparous Females : 



1. A . malifolice. Blue-black, slatey-grey or pink. Cornicles 



long, black; fat, rounded and more or less mealy. 



2. A. pomi. Green, not mealy. Cornicles long and black. 



3. S. avence. Green, not mealy. Cornicles rather short, con- 



stricted at base and apex, brown and green. 



(2) Alate or Winged Viviparous Females: 



1. A. malifolice. Cornicles black, rather long. Abdomen red 



and black. 



2. A. pomi. Cornicles black, rather long. Abdomen green, 



with black lateral spots. 



3. S. avence. Cornicles pale brown to green, rather short, con- 



stricted at base and apex. Abdomen green, with black 

 lateral spots. 



Life-Histories. All three species pass the winter in the 

 egg stage on apples and pears. The small oval eggs are 

 pale at first, but soon become black and shining. They are 

 placed on the shoots and buds, those of the Rosy Aphis 

 and the Oat Aphis mostly singly, but those of the Green 

 Aphis in masses all over the wood. These eggs hatch during 

 April into wingless females, usually known as " Mother 

 Queens," which are viviparous (capable of giving rise to 

 living wingless females in every respect resembling them- 

 selves), their progeny quickly reaching enormous numbers. 

 These wingless females act somewhat differently in the 

 different species; those of the Eosy Aphis cause the leaves 



