78 
Proceedings of the Royal Society of Edinburgh. [Sess. 
VIII. — On the Life-History and Bionomics of Myzus ribis, Linn. 
(Red-Qurrant Aphis). By Maud D. Haviland, Bathurst Student 
of Newnham College. Communicated by Professor F. 0 . Bower, 
F.R.S. 
(MS. received November 14, 1918. Read January 20, 1919.) 
Synonymy. 
Aphis ribis, Linn., Fabr., Schrank, Kalt., 
Flogel. 
Myzus ribis , Pass. ? Buckton. 
Rhopalosiphum ribis , Koch. 
Aphis galeopsidis, Kalt., Walker. 
Phorodon galeopsidis , Pass., Buckton. 
Myzus ivhitei , Theobald ? 
Myzus dispar, Patch ? 
Introduction. 
Myzus ribis , Linn, (red-currant aphis), has attracted the attention of 
entomologists for more than a hundred and fifty years. But in spite of its 
abundance, wide geographical distribution, and economic importance as a 
pest of bush fruits, the complete life-cycle has never been determined. It 
was with the view of settling the disputed question of the fate of the aphis 
in the summer, and in the hope that elucidation of the bionomics of this 
species would throw further light on some uncertain points in the life- 
history of other migratory Aphidince — -notably on the production of the 
sexuales — that these researches were undertaken. 
I must express my sincere thanks to Professor J. Stanley Gardiner, who 
gave me facilities to carry out the work in the Zoological Laboratory, 
Cambridge, and to Miss Stephen, Principal of Newnham College, who per- 
mitted the use of her garden for the cultivation of the necessary material. 
Mr F. Balfour-Browne has helped me with much useful suggestion and 
criticism, and I would particularly express my thanks to Mr H. H. Brindley 
for his advice and assistance. I must also thank the Trustees of the 
Balfour Fund for a grant awarded to me for the prosecution of the work. 
The Nature of the Attack and its Remedy. 
Myzus ribis is commonly, though not invariably, associated with the 
presence of large red blisters on the leaves, but it is still an open question 
whether these are always caused by the aphides. The deformity and 
discoloration are generally apparent as soon as the buds open and before 
the leaves are fully unfolded. The red colour of these blisters is due to 
anthocyanin, a soluble pigment common in plants. It is possible that 
