38o 



NOTES ON THE APHIDES OF THE CULTIVATED PEAS 

 (PISUM SATIVUM AND LATHYRUS LATIFOLIUS) 

 AND THE ALLIED SPECIES OF MACROSIPHUM. 



By Fred. V. Theobald, M.A., F.E.S.. Hon. F.R.H.S., etc. 



(Plates XIV and XV.) 



In certain years the pea crop, both field and garden, suffers 

 to a considerable extent from the attack of Aphis. This is 

 not only the case in Europe but also in America. In Britain 

 I have found three species feeding and breeding on peas, not 

 only on the edible varieties but also on sweet peas, everlasting 

 peas, and the Blue Pea. 



By far the most general and serious enemy is the Green 

 Pea Louse {Macrosiphum -pisi Kaltenbach). 



The other two are Megoura viciœ Kaltenbach and Aphis 

 rumicis Linnaeus. The latter has perhaps the widest range 

 of food plants of all the Aphididœ, but it seldom does much 

 damage to peas, and as I have treated it elsewhere nothing 

 will be said concerning it here.^ 



The Green Pea Aphis {M. pisi Kalt.) has several close alhes 

 feeding on different plants, two of which were described as dis- 

 tinct species, but which since have been sunk as synonyms. 

 I w'ish to show here that they are quite distinct species. This 

 narrows down the great difficulties of preventive treatment, 

 as if the Green Pea Louse bred on several very abundant wild 

 plants, which grow in almost every wood and hedgerow, the pos- 

 sibiHty of checking this pest w^ould be well-nigh insurmountable. 



Kaltenbach, in describing .4 /)A¿s pisi {Mono. Pflanz., 23, 11), 

 refers to Aphis ulmariœ Schrank {Faun. Boic, ii., m, 1221). 



Schrank' s name ulmayiœ has been adopted by Walker, 

 BucKTON, Schouteden, and others for the green Macrosiphum 

 on the Pea, Meadow Sweet, Wild Avens or Geum, and other plants. 



^ Journal Board of Agriculture, voL xix., No. 6, September 1912, 

 pp. 466-76. 



