PHYLLOXERID/K. 73 



retaining the term. The reader is referred to the 

 above paper in the ' Comptes rendus,' p. 1171, for 

 various details connected with the habits of this and 

 other species observed by M. J. Lichtenstein. 



"With reference to the word pupifera as employed 

 byM. Lichtenstein, Dr. Balbiani makes remarks to me, 

 which accord with my own opinion on the matter. 



He says : " Si Ton doit appeler des ceufs de corps 

 qui sont constitues essentiellement comme les ceufs 

 des autres insectes, qui se segmentent, et dans les- 

 quelles, les parties de Pembryon se forment successive- 

 ment et peu a peu ; ces corps sont des ceuf et non des 

 pupes comme je l'ai toujours soutenu." 



I may mention also the coinciding opinion of Prof. 

 C. Riley on this subject, who speaks of the u insufficient 

 and misleading nature of the theory regarding the 

 evolution of the Aphididae ; whilst calling the winged 

 females larvce and their eggs pupce" &c. 



Vide ' American Naturalist,' xvi, May, 1882, p. 409. 



I have obtained M. Balbiani's kind permission to 

 translate and publish a portion of a letter addressed 

 to me, which is of considerable interest ; since it con- 

 verts into a clear proof that which previously had 

 only been a conjecture. The discovery here noted 

 accounts for the total disappearance, for many months 

 above ground, of such Aphides as feed exclusively on 

 the leaves of annual plants. As M. Balbiani's obser- 

 vations have not been published they will be the more 

 acceptable. In an economical point of view they will 

 have interest to the hop-grower, since they will direct 

 attention to the probable winter nidus of the egg of 

 the Aphis which so often suddenly ruins his expecta- 

 tions of a fine crop of blossoms : expectations which 

 he had a right to calculate upon from the previous 

 healthy condition of the vines. 



This letter also has some bearing on the mooted 

 question of migration, and I quite agree with the 

 writer that there seems to be no necessity for any theory 

 of migration from one plant to another of a different 



