80 [September, 



reflections given by the author on a subject -which he, perhaps, knows 

 better than any one. 



Yet, precisely, because it is a work destined to become a classic 

 compendium o£ Aphidology, I should like to prevent any misapprehen- 

 sion in a question on which I am not in perfect concordance of views 

 with Mr. Buckton : viz., the migrations of Aphides. 



Mr. Buckton says, page 72 : " Whilst fully sensible of the value 

 of much that M. Lichtenstein has written on the PempJiif/ince and 

 Phylloxerincs, I would guard myself from a committal to some of the 

 theories he has put forward, such as the periodic migration of Aphides 

 from one food-plant to another, and particularly as to his observations 

 that certain species feed on the leaves of the oak, and subsequently 

 descend to the roots of grasses for hibernation." 



Certainly there is an error, as I only spoke (and, precisely, in the 

 Ent. Mo. Mag.) of the gall-lice of the elm, not of the oak, and as the 

 late observations of Prof. Horvath, in Budapest, have put beyond 

 doubt the migration of the maize-root louse to the trunks of the 

 elms in October, I think if Mr. Buckton give a new edition of his 

 book, he will change the word " oak " into " elm," and put in a note 

 that since he wrote the above lines, migration of the elm-lice to maize- 

 roots has been observed. 



But, still more in the following page, 7-i, Mr. Buckton states 

 that Sign. Balbiani, the strongest opponent of the migration theory, has 

 observed the migration of the Siphonophora milJefoUi, as female, on 

 several grasses (?) and plants, as Cyperacece, Trifolium pratense, &c. ; 

 but here the migration seems to find an explanation, being in reference 

 to Aphides which live on annual plants. 



In Achillea miJIefolium an annual 'plsmt in Pai'is ? Here, and in 

 England, I believe, it is not so, and the roots of that plant last many 

 years ; so, if migration were not the rule, there were no more necessity 

 for the Siphonophora millefoJii to migrate to Trifolium, than for Te- 

 traneura uhni to migrate to maize-roots. More explanations are 

 desired, either from Mr. Buckton or from Sign. Balbiani. 



But to confirm or destroy the migration theory, how is it that 

 the clever observer of Weycombe, who, in his first volume, speaks of 

 Walker's idea as to the migration of the hop-blight {Phorodon 

 humuli) from the hop to the plum-tree, occupies three pages of his 

 4th volume, 186—188, to, "the extermination of the hop-Aphis/' 

 without saying if he has tried to follow the insect from the one plant 

 to the other, after having followed it from the leaves of the hop to 

 the roots on which he could not breed them ? 



