﻿OP THE STATE ENTOMOLOGIST. 95- 



fluence in shaping popular opinion. It is all the more necessary, 

 therefore, that information coming from such a source be trustworthy. 

 The ostensible object of the experiment described, was to prove 

 the identity of the Phylloxera which forms galls on the leaves of the 

 Grape-vine, with that which causes the swelling and rotting of the- 

 roots of the same plant. The inference from the attempt is, that the- 

 two forms had not so far been proved specifically identical. Yet the 

 question had long since been settled by eminent observers, whose care 

 and thoroughness have won for them respect and authority. Already 

 inl86S, that eminent entomologist, J. O. Westwood, of England, who- 

 examined both types, announced that he could not perceive in them 

 specific difi'erence, and in the Fall of 1870, the specific identity of the 

 two types was proved by myself, by obtaining root-lice {radicicola} 

 direct from gall-lice {gallicola\ and by showing that the young of the 

 latter as they are carried to the ground by the fall of the leaf, creep 

 on to the roots to hibernate, and there assume the characters of the 

 root-inhabiting type. But anterior to my own experiments, the specific 

 identity of the two types was thoroughly proved by three different and 

 independent observers in France, and their observations are on record 

 in different numbers of the Messager du Midi. Since then the identity 

 of the two types has been confirmed in the most conclusive and em- 

 phatic manner by several observers, Maxime Cornu, more especially, 

 having recorded in detail, in the 6'ow?jo«;esi?ewfZwsof the Paris Academy 

 of Science, his thorough and painstaking experiments, in which he nob 

 only institutes the most careful and anatomical comparisons, but 

 records having actually watched the process of change from the one 

 to the other. These articles, though originally appearing in the 

 Gomptes Rendus^ have been copied in more popular works, while the 

 facts have been recorded in this country. Finally, the specific inter- 

 relation of the two types was still more firmly established last Winter 

 by the production of an abortive gall from a root-louse.* 



Indeed, the question has for some time been considered definitely 

 settled by all who are well informed on the subject. Yet while further 

 proof of the identity of the two types was scarcely necessary, all en- 

 deavors by experiment to obtain gall-lice from root-lice are praise- 

 worthy and interesting, if they are carefully made. But the value of 

 experiments like those made at Washington, where no intelligent 

 choice is made of the particular varieties of vine employed, and where 

 not even the names of the varieties are known, will appear from the 

 following facts, which are well understood by all who have kept au 



♦See Sixth Mo. Rep., p. 41. 



