﻿94 SEVENTH ANNUAL REPORT 



form galls, but dwelt on the under side of the leaves like the Oak 

 species. This change of habit was brought about after the third gene- 

 ration ; and while it may probably never occur in nature, and finds 

 its parallel in the well known instances of rearing several generations 

 on a thick piece of root in tubes and bottles, yet it forcibh^ illustrates 

 the power of adaptation and change which the species possesses. It 

 may be also stated in this connection, that Dr. L. Kossler, of Kloster- 

 neuburg, Austria, has found the insect, of all sizes, above ground^ 

 under the loose bark near the base of the vine — a position which is 

 quite exceptional for it to assume. 



SPECIFIC IDENTITY OF THE GALL-INHABITING AND LEAF-INIIABITING TYPES,- 



The reader of these reports will scarcely need to be told that the 

 two types above mentioned are identical ; but as the fact has been 

 called in question by a few of our prominent grape-growers, I repeat 

 here what I wrote on the subject not long since for the New York 

 Tribune : 



In the October number of the monthly report from the Depart- 

 ment of Agriculture at Washington, there is the record of an experi- 

 ment by Townend Glover, Entomologist to the Department, the object 

 of which is, in Mr. Glover's language, " to prove the identity of the 

 Pemphygus [Pemphigus] vitifoliee or leafgall-louse, of Fitch, with the 

 Phylloxera vastatrix, or root-gall louse,* so injurious at present to the 

 vineyards in France, and in parts of this country also." This is the 

 experiment referred to in the Tribune of the first week of March last, 

 and the item detailing it, shows, as I had anticipated, that no galls 

 were produced. It also shows that " we cannot give the names of the 

 vines [experimented with] as accidentally the labels were thrown 

 away by the laborer when he removed the dead vines," and, though 

 closing with a confession that the experiment decides little or nothing, 

 it nevertheless appears to strengthen the belief held by many, that 

 the leaf louse and root-louse are not specifically identical. 



The item has been very generally copied in our agricultural 

 papers, and has been widely disseminated over the country, through 

 the monthly report, in which it first appeared. The average editor 

 and the average reader of our agricultural and horticijltural journals 

 have not, nor can they be expected to have, nor do they pretend to 

 have, profound knowledge in every specialty ; and for these reasons 

 items of this kind, coming from the fountain head, have a great in- 



♦This term, which is origiual with Mr. Glover, should be discouatenauced, as the term " gall,' ' 

 strictly eijcaking, applies only to abnormal vegetable growths, caused by insects dwelling within them j, 

 and not to mere swellings induced by insects which always live exposed. 



