THE STATE ENTOMOLOGIST. 57 



The aimoiincenient that I have at hist ascertained one of the principal 

 causes — if not the sole cause — of this decline, and that, knowing the cause, 

 we may in a measure obviate it, will doubtless cause many a grape-grower 

 to wonder. Some may even pooh-pooh the idea, and deem it impossible 

 that they have so long remained in ignorance of so important a feet, that a 

 ^' bug-hunter" should discover it at last. Let the facts speak. * 



This destructive agent is none othei; than the little insect we are now 

 treating of. 



The general history of the louse, and the habits of the gall-inhabiting 

 type were sketched in mj- last Eeport, and need not be repeated. 



FURTHER PROOF OF THE IDENTITY OF THE AMERICAN INSECT WITH THE 



EUROPEAN. 



That the two are identical there can no longer be any shadow of a 

 doubt. I have critically examined the living lice in the fields of France, 

 and brought with me, from that country, both winged male and female 

 specimens, preserved in acetic acid. 1 find. that the insect has exactl}^ the 

 same habits here as there, and that winged specimens which 1 bred last fall 

 from the roots of our vines, accord perfectly with those brought over with 

 me. In the different forms the insects assume, in their work, and in every 

 other ininutia — the two agree. 



WHY I CONSIDER THE GALL-LOUSE AND ROOT-LOUSE IDENTICAL. 



Firstly, wherever this insect has been noticed in England, both the 

 gall-inhabiting and root-inhabiting types have been found. In France the 

 galls occur abundantly on such of our American varieties as are subject to 

 them here, while a few have occasionally been found on their own varieties. 

 Secondly, I have successfully transferred the leaf-lice on to the roots, while 

 M. V. Signoret has succeeded in obtaining leaf-galls from lice hatched on the 

 roots. Thirdly, the winged form obtained by Dr. Shimer from the galls in 

 this country' agrees in its characters with those from the roots. Fourthly, 

 the nodosities on the roots are, as already stated, perfectly analogous to 

 the galls on the leaves, and differ only in just such a manner as one would 

 expect from the diflei-ence in the plant tissues — a view greatly strengthened 

 by the feet that when the gall-lice are forced, by their excessive numbers, 

 to settle on the tendrils or leaf-stalks, they produce swellings and knots 

 approaching more nearly to those on the roots than to the galls. These 



* It is really amusing to witness how the facts here set forth have been receiveil bv tliose who 

 never spent ten minutes investigation of the subject in their lives. In the silkworm ilise;ise that has 

 of late years been so jtrevulent in Europe, M. Pasteur, after the most ))ainst:iking and ehiborate ex- 

 l)eriments, at wliich he sacrirtced his health, unraveled its mysteries, gave to the world the true pa- 

 thology of pebrine , and what is m)re, showed how it might be eradicated. Y'et, as I shall show tur- 

 ther on, the men most interested were very slow to believe the hard, dry facts which had been 

 snatched from the unknown, and — never having studied the case themselves— were more inclined to 

 consider the disease as som 'thing mysterious — something altogether beyond man's understanding, 

 and consequently uncontrollable. The m )St ignorant are always the m )st skeptical! I might men- 

 tion several parties who have exi)ressed their opinion th.it the Phi/lloxera has no connection with dis- 

 ease or ib-cline in the V^ine. To such, I sim;}lv sav : ex imine for vourselves, before giving an opinion. 

 Others whom 1 might m -ntiou go to the other"extreme and assert" that it must be the cau'se of mildew, 

 oidium, etc. , and without any good reason put a similar opinion in my mouth. To these last, 1 say : 

 Read aright, do not misconstrue, and by no means jump to conclusions! 



