DECEMBEJl MEETING. 239 



that they fall to ripen the fruit, and as a result \vc Ihid black-rot among tho 

 grapes. 



THE I'lIYLLOXERA YASTATKIX, I'LAX. 



So full was tho description given of tho grape lou.'-'e in tho lecture already re- 

 ferred to that I beg leave to refer you to that, and only Ijriclly recapitulate 

 here. 



The i'hylloxera is an American insect of (piite recent importation into 

 Europe. That it has been sucking the yitality from our vines during all the 

 past is beyond question. The insect is polymorphic, or exists in several forms, 

 each jieculiar form either the result of peculiar conditions, or else the laws 

 governing its development. In every form the lice arc exceedingly small, — 

 appearing to the unaided vision as mere specks, — whose vitality would hardly 

 be believed, except as they are seen to move. One form is smooth, oblong, and 

 yellow, and only works, — at least this is probable, — in galls on tho leaves. 

 These galls can not fail to attract attention, as they sorely mar the appearance 

 of the foliage. They are caused by the irritating presence of the lice. Within 

 the galls the young galls are brought forth and partially developed. These 

 gall-inhabiting and producing Pliylloxera are agamic, that is they reproduce 

 without males, — arc apterous, or possess no wings, and seem to do the vines 

 little harm. 



Another form — the root form — is not smooth, but covered with wart-like 

 projections, is oval, of a greenish yellow hue. These, too, like the others, are 

 agamic, and apterous. These, on the other hand, are by no means harmless. 

 They, by puncturing and sucking the juice from the r;)ots, cause them to 

 appear knotted, to die, the plant to decline, and when tho lice arc numerous, 

 to wither away. I have good reason to believe too, that in some cases at least, 

 if not in all, they are the cause, perhaps indirect, of the black-rot. 



In summer and autumn another form — the progeny of these agamic root- 

 lice — ajjpears with wings. These come forth and by flying to other vineyards 

 to deposit their eggs, spread this terrible evil with a rapidity not otherwise 

 possible. 



From the eggs of these winged lice, which eggs are of two sizes, come forth 

 the true males and females. After mating, the female louse, lays a single egg, 

 which may produce the leaf or root-form, as circumstances decide. 



Such in brief is the natural history of these insects as determined by Euro- 

 pean and American naturalists. Ilence we see that the presence of these pests 

 in our vineyards, need not Ijo a matter of conjecture only, for though the 

 insects are mere specks, and hardly to be discovered by the unpracticed eye, 

 this is not true of the galls on the leaves, or the knots on the roots, either of 

 which give quick indication of the dreaded foe. The knotted roots may not be 

 readily found on vines long and severely affected, as nearly all the fibrous roots, 

 those which feed both vines and lice, may be dead, but by examining several 

 vines, the quest Avill most surely be successful, if the foe is present, as the 

 knots arc very prominent, and upon the knots one soon learns to detect the 

 minute lice, as there are almost sure to be from one to several around each 

 knot. 



1)0 THE LICE CAUSE THE BLACK-ROT? 



While I may not aftirm positively that this is the case, I have reason to think 

 that it is. 



September 29th I visited the magnificent Delaware vineyard of Mr. AVilliams, 



