ENTOMOLOGIST AND BOTANIST. 



355 



ical rather than au entomological cause, tliat it 

 was principally due to drouth, bad culture and 

 poor soil, and that the Phylloxera was therefore 

 incidental; and acting upon this view, suggested 

 that water, with manure and good cultivation, 

 would do away with it ; while the latter main- 

 tained that the Phylloxera was the sole cause of 

 the trouble. There are, doubtless, certain condi- 

 tions of soil wliich will prove favorable to the 

 increase of the louse, and it may also be influ- 

 enced by the seasons and by good or poor culti- 

 vation ; but that this insect should be found only 

 on such roots as are already diseased is liighly 

 improbable, and there can be no reasonable 

 doubt that M. Lichtenstein is right in attrib- 

 uting the disease directly to the Phylloxera. 

 The appearance of mites is the almost inevita- 

 ble consequence of diseased and rotting vegeta- 

 tion, but Plant-lice cannot live on such vegeta- 

 tion, and invariably leave it as soon as they have 

 by their punctures reduced the healthy tissues 

 to such a state. Moreover, the history of our 

 own louse, which we shall now proceed to give, 

 corroborates M. Lichteustein's views. 



In Missouri tliis insect has proved very injuri- 

 ous to the Clinton vine for several years past^— at 

 least as far back as 1864 — and Mr. Geo. Hus- 

 maun informed us that last year it actually de- 

 foliated three-fourths of an acre of Clintons and 

 Taylors on bottom laud at Bluffton, though it 

 did not appear to do much injury on the hills. 

 The past season it has been very bad around 

 Ivirkwood, where we had an excellent opportu- 

 nity to carry on our observations. 



In this latitude the first galls are noticed by 

 about the middle of May, and by the middle of 

 June they begin to be quite common. It occurs 

 most abundantly on the Clinton and Taylor, but 

 we have found it on the wild Frost Grape ( V. 

 cordifolia), and such other cultivated varieties of 

 it as Golden Clinton and Huntington ; also on the 

 Delaware, and early in the year we even found 

 a few large galls on the Concord. According to 

 Dr. Morse it also occurs on the lona, which is a 

 variety of the Northern Fox Grape ( V. labrus- 

 ca). The galls vary somewhat in appearance, 

 according to the vine upon which they occur, 

 those we have noticed on the wild Frost Grape 

 being more hirsute than those on the cultivated 

 Clinton, and these again rougher than on the 

 Taylor. 



The few individuals wliicli start the race 

 early in the year station themselves upon 

 the upper side of the leaves, and by constant 

 suction and ii-ritation soon cause the leaf to 

 swell iiTegularly on the opposite side, while 

 the upper pai-t of the leaf gradually become? 



fuzzy and closes, so that the louse at last sinks 

 from view, and is snugly settled in her gall. 

 Here she commences depositing, her bulk in- 

 creasing during preguancy. Eventually she 

 grows to be very plump and swollen, acquires a 

 deep yellow or orange tint, and crowds the space 

 within the gall with her small yellow eggs, num- 

 bering from fifty to four or five hundred, accord- 

 ing to the size of the gall. The young lice are pale 

 yellow, and appear as at Figure 219, d, e. As 

 soon as they are hatched they escape from the gall 

 through the orifice on the upper surface of the 

 leaf, which was never entirely closed ; and, taking 

 up their abode on the young and tender leaves, in 

 their turn form galls. The mother louse, after 

 completing her deposit, dies, and the gall which 

 she occupied dries up. There are several genera- 

 tions during the year, and tliis process goes on 

 as long as the vines put forth fresh leaves. As 

 the galls multiply and the growth of the vine 

 becomes less vigorous, the young lice sometimes 

 so completely cover the upper surface of the 

 newly expanded leaves as not to leave room for 

 them all to form galls. In tliis event the leaf 

 soon perishes, and the lice perish with it. When 

 two or more lice are stationed closely together 

 they often form but one gall, which accounts for 

 the presence of the several females that are some- 

 times observed in a single gall. Those leaves 

 which have been badly attacked turn brown or 

 black, and sooner or later fall to the ground, so 

 that the vine may become entirely denuded. By 

 August the insects generally become so pro- 

 digiously multiplied that they often settle on 

 the tendrils, leaf stalks, and tender branches, 

 where they form excrescences and gall-Uke 

 growths, difiering only from those on the leaves 

 in such manner as one would naturally expect 

 from the ditference in the plant tissues. By this 

 time the many natural enemies of the lice begin 

 to play sad havoc vdth them ; and after the vine 

 has finished its growth the young lice, finding 

 no more succulent and suitable leaves, begin to 

 wander and to seek the roots, so that by the end 

 of September the galls are deserted, and those 

 few remaining on the vines generally become 

 mildewy, and finally turn brown and dry up. 

 Upon the roots the lice attach themselves singly, 

 or in little groups, and cause by their punctures 

 little swellings and knots, wliich eventually be- 

 come rotten. Where vines have been badly 

 afibcted with the gall it is difficult to find a per- 

 fectly healthy, fibrous root. Strange enough, 

 these lice not only change their residence as win- 

 ter approaches, from the leaf above ground to 

 the root below ground, just like the Moor, who, 

 having passed the summer on his roof, gets into 



