Aug. 



5.] 



♦ KNOWLEDGE ♦ 



175 



a long pause, during wliicli the performer changed her 

 shape several times. In the A condition, the curves of 

 her body were approximately circular, and regular from 

 side to side. At one time a flat margin was seen all 

 round, and a bump in the middle. B shows this form 

 in section, and it is something like the figure given by 

 Mr. Buckton in his valuable work. Fig. C represents 

 the appearance of a quiescent female surrounded by more 

 than fifty eggs. A finally got back into this lumpish 

 shape. 



In a day or two the egg-layers becmnc sc;iii-r, :iii(l tlicu 

 vanished altogether, but scores of lui-v;r inul piqn' i-ou- 

 tinued their depredations on the hedgo. Al;iiiy nak kaves 

 were spotted all over with orange-red implead ul' the fresh 

 greeny yellow fir.st noticed. These exhibited no egg- 

 layers, and the change of tint was the result of more com- 

 plete destruction of the chlorophyl and cell tissue. A 

 winged form was common on these leaves. 



The writer has oak in various hedges made on the 

 Sussex plan, but only one hedge was conspicuously 

 attacked by the Phylloxera, and the large oaks, so far as 

 could be seen, were not affected. The eggs, when first 

 laid, were smooth and glossy, but after a little while they 

 become pitted. None hatched while under several hours' 

 observation, and when, a few days later, more sjiecimeus 

 were wanted, none could be found. Buckton givrs the 

 size of the Queen Mother as 0-030 x 0-012, and 'describes 

 her as very small and flask-shaped, whicli eon-csponds 

 with A turned iipsido down. This form, howi vi r, was 

 only exhibited in my specimens when the cn-ij-layiim 

 was in process. 



The antenntB are three- jointed. Fig. I) shows two 

 joints, the terminal one having a curious oval dejiri'ssion 

 near the top, bounded by a raised wall. This does not 

 exactly correspond with the description in Mr. Buckton's 

 book, which, in describing the genus Phylloxera, says : 

 " Antenna; throe-jointed . . . The third joint much the 

 longest, roughly imbricated, with a circular tubercle 

 near its base, and a longer, somewhat inconspicuous, 

 tubercle, towards its apex." The specimens I found had 

 little projective " tubercles," from whieh a hiiir spr.uig, 



at the base, but the upper oval was certainly a walled 

 depression, and appeared so with half-inch, sixth, and 

 one-twelfth objectives. Two minute projections carry 

 the hairs at the tip. The legs are .short, with two claws 

 and minute pulvilli. The visibility of the oval wall and 

 dejiression depends upon its position under the micro- 

 scope. A full-faced view is plain enough ; a profile one 

 at best looks like a very slight notch. 



These Phylloxeree are, according to Buckton, " in a 

 qualified sense, exclusively oviparous, for the true o\Tim 

 applies only in strictness to the produce of the perfect 

 sexes." The pseudo-eggs laid here in August are thus 

 to be regarded as only more backward stages of the least 

 advanced young excluded by the aphides with their 

 limbs still folded up. 



The ringed forms, now on the oak leaves, are imagoes — 

 the Latin plural looks awkward, and the word may, I 

 hope, be treated as English. 



" Late in the autumn," says Mr. Buckton, " the second 

 brood of a late (winged) female occui', and these contain 

 eggs of different sizes, disclosing the true males and their 

 females." The Queen, or founder of a new brood, " is 

 the produce of the single egg laid by the true female." 

 The various forms are depicted in Mr. Buckton's work. 

 I do not know whether my specimens belong to the 

 sjiecies punctata, as they do not exactly correspond with 

 his figures. 



It is satisfactory that hitherto the English representa- 

 tives of the genus Phylloxera have not been guilty of any 

 serious injury like their relatives on the continent, which 

 played such havoc in the vineyards. Speckling some 

 leaves of our oaks is very different from the underground 

 assaults on the vine-roots, agrinst which no complete 

 defence has yet been found. The mouth of Phylloxera i^-- 

 like that of the aphis. 



The possessor of a microscope, unless very busy with 

 some special study, should always be on the look-oat as 

 an observer of what is going on in minute life. Some- 

 thing fresh and interesting is sure to be the reward. For 

 example, a glance at a mushroom-bed made in a frame 

 and kept dark with a cover, showed some small odd- 

 lookinc;- In-own bodies moving clumsily about as soon a.- 

 the li'jlit was alliiwfd to enter. They proved to be small 

 grei'ii llirs (ili| hi-s) — whose name I do not know — and 

 they wci'f so tliii-kly covered with mitts that they could 

 scarcely waddle, and not a bit of tin' '.in r- uld be 

 seen. Two sorts of mites were visiM. n , :,ijlass 



—one a Gamasid, like those common m, -Ml, iles, 

 brown, with hard skins, and about as 1- i i . ! - .Is of 



For permanent preservation, the Phylloxera and 

 mites were mounted in balsam. A small ring of 

 stout paper was gummed on to a irlass-slide, and ii. 

 minute quantity of (\.nad:i balsam I'lil Jm il,e middle. To 



t small bit of 

 rgs, as shown 



