APHIDID.E. 
463 
galls and roots, at from 3 to 5 days interval (pp. 1276-1286). The pupa 
has 68 tubercles, and other particulars of that state are given (pp. 1330- 
1336). Hybernation of the root and leaf forms is discussed (pp. 1423- 
1430) ; the latter, after falling to the ground, does not at once develop, 
but waits for the early warmth of the next year. A comparative exami- 
nation is made of the young of both forms, of hybernating and sexual 
individuals. Those hybernating have no modifications of organization ; 
and the winter is a bad time for destructive agents, as the absorbing func- 
tions are suspended. Sexual individuals are not the young, but constitute 
a special form, differing from the produce of eggs of the ordinary 
apterous form, not only externally but internally (p. 1478 et seq.). The 
agility of hybernating individuals is discussed; their resuscitation can 
be produced artificially. They do not necessarily revive with reviving 
vegetation ; but revive earlier and multiply quicker in light soils and 
warm districts, and the plague therefore increases towards the south. 
The best time for their destruction is when they revive, and the plants 
are still dormant. 
Signoret, Bull. Soc. Ent. Fr. (5) iii. pp. Ixxviii.-lxxxiii., denies the 
discovery of the $ , either in France or America, and remains of opinion 
that the Phylloxera is neither the cause nor the effect of the disease of 
the vine. All the elaborate experiments and suggestions of remedies by 
careful observers are, according to him, founded on misconception. 
Giraud, I. c. p. Ixxxiii., considers, with him, that the arrest of sap-circu- 
lation has much to do with the disease. Cf. Gallois, Bull. Soc. Angers, ii. 
(1872) p. 86, on the question of the insect being cause or effect of the 
disease ; also Monier & Dupont, who adopt Signoret's view, and Lambot- 
Miraval, who opposes it : Bull. Soc. Hortic. Var, (7) i. No. 3. 
Lichtenstein, Bull. Soc. Ent. Fr. (5) iii. p. cxxi., replies to Signoret, 
aflB.rming that the insect is the cause of the disease, and that there are 
winged males, winged and apterous females, and perhaps a full grown 
apterous form. 
Guerin-Meneville, R. Z. (3) i. p. 415, and C. R. Ixxvii. p. 929, reiterates 
his conviction that the insect is not the cause but the consequence of the 
disease, and in this he is followed by Mares (a good abstract of the latter 
paper in R. Z. t. c. p. ii.). The best conditions of growth are accom- 
panied by the best conditions for resisting the Phylloxera ; bad growth 
and deteriorating causes aggravate its effects. Meneville's opinion is 
strongly contradicted by De Malegnane, C.R. Ixxvii. p. 1015 ; and by 
Cornu, op. cit. p. 1093. 
H. Mares, op. cit. pp. 1408-1411, discusses the propagation of the 
insect. Its great multiplication is the effect of general causes simul- 
taneously acting at various points. Vines should be better tended and 
strengthened. According to Faucon, op. cit. p. 1175, all manures and 
cultivators' methods are useless as preventives. 
On varieties of vines affected : Cornu, C. R. Ixxvii. pp. 766-770. 
The insect is excessively rare in some districts supposed to be infected : 
Signoret, Bull. Soc. Ent. Fr. (5) iii. p. cxxxix. V. Mayet, I. c. pp. cxl. & 
clxxi., in denial of this statement, refers to personal experience of the 
injuries done in these districts. 
