462 
RHYNCHOTA. 
G. Jager's observations in " Wochenblatt fiir Land- und Forstwirth- 
schaft " reproduced, Das Ausland, xliii. (1870) p. 120 : cf. also op. cit. p. 405. 
Frauenfeld, Verb, z -b. Wien, xxiii. pp. 1-6, gives G. Pouchet's obser- 
vations on the economy of the insect (from the " Siecle," Sept. 29, 1872), 
which, however, appear to throw no fresh light on the subject. 
C. Y. Riley, Rep. Ins. Mo. v. pp. 57-73, reviews the experience of the 
past year, and does not alter any of his views. 
Planchon, C. R. Ixxvii. p. 871, gives the results of his American journey. 
An Acarus pursues the Phylloxera below the surface of the ground. 
J. Lichtenstein, ojj. cit. p. 342 et seq., gives a general summary of 
our knowledge of the economy of this insect. The American and Euro- 
pean species are identical, as are the leaf and root insects. The insect 
is very agile in all stages ; it becomes winged in the middle of June, 
and there are two different schemes of neuration, and two forms of the 
pupa. The number of moults, coupling (if any), and period of deposit- 
ing the eggs are unknown. 
M. Cornu, op. cit. pp. 656-663, states that winged individuals are 
more common than is generally supposed ; they certainly fly, and pro- 
pagate the species, and it is doubtful whether the various agents em- 
ployed do not drive them out, and so further spread the evil. 
Signoret, o/>, cit. pp. 343-346, considers Lichtenstein wrong in only 
ascribing 10 days as the period in which maturity can be reached : a year 
is required for perfecting each individual, which is polymorphous, and 
undergoes 6 moults or 10 periods. Three stages were observed in leaf 
galls, after which the insect went to the roots, where all the stages have 
been observed. Most of these statements are repeated by the author in 
Bull. Soc. Ent. Fr. (5) iii. p. cxxxix. Lichtenstein, in reply, cites a case 
of development in 9 days. 
Cornu, C. R. Ixxvii. pp. 710-714, thinks Signoret exaggerates the poly- 
morphism ; the maternal and tubercular types, identical in the early stage, 
are not so different in the adult as the later stages. 
Lichtenstein, Bull. Soc. Ent. Fr. (5) iii. p. clxiii., re-affirms the correct- 
ness of his statement as to the short period of evolution, giving instances 
observed by himself. Signoret, p. clxv., refuses to be convinced. Further 
disputations, I. c. pp. ccxxxv. & ccxxxvi. 
The first insects of the season appear about the third week in April ; 
p. 766. Fully developed individuals, very small in size, were observed 
at mid-day on 14th June, on the surface of the ground ; p. 1464. L. 
Faucon, C. R. Ixxvi. 
Transformations noted by Cornu, oj). cit. p. 947. The same author, 
C. R. Ixxvii., in a series of remarks upon the economy, &c., of this 
insect, states that the root and leaf species are identical (p. 190), that the 
insect voluntarily falls from the leaves to the ground, and that leaf- 
galls are rare in French vineyards, the leaves offering little nourishment 
(pp. 825-830). The production of leaf galls is discussed, pp. 879-883, 
and of root swellings, pp. 930-934, 1009-1015, 1088-1093, & 1168-1175 
(whatever the vine, the swellings are alike). A sexual individual was 
found just changing ; it had no sucker, and came from a batch of winged 
specimonK (p. 1015). The apterous form moults three times, both in 
