60 
BEITISH APHIDES. 
guide as regards tlie first set. Again, lie ranges tlie 
family into what he thought a more natural group- 
ing, dependent upon their supposed different modes of 
parturition. 
T rm • • • ( Contaminff tiie genera Aphis and 
1. The vivi-OTiparous | Lachnu!: 
2. The exclusively oviparous 
f Containing Tetraneura, Pemphigus, 
3. Tlie exclusively viviparous < Schizoneura, and probably For da 
(. and Trama. 
As to the OYO -viviparous character of the first group 
Kaltenbach truly says there can be no doubt. Ob- 
servations also, made up to the present time, would 
lead us to affirm the exclusively oviparous character of 
the second group ; but with reference to the exclusively 
viviparous character of the third group even Kaltenbach^' 
expresses some hesitation, and exception now must be 
taken to it, since some at least of the Pem^higincB 
are oviparous. Schizoneura and Phylloxera are also 
certainly oviparous. 
Kaltenbach restricts the Linngean genus Aphis to 
158 species, which, again, he subdivides into various 
headings, to which he simply attaches letters. Some 
of these smaller groups are, however, sufficiently 
distinct to induce Koch and later systematists to erect 
them into genera, after making certain modifications — 
a procedure which brings the old genus Aphis into a 
more manageable compass, although it remains still 
very numerous in species. 
Shortly after the appearance of Kaltenbach’s mono- 
graph Herr Katzeburgt published a quarto volume, 
with well-executed figures, on ‘ Forest Insects and 
their Injuries to Vegetation.’ In this work a con- 
siderable space is devoted to the description of Aphides, 
upon the economy of which he offers some good, but 
perhaps too diff’use, remarks. He gives an interesting 
account of the habits of that remarkable Chermes which 
Kaltenbach, Monograpbie ‘ Forstpflanznng,’ § 4, p. xxv. 
t J. J. C. Hatzeburg, ‘ Die Forst-Insecten/ &c., Berlin, 1844. 
