Dob SON, on Lanp, or Lerp. 127 
[Under each of these limpet-like coverings there is usually 
found one or two little drops of a thickish, nearly transparent, 
and sweet fluids like honey, deposited there no doubt by the 
insect after enclosing itself, to become a resource probably in 
case of protracted imprisonment from any unfavorable state 
of the season as to temperature, humidity, &c. The insect 
would appear to be very susceptible to changes of tempera- 
ture, and perhaps to atmospheric influences generally ; for I 
have observed that, when a twig having leaves, with the 
white cones plentifully scattered over them, is brought in and 
kept for a few hours in a warm apartment, the perfect insects 
disengage themselves and are seen to flit about in numbers. 
—J. M.] 
The foregoing Paper, which was originally read before the 
Royal Society of Van Diemen's Land on the 11th of Septem- 
ber, 1 850, and published in the Papers and Proceedings^ of 
that body^ Vol. i, part iii, p. 235, was brought before the 
Microscopical Society by Mr. Dobson on the 30th of Aprils 
1856^ and he at the same time exhibited numerous and well- 
preserved specimens of the yellow variety of Lerp, a form 
which appears hitherto to have been undescribed. The 
variety examined and described by Dr. Anderson C^Edinb. 
New Philosophical Journal/ July, 1849) was of the white 
kind, and, as it would now appear, the product of a distinct 
species of Psylla. To Mr. Dobson, therefore, is due the credit 
of describing three distinct species of Psylla and two addi- 
tional forms of lerp, and of ascertaining, beyond doubt, the 
correctness of Mr. Newport^ s surmise that the substance 
itself is produced by the insect, and is not a mere exudation 
of the plant. Mr. Newport, however, seems to have been 
ignorant of the true position of the insect by which this pro- 
duction is aflPorded. 
The comparative novelty of the subject, and the importance 
of Mr. Dobson' s communication, which appears hitherto to 
have wholly escaped the notice of entomologists in this 
country, appear to aflPord sufficient reason for the republica- 
tion of his Paper in the ' Transactions of the Microscopical 
Society.' The figures, with the exception of figs. 8 and 9, 
are taken from those given in the original paper. The two 
additional figures were prepared from specimens of yellow 
lerp, kindly afforded to Mr. Busk by Mr. Dobson for ex- 
amination. 
