Entomological Society. 211 
The Rev. F. W. Hope exhibited a series of drawings of the trans- 
formations of various Indian Lepidoptera, made by Mr. Ezra Downes. 
The following memoirs were read :— 
«On the Existence of Thoracic Branchie in the Imago state of the 
Neuropterous genus Pteronarcys.’”’ By George Newport, Esq., Presi- 
sident E.S. (Annals of Natural History, vol. xiii. p. 21). In refer- 
ence to this memoir Mr. Westwood stated, that he had detected 
some thoracic appendages in the genera Ptychopteryx and Heliophi- 
lus, described and figured in his ‘ Introduction to the Modern Clas- 
sification of Insects,’ vol. ii. fig. 126, 7. p. 526. note f, and p. 557, 
which he considered to be analogous to the branchie discovered by 
Mr. Newport in Pteronarcys. The latter gentleman however objected 
to this analogy, as the organs in question existed simultaneously with 
the true spiracles. Mr. E. Doubleday, in reference to a suggestion 
made by Mr. Newport, stated that he had always noticed that the 
North American species of Chauliodes are on the wing in rainy 
evenings. 
“On the proceedings of a species of Trombidium which infested 
the Plane-trees in the Regent’s Park during the past summer.” By 
George Wilson, Esq., M.R.C.S. Communicated with additional 
notes by A. White, Esq. 
At the beginning of September Mr. Wilson’s attention was directed 
to the trees, several cf which had the trunks and branches entirely 
or partially covered with a very delicate web, upon which myriads 
of a small Arachnidous insect were running to and fro, extending 
their webs rapidly along the branches. ‘The web was so fine as to 
appear like a thin compact layer of varnish upon the stems of the 
trees; and from the vast numbers of the insects, the grey web ap- 
peared dusted with a reddish powder, the insects being of a light 
orange colour inclining to brown. From the web so completely en- 
veloping the tree and obstructing the vital influence of the atmo- 
sphere, the leaves became withered and fell. This was especially 
the case with the plane-trees, the elms and horse-chestnuts being 
free from them. ‘The weather for several days previously and sub- 
sequently was fine and sultry, but in the course of a few daysa heavy 
fall of rain, accompanied by a thunder-storm, put a stop to the injury 
by destroying the insects. On placing a portion of the web with 
its inhabitants in a bottle, Mr. Wilson observed that in about an 
hour a beautiful transparent cylinder had been spun within the bottle 
from the base of the top, impinging against the side of the bottle at 
about half its height; and it was remarkable that there was not a 
single thread stretched across the inside of the cylinder, nor was a 
single insect enclosed within it. Having completed their first cylin- 
der, they threw a second around it more slender than the former, 
leaving only asmall interval between them. 
Mr. White considered the species to be the Trombidium tiliarium, 
Herm., or an allied species, and distinct from the Acarus telarum, 
Linn., and Trombidium socium, the habits of which, as described by 
Hermann, were mentioned by Mr. White. 
Mr. Walton informed the Meeting that a specimen of the true 
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