p sam 2] 
XXVII. Remarks on the Pulvilli of Insects. By John Black- 
| wall, Esq., F.L.S. | 
Read, February 1, 1831. 
Ix the Physico-Theology of Dr. Derham, p. 363, note b, it is 
stated that ** diverse Flies, and other Insects, besides their sharp 
hook'd Nails, have also skinny Palms to their Feet, to enable 
them to stick on Glass, and other smooth Bodies, by means of 
the Pressure of the Atmosphere." This opinion, which appears 
to be almost universally adopted by the entomologists of the 
present day, has derived additional weight from the investiga- _ 
tions of Sir Everard Home, whose papers relative to this curious 
subject, illustrated by figures of the parts employed in climbing, 
engraved principally from drawings made by Mr. Bauer, are 
published in the Transactions of the Royal Society for 1816. 
These researches are regarded by Messrs. Kirby and Spence 
(see their Introduction to Entomology, vol. ii., Letter xx111.) as 
having * proved most satisfactorily, that it is by producing a 
vacuum between certain organs destined for that purpose and 
the plane of position, sufficient to cause atmospheric pressure 
upon the exterior surface, that the animals in question are en- 
abled to walk up a polished perpendicular, like the glass in our 
windows, or with their backs downward on a ceiling, without 
being brought to the ground by the weight of their bodies." To 
dissent from a theory so generally received, including among its 
advocates numerous illustrious names, may, perhaps, be deemed 
VOL, XVI. 3R presumptuous ; 
