364 Royal Society -—Letters from the 
tively free from hairs, and the relative motion of the remaining 
joints very much more limited.” 
My experiments on the mosquito began late in the fall ; and 
therefore I was not able to extend them to other insects. This 
spring I purpose to resume the research, and will experiment 
especially on those Orthoptera and Hemiptera which voluntarily 
emit distinct and characteristic sounds. 
PROCEEDINGS OF LEARNED SOCIETIES. 
ROYAL SOCIETY. 
December 17, 1874.—Joseph Dalton Hooker, C.B., President, in 
the Chair. 
Letters received from the Naturalists attached to the Transit-of- 
Venus Expedition at Rodriguez. 
Government House, Port Mathurin, 
Rodriguez, Noy. 2, 1874. 
Dear Sitr,—I write to give you a short account of my proceed- 
ings and success here so far, in my explorations of the Rodriguez 
bone-caverns. 
I must confess to a more or less degree of disappointment on 
my first inspection of the caverns; and you will understand the 
cause, I think, when I inform you that out of thirteen caves which 
I found on my arrival, and which I believed till lately to be the 
only ones, twelve bore evident, and some recent, signs of previous 
digging. However, I set to work at once, and, with much diligent 
search, had found five new caves by the time that we had finished 
the first thirteen. Out of these I have reason to believe that, 
in three of them, no mortal foot has ever been previous to mine; 
for the mouths of all were closed up by a falling-in of the rock ; 
and it was by this sign that I guessed at their existence. We 
had to work some time at all of them with a big iron mallet before 
entrance could be effected. In one of these caves I believe I found 
the bones of two Solitaires, without admixture of those of any other 
individuals. Of the truth of this I am pretty certain; for they 
were clearly the bones of a male and female which had fallen down 
into a cleft, from which egress to so unwieldy a bird was im- 
possible. 
Some of the bones had fallen into dust from exposure to the 
air, being only partially covered with sand, whilst others had been 
altogether removed: whether by water or not I could not say ; for 
I found no trace of its action there. The same cause, decay, which 
had nearly annihilated others might have entirely removed these. 
I found amongst these about thirty rings of the trachea or trachez. 
