FLY. 
469 
cuate a fluid, which fixes her in such a manner as 
prevents her falling, without diminishing the facility 
of her progress. By some these sponges have been 
thought to correspond with the fleshy balls which 
accompany the claws of dogs and cats ; and that 
they enable the fly to proceed with a softer pace, 
and contribute to the preservation of its claws, whose 
pointed extremities would be soon impaired with- 
out this prevention. Besides these sponges her 
paws are shaded with a growth of hair, which she 
employs instead of a brush to clean her wings and 
eyes. If she is noticed at this employment, she will 
be seen first to clean her brushes, by rubbing one 
paw against the other, after which she draws them 
first over her wings and then under, concluding the 
whole with brushing her head ; and this operation 
she is obliged frequently to repeat in order to clear 
herself of dust, which if neglected would accumu- 
late, and injure her delicate frame. 
The trunk is composed of two parts, one of which 
folds over the other, and both of them are sheathed 
in the mouth. The extremity of this trunk is sharp 
like a knife, to enable the fly to cut what she eats. 
She likewise forms it into two lips, that she may the 
better take up proper quantities of food ; and when 
she has occasion, she employs it as a pump for 
drawing up liquors. 
