f butcher's
meat laid on the window sill, in front of my writing table, will be less
offensive to the eye and will facilitate my observations.

Two flies of the genus Sarcophaga frequent my slaughter yard: Sarcophaga
carnaria and Sarcophaga haemorrhoidalis, whose abdomen ends in a red
speck. The first species, which is a little larger than the second,
is more numerous and does the best part of the work in the open air
shambles of the pans. It is this fly also who, at intervals and nearly
always alone, hastens to the bait exposed on the windowsill.

She comes up suddenly, timidly. Soon she calms herself and no longer
thinks of fleeing when I draw near, for the dish suits her. She is
surprisingly quick about her work. Twice over--buzz! Buzz!--the tip of
her abdomen touches the meat; and the thing is done: a group of vermin
wriggles out, releases itself and disperses so nimbly that I have no
time to take my lens and count then accurately. As seen by the naked
eye, there were a dozen of them. What has become of them? One would
think that they had gone into the flesh, at the very spot where they
were laid, so quickly have they disappeared. But that dive into a
substance of some consistency is impossible to these newborn weaklings.
Where are they? I find them more or less everywhere in the creases of
the meat; singly and already groping with their mouths. To collect them
in order to number them is not practicable, for I do not want to damage
them. Let us be satisfied with the estimate made at a rapid glance:
there are a dozen or so, brought into the world in one discharge of
almost inappreciable length.

Those live grubs, taking the place of the usual eggs, have long been
known. Everybody is aware that the flesh flies bring forth living
maggots, instead of laying eggs. They have so much to do and their work
is so urgent! To them, the instruments of the transformation of
dead matter, a day means a day, a long space of time which it is all
important to utilize. The greenbottle's eggs, though these are of very
rapid development, take twenty-four hours to yield their grubs. The
flesh flies save all this time. From their matrix, laborers flow
straightway and set to work the moment they are born. With these ardent
pioneers of sanitation, there is no rest attendant upon the hatching,
there is not a minute lost.

The gang, it is true, is not a numerous one; but how often can it not
be renewed! Read Reaumur's description of the wo