e out and drop to the ground
where they transform to the pupa and later to the adult fly. Of course
their presence in the wounds is very distressing to the infected animal,
and great suffering results. Slight scratches that might otherwise
quickly heal often become serious sores because of the presence of these
larvae.

Many cases are recorded of these flies laying their eggs in the ears or
nose of children or of persons sleeping out of doors during the day.
Especially is this apt to occur if there are offensive discharges which
attract the fly. In such cases the larvae burrow into the surrounding
tissues, devouring the mucous membranes, the muscles and even the bones,
causing terrible suffering and usually, death. The larvae in such
situations may be killed with chloroform and, if the case is attended to
before they have destroyed too much of the tissues, recovery usually
occurs.

The blow-flies (Fig. 26) (_Calliphora vomitoria_) and the blue-bottle
flies (Fig. 27), (_Lucilia spp._) and the flesh-flies (Fig. 28)
(_Sarcophaga spp._) all have habits somewhat like the screw-worm fly.
Any of them may lay their eggs in wounds on man or animals with the same
serious results.

The flesh-fly instead of laying eggs deposits the living larvae upon meat
wherever it is accessible, and as these develop with astonishing
rapidity they are able to consume large quantities of flesh in a
remarkably short time. In this way they may be of some importance as
scavengers, but it is better to get rid of the waste in other ways than
to leave it for a breeding-place for flies that are capable of causing
so much damage and suffering.

Not infrequently the larvae of certain flies are to be found in the
alimentary canal where as a rule they do no particular damage.
Altogether the larvae of over twenty different species of flies have been
found in or expelled from the human intestinal canal. In Europe, the
majority of these larvae belong to a fly which looks very much like the
house-fly except that it is somewhat smaller and so is often known as
"the little house-fly" (Fig. 29) (_Homalomyia canicularis_). The same
species is very common in the United States, frequently occurring in
houses. Under certain conditions it may even be more abundant than the
house-fly. It is believed that the larvae in the intestinal canal come
from eggs that have been deposited on the victim while using an outdoor
privy where the flies are often very abundant. Insta