THE SCREW-WORM. 159 
distinct black stripes running from head toabdomen. When 
leaving the pupa the fly is gray, but very soon it assumes 
its glittering uniform, and the female is able to deposit her 
eggs the second day after emerging. 
The above life-history does not vary from that of any 
other flesh-or blow-fly. But the screw-worm attacks also 
living man, dogs, sheep, cattle, horses, and even fowls, and 
if it succeeds in forcing an entrance into the body of such 
hosts it causes the most excruciating pains, and not unfre- 
quently death. Its points of attack are the sheaths of male 
animals, the navels of new-born stock, and any abrasion of 
the skin. In man those suffering froma severe cold are most 
apt to be attacked by these flies, which were formerty called 
the ‘‘man-eating flies” (hominivoraw) on account of their de- 
youring man. In or near wounds found upon animals, or 
in nostrils and other openings, they deposit their eggs which 
immediately or very soon afterwards hatch. Theyoung and 
active maggots force their way into the flesh, feeding and 
growing as they go, and thus rapidly enlarge the sores. 
They are soon out of sight and revel now in living flesh, un- 
til the wounds enlarge to such an extent, if not discovered 
and treated in time, that the infested animal has to die. If 
such maggots enter the nostrils of man in numbers they are 
very apt to kill him unless steps are taken at once to remove 
them. 
In regions where such flies are common great careshould 
be taken not to expose wounds and sores, as these flies have 
been observed to deposit their eggs in them while they were 
being dressed. For the same reason persons should 
never sleep out of doors, nor unprotected by mosquito bars, 
wherever such flies abound. 
But it is not in the south alone that these flies occur. 
We have them in our state as well, though they have caused 
but few injuries, being here in fact rather beneficial as sca- 
vengers. Several cases are, however,on record,in which their 
larve have been found in the human ear.* In other cases 
fowls suffering from cold were killed by these maggots; they 
were eaten alive, so to speak. 

*Dr. Howard MclI. Morton, of Minneapolis, reports two cases which he treated 
in 1895. 
