12 
WARBLE FLY. 
central hole of the swelling, with its feeding end, which cannot be 
called a head, in the foul matter of the cell, and the black spots, which 
are the ends of its breathing-pores, in the tip of the tail above. At 
this full-grown, or nearly full-grown, condition, removal of a maggot 
from the cell, and careful watching of it for a little while in the hand 
will show the powers with which it is furnished for its own safety, and 
great disservice to ourselves. 
A maggot at this stage, besides the power given by its strong coat 
of muscles (see fig. 9) of contraction and expansion, which may be 
observed in protruding and withdrawing the mouth-end with the regu¬ 
larity of pulsation, has a power of movement so definite that it can 
drag itself along at the rate of three times its own length in two 
minutes, and with a definite method of progression. The moutli-end 
I observed to be somewhat raised, and the creature appeared to move 
with as settled a purpose as other grubs and caterpillars. Whilst still 
inside the warble, of course this power is unimportant, so far as 
“travelling” far is concerned; but it is very important as to giving it 
power to move up and down at pleasure in the warble-liole, causing 
constantly recurring discomfort. Externally at this stage the skin of 
the maggot is furnished with a much larger amount of prickles, 
arranged in more numerous bands than are noticeable in the previous 
stages. These prickles are now, I found, strong enough to cause an 
unpleasant sensation when the maggot crosses the hand, and, as well 
as the muscles, play an important part in its power of movement in its 
cell, and in its powers of irritation. 
With regard to what the sensation might be caused by just one or 
a few (Kstrus (that is, Bot or Warble) maggots working below the skin, 
taking the subject quite independently of the graver considerations 
involved, as the animals could not explain this, and I was aware that 
a somewhat similar attack occurs not unfrequently to the human 
subject in the more central parts of America, I wrote on the subject to 
Mr. Everard im Thurn, then resident in British Guiana, and well 
known for his scientific attainments, and also as the scaler of the 
(previously supposed inaccessible) mountain of Roraima, in those 
regions. Mr. im Thurn replied that he had himself suffered from the 
attack of warble-maggot a little below the knee, and he described the 
pain as not being constant, but from time to time quite sharp, as if 
the maggot was screwing itself round in its hole. This gives an idea 
of one kind of pain connected with attack of CEstrus larva. Further, 
in communication with Mr. J. S. Macadam, Army Surgeon, British 
Guiana, he mentioned one case of a black soldier of the 1st West 
Indian Regiment, who presented himself, complaining of a sort of 
large boil with hard edges on the front of the throat, which had broken 
and would not heal up, and that the itching round it at times was intense. 
