Xii Warble fly. 



central hole of tlie swelling, with its feeding end, which cannot he 

 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 mouth-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-hole, 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 bauds 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 (Estnis (that is, Bot or Warble) maggots workmg below the skin, 

 takmg 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 (Esirus 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 Eegiment, 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 ilchimj romid it at times was intense. 



