226 MYIASIS 



the thigh, and during successive days it appeared at different 

 points along a course up the abdomen, under the axilla, over the 

 scapula, up the right side of the neck, irregularly about the scalp, 

 finally passing back of the ear and to the submental region, 

 which it reached about two months after its first appearance ; 

 there it remained stationary." Another lump also migrated in 

 the same manner about three or four inches a day. 



One larva was extracted and identified by Stiles as " the 

 larva of Hypode^nna lincata in the second stage." 



The larvae of H. bovis and H. diana have also been observed 

 in man. 



E. Intestinal myiasis due to larvce in the alimentary canal. 



Dipterous larvae may occasionally find their way into the 

 alimentary canal, usually by accident, and may be vomited up 

 or expelled in a living condition by the bowel. Many instances 

 have been recorded in various parts of the world, especially in 

 the tropics, and several have been recorded in England. Austen 

 (19 1 2) gives a list of cases in which the larvae were submitted to 

 him for determination, and from time to time other workers have 

 published their experiences. The presence of the larvEe in the 

 stomach is sometimes indicated by nausea, vertigo and violent 

 pains ; if present in the stomach the larvct may be expelled by 

 vomiting. If they occur in the intestine they are expelled with 

 the faeces, and their presence is sometimes signalized by diarrhceal 

 symptoms and abdominal pains, or more rarely by haemorrhage. 

 In several of the recorded cases the presence of the larvae has 

 not given rise to symptoms of any kind, and they have been 

 noticed first in the stools by accident. Whether previous in- 

 convenience is caused or not the patient is usuall)' greatly 

 alarmed by the passage of the larvae. 



Since the great majority of cases of intestinal myiasis in 

 England are due to the presence of the larvae of F. scalaris or 

 F. caniciilaris, an account of infection with these larvae will be 

 given first, and then the cases due to other larvae mentioned. 



