CHAPTER XII 



Myiasis — Types of Injury and Life History, and Habits of Species 



Concerned^ 



F. C. Bishopp 



Myiasis is a term applied to" the attack of living man or animals by fly 

 larvae. The medical profession usually assigns specific names to the 

 infestations according to their location — as dermal (in or under the 

 skin), nasal (nose infestation), auricular or otomyiasis (ear attack), 

 intestinal, etc. These names are not entirely satisfactory as often one 

 form will develop into another or one species of larvae may be concerned 

 in attacks in many different regions. And again several species may 

 attack the same region but produce different types of injury, or the 

 point of attack may vary with the stage of the larvae. 



Any attempt to classify the different types of myiasis according to 

 character or place of attack or species of fly concerned seems to have 

 its objections and difliculties. For convenience in discussion an attempt 

 is made to divide the subject from the standpoint of method of attack 

 into the following groups : 



First, TISSUE-DESTROYING FORMS, including those species 

 which are ravenous feeders and destroy living tissues. For example the 

 screw-worm, Chrysomya macellaria Linnaeus. The species which are 

 included in this group with the exception of WoMfahrtia mugnifica 

 Schiner attack living animals secondarily, the main source of breeding 

 being in dead animal matter. 



Second, SUBDERMAL MIGRATORY FORMS which are parasitic 

 in animals or man and occur during the major part of their lives beneath 

 the skin. For example, the ox warble, Dermatobia or "torcel," in 

 man, etc. 



Third, LARV^ INFESTING THE INTESTINAL OR UROGENI- 

 TAL TRACTS. These usually feed to a lesser or greater degree on food 

 or excrementitious matter within the body. For example the larvse of 

 the latrine flies of the genus Fannia and of certain flesh flies of the family 

 Sarcophagidae. Infestations largely accidental, except horse bots and 

 related species in animals which are truly parasitic. 



Fourth, FORMS INFESTING HEAD PASSAGES. True parasites 

 *This lecture was presented November 18 and distributed December 20, 1918. 



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