1630 THE MYIASES AND ALLIED CONDITIONS 



Syrphid^: — 



Eristalis tenax Fabricius. 



arbustorum Fabricius. 

 dimidiatus. 

 Helophilus pendulinus Meigen. 

 Phorid^: — 



Aphiochcsta ferruginea Brunner. 



Phora rufipes Meigen ; synonym, P. palhpes Latreille. 

 Therevid^: — 



Thereva nohilitata. 

 Sepsid^e: — 



Piophila casei Linnaeus. 

 Drosophilid^: — 



Drosophila funebris Meigen, 



melanogastra Brunner. 



CEsTRiD^: — 



Spilogaster divisa Meigen. 

 Gastrophilus pecorum. 



Sometimes more than one species may be found in the same case. 



Rarer forms of myiasis are those by larvae of the TipuHdse, by 

 eggs and larvae of the Culicidae, and by the bots of Gastrophilus equi. 



The eggs or larvae of the above-mentioned flies enter the ali- 

 mentary canal with the food, especially with vegetable food in an 

 uncooked or partially cooked condition. Another method is for 

 the fly to deposit its eggs on the nostrils and lips of children, from 

 which they pass into the stomach and intestines, and a third method 

 is entry of the larvae into the rectum while using a privy. Intes- 

 tinal myiasis is not uncommon in cattle, both in the Temperate 

 Zone and in the tropics. There seems to be no doubt that the 

 larvae can live for a considerable time in the intestine, but the most 

 marked example of this is Aphiochcsta ferruginea Brun, which is 

 believed to be capable of passing through its entire life-cycle in 

 the human colon, because both newly hatched and fully grown 

 larvae were passed by a patient every two months for nearly a year, 

 notwithstanding the fact that nothing was said to be eaten which 

 could have contained either eggs or larvae. It is stated that species 

 of the Phoridae have been found in corpses, and it has been stated 

 that the living larvae, pupae, and imagines of species of Conicera 

 were found in numbers in a corpse exhumed at La Fayette, Indiana, 

 U.S.A., two years after burial. 



If there is any truth in this statement, it proves that the life-cycle 

 of these flies can be completed in a parasitic state, and would 

 explain the possibility of a patient suffering from myiasis for 

 twelve years, and during treatment passing 1,000 to 1,500 larvae. 

 Fenwick also reports cases in which it seemed probable that the 

 whole life-cycle was completed in man. It is obvious that these 

 statements require careful confirmation by other similar cases 

 before they can be accepted without reservation. 



Pathology. — The larvae usually cause gastro-intestinal symptoms. 

 Those of the Muscidae may cause little or no disturbance, but those 

 of the (Estridae and Tipulidae cause much disturbance. 



