252 MAJOR W. S. PATTON. 



A phiochae fa. —The species of this Phorid genus can be recognised by their pecuhar 

 habit of moving in a jerky manner, and by the structure of the antennae and the charac- 

 teristic venation. A. xanthina [ferruginea) is a yellowish brown species, which is 

 widely distributed in the tropics, and its larvae cause cutaneous myiasis in man and 

 animals. A. rufipes is also a myiasis-producing species, but not so common as 

 xanthina. 



Accidental Myiasis-producing Flies. 



In this group are included an assemblage of unrelated Diptera — the larvae of which 

 occasionally find their way mto the intestinal tract of man. They normally breed 

 outside the human body in organic and vegetable matter, some of which is used as 

 human food, and people who are not particular with regard to what they eat become 

 infested. It should be clearly understood, however, that these flies do not intention- 

 ally deposit their eggs or larvae in certain human foods in order that their larvae may 

 reach the intestinal tract ; the food is merely their usual breeding ground. Although 

 many of the Oestridae live in their larval stages in the intestines of animals, they are 

 not accidental myiasis-producing flies, the intestinal tract is the only place in which 

 their larvae can reach maturity. 



So far as I can gather, intestinal myiasis is an uncommon condition, even in 

 countries like India, for in spite of the fact that I specially drew attention to it in 

 the circular mentioned above, which was sent to every medical and veterinary officer, 

 and in spite of the fact that some medical men have told me that it is very common in 

 parts of the country, I received such larvae from only two cases. 



The well known " rat-tailed " larvae of Eristalis tenax and Helophilus pendulus. 

 which normally live in foul ditch water, may be acquired by those, particularly 

 children, who drink such water, when they are likely to swallow large numbers of 

 small larvae of these drone-flies. In the same way, vegetables, such as lettuces and 

 mustard and cress, grown under insanitary conditions and eaten without being washed, 

 may contain eggs and larvae of Eristalis tenax and alhed species. The eggs and 

 larvae of Fannia and Anthomyia may also be swallowed intact in uncooked vegetables, 

 especially raw carrots. Onion fly larvae may be swallowed when eating diseased 

 spring onions, and species of Drosophila in over-ripe fruit, such as bananas and oranges. 

 Sarcophaga larvae are sometimes swallowed in imperfectly cooked meat, particularly 

 cold meat, and game that is commencing to decompose. In the case of Aphiochaeta 

 xanthina {ferruginea), the larvae of this small Phorid are most probably swallowed in 

 meats of all kinds, especially when beginning to decompose, as this substance is a 

 favourite breeding ground for the fly. One remarkable case has been published in 

 which the larvae, puparia and adults of this fly were passed in the faeces of a patient 

 for a considerable time, suggesting that the larvae were able to reach maturity in 

 the intestine, and the puparia remain alive, so that the adults could hatch out. 

 Recently in Coonoor, I attempted to infect monkeys by feeding them on large numbers 

 of eggs and larvae of this species, but although a most careful search was made for any 

 stages in their excreta, I was never able to recover either larvae, puparia or adults. 

 It would be worth while repeating this experiment, using only one monkey and making 

 a more thorough search than I was able to undertake. Such small larvae as those of 

 Aphiochaeta easily escape detection when the tray under such a monkey contains a 

 considerable quantity of remains of food in addition to its faeces. 



So far as I am aware, the larvae of the Calliphorinae are unable to live in the 

 intestine of man and animals, but in order to set aside any doubt on the subject I fed 

 a dog with large numbers of eggs and larvae of some common Indian species, but 

 not a single living larva was passed out, and it would appear that such larvae, w^hen 

 swallowed, soon die. But during the course of my enquiry into the myiasis- 

 producing flies of India, two masses of eggs of Chrysomyia megacephala were sent 

 me as having been passed out in the faeces of a patient. The eggs were intact, and 



