FA.MILV .MKTUrilD.K — THE FLESH FLIES 403 



As indicated in tlie introduction I consider Mijasis in man is gener- 

 ally an accidental occurrence. There is evidence that it may occur 

 under conditions where an open wound is not dressed and incidents 

 of this kind were not rare during the World War. Indeed, the condi- 

 tion of maggot-infested wounds led to the discovery of the value of flies 

 as an aid in curing serious wounds and also in the treatment of Osteo- 

 mi/eJitis. It is true that some medical men express doubt about the 

 efficacy of the maggot treatment of this disease but the evidence seems 

 to be in its favor. The maggots feed, for the most part at any rate, 

 only on decayed tissue and the bacteria present in the w^ound. Whether 

 healing results from the consumption of bacteria or the secretion of a 

 substance stimulating the growth of new flesli is immaterial. 



The larva? of the Screw Worm Flics {CochHomiiia maceUaria and 

 americana) occasionally attack man. The eggs are laid in open wounds 

 or nasal or other discharges from the body and the larvie quickly bore 

 into healthy tissue. From fifty to more than two hundred eggs may be 

 laid at a time. There have been a numl^er of fatal cases in the United 

 States while, in the tropics, death from the attacks of the maggots is 

 said to be not rare. Sheep and range animals are normally attacked 

 when wounded or when the wool l:)ecomes fetid due to filth. 



The classification of the group is in chaotic condition. A great 

 many genera have been proposed upon characters possessed by one sex 

 or the other and upon characters which are apparently of not more than 

 specific or group value and which, when large collections are studied, 

 are found to be entirely unsatisfactory. There are no doubt several 

 North American genera not included in the key but, without specimens, 

 it is impossible to locate them. I have included all the North American 

 genera known to me but am acquainted with several others occurring in 

 South America which may possibly occur in the North American Tropics 

 although there are, as yet, no records. 



There are three papers which will be found most useful in the study 

 of the insects belonging to this family, published by Aldrich*, Allenf 

 and Shannon^. In the former many of the specific names have been 

 replaced by older names as the result of a study of the types of species 

 described by older authors. For these corrections see Aldrich*. 



It is unfortunate that the name of this family must be changed 

 to ]\Ietopiid«, but since there has been no previous grouping of the 

 included genera into a single family the shock should not be great. The 

 basic use of Miltogramma for tribal name has always been erroneous 



* 1916, Sarcophaga and Allies. (Thomas Say Foundation. Vol. i). 1930. Notes on Types, 

 etc.. Pro;;. U. S. N. M., Ixxviii, Art. 12. 



t 1926, N. Amer. Miltofcrammini, Proc. U. S. N. M., Ixviii, Art. 9. 



± 1926, Syn. Amer. Calliphoridie, Proc. Ent. Soc, Wash., xx.-iii, pp. 115-139. 



