4 MISC. PUBLICATION 631, U. S. DEPT. OF AGRICULTURE 



adult specimens of almost all the species treated here have been avail- 

 able, but the situation in regard to the larvae has not been so fortunate. 

 For brevity in treatment, only those characters considered to be diag- 

 nostic are discussed in the descriptions of both larvae and adults. 



In most species, only the mature larva is described, partly because of 

 the limitations of the published records and partly because that stage 

 is the most significant, the earlier stages in many flies being of short 

 duration. When, however, there are sufficiently well-marked charac- 

 ters for the earlier stages, or when they are of more importance, as in 

 Oestrus and Gasterophilus. these are given due consideration. 



Some may question the value of detailed citation of political units 

 under the heading of geographical distribution, where, it may be felt, 

 general statements might suffice. It is the author's experience, how- 

 ever, that this detailed information is often requested, and is much 

 harder to trace in the literature than is almost any other body of facts 

 relating to the problem at hand. 



The total known geographical distribution for each species is given, 

 not merely the records for myiasis. The lists have been prepared from 

 published records, those which are clearly or probably erroneous being 

 omitted, and from specimens present in the collection of the United 

 States National Museum or determined by the author from other 

 sources. Geographical names have been standardized according to 

 those used by the National Geographic Society, Washington, D. C, 

 in the World Map published December 1943 ( international boundaries 

 as of September 1, 1939), except that the boundaries of Austria and 

 Czechoslovakia prior to the German invasion and the boundaries of 

 Ethiopia prior to the Italian invasion are accepted. When greater 

 detail was necessary, other maps of the Society for the same general 

 period were consulted. For convenience, political units were grouped 

 according to the zoogeographical regions of Wallace rather than ac- 

 cording to continents. When one political unit falls within two zoo- 

 geographical regions, it is considered under the region that contains 

 the larger part : for example. China is considered Palaearctic, India 

 Oriental, and Mexico Neotropical. 



Some of the most important general works on myiasis are those by 

 Dove (34) 2 for the United States, Mazza and coworkers (87) for 

 Argentina, Mumford (91) for England, Lampa (79) for Sweden, 

 Portchinsky (US, 116, 117, 118,) for Russia, Onorato (96) for 

 Tripolitania, Roubaud (126) for Africa, Lewis (83) for Kenya, and 

 Porter (119) and Bedford (13) for South Africa. Patton (100, 101) 

 -deals with the subject of myiasis in general, but his work, particularly 

 the second paper, is of especial value in relation to the Indian fauna. 



The taxonomic literature covering the groups treated in this work 

 is voluminous. Important pertinent citations are given in the proper 

 places in the text, but a few general works and series of works deserve 

 mention. C. H. Currairs "The Families and Genera of North Ameri- 

 can Diptera" (New York, 1934) gives keys to the genera of Diptera 

 occurring in North America, with numerous illustrations and other 

 valuable material. C. H. T. Townsend's "Manual of Myiology," in 

 12 parts, (Sao Paulo, Brazil, 1934-42), is indispensable to the study 

 of the muscoid flies; it deals, however, only with genera (used in 

 a greatly restricted sense) and higher categories. "Die Fliegen der 



Italic numbers in parentheses refer to Literature Cited, p. 164. 



