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UNITED STATES NATIONAL MUSEUM BULLETIN 224 



Loew, two large staphylinid beetles, and a large, con- 

 spicuous iclineumonid-type wasp. In southern Arizona 

 Blephareplvm secabilis Walker occurs in company with 

 a similarly colored sphecid wasp upon which it preys; 

 the wasp is a little larger than the fly. 



Cryptic coloration exists in some forms. Desert spe- 

 cies especially tend to match the sandy background and 

 many Laphriini and species of the Atomosini and 

 species of Andrenosoma Rondani match the bark on 

 which they rest. 



Death feigning has been observed in some captured 

 asilids and has been remarked by Teale. I have noted 

 that Proctacanthus milbertii Macquart may remain in 

 catalepsy from several seconds to several minutes. 

 How often this state is reached or occurs under natural 

 conditions is not known. 



Zoogeographic Relationships 



The Asilidae are world wide in distribution. The 

 majority of the species and genera are found north of 

 the southern tropic, the reduced land masses below this 

 latitude producing fewer. Certain groups signifi- 

 cantly characterize certain regions. No endemic or 

 introduced species are known from the Hawaiian Is- 

 lands but Laphriini and some other types occur 

 sparsely on the smaller island groups. All larger is- 

 lands south of Asia have a rather abundant asilid 

 fauna, and a few extend onto Fiji, Samoa, New Zea- 

 land, and one species is found on Christmas Island. 



It is possible to point to genera which constitute 

 characteristic features of certain regions. In the Neo- 

 tropical region the Megapodinae are unique. In the 

 same region we find a concentration of the Atomosini 

 and the Holcocephala Jaennicke branch of the Dama- 

 lini, as well as the prominent, southward extension of 

 Diogmites Loew of the Dasypogoninae and of Nerax, 

 new genus, from the Asilinae. Probably Mexico and 

 northern South America can be regarded as the home 

 of the last two named genera; however, the United 

 States is very rich in representatives of both. 



In the northern hemisphere the genera Laphria 

 Meigen, Cyrtopogon Loew, Lasiopogon Loew, and the 

 genus Asilus Linne, sensu lato, predominate. The 

 Neolophonotus Engel group of the Asilinae and the 

 genus Microstylum Macquart of the Dasypogoninae are 

 especially well represented in South Africa. In south- 

 ern Asia and the larger South Pacific islands, the beau- 

 tiful, metallic flies of the genus Maira Schiner replace 

 Laphria Meigen. Oddly, the Laphriinae have pro- 

 duced the metallic species in the genus Lampria Mac- 

 quart in the New World tropics, which seem to parallel 

 Maira Schiner. 



Certain rather numerous, small areas or pockets of 

 concentration in terms of genera and subgenera appear 

 as a result of mapping the more than 4700 species of 

 Asilidae to the point given for the type species. I 

 refer to these regional spots as regions of concentration. 

 I have attempted to show approximately these regions 

 of concentration as small, shaded areas on the map in 



text-figure 7. The numbers on these dark areas refer 

 to how many genera or subgenera are associated with 

 each area, and which may be regarded as endemic for 

 these areas. Many of the small, shaded areas cor- 

 respond to the floristic regions of the world as illus- 

 trated by Good in Map 4 of his work "The Geography 

 of the Flowering Plants" published in 1947. The 

 wider, unshaded areas on the map indicate the addi- 

 tional genera which have a wider distribution. No 

 implications of origin are made for the genera of these 

 areas, although, doubtless, most of these genera had 

 their beginnings there. The generic totals given in 

 the tables below for these small areas do not include 

 other genera which occur hi the same region, but which 

 also have a widespread, or more or less continent-wide, 

 or world-wide distribution. 



There are 10 asilid genera of nearly world-wide 

 distribution: These genera are Laphystia Loew, 

 Stichopogon Loew and Saropogon Loew of the sub- 

 family Dasypogoninae; Leptogaster Meigen of the 

 Leptogastrinae; Laphria Meigen, Andrenosoma Kon- 

 dani and Pogonasoma Rondani of the Laphriinae; and 

 Ommatius Wiedemann, Promachus Loew, and Neo- 

 itamus Osten Sacken of the Asilinae. Of these genera 

 Saropogon and Laphria are excluded from South 

 America and Laphystia is excluded from Australia. 



As examples of such areas of concentration, the 

 Chilean region has 16 characteristic genera; the Ama- 

 zonian area has 7 such genera ; what is here termed the 

 La Plata region, including the eastern part of South 

 America south from Rio de Janeiro as far as Buenos 

 Aires, has 33; and other areas are shown on the map. 

 In North America, curiously, there appear to be 18 

 characteristic genera, of these 13 genera characterize 

 the south-central part of the United States west of the 

 Mississippi River and only 3 characterize the States 

 east of this river. South Africa shows 38 character- 

 istic genera, of which 14 might be called genera found 

 in the Cape region. There are, in addition, 9 other 

 genera peculiar to central Africa. The Mediterranean 

 area has 20 genera and the Transcaucasus has 15 

 genera, both of these areas being exceptionally interest- 

 ing in terms of their special asilid fauna. 



Especially interesting are the population values in 

 terms of genera and species for small regions and 

 specific localities. Lists for specific localities are very 

 scarce or wanting. For Oxford, Mississippi, in a 

 3-mile radius I have found 49 species in 28 years of 

 collecting. My list of Asilidae from Mississippi is 

 still quite incomplete, but will probably compare well 

 with the Florida list of 96 species by Bromley (1950). 

 Bromley (1934) listed 161 species from Texas, a list 

 which is also incomplete and reflects at once the large 

 size of that State and the increasing aridity. James 

 (1938) listed 122 species from Colorado. Johnson 

 (1925) listed 45 species from Maine, 72 from Massachu- 

 setts, and Bromley (1946) listed 68 Asilidae from Con- 

 necticut. Bromley (1950) listed 94 species from Ohio, 

 and in 1932, listed 28 species from Patagonia and South 

 Chile. Verrall (1909) listed 23 species from England, 



