Introduction 



The robber flies, or Asilidae, comprise one of the 

 largest and most abundant families of present day 

 insects. Distributed through all parts of the world, 

 over 400 genera and subgenera have been proposed and 

 about 4,761 species are known. In addition, 18 genera 

 and 39 species have been described from the Eocene, 

 Oligocene, and Miocene; 15 of these genera are also 

 Recent. Because of their predatory habit of feeding 

 on other insects and their voracious appetites, they con- 

 tribute to the maintenance of the natural balance among 

 insect populations. To some extent, parasitic wasps 

 and flies are taken by them, but much of their prey 

 consists of plant-feeding insects. Certain species are 

 known to seriously deplete the populations of apiaries. 

 The adults are, with few exceptions, active flies, of con- 

 siderable size and readily attract attention. 



Hermann Loew in 1847 began a world study of the 

 Asilidae; his publications on this project continued 

 until 1874. During the last half of the nineteenth 

 century, many dipterists contributed to our knowledge 

 of this family. Today, much excellent work is being 

 done regionally on the Asilidae. The present study 

 integrates all previous work, in order that a basis for 

 a world concept of the group may be laid. 



It is hoped that this study will afford persons in 

 widely separated parts of the world means of identi- 

 fication of their own fauna and a knowledge and 

 appreciation of the f auna of other regions. Considera- 

 tion has been given to the evolutionary trends and 

 distribution of the genera, tribes, and subfamilies. 



History of Studies 



Linnaeus (Linne; 1758), in his tenth edition of 

 "Systema naturae" erected the genus Asilus, ascribing to 

 it 11 species, and added 4 others in his twelfth edition 

 (1767) of the same work. Of these 15 species included 

 in the genus by Linne, 10 have been assigned to other 

 genera, 2 remain in Asilus and 3 cannot be recognized 

 with certainty, because of the brevity of the original 

 descriptions. A list of reassignments of Linne's species 

 is given under the subfamily Asilinae. His species 

 Asilus crabroniformis (1758), stands as the type of the 

 genus Asilus and the type of the family Asilidae. Fam- 

 ily status is credited to Leach in Samouelle (1819). 



J. C. Fabricius, in five publications from 1775 to 1805, 

 describes 76 exotic and European species and erected the 

 genus Damalis. Wiedemann, from 1817 to 1830, de- 

 scribed 235 species, many of which were exotic. He 

 proposed 3 genera, all of them used today. Meigen, 

 1800 to 1838, described many species in his treatment of 

 the European asilids and in an early work of 1803 

 erected 4 genera, 3 of which now represent subfamilies. 



About the middle of the nineteenth century, a number 

 of dipterists made significant contributions to the study 

 of the family Asilidae; among them were Loew, 

 Macquart, Walker, Rondani and Bigot, but none more 

 important than the indefatigable Loew, who, besides 

 describing great numbers of species, proposed 83 genera, 

 75 of which are still recognized, although 5 of these 

 names required changing on account of preoccupation. 

 Later, considerable work was done by Schiner, Willis- 

 ton, Lynch Arribalzaga, Philippi, Jaennicke, Roeder, 

 and Becker. By 1900 a total of 254 genera had been 

 proposed, of which 170 are still valid. During the first 

 half of the twentieth century, many careful students of 

 the Asilidae have appeared. Very excellent contribu- 

 tions have resulted from the studies of Hermann on the 

 South American genera, Engel in his monumental vol- 

 ume on asilids in Lindner's "Die Fliegen der palaeark- 

 tischen region" and Efflatoun's "A monograph of 

 Egyptian Diptera. Family Asilidae," besides the work 

 of Oldroyd, Becker, Bezzi, and Ricardo. White made 

 pioneer studies of Australian asilids and was lafer 

 followed by G. H. Hardy. 



In North America, Hine became early interested in 

 this family. Shortly thereafter Curran, Bromley, 

 Pritchard, Wilcox, James, and Martin industriously 

 contributed many papers; and recently Carrera has 

 made important contributions to a study of the South 

 American fauna. A recital of past studies of Asilidae 

 reads very much like a directory of dipterists, so popu- 

 lar has been this family and I have for reasons of space 

 omitted many well known dipterists who made briefer 

 contributions. The student is referred to the bibliog- 

 raphy for the work of others to whom credit is also 

 due. . 



The bibliography covers a span of 200 years and con- 

 tains the work of about 387 authors and 1344 titles. 



