CHAPTER IV. 



Family TABANIDiE. 



" Horse-flies " ; " Mangrove-flies " ; " Seroots " (Seruts) or 



" Seroot-flies " ; " Hippo-flies." 



Plate II., fig. 9 — Plate XII., fig. 95. 



In Africa, as elsewhere, by far the greater number of species of 

 blood-sucking flies belong to this family, which occurs in all parts 

 of the world, includes the largest blood-sucking Diptera, and at 

 present consists of some 1600 described species, though many 

 synonyms are undoubtedly included in this total. The number 

 of species known to occur within the limits of the Ethiopian Region 

 is about 290, but it is certain that many new species have still to be 

 discovered and described. Most of the species belong to one or 

 other of the four principal genera, Tabanus, Hcernatopota, Pangonia 

 {sensu latiore), and Ghrysops ; of these Tabanus is much the richest 

 in species, and in respect of numbers the other genera follow in the 

 order given. The family is divided into the subfamiUes Tabaninse 

 and Pangoniinae, characterised respectively by the absence or 

 presence of a pair of spurs at the tip of the hind tibise. 



In appearance the larger Tabanidse are bulky-bodied flies, though 

 in the genus Hcematopota the body is generally narrow and elongate, 

 as is also the case in some of the species of Ghrysops. As regards 

 size, the African species vary in length from about 5 mm., as in the 

 case of a small specimen of Ghrysops inconspicua, Austen (Angola), 

 to about 27 mm., or over 1 inch, as in that of Tabanus grandissimus, 

 Ricardo (North-Eastern Rhodesia and Nyasaland Protectorate) ; 

 as in Diptera generally, dwarf specimens, due to failure of the food- 

 supply or other unfavourable conditions during the larval stage, 

 are not uncommon. The head, which is often large, is convex 

 anteriorly, and concave or flattened behind ; in the male it is 



