938 REPORT OF THE HARVARD AFRICAN EXPEDITION 
Tabanus secedens Walker 
Tabanus secedens Walker, 1854, ‘List Dipt. Brit. Mus.,’ V, Suppl. 1, p. 224 (new name for 7’. 
tibialis Walker). Austen, 1909, ‘Illustr. African Blood-Suck. Flies,’ p. 96, Pl. VU, fig. 54 (¢ ). 
Tabanus tibialis Walker, 1848, ‘List Dipt. Brit. Mus.,’ I, p. 162 (9; West Africa). Not Tabanus 
tibtalis Macquart, 1845. 
Tabanus blanchardi Surcouf, 1907, Archives de Parasitologie, XI, p. 473, Pl. IX, figs. 3 and 4( 9; 
“British Guinea, between 6° N. and 8° N., and 3° E. and 5° E.”; this is in Southern 
Nigeria). 
Tabanus brunnescens Ricardo, 1908, Ann. Mag. Nat. Hist., (8) I, p. 322 ( 9; Gold Coast). 
Tabanus garonensis Macquart, 1855, ‘Dipt. Exot.,’ Suppl. V, p. 23 ( 2; Gaboon). 
Tabanus gabonensis Bigot, 1858, in Thomson, Archives Entomol., II, p. 348 (9 ). 
? Tabanus ignotus Surcouf, 1909, ‘Et. Monogr. Taban. Afrique,’ p. 223, Pl. III, fig.5(#; Brazzaville, 
French Congo). Not Tabanus ignotus Rossi, 1790 ( = T'. gigas Herbst, 1787). 
Liperta. — Banga, October 1926. Bomboma (Moala), October 31, 1926. 
BeLci1an Conco. — Lokutu, December 23, 1926; Budja Libala, Decem- 
ber 25, 1926; Lisala, December 26, 1926; Bolengi, December 28, 1926; Lu- 
longa, December 1926; Bumba, December 27, 1926; Ukaturaka, December 
24, 1926; Barumbu, January 6, 1927; on the railroad between Stanleyville 
and Ponthierville, January 15, 1927; Coquilhatville, December 20, 1926; Isangi, 
January 8, 1927; Irebu, December 17, 1926; Nouvelle-Anvers, March 15, 1915; 
Lubutu, January 30, 1915; between Penge and Irumu, March 1, 1914. Uele 
District (J. Rodhain). Basoko; between Bolobo and Lukolela; Stanleyville, 
twenty-five females and nine males, as prey of Bembix bequaertt Arnold var. 
dira Arnold (H. Lang and J. P. Chapin). Moto (Thélie). Bongo (J. Maes). 
Kabambare (Flamand). Miao (Baugniet). Mobeka (Prince Albert of Belgium). 
Buta (de Calonne Beaufaict). Mawambi (C. Christy). 
This common and widely distributed species is rather variable in size and 
color markings, so that it readily lends itself to the making of so-called “‘spe- 
cies’? based upon extreme individual variations. Sureouf has attempted to 
distinguish between T’. secedens, T. blanchardi, and T. gabonensis (1922, ‘Voy. 
M. de Rothschild Ethiopie, Rés. Scientif., Anim. Artic.,’ II, pp. 855-856), but 
the characters which he uses in his key will hardly serve the purpose.' 7’. blan- 
chardi was evidently based upon unusually small specimens with a well-marked, 
median, pale stripe on the abdomen and with the lateral markings obsolete. 
These three peculiarities are found, in various combinations, among a large 
series of specimens taken on the Congo River. The distinction which Sur- 
ecouf draws between 7’. gabonensis and 7’. secedens is even more elusive. He 
says that in the former the median stripe of the abdomen is, as a rule, con- 
tinuous, while there are no lateral spots (‘‘Bande médiane généralement con- 
tinue. Pas de taches sous-médianes’’). Both these characters again are present 
or absent in specimens of 7’. secedens taken at the same spot and the same day. 
The different appearance of the specimens is undoubtedly due in many eases 
not to individual variation properly speaking, but to fortuitous circumstances, 
! On p. 855, I am credited with the statement that the eyes of the male of 7’. secedens are uniformly 
bright green. This is an error, since my description of the eyes in life refers to the female (1913, Rev. 
Zool. Afric., II, 3, p. 455). 
