350 TABANID.E 



According to the probable derivation of the name of this genus the 

 second " a " should be pronounced long = Tabdnus. 



Synonymy. — Linne founded this genus in the 10th edition of the Sy sterna Naturae 

 in 1758, but naturally his genus was of a rather comprehensive nature ; he included 

 twelve species of which six were European, one being a Ilcematopota and one a 

 Chrysops but the other four belonging to the present comprehensive genus, T, 

 hovimis has always been correctly accepted as the type species. 



Tahle of Subgenera. 



1 (4) Eyes pubescent. 



2 (3) Ocelligerous tubercle more or less distinct. Upper branch of the 



cubital fork simple. Thepjoplectes. 



3 (2) Ocelligerous tubercle absolutely absent. Upper branch of the 



cubital fork usually with a recurrent veinlet (fig. 215). 



Atylotus. 



4 (1) Eyes bare. Ocelligerous tubercle absent. Tabanus 



(sensu stricto). 



THEEIOPLECTES. 



(Subgenus of Tahanus). 



Therioplectcs Zeller, Isis, 1842, p. 819. 



" Eyes pubescent, with three or four purple cross-bands and interven- 

 " ing green intervals ; ocelligerous tubercle more or less distinct ; head of 

 " the male not differing much in size or shape from that of the female ; 

 " the difference in size between the large and small facets on the eyes of 

 " the male is but very moderate, and the dividing line between them 

 " indistinct." 



The above quoted words are those used by Osten Sacken in his last 

 definition of this subgenus (Western Diptera, 215, 1877), and are only a 

 slight modification of characters previously given by him when founding 

 the subgenus Atylotus. 



Zeller when founding Therioplcctes gave no character beyond "mit 

 " behaarteu Augen in beyden Geschlechtern," but he separated T. fulvus 

 Mg., T. rusticus Eabr., and T.plchcjus Fall, into a " Zweyte Unterabtheilung," 

 and consequently when Osten Sacken found a character common to these 

 three species which was not shared with the majority of the hairy-eyed 

 Tabani he was justified in giving a new subgeneric name {Atylotus) to 

 them, even though it subsequently became considered that the first 

 species of Zeller's "Erste Unterabtheilung," T. tricolor Zell., was also 

 an Atylotus; furthermore it is by no means certain that Osten Sacken 

 intended his subgenus Atylotus to include such species as T. tricolor 

 Zell. 



Osten Sacken's characti;r derived from the comparison between the 

 large and small facets on the eyes of the male does not hold good in 

 regard to all European species, as in some species the facets are very 

 different in size and rather abruptly contrasted by a dividing line. 



Therioplcctes is easily distinguished from Tabanus by its hairy eyes in 

 both sexes, even though microscopic examination may often detect hairs 



