of the Family Tabanidae. 365 



DicHELACERA, Macquart. 



Dichelacera, Macq., Dipt. Exot. i. p. 112 (1838) ; Rondani, Nuovi 

 Aon. 8ci. Nat. Bolopna, (3) ii. p. 192 (I80O) ; id. Archiv. Canestr. 

 iii. p. 78 (1803); Loew, Dipt. Siidafrik. p. 31 (1800); Schiner, 

 Keise Novara, p. 90 (1800). 



This genus was formed by Macquart for the small group 

 divided off from Tabanus, represented by D. cervicornis, 

 damicornis, and T-niyrum, Wiedem., having a long tooth 

 at the base of the third joint of the antennae, all from 

 S. America. In spite of his remark that this character was 

 not distinctive of the genus, many South-American species 

 of Tabanus possessing it (see Dipt. Exot. i. p. ]13), other 

 authors, especially Bigot and Walker, have indiscriminately 

 placed any Tabani from S. America Avith the long tooth to 

 antennas in this genus, ignoring their dissimilarity in other 

 respects to D. cervicornis &c. and their general Tabanus-\\ke 

 appearance. It would seem imperative to restrict to 

 this genus (at least for the present till the South-American 

 Tabani have been thoroughly worked out) the small group of 

 which D. cervicornis is the type ; these are distinguished as 

 rather small flies of a long slender type, with a banded thorax 

 and abdomen, and brown markings on the wings, with a 

 slender third joint of the antennae furnished with a tooth, 

 and usually a rather lengthened first joint ; these character- 

 istics seem as yet all that divide them from Tabanus, though 

 their general appearance and shape will easily distinguish 

 them, as recognized by Loew. 



Schiner distinguishes Dichelacera from Acanthocera by 

 the rather lengthened first joint of the antennae, which, 

 together with the slender shape, he considers is the only safe 

 distinction that divides it from Tabanus ; the first joint being 

 always shorter than the third, which is shaped and ringed as 

 in Tabanus, with a long tooth at the base, will further dis- 

 tinguish it from Acautliocera. 



liestricting the genus as suggested above, all Bigot's 

 species (with the exception of D. longirostris, which is a 

 s|)ecies of Silvius) should be relegated to Tabanus, and will 

 doubtless prove in many instances to be synonyms of previously 

 described species from S. America. Of Walker's species, 

 D. iifacies, niultifascia, and fasciata will belong to Dichela- 

 cera in seusu stricto, the latter being a synonym of D. cervi- 

 cornis ; the remainder of his species will prol)ably prove to 

 belong to Tabanus. Of the Wiedemann species included in 

 Dichelacera, some seem to have been placed there by Walker 

 only, such as D. flava and D. capreoius, which may perhaps 



