362 Miss G. Ricardo on the Tabaninro 



These probably belong to this genus and form a distinct 

 species ; but the antenn?e being defective, it is impossible to 

 speak witli certainty ; it is the only species of the genus as 

 yet described with brown markings on the wings. 



Stibasoma bicolor, ? , Bigot. 



Two females from Brazil. 



This is a small black species, the first two segments of the 

 abdomen yellow at the sides, the wings hyaline tinged with 

 yellow at the base and on the fore border and with yellow 

 veins. The long tooth on the third joint of the antennae 

 reaches the second ring, which, together with the remaining 

 three, is small and short, the last one ending in a point. 



AcANTHOcERA, Macquart. 



Acanthocera, Macq., Hist. Nat. Dipt. i. p. 209 (18.34) ; Loew, Dipt. 

 Siidat'rik. p. 31 (1860) ; Scbiner, Reise Xovara, p. 95 (1866). 



This genus was not clearly defined by Macquart, who 

 founded it on Hamatopota longicornis, Fabr., which Loew 

 states ]Macquart had never seen, and Schiner believes he had 

 never seen any species belonging to the genus ; he did not 

 clearly distinguish it from Dichelacera, and actually rede- 

 scribed a specimen of Acanthocera longicornis, F., as Diche- 

 lacera loiiyicornis. Schiner gives the shape of the antennae 

 as the chief characteristic, being long and slender, the first 

 joint nearly as long as the third, w hich is divided into nearly 

 equal divisions ; in Dichelacera the lengthened first joint is 

 always shorter than the third. 



Loew considers the true characters of the genus are : — the 

 long, slender, nearly cylindrical body, the depressed head, 

 the face with tubercles, the lengthened first joint of the an- 

 tennae, the great length of the third joint, hairy to the point, 

 with a long tooth at its base, and the unusually great develop- 

 ment of the last four divisions. 



The tooth of the third joint of antennae seems to vary 

 from the long one in A. lonyicornis to a small one in A. ex- 

 stincta and A. coarctuta, if Wiedemann's descriptions are 

 accurate. Schiner's statement that the first joint is nearly 

 as long as the third will not hold good, at least in A. mar- 

 ginalis, "SVlk. ; the first joint is usually about twice the 

 length of the second, but Schiner gives it as four times as 

 long in his description of A. triyonifera. 



The genus may be distinguished by the long, slender 

 antennae, the first joint long, wliich will distinguish it from 

 Dichelacera, but not so long as the third, which is furnished 



