502 Mr. F. W. Edwards on Three new Species oj 



LXI. — Three new Species of the Dipterous Genus Olbio- 

 gastev, O.-S., in the British Museum Collection. By 

 F. W. Edwards, B.A., F.E.S. 



(Published by permission of the Trustees of the British Museum.) 



The genus Olbiogaster was founded by Osten-Sacken in 1886 

 (Biologia Central!- Americana, Diptera, vol. i. p. 20) for an 

 insect belonging to the family Rhyphidse, of which he had 

 seen specimens from Costa Rica and Porto Rico; at the 

 same time he referred to the new genus Bellardi's Rhyphus 

 tceniatus, described from Mexico. Townsend (Ann. & Mag. 

 Nat. Hist. ser. 6, xx. p. 21, 1897) recorded another specimen 

 of 0. tceniatus from Mexico ; Williston in 1901 (Biologia 

 Centr.-Amer., Dipt. vol. i. Suppl. p. 229, and pi. iv. fig. 6) 

 described and figured another Mexican specimen ; and, finally, 

 Enderlein in 1910 (Stett. ent. Zeit. vol. lxxi. p. 65) described 

 another species from South Brazil. 



It will thus be seen that the very few known specimens of 

 this interesting genus were all obtained in the Neotropical 

 region. The British Museum contains examples of two 

 additional species from West Africa and Ceylon, and, as these 

 specimens so greatly extend our knowledge of the geo- 

 irrajihical ranee of the genus, it seems worth while to describe 

 them. At the same time it may be desirable to give a name 

 to the specimen figured by Williston and to call attention to 

 some inaccuracies in his depiction of the wing-venation. 



1. Olbiogaster sackeni, sp. n. (Williston MS.) 



This name is proposed for the above-mentioned specimen 

 figured by Williston, who refrained from naming it himself 

 as he was unable to compare it with the description of 

 0. twniatus, Bellardi. According to this latter description 

 there is a very marked difference in the coloration of the legs 

 in the two specimens, and, while it is indeed possible that 

 they represent merely varieties of one species, it will, in view 

 of this difference, be convenient to refer to Williston's 

 specimen under a separate name. The distinction is as 

 follows : — 



O. tceniatus, Bell. Legs black, the apex (parte antica) of 

 the front femora, the front tibias, the base of the middle and 

 hind tibise, and the apex of the hind femora yellow. 



0. sackeni, sp. n. Legs yellow, the base of the four 

 anterior femora, the whole of the hind femora, the extreme 



