264 Mr. E. E. Austen on 



species, the members of vliicli resemble one anotlier so 

 closely that extreme care is necessary for their discrimination. 

 Lastly, it cannot be too strongly impressed upon all writers 

 on Tabanidse that in a oenus like Tahanus (in which plastic 

 differences between species are seldom obvious, while, on the 

 other hand, the number of described species already amounts 

 to considerably more than nine hundred) descriptions, if they 

 are to admit of correct interpretation, must be comparative 

 {i. e. must include a reference to allied species, and clearly 

 indicate the points in which the supposed new species ditfers 

 from them), and should always, if possible, be accompanied" 

 ])y a figure carefully drawn by a competent artist. Photo- 

 graphic illustrations are seldom satisfactory, since the 

 imperfections of the particular specimen figured, which are 

 reproduced only too faithfully, frequently obliterate many 

 of the si)ecific characters. 



The British Museum (Natural History) is much indebted 

 to Mr. Taylor for the generous gift of paratypes of all the 

 species of Tabanus described by him in his paper as new, as 

 well as exami)les of all but one of those re-describcd by him 

 under previously existing names, and the study of these 

 specimens has gVeatly facilitated the preparation of the sub- 

 joined notes. 



"Tabanus abstersus, Walker" (p. GO, jd. xiv. fig. 14)*.— 

 Tuhnnus abstersus, Walk. (Ins. Saund., Dipt. pt. i. p. 58, 

 1850), = r. circumdatus^WaW. (List Dipt. Ins. in Coll. Brit. 

 Mus., i. p. 185, 184-8). ^Mr. Taylor's figure, which shows an 

 insect in which the majority of the veins in the distal half of 

 the wings are strongly infuscated over the greater jjortion of 

 their ex\ent, has nothing to do with Tabanus circiimdalus, 

 Walk. (syn. T. abstersus, Walk.), in which the wings are 

 hyaline and tiie vcnis are not infuscated, but looks like 

 f. limbalinevris, Mac(|. (Dipt. Exot., Suppl. iv. p. 29 (1850), 

 nee T. limhatinevris, iMaoq., op. cit. Suppl. ii. p. 16, 1817). 

 The ? specimen forwarded by Mr. Taylor, however, as an 

 example of the species regarded by him as Tabanus abstersus, 

 Walk., belongs neither to 7'. circumdatus, Walk., nor to 

 T. Ihnljutinevns, Macq. (1850), but to a species unknown to 

 the present writer. In the specimen sent the angle on the 

 upper nuirgin of tiie expanded portion of the third joint of 

 the antenme is produced into a long thumb-like process, 

 much as in Rhinouii/za, while the ground-colour of the 

 dorsum of the abdomen (with the e\cepti(m of the lateral 



* Tli(,' (h'tiiiN in br.iclcets refrr t<. Mr. Tiiylor's imptM'. 



