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species in which the face is conically produced, although the facial 

 prolongation does not serve to accommodate the basal portion of 

 the proboscis when retracted. Lutz considers that the possession 

 of a very long protrusible proboscis points to a liquid diet other 

 than blood, and from his own observations he doubts whether 

 species in which such an organ exists bite and suck blood on the wing. 

 As is mentioned below in the notes on Pangonia angulata, Fabr., and 

 P. gulosa, Wied. (pp. 61, 62), according to Westermann, P. rostrata, 

 Linn., in which the proboscis attains so remarkable a length, is 

 one of the species most troublesome to domestic animals at the 

 Cape, though owing to the length of the proboscis, it can only bite 

 when on the wing. It is significant, however, that Westermann 

 adds : " Nevertheless this Pangonia appears to prefer to suck 

 the nectar of flowers rather than blood, since I frequently found 

 it on the blossoms of different species of Pelargonium : other kinds 

 of Pangonia, on the contrary, I never met with on plants." In 

 species such as P. rostrata and P. gulosa, the proboscis when fully 

 or even partially extended greatly exceeds the piercing stilets in 

 length, and this in itself would obviously offer a mechanical 

 obstacle to the piercing of the skin of a mammal by these flies ; it is 

 possible that when such flies appear to be attacking animals they 

 are merely sucking up the blood flowing from wounds caused by 

 other Tabanidae, and this suggestion may perhaps afford the 

 explanation of Westermann's remark that, whenever he observed 

 P. rostrata round domestic animals, the latter " were in many places 

 quite red owing to the blood that streamed from the wounds caused 

 by the flies." Whatever be the case, however, with regard to 

 species in which the proboscis is exceptionally long, it would appear 

 that others, at any rate occasionally, bite and suck blood on the 

 wing. Thus, a specimen of the new species near P. ruppdlii, Jaenn., 

 already alluded to, from South Bornu, Northern Nigeria, September, 

 1907 (Dr. H. A. Foy), bears the label : " Attacking horse ; sucked 

 blood on the wing without settling, and darted away after feeding." 

 The females of the majority of species of Pangonia are extremely 

 blood-thirsty, and, while sometimes molesting human beings, are 

 especial pests of domestic animals, which they often attack in large 



