164 



thorax is some shade of brown (yellowish-, reddish-, or clove-brown), 

 and in Hippobosca (see Plate XIII.) the thorax is conspicuously 

 mottled with yellow. The eyes are widely separated in both sexes ; 

 the antennse, which are inserted in pits or depressions near the 

 margin of the buccal cavity, are invisible from above in Hippobosca, 

 but in genera the species of which are parasitic on birds they are 

 large, prominent and scale-like, and bear long hair. In all 

 Hippoboscidae the palpi are in the form of a pair of rigid chitinous 

 lobes or narrower processes, which project downwards or forwards, 

 and constitute a partial sheath or protection for the proboscis. 

 The latter, which is composed of the same parts as that of the blood- 

 sucking Muscidse, is curved, extremely slender, and protrusible, 

 being entirely withdrawn from view when not in use. In 

 appearance it presents a decided resemblance to the proboscis of 

 the Tsetse-flies, and it also acts in a similar manner, its tip being 

 armed with sharp chitinous teeth which enable the organ to pierce 

 the skin of the host.* 



Leaving the genera Lipoptena and E chesty pus out of the question, 

 the wings in all species at present known to occur in the Ethiopian 

 Region are long, generally more or less infuscated, and have the 

 principal veins approximated to the costal (anterior) border; the wings 

 of species belonging to the genera Olfersia, Pseudolfersia, Lynchia, 

 Ornithoica, and Ornithomyia, which are parasitic on birds, exhibit 

 in addition less strongly developed veins running obliquely across 

 the surface. 



The genus Lipoptena is represented in Africa by L. chalcomelcena, 

 Speiser, which is parasitic upon ibex in the Anglo-Egyptian Sudan 

 and Egypt, and by the European L. cervi, Linn., which besides 

 occurring in Algeria and Egypt, appears to have been introduced 

 into South Africa with remounts during the Boer War ; in this 

 genus the wings are shed by the female almost invariably, and by 

 the male frequently, on reaching a suitable host, and like Melophagus 

 ovinus, Linn, (commonly known in England as the " Sheep Tick "), 

 which is entirely apterous, specimens of Lipoptena which have shed 



* For an account of the structure and mode of action of the proboscis, c/. F. H. 

 Miiggenburg, " Der Riissel der Diptera pupipara " : Archiv f/ir Naturgeschichte, 

 58 Jahrg., I. Bd., pp. 287-332, Taf. XV., XVI. (1892). 



