160 



Genus LYPEROSIA, Rondani. 



Dipterologise Italicse Prodromus, Vol. I., p. 93 (1856), and Vol. V., 



p. 230 (1862). 



PLATE XIII., FIG. 103. 



The genus Lyperosia is distinguished from Stomoxys by the palpi 

 being broader, more or less flattened from side to side, and as long 

 or almost as long as the proboscis, instead of filiform, not more than 

 half as long as the proboscis or considerably shorter even than this, 

 and not or scarcely projecting beyond the anterior margin of the 

 buccal cavity. When the insect is not engaged in feeding, the 

 palpi are closely applied to the proboscis and conceal it, as in the 

 case of Glossina, palpi and proboscis together looking like a relatively 

 rather stout horizontal process in front of the head ; it should be 

 noted, however, that in dead specimens the proboscis almost 

 invariably droops more or less, and may even assume a vertical 

 position. The species of Lyperosia, which are few in number, are 

 the smallest of blood-sucking Muscidae, and none of the six or seven* 

 African species at present known exceeds 4 mm. in length. The 

 coloration of the body is dull and inconspicuous, grey, olivaceous- 

 grey, or brownish, with darker longitudinal markings on the 

 thorax ; L. punctigera, Austen (Plate XIII., fig. 103), is characterised 

 in addition by the presence of dark spots on the abdomen. The 

 eyes are narrowly separated above in the male, but are wider apart 

 in the female ; the wings are hyaline or slightly brownish. 



These little flies often swarm on domestic animals (horses, cattle, 

 and camels), and sometimes also attack human beings. f The 

 European L. irritans, Linn., which has been introduced into the 

 United States of America, is there known as the " Horn-fly," owing 

 to its habit of clustering in a dense mass or ring about the base and 

 on the concave side of the horns of cattle. 



* Lyperosia longipalpia, Roubaud (Comptes Rendua Hebdomadairea des Seances 

 de la Societe de Biologie, 1906, p. 896, fig. 2 Senegal) is very possibly a synonym of 

 L. minuta, Bezzi. 



f See below, p. 162. 



