234 



LEPTID^ 



the Xylophagince and the Co&noinyince, and the only Stratiomyidm with 

 spurred tibise are the Xylomyinm and a few exotic (but one European) 

 Berinm ; the Berince may be also distinguished from the Lcpfidce by the 

 short pnefurca, and consequently the only difficulty for the British student 

 lies between Xylomyia and Xylophagus ; the complete though faint 

 ambient vein distinguishes Xylophagus, while the closed fourth posterior 

 cell conveniently though empirically distinguishes Xylomyia. The 

 gigantic exotic Acanthomeridce are distinguished by the entire absence 



Fig. 162. — Rhyphus punctatus <J . x 10. 



of tibial spurs, and by a quite distinct venation in which the fourth 

 posterior cell is bluntly closed in a different manner from any others of 

 the EREMOCHiETA. The Tabanidce may be distinguished at once by their 

 large thoracal squamse, though an affinity exists in the presence of "touch- 

 hairs " beneath the front tarsi. An entirely misleading resemblance exists 

 between the venation of Leptis (fig. 162) and Rhyphus (fig. 163), but the 



Fio. 163.— Lepiis scolopacea S. x 8. 



simple cubital vein and the widening anal cell of Rhyphus are quite 

 distinct from any venation among the Brachycera. 



The Leptidm (including the old families of Xylophagidoc and Ccenomyidcc) 

 are composed of about three hundred species from all parts of the world, 

 though very few have been described from Africa. About ninety species are 

 Palsearctic, and we now admit nineteen as British (of which two are probably 

 only varieties), though seven or eight others have in time past been 

 reputed as British, and of these we may expect to find three or four. 

 They usually occur in woodland districts or amongst shrubs and herbage 

 in marshy places, while some species of Leptis rest head downwards on the 

 stems of trees and sometimes have a disconcerting habit of suddenly darting 

 at an observer ; some species are said to be predaceous upon other insects, and 

 some are said to be blood-suckers and to be capable of inflicting a severe 

 bite on man, but I have never personally known of such a case ; there 



