198 DIPTERA OF NORTH AMERICA. [PART II. 



towards the front, so as to end rather far from the tip of the wing 

 in the vicinity of the third longitudinal vein. 



Hah. Cuba. (Riehl.) 



Observation. — This species is also found in Brazil. 



Gen. XXXV. LIAtfCAtUS. 



The genus Liancalus shows the closest relationship to the 

 genera Scellus and Hydrophorus. It agrees with them in the 

 following characters : The body in general is beset with neither 

 numerous nor long bristles. Wings elongated ; the posterior 

 transverse vein very closely approximated to the margin of the 

 wing ; feet elongated and slender ; the first joint of the hind tarsi 

 on the upper side without bristles, not shorter than the second, 

 but in the majority of the species, longer. Face in both sexes 

 broad, provided with a small tubercle upon the lowest third of 

 each side of the orbit, and with an indistinct swelling running from 

 one tubercle to the other. Antennas rather short, the first joint 

 without hairs ; the apparently bare arista dorsal, distinctly two- 

 jointed. The hypopygium of the male imbedded. 



The above mentioned three genera differ sufficiently from the 

 other genera of the Dolichopodidse by the above stated characters, 

 which they have in common. The genus Liancalus in particular, 

 however, differs from Scellus and Hydrophorus in the following 

 points : 1. All the femora are slender and unarmed, while the 

 genera of Scellus and Hydrop>horus have the femora very much 

 thickened toward the basis, which at least in the males, is armed 

 on the under side ; 2. The segments of the abdomen are beset 

 with bristles before the posterior margin, which is not the case 

 in the species of Scellus and of Hydrophorus. 



The genus Liancalus contains as yet only three European and 

 one North American species. They form two groups ; in the first 

 the scutellum has only four bristles and the exterior appendages 

 of the hypopygium are more lamelliform, while in the second the 

 scutellum has six bristles and the exterior appendages of the 

 hypopygium are filiform. To the first group belongs Liancalus 

 lacustris Scop, and leucostomus Loew, to the second L. virens 

 Scop, and the following North American species. 



The name of the genus (from uios, smooth, and ayxd^, arm) 



