96 DIPTERA OF NORTH AMERICA. [PART in. 



Gen. IV. STENOPTERItf A Ma'cq. 



Charact. — Body long and narrow. 



Head almost like that of Dacus ; front of a considerable and equal 

 breadth, somewhat projecting in profile ; face somewhat excavated 

 in profile, perpendicular towards the somewhat upturned anterior 

 edge of the mouth, or but little projecting ; the shallow antennal 

 fovea long and narrow, not distinctly separated from the convex 

 middle portion of the face ; the lateral portions of the face very 

 narrow ; clypeus very large ; eyes large ; cheeks not very broad ; 

 occiput only moderately turgid. 



Antennoz : The first two joints short ; the third narrow and very long, 

 generally reaching a little below the anterior edge of the mouth ; 

 arista apparently bare, or with a pubescence which is so short as 

 to be almost imperceptible. 



Thorax long and narrow ; the transverse suture runs across the whole 

 dorsum in the shape of a shallow depression; viewed laterally, the 

 thorax appears remarkably attenuated towards its anterior end, 

 as the pectus is truncated obliquely in front ; scutellum with four 

 bristles. 



Abdomen remarkably narrow ; the first segment more or less prolonged 

 in the male. 



Feet slender ; the fore coxse very long, inserted remarkably near the 

 collum, and unusually movable at the point of insertion. 



Wings rather narrow ; stigma long and narrow ; small crossvein 

 oblique, inserted more or less beyond the middle of the long discal 

 cell ; second section of the fourth longitudinal vein straight ; pos- 

 terior angle of the anal cell rounded ; the picture of the wings 

 consists chiefly in a dark border of the costa, reaching from the 

 basis of the stigma to the apex of the wing, and in the darker col- 

 oring of the entire anterior basal cell, to which, in most of the 

 species, is added a brown cloud along the posterior crossvein. 



The great uncertainty which seems to have hitherto prevailed 

 concerning the characters of the genus Stenopterina has induced 

 me to enter in more detail about them than about the other 

 genera. If my limitation of this genus be correct, it will con- 

 tain only species closely related in their plastic characters. 

 Their venation alone shows some differences ; some species have 

 the third and fourth longitudinal veins convergent towards their 

 ends, the second longitudinal vein perceptibly shorter, more 

 distant from the costa, and meeting it at. a less acute angle; 

 other species show the opposite of all these characters. As far 

 as I can judge at present, the species of the former group seem 

 to belong principally to the old world. 



