150 DIPTERA OF NORTH AMERICA. 



North American species of the genera Hydrellia and Phihjgria 

 only are known to me. 



Gen. I. HYDRELLIA R. Desv. 



The species of Hydrellia are very easily recognized by the very 

 short but exceedingly close pubescence of the eyes, and by the 

 pectinations of the antennal bristle. The other characters are : 

 Second joint of the antennae not unguiculated ; face rather narrow 

 and perpendicular, slightly convex, receding a little towards the 

 border of the mouth ; opening of the mouth not widened ; cheeks 

 descending very little beneath the eyes. Legs rather slender; 

 middle tibiae on their upper side without bristles ; costal vein ex- 

 tending to the tip of the fourth longitudinal vein. 



Synopsis of the Species.* 

 , / Anterior coxse yellow. 1 ischiaca, n. sp. 



I Anterior coxse blackish. 2 



2 ( Face snowy white. 2 hypoleuca, n. sp. 



I Face not white. 3 



o ( Face brownish-black, opaque. 3 obscuripes, n. sp. 



I Face yellow. - 4 



{Face dark yellow, narrow, much dilated below. 4 scapularis, n. sp. 

 Face pale yellow, rather broad, but little widened below. 

 5 valida, n. sp. 



1. H. ischiaca Loew. 9- — Subsenescenti-fusca. antennis nigris, facie 

 punctoque frontali albis, thoracis margine antico pleurisque canis, pedi- 

 bus ex fusco nigris, coxis anticis, genibus, tibiarum apice tarsorurnque 

 basi ex rufo fiavis. 



Somewhat brassy brown, antenuse black, face and frontal dot white ; ante- 

 rior border of the thorax and pleurae whitish-gray, legs brownish-black, 

 anterior coxse, knees, tips of the tibiae and base of the tarsi reddish- 

 yellow. Long. corp. 0.1. Long. al. 0.11. 



Face of medium breadth, slightly dilated below, without keel ; 

 the ground color in the middle is more pronounced, giving it rather 

 a brownish aspect ; on each side of the face there are four little 

 bristles, one above the other. Palpi yellow, cheeks a little de- 

 scending. Antennae entirely black ; the bristle in the described 

 specimen has seven rays. Front proportionately broad, dusted 

 with brown; the dot immediately above the antenna? white. Upper 



* The species No. 6 has not been included in this synopsis.— 0. S. 



