232 A. L. MELANDER. 



hypopygium somewhat swollen. Legs slender, front coxse length- 

 ened, as long as their tibiae, front femora greatly thickened, as long 

 as or but little shorter than their coxae, bristly and spinose beneath ; 

 no tibial spurs, hind tibiae explanate at the tip. Wings long and 

 slender, cuneiform, third vein simple, discal cell long, not acuminate 

 apically, emitting three simple veins to the wing margin, basal cells 

 elongate, the first basal a little longer than the second, second basal 

 and anal cells subequal, anal cross vein perpendicular to the wing 

 margin, anal vein evanescent, anal angle not developed. 



Thorax rufous, with a median dark streak niexicana Wb. et M. 



Thorax yellow, no median darker stripe eloiigata sp. nov. 



Liitanomyia mexicana Wheeler et Melander. 

 Sciodromyin mexicana, Biol. Cent. Am., 1901, Dipt. Suppl., p. 376. 



Female. — Head black, thorax red, abdomen fuscous, legs yellow. Eyes widel-y 

 separated on the front, narrowly on the face, rather small. Face silvery, front 

 grayish. Antennse short, first two joints yellow, third joint pointed, the termi- 

 nal seta less than twice the length of the antenna. Proboscis very short, yellow. 

 Thorax reddish, poUinose, with black macrocha^tfe, and with two abbreviated 

 black vittfB in front. Halteres yellowish. Abdomen cylindrical, blunt. Legs 

 lengthened, slender, except the thickened anterior femora; posterior tibise with 

 a slight widening at extreme tip ; anterior coxse elongate, yellow, remaining coxae 

 reddish. Wings grayish hyaline, narrow, somewhat pointed, veins fuscous. 2 mm. 



Guerrero, Mexico. 



"-' liitanoniyia elongata sp. nov. 

 Quite similar to L. mexicana. It differs, however, by its lighter color and more 

 slender form. The thorax is decidedly narrowed in front, whereas in mexicana 

 it is rather square. The abdomen is fuscous in but a single specimen, all the 

 others have the abdomen yellow. There is sometimes a fuscous spot present on 

 the dorsum of the sixth abdominal segment. Moreover, the body is much less 

 pruinose, the hind tibife lack the terminal swelling, there is no trace of the me- 

 dian thoracic dark stripe, the third antennal joint is rather smaller, the coxse are 

 concolorous with the legs, the wings are rounded at tip, and generally the costa 

 JC vaguely parallel with the hind margin. The sides of the face are parallel ; in 



/ mexicana the face is narrower centrally than above or below. The antennae vary 



in color from wholly yellow to the third joint black. The thorax is sometimes 

 even lighter medially. 



Sixteen specimens; Mass., Wis., S. Dak. 



The Massachusetts specimens are slightly lighter in color than 

 the more western ones. 



OREOTHALIA gen. nov. 

 Slender black species of the habitus of Cliuocera. Head oval, 

 vertical ; eyes widely separated, emarginate at the antennae, extend- 



