144 inse;cutor insciti^ menstruus 



Ormosia serridens, new species. 



Closest to O. meigenii (O. S.) ; gonapophyses of the male 

 hypopygium minutely serrate. 



Male. — Length, 3.8-4 mm. ; wing, 4.5-4.8 mm. 



Similar to O. meigenii in most respects. Average size 

 smaller ; male hypopygium conspicuously different in structure. 

 The inner pleural appendage has a long lateral bill-like point 

 so the appendage appears somewhat like the head of a bird. 

 Lateral gonapophyses broad, of nearly equal width throughout, 

 the apex obliquely truncated and with about a dozen minute 

 teeth in addition to the small apical point. Inner apophyses 

 slender, slightly curved, the outer margin minutely serrulate, 

 the teeth decreasing in size from the base outwardly, apical 

 point small. 



Habitat. — Maryland, Virginia. 



Holotype, $ , Great Falls, Virginia, April 20, 1916 (W. L. 

 McAtee). 



Paratopotype, $ ; paratype. $ , Cabin John Bridge, Mary- 

 land, April 11, 1915 (R. C. Shannon), $, April 13, 1916 

 (W. L. McAtee). 



Type in the United States Biological Survey collection. 



Ormosia dentifera, new species. 



Coloration gray ; wings with a faint grayish tinge ; cell ist M., 

 open, anal veins nearly divergent ; gonapophyses of the male 

 hypopygium produced into powerful curved horns. 



Male. — Length about 3.8 mm. ; wing, 4.3 mm. 



Female. — Length about 3.8-4 mm. ; wing, 4.6 mm. 



Antennas moderately elongated, the scape brown, the flagel- 

 lar segments in the male elongate-oval, black, with a conspicu- 

 ous white pubescence ; in the female, the flagellar segments 

 are oval. Head gray. 



Pronotum brownish gray, the lateral margins dull yellow, 

 Mesnonotum gray without distinct stripes. Pleura gray. 

 Halteres rather long, pale yellow, the knobs a little darker. 

 Legs with the coxse, trochanters, and bases of the femora dull 

 yellow, remainder of the legs dark brown. Wings with a faint 

 grayish tinge, the stigma darker, brownish ; veins brown. 



