AMERICAN DIPTERA. 



289 



yellow ; apices of tibiae brownish ; femora moderately stout ; post-tibiae 

 strongly arcuate, spines weak ; inner surface of post-femora polished. 

 Wings decidedly brownish tinged; stigma colored. Length 4.4 mm. ; 

 wings, 5.0 mm. 



9 . Similar, especially to those placed under nigripes Lw., differ- 

 ing mainly in the apex of first abdominal segment being cinereous, 

 not white, and much broader and interrupted medianly. The speci- 

 men examined is somewhat soiled, and the apices of following seg- 

 ments are not gray, but in certain aspects one can perceive faint in- 

 dications of interrupted apical bands ; the ovipositor is very long and 

 slender (Fig. 48), gradually tapering from its elongate base; wings 

 hyaline, stigma shorter than fourth section ; ultimate section of fourth 

 vein strongly sinuate. 



Type.—&. Mt. Tom, Mass., July 14, 1905, Fig. 47, John- 

 son, B. S. N. H.). 



Para types.— Chain Bridge, Va. (l o 71 , Fig. 181, coll. Banks), 

 Hanover, N. H. (1 9 , Fig. 48, Johnson, B. S. N.H.). Taken 

 in June and July. 



This species may be separated from nigripes Lw., as here 

 represented, by the silvery front and face, interrupted gray 

 abdominal fasciae and brownish wings of o 71 , while the 9 is 

 only distinguished by the absence of the pure white narrow 

 band of first abdominal segment. It is a question whether 

 this female specimen is distinct from that species. 



10. P. caudatus n. sp. 



d 1 . Front and face sericeous, with yellowish tinge ; occiput brown- 

 ish-gray. Antennas black, abruptly acuminate (Fig. 15). Thorax 

 subopake, brownish tinged ; pleurae, especially metanotum cinereous 

 tinged. Humeri and halteres black. Scutellum more shining. Abdo- 

 men nearly shining, brownish tinged ; first, interrupted medianly, lateral 

 angles and ventral margins of following segments weakly cinereous ; 

 fifth longer than fourth. Hypopygium nearly shining, terminal lobe 

 very large (Figs. 60-61), as broad as, and about twice as long as fifth 

 segment, quadrate, flattened apically by the large cleft ; intermediate 

 lobe just visible ; ventral lobe black. Legs black, with trochanters, 

 extreme apices of femora, and tarsi basally, yellow ; tibiae brownish, 

 with dark median rings. Inner surfaces of post-femora polished; 

 spines rather strong. Wings (Fig. 140) grayish ; with stigma colored. 

 Length, 3.5 mm. ; wings, 3.8 mm. 



Type. — Sea Cliff, Long Island, 5-10 Sept. {coll. Banks). 

 The abdomen is somewhat shrunken longitudinally, and is 

 probably a little longer than given. The species is rather 



TRANS. AM. ENT. SOC, XXXVI. (37) DECEMBER, 1910. 



