134 Journal New York Entomological Society, ^'o'- >^>^^'^, 



(concolorous with the rest of the head in buteonis), and the reddish- 

 brown mesonotum with three yellowish lines (fuscous brown without 

 markings in bittcoiiis). From O. fusciventris Wiedemann, described 

 from Kentucky, buteonis differs in larger size {fusciventris is only 

 5 mm. long) somewhat less deeply emarginate anterior border of 

 clypeus (deeply and angularly emarginate in fusciz'entris) , fllattish 

 scutellum (basally inflated in fusciventris) and in the coloration of 

 the thorax being much darker than the head (concolorous in fusci~ 

 veiitris). 0. pilosnla Van der Wulp, froin Costa Rica, is smaller 

 (5.5 mm.) and has the head and thorax rufous. O. haiticnsis Ron- 

 dani, from Haiti, is distinct in its dark-haired antennae and different 

 venation, the first longitudinal vein ending in the costa before the 

 first crossvein. This latter venational character will also separate 

 O. avicularia Linnaeus, the common European species, and O. varipcs 

 Walker, of Mexico to Colombia and Peru, the latter further differ- 

 ing in the shape of the antennary process. O. anchincuria Speiser 

 (;=0. pallida Say) may be distinguished at once by the interstitial 

 first and second cross veins, making the second basal cell nearly as 

 long as the first basal cell (much shorter in buteonis). The colora- 

 tion is entirely different from O. butalis Coquillett, described from 

 Bering Island. 



9. Ornithomyia costaricensis new species. 



Length 7 mm. Front and vertex wholly glossy bright ferruginous, the 

 posteriorly broadening orbital margins and the vertex triangle perfectly 

 smooth and polished, the median area microscopically tesselated, giving it 

 a satiny luster, and of subuniform width. Clypeus concolorous with front 

 and vertex, anteriorly medially emarginate because of a deep rectangular pit, 

 posteriorly also with a large, deep, oval pit. Antennary processes twice as 

 long as broad, their sides convex and their tips narrowly rounded, of a darker 

 ferruginous color than the clypeus and front and provided with long, fer- 

 ruginous hairs. Eyes glossy black. Humeral prominences pale, heavily black- 

 haired. Mesonotum shining blackish, slightly suffused with reddish along the 

 anterior sutures, bearing a faintly impressed median line and deep, slightly 

 curved, transverso-median depressions on each side of it. Scutellum rounded 

 posteriorly, medially much depressed transversely and this depression bearing 

 several long-black hairs, shining black like the mesonotum but with the 

 anterior margin reddish testaceous, interrupted medially by a blackish stain. 

 Sternum and under side of head greenish testaceous. Legs beneath greenish 

 testaceous, above fusco-testaceous, becoming dusky on the tibiae, fuscous on 

 the tarsi and with the claws black. Abdominal tegument dark brown, but so 

 heavily clothed with black hairs as to appear blackish. Wings slightly clouded, 



