June, i9i6.] SwENK : NoRTH AMERICAN HiPPOBOSCID.E. 135 



the costal veins and bases of the longitudinal veins blackish, the first longi- 

 tudinal vein ending in the costa slightly before the first crossvein, the costal 

 border of the marginal cell fully twice as long as the costal border of the 

 first submarginal cell, and the first basal cell twice the length of the second 

 crossvein longer than the second basal cell. 



Type. — Juan Viiias, Costa Rica, March, 1902, by L. Bruner. 



The shiny blackish mesonotum seems to distinguish this species 

 from all of the described North American congeners except O. hutalis 

 Coquillet, which is much smaller (4 mm.), has the front black spotted 

 on the orbits and vertex with yellow, and is otherwise very different. 

 The species is really close to O. erythrocephala, but apparently differs 

 in the deep anterior pit on the clypeus, the red anterior border on 

 the scutellum, and, compared with Van der Wulp's description of 

 O. robust a which Austen places as a synonym of erythrocephala after 

 a comparison of the types of both in the British Museum, it should 

 also differ in darker legs and abdomen, although these color dif- 

 ferences are not clear from a comparison with Leach's original de- 

 scription of crytliroccphahj. From O. haiticnsis it differs at once in 

 the ferruginous hairs on the antennary process, the dark legs and 

 the different venation (the first longitudinal vein ends considerably 

 before the first crossvein and the costal border of the marginal cell 

 is less than twice as long as the costal border of the first submarginal 

 cell in haitiensis). The venational characters are much like those 

 of O. butconis, just described, and separate the species from several 

 of its congeners. 



10. Ornithomyia pirang^ new species. 



Length 4.5 mm. Head and thorax above shining brownish testaceous, 

 clearing to yellowish testaceous on the lower orbital margins, vertex, anterior 

 margin and median line of mesonotum and base of scutellum. Orbital mar- 

 gins, broadening posteriorly, and vertex, polished, the median area conspic- 

 uously duller and of subuniform width throughout. Clypeus anteriorly medi- 

 ally emarginate and bearing a small, shallowly rounded pit, most of its dorsal 

 surface involved in a large, oval, deep pit. Antennary processes a little less 

 than twice as long as broad, the outer margins strongly convex and the inner 

 margins nearly straight, causing the pointed tips to appear divergent, in color 

 fusco-testaceous and clothed with dark hairs. Eyes brown. Mesonotum with 

 a slight median longitudinal depression and somewhat stronger transverse, 

 slightly sinuate, median lateral depressions. Scutellum slightly convex and 

 with a slight transverse depressed line near apex which bears four strong 

 black bristles. Under side of head and thorax shining pale testaceous, the 



