NORTH AMERICAN DIPTEHA. 155 



4. — Front tibise ending in a spine-like process Bihio. 



Front tibife terminated with a coronoid spiny process Dilo|>liU»i. 



5. — Front tibise terminating in a spinons process ANpiNtes. 



Front tibiae of usual form; third vein not furcate Scatopse. 



Family SIMULIDiE. 

 One genus Siinuliuni. 



Family BLEPHAROCERID^. 



1. — An incomplete vein present near the posterior wing margin 2. 



No incomplete vein near posterior margin.. PaltOMfoina. 



2. — Second vein with two branches 3. 



Second vein simple 4. 



3. — Origin of anterior branch of second vein coincident with origin of third 



vein; anterior tibiae curved in % Bibioeepliala. 



Origin of anterior branch of second vein beyond origin of third vein ; ante- 

 rior tibiffi straight in % .4 gat lion. 



4. — Eyes contiguous, bisected by an infacetted cross-band, or by a simple groove. 



Blepharocera. 

 Eyes widely separated, not so bisected Lipoiieura. 



Family RHYPHID^. 



Second vein reaching costa at same point with first; eyes separated by a broad 

 front, occiput little developed Olbiogaster. 



Second and first veins terminating separately in costa; front narrower, occiput 

 much developed Rhyphus. 



Family ORPHXEPHILID.E. 

 One genus Orphiiephila. 



NOTES. 



MyoetophiliDtE : — I cannot with certainty separate the genus 

 Diomonus Wlk. (List, i, 87) from Boletina by means of the descrip- 

 tion of that author. By taking his statement as true that Diomonus 

 has the wings of Leptomorphus, I have inserted it in the table, as 

 distinguished from Boletina by the costal vein extending but little 

 beyond the termination of the third vein. But I cannot rely on 

 any interpretation of the indefinite statement that " the areola under 

 the anterior margin of the wing, absent in that genus [Leptomor- 

 phis], is present in this [Diomonns].^^ I would omit the genus alto- 

 gether, but for the fact tliat it is indicated in the Osten Sacken Cata- 



TRANS. AM. ENT. SOC. XIX. JUNE, 1892. 



