10 PROCEEDINGS OF THE NATIONAL. MUSEUM. vol.65 



2. Prescutellar acrostichals absent; tibiae and metatarsi of fore legs black, 

 apical four tarsal segments white; wings largely infuscated; scutellum 



not velvety black manuleata (Loew). 



Prescutellar acrostichals present ; tibiae and tarsi of fore legs white ; wings 



yellowish; scutellum largely velvety black femoralis (Loew). 



.*$. Median dorsal vitta of thorax continued to posterior margin, not attenuated 

 posteriorly ; orbits entirely gray pruinescent ; wings but little darkened at 



bases; stout species opaca (Loew). 



Median dorsal vitta of thorax not continued to posterior margin, or if so 

 only as a slender line ; orbits only gray pruinescent round bases of bristles ; 

 wings fuscous at bases; slender species trivittata (Loew). 



LIST OF SPECIES OF THE DISTRICT OF COLUMBIA REGION. 



L. femoralis Loew. — Spring Hill, Virginia, August 26, 1922, H. L, 

 Viereck: Falls Church, Virginia, June 26, July 5, August 24, Sep- 

 tember 17; High Island. Maryand, July 8, N. Banks; Glen Echo, 

 Maryland, August 3. 6, 1922, L. L. Buchanan: July 30. August 2, 

 1922, Malloch. 



L. tHmttata Loew, — Has been collected several times in the Pied- 

 mont area, at dates ranging from June 14 to August 22 ; taken twice 

 on flowers of Ceanothiis ajnericanus. P. I. 



Genus PHYSOGENIA Macquart. 



We have seen but one species from America, vittata Macquart, 

 represented in material from Cuba, Brazil, and Nicaragua- 

 Genus PACHYCERINA Macquart. 



We have seen only one species of this genus from America, rep- 

 resented by specimens from Florida and Nicaragua. These were 

 named favida Wiedemann, by Coquillett, and probably are the same 

 species as ornata Melander, described from Mexico, synonymy we 

 venture even though Wiedemann's description of the thoracic colora- 

 tion does not agree exactly with that of the specimens above re- 

 ferred to. 



Genus CAMPTOPROSOPELLA HendeL 



Two species of this genus occur in our region which may be 

 separated by the characters cited below. 



KET TO SPECIES. 



L Wings hyaline, immaculate 2 



Wings fuscous or marked with fuscous 3 



2. Fore legs not darker than mid and hind pairs ; arista loosely long plumose, 



vulgaris Fitch. 



Fore legs distinctly darker than mid and hind pairs, the tarsi and apices of 



tibiae subfuscous ; arista with shorter and more dense plumosity ; hypopy- 



gium as in Figure 17__^ verticalis Loew. 



