260 NORTH AMERICAN DIPTERA. 



3. First posterior cell with a stump of vein from the third longi- 



tudinal vein: 



Sphyximorpha, 4, n. Mixogaster, 4, 9. 



Microdon, 4, 8, (fig. i). Rhopalosyrphus, 4, 8, 9, 10. 



4. Antennae elongate: 



Sphyximorpha, 3, II, (fig. 24). Pipiza, 8. 



Chrysogaster, spp. (fig. 3). Platynochaetns, 2. 

 Chrysotoxum, 2, 8, (fig. 4). (Phalacromyia), 5. 



Copestylum, I, 5, 9, (fig. 14). Rhopalosyrphus, 3, 8, 9, 10. 



Lepidostola, Rhysops. 



Megametapon, 5, 10. Sphecomyia, sp. 



Microdon, 3, 8. Spilomyia spp. 7. (fig. 23). 



Mixogaster, 3, 9. Volucella, i, 5, 8. 

 Paragus, spp. 8. 



5. Arista plumose: 



Arctophila, 2. Megametapon, 4, 8, 10. 



Brachyopa, spp. Condidea, 2. 



Chilosia, spp. 8. Pyritis, 



Copestylum, i, 4, 8, (fig. 14). Sericomyia (fig. 16). 



Eristalis, spp. i, 2 (8). Volucella, i, 4, 8, (fig. 13.) 



6. Epistoma produced into a long, porrect snout: 

 Rhingia, Lycastrirhyncha, 1,2. 



7. Hind femora with a projection below: 

 Milesia, i, 2. Spilomyia. 4. 

 Pterallastes, 2, .(sp.) 7. Tropidia, 2. 

 Senogaster, 2, 9. 



8. Eyes pubescent: 



Chilosia, spp. Microdon, spp. 3, 4, 10. 



Chrysotoxum, 4. Paragus, 4. 



Ferdinandea. Pipiza, 4. 



Copestylum, i, 4, 5. Psilota. 



Didea, sp. 2. Pyritis, 5. 



Eristalis, spp. i, 2, 5. Rhopalosyrphus, 3, 4, 9, 10. 



Leucozona. Scaeva. 



Mallota, 2, 10, (sp). Syrphus, spp. 



Megametapon, i, 4, 5, 10. Volucella, i, 4, 5; or 4, 5. 



9. Abdomen spatulate or conspicuously narrowed at base: 



Baccha. Rhopalosyrphus, 3, 4, 8, 10. 



Ceriogaster, 2. Salpingogaster, 2. 



Mixogaster, 3, 4, 8, 10. Sphegina. 



Neoascia. Sphyximorpha, 3, 4, n. 



10. Males dichoptic: 



Asemosyrphus, 2. Mixogaster, 3, 4, 9. 



Chalcomyia. Megametapon, i, 4, 5, 8. 



Chamsesyrphus. Pelecocera, n. 



IJelophilus, 2. Rhopalosyrphus, 3, 4, 8, 9. 



Mallota, sp. 2, 8. Pterallastes, 2, 7, (sp.) 

 Microdon, 3, 4, 8. 



11. Arista or style of antennae terminal: 

 Callicera. Merapioidus. 

 Pelecocera, 10. Sphyximorpha, 3, 4, 9. 



