204 



NORTH AMERICAN DIPTERA 



4. Antennae elongate, the third segment large 5 



Antennae short, the third segment small 7 



5. Eyes pilose or pubescent 6 



Eyes bare Apelleia Bellardi 



6. Third antennal segment without terminal bristles (9, 10) 



*Ocnaea Erickson 

 Third antennal segment with terminal bristly hairs . . Pialeoidea Westwood 



7. Antennae inserted below the middle of the head 8 



Antennae inserted above the middle of the head 9 



8. Third antennal segment with three terminal setse (7, 8). 



Pterodontia Gray 

 Third antennal segment with an apical arista (5, 6) Ogcodes Latreille 



9. Eyes pilose (text figure) Opsebius Costa 



Eyes bare (1, 2) Acrocera Meigen 



» Aldrich. 1932, Pioc. U. S. N. M., Ixxxi, Ait. 9, p. 3. 



Ciytida?. — 1, 2. Acrocera; 3, 4. Philopota ; 5. 6. Ogcodes; 7, 8. Pterodontia; 9. 10, Ocnaea; 

 11, 12, Eulonchus; 13, 14, Lasia. 



