332 NORTH AMERICAN DIPTERA 



Family Agromyzidse — The Leaf Miners 



Small flies, blackish or yellowish in color, the postocellar bristles 

 always present. 



Head usually higher than long-; front with at least three pairs of 

 bristles; ocellars and postocellars present, the latter divergent; face 

 receding or concave in profile; antennae decumbent, the third segment 

 rarely much longer than wide; arista pubescent or bare; oral vibrissae 

 present. Eyes large, the cheeks rarely half as wide as the eye-height. 

 Legs short, the femora with bristles. Wings of moderate size, the ven- 

 ation complete or with the posterior crossvein absent; auxiliary vein 

 more or less fused with the first vein or incomplete. Abdomen more 

 or less depressed. 



The adults occur everywhere and there are few deciduous plants 

 which are not mined by their larva?. Owing to their small size they are 

 easily overlooked although easily recognized. 



The larvae make characteristic mines in the leaves of plants and 

 most of them may be identified by the mines. 



KEY TO GENERA 



1. Arista absent (See Ochthiphilid^, 3 and 5) *Cryptochaetiim Rondani 



Arista present 2 



2. Posterior crossvein present 3 



Posterior crossvein absent 7 



3. Posterior crossvein situated beyond the anterior crossvein 4 



Posterior crossvein situated nearer to the base of the wing than the 



anterior crossvein (10) Napomyza Haliday 



4. Mesopleura with one or more bristles 5 



Mesopleura bare G 



5. Third antennal segment with the upper apex acutely pointed (3, 5). 



Cerodontha Rondaiii 

 Third segment not with an acute point, though sometimes angular (6, 7). 



Agromyza Fallen 



6. Front strongly produced forward, the ocelli situated on the anterior part 



(1, 9) Traginops Coquillett 



Front regular in outline, the ocelli situated near the vertex 8 



7. Fourth vein ending before the wing-tip Antineura Melander 



Fourth vein ending behind the wing-tip (8, 11) Phytomyza Fallen 



8. Apical cell slightly narrowing apically Schildomyia Malloch 



Apical cell widening apically, the costa not extending to the fourth vein 



(2, 4 ) Odinia Desvoidy 



I have not seen this jjenus and its relationshiii is somewhat iloubtful. 



