36f 



Family Chamaemyidae 



Small flies, usually iiirayish in color. 



Front wide, with at most two pairs of bristles, often bare; face 

 gently concave or strongly receding; oral vibrissse absent; postvertieals 

 eonvei'oent or absent; ]iroboscis short: antennae short. ]\Iesonotum with 

 or Avithoiit bristles; ])rothoracic bristle absent; one sternopleural; 

 mesopleura usually liare, rarely setnlose. Front femora with bristles; 

 tibia* Avithout preapical bristle. Wings with the auxiliary vein entire, 

 sometimes touching the first vein before its end; anal vein not reaching 

 nearly to the wing margin, the anal and second basal cells always 

 complete; costa not broken. Abdomen short or slightly elongate. 



The larvae of Leucopis are predaeeous upon aphids and I have 

 found them commonly on plant lice attacking thistle, Oenothera, bur- 

 dock, etc. They are somewhat triangular in outline, the posterior 

 spiracles being located at the posterior corners of the body and strongly 

 projecting. All I have seen have been pale yellowish, with a darker 

 median vitta. They usually conceal themselves under the aphids or in 

 the axils of leaves. Pupation usually takes place in the axils, the head 

 pointing upward on the stem, but the location is variable. 



KEY TO GENERA 



1. Front without distinct bristles 2 



Front with one or two pairs of strong bristles 4 



2. Arista absent (Agromyzidae) (3, 5) Cryptochaetum Rondani 



Arista present 3 



3. Shining black species Paraleucopis Malloch 



Densely cinereous pollinose species (2, 13) *Leucopis Meigen 



4. Face very strongly receding, the head pointed (1, 10). 



Acrometopia Schiner 

 Face only a little retreating 5 



5. Three or four pairs of doi'socentrals 6 



Two pairs of dorsocentrals (4, 8) fPseudodinia Coquillett 



6. Three pairs of dorsocentrals (Ochthiphila Fallen) (6, 7, 12). 



Chamaemyia Meigen 

 Foul' pairs of dorsocentrals (9. 11) $Plunomia, n. g. 



* Malloch, 1921. Bull. 111. Nat. Hist. Survey, xiii, p. 349. 



t A paratype of Pseudodinia polita Malloch lacks the two stronjr frontals and I would 

 place it in Paraleucopis but it lacks the setula; on the underside of the costa. 

 % For Chamaemyia elegans Malloch, 1921, not Panzer. 



