315 



Family Lauxaniidae 



Homoneura species. 



Rather small flies, rarely more than 6 mm. in length, the auxiliary 

 vein entire and ending in the costa. 



Head variable, the face projecting or retreating, convex, flat or 

 concave, without oral vibrissa although these are rarely poorly de- 

 veloped. Front wide, with two pairs of frontals, the upper pair always 

 reclinate, the lower pair sometimes decussate; ocellars present or minute. 

 Antcnnffi variable, the arista plumose to bare. Thorax with bristles, 

 at least behind the suture; scutellum usually bare except for the mar- 

 ginal bristles; propleural bristle present or absent; one or two sterno- 

 pleurals. Tibise all with preapical bristle. Wing venation complete, 

 the second basal and anal cells short; apical cell usually widely open. 

 Abdomen oval, rarely elongate. 



The adults may be found almost everywhere, but particularly in 

 moist places where they may occur in large numbers. j\Iany of the 

 species are more in evidence in the evening than during the rest of the 

 day. They are not very active and are therefore easily captured. 



The larvffi of at least some of the species mine in plants and are 

 economically important; others live upon decaying vegetation. 



Saprom^'zida; has been used for this family by most American 

 authors but Lauxania is older and should be used. Hendel has pub- 

 lished extensively on the family: many changes have been made since 

 his contribution in Genera Insectorum* and he recognizes many addi- 

 tional genera in his kev to genera. t 



* 1908, Fascicle No. 68. 



t 1925, Encycl. Ent., B. Dipt., pp. 103-142. 



