KEYS TO FLIES OF THE FAMILIES LONCHAEIDAE, 

 PALLOPTERIDAE, AND SAPROMYZIDAE OF THE 

 EASTERN UNITED STATES, WITH A LIST OF THE 

 SPECIES OF THE DISTRICT OF COLUMBIA REGION. 



By J. R. Malloch and W. L. McAtee, 



Of the United States Biological Survey. 



This paper contains a list of the species in the families Lonchaei- 

 dae, Pallopteridae, and Sapromyzidae that have been collected in the 

 vicinity of the District of Columbia. To facilitate identification of 

 the species so recorded, synopses of the genera and species are in- 

 cluded which embrace all the species known to the authors which 

 have been recorded from the territory east of the Mississippi River, 

 and also all species likely to occur in that territory. 



Many authors consider the families dealt with in this paper as sub- 

 families of Sapromyzidae, but there is very little real similarity be- 

 tween Sapromyzidae and Lonchaeidae. The Pallopteridae appear 

 to be more closely related to the Lonchaeidae than to the Sapromyzi- 

 dae, but there are some very important points of difference between 

 this family and the other two which are emphasized in the discus- 

 sion of the family characters. 



All three families belong to the acalyptrate section of the Cyclor- 

 rhapha, having the abdominal spiracles in the membrane between 

 the tergites and the sternites, close to the former. The auxiliary 

 vein is present and complete, vibrissae are absent, and the basal cells 

 of the wings are complete, the posterior one not prolonged at its 

 apical posterior angle, characters which separate these *families from 

 most of their allies. 



The very well developed frontal lunule of the Lonchaeidae which 

 invades the anterior margin of the interfrontalia more or less tri- 

 angularly and is generally setulose (fig. 2), the presence of a stig- 

 matal and propleural bristle, very small size of preapical tibial 

 bristle, and the complete, though apically indistinct, bisinuate sixth 

 wing vein (fig. 4) separates the family from any other. No family 

 which has the ovipositor very much elongated and sword-shaped, 

 as has this one, has the propleura bare above the bristle and the 



No. 2525— Proceedings U. S. National Museum, Vol. 65, Art. 12. 



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