J. CHESTER BRADLEY. 181 



Body sometimes elongate, the middle coxse being placed far pos- 

 teriorly ; mesopleurse smooth and polished, with a distinct femoral 

 groove; sculpture of a small area on the side of the propodeum of 

 distinctive character, sometimes smooth and polished; fui'cula usu- 

 ally consisting of a long process with very small parallel or diver- 

 gent tynes. 



Posterior legs long; the tarsal claw bifid, the inner ray larger and 

 stouter than the outer one, the latter sometimes nearly obsolete 

 (Figs. 51 and 52). 



Wings hyaline; the venation as shown in Fig. 85. 



Abdomen similar in both sexes, nearly round, the pygidium not 

 produced. 



The size is usually small, the thorax slender and tapering poste- 

 teriorly. The punctation is generally fine or absent. There are 

 13 species, all from the Neotropical region. 



TABLE TO THE SPECIES OF SEM.EOMYIA. 



1. Central American subregion • •• (2). 



Brazilian and Argentine subregions (3). 



2. Mesonotum plainlv punctate; posterior metatarsus plainly longer than the 



remaining joints taken together; cheeks of the male as long as the 

 scape; first joint of the flagellum of the male one and one-half times 

 as long as the ])edicel, second twice as long as the pedicel ; parapsidal 

 grooves obsolete; head coarsely punctured; pronotum with prominent 

 humeral angles. Length 3.5-4 mm- . • -azteka Schletterer, Mexico. 

 Mesonotum smooth and polished, or with a few scarcely noticeable shallow 

 punctures; the posterior metatarsus only as long as the remaining 

 joints together; forehead moderately closely punctate; temples of 

 even width from above to below; scape of the male one-half as long 

 as joints 2 and 3 ; joint 3 two and one-half times as long as the pedi- 

 cel ; pronotum with rounded humeral angles. Black. Length 4 mm. 



■liiiflil Cameron, Panama. 



3. Mesonotum plainly punctured (4). 



Mesonotum not punctured -(8). 



4. Propodeum between the metanotum and the insertion of the petiole punc- 



tured, not wrinkled ; furcula with short divergent tynes (7). 



Propodeum above indistinctly transversely wrinkled; fuicula with parallel 

 tynes (6). 



Propodeum reticulate (5). 



.5. Propodeum on the sides coarsely reticulate; head thickly and moderately 

 finely punctured ; face thickly, very finely and moderately shallowly 

 punctured; mesonotum shiny, polished, the middle piece with spar.'^e 

 shallow punctures; parajisidal and lateral cariii«? distinct. I.,ength 

 5-6 mm magna Enderlein. Peru. 



TRANS. AM. KNT. SOC XXXIV. JUNE, 190P. 



