ABT. 10 TROPICAL AMERICAN DIPTERA — VAN DUZEE 33 



Wings more or less tinffod with yellow in front; veins usually 

 broAvn, except at the root ot" the wing, sometimes they are yellow 

 with the apical j^art brown; third and fourth veins nearly parallel 

 beyond the cross vein, the third bending back a very little toward 

 its tip, fourth ending in the apex of the wing; last section of fifth 

 vein 21, cross vein fifteen-fiftieths of a millimeter long. 



FeiiictJe. — Almost like the male; joints of posterior tarsi as 

 19-22-12-8-10. 



Described from six males and five females ; the ty^pe^ allotype^ and 

 seven yaratyijes were taken by A. H. Jennings, on the beach at Old 

 Panama ; the other two paratypes were taken by A. Busck, March 

 14, 1912, at Corozal, Panama Canal Zone, at lights. 



This would run to thalassitius Van Duzee in the table of species 

 in the Annals Entomological Society of America (vol. 19, p. 36, 

 couplet 19), but it is smaller, the hypopygium much more conspicu- 

 ous, its yellow appendage also being shorter and directed forward, 

 not downward as in that species; this form has the palpi cut off 

 more or less squarely at tip; the first and second joints of posterior 

 tarsi are of equal length, in thalassinus the first joint of hind tarsi 

 is much longer than the second. 



Tyj)e.—Uii\Q, Cat. No. 41047, U.S.N.M. 



Genus MEDETERA Fischer 



Medetera Fischer, Progr. contenant une notice sur une Mouclie carnivore, 

 1819, p. 10. — LoBW, Men. North Amer. Diptera, part 2, 18G4, p. 218, 

 table of species. — Wheeler, Proc. California Acad. Sci., vol. 2, p. 20, 

 table of species. — Aldkich, Trans. Entom. Soc. London, part 3, 1896, p. 

 337. — Van Duzee, Proc. California Acad. Sci., vol. 9, p. 257, table of 

 species. 



There are before me eight species of this genus, all taken in 

 Guatemala except hella. All are bright but rather dark green, 

 nearly 3 mm. long, have at least two pairs of femora black, the 

 tibiae and tarsi yellow, the latter sometimes more or less blackened 

 (in hella the tibiae and tarsi are black) ; all have two pair^ of 

 scutellar bristles. These form a very distinct group in the genus; 

 they may be separated in the following table : 



KEY TO NEOTROPICAL SPECIES OF MEDETERA 



1. All tarsi plain 2. 



Fore tarsi modified 4. 



2. Legs and feet wholly black bella, new species. 



Tibiae and tarsi yellow, tarsi more or less darkened at tip 3. 



3. Antennae black planipes Van Duzee. 



Antennae yellow pallidicornis, new species. 



4. Fore and middle femora largely black, hind femora yellow 5. 



All femora largely black 6. 



2613—28 3 



