DIPT ERA. ^55 



narrow, ending at the third vein, the brown coloration filling out most of the apex of the wing ; basal 

 half of the wing a little infuscated on the front part. 

 Length 6-6*5 millim. 



Hab. Mexico, Teapa in Tabasco (H. H. Smith). 

 Two males. 



4. Psilopus diffusus. 



Psilopus diffusus, Wiedem. Aussereur. zweifl. Ins. ii. p. 221 l ; Loew, Mon. N. A. Dipt. ii. p. 235 *. 



Hab. Mexico, Teapa and Frontera in Tabasco, Medellin near Vera Cruz (H. H. Smith). 

 — Beazil 2 . 



Wiedemann 1 originally gave " Savannah " as the locality for this species : according 

 to Loew (loc. cit.) 9 this was changed on the type-specimen, in Wiedemann's own writing, 

 to Eio Janeiro. Loew gives a complete description from other Brazilian specimens. 

 The species is abundantly represented in the present collection. The width of the 

 black bands of the abdomen is variable, but often much more than indicated by Loew. 

 The greatest discrepancy is in the length of the fore tarsi, which are fully double that 

 of the fore tibia? in the male, and over once and a half in the female. 



5. Psilopus bellulus. 



Psilopus bellulus, Aldrich, Trans. Ent. Soc. Lond. 1896, p. 343 \ 



Hab. Mexico, Cuernavaca in Morelos, Frontera and Teapa in Tabasco, Medellin near 

 Vera Cruz (H H. Smith).— Brazil; Antilles, St. Vincent 1 . 



The Mexican and South-American specimens show some differences from the type, 

 and I at first regarded them as a distinct species. The fore and middle tarsi are much 

 paler, almost white, and the fourth joint of the latter, not being especially distinguished 

 by its whiteness, has on the upper surface a few silvery hairs, making a rather showy 

 fringe. This variation in a secondary sexual character is most unusual and interesting, 

 indicating in this form a plasticity rarely met with in the family. The bands of the 

 wing are frequently faint, but are perceptible in all but very immature specimens. 



Found in abundance by Mr. Smith in S.E. Mexico, and Dr. Williston has given me 

 specimens of it from Brazil. 



6. PsilopUS Ciliipes, sp. n. (Tab. VI. fig. 22, interim tibia and tarsus, J .) 



A dark species. Wings almost entirely hyaline ; feet black, the fore tibiae and base of fore tarsi yellow, 

 tf . Face wide, transversely impressed, with but little whitish pollen • antennas black, second joint with long 

 and dense hair ; front wide, with a considerable amount of pale hair on the sides. Thorax dark green, 

 the sides but thinly pollinose ; halteres distinctly infuscated. Abdomen with broad black bands and 

 moderate bristles ; hypopygium very small, black, the lamellae minute, dark brown. Fore tarsi one-third 

 longer than the tibia?, deeply infuscated for half their length ; middle tibiae on the front side with a 



2z2 



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