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anteriorly on forecoxa; fore- and midfemora; fore- and mid tibiae, 

 but slightly darkened. Abdomen with terga shiny black except 

 for narrow yellow hind margins on I-V, shghtly widened laterally; 

 sterna I-V mostly yellow, a dark area on side of sternum II. Wing 

 length 5.5 mm. Terminalia as figured (fig. 1). 



Holotype: d", South Chiltern, 1600 feet, Feb. 19, 1965 (Evans), 

 (USNM 69076). 



This species would run in the key of Lane and Andretta (1958) 

 to 0. chavantesi Lane and Andretta, but the color pattern of the head, 

 thorax, coxae, and sterna, and the structures of the terminalia are 

 different. The terminalia are closest to those of similans Lane and 

 Andretta, but the appendages lying dorsad of the cerci are broad 



1 ife 



Figure 1. — Olbiogaster evansi, new species, male terminalia, dorsal view: a, cerci and at- 

 tached appendages; b, aedeagus and attached appendages (drawn by Arthur D. Cushman). 



and flat, not narrow and rodlike, and in similans the tergal yellow 

 bands are much broader and the steina are mostly black. 



This species is dedicated to the coDector, Howard E. Evans. 



Family Bibionidae 



The only Bibionidae collected on Dominica by the Bredin-Ai'chbold 

 Smithsonian Survey consisted of 21 specimens of an apparently un- 

 described species of the genus Plecia Wiedemann. I take this oppor- 

 tunity to describe it. 



Plecia porca, new species 



An entirely dark brownish-black species with foiu- shiny stripes on 

 notum and fumose wings. It runs to couplet 5 of Hardy's key (1945, 



