428 PROCEEDINGS OF THE NATIONAL MUSEUM vol. io9 



distinct, small round spots, the posterior one located distinctly 

 proximad of the anterior one; distal pale spot in cell Rs small and 

 round, located in center of cell; two pale spots in cell Mi; only one 

 pale spot each in apices of cells M2, M4 and anal cell; pale spot present 

 behind medial fork but no pale spot in front of mediocubital fork. 

 Macrotrichia very sparse on distal fourth of wing, none located 

 proximad of level of end of costa; costa extending to 0.60 (0.59- 

 0.62, n=9) of distance to wing tip. Halter infuscated. 



Abdomen. — Blackish, cerci yellowish. Spermatheca one, pyriform, 

 measuring 0.057 by 0.038 mm., the base of the duct sclerotized a 

 considerable distance. 



Male genitalia: Ninth sternum very narrow, caudomedian 

 excavation not developed, the posterior membrane not spiculate; 

 ninth tergum short with truncate apex, apicolateral processes long 

 and slender. Basistyle with ventral lobe large and foot-shaped, the 

 posterior heel pointed, dorsal root slender; dististyle long and slender 

 with hooked apex. Aedeagus with basal arch extending to more 

 than half of total length, mesal apex of arch narrow, the basal arms 

 nearly straight and well sclerotized; distal portion tapering to a 

 slender rounded tip, with a subapical, lateral pair of sclerotized 

 points arising near juncture with the arch. Parameres each with 

 small basal knob, stem slender, abruptly bent near base, the straight 

 portion comparatively short with a long ventral lobe distad, beyond 

 which the paramere is very slender, tapering rapidly to a simple fine- 

 pointed tip. 



Distribution: Honduras; Panama. 



Panama records: 



BocAS DEL ToRO PROVINCE: Almiraiite. 



Canal Zone: Fort Davis, Fort Clayton, Loma Boracho, Mindi Dairy. 



Chiriqu! Province: Volcdn. 



Discussion: Culicoides dasyophrus Macfie has a wing pattern 

 almost identical with that of fieldi, but the antennae of dasyophrus 

 are much different, with an antennal ratio of at least 1.5. The 

 antennae oijieldi are much like those of the closely related benarrochei 

 Ortiz; glabellus, new species; leoni Barbosa; and reevesi Wirth, but 

 the presence of two separate, poststigmatic pale spots in cell R5 with 

 the posterior one located distinctly proximad of the anterior one is 

 characteristic only of Jieldi and benarrochei. C. benarrochei can be 

 separated from Jieldi by its shorter second palpal segment (nine- 

 thirteenths as long as third segment), antennal segments xi, xii, 

 XIII, and XIV subequal in length and by the presence of a distinct pale 

 spot in front of the mediocubital fork. The long ventral lobe on the 

 male paramere is diagnostic of Jieldi. 



